RUTHENIUM(III)-CATALYSED N-BROMOSUCCINIMIDE OXIDATION OF MANGANATE(VI) TO MANGANATE(VII) IN AQUEOUS ALKALINE MEDIUM

摘要

Ruthenium(III) catalysed oxidation of manganate(VI) by N-bromosuccinimide in aqueous alkaline medium is assumed to go via reductant-catalyst complex formation followed by fast steps to form products and regenerate catalyst.OBr~- and [Ru(H_2O)_6]~(3+) have been understood to be the active species of N-bromosuccinimide and Ru(III),respectively.The reaction follows a two-stage process.In both the stages it exhibits first order kinetics each in [MnO_4~(2-)] and [Ru(III)] whereas negative fractional order in [OH~-] while zero order in oxidant [NBS].Addition of products had no significant effect on the rate of the reaction.The reaction constants involved in the mechanism have been computed.There is a good agreement between the observed and calculated rate constants under different experimental conditions for both the stages of the reaction.The activation parameters were calculated with respect to the slow step of the proposed mechanism for both the stages of reaction.