Kinetics and mechanism of oxidation of aromatic sulfides and arylmercaptoacetic acids by N-chlorosuccinimide

Abstract

Kinetic measurements of the oxidation of divalent organic sulfur compounds by N-chlorosuccinimide in acetonitrile–water mixture at constant [H+] show that the reaction is first order in both the oxidant and the organic sulfur compound. While the rate of oxidation of methyl phenyl sulfide or diphenyl sulfide increases with [H+], that of phenylmercaptoacetic acid decreases. Therefore it has been concluded that protonated N-chlorosuccinimide and N-chlorosuccinimide are the active oxidising species in the oxidation of aromatic sulfides and N-chlorosuccinimide is the active species in the case of phenylmercaptoacetic acids. Structure–reactivity correlations for the oxidation of aryl methyl sulfides, diaryl sulfides and arylmercaptoacetic acids result in a high negative reaction constant, providing evidence for the formation of a chlorosulfonium ion intermediate.