Electrophilic additions to alkenes. Part III. The rate equation for the reaction of 2,4-dinitrobenzenesulphenyl bromide and cyclohexene in carbon tetrachloride solution

Abstract

Increases of up to 500% in the rate of reaction of 2,4-dinitrobenzenesulphenyl bromide with cyclohexene in carbon tetrachloride solution have been obtained by the addition of 1-substituted 2,4-dinitrobenzenes. The relative catalytic activity of these compounds is 2,4-dinitroanisole > 2-bromocyclohexyl 2,4-dinitrophenyl sulphide (reaction product) > 1-chloro-2,4-dinitrobenzene. The greater increase in rate obtained with added product than with an equivalent excess of sulphenyl bromide provides an explanation for the steady increase in the value of the observed second-order velocity constant as the reaction proceeds. A rate equation is proposed for the reaction, and the mechanism discussed.