Synergistic catalytic effect of titanium and iron incorporated to spherical MCM-41 in selective catalytic oxidation of diphenyl sulphide with H2O2

Abstract

Spherical mesoporous silicas of MCM-41 type modified with titanium, iron or both these metals were prepared by co-condensation method and tested in the role of catalysts for selective oxidation of diphenyl sulphide with H2O2 to diphenyl sulphoxide and diphenyl sulphone. The monometallic catalysts containing titanium or iron were found to be active catalysts of diphenyl sulphide mainly to diphenyl sulphoxide. A very significant increase in catalytic activity was observed for the bimetallic samples, containing both titanium and iron. Moreover, in the case of bimetallic catalysts with higher titanium loading, diphenyl sulphone is a dominating reaction product. The increased activity of the bimetallic catalysts has been related to the synergistic operation of titanium and iron in conversion of hydrogen peroxide into reactive species, which in the next step oxidise diphenyl sulphoxide.