Influence of Manganese(II) and Fluoride Ions on the Kinetics and Mechanism of Oxidation of DL-α-Alanine by Permanganate Ion in Acid Perchlorate Media

The kinetics of permanganate oxidation of DL-a-alanine in aqueous perchloric acid solution, at a constant ionic strength of 2.0 mol dm , was investigated spectrophotometrically. The reaction was found to be second- -order overall kinetics in the concentration of both reactants in the slow initial stage, but the second-order kinetics are not, however, maintained throughout the relatively fast final stage of reaction. Addition of Mn2+ ion was found to accelerate the oxidation reaction, whereas a retardation in the reaction rate was observed on addition of F" ion. This fact leads to the prediction that Mn(III) and/or Mn(IV) play an important role in the reaction kinetics. A tentative mechanism consistent with the kinetics is discussed