Oxidation of pyruvic acid by Cobalt (III)

Abstract

The kinetics of oxidation of pyruvic acid sodium pyruvate by Co3+ in sulphuric and nitric acid media, and the effects of [ Co2+], [So3 4-] and temperature on the reaction rates have been studied. The reaction is biomolecular, the order with reference to [substrate] and [Co3+] being unity. The reaction rates vary inversely with [H+]. Increased in ionic strength and [HSO-4] retards the rates. From the result of kinetic studies it is inferred that CoOH2+ ions are active in HNO3 medium while in H2SO4 medium Co3+ ions also are active along with CoOH2+ ions. The stoichiometry of the reaction has been found to be 2Co2+ per mole of organic substrate ; acetic acid and carbon dioxide are the products. A free radical reaction mechanism involving fission at caorbonyl group folllowed by subsequent oxidation of carbonyl free radical to acetic acid has been proposed and the rate laws derive. The various reaction rate parameters have been evaluated and discussed.