Chemical and Textural Characteristics of Chlorosulfonated Porous Styrene—Divinylbenzene Copolymer Beads

Abstract

The influence of chlorosulfonation on textural and chemical characteristics of porous styrene—divinylbenzene copolymer prepared with varying diluent composition (n-heptane and 2-ethyl-1-hexanol mixture) and divinylbenzene content has been investigated in this study. The obtained porous supports are treated with a 40 vol.% chlorosulfonic acid solution in 1,2-dichloroethane. Textural studies of the copolymer show that after chlorosulfonation, the porous volume remains constant at low ethyl hexanol and divinylbenzene content, then varies from 50% ethyl hexanol content in the diluent mixture and 20% DVB content. Comparing before and after chlorosulfonation, the porous volume and apparent density are observed not to vary at low 2-ethyl-1-hexanol and divinylbenzene content but to vary for copolymers with high DVB and prepared with a high ethyl hexanol content in the diluent mixture. Chemical analysis reveals that chlorosulfonation reaction is a two-step reaction leading to the formation of both sulfonyl and chlorosulfonyl derivatiés and the optimum total group content is obtained for copolymer prepared with 10% DVB and 80/20 n-heptane/ethyl hexanol mixture as diluent. The content ratio of the chlorosulfonyl and sulfonyl groups also depends on the diluent composition and divinylbenzene content used in the preparation of the beads.