Debromination of di- and tetrabrominated compounds by crosslinked poly{1-[ p-(mercaptomethyl)phenyl]ethylene}

Abstract

Poly{1-[ p-(mercaptomethyl)phenyl]ethylene} with a low content of divinylbenzene units as the crosslinking component was prepared from chloromethylated poly(styrene-co-divinylbenzene), and the activity of the thiolate form in the debromination reactions of 1,2-dibromocyclohexane was investigated with respect to the analytical content of the -SH groups. The extent of transformation of the -SH groups into the thiolate form, and the degree of crosslinking of the polymeric carrier were investigated. An almost complete conversion of 1,2-dibromocyclohexane and high yields of cyclohexene were obtained by using polymeric thiols with the initial DVB contents of 1 or 2%; the degree of functionalization of the carrier 100% or 30–60%; and the reaction times of polymeric thiols with sodium methoxide in methanol (1–2h). The debromination reaction required 5h for completion. Under optimum conditions, debromination of 1,2,5,6-tetrabromocyclooctane, α,β-dibromoethylbenzene, α,β,3,4-tetrabromoethylcyclohexane, diethyl2,3-dibromosuccinate and stilbene dibromide gave olefins in yields of 60–100%