Kinetics and mechanism of ruthenium(III) catalysed and uncatalysed oxidation of ethylamine and benzylamine by N-bromosuccinimide

The kinetics of ruthenium(III) catalysed oxidation of ethylamine and benzylamine by N-bromosuccinimide in aqueous acetic acid-perchloric acid medium has been investigated. The reactions are zero order in oxidant with both substrates. Fractional order dependence on ethylamine and apparent zero order in benzylamine are observed. An inverse fractional order dependence on [H+] and first order dependence on Ru(III) are observed in the oxidation of both the substrates. The uncatalysed reactions in acetic acid-sodium acetate medium are first order in oxidant and fractional order in both the substrates. The increase in sodium acetate concentration resulted in an increase of the rate of the reaction. Suitable mechanisms and rate laws consistent with the observed kinetic results are proposed.