THE METHIONINE SULFONE OXIDATION BY PERMANGANATE ION (AUTOCATALYSIS): KINETIC STUDY

Abstract: A study was conducted on the reaction kinetics of methionine sulfone oxidation in an aqueous solution using potassium permanganate. The kinetic results indicated that the oxidation reaction occurs through two distinct paths: the first pathway is a non-catalyzed reaction, while the second pathway is auto-catalyzed by the product manganese (II) oxide. The rate of the first pathway reaction is determined by the first-order dependence on the concentrations of both methionine sulfone and the oxidizing agent. However, the rate of reaction of the secondary pathway is solely determined by the first-order dependence on the concentration of methionine sulfone, as well as the oxidizing and autocatalytic agent. The thermodynamic characteristics for the two pathways were determined by calculating the reaction rate constant (k) and temperature (T) dependence; this was done at various temperatures within the range of 303-323K. The rate constants of both the non-catalyzed and auto-catalyzed reactions exhibit an increase as the temperature rises. The use of Arrhenius plots facilitated the determination of thermodynamic data for the oxidation reaction by providing linear relationships. The aforementioned findings corroborate the suggested mechanism for the reaction, indicating that the rate-limiting stage of the reaction involves the transfer of a solitary electron from methionine sulfone to the permanganate ion.