Metal phthalocyanine catalyst

(54) Title: Metal phthalocyamine catalyst, and its use (56) Publications cited: US 3,074,958

7701773-9 ^r The invention relates to a new catalyst for use in the treatment of hydrocarbon distillates and in particular to the oxidative treatment of acidic hydrocarbon distillates by oxidation of the mercaptans in the distillate to disulfides.

Oxidative treatment of hydrocarbons in solid beds is a well-established range of techniques. A representative solid bed oxidative process is described in U.S. Patent No. 2,988,500 to which reference is made herein. In that patent, an acidic petroleum distillate is contacted with a solid bed of a metal phthalocyanine catalyst on a charcoal carrier in the presence of oxygen and an alkaline reagent. The advantages of solid bed treatment are that the operator has great opportunities to control the oxidation process and can be quite sure that the entire hydrocarbon material, which has passed through the fixed bed, is actually undergoing treatment.

Liquid-liquid oxidation is also a well-known technique in refining. According to this method, a metal chelate is dispersed or dissolved in an alkaline medium. The alkaline medium can be used to extract mercaptans from a hydrocarbon material during regeneration of the alkaline medium via oxidation of mercaptans to disulfides in a separate vessel. Alternatively, the hydrocarbon material, the alkaline

7701773-9 ^rthe catalyst medium and an oxidizing agent are contacted with each other in a single vessel. U.S. Patent No. 2,853,432, to which reference is made herein, discloses information on catalysts and alkaline media which may be used. Said patent also teaches that it is desirable to use a sulfonated derivative of a metal phthalocyanine to increase the solubility of the phthalocyanine catalyst in the alkaline medium.

A common feature for oxidation processes in both solid bed and liquid-liquid phase is the use of a metal phthalocyanine catalyst. Many methods for preparing metal phthalocyanine are known. One such method of preparation consists of contacting metal hydroxide with quinoline in an inert organic solvent and then adding a solution containing a phthalonitrile to obtain the desired phthalocyanine compound. The metal phthalocyanines can be halogenated by various methods, as described in U.S. Pat. Nos. 3,393,200 and 3,252,992. nitrogen donor, a metal donor and ammonium chloride to improve the yield of the metal phthalocyanine compound.

Due to the interest in making soluble phthalocyanines soluble, especially for use in liquid-liquid phase oxidation processes, much work has been devoted to preparing sulfonated derivatives of the metal phthalocyanines. Perhaps even greater work has been done on metal phthalocyanines because of the usefulness of these compounds as dye and pigment.

Only two basic methods for preparing sulfonated derivatives of metal phthalocyanines are known. Perhaps the oldest method is · sulfonation in oleum. An example of a sulfonation method is disclosed in British Patent Specification 503,029 which describes the preparation of copper phthalocyanines with subsequent reaction of the phthalocyanines with sulfuric acid to produce a product called a sulfate. The preparation of 4-sulfonated copper phthalocyanines is described in Chem. Abstracts, Volume 71, 1031530 (1969), by which method a tetrasulfonate is prepared by first preparing the phthalocyanine and then effecting sulfonation in oleum or sulfuric acid.

In the publication J. Chem. Soc. (A), 90 (1963) describes the preparation of a cobalt phthalocyanine tetrasulfonate from cobalt phthalocyanine

7701773-9 ^rby sulfonation in sulfuric acid and oleum. In the publication ZH. Organioheskoi Khim., 9,1822-1830 (1973) discloses the preparation of phthalocyanines by reaction of metal powder with phthalonitrile. The phthalocyanines were prepared using nitrobenzene as a solvent. This material was sulfonated using oleum.

The second basic method of preparation for sulfonated derivatives of phthalocyanine consists in the preparation of a phthalocyanine with reactants which already contain a sulfuric group. In these methods, each phthalocyanine produced automatically constitutes a sulfonated phthalocyanine. In principle, the catalyst proposed according to the present invention is an improved product of the latter, i.e. reactants containing sulfur groups are used to prepare a sulfonated phthalocyanine.

Before discussing the present invention in more detail, the state of the art will be briefly discussed below. In the publication Nippon Kagoku Zasshi 79, 396-9 (1958) various methods for the preparation of phthalocyanine tetrasulfonates are disclosed. The tetrasulfonates are prepared in principle using tri-ammonium U-sulfophthalate. The reaction takes place at 240 ° C. Various modifications of this method have been proposed, such as the method described in Inorg. Chem. 4, 469-71 (1965), Ibid, 472-5, according to which nitrobenzene was used as a solvent. Another variant of the method described above is disclosed in Kinet Katal 81325-30 (1967), which describes a reaction in melt or dry reaction which takes place at 200-210 ° C for 6 hours. It is stated that said catalyst can convert cysteine ​​to cystine. This is an example of conversion of a mercaptan to a disulfide, although it is carried out in a biological system comprising an amino acid.

Another closely related method for the preparation of sulfonated phthalocyanines is described by Przywarska-Boniecka in Rocz. Chem. 41, 170310 (1967), which describes a similar method as the one mentioned above but states that the maximum reaction temperature should be at 240 ° C. The metal used was rhenium. The oxidation of mercaptans was never studied.

In the main purpose of finding an improved catalyst for the conversion of mercaptans, studies have been conducted with the intention of obtaining not only a better mercaptan conversion process but, if possible, a better method of producing the catalyst for use in the process. The existing methods of catalyst preparation have never been entirely satisfactory, since the preparation of the catalyst

7701773-9 in oleum or sulfuric acid is very tangled and involves the use of dangerous reagents (sulfuric acid) and the reaction product must be purified before it can be used. In addition, the catalyst activity of sulfonated derivatives of phthalocyanine catalysts prepared by sulfonation in oleum or sulfuric acid was not as high as desired. The second general method of preparing tetrasulfonate, which may be called the Fukada method with a general term, brought about a considerable improvement over direct sulfonation methods, in that it was possible to avoid using and having to take advantage of sulfuric acid and certain purification steps could be eliminated. Unfortunately, the catalysts prepared by Fukada's method were not as active for conversion of mercaptans as desired.

The object of the invention was therefore to try to develop a method for preparing phthalocyanine tetra sulfonates, in which the difficult methods of preparation associated with direct sulfonation could be avoided and which could also provide a catalyst with greater activity than those obtained by preparation by direct sulphonation or according to Fukada's method.

The invention thus relates to a catalyst consisting of a metal phthalocyanine composition comprising the reaction product of a mixture of a 4-sulfophthalic acid compound, a metal salt, an ammonium donor compound and water, characterized in that said mixture is reacted at 255-325 ° C for a time between 1/2 hour and 10 hours.

In another embodiment, the invention relates to a process for preparing a catalyst which consists in reacting a mixture of a 4-sulfophthalic acid compound, a metal salt, an ammonium donor compound and water at a time between 1/2 hour and 10 hours.

The invention also relates to the use of the catalyst for the oxidation of a sulfur-containing compound with oxygen or oxygen-containing gas in the presence of an alkaline medium.

The invention provides an improved method of removing or converting sulfur-containing compounds into various hydrocarbon distillates. One of the worst sulfur-containing compounds is mercaptans. The type of mercaptans varies depending on the type of starting material.

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In natural gas, methyl mercaptan or ethyl mercaptan may be present. In heavier crude oils or naphtha there may be tertiary dodecyl mercaptans or aromatic mercaptans such as thiophenol. By utilizing the present invention, a better method is provided for removing and converting various mercaptan compounds.

Another aggressive sulfur-containing compound is hydrogen sulfide. Sulfur hydrogen can be formed during refining of crude oil, chemical processes or in steel production. By utilizing the present invention, it is possible to more effectively convert sulfur hydrogen to elemental sulfur by oxidation. The invention also provides a more convenient method of preparing metal phthalocyanine catalyst to obtain a more desirable catalyst product.

The utility of the new catalyst consists in its use as a catalyst in the oxidation of sulfur compounds, e.g. for the conversion of acid-smelling mercaptan compounds into disulfide compounds or the conversion of hazardous sulfur hydrogen gas to elemental sulfur. The catalyst can also be used in various electrochemical reactions, biochemical reactions, hydroformulation reactions, reforming, alkylation, transalkylation, Diels-Age reactions, cycloalkylation, dehydration, decyclodehydration, oxidation of various organic compounds to ketones and carboxylic acids, reduction of inorganic and organic solutions organic solution etc.

When the catalyst of the invention is used for the conversion of mercaptans, the treatment conditions comprise a temperature of 0-500 ° C, a pressure of 1-100 ata and preferably so adapted that liquid phase is maintained. Oxidizing agents which can be used include pure oxygen or oxygen mixed with other gas, such as oxygen-nitrogen mixtures (air), etc.

The sulfur compounds may be either in pure form or involved in a petroleum distillate, an aqueous feed stream or an alkaline aqueous feed stream. Mercaptans in hydrocarbon materials vary from mercaptans having between 1 and 19 carbon atoms. Other mercaptan compounds, which may also be present, include aromatic mercaptans, such as thiophenol or branched, aliphatic, difficult-to-treat mercaptans, such as tertiary dodecyl mercaptans. The sulfur-containing compounds include hydrogen sulfide dissolved in an aqueous solution, e.g. Sulfur hydrogen dissolved in sodium or calcium hydroxide or in water.

According to a preferred embodiment, the sulfur compound is converted

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Γ in an alkaline medium of pH 8-14, preferably pH 11-14. The catalyst may be dispersed on a solid support, e.g. charcoal or other carrier, or dispersed in an alkaline liquid medium.

The alkaline medium can be any conventional alkaline medium used in such treatment processes. Sodium hydroxide solutions are usually used because they are cheap and readily available.

Essential in connection with the invention are the conditions in the reaction zone in which the catalyst precursor materials are present at a temperature of 255-325 ° C. The pressure is preferably high enough to maintain liquid phase. The reaction time can vary from 1/2 hour to 10 hours.

It is also within the scope of the invention to raise the temperature successively to the specified temperature between 255 and 325 ° C. Experiments have shown that this is not a preferred method when maximizing mercaptan oxidation activity is desired. However, it is possible to utilize one or more preliminary heating steps at lower temperatures, e.g. 120-150 ° C for 1 / 2-2 hours followed by a temperature between 150 and 250 ° C for 1 / 2-2 hours with subsequent treatment in the temperature range proposed by the invention. It may be advisable to slowly approach the specified temperature range of 255-325 ° C to allow part of the gases formed by phase change or chemical reaction to pass away. It is not entirely clear what is going on at temperatures above 255 ° C in relation to the lower temperatures used in the prior art, but another product is obtained.

Surprisingly, no studies have been done at these higher temperatures regarding sulfonated derivatives of phthalocyanines. There is a tendency for these materials to self-calcine at higher temperatures. This is why earlier temperatures above 240 ° C have been avoided. Working at temperatures lower than 255 ° C does not provide enough of the desired product to show an improvement in catalytic activity for the oxidation of mercaptans. The product obtained by operating at low temperature according to prior art would be very closely related to chemical properties with previously known catalysts, e.g. the catalysts described by Fukada and Kundo. Working at temperatures above 325 ° C is not possible as the material would almost completely self-calcine. Working at temperatures between 310 and 325 ° C is only possible if accurate

7701773-9 ^rprecautions are taken to exclude oxygen in the mixture or if an excess of water and overpressure is used.

The reaction can be accelerated with some activator, e.g. boric acid, ammonium chromate, chromic oxide, selenic acid, ammonium chloride, iron (III) chloride, potassium vanadate, vanadic acid, lead monoxide, lead dioxide, zinc oxide, arsenic acid, antimony oxide, molybdenum oxide, phosphomolybdic acid, molybdenum acid,

The reactants used include 4-sulfophthalic acid and derivatives thereof, such as acid salts. The 4-sulfophthalate salts may also exhibit a cation of such elements as lithium, potassium, rubidium, cesium, barium, strontium, calcium, magnesium, beryllium, titanium, scandium, zirconium, manganese, rhenium, and examples of such salts are sodium 4-sulfophthalate, disodium-4-sulfophthalate, trisodium-4-sulfophthalate, lithium-4-sulfophthalate, dilitium-4-sulfophthalate, beryllium-4-sulfophthalate, magnesium-4-sulfophthalate, calcium 4-sulfophthalate, potassium 4-sulfophthalate, dicalcium 4-sulfophthalate, scandium-4-sulfophthalate, titanium-4-sulfophthalate, manganese-4-sulfophthalate, etc.

The metal salt may comprise any Group VIII metal salt of the periodic system, such as cobalt sulfate, cobalt acetate, cobalt chloride, cobalt dichloride, cobalt sulfate, cobalt sulfate heptahydrate, cobalt ammonium chloride, cobalt ammonium sulfate, cobalt bromide, cobalt iodide, cobalt iodide, cobalt iodide, cobalt iodide, cobalt iodide, cobalt iodide, cobalt iodide. , palladium, platinum, osmium and iridium. In addition to the Group VIII metals, it is likely that other metal salts such as vanadium, chromium, molybdenum, tungsten, zirconium, scandium, titanium, manganese and zinc can also be used. The metal used in the metal phthalocyanine catalyst may also be derived from a metal salt obtained from the metal powder during the course of the reaction.

The ammonium donate compound decomposes to form ammonia or an ammonium group (ΝΗ⁺). Suitable suitable ammonium donor compounds include urea, alumammonium chromium, alumammonium iron, alumunium, aluminium (potassium), alumonium manganese, alumina, alumina, ammonium nitrate, ammonium benzoate, ammonia benzoate, ammonium benzoate, ammonium benzoate, ammonium borate, ammonium borate, ammonium borate,

The metal phthalocyanine compound prepared according to the invention comprises a sulfonated iron phthalocyanine, cobalt phthalocyanine, nickel phthalocyanine, palladium phthalocyanine, rhodium phthalocyanine, ruthenium phthalocyanine, osmium phthalocyanine, iridium phthalocyanine, platinum naphthalocyanine, platinum

The 4-sulfophthalic acid salts listed above, metal salts, sulfur-containing compounds, alkali reaction media and ammonium donor compounds are only representative examples of materials which can be used in connection with the invention and are not necessarily limited thereto.

The catalyst is prepared either batchwise or continuously. In continuous preparation, the reactants can be contacted with each other in a plug flow reactor, a reactor with a continuous stirring tank or combinations thereof, at the appropriate temperature and pressure for a sufficient period of time to form the desired catalyst material. As described in the following examples, batch preparation can also be applied.

The treatment of the sulfur-containing compounds can be carried out in any suitable manner and may include batch or continuous processes. A continuous process of the type exemplary is described in US Patent 2,988,500, i.e. a solid bed treatment process is an acceptable method of treating mebcaptan-containing distillates, but the catalyst of the invention is relatively soluble in alkaline media. This solubility can be better utilized in a liquid-liquid phase oxidation process, since it allows almost complete use of the catalyst. Details of the use of a liquid phase catalyst are disclosed in U.S. Pat. Nos. 2,853,432 and 2,882,224, which are referred to herein »

Example I

In this example, a catalyst prepared by Fukada's method was used. In a reaction vessel, 20.0 g (0.067 mole) of triammonium 4-sulfophthalate, 30.0 g (0.5 mole) of urea, 5.31 g (0.0189 mole) of cobalt sulfate heptahydrate, 0.3 g of ammonium molybdate and 30.0 g were mixed. g of water. The mixture was incrementally heated from 120 to 220 ° C for 6 hours at atmospheric pressure. The reaction mass was then allowed to cool and ground to a powdery material, called catalyst A.

The mercaptan oxidation activity of this catalyst was tested for conversion of thiophenol to its corresponding disulfide in the presence of oxygen. 1.28 g of thiophenol under 1 atmosphere (3 "pressure at 22 ° C was used in this test. The time required to convert 1.28 g of thiophenol to the corresponding disulfide was 37.5 minutes" Example II

This example shows the preparation of a catalyst with

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application of a modification of Fukada's method as taught by Kundo. An example of this method, a dry melt method, consists of mixing 302 g of triammonium 4-sulfophthalate, 976 g of urea, 142 g of cobalt sulfate heptahydrate and 0.5 g of ammonium molybdate. Of this mixture, 450 g of a 2 liter container was charged, which was then heated at 220-235 ° C for 4.75 hours. The reaction product was allowed to cool, withdrawn from the reactor and pulverized prior to examination of its activity. This catalyst was called Catalyst B.

The mercaptan oxidation activity of this catalyst was tested for conversion of thiophenol to the corresponding disulfide in the presence of oxygen. The time taken to convert 1.28 g of thiophenol to the corresponding disulfide was 29 minutes.

Example III

In this example, a catalyst was prepared by mixing in a beaker 20 g (0.67 mole) of triammonium 4-sulfophthalate, 30.0 g (0.5 mole) of urea, 5.31 g (0.0189 mole) of cobalt sulfate heptahydrate, 3.0 g ammonium molybdate and 30.0 g water. The reaction mixture was heated on a sand bath at 160-170 ° C for 2 hours and heated at a temperature of 210-220 ° C for 2 hours. The reactants were then heated to 260-270 ° C for 2 hours, after which the reaction mixture was allowed to cool. The reaction mass had a bi-black color and was ground to a powdery material. This was called catalyst C.

The time, which took place before? to convert thiophenol to disulfide for this catalyst was 25 minutes. To confirm the improved results, the experiment was repeated with a similar catalyst. The time for the conversion of thiophenol was then 22 minutes. Example IV

This example shows a preferred method of preparing the catalyst of the invention. 20 g of triammonium 4-sulfophthalate, 5.31 g of cobalt sulfate heptahydrate, 30 g of urea, 0.3 g of ammonium molybdate and 30 g of water were stirred and then heated to about 265 ° C.

4.5 hours. The catalyst thus obtained, catalyst D, exhibited a thiophenol conversion time as above of 20 minutes.

Example V

This example shows the best known method of preparing a catalyst according to the invention. The same reagent was used as in Example IV and stirred and heated to 270 ° C for 5 hours. This catalyst, catalyst E, had a thiophenol conversion time as above of 15 minutes.

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Thus, in the experiments to be judged, a very active catalyst is obtained without the hassle and risks of direct sulfonation in the oleum and with mercaptan conversion activities, which clearly transcend the corresponding activity of similar catalysts prepared according to the prior art. This higher activity is readily recognized by considering that almost twice as much (29/15) of the known catalyst (catalyst B) would be required in a commercial oxidation process to achieve the same mercaptan conversion rate as with the catalyst prepared according to the invention (catalyst E).

Example VI

In this example, 226 kg of cobalt phthalocyanine tetrasulfonate catalyst was prepared. 0.1 kg of molybdenoic acid and 73 kg of cobalt sulfate are dissolved in 465 kg of a 50% by weight solution of 4-sulfophthalic acid. 315 kg of carbamide was then added and dissolved. The solution was placed in bottoms and then transferred to an oven. The reaction temperature used was as follows: (a) 177 ° C for 2 hours, (b) 218 ​​° C for 2 hours and (c) 260 ° C for 4 hours. The oven was allowed to cool and the bottoms were removed for unloading. The product was ground and packaged. The catalyst, catalyst F, exhibited a thiophenol conversion time as above of 15 minutes »

The method described above applies to commercial cobalt phthalocyanine tetra sulfonate catalyst production plants. This method is in line with the idea of ​​the present invention since the last heating step, step (c), relates to the new of the invention according to claim 1.

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