The Application Of Ionic Liquids In Olefins Removal And Desulfurization From Petroleum Products

This work mainly involved the investigation of the application of ionic liquids (ILs) in olefins removal and desulfurization from petroleum products. The SO3H-functionalized ionic liquids ([C3SO3Hmim]Br-ZnCl2and [C3SO3Hmim]Cl-ZnCl2) and imidazolium-based phosphoric ionic liquids ([Mmim]DMP,[Emim]DEP and [Bmim]DBP) were synthesized. And the structures of the synthesized ionic liquids were characterized by FT-IR,1H NMR,13C NMR and ESI-MS. The properties of ionic liquids, such as, viscosity, thermostability and acidity, were also measured. The SO3H-functionalized ionic liquids were used for removal of trace olefins from aromatics (referred to as oil), and the results showed that [C3SO3Hmim]Br-ZnCl2(X=0.67, X referred to as the molar fraction of ZnCl2in the ionic liquids) ionic liquid exhibited a better performance for olefins removal. When the stirring speed was600rpm, with a mass ratio of IL/oil of0.2, the olefins conversion could reach29.54%after the reaction had taken place at373K for1h. The application of imidazolium-based phosphoric ILs in removal of dimethyl disulfide from model oil via extraction was also studied, and the optimum conditions for desulfurization were obtained. The optimal mass ratio of IL/oil was1.0, the appropriate extraction temperature was298K, and the suitable extraction time was60min. Under the optimum extraction conditions, the sulfur removal ability of the phosphoric ionic liquids followed the order of [Bmim]DBP≥[Emim]DEP>[Mmim]DMP. It was also observed that the model oil was soluble in the ionic liquids, but the ionic liquids could be reused at least five times after a reactivation treatment. Finally, the imidazolium-based phosphoric ILs were used as extractants to remove4,6-dimethyldibenzothiophene from model oil coupled with catalytic oxidation. The results demonstrated that the desulfurization system with [Bmim]DBP ionic liquid exhibited the best performance for desulfurization. When the mass ratio of catalyst to oil was0.02, after the reaction had taken place at323K for3h, the sulfur removal of89.20%was obtained with the mass ratio of IL/oil of0.2and the mass ratio of H2O2/oil of0.04. After the [Bmim]DBP ionic liquid was reused six times, the sulfur removal could still reach87.98%.