Low-temperature and low-pressure fuel hydrodesulfurization by solid catalyst coupling with ionic liquids

A new process for fuels hydrodesulfurization (HDS) utilizing solid catalyst coupled with ionic liquids (ILs) at mild operating conditions is proposed in this study. A novel Ce-Ni-Mo/γ-Al2O3 catalyst with high catalytic activity was developed and coupled with different ILs i.e. (1-Butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF4), 1-butyl-2,3-dimethylimidazolium tetrafluoroborate ([BDMIM]BF4), 1-ethyl-3-methyl imidazolium tetrafluoroborate ([EMIM]BF4), and 1-butyl-3-methylimidazolium chloride salt ([BMIM]Cl)) to investigate the removal of Sulfur (S) from dibenzothiophene (DBT) used as model oil. Then the highly efficient IL [BMIM]BF4, coupled with the solid catalyst was selected to undergo a series of parallel experiments to investigate the effects of temperature, hydrogen pressure and IL/oil mass ratio toward S removal. Moreover, the IL system could be recycled four times without a significant decrease in desulfurization activity. The supposed mechanism of HDS reaction was also explained. This study can be deemed as new approach for getting cleaner fuels based on the complementary usage of ILs with solid catalysts at mild operating conditions.