Selective sulfoxidation reactions with H₂O₂ catalyzed by Ti-containing SBA-15 materials

This contribution relates the behavior of Ti-SBA-15 catalysts in the sulfoxidation reaction with hydrogen peroxide under mild conditions (40–70 °C). Ti-SBA-15 samples with 1, 3 and 5 wt% of TiO₂ have been prepared by grafting SBA-15 silica with Ti(OⁱPr)₄ in ethanol followed by calcination. Due to their mesopores, the Ti-containing catalysts accommodated large molecules like methyl-phenyl-sulfide, diphenylsulfide and dibenzothiophene, which were selectively oxidized into their corresponding sulfoxides and sulfones. The turnover frequency was correlated with the amount of the tetrahedral Ti atoms in the catalyst. During the oxidation process performed in batch mode, with acetonitrile or ethanol as solvent, the catalyst topology and texture were preserved, but the nature of the Ti species suffered some changes.