A kinetic and mechanistic study on the silver(I) catalyzed oxidation of l-Serine by cerium(IV) in sulfuric acid medium

Abstract

The kinetics and mechanism of Ag(I) catalyzed oxidation of l-Serine by cerium(IV) in sulfuric acid media has been investigated by titrimetric technique of redox in the temperature range of 293–308 K. The reaction was first order with respect to serine, inverse order with respect to Ce(IV) and a positive fractional order with respect to Ag(I). Increase in [H+] decreased the reaction rate. The added SO42- decreased the rate of the reaction. Under the experimental conditions, the kinetically active species of cerium has been found to be Ce(SO4)2. The major oxidation product of serine has been identified as glycoldehyde which is confirmed by the IR spectrum of a corresponding hydrazone. Under nitrogen atmosphere, the reaction system can initiate the polymerization of acrylonitrile, indicating the generation of free radicals. On the basis of the experimental results, a suitable mechanism has been proposed. The rate constants of the rate determining step together with the activation parameters were evaluated.