Abstract

MECHANISTIC OXIDATION OF CYANOCOBALAMIN (VIT-B12) BY POTASSIUM PERMANGANATE IN ACIDIC MEDIUM

A.B. Teradale, M. S. Yadawe and S. D. Lamani*

Abstract

The kinetics of oxidation of [CCA] by permanganate in acidic medium at a constant ionic strength of 0.054 mol dm-3 has been studied spectrophotometrically. The reaction between permanganate and CCA in acidic medium exhibits 1:3 stoichiometry. The reaction shows first order in permanganate and has less than unit order dependence each in both [CCA] and [H+] and retarding effect of [MnO4 -] under the reaction conditions. The reaction is shown to proceed via a [CCA] complex, which decomposes in a rate-determining step to give intermediates followed by fast step to give the products. The reaction constants involved in the different steps of the mechanisms were calculated. The activation parameters with respect to slow step of the mechanism were computed and discussed. The thermodynamic quantities were also determined for the reaction.

Keywords: Cyanocobalamin, potassium permanganate, kinetic oxidation, double beam spectrophotometer.