Free Radical Induced Oxidation of L-Cystine by Alkaline Permanganate - A Kinetic Study

Abstract The kinetics of oxidation of L-cystine by alkaline permanganate follows the rate law, where Κ is the formation constant for the complex between L-cystine and permanganate and k is the decomposition rate constant. The data suggest that the oxidation of L-cystine proceeds via the formation of a complex between L-cystine and permanganate which decomposes slowly, followed by a fast reaction between the free radical of L-cystine and another molecule of permanganate to give the products. The reaction constants involved in the mechanism are derived. There is good agreement between the observed and calculated rate constants under varying experimental conditions. The activation parameters are computed with respect to the slow step of the mechanism.