Kinetics of the Oxidation of Methyl Phenyl Sulfide by Hydrogen Peroxide in the Presence of Hydrocarbonate Anion

The oxidation of methyl phenyl sulfide in water and water-alcohol mixtures takes place both by a noncatalytic mechanism and with the participation of hydrogen peroxide as catalyst; in the presence of ammonium hydrocarbonate it takes place by a mechanism involving HCO₄⁻ as a more active oxidant than hydrogen peroxide (>100 times). In water-alcohol media (ethylene glycol, isopropyl alcohol, tert-butanol) the rate decreases in the order H₂O > EG > IPA > TBA. The reactivity of organic sulfides varies in the following way: MeSPh ≈ EtSPh << Et₂S. The results were interpreted from the standpoint of a molecular mechanism of oxidation of the sulfide with H₂O₂ and HCO₄⁻ through a polar transition state, containing the HOX molecule (X = H, OH, OR) as acid-base catalyst.__________Translated from Teoreticheskaya i Eksperimental’naya Khimiya, Vol. 41, No. 2, pp. 94–99, March–April, 2005.