Kinetic Investigations on Pd(II) Catalyzed Oxidation of Some Amino Acids by Acid Bromate

Abstract

Kinetic  investigations  on  Pd(II)  catalyzed oxidation  of  dl-serine and  dl-threonine  by  acidic  solution of  potassium  bromate  in  the presence  of  mercuric  acetate,  as  a  scavenger  have  been  made in  the  temperature  range of 30–45°C. The rate shows zero order kinetics in bromate [BrO₃‾] and order of reaction is one with respect to substrate and Pd(II) respectively. Increase in [Cl‾] showed positive effect, while [H⁺] showed zero effect. Negligible effect of mercuric acetate and ionic strength of the medium was observed. A transient complex, formed between [PdCl₂]  and amino acid. Palladium chloride [PdCl₂] being reactive species of Palladium (II) chloride in 1:1 ratio, disproportionates in a slow and rate determining step. Various activation parameters have been calculated. A suitable mechanism in agreement with observed kinetics has been proposed.