Oxidative Desulphurization of 4,6-Dimethyldibenzothiophene with Hydrogen Peroxide over Ti-HMS

摘要

Oxidative desulphurization of 4,6-dimethyldibenzothiophene (DMDBT) in octane has been investigated with hydrogen peroxide (H_2O_2) over Ti-HMS under mild conditions. Among the several Ti-containing catalysts, Ti-HMS exhibits high catalytic activity for the oxidation of DMDBT. The effects of the amount of the Ti-HMS catalyst, the mole ratio of H_2O_2 and the S-containing molecule (H_2O_2/S), the concentration of DMDBT, and the temperature on the reaction rate were investigated. The reaction rate of the oxidative desulphurization was promoted with the increase of the amount of the catalyst, the H_2O_2/S mole ratio, the concentration of DMDBT, as well as the temperature. The Arrhenius apparent activity energy of the oxidative reaction of DMDBT with H_2O_2 over Ti-HMS was determined as 38.54 kJ mor~(-1). The reaction system H_2O_2/Ti-HMS shows a high intrinsic catalytic activity for sulfur-containing cpmpounds present in diesel in the following order: DMDBT < benzothiophene (BT) < dibenzothiophene(DBT). BT and DBT can be completely converted into their corresponding sulfoxides and sulfones in 3 h. The removal of DMDBT can be achieved by nearly 90%, and as a result, the sulfur level of a model fuel can be lowered from 226.1 to 22.9 ppm with a H_2O_2/S mole ratio of 4:1 at 333 K.