SU449917A1 - The method of obtaining amphoteric ion exchanger - Google Patents

Description

(54) METHOD FOR OBTAINING AMPHOTERIC IONITES

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This invention relates to methods for producing ion exchange resins used to extract various elements from solutions and slurries.

A known method of producing amphoteric IONITS by carboxyalkylating with halo-acids polymers with primary amino groups is based on ammonium-chlorinated methylated styrene-divinylbenzene copolymer. You get an ion exchanger with amphoteric properties.

The nitrogen content in polystyrene-based anion exchangers is 5–8%; therefore, the exchange capacity of ampholyte for carboxyl groups is relatively low (not higher than 5–8 mEq / g).

To improve the exchange capacity and complexing, with the ability of amphoteric IONITS according to the proposed method, a polymer matrix with a higher content of primary nitrogen (15-25%) is used for their synthesis.

According to the proposed method, amphoteric ion exchangers are obtained by halocarboxylation of polymers containing their primary amino groups, obtained on the basis of copolymers of acrylonitrile and divinylbenzene by means of nitrile groups (reduction).

The proposed ampholyte preparation process consists of the following stages: the preparation of an acrylonitrile / divinylbenzene copolymer; obtaining anion exchange resin with primary amino groups; carboxyalkylation of anion exchange resin by halo acids.

Example. A mixture of 117 ml of acrylonitrile, 21.9 ml of technical divinylbenzene (DVB content 56% by weight, ethylstyrene 44% by weight),

53.8 ml of alkyl bepzine, 1.5 g of benzoyl peroxide are poured with stirring into 420 ml of saturated sodium chloride solution containing 4.2 g of potato starch. The mixture is heated with stirring for 4 hours at 62 ° C and

2 h at 90 ° C. Upon completion of the reaction, the granules of a porous copolymer of acrylonitrile and divinylbenzene are filtered, washed with water and dried. Then 50 g of copolymer is poured 200 ml

n percent solution of caustic sodium. The mixture is heated to 60 ° C and kept at this temperature for 2 hours. After cooling to room temperature, 200 ml of bromine water is introduced into the mixture with stirring, heated to boiling and allowed to stand until carbon dioxide evolution ceases. After cooling and filtration, the anion exchange resin is washed with water and dried.

Thereafter, the anion exchange resin is suspended in 2 liters of a 10% solution of chloroacetic acid, the pH of the suspension is adjusted to 9 with sodium hydroxide and heated on a steam bath, adjusting the pH periodically until the pH ceases to change. Then the granules obtained ampholyte washed with water. The exchange capacity of the ampholyte by carboxyl groups (by Na-ion) is 11.5 mg-eq / g. CU SOY 78 mg / g; Soy on Cr 250 mg / g.

Subject invention

The method of obtaining amphoteric ion exchangers by carboxyalkylating with halides of polymers containing amino ciia6OCOCBBbie, characterized in that the product of reduction of acrylonitrile and divinylbenzene copolymer is used as polymers with weak basic amino groups to increase their exchange capacity.