N-CHLORONICOTINAMIDE OXIDATION OF METHIONINE

摘要

The kinetics of oxidation of methionine, an important, sulphur-containing essential amino acid, by N-chloronicotinamide (NCN) in the presence of 0.8 mol dm~(-3) HCl in aqueous acetic acid medium at constant ionic strength has been studied. The reaction shows fractional order with respect to substrate, inverse first order to oxidant and first order to hydrochloric acid. Addition of the reaction product, nicotinamide (NA), retarded the reaction. The rate increases with the increase in acetic acid proportion. Increase in temperature increases the rate. The activation parameters have been evaluated by studying the reaction at temperatures 300-325 K. The stoichiometry of the reaction was found to be 1:2. Molecular chlorine has been postulated as the reactive oxidising species. Methionine sulphoxide was the product. The product obtained was isolated and identified.