Oxidative Desulfurization of Fuels Catalyzed by Fenton‐Like Ionic Liquids at Room Temperature

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.