PROCESS FOR THE PRODUCTION OF ION EXCHANGE RESINS

1,274,361. Suspension polymerization; producing ion exchangers. CHEMIEKOMBINAT BITTERFELD VEB. 16 March, 1970, No. 12556/70. Heading C3P. Ion exchange resins are prepared by introducing ion exchange groups into polymers which have been produced by suspension polymerizing at least one monovinyl compound with at least one polyvinyl compound at between 50‹ and 100‹ C., the monomers having added thereto (a) at least 10% by weight of the monomers, of at least one non-swelling adjuvant which dissolves the monomers but neither dissolves nor swells the polymer and (b) at least 10% by weight of the monomers, of at least one swelling adjuvant which dissolves the monomers and which swells the polymer without dissolving it, (a) and (b) being organic compounds which are liquid at ambient temperature, chemically inert to the polymerization system, insoluble in water and substantially non-volatile at the polymerization temperature. The adjuvants are preferably removed after polymerization by drying, extraction or steam distillation. Adjuvant (a) may be for example an aliphatic hydrocarbon or an alcohol, and adjuvant (b) may be for example an aromatic hydrocarbon, an alkylated aromatic hydrocarbon, a halogenated hydrocarbon or a ketone. Monovinyl compounds specified are styrene and its derivatives, and acrylic acid and its derivatives. Polyvinyl compounds specified are divinyl benzene, ethylene glyool diacrylate and triacryloyl-perhydrotriazine. The preferred method involves mixing the adjuvants with the monomers and then subjecting the mixture to suspension polymerization with the usual additives and initiators. The examples use as adjuvants (a) and (b) respectively, a commercial mixture of aliphatic hydrocarbons and diethylbenzene or toluene, the polymers prepared being styrene/divinyl benzene copolymers, which are converted after polymerization, to ion exchange resins by chloromethylation with monoohloro dimethyl ether and then reaction with tri- or dimethyl amine, and an ethyl acrylate/divinyl benzene copolymer which is saponified to produce a cation exchanger. The terms "swelling adjuvant" and "non-swelling adjuvant)' are defined in the Specification.