KINETICS AND MECHANISM OF OXIDATION OF GLYCINE BY N-BROMOPHTHALIMIDE IN THE PRESENCE OF CHLOROCOMPLEX OF Ir(III) AS HOMOGENEOUS CATALYST

摘要

For the first time, the kinetics of Ir(III)-catalysed oxidation of glycine by N-bromo-phthalimide has been studied in the presence of acetic acid-perchloric acid at constant temperature. The reaction exhibits first order kinetics with respect to N-bromophthalimide (NBP) at lower concentrations, but tending towards zero order at its higher concentrations. First order kinetics with respect to Ir(III) throughout its variation was observed in the oxidation of glycine. A positive effect was observed for [Cl~-], whereas a negative effect was observed both for [FT] and [phthalimide]. Zero order kinetics with respect to [glycine] was observed throughout its variation. The addition of [Hg(OAc)2] and change in ionic strength of medium had no significant effect on oxidation velocity, whereas the rate of reaction decrease with decrease in dielectric constant of the medium was observed in the oxidation of glycine. Kinetic and equivalent studies together with product analysis, observed effect of dielectric constant of the medium on the reaction rate, and the values of the activation parameters made the basis for the formation of a reaction mechanism for Ir(III)-catalysed oxidation of glycine by NBP in acidic medium.