Oxidation of methionine by sodium N-chlorotoluene-p-sulphonamide in aqueous solution: a kinetic study

Abstract

Kinetics of oxidation of DL-methionine (Mt) in the presence of HCl, HClO₄, H₂SO₄, and NaOH by sodium N-chlorotoluene-p-sulphonamide (CAT) have been investigated at 30 °C (and 35 °C in alkaline medium) and the results are compared with those obtained with HOCl as the oxidant, in acid medium. The reactions follow identical kinetics, being first order each in [CAT] and [H⁺] and zero order in [substrate]. In alkaline medium the rate shows first-order dependence each on [CAT] and [Mt]. An Inverse fractlonal order is noted in [OH^–]. Studies of solvent isotope effects using D₂O showed a retardation of rate both in acid and alkaline media. The derived rate laws are consistent with the observed kinetics.