KINETICS AND MECHANISM OF IRIDIUM(III) CATALYZED OXIDATION OF ALIPHATIC-AMINES BY N-BROMOSUCCINIMIDE

Kinetics or Ir(III) catalysed oxidation of primary aliphatic amines (ethylamine, n-propylamine and n-butylamine), secondary amine (diethylamine) and tertiary amine (triethylamine) by N-bromosuccinimide (NBS) in perchloric acid medium and in presence of mercuric acetate have been studied. During a particular kinetic run the order of reaction in NBS is found to be unity. However, a decrease in the rate constant was observed with an increase in the initial NBS concentration. A near zero order dependence of rate with respect to substrate was observed The rate is proportional to {k'+k''[Ir(III)]}. where k' and k'' are the rate constants for uncatalysed and catalysed path respectively. The effect of acid is negligible in case of primary aliphatic amines while a retarding effect of acid was observed in case of diethylamine and triethylamine. The effect of [NaClO4] and [Succinimide] on the rate of oxidation was negligible. A retarding effect of [acetic acid] and [NaCl] on the reaction rate has also been observed. A suitable mechanism consistent with the kinetic data has been proposed.