Oxidation of dibenzothiophene with cumene hydroperoxide on MoO3/SiO2 modified with alkaline earth metals

Catalytic oxidation of dibenzothiophene (DBT) in decalin was performed using an oil-soluble oxidant, cumene hydroperoxide (CHP), over molybdenum oxide (MoO3) supported on silica. The effects of MoO3 loading, reaction time and the molar ratio of CHP/DBT were investigated. At a MoO3 loading of 15 wt%, the conversion of DBT reached 82% at 70 °C, WHSV 30 h−1, and O/S molar ratio 3. Alkaline earth metals, such as Ca, Ba, Sr and Mg were introduced on the surface of silica, prior to the impregnation of MoO3. The results showed that the activity in the oxidation of DBT with CHP decreased in the order: MoO3/Ca-SiO2 > MoO3/Ba-SiO2 > MoO3/SiO2 > MoO3/Sr-SiO2 > MoO3/Mg-SiO2. The MoO3/Ca-SiO2 catalysts were characterized by XRD. The DBT conversions on MoO3/Ca-SiO2 catalysts with various Ca/Mo ratios were studied. When the Ca/Mo ratio was 0.05, the DBT conversion was the highest (95%) at 60 °C, WHSV 30 h−1, and O/S molar ratio 3.0.