Silica-gel Supported V Complexes: Preparation, Characterization and Catalytic Oxidative Desulfurization

In this manuscript, a series of catalyst SGn-[VVO2-PAMAM-MSA] (SG=silica gel, PAMAM=polyamidoamine, MSA=5-methyl salicylaldehyde, n=0, 1, 2, 3) was prepared and their structures were fully characterized by Fourier transform-infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and inductive coupled plasma emission spectrometer (ICP) etc. XPS revealed that the metal V and SGn-PAMAM-MSA combined more closely after the formation of Schiff base derivatives. Their catalytic activities for oxidation of dibenzothiophene were evaluated using tert-butyl hydroperoxide as oxidant. The results showed that the catalyst SG2.0-[VVO2-PAMAM-MSA] presented good catalytic activity and recycling time. Meanwhile, the optimal condition for the catalytic oxidation of SG2.0-[VVO2-PAMAM-MSA] was also investigated, which showed that when the oxidation temperature was 90 °C, time was 60 min, the O/S was 3U1, and the mass content of catalyst was 1%, the rate of desulfurization could reach 85.2%. Moreover, the catalyst can be recycled several times without significant decline in catalytic activity.