Kinetics of oxidation of some α‐amino acids L(−) arginine, L(−) histidine, L(+) ornithine, L(−) tryptophan, L(−) threonine by sodium N‐chloro‐4 methyl benzene sulphonamide (chloramine‐T) in alkaline medium

Kinetic studies of oxidation of L(−) arginine, L(+) ornithine, L(−) histidine, L(−) tryptophan, L(−) threonine have been carried out in alkaline medium. The reaction showed an inverse fractional order in OH− and first‐order dependence on both amino acid and chloroamine‐T concentration. The effect of varying ionic strength (KCl) on the rate of oxidation is negligible. A general mechanism for the oxidation has been suggested by considering interaction between anionic species of amino acid and p‐toluene‐sulphochloramide. The effect of solvent and temperature have been also discussed. The fractional order obtained in OH− is due to the fact that a fraction of overall reaction proceeds via an alternative OH− independent path. The combined rate law in accordance to observed kinetics is derived as The rate constants predicted by the derived rate law as the concentration of OH− ions change, are in excellent agreement with the observed rate constants, thus further justifying these rate laws and hence the proposed mechanistic schemes.