Desulfurization of Oil Using Ionic Liquids as Phase Transfer Catalysts

In this work, kinds of ionic liquids based on dialkylimidazolium and N-alkyl-pyridinium cations were was prepared. The ionic liquids were employed as phase-transfer catalysts (PTCs) for phase-transfer catalytic oxidation of dibenzothiophene (DBT) dissolved in n-heptane, The partition ratios of DBT to ionic liquids and n-heptane were investigated. Then H2O2(30%) was used as oxidant, DBT was oxidized without the presence of PTCs, the oxidation desulfurization rate was only about 13%. While PTCs and H2O2 were introduced together, the desulfurization rate of DBT was increased apparently. When IL([C4mpy][HSO4]) was used as PTC, and the condition were: temperature is 50°C, the time is 30min, H2O2/sulfur mol ratio (O/S) is 6, the desulfurization rate reached the maximum (92.7%). The PTC [C4mpy][HSO4] can be recycled for 4 times without significant decrease in activity.