Oxidation of DL - Methionine by Imidazolium Chlorochromate and Benzimidazolium Chlorochromate in Aqueous Perchlorate Medium

The oxidation of methionine by oxidants such as imidazolium chlorochromate (ICC) and benzimidazolium chlorochromate (BCC) in aqueous perchlorate medium has been studied spectrophotometrically over the range 3.00 ≤ 10 3 (methionine) ≤ 6.00, 0.01 ≤ (H + ) ≤ 0.03 mol dm -3 and 20 0 C ≤ T≤ 40 0 C. The rate of reaction was found to increase with the increase of total concentration of methionine and total concentration of H + . The reaction was found to exhibit first order dependence in (methionine), (H + ) and the oxidants (ICC) and (BCC). The ΔH ≠ (kJ/mol) and ΔS ≠ (JK -1 mol -1 ) for the electron transfer reaction were found to be 12.5 and -154.1 in case of ICC and 17.53 and -136.9 in case of BCC respectively. The product of the reaction was found to be methionine sulphoxide. The negative values of ΔS ≠ support ordered transition state for both the electron transfer reactions due to ICC and BCC.