Kinetics and mechanism of the oxidation of methionine by quinolinium chlorochromate

Abstract

The oxidation of methionine by quinolinium chlorochromate (QCC) has been studied, in the presence of chloroacetic acid, and in water–acetic acid mixtures of varying mole fractions. The reaction is first order with respect to methionine, QCC and acid. The reaction rates were determined at three different temperatures (25, 35 and 45 °C) and the activation parameters were computed. The reaction rate increased with increasing mole fraction of acetic acid in the mixture and specific solvent–solvent–solute interactions were found to predominate (81 %). A solvation model and a suitable mechanism for the reaction are postulated.

Keywords

• kinetics
• oxidation
• mechanism
• methionine