Oxidation of a mixture of thiophene, benzothiophene and dibenzothiophene with hydrogen peroxide using supported Pd, Cr2O3, unsupported manganese oxides and a commercial Co-Mo/Al2O3 as catalysts has been studied in a mixture of hexadecane and acetonitrile. Based solely on the conversion of each organic sulfur compound, the ranking of catalyst efficiency found was: supported Pd > Cr2O3 manganese oxides approximate to Co-Mo/Al2O3. The influence of the calcination temperature on synthesized manganese oxides was also investigated. Mn3O4, amorphous manganese compounds, Mn2O3 and MnO2 showed a similar catalytic activity independent of the hydrogen peroxide concentration. According to these preliminary results, it seemed that the catalyzed decomposition of the hydrogen peroxide competes with the oxidative desulfurization, however, at short reaction time (10 min) conversions at around 60-70% of thiophene were reached. (c) 2005 Elsevier B.V. All rights reserved.