Micellar and Polymer Catalysis in the Kinetics of Oxidation of L-lysine by Permanganate Ion in Perchloric Acid Medium

Abstract

Kinetics of oxidation of L-lysine by permanganate ion in a perchloric acid medium was investigated to explore the order of the reaction with respect to  oxidant and substrate and to study the catalytic behaviour of sodium lauryl sulphate (SLS) and polyethylene glycol (PEG). The reaction was found to be  first-order with respect to the oxidant and the substrate and zero-order with respect to hydrogen ion. Changes in the sodium sulphate concentration  produce a non-significant variation in the rate of the reaction. SLS and PEG were found to catalyze the reaction. Surfactant catalysis was modelled by  Piszkiewicz’s cooperativity model, while polymer catalysis was explained with the help of the Benesi-Hildebrand equation. The temperature dependence  of the rate of the reaction was elucidated, and activation parameters were obtained. Interestingly, the reaction was found to possess positive activation  entropy indicating the dissociative nature of the transition state and outer-sphere electron transfer mechanism. A mechanism of the reaction that is  supported by the experimental findings was suggested.