GB808844A - Improvements relating to anion-exchange resins - Google Patents

Abstract

Anion-exchange resins containing two or more nitrogen atoms in each anion-exchange group are prepared by reacting a cross-linked polymer containing halo-alkyl groups, e.g. chloromethylated cross-linked polystyrene or copolymers of polystyrene with divinyl benzene or ketone, with a o -mono or o -dialkylamino alkyl halide and an amine. The reaction may take place directly by mixing the three reactants, or in stages in which an intermediate is obtained (1) by reacting the polymer with the amino alkyl halide, preferably b -methyl amino or b -ethyl amino ethyl chloride, and then with a primary, secondary or tertiary amine to introduce secondary, tertiary or quaternary nitrogen atoms respectively; (2) by reacting the polymer with a primary or secondary amine and then with the alkyl halide derivative in the presence of a base, e.g. caustic soda. The resins may combine weakly basic with strongly basic properties and may be further alkylated to convert secondary and tertiary groups to tertiary or quaternary groups respectively. In examples, beads of a chloromethylated copolymer of divinyl benzene were swollen with benzene and reacted with b -diethylamino ethyl chloride at 30 DEG C., cooled, boiled and washed with dilute hydrochloric acid, and water to give an intermediate which was heated with di- or trimethylamine solution and washed to yield final resins containing a tertiary and quaternary or two quaternary nitrogen atoms respectively. Specification 779,994 is referred to.