Heteropolyanion-Based Ionic Liquid for Deep Desulfurization of Fuels in Ionic Liquids

A heteropolyanion-based ionic liquid, [(3-sulfonic acid) propylpyridine](3)PW12O40 center dot 2H(2)O, [PSPy](3)PW12O40 center dot 2H(2)O abbreviated [PSPy](3)PW, was synthesized and approved as an effective catalyst for desulfurization of Fuels in [omim]PF6 by using aqueous H2O2 as oxidant. The catalysis was fulfilled with advantages of high activity, simplified workup, and flexible recyclability. The catalytic oxidation reactivity of sulfur-containing compounds was in the order dibenzothiophene (DBT) > 4,6-dimethyldibenzothiophene (4,6-DMDBT) > benzothiophene (BT). The effects of the amount of [[PSPy](3)PW, H2O2, and reaction time and temperature were investigated in detail. Under the optimal conditions, the removal of DBT achieved 99.4%. Especially, we found that the removal of 4,6-DMDBT could be up to 98.8%, and the system could be recycled at least 9 times without significant decrease in activity. The sulfur level of FCC gasoline could be reduced from 360 to 70 ppm in the extraction and catalytic oxidation system.