Nonionic micellar catalyzed oxidation of vitamins by chloramine-T in HClO4 medium:: A kinetic study

The kinetics of oxidation of vitamin B, (thiamine hydrochloride) and vitamin B-6 (pyridoxine hydrochloride) by chloramine-T (CAT) in perchloric acid medium and in presence of a non ionic surfactant (Triton x-100) have been investigated. A catalytic effect of the nonionic micelle on the rate of oxidation has been observed and rate is found to be proportional to {k' + k '' [Triton x-100]}, where k' and V are the rate constants in absence and presence of surfactant, respectively. The rate shows a first-order, a fractional order and a zero order dependence on [Chloramine-T](o), [Vitamin](o) and [H+](0), respectively in absence as well as in presence of surfactant. A mechanism involving association/binding between the oxidant and the surfactant micelle, which is supported by spectrophotometric evidence has been proposed. The binding parameters have also been evaluated using a pseudo-phase kinetic model.