Oxidative desulfurization of dibenzothiophene and diesel by hydrogen peroxide: Catalysis of H3PMo12O40 immobilized on the ionic liquid modified SiO2

Here we reported an oxidative desulfurization system for oxidation of sulfur-containing compounds in model oil and diesel by catalysis using SiO2-supported phosphomolybdate hybrid material with 30% H2O2 aqueous solution as the oxidant. Firstly, The SiO2 was modified with 1-propyl-3-triethoxysilyl 3-methylimidazolium chlorid by grafting method. We used the Si-29 MAS NMR to demonstrate that the organic silane group was attached to the SiO2 surface by one or two Si-O-Si bonds. Secondly, the phosphomolybdate was immobilized onto the modified SiO2 to prepare the hybrid material catalyst. The FT-IR, UV-vis, and TG characterization results indicate that the Keggin structure of the [PMo12O40](3-) and imidazole ring were remained. The catalyst was used to oxidative desulfurization of dibenzothiophene by H2O2 as the oxidant. Maximum oxidation activity was observed at a loading of 30 wt.% H3PMo12O40 which can complete oxidation 0.2 wt.% of dibenzothiophene at 50 degrees C and an O/S molar ratio of 3.0 in 30 min. The catalyst could be easily separated by centrifugation and reused for seven times without any deactivation. The high performance of this oxidative desulfurization system was verified in the sulfur removal from a real diesel oil by oxidation followed by dimethylformamide extraction. (C) 2018 Elsevier B.V. All rights reserved.