Kinetics and Mechanism of the Oxidation of Sulphite Ion by Di-μ-oxo-tetrakis (2, 2’ bipyridine)-Dimanganese (III, IV) Perchlorate in Aqueous Acidic Medium.

Abstract

The kinetics and mechanism of the oxidation of sulphite ion (SO32-) by di-μ-oxo-tetrakis (2, 2’ bipyridine)-dimanganese (III, IV) perchlorate ([MnIIIO2MnIV]3+) has been investigated in aqueous acidic medium. A mole ratio of 2:3 was observed for this system. Pseudo - first order reaction was first order with respect to [MnIIIO2MnIV]3+ and first order with respect to [SO32-] system. The rate constant increased as the concentration of the acid increases. Changes in ionic strength were observed to decrease with increase in concentration. The reaction did not induce polymerization of acrylamide and the presence of added cations (Mg2+ and Ni2+) or anions (HCOO- and NO3-) did not affect the rate. Michaelis-Menten’s plot was linear without an intercept. Based on the results of the spectroscopic investigation and lack of interaction with added ions, the reaction is said to have proceeded via Proton Coupled Electron Transfer for [MnIIIO2MnIV]3+/SO32- system.KEYWORDS: Kinetics, Mechanism, Oxidation, di-μ-oxo-tetrakis, Sulphite Ion.