Process for the preparation of equigranular ion exchange resins for analytical and preparative purposes

(42) Date of commencement of the patent: 15. 7.1989 (45) Date of issue: 12. 2.1990

<td>(56) Documents:</td><td>(73) Patent owner:</td>

<td>US PS3418262</td><td>NITROKEMIA IPARTELEPEK</td>

<td>DERWENT ABSTRACT NO. 71-27450S (WPI), TELESYSTEMS</td><td>H-8184 FUZFÖGYARTELEP (HU).</td>

<td>QUESTEL</td><td>(72) Inventor: ERDELYI ARPADNE CHEM. ING. FUZFÖGYARTELEP (HU). SUMMER LASZLO CHEM. ING. FUZFÖGYARTELEP (HU). LESTYAN JANOS BALATONALMADI (HU). GALAMBOS TAMAS CHEM. ING. VESZPREM (HU). SUMEGI ENDR E ING. FUZFÖGYARTELEP (HU). CZIMER LAJOS ING. FUZFÖGYARTELEP (HU).</td>

(54) PROCESS FOR THE MANUFACTURE OF ION EXCHANGE RESINS OR ADDITIVES USING OVERPRESSURE (57) For the preparation of ion exchange resins by suspension polymerization of vinyl monomers and vinyl group containing compounds in the presence of a pore forming agent and a catalyst. Removal of the pore former and solvents by distillation or extraction followed by Processing of the polymer to an ion exchange resin conveniently by sulfonation, Chloromethylation Hydrolysis -, the polymerization is carried out in a closed system at an overpressure of 0.1 to 15 bar, preferably carried out from 2 to 6 bar.

CD

AT 389 879

Uffl 0078018

No. 389879

The invention relates to a process for the preparation of Inonenaustauscherharzen by suspension polymerization of vinyl monomers and vinyl-containing compounds in the presence of a pore-forming substance and a catalyst removal of the pore-forming agent and the solvent by distillation or extraction and subsequent processing of the polymer to an ion exchange resin conveniently by sulfonation, chloromethylation, Hydrolysis.

The favorable properties of these ion exchange resins over those with gel structure are well known. These include, among others, the favorable kinetic properties, the affinity for the binding of organic substances, a good osmotic stability, excellent chemical and thermal properties. '

You will find in practical fief an ever wider spread. Their production is numerous^J

Patents and publications and can be summarized as follows: Ί

The polymers are obtained by polymerization of vinyl monomers and monomers containing two or more vinyl groups in suspension, using pore-forming substances. The pore-forming substances must be inert from the point of view of polymerization. After the copolymerization, the pore-forming substances z. B. removed by distillation or extraction

The liberated from the pore-forming substances (optionally still containing such) copolymers are sulfonated when cation exchange resins are to be recovered and chloromethylated and then aminated when anion exchange resins are obtained.

In the individual patents differ primarily the pore-forming substances from each other. The relatively numerous methods can be grouped as follows:

a) The pore-forming substances are liquids (aliphatic or cycloaliphatic hydrocarbons, aliphatic or cycloaliphatic alcohols, etc.).

These are characteristic of dissolving the vinyl monomers and vinyl group-containing monomers, but only slightly swelling the polymers. The liquid pore formers are used in such a way that the pore-forming substances and initiators suitable for initiating the radical polymerization are dissolved in the vinyl monomers and in the monomers containing a plurality of vinyl groups and polymerized at the appropriate temperature

The pore-forming substances are removed from the beads predominantly by steam distillation.

The most commonly used pore formers are the following: hexane, n-heptane, i-octane, gasoline derivatives,

Petroleum ether, n-butanol, amyl alcohol, cyclohexanol, etc. Such processes are disclosed in British Pat. Nos. 849,122,942, 388, 1,269,986; in DE-PS 1 045 102; in FR-PS 1 2373 343; in Japanese Patent Publication No. 50-99,641; in U.S. Patent 3,843,568.

b) The pore-forming additives are linear polymers: polystyrene, polyethylene styrene, Polyäthylmetakrylat, Polyäthylakrylsäure, nylon, aliphatic polyester. These polymers are dissolved in the starting vinyl monomers and in the monomers containing a plurality of vinyl groups and, after the copolymerization, are extracted with solvents (toluene, benzene, dichloroethane, etc.) or, in some cases, first saponified and then dissolved out

Such methods have been disclosed in British Patents 1,082,635 and 1115,619; in CS PS 169 290; in the IT-PS 653 359; in U.S. Patent 3,122,512; in the HU-PS 142 661; in FR-PS 1483 946 described.

c) Solvents are also used together with the pore-forming additives. The presence of the solvent in the appropriate ratio has an advantageous (synergistic) effect on the formation of the pore structure. Suitable solvents include aromatic and aliphatic hydrocarbons, chlorinated aliphatic and aromatic hydrocarbons (benzene, toluene, xylene, chlorobenzene, dichloroethane),

Ketones, esters are used.

This mode of formation of the macroporous structure is described in British Patent Nos. 1,269,986 and 1,483,578; in FR-PS 2 044 630; in JP-PS 53-82 867; described in DE-PS 2 121448.

The adsorbent resins are special ion exchangers which differ from the previously described macroporous ion exchange resins in their preparation or in their composition only insofar as they generally do not contain active groups, and their specific surface area and pore volume are substantially greater than those of the ion exchange resins. In the production of the macroporous ion exchange matrixes and the adsorbent copolymers, inert substances are often used as pore formers and solvents whose boiling points are close to the polymerization temperature, or their vapor pressures are relatively high at the polymerization temperature. The preparation of the ion exchange matrixes takes place practically in an aqueous medium, by polymerization in suspension. Due to the presence of an organic and an aqueous phase, an immiscible liquid system is formed. For such, it is characteristic that the system boils at a lower temperature than any of the components. This is accompanied by the disadvantage that the inert material or a part of which is easily released from the suspended monomer mixture and subsequently, as the polymerization proceeds, from the polymerizing grains&gt;

and gives a product with halbmakroporöser or gel-like structure. There may also be incidence that due to the relatively high tension, the pore radii will be greater than optimal. The polymerization temperature is thus determined by the inert substances for the abovementioned reasons, and thus the quality of the copolymer as well as the temperature profile which is optimal from the economic point of view of production can usually not be realized.

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The pore-forming substances and solvents must be removed after the copolymerization by distillation or extraction from the polymer. Most economically, those solvents and / or pore-forming substances can be recovered, which can be removed from the beads by distillation, advantageously by steam distillation. Difficulties arise during the polymerization, especially in these cases, because the boiling point of the aqueous phase / organic phase system is at a relatively low temperature, the vaporization rate of the pore-forming substances is high even at this relatively low temperature, and more of the beads pore-forming substance escapes as desirable. When using a reflux condenser on the apparatus can also not be ensured that the pore-forming substances are only released from those beads from which they have leaked, or that they will ever return to the grains in polymerization.

In the preparation of suitable copolymers for ion exchangers and adsorbents having a corresponding volume and mass capacity and with a corresponding porosity, it is necessary to keep the ratio of the pore-forming substances and the monomers within narrow limits. If this ratio undergoes a relatively small change during polymerization due to change in any manufacturing factor in the beads, the desired porosity can no longer be achieved.

One must also reckon with the following disadvantages:

Since the polymerization must be conducted at a relatively low temperature, unreacted monomer remains. When distilling off the pore-forming substances, a post-reaction takes place as a result of the higher temperature, which deteriorates the porosity. Japanese Patent Publication No. 53-82,867 seeks to eliminate this drawback by employing an inhibitor during removal of the pore-forming agent.

During the polymerization, care must be taken that the temperature difference between the polymerization temperature and the reactor wall temperature should be relatively low, since in the opposite case the suspended monomer and / or polymer grains reaching the reactor wall are heated above the desired temperature and thus the can escape pore-forming agent. In the operating reactors, the heating rate is necessarily low because of the allowable small temperature difference, and thus the achievement of the polymerization temperature takes a long time.

Due to the relatively low polymerization temperature, the polymerization times are relatively longer. For example, in the application of i-octane, the polymerization must be carried out atmospherically below 75 ° C, therefore, the polymerization time is 8 to 12 hours.

The object of the invention is to eliminate the disadvantages arising from the known processes in the production of ion exchange resins and adsorbents.

This object is achieved in that the polymerization in a closed system at an overpressure of 0.1 to 15 bar, preferably from 2 to 6 bar, is performed.

The pressure can be brought about in a closed polymerization system also during the heating by the partial pressures of the substances, but expediently with an inert gas - advantageously N₂-Gas - an overpressure applied where the boiling point of the system certainly remains below the applied polymerization temperature.

During the practical realization of the method, the reactor is rinsed after the measurement of the necessary substances with nitrogen gas, sealed and placed under the necessary nitrogen pressure. When using i-octane as a pore former 2 bar, in the case of pentagemic 6 bar Überdurck applied before starting the reactor heating.

The polymerization is carried out at 50-120 ° C, advantageously at 70-97 ° C. To form a corresponding pore structure, the application at the beginning of a polymerization time of 3-5 hours at 70-90 ° C and then to reduce the residual monomer content of 2 hours at 90-97 ° C is convenient, practically using a double catalyst. In this case, one of the catalysts exerts its effect at the lower, the other at the temperature of the postpolymerization.

The pore-forming substances are removed in a known manner. For the selection of these substances the possibilities already described are given:

- Pore-forming agents (liquids) to be removed by distillation or steam distillation;

- common use of the above pore formers and synergistic solvents;

Use as a pore former of a polymer soluble in the vinyl monomer and in the monomer containing several vinyl groups with synergistically acting solvents.

The substances which can be used according to the process are:

- Vinyl monomer compounds.

Ethylene-type, containing an unsaturated double bond or vinyl group-containing monomers, for example, aliphatic group or halogen element-containing vinyl monomer derivatives (styrene, vinylchlorobenzene, vinylnaphthalene, vinylanisole, ar-methylstyrene, Ar-dimethylstyrene, Ar-ethylvinylbenzene, arylstyrene-ethylvinylbenzene), aliphatic vinyl monomers and monovinylidenecarboxylic acids and their derivatives (methyl acrylate, ethyl acrylate , Ethylmethacrylic acid, acrylonitrile, etc.) The most commonly used compound is the styrenic monomer.

Crosslinking compounds: compounds containing two or more unsaturated bonds (polyenes), aromatic compounds containing a plurality of vinyl groups, and aliphatic carboxylic acid esters having

-3Nr. 389879 unsaturated alcohols (eg divinylbenzene, divinylethylbenzene, divinylxylenes, divinyltoluene, divinylnaphthalene, 2,4,6-trivinylethylbenzene, ethylene glycol diacrylate, ethylene glycol dimethyl acrylate, diallyl adipate, diallyl maleate, diallyl fumarate, butadiene, isoprene, cyclopentadiene, diallyl phthalate, diallyl isophthalate, triallyl isocyanurate, diallyl succinate, Diallyl carbonate, diallyl azelaine, diallyl tartrate, diallyl oxalate, triallyl citrate, N, N'-methylene diacrylamide).

- Poland-forming substances:

Aliphatic and cycloaliphatic hydrocarbons (for example butane, pentane, hexane, haptan, iOctane, nonane, decane, cyclopentane, cyclohexane), aliphatic or cycloaliphatic alcohols (for example propanol, butanol, amyl alcohol, cyclohexanol), gasoline and petroleum fractions and paraffin oil.

Polymers soluble in vinyl monomer and monomer containing a plurality of vinyl groups (for example, polystyrene, polymethylstyrene, polyethylstyrene, polyvinylacetate, polyisobutane, polymethylacrylate, polymethyl methacrylate, polyethyl methacrylate, polybutyl methacrylate, polymethacrylic acid, polyethylacrylic acid, polybutylmethacrylic acid, polyvinylxylene, styrene / butadiene copolymer).

In addition to the above, the pore-forming agents described in IT-PS 653 359, in BE-PS 856 502, in GB-PS 1 483 587 and in JP-PS 75-123 088 can also be used.

Solvent:

Aromatic and aliphatic hydrocarbons, chlorinated aromatic and aliphatic hydrocarbons (benzene, toluene, xylene, chlorobenzene, carbon tetrachloride, tetrachloroethane, dichloroethane, ethylbenzene, etc.), ketones (methyl isobutyl ketone), esters (n-butyl acetate, hexyl acetate).

- Stabilizers:

The most commonly used stabilizers: polyvinyl alcohol, sodium polyvinyl methacrylate, sodium polyacrylate, carboxymethyl cellulose, starch, polyethylene glycol, dextrin, cellulose, polysaccharides, polyvinylpyrrolidone).

- Catalysts:

In the radical polymerization suitable as initiators compounds used, such as dibenzoyl peroxide, t-butyl peroxide, cumene peroxide, t-butyl hydroperoxide, acetyl peroxide, t-butyl perbenzoate Methyläthylketonperoxyd, azo-bis-isobutyrodinitrile.

The amounts or proportions of the individual components generally vary at the following intervals based on the total mass of the vinyl monomers and the monomers containing a plurality of vinyl groups:

Vinyl monomers: 40-99% (preferably 75-95% by mass)

- several vinyl group-containing compounds: 1-60 mass% (preferably 5-25 mass%)

Pore ​​formers: depending on the pore former used and on the pore volume and specific surface area to be achieved 5-150 mass%

Solvent: depending on the type of solvent and the pore structure to be filled 10-300% by mass (preferably 15-130% by mass)

Catalysts: generally 1-3 mass%

Stabilizers: 0.05-5 mass% based on the polymerization medium.

The following examples serve to illustrate the process:

example 1

The medium of the suspension polymerization is prepared by immersing in 8000 cm⁵ Water as stabilizer Boost 160 g of starch. In the thus prepared, recooled solution at a stirring grain intensity corresponding to the trainee particle size of 36-60 revolutions per minute of 210 g of styrene, 65.6 g 61% by mass divinylbenzene and 165.4 g of i-octane, 5.5 g of dibenzoyl peroxide, 2.7 g of t-butyl perbenzoate existing mixture added.

The reactor is purged with nitrogen gas, sealed and pressurized to 2 bar with nitrogen gas. Polymerization is carried out at 70-90 ° C for 4 hours and at 90-97 ° C for 2 hours. At the end of the reaction, the temperature in the reactor is 97 ° C, the pressure 3.95 bar. The i-octane is distilled off with steam (the recovered amount is 146 g). The polymer is filtered, washed and dried. This gives 262 g opaque macroporous polymer.

50 g of the polymer prepared as above are swollen in dichloroethane and then added to 300 g of 98% sulfuric acid measured in a sulphonating flask and sulphonated at 80-105 ° C. for hours. After sulphonation, the mixture is diluted with water, converted with 4% by mass. acid solution in the Na form and filtered. The characteristic numbers of the strongly acidic 220 ml cation exchange resin are listed in Table 1

Example 2

The procedure is as in Example 1, with the difference that instead of i-octane, pentane is now metered in and nitrogen gas is used to set an overpressure of 7 bar.

The characteristics of the product obtained are listed in Table 1.

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Example 3

The medium of the suspension polymerization is prepared by immersing in 8000 cm³ Water as a stabilizer 160 g of starch are boiled. To the recooled polymerization medium is added the mixture of 254 g of styrene, 26 g of 64% divinylbenzene and 168 g of i-octane, 5.6 g of dibenzoil peroxide, 2.8 g of t-butyl perbenzoate

The polymerization is carried out as in Example 1, then 150 g of the polymer prepared as previously measured in a stirred flask, 100 g of zinc chloride and 440 g Monochloräthyläther added. It is chloromethylated with constant stirring for 5 hours. The excess monochloroethyl ether is decomposed and the product is washed neutral. The chloromethylated polymer is aminated with 740 ml of 40% trimethylamine at 35-40 ° C for 5 hours. The amount of the strongly basic anion exchange resin obtained is 1400 cm³ and its key figures are shown in Table 1.

Example 4

The procedure is as in Example 3, with the difference that one measures 190 g of i-octane.

The properties of the product obtained are shown in Table 1.

Table 1

property

Example no.

2 3 4

<td>0 Volume capacity (mVal / cm)</td><td>1.65</td><td>1.68</td><td>1.2</td><td>1.0</td>

<td>Mass capacity (mVal / g)</td><td>4.65</td><td>4.57</td><td>4.0</td><td>3.9</td>

<td>Volume change Na⁺/H⁺(%)</td><td>4.0</td><td>3.7</td><td>12.0</td><td>11.5</td>

<td>Pore ​​volume (ml / g)</td><td>0.26</td><td>0.35</td><td>0,025</td><td>0.031</td>

The pore volume was determined with a POROSIMETER Carlo-Erba according to the mercury penetration method between 1-1000 bar.

Example 5

The procedure is as in Example 1 with the difference that the catalyst 194 g of styrene, 81 g of 61% divinylbenzene, 192 g of n-heptane einmißt and adjusts an excess pressure of 6 bar with nitrogen gas. The pore volume of the obtained polymer is 0.4184 ml / g, its specific surface area is 90.6 m / g.

The specific surface area was measured with a BETOGRAPH from Atlas Mat. With this apparatus, at the temperature of the liquid nitrogen (77.4 K, -195.8 ° C), the adsorption isotherm of the argon gas can be registered in the range of validity of the BET equation and the specific surface area calculated therefrom.

After the polymerization, a strongly acidic cation exchanger is prepared as in Example 1.

Example 6

Production of an adsorbent resin

The polymerization is carried out as in Example 1, with the difference that 158 ​​g of styrene, 117 g of 61% divinylbenzene, 275 g of i-octane and 56 g of toluene are metered into the catalyst.

The pore volume of the polymer produced is 0.6856 ml / g, its specific surface 286 m / g.

Example!

Production of an adsorbent resin

The polymerization is carried out as in Example 1, with the difference that the catalyst 120 g

Styrene, 160 g of 61% divinylbenzene, 28 g of polystyrene of molecular weight 5.2.10³ and 280 g of toluene are metered.

After the copolymerization, the polystyrene is extracted with toluene. The pore volume of the resulting macroporous copolymer is 0.6528 ml / g, its specific surface area (according to the BET method) 302 m / g.

Example 8

In 8000 cm³ Water is boiled 160 g of starch. In the thus prepared, recooled polymerization medium is at a desired grain size corresponding stirring intensity of 36-50 revolutions / minute as a monomer, a mixture consisting of 18 g of 61% Divinylbenzol, 14 g

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Acrylonitrile, 28 g Methyläkrylat and then added in 170 g of i-octane dissolved mixture of 5.5 g of dibenzoyl peroxide and 2.7 g of t-butyl perbenzoate.

The apparatus is purged with nitrogen gas and then placed under a positive pressure of 2.5 bar. It is polymerized at 75-90 ° C for 5 hours and then at 90-97 ° C for 2 hours. Thereafter, the i-octane is distilled off with steam, the resulting opaque beads are washed, dried, their amount is 268 g. The recovered i-octane amount is 142 g. Of the polymer thus prepared 50 g are added to a predetermined amount of 20 mass% potassium hydroxide and hydrolyzed at 75-100 ° C for 6-8 hours, diluted with water, with 6.8 mass% hydrochloric acid in the H⁺Transferred form and then filtered.

This gives 132 ml of weakly acid cation exchange resin. The pore volume of the copolymer is 0.09 ml / g, its volume capacity 9.3 meq / g.

Example 9

Production of a Selective Ion Exchange Resin

100 g of the chloromethylated and neutral-washed polymer according to Example 3, 100 g of thiourea and 1000 ml of water are stirred at 82-86 ° C for 3 hours.

The nitrogen content of the product obtained is 11.5 mass%. The ion exchange resin thus prepared is suitable for forming Au, Ag, Pt, Pd and Hg

Example 10

The medium for the suspension polymerization is prepared by boiling 160 g of starch as stabilizer in 8500 ml of water. Into this recooled polymerization medium are added 213 g of styrene, 62 g of 61% Divinylbenzol and dissolved in 206 g of i-octane 5.5 g of dibenzoil peroxide

The apparatus is purged with nitrogen gas and sealed. Next proceed according to Example 1 with the difference that no nitrogen pressure is applied. The polymerization is carried out between 70-95 ° C. During the polymerization, the pressure increases to 1.35 bar.

The resulting polymer weighs 250 g which, as sulfonated as in Example 1, gives a strongly acidic macroporous ion exchange resin

- Mass capacity: 4.3 mVal / g

- Volume change Na⁺/H⁺: 3.2%

Pore ​​volume of the polymer: 0.18 ml / g.

Example 11

The procedure is as in Example 1, with the difference that the polymerization is carried out without pressure. The product obtained has a gel structure, has a pore volume of 0.0154 ml / g and a BET not measurable specific surface area.

Example 12

The polymerization is carried out according to Example 1 with the difference that 140 g of styrene, 135 g of 61% divinylbenzene, 320 g of i-octane and 82 g of toluene are reacted.

The pore volume of the polymer produced is 1.5169 ml / g, its specific surface 412 m²/G.