GB845055A - Sulphonium anion exchange resin - Google Patents

Abstract

Sulphonium anion exchange resins are prepared by reacting a resinous polymer containing from 75 to 99,5% by weight of chloro- or bromo-methyl substituted monovinyl aromatic monomer and 0,5 to 25% of a diethylenically unsaturated cross-linking agent e.g. divinyl benzene, with an equimolar proportion of a dialkyl, dihydroxyalkyl or an alkylhydroxy alkyl sulphide wherein the alkyl radicals contain from 1 to 4 carbon atoms and the hydroxyalkyl radicals contain from 2 to 4 carbon atoms, and recovering the polymeric sulphonium halide. The polymers may be chloro- or bromomethylated cross-linked polymers or copolymers of styrene, vinyltoluene or xylene, chloro- or dichlorostyrene, vinyl naphthalene and acenaphthene; chlorinated or brominated cross-linked polymers or copolymers of vinyl toluene, dimethyl styrene and vinyl mesitylene; and polymerized and cross-linked vinyl benzylchloride and bromide, and dimethylvinyl benzyl chloride and bromide. The reaction is carried out by refluxing beads of the polymer, at between 20 and 100 DEG C., preferably in the presence of swelling agents such as ethanol, methylene dichloride, (others are listed), with excess of a sulphide of general formula R2S where R represents an alkyl group of 1 to 4 carbon atoms or hydroxyalkyl groups of 2 to 4 carbon atoms and which may include dimethyl, diethyl, dipropyl, dibutyl, methylhydroxyethyl, di(hydroxyethyl, propyl and butyl), and diisopropyl sulphides. The resin is recovered by filtering and washing.