Abstract
Oxidation of the sulfur‐containing compounds benzothiophene (BT), dibenzothiophene (DBT), and 4,6‐dimethyldibenzothiophene (4,6‐DMDBT) has been studied in a desulfurization system composed of model oil, hydrogen peroxide, and different types of ionic liquids [(C~8~H~17~)~3~CH~3~N]Cl/FeCl~3~, [(C~8~H~17~)~3~CH~3~N]Cl/CuCl~2~, [(C~8~H~17~)~3~CH~3~N]Cl/ZnCl~2~, [(C~8~H~17~)~3~CH~3~N]Cl/SnCl~2~, [(C~4~H~9~)~3~CH~3~N]Cl/FeCl~3~, [C~10~H~21~(CH~3~)~3~N]Cl/FeCl~3~, [(C~10~H~21~)~2~(CH~3~)~2~N]Cl/FeCl~3~. Deep desulfurization is achieved in the Fenton‐like ionic liquid [(C~8~H~17~)~3~CH~3~N]Cl/FeCl~3~ at 25 °C for 1 h. The desulfurization of DBT reaches 97.9 %, in consuming very low amount of [(C~8~H~17~)~3~CH~3~N]Cl/FeCl~3~ (only 0.702 mmol). The reaction conditions, for example, the amount of [(C~8~H~17~)~3~CH~3~N]Cl/FeCl~3~ or H~2~O~2~, the temperature, and the molar ratio of FeCl~3~ to [(C~8~H~17~)~3~CH~3~N]Cl, are investigated for this system. The oxidation reactivity of the different sulfur‐containing compounds is found to decrease in the order of DBT>BT>4,6‐DMDBT. The desulfurization system can be recycled six times without significant decrease in activity. The sulfur level of FCC gasoline could be reduced from 360 ppm to 110 ppm.