Deep Extractive Oxidative Desulfurization of Model Oil by Magnetically Recoverable Polyoxometalate-Based Nano Catalyst

Dibenzothiophene (DBT), benzothiophene (BT) and thiophene (T) were catalytically oxidized to their corresponding sulfone products by H2O2 in the presence of magnetically recoverable polyoxometalate-based nano catalyst. Different extracting solvents including ethanol, acetonitrile, and dimethylformamide were tested. The best results were obtained by ethanol extraction. The oxidative desulfurization (ODS) of model oils was investigated using different sulfur levels (100-1000 ppm). The removal of DBT could reach >99% and the sulfur content would be reduced from initial 100 to lower than 1 ppm, which can meet the standards of deep desulfurization. Two main aspects including the effects of nitrogen containing compounds and aromatic compounds on ODS of model oil were studied. Effect of indole, quinoline, toluene, xylene, mesitylene and naphthalene in ODS conversion were investigated. The catalyst could be easily separated from the reaction mixture using an external magnetic field, demonstrated an effective and simple separation method, and reused several times without significant change on ODS results.