Activation of Hydrogen Peroxide by Acetonitrile in the Oxidation of Thioethers: Reaction Kinetics and Mechanism

The kinetics of oxidation of diethyl sulfide (Et 2 S) with hydrogen peroxide (H 2 O 2 ) in aqueous solutions of acetonitrile (MeCN) was studied using a kinetic distribution method. It was found that the order of the reaction with respect to the substrate depends on pH and changes from the first at pH 8.06 to nearly zero at pH 11.02. The initial rates of Et 2 S consumption increase with pH and linearly depend on the concentrations of the hydroperoxide anion (HOO – ) and MeCN. It was assumed that the reaction involves the nonequilibrium formation of peroxyimidate in the slow stage of the interaction of HOO – with MeCN followed by the rapid oxidation of Et 2 S.