Chloride ion-catalysed oxidation of arginine, threonine, and glutamic acid by 1-chlorobenzotriazole: a kinetic and mechanistic study

Abstract

The kinetics of oxidation of arginine, threonine, and glutamic acid by 1-chlorobenzotriazole (CBT) were studied in HClO₄ with Cl^– ion as a catalyst at 303 K. The results are compared with those obtained with chlorine water and HOCl as oxidant. The reactions followed identical kinetics, being first-order each in [CBT] and [Amino acid] and fractional order in [Cl^–]. [H⁺] ions retard the reaction (inverse fractional order). The solvent isotope effect was studied. Variation of ionic strength and addition of the reaction product had no effect on the rate. A decrease in the dielectric constant of the medium increased the rate. Activation parameters were evaluated. A suitable mechanism consistent with the observed kinetics is proposed.