Fenton-like ionic liquids/H2O2system: one-pot extraction combined with oxidation desulfurization of fuel

Abstract

The extraction desulfurization (EDS) and extraction combined with oxidation desulfurization (EODS) for the removal of dibenzothiophene (DBT), benzothiophene (BT), and 4,6-dimethyldibenzothiphene (4,6-DMDBT) in a model oil were carried out in Fenton-like ionic liquids, such as [Et3NHCl]FeCl3, [Et3NHCl]CuCl2, [Et3NHCl]ZnCl2, [Et3NHCl]CoCl2, [Et3NHCl]SnCl2 and [Et3NHCl]CrCl3. The deep desulfurization could be achieved in [Et3NHCl]FeCl3 for only 5 min at room temperature. The reaction conditions such as temperature, the molar ratio of H2O2 and DBT and the amount of ionic liquid (IL) were investigated in the EODS system. By controlling the way of adding H2O2 into the desulfurization system, the sulfur content in the model oil could decrease from 500 mg L−1 to less than 10 mg L−1 at the IL/oil volume of 1 : 5. The oxidation reactivity of the different sulfur-containing compounds was found to be in the order of DBT > BT > 4,6-DMDBT. Moreover, the EODS system could be recycled ten times with a slight decrease in activity to model oil. EODS process was applied to prehydrotreated gasoline and the sulfur content could decrease from 150 to 15 mg L−1 after two rounds of reaction.