Deep oxidative desulfurization catalyzed by an ionic liquid-type peroxotungsten catalyst

Abstract

New peroxotungsten anion-based ionic liquid-type catalysts were synthesized and characterized using NMR, IR, TG, etc. Then, these salts were used as catalysts for the deep desulfurization of model oil containing dibenzothiophene (DBT) with H₂O₂ as an oxidant. The effects of the temperature, H₂O₂/DBT molar ratio, and catalyst loading on the desulfurization activity have been investigated in detail. The present catalysts showed excellent desulfurization activity under solvent-free and mild reaction conditions. Moreover, this catalyst could be recycled at least ten times without any decrease in activity. It was found that the H-bonding interaction between the H2-proton in imidazolium and the basic S atom in the DBT molecule played a very important role in enhancing the catalytic activity. On the basis of the activity measurements and characterization of the catalyst, the reaction mechanism for the oxidative desulfurization process has been suggested.