Kinetics and Mechanism of uncatalysed and Chloridecatalysed Oxidative Decarboxylation of Glycine and Aspartic Acid by Chloramine- T in Perchloric Acid Medium

Department of Post-Graduate Studies and Research in Chemistry, Mangalore University, Mangalagangothri-574 199

Manuscript received 17 June 1986, raised 18 March 1987, accepted 23 July 1987

The kinetics of oxidative decarboxylation of glycine and L-aspartic acid by chloramine-T has been investigated both in the absence and presence of chloride ion in perchloric acid medium. In the absence of chloride ion, the rate followed second order kinetics in [CAT]_o, first order in [substrate], inverse first order in [H⁺] with both the amino acids. Chloride was found to enhance the rate of oxidation and affect the kinetics. In the presence of chloride, the rate followed first order kinetics in [CAT]_o in both cases. But the rate was fractional and zero order in [substrate] with glycine and aspartic acid, respectively. The kinetic order in was also different, 8\(\epsilon\). inverse fractional order and fractional order respectively with glycine and aspartic acid. The effect of chloride was more pronounced with aspartic acid. Effects of added reaction product and the variation of ionic strength and dielectric constant of the reaction medium have also been investigated. Reaction schemes in conformity with the observed kinetics have been proposed and the related rate laws derived. The constants of the rate limiting and other steps have been calculated in some cases.