(33d) Ultra-Deep Desulfurization of Fuels Catalyzed by Molybdic Compound in Ionic Liquids

Sulfur compounds in transportation fuels are notoriously known to bring forth great negative problems to environment. It will be a trend to produce sulfur-free gasoline and diesel in next several years.A simplified catalytic oxidation and extractive desulfurzation (COEDS) system composed of molybdic compound (Na2MoO4?2H2O), 30% H2O2 and [Bmim]BF4 has been found suitable for the deep removal of dibenzothiophene (DBT) in diesel. The precatalyst of molybdic compound is oxidized with H2O2 to form peroxomolybdic compound, which is soluble in ionic liquid. The sulfur-containing compounds such as DBT, BT and 4,6-DMDBT in model were extracted into ionic liquid phase and oxidized to their corresponding sulfones by peroxomolybdic compound. In the case of the system containing H2O2, Na2MoO4 and [Bmim]BF4, extraction and catalytic oxidation increased the sulfur removal to 99.0%, which was remarkablely superior to mere solvent extraction with IL or catalytic oxidation without IL. The desulfurization system could be recycled five times with unconspicuous decrease in activity.