Facile Construction of Supported Polyoxometalate Ionic Liquids for Deep Oxidative Desulfurization of Fuel

A series of commercial silica-supported polyoxometalate ionic liquids ([Cnmim]3PMo12O40) with different substitutes in the imidazole ring were prepared via a facile ball milling method and employed as catalysts in the oxidative desulfurization of organosulfur compounds. The experimental results demonstrated that the active polyoxometalate center was successfully immobilized with a highly uniform dispersion on the silica. Without any organic solvent as the extractant, sulfur removal with the sample C16PMo/SiO2-BM reached 99.5% in 30 min under the optimal condition, which was ascribed to the high specific surface area and lipophilicity. In addition, the active site was verified by a free radical trapping experiment and an ESR spin capture experiment. In addition, the oxidative product was confirmed by GC-MS analysis.