Aerobic Oxidation of Sulfides to Sulfoxides Catalyzed by Gold/Manganese Oxides

Although selective oxidation of sulfides to sulfoxides with molecular oxygen is a difficult reaction due to the overoxidation to sulfone, manganese oxides were found to catalyze the aerobic oxidation of sulfides to sulfoxides in 1,2-dichlorobenzene at 100 degrees C with a high selectivity above 99%. The catalytic activity depends on the preparation methods and conditions of manganese oxides but not on the valences of manganese. The deposition of Pd and Pt on manganese oxides was detrimental, whereas the deposition of Au enhanced the catalytic activity and selectivity.