Effect of non-ionic micellar aggregates on the kinetics of oxidation of aminoalcohols by N-bromosuccinimide in alkaline medium

摘要

The kinetics of oxidation of aminoalcohols (AA) viz ethanolamine (EA),diethanolamine (DEA) and triethanolamine (TEA) by N-bromosuccinimide (NBS) in alkaline medium have been investigated in absence and in presence of polyoxyethylene (23) lauryl ether (Brij-35),a non-ionic surfactant.The kinetics showed a first order dependence of rate in NBS while the order in each AA and alkali was found to decrease from unity to zero at higher [AA] and [OH~-],respectively.The presence of small amount of surfactant strongly enhanced the rate of oxidation and the observed rate constants attained a constancy at higher surfactant concentration.The premicellar kinetics have been rationalised in the light of Piszkiewicz's positive cooperativity model.The binding constants between the reactants and the surfactant have also been evaluated using Raghvan and Srinivasan model,which is applicable for a bimolecular micellar catalysed reaction.The binding constants obtained by both the models are in good agreement.