Kinetics and Mechanism of Palladium (II) Catalyzed Oxidation of D-(+) Galactose by Cerium(IV) in Aqueous Acidic Medium

Abstract

Kinetics of palladium (II) catalyzed oxidation of D-(+) galactose by cerium (IV) have been studied titrimetrically in aqueous acidic medium in the temperature range 308-333 K. The reaction has been found to be first order with respect to D-(+) galactose in catalyzed reactions. The rate of reaction decreases with increasing sulphuric acid. The reaction proceeded through formation of an intermediate complex, which was proved by kinetic method. The observed stoichiometric ratio was 1:2 in the oxidation of D-(+) galactose. From the effect of temperature on the rate of reaction, the Arrhenius equation and various activation parameters have been computed. Arabinose and formic acid have been identified as main oxidation products of the reaction. A plausible mechanism from the results of kinetic studies, reaction stoichiometry and product analysis has been proposed.