Deep Catalytic Oxidative Desulfurization of Model Fuel Based on Modified Iron Porphyrins in Ionic Liquids: Anionic Ligand Effect

The modified iron porphyrins with weak ligand (PF6–, BF4–) were prepared by a gentle and cheap approach. The catalytic systems with modified iron porphyrins and 1-butyl-3-methylimidazolium hexafluorophosphate ([Bmim]PF6) were used in the catalytic oxidative removal of sulfur compounds from model oil under mild conditions. The effect of anionic axial ligand on catalytic oxdative desulfurization performance was investigated. Iron porphyrins with weak ligand exhibited higher desulfurization performance, and the catalytic ability of catalysts was FeIIITPP(PF6) > FeIIITPP(BF4) > FeIIITPPCl. A dual active model mechanism was proposed to illustrate this phenomenon of oxidative process. The system of FeIIITPP(PF6) and [Bmim]PF6 could be recycled for 6 times without evident decrease of desulfurization efficiency.