A process to produce an enrichment feed

IS 2 688 198 T3

DESCRIPTION

A procedure for producing an enrichment feed

FIELD OF THE INVENTION

This invention relates to a process and the resulting enriched carboxylic acid compositions produced by contacting a carboxylic acid composition with an enrichment feed in an enrichment zone to form an enriched carboxylic acid composition.

BACKGROUND OF THE INVENTION:

Terephthalic acid is produced commercially by oxidation of paraxylene in the presence of at least one catalyst, such as, for example, Co, Mn and Br catalyst and a solvent, typically acetic acid. Terephthalic acid is typically prepared in a way to remove impurities formed as a result of oxidation of paraxylene.

Terephthalic acid (TPA) is an intermediate in the production of condensation polymers and copolymers, especially polyesters and copolyesters for plastics, fibers, films, coatings, containers, and other items. Of particular commercial importance is polyethylene terephthalate, referred to as PET, a polyester of TPA and ethylene glycol (EG), as well as related copolyesters. Commercial processes for the manufacture of TPA are often based on the multivalent transition metal catalyzed oxidation of p-xylene, generally with a bromide promoter in an acetic acid solvent. Due to the limited solubility of TPA in acetic acid under practical oxidation conditions, a crystalline agglomerate suspension containing primarily TPA is generally formed in the oxidation reactor. Typically, the TPA oxidant slurry is removed from the reactor, and the TPA solids are separated from the oxidant mother liquor using conventional liquid-solid separation techniques. The oxidizing mother liquor stream, which contains most of the catalyst and promoter used in the process, is recycled to the oxidation reactor. In addition to the catalyst and promoter, the oxidizing mother liquor stream also contains dissolved TPA and many by-products, impurities, and other compounds. These other compounds, oxidation by-products, and impurities arise partially from compounds present in minor amounts in the p-xylene feed stream. Other oxidation compounds and by-products arise due to incomplete oxidation of p-xylene resulting in partially oxidized products. Still other compounds and oxidation by-products result from competitive side reactions formed as a result of the oxidation of p-xylene to terephthalic acid. Patents disclosing the production of terephthalic acid are US Patent No. 4,158,738 and No. 3,996,271.

Many of the compounds in the oxidant mother liquor stream that are recycled are relatively inert to further oxidation, but are not inert to further reaction including decomposition and conversion to other compounds. Such compounds include, for example, isophthalic acid (IPA), benzoic acid, and phthalic acid. Compounds are also present in the oxidizing mother liquor stream, which may undergo further oxidation, such as, for example, in the case of oxidation of p-xylene (also known as 1,4-dimethylbenzene), compounds such as 4-carboxybenzaldehyde, p-toluic acid, p-tolualdehyde and terephthaldehyde. Compounds that are relatively inert to oxidation and that are not otherwise removed from the process tend to accumulate in the oxidizing mother liquor stream upon recycling.

Conventionally, crude terephthalic acid (CTA) is purified by conversion to a dimethyl ester or by dissolution in water with subsequent hydrogenation over conventional hydrogenation catalysts. More recently, secondary oxidative treatments have been used instead of hydrogenation to produce polymer grade TPA. It is desirable to minimize the concentration of impurities in the mother liquor and thereby facilitate the subsequent purification of TPA. In some cases, it is not possible to produce a purified polymer grade TPA unless some means are used to remove impurities from the oxidizing mother liquor stream.

A commonly used impurity removal technique in the chemical processing industry is to switch or "purge" a portion of the mother water stream as a recycle stream. Typically, the purge stream is simply removed or, if economically justified, undergoes various treatments to remove unwanted impurities while recovering valuable components. An example of this purging procedure is US Patent No. 4,939,297.

IS 2 688 198 T3

Purification of CTA to produce purified terephthalic acid (PTA) increases the cost of manufacturing the PTA. It is desirable to maximize the concentration of by-products, impurities, and other compounds in terephthalic acid as long as terephthalic acid remains useful, especially in the manufacture of poly (ethylene terephthalate) (PET) polymer and articles therefrom, such as film, containers and fiber.

WO 2006/049818 refers to the removal of impurities and the recovery of mother liquor and wash filtrate from an oxidative purge stream produced in the synthesis of carboxylic acid, typically terephthalic. More particularly, the process involves removing impurities and recovering a mother liquor and washed filtrate from an oxidative purge stream and then routing the mother liquor and / or washed filtrate to an oxidation zone.

US 4,356,319 discloses a process for recovering the catalyst in active form from acetic mother liquors from the synthesis of terephthalic acid. From said mother liquor, after the elimination of water, an amount of 70 to 90% of the CH3COOH present in it is eliminated by evaporation. The concentrated water is cooled below 60 ° C and the solid that precipitates is collected and recycled for reuse in synthesis.

Document CA 2,248,288 refers to a mother liquor, from a primary solid liquid separation process to separate aromatic carboxylic acid crystals from a suspension thereof in mother liquor, which is divided into a recycling fraction and a fraction of purge. The recycle fraction is returned to a reactor in which aromatic carboxylic acid is formed by oxidation in the liquid phase of a precursor thereof. The purge fraction is concentrated in an evaporator to recover the solvent and produce a further disposal or treatment residue.

WO2006 / 125144 relates to a resulting enriched carboxylic acid process and compositions produced by contacting a carboxylic acid composition with an enrichment feed in an enrichment zone to form an enriched carboxylic acid composition. This disclosure also relates to a process and the resulting compositions for removing the catalyst from a cooled carboxylic acid composition.

An example of utility is the improved performance in a carboxylic acid process, particularly a terephthalic acid process. Another utility of this invention is the flexibility of controlling the fate of specific compounds in the process. For example, a portion of specific compounds can be conserved in the product in a catalyst removal zone and / or enriched in the product in the enrichment zones so that they exit with the product stream, or are allowed to exit the process. Yet another utility is that the process allows the option of placing compounds in the product stream that are not in the TPA process. Another utility is the option of adding a comonomer, to the TPA product stream, for example, IPA can be added.

SUMMARY OF THE INVENTION

According to claim 1, there is provided a method of producing an enrichment feed.

The procedure includes:

(a) subjecting a solvent-rich stream to a solid concentration zone to form a concentrated solvent-rich stream; wherein said solvent-rich stream comprises at least one solvent, at least one carboxylic acid, and at least one oxidation by-product; wherein said solvent rich stream has a solids content of less than 5% by weight; wherein the amount of solids in said concentrated solvent-rich stream is greater than the amount of solids in said solvent-rich stream by weight;

(b) subjecting said concentrated solvent-rich stream to a concentrated SLS zone to form a mother liquor stream and said enrichment feed; wherein said zone of concentrated SLS comprises at least one device for separating liquid and solid; Y

ES 2 688 198 T3 (c) recycling at least a portion of said enrichment feed at any point in a TPA production process after a primary oxidation zone and before a drying zone:

wherein said at least carboxylic acid is terephthalic acid; and wherein the enrichment compound (s) of said re-enrichment feed (220) comprise at least one compound selected from the group consisting of isophthalic acid, phthalic acid, benzene-tricarboxylic acid isomers, dicarboxybiphenyl isomers, dicarboxystilbene isomers, tricarboxybiphenyl isomers, tricarboxybenzophenone isomers, dicarboxybenzophenone isomers, dicarboxybenzyl isomers, form-acet-hydroxybenzoic acid isomers, acet-hydroxymethylbenzoic acid isomers, isomers of bromotoluic acid, bromo-benzoic acid, bromo-acetic acid, tolualdehyde isomers and phthalaldehyde isomers; wherein said solid liquid separation device is a spark plug filter, and where 5% by weight of said enrichment feed (220) is recycled so that an increase of b * in the TPA product is less than 2 compared to a TPA production process without any enrichment feed (220) or where 10% by weight of said enrichment feed (220) is recycled so that an increase in b * in the TPA product is less than 4 compared to a TPA production process without any feed of enrichment (220).

BRIEF DESCRIPTION OF THE DRAWINGS

Figures 1 A and B illustrate an embodiment of the invention where a dry carboxylic acid composition 280 is produced.

Figure 2 illustrates various embodiments of the invention where multiple liquid displacement zones 40 can be used.

Figure 3 illustrates one embodiment of the invention where a crystallized suspension composition 160 can be produced by multiple different procedures.

Figure 4 illustrates an embodiment of the invention where the crude carboxylic acid composition or a suspension composition can be produced by multiple different procedures.

Figure 5 illustrates an embodiment of the invention where a post-catalyst removal composition 200 is produced from a carboxylic acid composition 214 in a catalyst removal zone 180.

Figure 6 illustrates an embodiment of the invention where a catalyst removal zone 180 and an enrichment zone 210 are used to produce an enriched composition 240 from a cooled carboxylic acid composition 170.

Figure 7 illustrates an embodiment of the invention where an enriched composition 240 is produced from a post-catalyst removal composition 200 in an enrichment zone 210 ..

Figure 8 illustrates an embodiment of the invention showing multiple enrichment feed points 220.

Figure 9 illustrates various embodiments of the invention where a carboxylic acid composition 214 and / or a crystallized suspension composition 160 are enriched.

Figure 10 illustrates various embodiments of the invention where a carboxylic acid composition 214 is enriched in a prolonged enrichment zone 213.

Figure 11 illustrates various embodiments of the invention where enrichment zone 210 and catalyst removal zone 180 may be combined into at least one combined enrichment / catalyst removal zone 181 or at least one device that fulfills both functions.

Figures 12, 13, 14 and 15 illustrate an embodiment of the invention showing multiple enrichment feeds 220 in a given process.

Figure 16 illustrates an embodiment of the invention where an enriched composition 240 is sent directly to an esterification reaction zone 610.

Figure 17 illustrates an embodiment of the invention where a water-wet cake composition 246 is sent directly to an esterification reactor zone 610.

Figure 18 illustrates an embodiment of the invention where an aromatic feedstock 10 is used to produce a post-catalyst removal composition 200.

Figure 19 illustrates an embodiment of the invention where an aromatic raw material 10 is used to produce an enriched composition240.

Figure 20 A and B illustrate an embodiment of the invention where catalyst removal zone 180 is optional, and enrichment zone 210 is required.

Figures 21, 22, and 23 illustrate the change in L *, a *, and b * color versus plug filter material in the PTA product. The PTA product corresponds to the dry carboxylic acid product 280y where the dry carboxylic acid product 280 comprises terephthalic acid.

IS 2 688 198 T3

Figure 24 illustrates an embodiment of the invention where an enrichment feed 220 is produced from a solvent rich stream 900.

DETAILED DESCRIPTION OF THE INVENTION The present invention may be more easily understood by reference to the following detailed description of the preferred embodiments of the invention and the examples included in this invention and to the figures and their description above and below.

Before the present compounds, compositions, articles, devices, and / or procedures are disclosed and described, it should be understood that this invention is not limited to specific synthetic procedures, specific procedures, or particular apparatus, as such, of course, they may vary. It should also be understood that the terminology used in this invention is for the purpose of describing particular embodiments only and is not intended to be limiting.

In this specification and in the claims that follow, reference will be made to a series of terms that will be defined with the following meanings:

As used in the specification and appended claims, the singular forms "a," "an, and" the "include plural references unless the context clearly indicates otherwise. Thus, for example, reference to a catalyst removal zone includes one or more catalyst removal zones.

Ranges can be expressed in this invention from "about" one particular value, and / or to "about" another particular value. When such a range is expressed, another embodiment includes from the particular value and / or to the other particular value. Similarly, when the values ​​are expressed as approximations, by using the antecedent "about", the particular value will be understood to form another embodiment. It will be further understood that the end points of each of the intervals are significant both in relation to the other end point, and independently of the other end point.

"Optional" or "optionally" means that the event or circumstance described below may or may not occur, and that the description includes aspects where the event or circumstance occurs and aspects where it does not occur. For example, the term "optionally heated" means that the material may or may not be heated and that such term includes both heated and non-heated processes. Although the numerical ranges and parameters that state the broad scope of the invention are approximations, the numerical values ​​set forth in the specific examples are indicated as precisely as possible. Any numerical value, however, intrinsically contains certain errors that necessarily result from the standard deviation found in the respective test measurements.

The ranges stated in this disclosure and claims are intended to include the entire range specifically and not just the end point (s). For example, a range indicated as 0 to 10 is intended to report all integers between 0 and 10 such as 1, 2, 3, 4, etc., all fractional numbers between 0 and 10, for example 1, 5, 2,3, 4,57, 6,113, etc., and the endpoints 0 and 10. Furthermore, a range associated with chemical substituent groups such as, for example, "C1 to C5 hydrocarbons" is intended to include and specifically disclose C1 and C5 hydrocarbons as well as C2, C3, and C4 hydrocarbons.

In one embodiment of the invention, a postcatalyst removal composition 200 is optionally contacted with an enrichment feed 220 in an enrichment zone 210. A 70 suspension composition or a 160 crystallized suspension composition or a cooled 170 carboxylic acid composition or a crude carboxylic acid composition 30 can be manufactured in any conventional process known in the art to produce a carboxylic acid composition. The 70 slurry composition, or the 160 crystallized slurry composition, the 170 cooled carboxylic acid composition, the 30 crude carboxylic acid composition, are then subsequently used to produce a 280 dry carboxylic acid composition, or a 240 enriched composition, or a 260 dehydrated cake composition. For example, a procedure for preparing a post-catalyst removal composition 200 is provided in Figures 1A and B.

Step (a) in Figure 1A comprises oxidizing an aromatic raw material 10 in a primary oxidation zone 20 to form a crude carboxylic acid composition 30. The aromatic raw material 10 comprises at least one oxidizable compound, at least one solvent and at least one catalyst.

One embodiment of the invention relates to the partial oxidation in liquid phase of an oxidizable compound. Bliss

ES 2 688 198 T3 oxidation is preferably carried out in the liquid phase of a multi-phase reaction medium contained in a stirred reactor or reactors. Suitable stirred reactors include, for example, bubble stirred reactors (eg, bubble column reactors) and mechanically stirred reactors (eg, continuously stirred tank reactors). The liquid phase oxidation is preferably carried out in a bubble column reactor.

As used in this invention, the term "bubble column reactor" will denote a reactor for facilitating chemical reactions in a multi-stage reaction medium, where agitation of the reaction medium is provided primarily by the upward movement of bubbles. of gas through the reaction medium. As used in this invention, the term "agitation" will indicate the work dissipated in the reaction medium that causes fluid flow and / or mixing. As used in this invention, the terms "majority", "primarily" and "predominantly" will mean more than 50 percent.

The oxidizable compound present in the aromatic raw material 10 preferably comprises at least one hydrocarbyl group. More preferably, the oxidizable compound is an aromatic compound. Even more preferably, the oxidizable compound is an aromatic compound with at least one attached hydrocarbyl group or at least one attached substituted hydrocarbyl group or at least one attached heteroatom or at least one attached carboxylic acid (COOH) function. Even more preferably, the oxidizable compound is an aromatic compound with at least one attached hydrocarbyl group or at least one substituted hydrocarbyl group attached with each attached group comprising 1 to 5 carbon atoms. Still even more preferably, the oxidizable compound is an aromatic compound having exactly two groups attached with each attached group comprising exactly one carbon atom and consisting of methyl groups and / or substituted methyl groups and / or at most one carboxylic acid group. . Even more preferably, the oxidizable compound is para-xylene, meta-xylene, para-tolualdehyde, meta-tolualdehyde, para-toluic acid, meta-toluic acid and / or acetaldehyde. Most preferably, the oxidizable compound is paraxylene.

A "hydrocarbyl group", as defined in this invention, is at least one carbon atom that is attached only to hydrogen atoms or to other carbon atoms. A "substituted hydrocarbyl group", as defined in this invention, is at least one carbon atom bonded to at least one hetero atom and to at least one hydrogen atom. "Heteroatoms", as defined in this invention, are all atoms other than carbon and hydrogen atoms. "Aromatic compounds" as defined in this invention comprise an aromatic ring, preferably having at least 6 carbon atoms, even more preferably having only carbon atoms as part of the ring. Suitable examples of such aromatic rings include, but are not limited to, benzene, biphenyl, terphenyl, naphthalene, and other carbon-based fused aromatic rings.

Suitable examples of the oxidizable compound include aliphatic hydrocarbons (eg, alkanes, branched alkanes, cyclic alkanes, aliphatic alkenes, branched alkenes, and cyclic alkenes); aliphatic aldehydes (eg, acetaldehyde, propionaldehyde, isobutyraldehyde, and n-butyraldehyde); aliphatic alcohols (eg, ethanol, isopropanol, npropanol, n-butanol, and isobutanol); aliphatic ketones (eg. g., dimethyl ketone, ethyl methyl ketone, diethyl ketone and isopropyl methyl ketone); aliphatic esters (eg, methyl formate, methyl acetate, ethyl acetate); peroxides, peracids, and aliphatic hydroperoxides (eg, t-butyl hydroperoxide, peracetic acid, and di-t-butyl hydroperoxide); aliphatic compounds with groups that are combinations of the above aliphatic species plus other heteroatoms (e.g. g., aliphatic compounds comprising one or more molecular segments of hydrocarbons, aldehydes, alcohols, ketones, esters, peroxides, peracids and / or hydroperoxides in combination with sodium, bromine, cobalt, manganese and zirconium); various benzene rings, naphthalene rings, biphenyls, terphenyls, and other aromatic groups with one or more hydrocarbyl groups attached (e.g. e.g., toluene, ethylbenzene, isopropylbenzene, n-propylbenzene, neopentylbenzene, para-xylene, meta-xylene, ortho-xylene, all isomers of trirenethylbenzenes, all isomers of tetramethylbenzenes, pentamethylbenzene, hexamethylbenzene, all isomers of ethylbenzene, all isomers of ethylbenzene , all isomers of diethylbenzenes, all isomers of ethyl-dimethylbenzenes, all isomers of dimethylnaphthalenes, all isomers of ethyl-methylnaphthalenes, all isomers of diethylnaphthalenes, all isomers of dimethylbiphenyl, all isomers of ethyl-methylbiphenyl, and all isomers of diethylbiphenyl, stilbene and with one or more attached hydrocarbyl groups, fluorene and with one or more attached hydrocarbyl groups, anthracene and with one or more attached hydrocarbyl groups , and diphenylethane and with one or more hydrocarbyl groups attached); various benzene rings, naphthalene rings, biphenyls, terphenyl, and other aromatic groups with one or more attached hydrocarbyl groups and / or one or more attached heteroatoms, which can be attached to other atoms or groups of atoms (eg, phenol, all isomers of methylphenols, all isomers of dimethylphenols, all isomers of naphthols, benzylmethyl ether, all isomers of bromophenols, bromobenzene, all isomers of bromotoluenes including alpha6

ES 2 688 198 T3 bromotoluene, dibromobenzene, cobalt naphthenate, and all isomers of bromobiphenyl); various benzene rings, naphthalene rings, biphenyls, terphenyl, and other aromatic groups with one or more attached hydrocarbyl groups and / or one or more attached heteroatoms and / or one or more further attached substituted hydrocarbyl groups (e.g. e.g., benzaldehyde, all isomers of bromobenzaldehydes, all isomers of brominated tolualdehydes including all isomers of alpha-bromotolualdehydes, all isomers of hydroxybenzaldehyde, all isomers of bromo-hydroxybenzaldehyde, all isomers of isomers of benzene aldehydes, all isomers of benzene dicarboxyls of benzene tricarboxaldehydes, para-tolualdehyde, meta-tolualdehyde, ortho-tolualdehyde, all isomers of toluene dicarboxaldehydes, all isomers of toluene tricarboxaldehydes, all isomers of toluene tetracarboxaldehydes, all isomers of dimethylbenzene dicarboxialdehydes, all isomers of dimethylbenzene tricarboxialdehydes, all isomers of dimethylbenzene tetracarboxaldehydes, all isomers of tricarboxaldehyde dimethylbenzene, all isomers of tricarboxaldehyde from trimethylbenzene dicarboxaldehydes, tetramethylbenzene dicarboxaldehyde, hydroxymethylbenzene, all isomers of hydroxymethyl toluenes, all isomers of hydroxymethyl-bromotoluenes, all isomers of hydroxymethyl-tolualdehydes, all isomers of hydroxymethyl-bromotolualdehydes, benzyl hydroperoxide, benzoyl hydroperoxide, all isomers of all toloxyl methyl-isomers, and hydroperoxide methylphenol methyl hydroperoxides); various benzene rings, naphthalene rings, biphenyls, terphenyl and other aromatic groups with one or more selected groups attached, groups selected representing attached hydrocarbyl groups and / or heteroatoms and / or substituted hydrocarbyl groups and / or carboxylic acid groups and / or peroxy acid groups (e.g. e.g., benzoic acid, para-toluic acid, metatoluic acid, ortho-toluic acid, all isomers of ethylbenzoic acids, all isomers of propylbenzoic acids, all isomers of butylbenzoic acids, all isomers of pentylbenzoic acids, all isomers of dimethylbenzoic acids, all isomers of ethylmethylbenzoic acids, pentamethylbenzoic acid, all isomers of diethylbenzoic acids, all isomers of benzene dicarboxylic acids, all isomers of benzene tricarboxylic acids, all isomers of methylbenzenedicarboxylic acids, all isomers of dimethylbenzenedicarboxylic acids, all isomers of methylbenzenetricarboxylic acids, all isomers of bromobenzoic acids, all isomers of dibromomobenzoic acids including all isomers of bromobenzoic acids alpha-bromotoluic acids, tolyl acetic acid, all isomers of hydroxybenzoic acid isomers, all sisomers of hydroxymethylbenzoic acids, all isomers of hydroxytoluic acids, all isomers of hydroxymethyltoluic acids, all isomers of hydroxymethyl benzenedicarboxylic acids, all isomers of hydroxybromobenzoic acids, all isomers of hydroxybromotulic acids, all isomers of hydroxybromotulic acids bromobenzoics, all isomers of carboxybenzaldehydes, all isomers of dicarboxybenzaldehydes, perbenzoic acid, all isomers of hydroperoxymethyl benzoic acids, all isomers of isomers of hydroxyperomethyl-hydroxybenzoic acid, all isomers of hydroperoxycarbonylbenzoic acids, all isomers of hydroperoxycarbonyl toluenes, all isomers of methylbiphenylcarboxylic acids, all isomers of dimethylbiphenylcarboxylic acids, all isomers of dimethylbiphenylcarboxylic acids isomers of methylbiphenyltricarboxylic acids, all isomers of biphenyltricarboxylic acids, all isomers of stilbene with one or more selected groups, all isomers of fluorenone with one or more selected groups attached, all isomers of naphthalene with one or more selected groups attached, benzyl, all isomers of benzyl with one or more groups selected linked, benzophenone, all isomers of benzophenone with one or more selected groups attached, anthraquinone, all isomers of anthraquinone with one or more selected groups attached, all diphenylethane isomers with one or more selected groups attached, benzocoumarin, and all benzocoumarin isomers with one or more selected groups attached).

It should be understood that the oxidizable compound present in the liquid phase feed may comprise a combination of two or more different oxidizable chemicals. These two or more different chemical materials can be fed mixed together into the aromatic feedstock 10 or they can be fed separately in multiple feed streams. For example, an aromatic feedstock comprising paraxylene, meta-xylene, para-tolualdehyde, para-toluic acid, and acetaldehyde can be fed to the reactor through a single inlet or multiple separate inlets.

The solvent present in the aromatic raw material 10 preferably comprises an acid component and a water component. In one embodiment, the solvent is preferably present in aromatic feedstock 10 at a concentration in the range of about 60 to about 98 weight percent, more preferably in the range of about 80 to about 96 weight percent, and most preferably in the range of 85 to 94 percent by weight. The acid component of the solvent is preferably an organic low molecular weight monocarboxylic acid having 1-6 carbon atoms, more preferably 2 carbon atoms. Most preferably, the acid component of the solvent is acetic acid. Preferably, the acid component constitutes at least about 75 percent by weight of the

ES 2 688 198 T3 solvent, more preferably at least about 80 percent by weight of the solvent, and most preferably 85 to 98 percent by weight of the solvent, the balance being water.

Suitable solvents include, but are not limited to, aliphatic monocarboxylic acids, preferably containing 2 to 6 carbon atoms, or benzoic acid and mixtures thereof and mixtures of these compounds with water.

The catalyst system present in the aromatic feedstock 10 is preferably a homogeneous liquid phase catalyst system capable of promoting oxidation (including partial oxidation) of the oxidizable compound. More preferably, the catalyst system comprises at least one multivalent transition metal. Even more preferably, the multivalent transition metal comprises cobalt. Even more preferably, the catalyst system comprises cobalt and bromine. Most preferably, the catalyst system comprises cobalt, bromine, and manganese.

When cobalt is present in the catalyst system, it is preferred that the amount of cobalt present in the aromatic raw material 10 is such that the cobalt concentration in the liquid phase of the reaction medium in the primary oxidation zone 20 is kept in the range from about 300 to about 6,000 parts per million by weight (ppmw), more preferably in the range of from about 700 to about 4,200 ppmw, and most preferably in the range of 1,200 to 3,000 ppmw. When bromine is present in the catalyst system, it is preferred that the amount of bromine present in the raw material aromatic is such that the bromine concentration in the liquid phase of the reaction medium is kept in the range of about 300 to about 5,000 . ppmw, more preferably in the range of about 600 to about 4,000 ppmw, and most preferably in the range of 900 to 3,000 ppmw. When manganese is present in the catalyst system, it is preferred that the amount of manganese present in the aromatic raw material 10 is such that the manganese concentration in the liquid phase of the reaction medium is kept in the range of about 20 to about 1,000. ppmw, more preferably in the range of about 40 to about 500 ppmw, most preferably in the range of 50 to 200 ppmw.

The concentrations of cobalt, bromine and / or manganese in the liquid phase of the reaction medium, given above, are expressed on a time-averaged and volume-averaged basis. As used in this invention, the term "time averaged" will denote an average of at least 10 measurements taken over a continuous 100 second period of time. As used in this invention, the term "volume averaged" will denote an average of at least 10 measurements taken at uniform three-dimensional spacings throughout a given volume.

The weight ratio of cobalt to bromine (Co: Br) in the catalyst system introduced into primary oxidation zone 20 is preferably in the range of about 0.25: 1 to about 4: 1, more preferably in the range of about 0.5: 1 to about 3: 1, and most preferably in the range of 0.75: 1 to 2: 1. The weight ratio of cobalt to manganese (Co: Mn) in the catalyst system introduced into primary oxidation zone 20 is preferably in the range of about 0.3: 1 to about 40: 1, more preferably in the range of about 5: 1 to about 30: 1, and most preferably in the range of 10: 1 to 25: 1.

The aromatic raw material 10 introduced into the primary oxidation zone 20 may include small amounts of compounds such as, for example, meta-xylene, ortho-xylene, toluene, ethylbenzene, 4-carboxybenzaldehyde (4-CBA), benzoic acid, para- toluic, paratoluic aldehyde, alpha bromo para-toluic acid, isophthalic acid, phthalic acid, trimellitic acid, polyaromatics and / or suspended particles.

Step (b) optionally comprises removing at least a portion of oxidation by-products from a crude carboxylic acid composition 30 in a liquid displacement zone 40 to form a suspension composition 70.

A crude carboxylic acid composition 30 comprises at least one carboxylic acid, at least one catalyst, at least one solvent, and at least one oxidation by-product at least a portion of which is extracted through line 60. Oxidation by-products typically comprise at least one or more of the following classes of compounds and their isomers: carboxylic acids, aldehydes, hydroxyaldehydes, carboxyaldehydes, ketones, alcohols and

ES 2 688 198 T3 hydrocarbons. In the case of p-xylene oxidation, the oxidation by-products typically comprise at least one of the following compounds: 4-carboxybenzaldehyde, p-toluic acid, p-tolualdehyde, isophthalic acid, phthalic acid, benzoic acid, trimellitic acid, 4,4'-dicarboxybiphenyl, 2,6- and 2,7-dicarboxyfluorenone, 2,6-dicarboxyanthraquinone, 4,4'-dicarboxybenzophenone, 4,4'-dicarboxybiphenyl and α-bromo-p-toluic acid. The solvent typically comprises acetic acid, but can be any solvent mentioned above.

The crude carboxylic acid composition 30 is produced by oxidizing in a primary oxidation zone 20 an aromatic raw material 10. In one embodiment, the aromatic raw material 10 comprises paraxylene. The primary oxidation zone 20 comprises at least one oxidation reactor. The crude carboxylic acid composition 30 comprises at least one carboxylic acid.

In one embodiment of the invention, the oxidation reactor can be operated at temperatures between about 110 ° C to about 200 ° C; another range is between about 140 ° C and about 170 ° C. Typically, the oxidizable compound in the aromatic raw material 10 is paraxylene, and the carboxylic acid produced is terephthalic acid. In one embodiment of the invention, the primary oxidation zone 20 comprises a column of bubbles.

Carboxylic acids include aromatic carboxylic acids produced by controlled oxidation of an organic substrate or any carboxylic acid produced by oxidation of the aforementioned oxidizable compounds. Said aromatic carboxylic acids include compounds with at least one carboxylic acid group attached to a carbon atom that is part of an aromatic ring, preferably having at least 6 carbon atoms, even more preferably having only carbon atoms. Suitable examples of such aromatic rings include, but are not limited to, benzene, biphenyl, terphenyl, naphthalene, and other carbon-based fused aromatic rings. Examples of suitable carboxylic acids include, but are not limited to, terephthalic acid, benzoic acid, p-toluic, phthalic acid, isophthalic acid, trimellitic acid, naphthalene dicarboxylic acid, and 2,5-diphenylterephthalic acid.

The crude suspension of terephthalic acid is conventionally produced by the liquid phase oxidation of paraxylene in the presence of a suitable oxidation catalyst. In another embodiment of the invention, suitable catalysts include, but are not limited to, cobalt, manganese, and bromine compounds, which are soluble in the selected solvent.

The crude carboxylic acid composition in conduit 30 is optionally fed to a liquid displacement zone 40 capable of removing a portion of the liquid contained in the crude carboxylic acid composition 30 to produce the suspension composition in conduit 70. In embodiments of the invention , a

<td>portion means that at least 5% by weight of the liquid is removed. In another embodiment of the invention, a portion</td>

<td>means that at least 10% by weight of the liquid is removed. In another embodiment of the invention, a portion</td>

<td>means that at least 15% by weight of the liquid is removed. In another embodiment of the invention, a portion</td>

<td>means that at least 25% by weight of the liquid is removed. In another embodiment of the invention, a portion</td>

<td>means that at least 35% by weight of the liquid is removed. In another embodiment of the invention, a portion</td>

<td>means that at least 45% by weight of the liquid is removed. In another embodiment of the invention, a portion</td>

<td>means that at least 55% by weight of the liquid is removed. In another embodiment of the invention, a portion</td>

<td>means that at least 65% by weight of the liquid is removed. In another embodiment of the invention, a portion</td>

<td>means that at least 75% by weight of the liquid is removed. In another embodiment of the invention, a portion</td>

<td>means that at least 85% by weight of the liquid is removed. In another embodiment of the invention, a portion may</td>

mean that any part up to and including the total weight of the liquid is removed.

Removal of a portion of the liquid to produce a suspension composition in conduit 70 can be accomplished by any means known in the art. Typically, the liquid displacement zone 40 comprises a liquid-solid separator which is selected from the group consisting of a decanter centrifuge, a disk stacking centrifuge, a vacuum belt filter, a vacuum rotary filter, a rotary pressure filter, a perforated basket centrifuge and the like. The crude carboxylic acid composition in conduit 30 is fed to liquid displacement zone 40 which comprises at least one liquid-solid separator. In one embodiment of the invention, the liquid-solid separator can be operated at temperatures of between about 5 ° C and about 200 ° C. In yet another range, the liquid-solid separator can be operated from about 90 ° C to about 170 ° C. In yet another range, the liquid-solid separator can be operated from about 140 ° C to about 170 ° C.

ES 2 688 198 T3 ° C. The liquid-solid separator can be operated at pressures up to 200 psig. In yet another range, the solid liquid separator can be operated at pressures between about 30 psig and about 200 psig. The liquid-solid separator in the liquid displacement zone 40 may be operated in a continuous or batch mode, although it will be appreciated that for commercial processes, the continuous mode is preferred.

A portion of the oxidation by-products is displaced from liquid displacement zone 40 into a mother liquor and is removed through line 60. In one embodiment of the invention, additional solvent is fed to liquid displacement zone 40 through from line 50 to resuspend the crude carboxylic acid composition 30 and form a suspension composition 70. The mother liquor 60 is withdrawn from liquid travel zone 40 through line 60 and comprises a solvent, typically acetic acid, catalyst, and at least one oxidation by-product (s). The mother liquor in line 60 can either be sent to a process to remove impurities from the oxidation solvent through lines not shown or recycled to the catalyst system through lines not shown. One technique for removing impurities from mother liquor commonly used in the chemical processing industry is to switch or "purge" a portion of the recycle stream. Typically, the purge stream is simply discarded, or if economically justified, undergoes various treatments to remove unwanted impurities while recovering valuable components. Examples of impurity removal procedures include US Pat. No. 4,939,297 and US Patent No. 4,356,319.

In embodiments of the invention, a process is described that can allow the controlled partitioning of at least one compound, by-product, or impurity selected from the filtration mother liquor, the wash feed, and the terephthalic acid wet cake while achieving recovery. of the oxidation catalyst and solvent or oxidation reaction medium. The purge procedure can be significantly reduced or eliminated by enriching a post-catalyst removal composition 200 with selected compounds. The enrichment procedure results in these compounds being transported with the enriched composition 240 or the dry carboxylic acid composition 280, thereby greatly reducing or eliminating a purge procedure. The enrichment can be preceded by a catalyst removal procedure.

It should be noted that the liquid displacement zone 40 is optional and can also be located at multiple locations in the process as shown in Figure 2 by dashed lines. In another embodiment of the invention, there is more than one liquid displacement zone (s) 40 such as, for example, between the primary oxidation zone 20 and the step oxidation zone 80, and another liquid displacement zone may be located. liquid 40 after stepped oxidation zone 80 ° after crystallization zone 120. There could be three liquid displacement zones 40 as shown in Figure 2 or any combination as shown in Figure 2.

Step (c) optionally comprises oxidizing the suspension composition 70 or a crude carboxylic acid composition 30 in a step oxidation zone 80 to form a step oxidation composition 110.

In one embodiment of the invention, suspension composition 70 or a crude carboxylic acid composition 30 is withdrawn through line 70 to a stepped oxidation zone 80 and can be heated to between about 140 ° C to about 280 ° C. , another range is between about 160 ° C and about 240 ° C, another range is between about 170 ° C and about 200 ° C, and is further oxidized with air fed through line 106 to produce a step oxidation composition 110. Another range is from about 180 ° C to about 280 ° C.

Step oxidation zone 80 comprises at least one step oxidation reactor vessel. Suspension composition 70 is fed to step oxidation zone 80. The term "stepped" means that oxidation occurs in both primary oxidation zone 20 discussed above and step oxidation zone 80. For example, zone oxidation step 80 may comprise serial step oxidation reactor vessels.

When the carboxylic acid is terephthalic acid, the stepped oxidation zone 80 comprises an oxidation reactor that can be heated to between about 140 ° C and about 280 ° C or between about 160 ° C and about 240, or between about 170 ° C. and about 200 ° C, or

ES 2 688 198 T3 between about 160 ° C and about 210 ° C, and is further oxidized with air or a source of molecular oxygen fed through line 106 to produce a stepped oxidation composition 110. In one embodiment of the invention, oxidation in step oxidation zone 80 is at a higher temperature than oxidation in primary oxidation zone 20 to enhance removal of impurities. Step oxidation zone 80, as well as streams 30 and 70, can be heated directly with solvent vapor, or steam, or indirectly by any means known in the art. Purification in step oxidation zone 80 occurs by a mechanism involving recrystallization or crystal growth and oxidation of impurities.

Additional molecular oxygen or air may be fed through conduit 106 to step oxidation zone 80 in an amount necessary to oxidize at least a portion of the partially oxidized products, such as, 4-carboxybenzaldehyde (4-CBA) and p-acid. -toluic in the crude carboxylic acid composition 30 or the suspension composition 70 in the corresponding carboxylic acid. Generally, at least 70% by weight of 4-CBA is converted to terephthalic acid in step oxidation zone 80. Preferably, at least 80% by weight of 4-CBA is converted to terephthalic acid in step oxidation zone 80. The significant concentrations of 4-carboxybenzaldehyde and p-toluic acid in the terephthalic acid product are particularly detrimental to polymerization processes as they can act as chain terminators during the condensation reaction between terephthalic acid and ethylene glycol in the production of polyethylene terephthalate (PET).

Impurities in crude carboxylic acid composition 30 or suspension composition 70 go into solution when the terephthalic acid particles dissolve and recrystallize in step oxidation zone 80. Residual gas is removed from step oxidation zone 80 and can be fed to a recovery system where the solvent is removed from the waste gas comprising volatile organic compounds (VOCs). VOCs that include methyl bromide can be treated, for example, by incineration in a catalytic oxidation unit. Waste gas can also be processed before step oxidation composition 110 from step oxidation zone 80 is withdrawn through line 110.

Step (d) optionally comprises crystallizing suspension composition 70 or crude carboxylic acid composition 30 or step oxidation composition 110 in a crystallization zone 120 to form a crystallization suspension composition 160. Generally, crystallization zone 120 it comprises at least one crystallizer. The vapor product from crystallization zone 120 can be condensed in at least one condenser and returned to crystallization zone 120. Optionally, the condenser liquid or vapor product from crystallization zone 120 can be recycled, or it can be withdrawn or sent to an energy recovery device.

Furthermore, the off-gas from the crystallizer is removed and can be routed to a recovery system where the solvent is removed, and the off-gas from the crystallizer comprising VOCs can be treated, for example, by incineration in a catalytic oxidation unit.

Step oxidation composition 110 from step oxidation zone 80 is drawn through line 110 and fed to crystallization zone 120 comprising at least one crystallizer where it is cooled to a temperature of between about 110 ° C and about 190 ° C to form a crystallized suspension composition 160, preferably at a temperature of between about 140 ° C and about 180 ° C, and most preferably about 150 ° C and about 170 ° C.

Crystallized suspension composition 160 from crystallization zone 120 is drawn through line 160. Typically, crystallized suspension composition 160 is then fed directly into a beaker and cooled to form a chilled carboxylic acid composition 170. When the carboxylic acid is terephthalic acid, the cooled carboxylic acid composition 170 is cooled in a glass typically to a temperature of about 160 ° C or less, preferably about 100 ° C or less, before being introduced into a process to recover the terephthalic acid as a dry powder or a wet cake.

Step (e) optionally comprises cooling the crystallized suspension composition 160 or the step oxidation composition 110 or the suspension composition 70 or the crude carboxylic acid composition 30 in a cooling zone 165 to form a cooled carboxylic acid composition 170.

The crystallized suspension composition 160 or the step oxidation composition 110 or the composition of

ES 2 688 198 T3 suspension 70 or crude carboxylic acid composition 30 is fed to a cooling zone 165 and cooled to a temperature ranging from about 5 ° C to about 160 ° C, or from about 5 ° C to about 90 ° C, or between about 5 ° C and about 195 ° C or between about 20 ° C and about 160 ° C to form the cooled carboxylic acid composition 170. In another embodiment of the invention, the crystallized suspension composition 160 or the step oxidation composition 110 or the suspension composition 70 or the crude carboxylic acid composition 30 is fed to a cooling zone 165 and cooled to a temperature ranging from 20 ° C and about 90 ° C to form the chilled carboxylic acid composition 170. In another embodiment, the crystallized suspension composition 160 ° the step oxidation composition 110 or the suspension composition 70 or the crude carboxylic acid composition 30 is fed to a cooling zone 165 and cooled to a temperature ranging from about 20 ° C and about 120 ° C to form the cooled carboxylic acid composition 170. In another embodiment, crystallized suspension composition 160 or step oxidation composition 110 or suspension composition 70 or crude carboxylic acid composition 30 is fed to a cooling zone 165 and cooled to a temperature ranging from about 10 ° C and about 90 ° C to form the chilled carboxylic acid composition 170. In another embodiment, crystallized slurry composition 160 or step oxidation composition 110 or slurry composition 70 or crude carboxylic acid composition 30 is fed to a cooling zone 165 and cooled to a temperature ranging from about 20 ° C and about 60 ° C to form the chilled carboxylic acid composition 170. In another embodiment, crystallized slurry composition 160 or step oxidation composition 110 or slurry composition 70 or crude carboxylic acid composition 30 is fed to a cooling zone 165 and cooled to a temperature ranging from about 20 ° C and about 40 ° C to form the chilled carboxylic acid composition 170.

In another embodiment of the invention, a portion of the solvent is optionally removed from the crystallized suspension composition 160 or the step oxidation composition 110 or the suspension composition 70 or the crude carboxylic acid composition 30 through conduit 163 to produce the chilled carboxylic acid composition 170. In one embodiment of the invention, a portion can mean any part up to and including the whole. One portion can mean that at least 5% by weight of the solvent is removed. In another embodiment of the invention, a portion can mean that at least 10% by weight of the solvent is removed. In another embodiment of the invention, a portion can mean that at least 25% by weight of the solvent is removed. In another embodiment of the invention, a portion can mean that at least 50% by weight of the solvent is removed. In another embodiment of the invention, a portion can mean that at least 75% by weight of the solvent is removed. In another embodiment of the invention, a portion can mean that at least 85% by weight of the solvent is removed. In another embodiment of the invention, a portion can mean that at least 90% by weight of the solvent is removed from the crystallized suspension composition 160 or the step oxidation composition 110 or the suspension composition 70 or the crude carboxylic acid composition. 30.

Removal of the solvent can be accomplished by any means known in the art. For example, the solvent can be removed by evaporation or by flash evaporation and removal of the solvent in vacuo.

In another embodiment of the invention, both cooling and solvent removal are utilized.

Steps (a) through steps (d) and steps (a) through (e) are to illustrate embodiments in which a cooled carboxylic acid composition 170 is produced. It should also be noted that the liquid displacement zone 40 , step oxidation zone 80 and crystallization zone 120 were all optional in this embodiment. For example, other processes can be used that produce a cooled carboxylic acid composition 170, or a crystallized suspension composition 160, or a step oxidation composition 110, or a suspension composition 70, or a crude carboxylic acid composition 30. Such procedures are described in US Patents 5,877,346; 4,158,738; 5,840,965; 5,877,346; US 5,527,957; and US 5,175,355. Therefore, as shown in Figure 3, any method known in the art capable of producing a crystallized suspension composition 160 can be used. In addition, as shown in Figure 4, any method known in the art can be used. capable of producing a crude carboxylic acid composition 30 or a suspension composition 70.

Generally, as depicted in Figure 5, any 214 carboxylic acid composition can be used in step (f) as long as the carboxylic acid composition or the cooled carboxylic acid composition 170

ES 2 688 198 T3 comprises at least one carboxylic acid, at least one solvent and at least one catalyst. The carboxylic acid comprises any previously disclosed carboxylic acid or any carboxylic acid capable of being produced by the oxidation of the previously disclosed oxidizable compounds. The solvent is typically acetic acid, but can be any solvent disclosed above. The catalyst is any catalyst that has been previously disclosed. Figure 6 shows a process using a cooled carboxylic acid composition 170 in step (f).

Step (f) comprises contacting a cooled carboxylic acid composition 170, or a crystallized suspension composition 160, or a step oxidation composition 110 or a suspension composition 70, or a crude carboxylic acid composition 30 with a feed. wash 175 and optionally an enrichment feed 220 in a catalyst removal zone 180 to form a catalyst rich water 185, a wash water stream 62, an optional depleted enrichment water stream 230 and a post-catalyst removal composition 200.

The cooled carboxylic acid composition 170, or a crystallized suspension composition 160, or a step oxidation composition 110 or a suspension composition 70, or a crude carboxylic acid composition 30 is contacted with a wash feed 175 in the catalyst removal zone 180. In one embodiment, the cooled carboxylic acid composition 170 may be in the form of a dry powder, a wet cake, a liquid or gas entrained liquid, a solid, a suspension, a solution, or a combination thereof.

The wash feed 175 is contacted with the cooled carboxylic acid composition 170, or a crystallized suspension composition 160, or a step oxidation composition 110 or a suspension composition 70, or a crude carboxylic acid composition 30 in the catalyst removal zone 180 to remove a portion of the catalyst from the purified cooled carboxylic acid composition 170 to form the post-catalyst removal composition 200. In one embodiment, the postcatalyst removal composition 200 comprises a carboxylic acid, a solvent, a catalyst, and optionally one or more compounds selected from the group consisting of isophthalic acid, phthalic acid, trimellitic acid, acid isomers. hydroxymethylbenzoic, hydroxybenzoic acid isomers, benzoic acid and toluic acid isomers. In another embodiment of the invention, postcatalyst removal composition 200 comprises a carboxylic acid, a solvent, and optionally one or more compounds selected from the group consisting of isophthalic acid, phthalic acid, trimellitic acid, benzoic acid, acid 4-hydroxybenzoic, 4-hydroxymethylbenzoic acid, 4,4'-dicarboxybiphenyl, 2,6-dicarboxyanthraquinone, 4,4'-dicarboxystilbene, 2,5,4'-tricarboxybiphenyl, 2,5,4'-tricarboxybenzophenone, 4,4'-dicarboxybenzophenone, 4,4'-dicarboxybenzyl, form-acet-hydroxybenzoic acid, acethhydroxymethylbenzoic acid, α-bromo-p-toluic acid, bromo-benzoic acid, bromo-acetic acid, p-tolualdehyde and terephthaldehyde. In one embodiment of the invention, postcatalyst removal composition 200 may be in the form of a dry powder, a wet cake, a suspension, a solution, a liquid, a liquid, or a gas entrained solid. In another embodiment of the invention, the postcatalyst removal composition 200 may comprise any composition suitable for producing the dry carboxylic acid composition 280 which will be described later.

A portion of the catalyst is removed through the catalyst rich water 185 and the wash water 62 of the cooled carboxylic acid composition 170, or a crystallized suspension composition 160, or a step oxidation composition 110 or a suspension composition 70 , or a crude carboxylic acid composition 30 to produce the post-catalyst removal composition 200 having a catalyst concentration of less than 1000 ppm by weight. Catalyst Rich Water 185 comprises solvent, catalyst, and oxidation by-product (s). The wash water 62 comprises at least one solvent, at least one catalyst, and at least one oxidation by-product (s). As used in this invention, the catalyst can be at least one catalyst described above in the catalyst system. In another embodiment, the catalyst can be any catalyst used in an oxidation reaction of an aromatic raw material. In another embodiment of the invention, a catalyst portion is removed when the post-catalyst removal composition 200 has a catalyst concentration of less than 500 ppm by weight. In another embodiment of the invention, a portion is the amount of catalyst that is removed such that the post-catalyst removal composition 200 has a catalyst concentration of less than 250 ppm by weight. In another embodiment of the invention, a portion is the amount of catalyst that is removed such that the post-catalyst removal composition 200 has a catalyst concentration of less than 75 ppm by weight. Another range is less than 50 ppm by weight. In still other ranges, the catalyst concentration of the

ES 2 688 198 T3 postcatalyst removal 200 is less than 20 ppm by weight or less than 10 ppm by weight. In still other ranges, the catalyst concentration is less than 5 ppm by weight or less than 1 ppm by weight. As used in this invention, "catalyst concentration" means the total concentration of all the catalyst in the composition.

The wash feed 175 comprises compositions that are capable of producing the above-disclosed postcatalyst removal composition 200. In one embodiment of the invention, the wash feed 175 may be in the form of a condensable liquid or vapor or a solution. In another embodiment of the invention, the wash feed 175 is greater than 50% by weight of water. In another embodiment of the invention, the wash feed 175 is greater than 75% by weight of water. In another embodiment of the invention, the wash feed 175 is greater than 90% by weight of water. In another embodiment of the invention, the wash feed 175 is greater than 50% by weight solvent. In another embodiment of the invention, the wash feed 175 is greater than 75% by weight solvent. In another embodiment of the invention, the wash feed 175 is greater than 90% by weight solvent. In another embodiment of the invention, the wash feed 175 comprises at least one solvent, and optionally at least one compound selected from the group consisting of benzoic acid, isophthalic acid, phthalic acid, trimellitic acid, hydroxybenzoic acid isomers, isomers of hydroxymethylbenzoic acid and p-toluic acid. In another embodiment of the invention, the wash feed 175 comprises compositions sufficient to produce the dry carboxylic acid composition 280 disclosed below. In another embodiment of the invention, the wash feed 175 comprises at least one solvent, and optionally at least one compound selected from the group consisting of isophthalic acid, phthalic acid, trimellitic acid, hydroxymethylbenzoic acid isomers, hydroxybenzoic acid isomers , benzoic acid, and isomers of toluic acid and where at least one of the compounds is enriched above the concentration of the post-catalyst removal composition 200. In another embodiment, the wash feed 175 comprises at least one solvent, and optionally one or more compounds selected from the group consisting of isophthalic acid, phthalic acid, trimellitic acid, benzoic acid, 4-hydroxybenzoic acid, 4-hydroxymethylbenzoic acid, 4 , 4'-dicarboxybiphenyl, 2,6-dicarboxyanthraquinone, 4,4'-dicarboxystilbene, 2,5,4'-tricarboxybiphenyl, 2,5,4'-tricarboxybenzophenone, 4,4'-dicarboxybenzophenone, 4,4'-dicarboxybenzyl, form-acethhydroxybenzoic acid, acet-hydroxymethylbenzoic acid, α-bromo-p-toluic acid, bromo-benzoic acid, bromoacetic acid, p-tolualdehyde and terephthaldehyde.

In one embodiment of the invention, the wash feed has a temperature ranging between the freezing point of the solvent and about 90 ° C, or about 5 ° C and about 90 ° C, or about 5 ° C and about 195 ° C. , or about 5 ° C and about 100 ° C or the freezing point of the solvent and about 70 ° C, or about 5 ° C and about 70 ° C, or about 30 ° C and about 70 ° C, or the freezing point of the solvent and about 30 ° C.

In one embodiment of the invention, the wash ratio ranges from about 0.2 to about 6.0, or about 0.2 and about 4.0, or about 0.2 and about 1.0, or about 0.4 and about 1, or about 0.5 and about 2.0, or about 1 and about 3. The "wash ratio" as used in this invention means the total mass of the wash feed 175 divided by the mass of the post-catalyst removal composition 200 on a dry solids basis.

The catalyst removal zone 180 comprises at least one solid liquid separation device capable of contacting the cooled carboxylic acid composition 170 or a crystallized suspension composition 160, or a step oxidation composition 110 or a suspension composition 70 , or a crude carboxylic acid composition 30 with the wash feed 175 to produce a post-catalyst removal composition 200.

For example, catalyst removal zone 180 comprises a solid liquid separator in which a subsequent catalyst removal composition 200 is generated and then washed with a wash solvent. Examples include, but are not limited to, a vacuum rotary drum filter, a vacuum belt filter, a rotary pressure filter, a filter press, and a pressure leaf filter. Solid liquid separation devices, which can generate a cake but do not allow washing, are also useful when combined with a resuspension device. Solid liquid separation devices, such as a solid bowl centrifuge, can be used to generate a cake that can be resuspended with wash solvent in a

ES 2 688 198 T3 separate mixing device to achieve dilution washing. Dilution washing often requires multiple stages of cake generation and subsequent resuspension that are operated in a countercurrent manner.

Step (g) optionally comprises contacting a post-catalyst removal composition 200 with an enrichment feed 220 in an enrichment zone 210 to form a depleted enrichment stream 230 and an enriched composition 240; wherein the enriched composition 240 comprises one or more compounds selected from the group consisting of isophthalic acid, phthalic acid, trimellitic acid, isomers of hydroxymethylbenzoic acid, isomers of hydroxybenzoic acid, benzoic acid, and isomers of toluic acid and where at least one of The compounds are enriched above the concentration of the post-catalyst removal composition 200. In another embodiment of the invention, the enriched composition 240 comprises one or more compounds selected from the group consisting of isophthalic acid, phthalic acid, trimellitic acid, benzoic acid, 4-hydroxybenzoic acid, 4-hydroxymethylbenzoic acid, 4,4 ' dicarboxybiphenyl, 2,6-dicarboxyanthraquinone, 4,4'-dicarboxystilbene, 2,5,4'-tricarboxybiphenyl, 2,5,4'-tricarboxybenzophenone, 4,4'-dicarboxybenzophenone, 4,4'-dicarboxybenzyl, form-acet acid -hydroxybenzoic, Acethhydroxymethylbenzoic acid, α-bromo-p-toluic acid, bromo-benzoic acid, bromo-acetic acid, p-tolualdehyde and terephthaldehyde.

The term "enriched" means that the primary outlet stream leaving an enrichment zone or plurality of enrichment zones, or any zone, or any transport mentioned in this invention has a higher concentration of any selected enrichment compound (s) ( s) than the primary inlet stream entering an enrichment zone or plurality of enrichment zones. According to claim 1, the enrichment compound (s) comprise (s) at least one compound or compounds selected from the group consisting of terephthalic acid, isophthalic acid, phthalic acid, benzenetricarboxylic acid isomers, acid benzoic, hydroxybenzoic acid isomers, hydroxymethylbenzoic acid isomers, dicarboxybiphenyl isomers, dicarboxystilbene isomers, tricarboxybiphenyl isomers, tricarboxybenzophenone isomers, dicarboxybenzophenone isomers, dicarboxybenzyl isomers, formacet-hydroxybenzoic acid isomers, acet-hydroxymethylbenzoic acid isomers, α-bromo-p-toluic acid isomers, bromo-benzoic acid, bromo-acetic acid, phthalodehydehyde isomers and phthalodehyde isomers . In another embodiment of the invention, the enrichment compounds or enrichment feed 220 may also include monomers, comonomers, additives, or any compound useful for making polyester or any combination thereof. For example, in one embodiment depicted in Figure 1a and 1b, the primary outlet stream is the enriched composition 240 and the primary inlet stream is the post-catalyst removal composition 200. In one embodiment, shown in Figure 9, the primary inlet stream is carboxylic acid composition 214, or crystallized suspension composition 160, and the primary outlet stream is enriched carboxylic acid stream 280. In a In the embodiment, which is depicted in Figure 10, the primary input stream is the carboxylic acid composition 214, and the primary output stream is the enriched carboxylic acid composition 216.

In other embodiments of the invention, the term "enriched" means that the primary outlet stream has a higher concentration of any selected compound (s) as described above by at least 5 ppmw, or at least 10 ppmw, or at least 100 ppm, or at least 1000 ppm, or at least 5% by weight, or at least 10% by weight, or at least 25% by weight, or at least 30% by weight or at least 50% by weight than the primary input current, all measured on a dry solid basis.

Enrichment feed 220 comprises compounds sufficient to enrich at least one compound selected from the group consisting of terephthalic acid, isophthalic acid, phthalic acid, isomers of benzenetricarboxylic acid, benzoic acid, isomers of hydroxybenzoic acid, isomers of hydroxymethylbenzoic acid, isomers of dicarboxybiphenyl, dicarboxybiphenyl isomers, tricarboxybiphenyl isomers, tricarboxybenzophenone isomers, isomers of dicarboxybenzophenone, isomers of dicarboxybenzyl, isomers of formacet-hydroxybenzoic acid, isomers of acet-hydroxymethylbenzoic acid, isomers of α-bromo-toluic acid, bromo-benzoic acid, bromo-acetic acid, isomers of tolomers, benzoyl alcohol, iscillic isomers of methylbenzyl alcohol, and isomers of phthaldehyde. In the other embodiment of the invention, enrichment feed 220 may also include monomers, comonomers, additives, or any compound useful for making polyester or any combination thereof. In another embodiment of the invention, the enrichment compounds or enrichment feed 220 comprises one or more compounds selected from the group consisting of isomers of fluorene, isomers of diphenylmethane, isomers of diphenylethane, and isomers

ES 2 688 198 T3 saturated aromatics. Examples of saturated aromatic isomers include, but are not limited to, cyclohexanecarboxylic acid and 1,4-cyclohexanedicarboxylic acid.

In another embodiment of the invention, enrichment feed 220 comprises sufficient compounds to enrich post-catalyst removal composition 200 as shown in Figure 7 such that on a dry solids basis the enriched composition 240 comprises identical compositions as dry carboxylic acid composition 280 described below. There are no special limitations as to the conditions of the enrichment feed 220 other than that it comprises compounds sufficient to enrich the post-catalyst removal composition 200 with the enrichment compound (s) specified above. For example, enrichment feed 220 may be, but is not limited to, a cake, powder, solids, wash feed, suspension, solution, paste, or gas entrained solid or liquid.

It should be noted that enrichment feed 220 does not necessarily have to be introduced into enrichment zone 210. As shown in Figure 8, enrichment feed 220 can be introduced at various locations, including, but not limited to, enrichment zone 210, dewatering zone 250, drying zone 270, and in polyester processes, or more specifically PET processes. A variety of polyester processes have been developed. Early efforts used reactive distillation as shown in US Patent No. 2,905,707 and reactive steam distillation of ethylene glycol ("EG") as reagents as shown in US Patent No. 2,829,153 to produce PET. Multiple vessels with stirring have been disclosed for additional reaction control as shown in the US patent. No. 4,110,316, US Patent No. 3,054,776 discloses the use of lower pressure drops between reactors in a PET process, while US Patent No. 3,385 .881 discloses multiple reactor stages within a reactor shell. These designs were improved to solve problems with entrainment or plugging, thermal integration, heat transfer, reaction time, number of reactors, etc., as described in US Pat. US Nos. 3,118,843; 3,582,244; 3,600,137; 3,644,096; 3,689,461; 3,819,585; 4,235,844; 4,230,818; and 4,289,895.

In a PET process 400 as shown in Figure 8, enrichment feed 220 can be introduced into the pulp tank, esterification reactors, and / or other locations in the process. The enrichment feed 220 can be introduced at multiple sites or at a single site, either all at once or gradually over time.

Raw materials for the manufacture of staged growth polymers and copolymers from terephthalic acid (TPA) include monomers and comonomers, catalyst (s), and additives. Monomers and comonomers include, but are not limited to, diamines, diols, and diacids, etc. Important commercial stage growth polymers that can be prepared using tPa as the monomer or comonomer include polyamides, polyesters, especially polyethylene terephthalate (PET), co-polyamides, copolyesters, and copolyester-amides. It may be advantageous to introduce and achieve an intimate mixture of the monomers or comonomers, catalyst (s) and / or additives with the terephthalic acid, so that they do not have to be added to the polymerization process separately from the TPA. A process has been invented that allows the production of terephthalic acid, in the form of a powder, paste, wet cake, or suspension, and which is enriched with certain monomers or comonomers, catalyst (s) and / or additives. This procedure is accomplished with intimate mixing with TPA to avoid the need for a separate addition of materials in the PET manufacturing process.

The following description will be provided for PET, but it can be extended directly to other polymers and copolymers for growth in stages made using TPA. The manufacture of PET involves the esterification of terephthalic acid with ethylene glycol, the formation of a prepolymer, and the polycondensation to form PET with a sufficiently high molecular weight for further processing and intended application of the polymer, which may include coatings, fibers, films, containers. and other items. Certain monomers or comonomers, catalyst (s) and / or additives can also be used. The most common comonomers, in addition to ethylene glycol (EG), are isophthalic acid (IPA or PIA) and cyclohexanedimethanol (CHDM). The most common catalysts for the manufacture of PET are antimony and titanium. Useful additives in the manufacture of PET include, but are not limited to, phosphorus compounds, dyes, pigments, colorants, reheating agents, polydispersity modifiers, antioxidants and stabilizers (thermal, oxidative, UV, etc.), coupling agents. or chain extenders, end-protecting agents, telechelic modifiers, such as, for example, metal-coordinated sulfo-isophthalic acid, acetaldehyde reducing agents, acetaldehyde scavengers,

ES 2 688 198 T3 buffers, agents to reduce the formation of diethylene glycol (DEG), antistatics, antislip or antiblocking agents, barrier modifiers, nucleators, titanium dioxide and other fillers / opacifiers, antifog agents, optical brighteners, etc. The introduction of such comonomers, catalyst (s) and / or additives is typically at various points in the PET manufacturing process separate from the addition of TPA. However, it may be advantageous to introduce certain additives with the TPA, ie before the PET manufacturing process, especially comonomers, such as isophthalic acid and dyes or colorants that are thermally stable. Thus, the comonomers, catalyst (s), and additives can be introduced and intimately mixed with the TPA during the TPA manufacturing process rather than during the PET manufacturing process. Specific TPA manufacturing steps in which intimate additive introduction can be achieved include addition to the solid liquid separation device to isolate the TPA cake, in any drying equipment, to or in any conveyor line or process tubing. , and before shipment of the TPA product in any container. Therefore, the TPA product in any form, whether they are dry solids (with waste water or acetic acid), wet cake (with a little liquid water, or methanol, or EG, or some other diol or comonomer, or mixtures) , wet paste (with a little liquid water, or methanol, or EG, or some other diol or comonomer, or mixtures), or suspension (with water, or methanol, or eG, or some other diol or comonomer, or mixtures) can be enriched prior to use in the manufacture of PET.

In addition, Figure 9 depicts that enrichment feed 220 can be introduced and enrichment can occur at any point from crystallized suspension composition 160 to dry carboxylic acid composition 280.

Another embodiment is provided in Figure 10. The enrichment procedure can be carried out on a carboxylic acid composition 214 in an extended enrichment zone 213 to produce an enriched carboxylic acid composition 216. The enrichment feed 220 can comprise any composition previously or subsequently disclosed. There are no limitations on the carboxylic acid composition other than that the carboxylic acid composition 214 comprises a carboxylic acid, an optional solvent, and optionally a catalyst. In another embodiment, the carboxylic acid composition can be used to produce the dry carboxylic acid composition 280.

It should also be noted that in another embodiment of the invention, the enrichment zone 210 and the catalyst removal zone 180 can be combined into one zone comprising at least one device that fulfills both functions as shown in Figure 11.

There are no special limitations to the enrichment feed 220 other than it has a suitable composition to enrich the post-catalyst removal composition 200. For example, the enrichment feed 220 can be a solid, a wash, a slurry, a paste. , solids, a solution or a liquid or solid entrained by gas. In one embodiment of the invention, enrichment feed 220 comprises compositions capable of preparing carboxylic acid dry cake composition 280. In another embodiment, enrichment feed 220 is solids only and is added at one point or throughout the process. to produce carboxylic acid dry cake composition 280.

Figures 12, 13, 14 and 15 illustrate an embodiment showing how enrichment feed 220 can be obtained and how enrichment feed 220 is utilized throughout the process. In Figures 12, 13, 14 and 15, the enrichment feed (s) are depicted as stream 220. This is to illustrate that the enrichment feed (s) 220 can be taken from a variety of sources or one source and the enrichment feed (s) can have a variety of different, different compositions. physical forms and different addition points in the procedure. In addition, the enrichment feed 220 can be added all at once, intermittently, or gradually throughout the procedure.

Figure 15 illustrates one embodiment of how an enrichment feed 220 can be obtained. At least a portion of the catalyst-rich water 185 is fed to a cooling and / or concentration zone 300 to generate a concentrated stream of mother liquor 310 and a solvent stream 311. Sufficient solvent removal is achieved in the cooling and / or concentration zone 300 so that the concentrated catalyst-rich stream 310 can have% solids ranging from 10% by weight to 45% by weight.

A portion of the concentrated mother liquor stream 310 and an extraction solvent stream 323 are fed to an extraction zone 320 to generate a catalyst-rich stream 324 and a stream of

ES 2 688 198 T3 depleted catalyst 350. The equilibrium of the concentrated mother liquor stream 310 and a wash stream 331 is fed to a liquid-solid separation zone (SLS zone), generating a wet cake stream 340 and a stream of wash water 332, comprising mother liquor and wash water. The wet cake stream 340 can be used as an enrichment feed 220 and a portion of the wet cake stream 340 can be sent to the product filter or product drier to enrich the product stream with at least a portion of the content of the stream. wet cake 340. Alternatively, a portion of the wet cake stream 340 and a portion of the catalyst lean stream 350 can be fed to an optional mixing zone where the two streams are mixed to form an enrichment feed 220 and a portion of this stream can be sent to a product filter or product drier to enrich the product stream with at least a portion of the content of enrichment feed 220.

The extraction zone 320 comprises at least one extractor. The extraction solvent 323 used in the extractor should be substantially insoluble in water to minimize the amount of organic solvent dissolved in the aqueous fraction. In addition, the extraction solvent 323 is preferably an azeotropic agent that serves to aid in the recovery of the solvent from the organic extract. Solvents that have proven particularly useful are C1 to C6 alkyl acetates, particularly n-propyl acetate (n-PA), isopropyl acetate, isobutyl acetate, sec-butyl acetate, ethyl acetate, and n-acetate. butyl, although other water-insoluble organic solvents having a suitable density and a sufficiently low boiling point, such as p-xylene, can also be used. N-propyl acetate and isopropyl acetate are particularly preferred because of their relatively low water solubility, excellent azeotropic behavior, and their ability to remove remaining acetic acid as well as high-boiling organic impurities from the aqueous mixture.

Extraction can be performed using solvent ratios of from about 1 to about 4 parts by weight of solvent per part of the extractor feed, depending on the extractor feed composition. The spatial velocities of the combined feeds to the extractor generally range from 1 to about 3 h^-1. Although the extraction can be carried out at room temperature and pressure, the solvent and extractor can be heated from about 30 ° C to about 70 ° C, or from about 40 ° C to about 60 ° C.

Another embodiment is shown in Figure 24 and illustrates another procedure for obtaining an enrichment feed. At least a portion of the solvent rich stream 900 is fed to a solids concentration zone 910 to generate a concentrated solvent rich stream 920. The solids concentration zone 910 has no limitations other than that the solids content of the concentrated solvent rich stream 920 is greater than that of the solid rich stream 900 in weight percent. Solid concentration zone 910 can enrich solids by cooling, evaporation, direct solvent removal, or any other means known in the art. For example, concentrated solids zone 910 may comprise at least one evaporator. In one embodiment of the invention, solvent rich stream 900 comprises at least one solvent, at least one carboxylic acid, and at least one oxidation by-product. In one embodiment of the invention, solid enrichment is achieved such that the solvent-rich concentrated stream 920 can have% solids ranging from about 0.5% by weight to about 45% by weight or about 1% by weight. weight and about 30% by weight, or about 5% by weight and about 30% by weight, or about 1% by weight and about 45% by weight.

The concentrated solvent-rich stream 920 is then sent to a concentrated liquid-solid separation zone (concentrated SLS zone) 930. The concentrated solvent-rich stream 920 is fed to the concentrated SLS zone 930 which generates a concentrated wet cake and a mother liquor stream 940. The concentrated wet cake can be used as an enrichment feed 220. The enrichment feed 220 can be sent to a product filter or product drier to enrich the TPA product stream. In another embodiment of the invention, enrichment feed 220 can be recycled back to a TPA production process at any time after the primary oxidation step or at any point previously mentioned in this disclosure. The concentrated SLS zone 930 comprises at least one solid liquid separator. Examples of solid liquid separation devices include, but are not limited to, a candle filter, a pressure filter, a rotary drum pressure filter, etc. According to claim 1, the separation device is a spark plug filter. Figure 23 shows the change in color b * versus the amount of plug filter material added. The plug filter material may be the enrichment feed 220 that is produced from the concentrated SLS zone 930 when the zone of

IS 2 688 198 T3

Concentrated SLS comprises at least one spark plug filter. Figure 22 shows that when approximately 0.5% by weight of the enrichment feed is added, an increase in b * of less than 1 is observed. Figure 22 also shows that when approximately 5% by weight of the enrichment feed, an increase in b * of less than 2 is observed. Extrapolation from the figure also shows that when about 10% by weight of the enrichment feed is added, an increase in b * of about 4 is observed. Extrapolation from the figure also shows that when about 20% is added in weight of the enrichment feed, an increase in b * of approximately 8 is observed.

Figures 12, 13 and 14 illustrate an embodiment showing how an enrichment feed 220 can be used throughout the procedure. Aromatic feedstock 10 comprising reagents and catalyst is fed to primary oxidation zone 20 generating a crude carboxylic acid composition 30. The crude carboxylic acid composition 30 and a solvent stream 50 are fed to the liquid displacement zone 40 to achieve partial solvent exchange by exchanging part of the oxidation solvent present in stream 30 with neat solvent that generates a solvent stream. displaced 60 and a stream of suspension composition 70. Suspension stream 70 and an oxygen-containing gas stream 106 are fed to a step oxidation zone 80 to generate a step oxidation composition 110. Step oxidation composition 110 and a solvent stream 101 are fed to a liquid displacement zone 100 to achieve partial solvent exchange by exchanging part of the oxidation solvent present in step oxidation composition 110 with pure solvent that generates a stream. of displaced solvent 102 and a subsequent solvent exchange step oxidation composition 115. Subsequent solvent exchange step oxidation composition 115 is fed to crystallization zone 120 generating a crystallized suspension composition 160, an optional solvent vapor stream 121, and an optional liquid solvent solvent stream 122. Crystallized slurry composition stream 160 and an optional enrichment feed 220 are fed to a cooling zone 165 where a cooled carboxylic acid stream 170 and an optional oxidation solvent stream 163 are generated. The cooled carboxylic acid composition 170, a wash feed 175, and an optional enrichment feed 220 are fed to a catalyst removal zone 180 to generate a post-catalyst removal composition 200, the catalyst-rich water 185, and a water wash 62, and a lean enrichment feed 230. Post-catalyst removal composition 200, exchange solvent stream 201, and optional enrichment feed 220 are fed to optional solvent exchange zone 205 to generate exchange solvent water 202 and solvent exchange composition. rear 206. The subsequent solvent exchange composition 206 and an enrichment feed 220 are fed to an enrichment zone 210 to generate an enriched carboxylic acid composition stream 240 and a depleted enrichment feed 230. The enriched composition 240 and an enrichment feed optional 220 are fed to an optional dehydration zone 250 to generate a dehydrated carboxylic acid composition 260.

The catalyst removal zone 180, the solvent exchange zone 205, the enrichment zone 210, the dehydration zone 250, and optionally the drying zone 270 can be achieved in a single solid liquid separation device, preferably a continuous pressure or a vacuum filter, and most preferably a vacuum belt filter. A continuous pressure drum filter or rotary vacuum filter can also be used. The dehydrated enriched carboxylic acid composition 260, and an optional enrichment feed 220 are fed to an optional drying zone 270 to generate a dry enriched carboxylic acid composition 280 and a solvent vapor stream 275.

In another embodiment, enrichment feed 220 comprises water in an amount greater than 50% by weight. In another embodiment of the invention, enrichment feed 220 comprises water in an amount greater than 75% by weight. In another embodiment of the invention, enrichment feed 220 comprises water in an amount greater than 95 % by weight. In another embodiment of the invention, enrichment feed 220 comprises water in an amount greater than 99% by weight.

In another embodiment of the invention, postcatalyst removal composition 200 enters enrichment zone 210 at a temperature in a range of about 200 ° C to the freezing point of enrichment zone 220. In another embodiment of the invention, post-catalyst removal composition 200 enters enrichment zone 210 at a temperature in a range of about 100 ° C to the freezing point of enrichment zone 220. In another embodiment of enrichment zone invention, postcatalyst removal composition 200 enters enrichment zone 210 at a temperature

ES 2 688 198 T3 in a range from about 200 ° C to about 0 ° C. In another embodiment of the invention, postcatalyst removal composition 200 enters enrichment zone 210 at a temperature in a range of about 0 ° C to 100 ° C. Other ranges are less than 100 ° C to 20 ° C; and from 40 ° C to less than 100 ° C.

The enrichment zone 210 comprises at least one device sufficient to provide a sufficient amount of contact time between the enrichment feed 220 and the subsequent catalyst removal composition 200 to allow at least one compound selected from the group consisting of benzoic acid, isophthalic acid, phthalic acid, trimellitic acid, isomers of hydroxybenzoic acid, Hydroxymethylbenzoic acid isomers and toluic acid isomers are enriched. In another embodiment of the invention, enrichment zone 210 or extended enrichment zone 213 comprises a device that provides a sufficient amount of contact time between the enrichment feed and the subsequent catalyst removal composition 200 or the acid composition. carboxylic acid 214 to allow monomers, comonomers, additives, and other compounds useful in the production of polyesters to be enriched. In another embodiment of the invention, the enrichment zone 210 or the extended enrichment zone 213 comprises at least one device selected from the group consisting of a belt filter, a pressure filter, a rotary pressure filter, centrifuges capable of of adding solids and / or a wash stream such as a perforated basket centrifuge, a disk stack centrifuge, etc., and the like.

In another embodiment of the invention, the enriched composition 240 on a dry solids basis encompasses all possible combinations of compositions of the dry carboxylic acid composition 280 described later in this disclosure. The dry solids base will be described below in this disclosure.

All compositions are measured on a dry solids basis which will be described later in the disclosure. All measurements and claims in ppm are in ppm by weight on a dry solids basis.

Step (h) comprises optionally dehydrating the enriched composition 240 in a dehydration zone 250 to form a dehydrated post-catalyst removal composition 260.

Dehydration can be carried out by any means known in the art. Dewatering results in the dehydrated postcatalyst removal composition 260 having a moisture content of less than 25% by weight moisture. Other moisture content ranges are less than 15% by weight moisture or less than 10% by weight moisture or less than 5% by weight moisture. In yet another embodiment of the invention, dehydration can be achieved by using primarily mechanical means for drying and where most of the drying is not carried out by evaporation. Most as used in this invention means more than 50%.

Step (i) comprises filtering and optionally drying the enriched composition 240 or the dehydrated post-catalyst removal composition 260 in a filtration and drying zone 270 to remove a portion of the solvent from the enriched composition 240 or the catalyst removal composition. further dehydrated 260 to produce dry carboxylic acid composition 280.

The enriched composition 240 or dehydrated postcatalyst removal composition 260 is withdrawn from enrichment zone 210 or dewatering zone 250 and fed to filtration and drying zone 270.

In one embodiment of the invention, the filter cake goes through an initial solvent removal step, then rinsed with an acid wash to remove residual catalyst, and then the solvent is removed again before being sent to the dryers.

Drying zone 270 comprises at least one dryer and can be accomplished by any means known in the art that is capable of evaporating at least 10% of the volatiles remaining in the filter cake to produce the dry carboxylic acid composition. 280. For example, indirect contact dryers, including a rotary steam tube dryer, a single-axis Porcupine® Processor dryer, and a Bepex Solidaire® processor can be used for drying to produce a dry 280 carboxylic acid composition. Direct contact dryers, including a fluid bed dryer and conveying line drying can be used for drying to produce a 280 dry carboxylic acid composition. In another embodiment, drying is

ES 2 688 198 T3 can be carried out in a solid liquid separation device such as a vacuum belt filter or a rotary pressure drum filter, allowing a gas stream to flow through the filter cake thus removing the volatile. In another embodiment of the invention, a liquid-solid separation device may comprise any combination of the following zones: a catalyst removal zone, an enrichment zone, a dewatering zone, and a drying zone. A dry carboxylic acid composition can be a carboxylic acid composition with less than 5% moisture, preferably less than 2% moisture, and more preferably less than 1% moisture, and even more preferably less than 0.5%, and even more preferably less than 0.1%.

In one embodiment of the invention, the dry carboxylic acid composition 280 has a b * of less than about 9.0. In another embodiment of the invention, the b * color of the carboxylic acid composition is 280 is less than about 6.0. In another embodiment of the invention, the b * color of the carboxylic acid composition is 280 is less than about 5.0. In another embodiment of the invention, the b * color of the carboxylic acid composition is 280 is less than about 4.0. In another embodiment of the invention, the b * color of the carboxylic acid composition is 280 is less than about 3. The b * color is one of the attributes of three colors measured on a reflectance-based spectroscopic instrument. A Hunter Ultrascan XE instrument in reflectance mode is typically the measurement device. Positive readings indicate the degree of yellow (or absorbance of blue), while negative readings indicate the degree of blue (or absorbance of yellow).

Compositions comprising at least one carboxylic acid

I. In one embodiment of the invention, dry carboxylic acid composition 280 comprises:

(1) carboxylic acid in an amount greater than 50 percent by weight, or greater than 60 percent by weight, or greater than 70 percent by weight, or greater than 80 percent by weight, or greater than 90 percent by weight, or greater than 95 percent by weight, or greater than 97 percent or greater than 98 percent or greater than 98.5 percent or greater than 99 percent, or greater than 99.5 percent by weight; and optionally (2) (a) carboxybenzaldehyde (CBA) isomers in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm and 125 ppm; or (b) isomers of toluic acid (TA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm; or (c) both of the following:

(i) carboxybenzaldehyde isomers in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

(ii) isomers of toluic acid in an amount ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

where the total concentration of carboxylbenzaldehyde and toluic acid isomers ranges between 1 ppm and 2000 ppm, 1 ppm and 1000 ppm, or between 1 ppm and 500 ppm, or between 1 ppm and 250 ppm, or between 1 ppm and 125 ppm; and (3) at least one, or at least two, or at least three, or at least four, or at least five, or at least six, or at least seven, or at least eight, or at least nine, or at least at least ten, or at least eleven, or at least twelve, or at least thirteen, or at least fourteen, or at least fifteen, or at least sixteen, or at least seventeen, or at least eighteen, or at least nineteen, or at least minus twenty, or all of the following:

(a) Terephthalic acid in an amount of at least 50 ppm, or ranging from 50 ppm to 2000 ppm, or ranging from 75 ppm to 1500 ppm, or ranging from 100 ppm to 1000 ppm, or ranging from 150 ppm or 500 ppm;

(b) isophthalic acid in an amount of at least 50 ppm, or ranging from 50 ppm to 2000 ppm, or ranging from 75 ppm to 1500 ppm, or ranging from 100 ppm to 1000 ppm, or ranging from 150 ppm and 500 ppm;

ES 2 688 198 T3 (c) phthalic acid in an amount of at least 20 ppm, or at least 50 ppm, or at least 100 ppm, or ranging from 20 ppm to 1000 ppm, or ranging from 50 ppm to 750 ppm , or ranging from 100 ppm to 500 ppm;

(d) isomers of benzenetricarboxylic acid in an amount of at least 125 ppm, or ranging from 125 ppm to 1000 ppm, or ranging from 150 ppm to 750 ppm, or ranging from 175 ppm to 500 ppm;

(e) Benzoic acid in an amount of at least 50 ppm, or at least 75 ppm, or at least 100 ppm, or ranging from 50 ppm to 500 ppm, or ranging from 75 ppm to 400 ppm, or ranging from 100 ppm and 300 ppm;

(f) isomers of hydroxybenzoic acid in an amount of at least 3 ppm, at least 5 ppm, or at least 20 ppm, or ranging from 3 ppm to 200 ppm, or ranging from 5 ppm to 175 ppm, or ranging between 20 ppm and 150 ppm;

(g) isomers of hydroxymethylbenzoic acid in an amount of at least 40 ppm, or at least 80 ppm, or at least 100 ppm, or ranging from 40 ppm to 200 ppm, or ranging from 80 ppm to 180 ppm, or ranges from 100 ppm to 160 ppm;

(h) isomers of dicarboxybiphenyl in an amount ranging from 20 ppm to 150 ppm, or ranging from 25 ppm to 100 ppm, or ranging from 25 ppm to 75 ppm;

(i) isomers of dicarboxystilbene in an amount ranging from more than 7 ppm; or more than 10 ppm;

(j) isomers of tricarboxybiphenyl in an amount ranging from 8 ppm to 100 ppm, or ranging from 9 ppm to 50 ppm, or ranging from 10 ppm to 25 ppm;

(k) isomers of tricarboxybenzophenone in an amount ranging from 5 ppm to 100 ppm, or ranging from 6 ppm to 75 ppm, or ranging from 7 ppm to 60 ppm;

(l) isomers of dicarboxybenzophenone in an amount ranging from 10 ppm to 150 ppm, or ranging from 12 ppm to 100 ppm, or ranging from 15 ppm to 75 ppm;

(m) isomers of dicarboxybenzyl in an amount ranging from 1 ppm to 30 ppm, or ranging from 2 ppm to 20 ppm, or ranging from 3 ppm to 10 ppm;

(n) isomers of form-acet-hydroxybenzoic acid in an amount ranging from 1 ppm to 20 ppm, or ranging from 2 ppm to 15 ppm, or ranging from 3 ppm to 10 ppm;

(o) isomers of acet-hydroxymethylbenzoic acid in an amount ranging from 1 ppm to 30 ppm, or ranging from 2 ppm to 20 ppm, or ranging from 3 ppm to 15 ppm;

(p) α-bromo-toluic acid isomers in an amount ranging from 1 ppm to 100 ppm, or ranging from 2 ppm to 50 ppm, or ranging from 5 ppm to 25 ppm;

(q) bromo-benzoic acid in an amount ranging from 5 ppm to 50 ppm, or ranging from 10 ppm to 40 ppm, or ranging from 15 ppm to 35 ppm;

(r) bromo-acetic acid in an amount ranging from 1 ppm to 10 ppm;

(s) isomers of tolualdehyde in an amount ranging from 7 ppm to 50 ppm, or ranging from 8 ppm to 25 ppm, or ranging from 9 ppm to 20 ppm;

(t) isomers of phthaldehyde in an amount ranging from 0.25 ppm to 10 ppm, or ranging from 0.5 ppm to 5 ppm, or ranging from 0.75 ppm to 2 ppm; wherein the compound or compounds selected in (3) are different from the compound or compounds selected in (1) and (2);

and optionally, (4) at least one, or at least two, or at least three, or at least four, or at least five or at least six, or at least seven, or at least eight, or all of the following:

(a) Terephthalic acid in an amount of at least 1 ppm, or ranging from 1 ppm to 5000 ppm, or ranging from 5 ppm to 2500 ppm, or ranging from 10 ppm to 2000 ppm, or ranging from 15 ppm and 1000 ppm, or ranging from 20 ppm to 500 ppm;

(b) Isophthalic acid in an amount of at least 1 ppm, or ranging from 1 ppm to 5000 ppm, or ranging from 5 ppm to 2500 ppm, or ranging from 10 ppm to 2000 ppm, or ranging from 15 ppm and 1000 ppm, or ranging from 20 ppm to 500 ppm;

(c) phthalic acid in an amount of at least 1 ppm, or ranging from 1 ppm to 3000 ppm, or ranging from 2 ppm to 2000 ppm, or ranging from 3 ppm to 1000 ppm, or ranging from 4 ppm and 500 ppm;

(d) isomers of benzenetricarboxylic acid in an amount of at least 1 ppm, or ranging from 1 ppm to 3000 ppm, or ranging from 5 ppm to 2000 ppm, or ranging from 10 ppm to 1000 ppm, or ranging from 20 ppm and 500 ppm;

ES 2 688 198 T3 (e) benzoic acid in an amount of at least 1 ppm, or ranging from 1 ppm to 3000 ppm, or ranging from 5 ppm to 2000 ppm, or ranging from 10 ppm to 1000 ppm, or ranging from 20 ppm to 500 ppm;

(f) isomers of hydroxybenzoic acid in an amount of at least 1 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 5 ppm to 400 ppm, or ranging from 10 ppm to 200 ppm;

(g) isomers of hydroxymethylbenzoic acid in an amount of at least 1 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 5 ppm to 400 ppm, or ranging from 10 ppm to 200 ppm;

(h) isomers of dicarboxyphenyl acid in an amount of at least 1 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 5 ppm to 400 ppm, or ranging from 10 ppm to 200 ppm;

where the compound or compounds selected in (4) are different from the compound or compounds selected in (3).

II. In another embodiment of the invention, the dry carboxylic acid composition 280 comprises:

(1) carboxylic acid in an amount greater than 50 percent by weight, or greater than 60 percent by weight, or greater than 70 percent by weight, or greater than 80 percent by weight, or greater than 90 percent by weight, or greater than 95 percent by weight, or greater than 97 percent or greater than 98 percent or greater than 98.5 percent or greater than 99 percent or greater than 99.5 percent by weight;

^Y (2) (a) Carboxybenzaldehyde (CBA) isomers in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm; or (b) isomers of toluic acid (TA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm; or (c) both of the following:

(1) carboxybenzaldehyde (CBA) isomers in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

(2) isomers of toluic acid (TA) in an amount ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

where the total concentration of CBA and TA ranges between 1 and 2000 ppm, 1 ppm and 1000 ppm, or between 1 ppm and 500 ppm, or between 1 ppm and 250 ppm, or between 1 ppm and 125 ppm;

^Y (3) at least two, or at least three, or at least four, or at least five or at least six, or at least seven, or all of the following:

(a) Isophthalic acid in an amount of at least 50 ppm, or ranging from 50 ppm to 2000 ppm, or ranging from 75 ppm to 1500 ppm, or ranging from 100 ppm to 1000 ppm, or ranging from 150 ppm and 500 ppm, or ranging between 50 ppm, or 75 ppm, or 100 ppm, or 150 ppm and 500 ppm, or 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2 % by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight, or ranging between 500 ppm, or 1000 ppm and 2000 ppm, or 0.5% by weight or 1% by weight, or 2% by weight, or 3% by weight or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

(b) Benzene tricarboxylic acid isomers ranging from 140 ppm to 1000 ppm, or ranging from 175 ppm to 750 ppm, or ranging from 200 ppm to 500 ppm, or ranging from 150 ppm, or 175 ppm, or 200 ppm and 500 ppm, or 750 ppm, or 1000 ppm;

(c) isomers of dicarboxybiphenyl in an amount ranging from 20 ppm to 150 ppm, or ranging from 25 ppm to 100 ppm, or ranging from 25 ppm to 75 ppm, or ranging from 200 ppm, or 300 ppm, or 500 ppm and 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2% by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25 % by weight, or 49% by weight;

(d) phthalic acid in an amount of at least 20 ppm, or at least 50 ppm, or at least 100 ppm, or ranging from 20 ppm to 1000 ppm, or ranging from 50 ppm to 750 ppm, or

ES 2 688 198 T3 ranges from 100 ppm to 500 ppm, or ranges from 20 ppm, 50 ppm, 100 ppm and 500 ppm, or 750 ppm, or 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2% by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight, or ranging between 500 ppm, or 750 ppm, or 1000 ppm and 2000 ppm, or 0.5% by weight or 1% by weight, or 2% by weight, or 3% by weight or 5% by weight, or 10% by weight, or 25% by weight , or 49% by weight;

(e) isomers of hydroxybenzoic acid ranging from 3 ppm to 200 ppm, or ranging from 5 ppm to 175 ppm, or ranging from 20 ppm to 150 ppm, or ranging from 3 ppm, or 5 ppm or 20 ppm and 150 ppm, or 175 ppm, or 200 ppm, or 500 ppm, or 1000 ppm;

(f) isomers of hydroxymethylbenzoic acid in an amount of at least 40 ppm, or at least 80 ppm, or at least 100 ppm, or ranging from 40 ppm to 200 ppm, or ranging from 80 ppm to 180 ppm, or range from 100 ppm to 160 ppm, or ranging from 40 ppm, or 80 ppm, or 100 ppm to 500 ppm, or 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2% by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

(g) benzoic acid ranging from 60 ppm to 500 ppm, or ranging from 75 ppm to 400 ppm, or ranging from 100 ppm to 300 ppm, or ranging from 60 ppm, or 75 ppm, or 100 ppm to 300 ppm, or 500 ppm, or 1000 ppm;

(h) Terephthalic acid in an amount of at least 20 ppm, or at least 50 ppm, or at least 100 ppm, or ranging from 20 ppm to 1000 ppm, or ranging from 50 ppm to 750 ppm, or ranging from 100 ppm and 500 ppm, or ranging between 20 ppm, 50 ppm, 100 ppm and 500 ppm, or 750 ppm, or 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2 % by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight, or ranging between 500 ppm, or 750 ppm, or 1000 ppm and 2000 ppm, or 0.5% by weight or 1% by weight, or 2% by weight, or 3% by weight or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

III. In one embodiment of the invention, dry carboxylic acid composition 280 comprises:

(1) carboxylic acid in an amount greater than 50 percent by weight, or greater than 60 percent by weight, or greater than 70 percent by weight, or greater than 80 percent by weight, or greater than 90 percent by weight, or greater than 95 percent by weight, or greater than 97 percent or greater than 98 percent or greater than 98.5 percent or greater than 99 percent or greater than 99.5 percent by weight;

^Y (2) (a) Carboxybenzaldehyde (CBA) isomers in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm; or (b) isomers of toluic acid (TA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm; or (c) both of the following:

(1) carboxybenzaldehyde (CBA) isomers in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

(2) isomers of toluic acid (TA) in an amount ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

where the total concentration of CBA and TA ranges between 1 and 2000 ppm, 1 ppm and 1000 ppm, or between 1 ppm and 500 ppm, or between 1 ppm and 250 ppm, or between 1 ppm and 125 ppm;

^Y (3) at least two, or at least three, or at least four, or five, or all of the following:

(a) Isophthalic acid in an amount of at least 50 ppm, or ranging from 50 ppm to 2000 ppm, or ranging from 75 ppm to 1500 ppm, or ranging from 100 ppm to 1000 ppm, or ranging from 150 ppm and 500 ppm, or ranging between 50 ppm, or 75 ppm, or 100 ppm, or 150 ppm and 500 ppm, or 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2 % by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight, or ranging between 500 ppm, or 1000 ppm and 2000 ppm, or 0.5% by weight or 1% by weight, or 2% by weight, or 3% by weight or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

ES 2 688 198 T3 (b) isomers of benzene-tricarboxylic acid ranging from 140 ppm to 1000 ppm, or ranging from 175 ppm to 750 ppm, or ranging from 200 ppm to 500 ppm, or ranging from 150 ppm, or 175 ppm, or 200 ppm and 500 ppm, or 750 ppm, or 1000 ppm;

(c) isomers of dicarboxybiphenyl in an amount ranging from 20 ppm to 150 ppm, or ranging from 25 ppm to 100 ppm, or ranging from 25 ppm to 75 ppm, or ranging from 200 ppm, or 300 ppm, or 500 ppm and 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2% by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25 % by weight, or 49% by weight;

(d) phthalic acid in an amount of at least 20 ppm, or at least 50 ppm, or at least 100 ppm, or ranging from 20 ppm to 1000 ppm, or ranging from 50 ppm to 750 ppm, or ranging from 100 ppm and 500 ppm, or ranging between 20 ppm, 50 ppm, 100 ppm and 500 ppm, or 750 ppm, or 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2 % by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight, or ranging between 500 ppm, or 750 ppm, or 1000 ppm and 2000 ppm, or 0.5% by weight or 1% by weight, or 2% by weight, or 3% by weight or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

(e) benzoic acid ranging from 60 ppm to 500 ppm, or ranging from 75 ppm to 400 ppm, or ranging from 100 ppm to 300 ppm, or ranging from 60 ppm, or 75 ppm, or 100 ppm to 300 ppm, or 500 ppm, or 1000 ppm;

(f) Terephthalic acid in an amount of at least 20 ppm, or at least 50 ppm, or at least 100 ppm, or ranging from 20 ppm to 1000 ppm, or ranging from 50 ppm to 750 ppm, or ranging from 100 ppm and 500 ppm, or ranging between 20 ppm, 50 ppm, 100 ppm and 500 ppm, or 750 ppm, or 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2 % by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight, or ranging between 500 ppm, or 750 ppm, or 1000 ppm and 2000 ppm, or 0.5% by weight or 1% by weight, or 2% by weight, or 3% by weight or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

IV. In one embodiment of the invention, dry carboxylic acid composition 280 comprises:

(1) carboxylic acid in an amount greater than 50 percent by weight, or greater than 60 percent by weight, or greater than 70 percent by weight, or greater than 80 percent by weight, or greater than 90 percent by weight, or greater than 95 percent by weight, or greater than 97 percent or greater than 98 percent or greater than 98.5 percent or greater than 99 percent or greater than 99.5 percent by weight;

^Y (2) (a) Carboxybenzaldehyde (CBA) isomers in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm and 125 ppm; or (b) isomers of toluic acid (TA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm; or (c) both of the following:

(1) carboxybenzaldehyde (CBA) isomers in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

(2) isomers of toluic acid (TA) in an amount ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

where the total concentration of CBA and TA ranges between 1 and 2000 ppm, 1 ppm and 1000 ppm, or between 1 ppm and 500 ppm, or between 1 ppm and 250 ppm, or between 1 ppm and 125 ppm;

^Y (3) at least two, or at least three, or four, or all of the following:

(a) Isophthalic acid in an amount of at least 50 ppm, or ranging from 50 ppm to 2000 ppm, or ranging from 75 ppm to 1500 ppm, or ranging from 100 ppm to 1000 ppm, or ranging from 150 ppm and 500 ppm, or ranging between 50 ppm, or 75 ppm, or 100 ppm, or 150 ppm and 500 ppm, or 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2 % by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight, or that

ES 2 688 198 T3 ranges from 500 ppm, or 1000 ppm to 2000 ppm, or 0.5% by weight, or 1% by weight, or 2% by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

(b) Benzene tricarboxylic acid isomers ranging from 140 ppm to 1000 ppm, or ranging from 175 ppm to 750 ppm, or ranging from 200 ppm to 500 ppm, or ranging from 150 ppm, or 175 ppm, or 200 ppm and 500 ppm, or 750 ppm, or 1000 ppm;

(c) isomers of dicarboxybiphenyl in an amount ranging from 20 ppm to 150 ppm, or ranging from 25 ppm to 100 ppm, or ranging from 25 ppm to 75 ppm, or ranging from 200 ppm, or 300 ppm, or 500 ppm and 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2% by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25 % by weight, or 49% by weight;

(d) phthalic acid in an amount of at least 20 ppm, or at least 50 ppm, or at least 100 ppm, or ranging from 20 ppm to 1000 ppm, or ranging from 50 ppm to 750 ppm, or ranging from 100 ppm and 500 ppm, or ranging between 20 ppm, 50 ppm, 100 ppm and 500 ppm, or 750 ppm, or 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2 % by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight, or ranging between 500 ppm, or 750 ppm, or 1000 ppm and 2000 ppm, or 0.5% by weight or 1% by weight, or 2% by weight, or 3% by weight or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

(e) Terephthalic acid in an amount of at least 20 ppm, or at least 50 ppm, or at least 100 ppm, or ranging from 20 ppm to 1000 ppm, or ranging from 50 ppm to 750 ppm, or ranging from 100 ppm and 500 ppm, or ranging between 20 ppm, 50 ppm, 100 ppm and 500 ppm, or 750 ppm, or 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2 % by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight, or ranging between 500 ppm, or 750 ppm, or 1000 ppm and 2000 ppm, or 0.5% by weight or 1% by weight, or 2% by weight, or 3% by weight or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

V. In one embodiment of the invention, the dry carboxylic acid composition 280 comprises:

(1) carboxylic acid in an amount greater than 50 percent by weight, or greater than 60 percent by weight, or greater than 70 percent by weight, or greater than 80 percent by weight, or greater than 90 percent by weight, or greater than 95 percent by weight, or greater than 97 percent or greater than 98 percent or greater than 98.5 percent or greater than 99 percent or greater than 99.5 percent by weight;

^Y (2) (a) Carboxybenzaldehyde (CBA) isomers in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm and 125 ppm; or (b) isomers of toluic acid (TA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm; or (c) both of the following:

(1) carboxybenzaldehyde (CBA) isomers in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

(2) isomers of toluic acid (TA) in an amount ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

where the total concentration of CBA and TA ranges between 1 and 2000 ppm, 1 ppm and 1000 ppm, or between 1 ppm and 500 ppm, or between 1 ppm and 250 ppm, or between 1 ppm and 125 ppm;

^Y (3) at least two, or three, or all of the following:

(a) Isophthalic acid in an amount of at least 50 ppm, or ranging from 50 ppm to 2000 ppm, or ranging from 75 ppm to 1500 ppm, or ranging from 100 ppm to 1000 ppm, or ranging from 150 ppm and 500 ppm, or ranging between 50 ppm, or 75 ppm, or 100 ppm, or 150 ppm and 500 ppm, or 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2 % by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight, or ranging between 500 ppm, or 1000 ppm and 2000 ppm, or 0.5% by weight or 1% by weight, or 2% by weight, or 3% by weight or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

ES 2 688 198 T3 (b) isomers of benzene-tricarboxylic acid ranging from 140 ppm to 1000 ppm, or ranging from 175 ppm to 750 ppm, or ranging from 200 ppm to 500 ppm, or ranging from 150 ppm, or 175 ppm, or 200 ppm and 500 ppm, or 750 ppm, or 1000 ppm;

(c) isomers of dicarboxybiphenyl in an amount ranging from 20 ppm to 150 ppm, or ranging from 25 ppm to 100 ppm, or ranging from 25 ppm to 75 ppm, or ranging from 200 ppm, or 300 ppm, or 500 ppm and 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2% by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

(d) Terephthalic acid in an amount of at least 50 ppm, or ranging from 50 ppm to 2000 ppm, or ranging from 75 ppm to 1500 ppm, or ranging from 100 ppm to 1000 ppm, or ranging from 150 ppm and 500 ppm, or ranging between 50 ppm, or 75 ppm, or 100 ppm, or 150 ppm and 500 ppm, or 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2 % by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight, or ranging between 500 ppm, or 1000 ppm and 2000 ppm, or 0.5% by weight or 1% by weight, or 2% by weight, or 3% by weight or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

SAW. In one embodiment of the invention, dry carboxylic acid composition 280 comprises:

(1) carboxylic acid in an amount greater than 50 percent by weight, or greater than 60 percent by weight, or greater than 70 percent by weight, or greater than 80 percent by weight, or greater than 90 percent by weight, or greater than 95 percent by weight, or greater than 97 percent or greater than 98 percent or greater than 98.5 percent or greater than 99 percent or greater than 99.5 percent by weight;

^Y (2) (a) Carboxybenzaldehyde (CBA) isomers in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm and 125 ppm; or (b) isomers of toluic acid (TA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm; or (c) both of the following:

(1) carboxybenzaldehyde (CBA) isomers in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

(2) isomers of toluic acid (TA) in an amount ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

where the total concentration of CBA and TA ranges between 1 and 2000 ppm, 1 ppm and 1000 ppm, or between 1 ppm and 500 ppm, or between 1 ppm and 250 ppm, or between 1 ppm and 125 ppm;

^Y (3) at least two, or all of the following:

(a) Isophthalic acid in an amount of at least 50 ppm, or ranging from 50 ppm to 2000 ppm, or ranging from 75 ppm to 1500 ppm, or ranging from 100 ppm to 1000 ppm, or ranging from 150 ppm and 500 ppm, or ranging between 50 ppm, or 75 ppm, or 100 ppm, or 150 ppm and 500 ppm, or 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2 % by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight, or ranging between 500 ppm, or 1000 ppm and 2000 ppm, or 0.5% by weight or 1% by weight, or 2% by weight, or 3% by weight or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

(b) Benzene tricarboxylic acid isomers ranging from 140 ppm to 1000 ppm, or ranging from 175 ppm to 750 ppm, or ranging from 200 ppm to 500 ppm, or ranging from 150 ppm, or 175 ppm, or 200 ppm and 500 ppm, or 750 ppm, or 1000 ppm;

(c) isomers of dicarboxybiphenyl in an amount ranging from 20 ppm to 150 ppm, or ranging from 25 ppm to 100 ppm, or ranging from 25 ppm to 75 ppm, or ranging from 200 ppm, or 300 ppm, or 500 ppm and 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2% by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25 % by weight, or 49% by weight;

VII. In one embodiment of the invention, dry carboxylic acid composition 280 comprises:

ES 2 688 198 T3 (1) carboxylic acid in an amount greater than 50 percent by weight, or greater than 60 percent by weight, or greater than 70 percent by weight, or greater than 80 percent by weight, or greater than 90 percent by weight, or greater than 95 percent by weight, or greater than 97 percent or greater than 98 percent or greater than 98.5 percent or greater than 99 percent or greater than 99.5 percent in weigh;

^Y (2) (a) Carboxybenzaldehyde (CBA) isomers in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm; or (b) isomers of toluic acid (TA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm; or (c) both of the following:

(1) carboxybenzaldehyde (CBA) isomers in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

(2) isomers of toluic acid (TA) in an amount ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

where the total concentration of CBA and TA ranges between 1 and 2000 ppm, 1 ppm and 1000 ppm, or between 1 ppm and 500 ppm, or between 1 ppm and 250 ppm, or between 1 ppm and 125 ppm;

^Y (3) both of the following:

(a) Isophthalic acid in an amount of at least 50 ppm, or ranging from 50 ppm to 2000 ppm, or ranging from 75 ppm to 1500 ppm, or ranging from 100 ppm to 1000 ppm, or ranging from 150 ppm and 500 ppm, or ranging between 50 ppm, or 75 ppm, or 100 ppm, or 150 ppm and 500 ppm, or 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2 % by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight, or ranging between 500 ppm, or 1000 ppm and 2000 ppm, or 0.5% by weight or 1% by weight, or 2% by weight, or 3% by weight or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

(b) Benzene tricarboxylic acid isomers ranging from 140 ppm to 1000 ppm, or ranging from 175 ppm to 750 ppm, or ranging from 200 ppm to 500 ppm, or ranging from 150 ppm, or 175 ppm, or 200 ppm and 500 ppm, or 750 ppm, or 1000 ppm;

VIII. In one embodiment of the invention, dry carboxylic acid composition 280 comprises:

(1) carboxylic acid in an amount greater than 50 percent by weight, or greater than 60 percent by weight, or greater than 70 percent by weight, or greater than 80 percent by weight, or greater than 90 percent by weight, or greater than 95 percent by weight, or greater than 97 percent or greater than 98 percent or greater than 98.5 percent or greater than 99 percent or greater than 99.5 percent by weight;

^Y (2) (a) Carboxybenzaldehyde (CBA) isomers in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm and 125 ppm; or (b) isomers of toluic acid (TA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm; or (c) both of the following:

(1) carboxybenzaldehyde (CBA) isomers in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

(2) isomers of toluic acid (TA) in an amount ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

where the total concentration of CBA and TA ranges between 1 and 2000 ppm, 1 ppm and 1000 ppm, or between 1 ppm and 500 ppm, or between 1 ppm and 250 ppm, or between 1 ppm and 125 ppm;

^Y

ES 2 688 198 T3 (3) both of the following:

(a) Isophthalic acid in an amount of at least 50 ppm, or ranging from 50 ppm to 2000 ppm, or ranging from 75 ppm to 1500 ppm, or ranging from 100 ppm to 1000 ppm, or ranging from 150 ppm and 500 ppm, or ranging between 50 ppm, or 75 ppm, or 100 ppm, or 150 ppm and 500 ppm, or 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2 % by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight, or ranging between 500 ppm, or 1000 ppm and 2000 ppm, or 0.5% by weight or 1% by weight, or 2% by weight, or 3% by weight or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

(b) isomers of dicarboxybiphenyl in an amount ranging from 20 ppm to 150 ppm, or ranging from 25 ppm to 100 ppm, or ranging from 25 ppm to 75 ppm, or ranging from 200 ppm, or 300 ppm, or 500 ppm and 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2% by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25 % by weight, or 49% by weight;

IX. In one embodiment of the invention, dry carboxylic acid composition 280 comprises:

(1) carboxylic acid in an amount greater than 50 percent by weight, or greater than 60 percent by weight, or greater than 70 percent by weight, or greater than 80 percent by weight, or greater than 90 percent by weight, or greater than 95 percent by weight, or greater than 97 percent or greater than 98 percent or greater than 98.5 percent or greater than 99 percent or greater than 99.5 percent by weight;

^Y (2) (a) Carboxybenzaldehyde (CBA) isomers in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm and 125 ppm; or (b) isomers of toluic acid (TA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm; or (c) both of the following:

(1) carboxybenzaldehyde (CBA) isomers in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

(2) isomers of toluic acid (TA) in an amount ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

where the total concentration of CBA and TA ranges between 1 and 2000 ppm, 1 ppm and 1000 ppm, or between 1 ppm and 500 ppm, or between 1 ppm and 250 ppm, or between 1 ppm and 125 ppm;

^Y (3) both of the following:

(a) Benzene-tricarboxylic acid isomers ranging from 140 ppm to 1000 ppm, or ranging from 175 ppm to 750 ppm, or ranging from 200 ppm to 500 ppm, or ranging from 150 ppm, or 175 ppm, or 200 ppm and 500 ppm, or 750 ppm, or 1000 ppm;

(b) isomers of dicarboxybiphenyl in an amount ranging from 20 ppm to 150 ppm, or ranging from 25 ppm to 100 ppm, or ranging from 25 ppm to 75 ppm, or ranging from 200 ppm, or 300 ppm, or 500 ppm and 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2% by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25 % by weight, or 49% by weight;

X. In one embodiment of the invention, dry carboxylic acid composition 280 comprises:

(1) carboxylic acid in an amount greater than 50 percent by weight, or greater than 60 percent by weight, or greater than 70 percent by weight, or greater than 80 percent by weight, or greater than 90 percent by weight, or greater than 95 percent by weight, or greater than 97 percent or greater than 98 percent or greater than 98.5 percent or greater than 99 percent or greater than 99.5 percent by weight;

^Y (2)

ES 2 688 198 T3 (a) isomers of carboxybenzaldehyde (CBA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm and 125 ppm; or (b) isomers of toluic acid (TA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm; or (c) both of the following:

(1) carboxybenzaldehyde (CBA) isomers in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

(2) isomers of toluic acid (TA) in an amount ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

where the total concentration of CBA and TA ranges between 1 and 2000 ppm, 1 ppm and 1000 ppm, or between 1 ppm and 500 ppm, or between 1 ppm and 250 ppm, or between 1 ppm and 125 ppm;

^Y (3) at least two, or all of the following:

(a) Terephthalic acid in an amount of at least 50 ppm, or ranging from 50 ppm to 2000 ppm, or ranging from 75 ppm to 1500 ppm, or ranging from 100 ppm to 1000 ppm, or ranging from 150 ppm and 500 ppm, or ranging between 50 ppm, or 75 ppm, or 100 ppm, or 150 ppm and 500 ppm, or 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2 % by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight, or ranging between 500 ppm, or 1000 ppm and 2000 ppm, or 0.5% by weight or 1% by weight, or 2% by weight, or 3% by weight or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

(b) Benzene tricarboxylic acid isomers ranging from 140 ppm to 1000 ppm, or ranging from 175 ppm to 750 ppm, or ranging from 200 ppm to 500 ppm, or ranging from 150 ppm, or 175 ppm, or 200 ppm and 500 ppm, or 750 ppm, or 1000 ppm;

(c) isomers of dicarboxybiphenyl in an amount ranging from 20 ppm to 150 ppm, or ranging from 25 ppm to 100 ppm, or ranging from 25 ppm to 75 ppm, or ranging from 200 ppm, or 300 ppm, or 500 ppm and 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2% by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25 % by weight, or 49% by weight;

XI. In one embodiment of the invention, dry carboxylic acid composition 280 comprises:

(1) carboxylic acid in an amount greater than 50 percent by weight, or greater than 60 percent by weight, or greater than 70 percent by weight, or greater than 80 percent by weight, or greater than 90 percent by weight, or greater than 95 percent by weight, or greater than 97 percent or greater than 98 percent or greater than 98.5 percent or greater than 99 percent or greater than 99.5 percent by weight;

^Y (2) (a) Carboxybenzaldehyde (CBA) isomers in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm and 125 ppm; or (b) isomers of toluic acid (TA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm; or (c) both of the following:

(1) carboxybenzaldehyde (CBA) isomers in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

(2) isomers of toluic acid (TA) in an amount ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

where the total concentration of CBA and TA ranges between 1 and 2000 ppm, 1 ppm and 1000 ppm, or between 1 ppm and 500 ppm, or between 1 ppm and 250 ppm, or between 1 ppm and 125 ppm; ^Y (3) both of the following:

ES 2 688 198 T3 (a) Terephthalic acid in an amount of at least 50 ppm, or ranging from 50 ppm to 2000 ppm, or ranging from 75 ppm to 1500 ppm, or ranging from 100 ppm to 1000 ppm, or ranging from 150 ppm to 500 ppm, or ranging from 50 ppm, or 75 ppm, or 100 ppm, or 150 ppm to 500 ppm, or 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2% by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight, or ranging between 500 ppm, or 1000 ppm and 2000 ppm, or 0.5% by weight or 1% by weight, or 2% by weight, or 3% by weight or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

(b) Benzene tricarboxylic acid isomers ranging from 140 ppm to 1000 ppm, or ranging from 175 ppm to 750 ppm, or ranging from 200 ppm to 500 ppm, or ranging from 150 ppm, or 175 ppm, or 200 ppm and 500 ppm, or 750 ppm, or 1000 ppm;

XII. In one embodiment of the invention, dry carboxylic acid composition 280 comprises:

(1) carboxylic acid in an amount greater than 50 percent by weight, or greater than 60 percent by weight, or greater than 70 percent by weight, or greater than 80 percent by weight, or greater than 90 percent by weight, or greater than 95 percent by weight, or greater than 97 percent or greater than 98 percent or greater than 98.5 percent or greater than 99 percent or greater than 99.5 percent by weight;

^Y (2) (a) Carboxybenzaldehyde (CBA) isomers in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm and 125 ppm; or (b) isomers of toluic acid (TA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm; or (c) both of the following:

(1) carboxybenzaldehyde (CBA) isomers in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

(2) isomers of toluic acid (TA) in an amount ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

where the total concentration of CBA and TA ranges between 1 and 2000 ppm, 1 ppm and 1000 ppm, or between 1 ppm and 500 ppm, or between 1 ppm and 250 ppm, or between 1 ppm and 125 ppm;

^Y (3) both of the following:

(a) Terephthalic acid in an amount of at least 50 ppm, or ranging from 50 ppm to 2000 ppm, or ranging from 75 ppm to 1500 ppm, or ranging from 100 ppm to 1000 ppm, or ranging from 150 ppm and 500 ppm, or ranging between 50 ppm, or 75 ppm, or 100 ppm, or 150 ppm and 500 ppm, or 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2 % by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight, or ranging between 500 ppm, or 1000 ppm and 2000 ppm, or 0.5% by weight or 1% by weight, or 2% by weight, or 3% by weight or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

(b) isomers of dicarboxybiphenyl in an amount ranging from 20 ppm to 150 ppm, or ranging from 25 ppm to 100 ppm, or ranging from 25 ppm to 75 ppm, or ranging from 200 ppm, or 300 ppm, or 500 ppm and 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2% by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25 % by weight, or 49% by weight;

XIII. In another embodiment of the invention, the dry carboxylic acid composition 280 comprises:

(1) carboxylic acid in an amount greater than 50 percent by weight, or greater than 60 percent by weight, or greater than 70 percent by weight, or greater than 80 percent by weight, or greater than 90 percent by weight, or greater than 95 percent by weight, or greater than 97 percent or greater than 98 percent or greater than 98.5 percent or greater than 99 percent or greater than 99.5 percent by weight; and (2) carboxybenzaldehyde (CBA) isomers in an amount ranging from 1 ppm to 500 ppm, and (3) all of the following:

ES 2 688 198 T3 (a) phthalic acid in an amount of at least 50 ppm, or ranging from 50 ppm to 2000 ppm, or ranging from 75 ppm to 1500 ppm, or ranging from 100 ppm to 1000 ppm, or ranging from 150 ppm to 500 ppm, or ranging from 50 ppm, or 75 ppm, or 100 ppm, or 150 ppm to 500 ppm, or 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2% by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight, or ranging between 500 ppm, or 1000 ppm and 2000 ppm, or 0.5% by weight or 1% by weight, or 2% by weight, or 3% by weight or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

(b) Benzene tricarboxylic acid isomers ranging from 140 ppm to 1000 ppm, or ranging from 175 ppm to 750 ppm, or ranging from 200 ppm to 500 ppm, or ranging from 150 ppm, or 175 ppm, or 200 ppm and 500 ppm, or 750 ppm, or 1000 ppm;

(c) isomers of dicarboxybiphenyl in an amount ranging from 20 ppm to 150 ppm, or ranging from 25 ppm to 100 ppm, or ranging from 25 ppm to 75 ppm, or ranging from 200 ppm, or 300 ppm, or 500 ppm and 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2% by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25 % by weight, or 49% by weight;

Isophthalic acid compositions

I. In one embodiment of the invention, dry carboxylic acid composition 280 comprises:

(1) Isophthalic acid in an amount greater than 50 percent by weight, or greater than 60 percent by weight, or greater than 70 percent by weight, or greater than 80 percent by weight, or greater than 90 percent by weight, or greater than 95 percent by weight, or greater than 97 percent or greater than 98 percent or greater than 98.5 percent or greater than 99 percent, or greater than 99.5 percent by weight;

and (2) (a) 3-carboxybenzaldehyde (3-CBA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging between 1 ppm and 125 ppm; or (b) m-toluic acid (isomers of m-TA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging between 1 ppm and 125 ppm; or (c) both of the following:

(1) 3-carboxybenzaldehyde (3-CBA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

(2) isomers of m-toluic acid (m-TA) in an amount ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

where the total concentration of 3-CBA and m-TA ranges between 1 ppm and 2000 ppm, 1 ppm and 1000 ppm, or between 1 ppm and 500 ppm, or between 1 ppm and 250 ppm, or between 1 ppm and 125 ppm; and (3) at least one, or at least two, or at least three, or at least four, or at least five, or at least six, or at least seven, or at least eight, or at least nine, or at least least ten, or at least eleven, or at least twelve, or at least thirteen, or at least fourteen, or at least fifteen, or at least sixteen, or at least seventeen, or at least eighteen, or at least nineteen, or all the following:

(a) Terephthalic acid in an amount of at least 50 ppm, or ranging from 50 ppm to 2000 ppm, or ranging from 75 ppm to 1500 ppm, or ranging from 100 ppm to 1000 ppm, or ranging from 150 ppm and 500 ppm;

(b) Phthalic acid in an amount of at least 20 ppm, or at least 50 ppm, or at least 100 ppm, or ranging from 20 ppm to 1000 ppm, or ranging from 50 ppm to 750 ppm, or ranging from 100 ppm and 500 ppm;

(c) isomers of benzenetricarboxylic acid in an amount of at least 140 ppm, or ranging from 140 ppm to 1000 ppm, or ranging from 175 ppm to 750 ppm, or ranging from 200 ppm to 500 ppm;

(d) benzoic acid in an amount of at least 50 ppm, or at least 75 ppm, or at least 100 ppm; or ranging from 50 ppm to 500 ppm, or ranging from 75 ppm to 400 ppm, or ranging from 100 ppm to 300 ppm;

ES 2 688 198 T3 (e) 3-hydroxybenzoic acid in an amount of at least 3 ppm, at least 5 ppm, or at least 20 ppm, or ranging from 3 ppm to 200 ppm, or ranging from 5 ppm to 175 ppm, or ranging from 20 ppm to 150 ppm;

(f) 3-Hydroxymethylbenzoic acid in an amount of at least 40 ppm, or at least 80 ppm, or at least 100 ppm, or ranging from 40 ppm to 200 ppm, or ranging from 80 ppm to 180 ppm, or ranges from 100 ppm to 160 ppm;

(g) 3,3'-dicarboxybiphenyl isomers in an amount ranging from 20 ppm to 150 ppm, or ranging from 25 ppm to 100 ppm, or ranging from 25 ppm to 75 ppm;

(h) isomers of dicarboxyanthraquinone in an amount less than 1 ppm, or less than 0.5 ppm, or less than 0.4 ppm, or less than 0.35 ppm;

(i) isomers of dicarboxystilbene in an amount ranging from more than 7 ppm; or more than 10 ppm;

(j) isomers of tricarboxybiphenyl in an amount ranging from 8 ppm to 100 ppm, or ranging from 9 ppm to 50 ppm, or ranging from 10 ppm to 25 ppm;

(k) isomers of tricarboxybenzophenone in an amount ranging from 5 ppm to 100 ppm, or ranging from 6 ppm to 75 ppm, or ranging from 7 ppm to 60 ppm;

(l) isomers of dicarboxybenzophenone in an amount ranging from 10 ppm to 150 ppm, or ranging from 12 ppm to 100 ppm, or ranging from 15 ppm to 75 ppm;

(m) isomers of dicarboxybenzyl in an amount ranging from 1 ppm to 30 ppm, or ranging from 2 ppm to 20 ppm, or ranging from 3 ppm to 10 ppm;

(n) isomers of form-acet-hydroxybenzoic acid in an amount ranging from 1 ppm to 20 ppm, or ranging from 2 ppm to 15 ppm, or ranging from 3 ppm to 10 ppm;

(o) isomers of acet-hydroxymethylbenzoic acid in an amount ranging from 1 ppm to 30 ppm, or ranging from 2 ppm to 20 ppm, or ranging from 3 ppm to 15 ppm;

(p) α-bromo-toluic acid in an amount ranging from 1 ppm to 100 ppm, or ranging from 2 ppm to 50 ppm, or ranging from 5 ppm to 25 ppm;

(q) bromo-benzoic acid in an amount ranging from 5 ppm to 50 ppm, or ranging from 10 ppm to 40 ppm, or ranging from 15 ppm to 35 ppm;

(r) bromo-acetic acid in an amount ranging from 1 ppm to 10 ppm;

(s) m-tolualdehyde in an amount ranging from 7 ppm to 50 ppm, or ranging from 8 ppm to 25 ppm, or ranging from 9 ppm to 20 ppm;

(t) isophthaldehyde in an amount ranging from 0.25 ppm to 10 ppm, or ranging from 0.5 ppm to 5 ppm, or ranging from 0.75 ppm to 2 ppm; and optionally (4) at least one, or at least two, or at least three, or at least four, or at least five or at least six, or at least seven, or all of the following:

(a) Terephthalic acid in an amount of at least 1 ppm, or ranging from 1 ppm to 5000 ppm, or ranging from 5 ppm to 2500 ppm, or ranging from 10 ppm to 2000 ppm, or ranging from 15 ppm and 1000 ppm, or ranging from 20 ppm to 500 ppm;

(b) phthalic acid in an amount of at least 1 ppm, or ranging from 1 ppm to 3000 ppm, or ranging from 2 ppm to 2000 ppm, or ranging from 3 ppm to 1000 ppm, or ranging from 4 ppm and 500 ppm;

(c) Benzenetricarboxylic acid isomers in an amount of at least 1 ppm, or ranging from 1 ppm to 3000 ppm, or ranging from 5 ppm to 2000 ppm, or ranging from 10 ppm to 1000 ppm, or ranging from 20 ppm and 500 ppm;

(d) benzoic acid in an amount of at least 1 ppm, or ranging from 1 ppm to 3000 ppm, or ranging from 5 ppm to 2000 ppm, or ranging from 10 ppm to 1000 ppm, or ranging from 20 ppm and 500 ppm;

(e) 3-hydroxybenzoic acid in an amount of at least 1 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 5 ppm to 400 ppm, or ranging from 10 ppm to 200 ppm;

(f) 3-hydroxybenzoic acid in an amount of at least 1 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 5 ppm to 400 ppm, or ranging from 10 ppm to 200 ppm;

(g) 3,3'-dicarboxybiphenyl in an amount of at least 1 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 5 ppm to 400 ppm, or ranging from 10 ppm to 200 ppm;

(h) isomers of dicarboxyanthraquinone in an amount of at least 0.1 ppm, or ranging from 0.1 ppm to 5 ppm, or ranging from 0.2 ppm to 4 ppm, or ranging from 0.3 ppm to 3 ppm;

ES 2 688 198 T3 where the compound or compounds selected in (4) are different from the compound or compounds selected in (3).

II. In one embodiment of the invention, dry carboxylic acid composition 280 comprises:

(1) Isophthalic acid in an amount greater than 50 percent by weight, or greater than 60 percent by weight, or greater than 70 percent by weight, or greater than 80 percent by weight, or greater than 90 percent by weight, or greater than 95 percent by weight, or greater than 97 percent or greater than 98 percent or greater than 98.5 percent or greater than 99 percent, or greater than 99.5 percent by weight;

and (2) (a) 3-carboxybenzaldehyde (3-CBA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging between 1 ppm and 125 ppm; or (b) m-toluic acid (m-TA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm and 125 ppm; or (c) both of the following:

(1) 3-carboxybenzaldehyde (3-CBA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

(2) m-toluic acid (m-TA) in an amount ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

where the total concentration of 3-CBA and m-TA ranges between 1 ppm and 2000 ppm, 1 ppm and 1000 ppm, or between 1 ppm and 500 ppm, or between 1 ppm and 250 ppm, or between 1 ppm and 125 ppm;

^Y (3) at least two, or at least three, or at least four, or at least five or at least six, or all of the following:

(a) Terephthalic acid in an amount of at least 50 ppm, or ranging from 50 ppm to 2000 ppm, or ranging from 75 ppm to 1500 ppm, or ranging from 100 ppm to 1000 ppm, or ranging from 150 ppm and 500 ppm, or ranging between 50 ppm, or 75 ppm, or 100 ppm, or 150 ppm and 500 ppm, or 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2 % by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight, or ranging between 500 ppm, or 1000 ppm and 2000 ppm, or 0.5% by weight or 1% by weight, or 2% by weight, or 3% by weight or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

(b) Benzene tricarboxylic acid isomers ranging from 140 ppm to 1000 ppm, or ranging from 175 ppm to 750 ppm, or ranging from 200 ppm to 500 ppm, or ranging from 150 ppm, or 175 ppm, or 200 ppm and 500 ppm, or 750 ppm, or 1000 ppm;

(c) 3,3'-dicarboxybiphenyl in an amount ranging from 20 ppm to 150 ppm, or ranging from 25 ppm to 100 ppm, or ranging from 25 ppm to 75 ppm, or ranging from 200 ppm, or 300 ppm, or 500 ppm and 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2% by weight, or 3% by weight, or 5% by weight, or 10% by weight , or 25% by weight, or 49% by weight;

(d) phthalic acid in an amount of at least 20 ppm, or at least 50 ppm, or at least 100 ppm, or ranging from 20 ppm to 1000 ppm, or ranging from 50 ppm to 750 ppm, or ranging from 100 ppm and 500 ppm, or ranging between 20 ppm, 50 ppm, 100 ppm and 500 ppm, or 750 ppm, or 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2 % by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight, or ranging between 500 ppm, or 750 ppm, or 1000 ppm and 2000 ppm, or 0.5% by weight or 1% by weight, or 2% by weight, or 3% by weight or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

(e) 3-hydroxybenzoic acid ranging from 3 ppm to 200 ppm, or ranging from 5 ppm to 175 ppm, or ranging from 20 ppm to 150 ppm, or ranging from 3 ppm, or 5 ppm, or 20 ppm and 150 ppm, or 175 ppm, or 200 ppm, or 500 ppm, or 1000 ppm;

(f) 3-hydroxymethylbenzoic acid in an amount of at least 40 ppm, or at least 80 ppm, or at least 100 ppm, or ranging from 40 ppm to 200 ppm, or ranging from 80 ppm to 180 ppm, or ranges from 100 ppm to 160 ppm, or ranges from 40 ppm, or 80 ppm, or 100 ppm to 500 ppm, or 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2% by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

ES 2 688 198 T3 (g) benzoic acid ranging from 60 ppm to 500 ppm, or ranging from 75 ppm to 400 ppm, or ranging from 100 ppm to 300 ppm, or ranging from 60 ppm, or 75 ppm, or 100 ppm and 300 ppm, or 500 ppm, or 1000 ppm;

III. In one embodiment of the invention, dry carboxylic acid composition 280 comprises:

(1) Isophthalic acid in an amount greater than 50 percent by weight, or greater than 60 percent by weight, or greater than 70 percent by weight, or greater than 80 percent by weight, or greater than 90 percent by weight, or greater than 95 percent by weight, or greater than 97 percent or greater than 98 percent or greater than 98.5 percent or greater than 99 percent, or greater than 99.5 percent by weight;

and (2) (a) 3-carboxybenzaldehyde (3-CBA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging between 1 ppm and 125 ppm; or (b) m-toluic acid (m-TA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm and 125 ppm; or (c) both of the following:

(1) 3-carboxybenzaldehyde (3-CBA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

(2) m-toluic acid (m-TA) in an amount ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

where the total concentration of 3-CBA and m-TA ranges between 1 ppm and 2000 ppm, 1 ppm and 1000 ppm, or between 1 ppm and 500 ppm, or between 1 ppm and 250 ppm, or between 1 ppm and 125 ppm;

^Y (3) at least two, or at least three, or at least four, or all of the following:

(a) Terephthalic acid in an amount of at least 50 ppm, or ranging from 50 ppm to 2000 ppm, or ranging from 75 ppm to 1500 ppm, or ranging from 100 ppm to 1000 ppm, or ranging from 150 ppm and 500 ppm, or ranging between 50 ppm, or 75 ppm, or 100 ppm, or 150 ppm and 500 ppm, or 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2 % by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight, or ranging between 500 ppm, or 1000 ppm and 2000 ppm, or 0.5% by weight or 1% by weight, or 2% by weight, or 3% by weight or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

(b) Benzene tricarboxylic acid isomers ranging from 140 ppm to 1000 ppm, or ranging from 175 ppm to 750 ppm, or ranging from 200 ppm to 500 ppm, or ranging from 150 ppm, or 175 ppm, or 200 ppm and 500 ppm, or 750 ppm, or 1000 ppm;

(c) 3,3'-dicarboxybiphenyl in an amount ranging from 20 ppm to 150 ppm, or ranging from 25 ppm to 100 ppm, or ranging from 25 ppm to 75 ppm, or ranging from 200 ppm, or 300 ppm, or 500 ppm and 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2% by weight, or 3% by weight, or 5% by weight, or 10% by weight , or 25% by weight, or 49% by weight;

(d) phthalic acid in an amount of at least 20 ppm, or at least 50 ppm, or at least 100 ppm, or ranging from 20 ppm to 1000 ppm, or ranging from 50 ppm to 750 ppm, or ranging from 100 ppm and 500 ppm, or ranging between 20 ppm, 50 ppm, 100 ppm and 500 ppm, or 750 ppm, or 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2 % by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight, or ranging between 500 ppm, or 750 ppm, or 1000 ppm and 2000 ppm, or 0.5% by weight or 1% by weight, or 2% by weight, or 3% by weight or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

(e) benzoic acid ranging from 60 ppm to 500 ppm, or ranging from 75 ppm to 400 ppm, or ranging from 100 ppm to 300 ppm, or ranging from 60 ppm, or 75 ppm, or 100 ppm to 300 ppm, or 500 ppm, or 1000 ppm;

IV. In one embodiment of the invention, dry carboxylic acid composition 280 comprises:

(1) Isophthalic acid in an amount greater than 50 percent by weight, or greater than 60 percent by weight, or greater than 70 percent by weight, or greater than 80 percent by weight, or greater than 90 percent

ES 2 688 198 T3 percent by weight, or greater than 95 percent by weight, or greater than 97 percent, or greater than 98 percent, or greater than 98.5 percent, or greater than 99 percent, or greater than 99, 5 percent by weight;

and (2) (a) 3-carboxybenzaldehyde (3-CBA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging between 1 ppm and 125 ppm; or (b) m-toluic acid (m-TA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm and 125 ppm; or (c) both of the following:

(1) 3-carboxybenzaldehyde (3-CBA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

(2) m-toluic acid (m-TA) in an amount ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

where the total concentration of 3-CBA and m-TA ranges between 1 ppm and 2000 ppm, 1 ppm and 1000 ppm, or between 1 ppm and 500 ppm, or between 1 ppm and 250 ppm, or between 1 ppm and 125 ppm;

^Y (3) at least two, or at least three, or all of the following:

(a) Terephthalic acid in an amount of at least 50 ppm, or ranging from 50 ppm to 2000 ppm, or ranging from 75 ppm to 1500 ppm, or ranging from 100 ppm to 1000 ppm, or ranging from 150 ppm and 500 ppm, or ranging between 50 ppm, or 75 ppm, or 100 ppm, or 150 ppm and 500 ppm, or 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2 % by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight, or ranging between 500 ppm, or 1000 ppm and 2000 ppm, or 0.5% by weight or 1% by weight, or 2% by weight, or 3% by weight or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

(b) Benzene tricarboxylic acid isomers ranging from 140 ppm to 1000 ppm, or ranging from 175 ppm to 750 ppm, or ranging from 200 ppm to 500 ppm, or ranging from 150 ppm, or 175 ppm, or 200 ppm and 500 ppm, or 750 ppm, or 1000 ppm;

(c) 3,3'-dicarboxybiphenyl in an amount ranging from 20 ppm to 150 ppm, or ranging from 25 ppm to 100 ppm, or ranging from 25 ppm to 75 ppm, or ranging from 200 ppm, or 300 ppm, or 500 ppm and 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2% by weight, or 3% by weight, or 5% by weight, or 10% by weight , or 25% by weight, or 49% by weight;

(d) phthalic acid in an amount of at least 20 ppm, or at least 50 ppm, or at least 100 ppm, or ranging from 20 ppm to 1000 ppm, or ranging from 50 ppm to 750 ppm, or ranging from 100 ppm and 500 ppm, or ranging between 20 ppm, 50 ppm, 100 ppm and 500 ppm, or 750 ppm, or 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2 % by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight, or ranging between 500 ppm, or 750 ppm, or 1000 ppm and 2000 ppm, or 0.5% by weight or 1% by weight, or 2% by weight, or 3% by weight or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

V. In one embodiment of the invention, the dry carboxylic acid composition 280 comprises:

(1) Isophthalic acid in an amount greater than 50 percent by weight, or greater than 60 percent by weight, or greater than 70 percent by weight, or greater than 80 percent by weight, or greater than 90 percent by weight, or greater than 95 percent by weight, or greater than 97 percent or greater than 98 percent or greater than 98.5 percent or greater than 99 percent, or greater than 99.5 percent by weight;

and (2) (a) 3-carboxybenzaldehyde (3-CBA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging between 1 ppm and 125 ppm; or (b) m-toluic acid (m-TA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm and 125 ppm; or (c) both of the following:

ES 2 688 198 T3 (1) 3-carboxybenzaldehyde (3-CBA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging between 1 ppm and 125 ppm;

(2) m-toluic acid (m-TA) in an amount ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

where the total concentration of 3-CBA and m-TA ranges between 1 ppm and 2000 ppm, 1 ppm and 1000 ppm, or between 1 ppm and 500 ppm, or between 1 ppm and 250 ppm, or between 1 ppm and 125 ppm;

^Y (3) at least two or all of the following:

(a) Terephthalic acid in an amount of at least 50 ppm, or ranging from 50 ppm to 2000 ppm, or ranging from 75 ppm to 1500 ppm, or ranging from 100 ppm to 1000 ppm, or ranging from 150 ppm and 500 ppm, or ranging between 50 ppm, or 75 ppm, or 100 ppm, or 150 ppm and 500 ppm, or 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2 % by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight, or ranging between 500 ppm, or 1000 ppm and 2000 ppm, or 0.5% by weight or 1% by weight, or 2% by weight, or 3% by weight or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

(b) Benzene tricarboxylic acid isomers ranging from 140 ppm to 1000 ppm, or ranging from 175 ppm to 750 ppm, or ranging from 200 ppm to 500 ppm, or ranging from 150 ppm, or 175 ppm, or 200 ppm and 500 ppm, or 750 ppm, or 1000 ppm;

(c) 3,3'-dicarboxybiphenyl in an amount ranging from 20 ppm to 150 ppm, or ranging from 25 ppm to 100 ppm, or ranging from 25 ppm to 75 ppm, or ranging from 200 ppm, or 300 ppm, or 500 ppm and 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2% by weight, or 3% by weight, or 5% by weight, or 10% by weight , or 25% by weight, or 49% by weight;

SAW. In one embodiment of the invention, dry carboxylic acid composition 280 comprises:

(1) Isophthalic acid in an amount greater than 50 percent by weight, or greater than 60 percent by weight, or greater than 70 percent by weight, or greater than 80 percent by weight, or greater than 90 percent by weight, or greater than 95 percent by weight, or greater than 97 percent or greater than 98 percent or greater than 98.5 percent or greater than 99 percent, or greater than 99.5 percent by weight;

and (2) (a) 3-carboxybenzaldehyde (3-CBA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging between 1 ppm and 125 ppm; or (b) m-toluic acid (m-TA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm and 125 ppm; or (c) both of the following:

(1) 3-carboxybenzaldehyde (3-CBA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

(2) m-toluic acid (m-TA) in an amount ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

where the total concentration of 3-CBA and m-TA ranges between 1 ppm and 2000 ppm, 1 ppm and 1000 ppm, or between 1 ppm and 500 ppm, or between 1 ppm and 250 ppm, or between 1 ppm and 125 ppm;

^Y (3) both of the following:

(a) Terephthalic acid in an amount of at least 50 ppm, or ranging from 50 ppm to 2000 ppm, or ranging from 75 ppm to 1500 ppm, or ranging from 100 ppm to 1000 ppm, or ranging from 150 ppm and 500 ppm, or ranging between 50 ppm, or 75 ppm, or 100 ppm, or 150 ppm and 500 ppm, or 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2 % by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight, or ranging between 500 ppm, or 1000 ppm and 2000 ppm, or 0.5% by weight or 1% by weight, or 2% by weight, or 3% by weight or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

ES 2 688 198 T3 (b) isomers of benzene-tricarboxylic acid ranging from 140 ppm to 1000 ppm, or ranging from 175 ppm to 750 ppm, or ranging from 200 ppm to 500 ppm, or ranging from 150 ppm, or 175 ppm, or 200 ppm and 500 ppm, or 750 ppm, or 1000 ppm;

VII. In one embodiment of the invention, dry carboxylic acid composition 280 comprises:

(1) Isophthalic acid in an amount greater than 50 percent by weight, or greater than 60 percent by weight, or greater than 70 percent by weight, or greater than 80 percent by weight, or greater than 90 percent by weight, or greater than 95 percent by weight, or greater than 97 percent or greater than 98 percent or greater than 98.5 percent or greater than 99 percent, or greater than 99.5 percent by weight;

and (2) (a) 3-carboxybenzaldehyde (3-CBA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging between 1 ppm and 125 ppm; or (b) m-toluic acid (m-TA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm and 125 ppm; or (c) both of the following:

(1) 3-carboxybenzaldehyde (3-CBA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

(2) m-toluic acid (m-TA) in an amount ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

where the total concentration of 3-CBA and m-TA ranges between 1 ppm and 2000 ppm, 1 ppm and 1000 ppm, or between 1 ppm and 500 ppm, or between 1 ppm and 250 ppm, or between 1 ppm and 125 ppm;

^Y (3) both of the following:

(a) Terephthalic acid in an amount of at least 50 ppm, or ranging from 50 ppm to 2000 ppm, or ranging from 75 ppm to 1500 ppm, or ranging from 100 ppm to 1000 ppm, or ranging from 150 ppm and 500 ppm, or ranging between 50 ppm, or 75 ppm, or 100 ppm, or 150 ppm and 500 ppm, or 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2 % by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight, or ranging between 500 ppm, or 1000 ppm and 2000 ppm, or 0.5% by weight or 1% by weight, or 2% by weight, or 3% by weight or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

(b) 3,3'-dicarboxybiphenyl in an amount ranging from 20 ppm to 150 ppm, or ranging from 25 ppm to 100 ppm, or ranging from 25 ppm to 75 ppm, or ranging from 200 ppm, or 300 ppm, or 500 ppm and 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2% by weight, or 3% by weight, or 5% by weight, or 10% by weight , or 25% by weight, or 49% by weight;

VIII. In one embodiment of the invention, dry carboxylic acid composition 280 comprises:

(1) Isophthalic acid in an amount greater than 50 percent by weight, or greater than 60 percent by weight, or greater than 70 percent by weight, or greater than 80 percent by weight, or greater than 90 percent by weight, or greater than 95 percent by weight, or greater than 97 percent or greater than 98 percent or greater than 98.5 percent or greater than 99 percent, or greater than 99.5 percent by weight;

and (2) (a) 3-carboxybenzaldehyde (3-CBA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging between 1 ppm and 125 ppm; or (b) m-toluic acid (m-TA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm and 125 ppm; or (c) both of the following:

ES 2 688 198 T3 (1) 3-carboxybenzaldehyde (3-CBA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging between 1 ppm and 125 ppm;

(2) m-toluic acid (m-TA) in an amount ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

where the total concentration of 3-CBA and m-TA ranges between 1 ppm and 2000 ppm, 1 ppm and 1000 ppm, or between 1 ppm and 500 ppm, or between 1 ppm and 250 ppm, or between 1 ppm and 125 ppm;

^Y (3) both of the following:

(a) Benzene-tricarboxylic acid isomers ranging from 140 ppm to 1000 ppm, or ranging from 175 ppm to 750 ppm, or ranging from 200 ppm to 500 ppm, or ranging from 150 ppm, or 175 ppm, or 200 ppm and 500 ppm, or 750 ppm, or 1000 ppm;

(b) 3,3'-dicarboxybiphenyl in an amount ranging from 20 ppm to 150 ppm, or ranging from 25 ppm to 100 ppm, or ranging from 25 ppm to 75 ppm, or ranging from 200 ppm, or 300 ppm, or 500 ppm and 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2% by weight, or 3% by weight, or 5% by weight, or 10% by weight , or 25% by weight, or 49% by weight;

IX. In another embodiment of the invention, the dry carboxylic acid composition 280 comprises:

(1) Isophthalic acid in an amount greater than 50 percent by weight, or greater than 60 percent by weight, or greater than 70 percent by weight, or greater than 80 percent by weight, or greater than 90 percent by weight, or greater than 95 percent by weight, or greater than 97 percent or greater than 98 percent or greater than 98.5 percent or greater than 99 percent, or greater than 99.5 percent by weight; and (2) 3-carboxybenzaldehyde (3-CBA) in an amount ranging from 1 ppm to 500 ppm, and (3) all of the following:

(a) Terephthalic acid in an amount of at least 50 ppm, or ranging from 50 ppm to 2000 ppm, or ranging from 75 ppm to 1500 ppm, or ranging from 100 ppm to 1000 ppm, or ranging from 150 ppm and 500 ppm, or ranging between 50 ppm, or 75 ppm, or 100 ppm, or 150 ppm and 500 ppm, or 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2 % by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight, or ranging between 500 ppm, or 1000 ppm and 2000 ppm, or 0.5% by weight or 1% by weight, or 2% by weight, or 3% by weight or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

(b) Benzene tricarboxylic acid isomers ranging from 140 ppm to 1000 ppm, or ranging from 175 ppm to 750 ppm, or ranging from 200 ppm to 500 ppm, or ranging from 150 ppm, or 175 ppm, or 200 ppm and 500 ppm, or 750 ppm, or 1000 ppm;

(c) 3,3'-dicarboxybiphenyl in an amount ranging from 20 ppm to 150 ppm, or ranging from 25 ppm to 100 ppm, or ranging from 25 ppm to 75 ppm, or ranging from 200 ppm, or 300 ppm, or 500 ppm and 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2% by weight, or 3% by weight, or 5% by weight, or 10% by weight , or 25% by weight, or 49% by weight;

Terephthalic Acid Compositions

I. In one embodiment of the invention, dry carboxylic acid composition 280 comprises:

(1) Terephthalic acid in an amount greater than 50 percent by weight, or greater than 60 percent by weight, or greater than 70 percent by weight, or greater than 80 percent by weight, or greater than 90 percent by weight, or greater than 95 percent by weight, or greater than 97 percent or greater than 98 percent or greater than 98.5 percent or greater than 99 percent, or greater than 99.5 percent by weight;

^Y (2) (a) 4-carboxybenzaldehyde (4-CBA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm and 125 ppm; or (b) p-toluic acid (p-TA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm and 125 ppm; or (c) both of the following:

ES 2 688 198 T3 (1) 4-carboxybenzaldehyde (4-CBA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging between 1 ppm and 125 ppm;

(2) p-toluic acid (p-TA) in an amount ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

where the total concentration of 4-CBA and p-TA ranges between 1 ppm and 2000 ppm, 1 ppm and 1000 ppm, or between 1 ppm and 500 ppm, or between 1 ppm and 250 ppm, or between 1 ppm and 125 ppm;

^Y (3) at least one, or at least two, or at least three, or at least four, or at least five, or at least six, or at least seven, or at least eight, or at least nine, or at least ten, or at least eleven, or at least twelve, or at least thirteen, or at least fourteen, or at least fifteen, or at least sixteen, or at least seventeen, or at least eighteen, or at least nineteen, or all following:

(a) Isophthalic acid in an amount of at least 50 ppm, or ranging from 50 ppm to 2000 ppm, or ranging from 75 ppm to 1500 ppm, or ranging from 100 ppm to 1000 ppm, or ranging from 150 ppm and 500 ppm;

(b) Phthalic acid in an amount of at least 20 ppm, or at least 50 ppm, or at least 100 ppm, or ranging from 20 ppm to 1000 ppm, or ranging from 50 ppm to 750 ppm, or ranging from 100 ppm and 500 ppm;

(c) trimellitic acid in an amount of at least 140 ppm, or ranging from 140 ppm to 1000 ppm, or ranging from 175 ppm to 750 ppm, or ranging from 200 ppm to 500 ppm;

(d) benzoic acid in an amount of at least 50 ppm, or at least 75 ppm, or at least 100 ppm; or ranging from 50 ppm to 500 ppm, or ranging from 75 ppm to 400 ppm, or ranging from 100 ppm to 300 ppm;

(e) 4-hydroxybenzoic acid in an amount of at least 3 ppm, at least 5 ppm, or at least 20 ppm, or ranging from 3 ppm to 200 ppm, or ranging from 5 ppm to 175 ppm, or ranging between 20 ppm and 150 ppm;

(f) 4-hydroxymethylbenzoic acid in an amount of at least 40 ppm, or at least 80 ppm, or at least 100 ppm, or ranging from 40 ppm to 200 ppm, or ranging from 80 ppm to 180 ppm, or ranges from 100 ppm to 160 ppm;

(g) 4,4'-dicarboxybiphenyl in an amount ranging from 20 ppm to 150 ppm, or ranging from 25 ppm to 100 ppm, or ranging from 25 ppm to 75 ppm;

(h) 2,6-dicarboxyanthraquinone in an amount less than 1 ppm, or less than 0.5 ppm, or less than 0.4 ppm, or less than 0.35 ppm;

(i) 4,4'-dicarboxystilbene in an amount greater than 7 ppm; or greater than 10 ppm;

(j) 2,5,4'-tricarboxybiphenyl in an amount ranging from 8 ppm to 100 ppm, or ranging from 9 ppm to 50 ppm, or ranging from 10 ppm to 25 ppm;

(k) 2,5,4'-tricarboxybenzophenone in an amount ranging from 5 ppm to 100 ppm, or ranging from 6 ppm to 75 ppm, or ranging from 7 ppm to 60 ppm;

(l) 4,4'-dicarboxybenzophenone in an amount ranging from 10 ppm to 150 ppm, or ranging from 12 ppm to 100 ppm, or ranging from 15 ppm to 75 ppm;

(m) 4,4'-dicarboxybenzyl in an amount ranging from 1 ppm to 30 ppm, or ranging from 2 ppm to 20 ppm, or ranging from 3 ppm to 10 ppm;

(n) form-acet-hydroxybenzoic acid in an amount ranging from 1 ppm to 20 ppm, or ranging from 2 ppm to 15 ppm, or ranging from 3 ppm to 10 ppm;

(o) acet-hydroxymethylbenzoic acid in an amount ranging from 1 ppm to 30 ppm, or ranging from 2 ppm to 20 ppm, or ranging from 3 ppm to 15 ppm;

(p) α-bromo-p-toluic acid in an amount ranging from 1 ppm to 100 ppm, or ranging from 2 ppm to 50 ppm, or ranging from 5 ppm to 25 ppm;

(q) bromo-benzoic acid in an amount ranging from 5 ppm to 50 ppm, or ranging from 10 ppm to 40 ppm, or ranging from 15 ppm to 35 ppm;

(r) bromo-acetic acid in an amount ranging from 1 ppm to 10 ppm;

(s) p-tolualdehyde in an amount ranging from 7 ppm to 50 ppm, or ranging from 8 ppm to 25 ppm, or ranging from 9 ppm to 20 ppm;

(t) terephthaldehyde in an amount ranging from 0.25 ppm to 10 ppm, or ranging from 0.5 ppm to 5 ppm, or ranging from 0.75 ppm to 2 ppm; and optionally, (4) at least one, or at least two, or at least three, or at least four, or at least five or at least six, or at least seven, or all of the following:

ES 2 688 198 T3 (a) isophthalic acid in an amount of at least 1 ppm, or ranging from 1 ppm to 5000 ppm, or ranging from 5 ppm to 2500 ppm, or ranging from 10 ppm to 2000 ppm, or ranging from 15 ppm to 1000 ppm, or ranging from 20 ppm to 500 ppm;

(b) phthalic acid in an amount of at least 1 ppm, or ranging from 1 ppm to 3000 ppm, or ranging from 2 ppm to 2000 ppm, or ranging from 3 ppm to 1000 ppm, or ranging from 4 ppm and 500 ppm;

(c) trimellitic acid in an amount of at least 1 ppm, or ranging from 1 ppm to 3000 ppm, or ranging from 5 ppm to 2000 ppm, or ranging from 10 ppm to 1000 ppm, or ranging from 20 ppm and 500 ppm;

(d) benzoic acid in an amount of at least 1 ppm, or ranging from 1 ppm to 3000 ppm, or ranging from 5 ppm to 2000 ppm, or ranging from 10 ppm to 1000 ppm, or ranging from 20 ppm and 500 ppm;

(e) 4-hydroxybenzoic acid in an amount of at least 1 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 5 ppm to 400 ppm, or ranging from 10 ppm to 200 ppm;

(f) 4-hydroxybenzoic acid in an amount of at least 1 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 5 ppm to 400 ppm, or ranging from 10 ppm to 200 ppm;

(g) 4,4'-dicarboxybiphenyl in an amount of at least 1 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 5 ppm to 400 ppm, or ranging from 10 ppm to 200 ppm;

(h) 2,6-dicarboxyanthraquinone in an amount of at least 0.1 ppm, or ranging from 0.1 ppm to 5 ppm, or ranging from 0.2 ppm to 4 ppm, or ranging from 0.3 ppm and 3 ppm; where the compound or compounds selected in (4) are different from the compound or compounds selected in (3).

II. In one embodiment of the invention, dry carboxylic acid composition 280 comprises:

(1) Terephthalic acid in an amount greater than 50 percent by weight, or greater than 60 percent by weight, or greater than 70 percent by weight, or greater than 80 percent by weight, or greater than 90 percent by weight, or greater than 95 percent by weight, or greater than 97 percent or greater than 98 percent or greater than 98.5 percent or greater than 99 percent, or greater than 99.5 percent by weight;

^Y (2) (a) 4-carboxybenzaldehyde (4-CBA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm and 125 ppm; or (b) p-toluic acid (p-TA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm and 125 ppm; or (c) both of the following:

(1) 4-carboxybenzaldehyde (4-CBA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

(2) p-toluic acid (p-TA) in an amount ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

where the total concentration of 4-CBA and p-TA ranges between 1 ppm and 2000 ppm, 1 ppm and 1000 ppm, or between 1 ppm and 500 ppm, or between 1 ppm and 250 ppm, or between 1 ppm and 125 ppm;

^Y (3) at least two, or at least three, or at least four, or at least five or at least six, or all of the following:

(a) Isophthalic acid in an amount of at least 50 ppm, or ranging from 50 ppm to 2000 ppm, or ranging from 75 ppm to 1500 ppm, or ranging from 100 ppm to 1000 ppm, or ranging from 150 ppm and 500 ppm, or ranging between 50 ppm, or 75 ppm, or 100 ppm, or 150 ppm and 500 ppm, or 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2 % by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight, or ranging between 500 ppm, or 1000 ppm and 2000 ppm, or 0.5% by weight or 1% by weight, or 2% by weight, or 3% by weight or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

ES 2 688 198 T3 (b) trimellitic acid ranging from 140 ppm to 1000 ppm, or ranging from 175 ppm to 750 ppm, or ranging from 200 ppm to 500 ppm, or ranging from 150 ppm, or 175 ppm, or 200 ppm and 500 ppm, or 750 ppm, or 1000 ppm;

(c) 4,4'-dicarboxybiphenyl in an amount ranging from 20 ppm to 150 ppm, or ranging from 25 ppm to 100 ppm, or ranging from 25 ppm to 75 ppm, or ranging from 200 ppm, or 300 ppm, or 500 ppm and 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2% by weight, or 3% by weight, or 5% by weight, or 10% by weight , or 25% by weight, or 49% by weight;

(d) phthalic acid in an amount of at least 20 ppm, or at least 50 ppm, or at least 100 ppm, or ranging from 20 ppm to 1000 ppm, or ranging from 50 ppm to 750 ppm, or ranging from 100 ppm and 500 ppm, or ranging between 20 ppm, 50 ppm, 100 ppm and 500 ppm, or 750 ppm, or 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2 % by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight, or ranging between 500 ppm, or 750 ppm, or 1000 ppm and 2000 ppm, or 0.5% by weight or 1% by weight, or 2% by weight, or 3% by weight or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

(e) 4-hydroxybenzoic acid ranging from 3 ppm to 200 ppm, or ranging from 5 ppm to 175 ppm, or ranging from 20 ppm to 150 ppm, or ranging from 3 ppm, or 5 ppm, or 20 ppm and 150 ppm, or 175 ppm, or 200 ppm, or 500 ppm, or 1000 ppm;

(f) 4-hydroxymethylbenzoic acid in an amount of at least 40 ppm, or at least 80 ppm, or at least 100 ppm, or ranging from 40 ppm to 200 ppm, or ranging from 80 ppm to 180 ppm, or ranges from 100 ppm to 160 ppm, or ranges from 40 ppm, or 80 ppm, or 100 ppm to 500 ppm, or 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2% by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

(g) benzoic acid ranging from 60 ppm to 500 ppm, or ranging from 75 ppm to 400 ppm, or ranging from 100 ppm to 300 ppm, or ranging from 60 ppm, or 75 ppm, or 100 ppm to 300 ppm, or 500 ppm, or 1000 ppm;

III. In one embodiment of the invention, dry carboxylic acid composition 280 comprises:

(1) Terephthalic acid in an amount greater than 50 percent by weight, or greater than 60 percent by weight, or greater than 70 percent by weight, or greater than 80 percent by weight, or greater than 90 percent by weight, or greater than 95 percent by weight, or greater than 97 percent or greater than 98 percent or greater than 98.5 percent or greater than 99 percent, or greater than 99.5 percent by weight;

^Y (2) (a) 4-carboxybenzaldehyde (4-CBA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm and 125 ppm; or (b) p-toluic acid (p-TA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm and 125 ppm; or (c) both of the following:

(1) 4-carboxybenzaldehyde (4-CBA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

(2) p-toluic acid (p-TA) in an amount ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

where the total concentration of 4-CBA and p-TA ranges between 1 ppm and 2000 ppm, 1 ppm and 1000 ppm, or between 1 ppm and 500 ppm, or between 1 ppm and 250 ppm, or between 1 ppm and 125 ppm;

^Y (3) at least two, or at least three, or at least four, or all of the following:

(a) Isophthalic acid in an amount of at least 50 ppm, or ranging from 50 ppm to 2000 ppm, or ranging from 75 ppm to 1500 ppm, or ranging from 100 ppm to 1000 ppm, or ranging from 150 ppm and 500 ppm, or ranging between 50 ppm, or 75 ppm, or 100 ppm, or 150 ppm and 500 ppm, or 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2 % by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight, or ranging between 500 ppm, or 1000 ppm and 2000 ppm, or 0.5% by weight or 1% by weight, or 2% by weight, or 3% by weight or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

ES 2 688 198 T3 (b) trimellitic acid ranging from 140 ppm to 1000 ppm, or ranging from 175 ppm to 750 ppm, or ranging from 200 ppm to 500 ppm, or ranging from 150 ppm, or 175 ppm, or 200 ppm and 500 ppm, or 750 ppm, or 1000 ppm;

(c) 4,4'-dicarboxybiphenyl in an amount ranging from 20 ppm to 150 ppm, or ranging from 25 ppm to 100 ppm, or ranging from 25 ppm to 75 ppm, or ranging from 200 ppm, or 300 ppm, or 500 ppm and 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2% by weight, or 3% by weight, or 5% by weight, or 10% by weight , or 25% by weight, or 49% by weight;

(d) phthalic acid in an amount of at least 20 ppm, or at least 50 ppm, or at least 100 ppm, or ranging from 20 ppm to 1000 ppm, or ranging from 50 ppm to 750 ppm, or ranging from 100 ppm and 500 ppm, or ranging between 20 ppm, 50 ppm, 100 ppm and 500 ppm, or 750 ppm, or 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2 % by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight, or ranging between 500 ppm, or 750 ppm, or 1000 ppm and 2000 ppm, or 0.5% by weight or 1% by weight, or 2% by weight, or 3% by weight or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

(e) benzoic acid ranging from 60 ppm to 500 ppm, or ranging from 75 ppm to 400 ppm, or ranging from 100 ppm to 300 ppm, or ranging from 60 ppm, or 75 ppm, or 100 ppm to 300 ppm, or 500 ppm, or 1000 ppm;

IV. In one embodiment of the invention, dry carboxylic acid composition 280 comprises:

(1) Terephthalic acid in an amount greater than 50 percent by weight, or greater than 60 percent by weight, or greater than 70 percent by weight, or greater than 80 percent by weight, or greater than 90 percent by weight, or greater than 95 percent by weight, or greater than 97 percent or greater than 98 percent or greater than 98.5 percent or greater than 99 percent, or greater than 99.5 percent by weight;

^Y (2) (a) 4-carboxybenzaldehyde (4-CBA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm and 125 ppm; or (b) p-toluic acid (p-TA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm and 125 ppm; or (c) both of the following:

(1) 4-carboxybenzaldehyde (4-CBA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

(2) p-toluic acid (p-TA) in an amount ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

where the total concentration of 4-CBA and p-TA ranges between 1 ppm and 2000 ppm, 1 ppm and 1000 ppm, or between 1 ppm and 500 ppm, or between 1 ppm and 250 ppm, or between 1 ppm and 125 ppm;

^Y (3) at least two, or at least three, or all of the following:

(a) Isophthalic acid in an amount of at least 50 ppm, or ranging from 50 ppm to 2000 ppm, or ranging from 75 ppm to 1500 ppm, or ranging from 100 ppm to 1000 ppm, or ranging from 150 ppm and 500 ppm, or ranging between 50 ppm, or 75 ppm, or 100 ppm, or 150 ppm and 500 ppm, or 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2 % by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight, or ranging between 500 ppm, or 1000 ppm and 2000 ppm, or 0.5% by weight or 1% by weight, or 2% by weight, or 3% by weight or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

(b) trimellitic acid ranging from 140 ppm to 1000 ppm, or ranging from 175 ppm to 750 ppm, or ranging from 200 ppm to 500 ppm, or ranging from 150 ppm, or 175 ppm, or 200 ppm to 500 ppm, or 750 ppm, or 1000 ppm;

(c) 4,4'-dicarboxybiphenyl in an amount ranging from 20 ppm to 150 ppm, or ranging from 25 ppm to 100 ppm, or ranging from 25 ppm to 75 ppm, or ranging from 200 ppm, or 300 ppm, or 500 ppm and 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2% by weight, or 3% by weight, or 5% by weight, or 10% by weight , or 25% by weight, or 49% by weight;

ES 2 688 198 T3 (d) phthalic acid in an amount of at least 20 ppm, or at least 50 ppm, or at least 100 ppm, or ranging from 20 ppm to 1000 ppm, or ranging from 50 ppm to 750 ppm , or ranging from 100 ppm to 500 ppm, or ranging from 20 ppm, 50 ppm, 100 ppm and 500 ppm, or 750 ppm, or 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2% by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight, or ranging between 500 ppm, or 750 ppm, or 1000 ppm and 2000 ppm, or 0.5% by weight or 1% by weight, or 2% by weight, or 3% by weight or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

V. In one embodiment of the invention, the dry carboxylic acid composition 280 comprises:

(1) Terephthalic acid in an amount greater than 50 percent by weight, or greater than 60 percent by weight, or greater than 70 percent by weight, or greater than 80 percent by weight, or greater than 90 percent by weight, or greater than 95 percent by weight, or greater than 97 percent or greater than 98 percent or greater than 98.5 percent or greater than 99 percent, or greater than 99.5 percent by weight;

^Y (2) (a) 4-carboxybenzaldehyde (4-CBA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm and 125 ppm; or (b) p-toluic acid (p-TA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm and 125 ppm; or (c) both of the following:

(1) 4-carboxybenzaldehyde (4-CBA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

(2) p-toluic acid (p-TA) in an amount ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

where the total concentration of 4-CBA and p-TA ranges between 1 ppm and 2000 ppm, 1 ppm and 1000 ppm, or between 1 ppm and 500 ppm, or between 1 ppm and 250 ppm, or between 1 ppm and 125 ppm;

^Y (3) at least two or all of the following:

(a) Isophthalic acid in an amount of at least 50 ppm, or ranging from 50 ppm to 2000 ppm, or ranging from 75 ppm to 1500 ppm, or ranging from 100 ppm to 1000 ppm, or ranging from 150 ppm and 500 ppm, or ranging between 50 ppm, or 75 ppm, or 100 ppm, or 150 ppm and 500 ppm, or 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2 % by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight, or ranging between 500 ppm, or 1000 ppm and 2000 ppm, or 0.5% by weight or 1% by weight, or 2% by weight, or 3% by weight or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

(b) trimellitic acid ranging from 140 ppm to 1000 ppm, or ranging from 175 ppm to 750 ppm, or ranging from 200 ppm to 500 ppm, or ranging from 150 ppm, or 175 ppm, or 200 ppm to 500 ppm, or 750 ppm, or 1000 ppm;

(c) 4,4'-dicarboxybiphenyl in an amount ranging from 20 ppm to 150 ppm, or ranging from 25 ppm to 100 ppm, or ranging from 25 ppm to 75 ppm, or ranging from 200 ppm, or 300 ppm, or 500 ppm and 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2% by weight, or 3% by weight, or 5% by weight, or 10% by weight , or 25% by weight, or 49% by weight;

SAW. In one embodiment of the invention, dry carboxylic acid composition 280 comprises:

(1) Terephthalic acid in an amount greater than 50 percent by weight, or greater than 60 percent by weight, or greater than 70 percent by weight, or greater than 80 percent by weight, or greater than 90 percent by weight, or greater than 95 percent by weight, or greater than 97 percent or greater than 98 percent or greater than 98.5 percent or greater than 99 percent, or greater than 99.5 percent by weight;

^Y (2)

ES 2 688 198 T3 (a) 4-carboxybenzaldehyde (4-CBA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranges from 1 ppm to 125 ppm; or (b) p-toluic acid (p-TA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm and 125 ppm; or (c) both of the following:

(1) 4-carboxybenzaldehyde (4-CBA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

(2) p-toluic acid (p-TA) in an amount ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

where the total concentration of 4-CBA and p-TA ranges between 1 ppm and 2000 ppm, 1 ppm and 1000 ppm, or between 1 ppm and 500 ppm, or between 1 ppm and 250 ppm, or between 1 ppm and 125 ppm;

^Y (3) both of the following:

(a) Isophthalic acid in an amount of at least 50 ppm, or ranging from 50 ppm to 2000 ppm, or ranging from 75 ppm to 1500 ppm, or ranging from 100 ppm to 1000 ppm, or ranging from 150 ppm and 500 ppm, or ranging between 50 ppm, or 75 ppm, or 100 ppm, or 150 ppm and 500 ppm, or 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2 % by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight, or ranging between 500 ppm, or 1000 ppm and 2000 ppm, or 0.5% by weight or 1% by weight, or 2% by weight, or 3% by weight or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

(b) trimellitic acid ranging from 140 ppm to 1000 ppm, or ranging from 175 ppm to 750 ppm, or ranging from 200 ppm to 500 ppm, or ranging from 150 ppm, or 175 ppm, or 200 ppm to 500 ppm, or 750 ppm, or 1000 ppm;

VII. In one embodiment of the invention, dry carboxylic acid composition 280 comprises:

(1) Terephthalic acid in an amount greater than 50 percent by weight, or greater than 60 percent by weight, or greater than 70 percent by weight, or greater than 80 percent by weight, or greater than 90 percent by weight, or greater than 95 percent by weight, or greater than 97 percent or greater than 98 percent or greater than 98.5 percent or greater than 99 percent, or greater than 99.5 percent by weight;

^Y (2) (a) 4-carboxybenzaldehyde (4-CBA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm and 125 ppm; or (b) p-toluic acid (p-TA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm and 125 ppm; or (c) both of the following:

(1) 4-carboxybenzaldehyde (4-CBA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

(2) p-toluic acid (p-TA) in an amount ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

where the total concentration of 4-CBA and p-TA ranges between 1 ppm and 2000 ppm, 1 ppm and 1000 ppm, or between 1 ppm and 500 ppm, or between 1 ppm and 250 ppm, or between 1 ppm and 125 ppm;

^Y (3) both of the following:

(a) Isophthalic acid in an amount of at least 50 ppm, or ranging from 50 ppm to 2000 ppm, or ranging from 75 ppm to 1500 ppm, or ranging from 100 ppm to 1000 ppm, or ranging from 150 ppm and 500 ppm, or ranging between 50 ppm, or 75 ppm, or 100 ppm, or 150 ppm and 500 ppm, or 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2 % by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight, or that

ES 2 688 198 T3 ranges from 500 ppm, or 1000 ppm to 2000 ppm, or 0.5% by weight, or 1% by weight, or 2% by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

(b) 4,4'-dicarboxybiphenyl in an amount ranging from 20 ppm to 150 ppm, or ranging from 25 ppm to 100 ppm, or ranging from 25 ppm to 75 ppm, or ranging from 200 ppm, or 300 ppm, or 500 ppm and 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2% by weight, or 3% by weight, or 5% by weight, or 10% by weight , or 25% by weight, or 49% by weight;

VIII. In one embodiment of the invention, dry carboxylic acid composition 280 comprises:

(1) Terephthalic acid in an amount greater than 50 percent by weight, or greater than 60 percent by weight, or greater than 70 percent by weight, or greater than 80 percent by weight, or greater than 90 percent by weight, or greater than 95 percent by weight, or greater than 97 percent or greater than 98 percent or greater than 98.5 percent or greater than 99 percent, or greater than 99.5 percent by weight;

^Y (2) (a) 4-carboxybenzaldehyde (4-CBA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm and 125 ppm; or (b) p-toluic acid (p-TA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm and 125 ppm; or (c) both of the following:

(1) 4-carboxybenzaldehyde (4-CBA) in an amount ranging from 1 ppm to 1000 ppm, or ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

(2) p-toluic acid (p-TA) in an amount ranging from 1 ppm to 500 ppm, or ranging from 1 ppm to 250 ppm, or ranging from 1 ppm to 125 ppm;

where the total concentration of 4-CBA and p-TA ranges between 1 ppm and 2000 ppm, 1 ppm and 1000 ppm, or between 1 ppm and 500 ppm, or between 1 ppm and 250 ppm, or between 1 ppm and 125 ppm;

^Y (3) both of the following:

(a) trimellitic acid ranging from 140 ppm to 1000 ppm, or ranging from 175 ppm to 750 ppm, or ranging from 200 ppm to 500 ppm, or ranging from 150 ppm, or 175 ppm, or 200 ppm to 500 ppm, or 750 ppm, or 1000 ppm;

(b) 4,4'-dicarboxybiphenyl in an amount ranging from 20 ppm to 150 ppm, or ranging from 25 ppm to 100 ppm, or ranging from 25 ppm to 75 ppm, or ranging from 200 ppm, or 300 ppm, or 500 ppm and 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2% by weight, or 3% by weight, or 5% by weight, or 10% by weight , or 25% by weight, or 49% by weight;

IX. In another embodiment of the invention, the dry carboxylic acid composition 280 comprises:

(1) Terephthalic acid in an amount greater than 50 percent by weight, or greater than 60 percent by weight, or greater than 70 percent by weight, or greater than 80 percent by weight, or greater than 90 percent by weight, or greater than 95 percent by weight, or greater than 97 percent or greater than 98 percent or greater than 98.5 percent or greater than 99 percent, or greater than 99.5 percent by weight; and (2) 4-carboxybenzaldehyde (4-CBA) in an amount ranging from 1 ppm to 500 ppm, and (3) all of the following:

(a) Isophthalic acid in an amount of at least 50 ppm, or ranging from 50 ppm to 2000 ppm, or ranging from 75 ppm to 1500 ppm, or ranging from 100 ppm to 1000 ppm, or ranging from 150 ppm and 500 ppm, or ranging between 50 ppm, or 75 ppm, or 100 ppm, or 150 ppm and 500 ppm, or 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2 % by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight, or ranging between 500 ppm, or 1000 ppm and 2000 ppm, or 0.5% by weight or 1% by weight, or 2% by weight, or 3% by weight or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

(b) trimellitic acid ranging from 140 ppm to 1000 ppm, or ranging from 175 ppm to 750 ppm, or ranging from 200 ppm to 500 ppm, or ranging from 150 ppm, or 175 ppm, or 200 ppm to 500 ppm, or 750 ppm, or 1000 ppm;

ES 2 688 198 T3 (c) 4,4'-dicarboxybiphenyl in an amount ranging from 20 ppm to 150 ppm, or ranging from 25 ppm to 100 ppm, or ranging from 25 ppm to 75 ppm, or ranging from 200 ppm, or 300 ppm, or 500 ppm and 1000 ppm, or 2000 ppm, or 0.5% by weight, or 1% by weight, or 2% by weight, or 3% by weight, or 5% by weight, or 10% by weight, or 25% by weight, or 49% by weight;

In another embodiment of the invention, all of the dry carboxylic acid composition 280 compositions noted above further comprise a catalyst composition of less than 1000 ppm, or 500 ppm, or 250 ppm, or 100 ppm. Other ranges are less than 85 ppm and less than 50 ppm. However, another range is less than 25 ppm, or less than 15 ppm, or less than 10 ppm, or less than 5 ppm. In another embodiment of the invention, the catalyst comprises cobalt and manganese. In another embodiment of the invention, the catalyst comprises cobalt.

All concentrations throughout the disclosure and claims are on a dry solids basis. The physical form of the TPA product can be a dry solid, wet cake, paste or suspension. For the sake of consistency, any liquid present in the TPA product is ignored when describing its composition. The composition will be expressed as a percentage by weight or ppmp (part per million by weight) on a dry solids basis assuming there is no moisture in the product. For example, 500 ppmw of p-toluic acid in a TPA product means that there are 500 grams of p-toluic acid per 1,000,000 grams of non-liquid mass in the product, regardless of the actual physical form of the product. All measurements expressed in ppm are ppm by weight. Therefore, ppm is equivalent to ppmp throughout the disclosure.

In another embodiment of the invention, all of the compositions listed above are an average composition over a continuous period during steady state operation. In yet another embodiment of the invention, the compositions disclosed above are the time-average compositions obtained over a period of 7 days, or a period of 14 days, or a period of 30 days during continuous operation. In another embodiment of the invention, the compositions disclosed above could include any sample taken from a batch of 1 metric ton (1,000 kg) or more. In another embodiment of the invention, the compositions disclosed above could include any sample in a shipping container, or a shipping container containing at least 500 kg of the disclosed compositions.

In one embodiment of the invention, the compositions of matter that the investigators have specified will be used to make PET that could subsequently be used to produce coatings, resins, fibers, a film, sheet, containers, or other shaped articles.

In one embodiment of the invention, the compositions disclosed above may have functionalities in PET polymerization ranging from zero to at least three. Functional groups for the polycondensation polymerization of polyesters and copolyesters, as well as polyamides, copolyamides, and other copolycondensation polymers comprise reactive carboxyl and reactive hydroxyl groups. The following discussion will focus on the impact of various impurities or oxidation by-products on the manufacturing and properties of polyethylene terephthalate (PET) as an example.

Zero functional impurities are removed by purge procedures in PET manufacture or end up as diluent species in PET. The mono and trifunctional species affect the polymerization rate, possibly both in the melt phase and in the solid state, but generally more in the solid state due to the difficulty to obtain high molecular weight especially with monofunctional chain terminator species present. Depending on the concentrations, the mono and trifunctional species can also affect the properties of the PET product by changing the PET polydispersity of the molecular weight.

For example, p-toluic acid (p-TA) is an impurity that is monofunctional in the polymerization of PET with PET process polymerization catalysts. In contrast, 4-carboxybenzaldehyde (4-CBA) is monofunctional when used with an Sb (antimony) catalyst in PET polymerization, but can be di- or trifunctional when used with a Ti (titanium) catalyst in the polymerization of PET, due to the conversion of the aldehyde group into a hemi-acetal or an acetal. Trimellitic acid (1,2,4-benzene tricarboxylic acid or TMA) is a trifunctional impurity. In a first approximation, mono and trifunctional impurities have compensating effects on PET polymerization. That is, higher amounts of monofunctional impurities, such as p-toluic acid, benzoic acid, monocarboxyfluorenones, bromo-benzoic acid, bromo-acetic acid and 4-CBA (with Sb catalyst), can be compensated through a higher concentration of tri- or major impurities

ES 2 688 198 T3 functional, such as trimellitic acid, 2,5,4'-tricarboxybiphenyl, 2,5,4'-tricarboxybenzophenone and 4-CBA (with Ti catalyst). Molar concentrations and not weight-based concentrations should be used when comparing the polymerization effects of impurities with functionality other than two, as well as the relative reactivity of the reacting groups (mainly carboxyl functionality) when the functionality is greater than one. Fortunately, most of the impurities present in PTA in significant concentrations (more than a few ppmp) are bifunctional and therefore have no deleterious effects on PET polymerization due to their functionality and have no deleterious effects on PET polymer properties due to their functionality. at its low concentration. In particular, assuming an Sb-catalyzed PET polymerization process, then each 1.0 ppmw of TMA will offset about about 0.60 ppmw of benzoic acid (BA), or 0.65 ppmw of p-TA, due to differences in molecular weight. If analytical information on PTA impurities is known, that is, the concentrations of the impurities and their functionalities, then an estimate of the overall relative effect on PET polymerization can be made.

Note that for IPA instead of TPA the compounds will be 3-hydroxybenzoic acid, 3-hydroxymethylbenzoic acid, 3,3'-dicarboxybiphenyl, isomers of dicarboxyanthraquinone and 3,3'-dicarboxystilbene, etc. Similarly, for carboxylic acids, the compounds will be hydroxybenzoic acid isomers, hydroxymethylbenzoic acid isomers, dicarboxybiphenyl isomers, dicarboxyanthraquinone isomers and dicarboxystilbene isomers, etc.

In another embodiment of the invention, the above-disclosed carboxylic acid compositions comprising terephthalic or isophthalic acid or any difunctional carboxylic acid would have a total concentration of monofunctional compound (s) of less than 0.5 mole%, or less than 0.25%. molar, or less than 0.1% molar, or less than 0.05% molar, or less than 0.025% molar, or less than 0.01% molar, or less than 0.005% molar.

In another embodiment of the invention, the previously disclosed carboxylic acid compositions comprising terephthalic or isophthalic acid or any difunctional carboxylic acid would have a total concentration of monofunctional compound (s) of less than 5000 ppm, or less than 2500 ppm, or less than 1000. ppm, or less than 500 ppm, or less than 250 ppm, or less than 100 ppm, or less than 50 ppm.

In another embodiment of the invention, the above-disclosed carboxylic acid compositions comprising terephthalic or isophthalic acid or any difunctional carboxylic acid would have a total concentration of trifunctional and greater than trifunctional compound (s) of less than 0.5 mol%, or less than 0.25 mole%, or less than 0.1 mole%, or less than 0.05 mole%, or less than 0.025 mole%, or less than 0.01 mole%, or less than 0.005 mole%.

In another embodiment of the invention, the above-disclosed carboxylic acid compositions comprising terephthalic or isophthalic acid or any difunctional carboxylic acid would have a total concentration of trifunctional and greater than trifunctional compound (s) of less than 5000 ppm, or less than 2500 ppm, or less than 1000 ppm, or less than 500 ppm, or less than 250 ppm, or less than 100 ppm, or less than 50 ppm.

In another embodiment of the invention, the above-disclosed carboxylic acid compositions comprising terephthalic or isophthalic acid or any difunctional carboxylic acid would have a total concentration of zero-functional compound (s) of less than 0.5 mole%, or less than 0, 25% molar, or less than 0.1% molar, or less than 0.05% molar, or less than 0.025% molar, or less than 0.01% molar, or less than 0.005% molar.

In another embodiment of the invention, the above-disclosed carboxylic acid compositions comprising terephthalic or isophthalic acid or any difunctional carboxylic acid would have a total concentration of zero-functional compound (s) of less than 5000 ppm, or less than 2500 ppm, or less. at 1000 ppm, or less than 500 ppm, or less than 250 ppm, or less than 100 ppm, or less than 50 ppm.

In another embodiment of the invention, the above-disclosed carboxylic acid compositions comprising terephthalic or isophthalic acid or any difunctional carboxylic acid would have an average functionality, excluding zero-functional species, of at least 1,995 or greater, or at least 1,996 or greater. , or at least 1,997 or greater, or at least 1,998 or greater, or at least 1,999 or greater, or at least 1,9995 or greater, or at least 1,9999 or greater.

In another embodiment of the invention, the previously disclosed carboxylic acid compositions comprising terephthalic or isophthalic acid or any difunctional carboxylic acid would have average functionality,

ES 2 688 198 T3 not including species with zero functionality, between 1,995, or 1,996, or 1,997, or 1,998, or 1,999, or 1,9995, or 1,9999 and

2,0000, or 2,0001, or 2,0005, or 2,001, or 2,002 or 2,003, or 2,004, or 2,005.

In another embodiment of the invention, the above-disclosed carboxylic acid compositions comprising terephthalic or isophthalic acid or any difunctional carboxylic acid would have a medium carboxyl functionality, excluding zero carboxyl functional species, of at least 1,995 or greater, or at least 1,996 or greater, or at least 1,997 or greater, or at least 1,998 or greater, or at least 1,999 or greater, or at least 1,9995 or greater, or at least 1,9999 or greater.

In another embodiment of the invention, the above-disclosed carboxylic acid compositions comprising terephthalic or isophthalic acid or any difunctional carboxylic acid would have average carboxyl functionality, excluding zero-functional species, of between 1,995, or 1,996, or 1,997, or 1,998 , or 1,999, or 1,9995, or 1,9999 and 2,0000, or 2,0001, or 2,0005, or 2,001, or 2,002 or 2,003, or 2,004, or 2,005.

In another embodiment of the invention, a process is provided for producing an enriched composition 240 as shown in Figures 20A and 20B. In this embodiment of the invention, as shown in Figures 20 a and b, catalyst removal zone 180 is optional and enrichment zone 210 is required. All zones in Figures 20 A and B have been previously described herein. divulgation. It should be appreciated that the process zones described above can be used in any other logical order to produce the dry carboxylic acid composition 280. It should also be appreciated that when the process zones are rearranged, the process conditions can change. It should also be appreciated that the procedure areas can be used independently.

In another embodiment of the invention, each embodiment may optionally include a further step comprising decolorizing the carboxylic acid or an esterified carboxylic acid. Preferably, the decolorization is carried out by hydrogenation. Discoloration can occur at any location after primary oxidation zone 20.

The decolorization of a carboxylic acid suspension or an esterified carboxylic acid can be carried out by any means known in the art and is not limited to hydrogenation. However, for example in one embodiment of the invention, decolorization can be accomplished by reacting a carboxylic acid that has undergone an esterification treatment, for example with ethylene glycol, with molecular hydrogen in the presence of a hydrogenation catalyst in a bleaching reactor zone to produce bleached carboxylic acid solution or bleached ester product. For the bleaching reactor zone, there are no special limitations on the shape or construction thereof, subject to an arrangement that allows the supply of hydrogen to make an intimate contact of the carboxylic acid or ester product with the catalyst in the bleaching reactor zone. . Typically, the hydrogenation catalyst is generally a single Group VIII metal or a combination of Group VIII metals. Preferably, the hydrogenation catalyst is selected from a group consisting of palladium, ruthenium, rhodium, and a combination thereof. The decolorizing reactor zone comprises a hydrogenation reactor operating at a temperature and pressure sufficient to hydrogenate a portion of the characteristically yellow compounds to colorless derivatives.

In another embodiment of the invention, instead of utilizing the drying zone as preciously disclosed, the enriched composition 240 can be routed directly to an esterification zone 310 as shown in Figure 16. In this embodiment, the moisture content in the enriched composition 240 is predominantly water and the% by weight of acetic acid in the enriched composition 240 is less than 10%, preferably less than 2%, and most preferably less than 0, 1 %. "Predominantly" as used in this invention means greater than 85 mass% total moisture.

Therefore, rather than drying, in one embodiment, step (i) comprises adding a diol in conduit 600 to enriched composition 240 in an esterification reactor zone 610 to remove a portion of the moisture through conduit. 620 to form a carboxylic acid and diol mixture in the esterification reactor zone 610. The carboxylic acid and diol react to form a hydroxyalkyl ester stream 630. Hydroxyalkyl ester stream 630 comprises a hydroxyalkyl ester compound.

The diol into conduit 600 is introduced in such a way that it displaces moisture as the dominant suspending liquid. This can be accomplished by introducing a diol through conduit 600 as a saturated liquid in

ES 2 688 198 T3 a temperature range from about 150 ° C to about 300 ° C. Preferably, the diol into conduit 600 is introduced as a saturated or superheated vapor in a temperature range from about 150 ° C to about 300 ° C in a form with sufficient enthalpy to evaporate the water, exiting through conduit 320 . The diol in conduit 600 is selected from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 1,3-butanediol, cyclohexanedimethanol, neopentyl glycol, others diols useful in the manufacture of polyesters and copolyesters, and mixtures thereof. Preferably, the diol in conduit 600 is ethylene glycol. Alternatively, an external heat source can be used to introduce enough enthalpy to vaporize the water, which exits through conduit 620. The hydroxyalkyl ester stream mixture exits via conduit stream 630.

The esterification reactor zone 610 operates at a temperature of about 240 ° C or higher. Preferably, the esterification reactor zone 610 operates in a temperature range of from about 260 ° C to about 280 ° C. The esterification reactor zone 610 is operated at a pressure of from about 40 psia to about 100 psia to effect the esterification of the terephthalic acid and the diol mixture to produce a hydroxyethyl ester of terephthalic acid.

In another embodiment of the invention, instead of utilizing the drying zone as preciously disclosed, the enriched composition 240 can be routed directly to a liquid exchange zone 500 as shown in Figure 17. In this embodiment, the moisture content in the enriched composition 240 has a significant amount of solvent. "Significant amount" as used in this invention means more than 1%, or more than 2%, or more than 5% or more than 10% or more than 15%.

The enriched composition 240 is subjected to an exchange solvent wash or "rinse" in the liquid exchange zone 500, where a portion of the initial solvent is replaced with exchange solvent to form an exchange solvent enriched composition 246. Exchange solvent comprises water, methanol, ethylene glycol and any diol or monomer compatible with the polyester or copolyester manufacturing process. The exchange solvent-enriched composition 246 is preferably in the range of 0.5-30% by weight moisture, more preferably in the range of about 1-20% by weight moisture, and most preferably in the range of 1 -5% moisture by weight. The residual moisture of the exchange solvent-enriched composition 206 could contain less than about 2% by weight of solvent, another range is less than 5% or less than 10% by weight, or less than 20%.

In one embodiment of the invention, the exchange solvent is introduced into the liquid exchange zone 500. The exchange solvent is preferably introduced continuously. There are no limitations on the temperature or pressure of the exchange solvent, including the use of vaporized water, steam, or a combination of water and steam as a wash.

The liquid exchange zone 500 comprises at least one solid liquid separation device. The solid liquid separation device may comprise typically, but not limited to, the following types of devices: centrifuges, cyclones, rotary drum filters, belt filters, press filters, etc. The solid liquid separation device can operate within a temperature range of about 5 ° C to 195 ° C. The liquid exchange zone and the catalyst removal zone can be within the same device, for example in a belt filter. The exchange solvent-enriched composition 246 is subsequently sent to an esterification zone 610 described above.

EXAMPLES

An embodiment of this invention may be further illustrated by the following examples of preferred embodiments thereof, although it will be understood that these examples are included merely for purposes of illustration and are not intended to limit the scope.

PTA retention experiments

The objective of this set of experiments was to determine how the retention of IPA in the cooled carboxylic acid composition stream 170 varies with the wash temperature and the wash ratio of the wash feed stream 175 in the catalyst removal zone. 180. All experiments used an experimental scale Pannevis vacuum filtration apparatus. The carboxylic acid composition stream

The cooled ES 2 688 198 T3 170 was prepared by taking a suspension of the crystallized suspension composition 160 at 30 weight percent solids and evaporating the solvent to 50% solids. The suspension was then cooled to 30 ° C to generate a chilled carboxylic acid composition stream 170 and loaded onto the vacuum filter, and then washed with a wash feed stream 175. Both the wash ratio and the wash temperature were varied in the experiment. A wash ratio of 1 and 0.5 was used. A wash temperature of 90 ° C and 10 ° C was used. The wash was 90% acetic acid and 10% water. The time after adding the wash until the dry top of the cake was observed is called the top drying time and was recorded. Samples of the post-catalyst removal composition 200 were analyzed to determine the ppmp of IPA.

Experiment 1 (no washing)

700.10 g of the crystallized suspension composition stream 160 was charged into a stainless steel beaker. The suspension was heated until the weight of the suspension was reduced to 420 g. The suspension was quenched to 30 ° C using wet ice generating a chilled carboxylic acid composition stream 170. The cooled carboxylic acid composition stream 170 was fed to an experimental scale Pannevis vacuum filter. After feeding the cooled carboxylic acid composition stream 170 to the vacuum filter, 16.5 grams of the cooled carboxylic acid composition stream 170 remained in the steel beaker. The actual mass of the cooled carboxylic acid composition stream 170 for the filter was 403.5 grams (420 grams - 16.5 grams). The weight of the above catalyst removal composition stream from the wet cake was 266.38 grams. The% solids of the wet cake was 94.2%. The wet cake samples were submitted for analysis for IPA analysis.

Experiment 2 (wash ratio 0.5, wash temperature 90 ° C)

700.04 g of the crystallized suspension composition stream 160 was charged into a stainless steel beaker. The suspension was heated until the weight of the suspension was reduced to 420.73 g. The suspension was quenched to 30 ° C using wet ice generating a chilled carboxylic acid composition stream 170. The cooled carboxylic acid composition stream 170 was fed to an experimental scale Pannevis vacuum filter. After feeding the cooled carboxylic acid composition stream 170 to the vacuum filter, 16.5 grams of the cooled carboxylic acid composition stream 170 remained in the stainless steel beaker. The actual mass of the cooled carboxylic acid composition stream 170 for the filter was 405.94 grams (420.73 grams - 14.79 grams). The filter cake was washed with 100.18 g of a stream fed with the 90 ° C 175 acetic acid / water solution wash. The weight of the wet cake post-catalyst removal composition stream 200 was of 232.83 grams. The% solids of the wet cake post catalyst composition stream 200 was 99.2%. The wet cake samples were submitted for analysis for IPA analysis.

Experiment 3 (wash ratio 1.0, wash temperature 90 ° C)

700.39 g of the crystallized suspension composition stream 160 was charged into a stainless steel beaker. The suspension was heated until the weight of the suspension was reduced to 420.25 g. The suspension was quenched to 30 ° C using wet ice generating a chilled carboxylic acid composition stream 170. The cooled carboxylic acid composition stream 170 was fed to an experimental scale Pannevis vacuum filter. After feeding stream 170 to the vacuum filter, 12.69 grams of stream 170 remained in the stainless steel beaker. The actual mass of stream 170 for the filter was 407.56 grams (420.25 grams - 12.69 grams). The filter cake was washed with 200.14 g of the stream fed with the wash of the acetic acid / water solution of 90 ° C 175. The weight of the subsequent catalyst removal stream of the wet cake 200 was 226, 61 g. The% solids of the wet cake post catalyst composition stream 200 was 95.4%. Samples of the post-catalyst removal composition 200 were submitted for analysis for IPA analysis.

Experiment 4 (wash ratio 0.5, wash temperature 10 ° C)

700.3 g of the crystallized suspension composition stream 160 was charged into a stainless steel beaker. The suspension was heated until the weight of the suspension was reduced to 420.3 g. The suspension was rapidly cooled to 30 ° C using wet ice generating a stream of carboxylic acid composition

ES 2 688 198 T3 cooled 170. Stream 170 was fed to an experimental scale Pannevis vacuum filter. After feeding stream 170 to the vacuum filter, 15.29 grams of stream 170 remained in the stainless steel beaker. The actual mass of stream 170 for the filter was 405.01 grams (420.3 grams - 15.29 grams). The filter cake was washed with 100.37 g of the stream fed with the 10 ° C acetic acid / water 175 solution wash. The wet cake post-catalyst removal composition stream 200 weight was 248.84 grams. The% solids of the wet cake post catalyst composition stream 200 was 90.75%. The post-catalyst removal composition samples were submitted for analysis for IPA analysis.

Experiment 5 (wash ratio 1.0, wash temperature 10 ° C)

700.44 g of the crystallized suspension composition stream 160 was charged into a stainless steel beaker. The suspension was heated until the weight of the suspension was reduced to 420.35 g. The suspension was quenched to 30 ° C using wet ice generating a chilled carboxylic acid composition stream 170. The cooled carboxylic acid composition stream 170 was fed to an experimental scale Pannevis vacuum filter. After feeding stream 170 to the vacuum filter, 9.3 grams of stream 170 remained in the stainless steel beaker. The actual mass of stream 170 for the filter was 411.05 grams (420.35 grams - 9.3 grams). The filter cake was washed with 200.06 g of the stream fed with the 10 ° C acetic acid / water 175 solution wash. The weight of the wet cake post-catalyst removal composition stream 200 was 225.06 grams. The% solids of the wet cake post catalyst composition stream 200 was 89.55%. Samples of the post-catalyst removal composition 200 were submitted for analysis for IPA analysis.

Results

Experiment Temp. wash rate IPA wash ratio (ppmp) Top dry (s)

<td> 1</td><td>no washing</td><td>no washing</td><td> 3249</td><td>Na</td>

<td> 2</td><td>90 ° C</td><td> 0,5</td><td> 146</td><td> 5</td>

<td> 3</td><td>90 ° C</td><td> 1,0</td><td> 25</td><td> 10</td>

<td> 4</td><td>10 ° C</td><td> 0,5</td><td> 39</td><td> 9</td>

<td> 5</td><td>10 ° C</td><td> 1,0</td><td> 20</td><td> 17</td>

It is clear that IPA retention varies with wash temperature and wash ratio allowing control of IPA content in post-catalyst removal composition stream 200. Range of IPA content in stream 200 in experiments above ranged from 146 ppm to 20 ppm depending on the amount and temperature of washing. The retention of selected oxidation by-products can be controlled by the temperature, composition, and amount of wash feed stream 175 applied in catalyst removal zone 180. These data illustrate retention of oxidation by-products in a catalyst removal zone using IPA as an example. IPA is considered representative so that other oxidation by-products may show similar retention behavior under specific combinations of wash temperature and wash ratio.

PTA enrichment with isophthalic acid

The aim of this experiment was to demonstrate the enrichment of terephthalic acid.

In Experiment 1, the cooled carboxylic acid composition stream suspension 170 was loaded into an experimental scale Pannevis vacuum filtration apparatus and the resulting subsequent catalyst removal composition 200 was analyzed for IPA content.

In Experiments 2 and 3, the cooled carboxylic acid composition stream suspension 170 was loaded onto an experimental scale Pannevis vacuum filter and the resulting wet cake was washed with wash feed stream 175 and composition stream Post catalyst removal 200 was analyzed for IPA content. Wash feed stream 175 contained 90% acetic acid and 10% water by weight.

In Experiments 4 and 5, the cooled carboxylic acid composition stream suspension 170 was charged

ES 2 688 198 T3 on an experimental scale Pannevis vacuum filter and the resulting wet cake was washed with hot wash feed stream 175. The resulting wet cake from the resulting post catalyst removal composition stream 200 was then washed with enrichment feed stream 220, and the resulting enriched carboxylic acid composition was analyzed for IPA content. Both the catalyst removal zone 180 and the enrichment zone 210 were achieved with the experimental scale Pannevis vacuum filtration apparatus.

In this matter, the enrichment feed stream 220 used in experiments 4 and 5 was prepared. Acetic acid was heated to 80 ° C and sufficient IPA was added until the IPA no longer went into solution.

Experiment 1 (no cake wash, no enrichment wash)

401.67 grams of carboxylic acid stream 170 cooled to 23.9 ° C was fed to catalyst removal zone 180 which was an experimental scale Pannevis vacuum filter. There was no wash feed stream 175. The wet cake weight from stream 200 was 145.55 grams and% solids was 89.4%. A sample of the wet cake was submitted for analysis for IPA analysis.

Experiment 2 (80 ° C cake wash, no enrichment wash)

400.33 grams of the slurry of the cooled carboxylic acid composition stream 170 was fed to

23.9 ° C to catalyst removal zone 180 which was an experimental scale Pannevis vacuum filter. The filter cake was washed with 100.11 grams of wash feed stream 175 of 80.2 ° C. The weight of the resulting postcatalyst removal stream 200 was 139.49 g and the% solids was 99.94%. Samples of the post-catalyst removal composition 200 were submitted for analysis for IPA analysis.

Experiment 3 (80 ° C cake wash, no enrichment wash)

401.17 grams of carboxylic acid composition stream 170 cooled to 24 ° C was fed to catalyst removal zone 180 which was an experimental scale Pannevis vacuum filter. The filter cake was washed with 100.05 grams of wash feed stream 175 of 80.0 ° C. The weight of the resulting postcatalyst removal composition was 124.07 grams and the% solids was 99.95%. A sample of the post-catalyst removal composition 200 was submitted for analysis for IPA analysis.

Experiment 4 (80 ° C cake wash, 80 ° C enrichment wash)

400.45 grams of carboxylic acid composition stream 170 cooled to 24.3 ° C was fed to catalyst removal zone 180 which was an experimental scale Pannevis vacuum filter. The filter cake was washed with 100.11 grams of wash feed stream 175 of 80.1 ° C. The wet cake was then enriched with 100.52 g of enrichment feed stream 220 of 80.2 ° C. The weight of the resulting enriched carboxylic acid composition stream 240 was 131.33 g and the% solids was

99.9%. Samples of the enriched carboxylic acid composition stream 240 were submitted for analysis for IPA analysis.

Experiment 5 (80 ° C cake wash, 80 ° C enrichment wash)

400.55 grams of carboxylic acid composition stream 170 cooled to 24.4 ° C was fed to catalyst removal zone 180 which was an experimental scale Pannevis vacuum filter. The filter cake was washed with 100.28 grams of wash feed stream 175 of 80.2 ° C. The wet cake was then enriched with 100.54 g of the enrichment feed stream 220 of 80.0 ° C. The weight of the resulting enriched carboxylic acid composition stream 240 was 144.54 grams and the% solids was 98.8%. Samples of the enriched carboxylic acid composition stream 240 were submitted for analysis for IPA analysis.

Results

Experiment No. ppm of IPA

IS 2 688 198 T3

2199

1087

804

4676

5535

In experiment 1, the wet cake is not washed, resulting in a concentration of 2199 ppm of IPA. In Runs 2 and 3, the wet cake is washed with stream 175 producing a post catalyst composition 200 with a mean IPA concentration of about 900 ppm. In Experiments 4 and 5, the post catalyst composition 200 is enriched with an enrichment stream 220 to produce an enriched carboxylic composition 240 with an average IPA concentration of about 5000 ppm. It is clear from these data that IPA was enriched in stream 240 at a concentration above that of the subsequent catalyst composition. These data illustrate the enrichment of oxidation by-products in an enrichment zone using IPA as an example. IPA is considered representative of other oxidation by-products where the retention of other oxidation by-products in the catalyst removal zone can be influenced by wash conditions, including wash ratio, wash solvent composition, and wash temperature, as well as the thickness of the cake and the particle size distribution that affects the porosity of the cake.