SU759533A1 - Method of preparing anion-exchange resins - Google Patents

Description

The invention relates to the production of ion exchange sorbents, in particular to the production of anion exchange resin of isoporous structure. . five

Known methods for producing crosslinked polystyrene by reacting it with benzene dichloro derivatives and. diphenyl in dichloroethane or with a mixture of sulfuryl chloride and methyl al [2] ·

Anion-exchange functional groups are introduced into the obtained three-dimensional polymers by the usual methods of polymerase. Similar transformations. Thus, the process of obtaining isoporous ion exchangers is more time-consuming than the production of standard ion exchangers. In the process of stitching, extraneous compounds are introduced, which alter the properties of sorbents. That PE is a disadvantage of the known methods.

There is also known a method of producing isoporous aionites by which the stitching of polystyrene is combined with the 25 chloromethylation process of monochloromethyl ether in the presence of Friedel-Crafts catalysts. Stitching polystyrene is carried out by side reaction _vn condensation chloro-

2

polystyrene methyl groups and unsubstituted aromatic nuclei [3].

According to known methods, it is possible to obtain only block-type isoporous sorbents, since the suturing of polystyrene is preceded by its dissolution (as well as styrene copolymers with divinylbeneol containing up to 0.2% divinylbenzene) in the reagents used. Ionites with a regular spherical shape of granules, obtained on the basis of styrene copolymers with 0.5-2.0% divinylbenzene are not uniformly porous, since they contain several types of cross-linking. In them, as in the standard gel ionites of a heteroporous structure, there are areas of increased density that impede sorption, which are formed during the polymerization of divinyl compounds.

Technologically, the introduction of crosslinking into copolymers with a low content of divinylbeneol and the production of durable industrial ion exchangers is an extremely difficult process due to the high swelling capacity of the copolymers under the conditions of the stitching reaction (see table).

Obtaining anion exchange resin according to a known method is performed in 3-4 technology759533

stages, using a current of monochloromethyl ether,

The content of dizinylbenzene in the copolymer, % Coefficient of swelling of co-salts in solvents, ml / ml Mono; chlorine, dimethyl ether Dichloroethane Yeur chloride furyl Mete ’lal one 0.20 20 - 1 ¹ 0.25 7.5 12.5 13.0 6.8 0.50 5.5 6.0 6.5 5.0

ten

The purpose of the invention is to obtain high-strength anion exchangers of isoporous structure in the form of granules of the correct 'spherical shape and the hardening of the process terminology.

The goal is achieved by processing polyamines or their mixture with monoamines granulated linear polyvinylbenzyl chloride. It is preferable to use 5–70% solutions of polyamines in water, aliphatic hydrocarbons, and alcohols.

The proposed method is as follows. Carry out the synthesis of linear polyvinylbenzyl chloride (PVBH) in the form of spherical granules $ and then carry out the "stitching of polyvinylbenzyl chloride with the simultaneous introduction of ionic groups by treatment with polyamines or a mixture of poly- and monofunctional amine.

PVBH is obtained by suspension copolymerization of Windelbenzyl Dorida in the medium of aqueous solutions of polyvinyl alcohol, methylcellulose, polyacrylamide, polymethyl methacrylate, etc. at 70–90 ° С for 7 h.

Weak base anion exchange resins obtained by performing the amination PVBHyyLYaymyami containing primary or secondary amino group, e.g. dietilentriami 'nom, ethylenediamine, tryetylbytetramInom et al. Ily their mixtures with a variety of monofunctional primary and secondary amines (dimethylamine, di butylamine and the like).

Anion exchangers of mixed basicity are obtained by aminating PVBH with bisamines,

footgroups, for example, aminopyridines or a mixture of basic base waves (’etylendiamine) and» «н n0 $ uYHDVY1Yy трет tertiary amines (trimethylamine, pyridine, etc.).

By amination of PVBH with tertiary (Wusi polyamines, for example tetramethylmethylenediamine, tetramethylethylenediamine, tetrabuHyLethylenDYaYinOm and others _Ύ OR them with з yfyyy75yyL "yy" t with tertiary amines (trimethylamine

20

25

thirty

35

45

50

55

"ABOUT

65

pyridine, triethylamine, etc.) receive strongly basic anion exchange resin.

The degree of stitching of PVBH is regulated by the concentration of the polyamine solution or the ratio of poly-: monofunctional amy. There is an inverse relationship between the degree of stitching of PVBH and the concentration of the aminating polyamine solution. Amination is carried out in an environment of water, aliphatic alcohols and hydrocarbons at the boiling point of the solvent. The use of such solvents eliminates the dissolution of PVBH in aminating compositions.

Example 1. In a flask equipped with a stirrer and reflux condenser, 300 ml of a 2% aqueous solution of polyvinyl alcohol are placed. The solution is purged with nitrogen. In 100 g of vinyl benzyl chloride, with a chlorine content of 23.3%, 4 g of azodiisobutyrenitrile are dissolved. Smos while running the stirrer is poured into the flask and polymerized with stirring in a nitrogen atmosphere at temperatures gradually rise from 70 ^minutes to 90 C for 7 h, then cooled to room temperature. Linear PVBH in the form of spherical balls is separated from the mother liquor, washed with methanol and dried at 40–50 ° C. PVBH is soluble in aromatic hydrocarbons, acetone, dichloroethane, etc. Chlorine content 19.5%, yield 100 g

50 g of PVBH with a granule size of 0.315 • 1.4 mm are poured onto 100 ml of a 50% methayolic ethylenediamine solution, heated to 60 ° C and maintained at this temperature and stirring for hours. The resulting anioite of the net structure is insoluble in water and aqueous solutions acids and alkalis: exchange capacity for ce-ion _

4.2 mg-eq / g, specific swelling in water 2.5 ml / g, mechanical, 99% strength.

Example 2. 50 g of PVBH, obtained in example 1, is poured with 150 ml of a 50% solution of tetramethylmethylenediamine all over. It is heated with stirring for 6 hours at 90 ° C. ^ Yoiit otometochnik otytochite, washed with 3% solution of YASS and water. The exchange capacity of the anion exchanger over the ce-ion is 4.0 mEq / g with the exchange capacity for the strongly basic groups of 2.8 mEq / g. ‘Specific content of anion anion into water 3.1 ml / g, mechanical strength 98 5%. \ h ..: ·

'approx. 3. 100 g of vayylbenoneyl chloride with a chlorine content of 23.3%; they are polymerized with stirring under nitrogen atmosphere in a suspension medium of a G% SHCYO1 solution of methylcellulose. The initiator is azodium isobutyronytryl (4 g)

50 g of PVBH with a grain size of 0.3151.4 "04 and a chlorine content of 22.5% are poured with a mixture of the following composition:

10g tetramethylpropylene diamine, 60 g <

759533

pyridine and 200 ml of water and heat the cree 60 * C for b h. The resulting Strongly basic anion exchange resin has a full Exchange capacity with an E-ion (3, 5 mgV / g, specific swelling of 3.3 ml / g, mechanical strength 95.5 %

Example 4. 50 g of PVBH obtained by the method of example 3 are poured 200 ml of a 70% aqueous solution of ethylene diamine in water. The mixture is heated with stirring to 95 —10 ° C and kept at this temperature for 3 hours, then cooled and filtered. The anion exchanger is washed with 5% hydrochloric acid and water.

The resulting anion exchange resin has an exchange capacity of CC-ion 7.05 mg-eq / g, specific swelling of 4.1 ml / g and mechanical strength of 87%. The composition of the amine groups in the anion exchanger: primary 41.3%, secondary 56.6%, tertiary 2.1%.

Thus, the proposed method allows to obtain high-quality anion exchangers of an isoporous structure without using divinyl cross-linking agents, simplify the technology for producing ioporous anion-exchange resins, reducing it to 2 technological stages, producing anion exchangers with a large variety of properties, determined by the nature of the amine used for stitching AHC ·, refuse from the use of toxic monochlorodimethyl ether.

Upon receipt of anion exchange resin according to the proposed method eliminated stage

chloromethylation, associated with the need to produce monochlorine methyl ether and a large volume of reagents wrapped and disposed of *.

five

^one

Claims (2)

Claim 1. A method of producing anion exchangers by aminating with polyamines or a mixture of poly- and monoamines of polymers containing chloromethyl groups, characterized in that, in order to obtain high-strength isoporis anion exchangers; ^{5 of} the structure in the form of granules of regular spherical forms and simplification of the process technology, as polymers containing chloromethyl groups, use granular linear 20 polyvinylbenzyl chloride. 2. The method according to π. 1, the difference is that polyamines are used in the form of 5–70% solutions in water, aliphatic hydrocarbons 25 Or alcohols.