Heterogeneous titanium catalysts for oxidation of dibenzothiophene in hydrocarbon solutions with hydrogen peroxide: On the road to oxidative desulfurization

Titanium centers grafted on hydrophobic silica bearing long chain silanes (octadecyl or octyl) are able to oxidize dibenzothiophene (DBT), as well as simpler sulfides and 2,6-dimethyldibenzothiophene, to the corresponding sulfone in hydrocarbon solution with aqueous hydrogen peroxide in only a slight excess over the stoichiometric amount, without using any surfactant or cosolvent. The productivity per gram of catalyst or per Ti site can be optimized by tuning the silanization of the silica (or using a commercially available silanized silica) and the Ti loading of the catalyst. The catalyst preparation and the oxidation reaction are compatible with the use of an industrial grade aromatic solvent.