Construction Of Polymeric Ionic Liquid-heteropoly Acid Composite Based Emulsion Systems And Their Application On Catalytic Desulfurization

Pickering emulsions are formed by solid particles that adsorbed on the oil-water interface,and has the characteristics of a large two-phase contact surface area and easy-to-separate the catalyst.Pickering emulsions have been widely used in food,biomedicine,cosmetics and other fields.The solid particles not only have the emulsifying properties,but also can load some functional substances,and then serve as Pickering emulsifier to stabilize Pickering emulsion.Heteropolyacid is a substance with acid catalysis function.The polymerized ionic liquid heteropolyacid complex formed by using ionic liquids to support heteropolyacid,has a surface-active property,which can be used as an acid-catalyzed dual-functional emulsifier for acid-catalyzed reactions in emulsions.Therefore,the subject based on the acid catalytic performance of heteropolyacids at the interface based on Pickering emulsion is worth investigating.In this paper,polymerized ionic liquid heteropolyacid salts are formed by sulfonic acid-based imidazole-based polymerized ionic liquids and heteropolyacids by electrostatic attraction,which can be used as emulsifiers to emulsify the simulated oil to form Pickering emulsions,and then conduct an interfacial catalytic oxidative desulfurization system.The specific research contents are as follows:1.Study on the preparation of polymerized ionic liquid phosphomolybdate and its emulsification properties.Firstly,poly 1-vinyl-3-propane sulfonic imidazole is synthesized,and then poly 1-vinyl-3-propane sulfonic imidazole phosphomolybdate is obtained by electrostatically complex with phosphomolybdic acid,the surface and emulsification properties were analyzed using infrared spectrum,Zeta potential,optical microscope,scanning electron microscope and so on.The experimental results showed that when the molar ratio of the polymerized ionic liquid monomer to phosphomolybdic acid is 4:1,the obtained polymerized ionic liquid phosphomolybdate can be used as an emulsifier to emulsify the water-toluene system and form a stable oil-in-water Pickering emulsion.The emulsion shows a certain acidity,and has pH sensitivity,which cannot be stable under neutral and alkaline conditions.The microscopic morphology of the polymerized ionic liquid phosphomolybdic acid emulsifier at the interface was studied in the water-paraffin system.As the molar ratio of the polymerized ionic liquid monomer to phosphomolybdic acid gradually decreased,the morphology of emulsifier changes from stringy sheet to layers of stacked sheet.2.Study on the preparation of polymeric ionic liquid phosphotungstate and the desulfurization of catalytic oxidation model oil.Firstly,poly?1-vinylimidazole-3-propanesulfonyl imidazole?phosphotungstate is prepared,which can be used to prepare an oil-in-water Pickering emulsion by emulsifying a model oil-water system that were mainly composed by n-heptane.The model oil-water emulsions can be stabilized by using poly 1-vinyl-3-propane sulfonyl imidazole phosphotungstate when the molar ratio of the polymerized ionic liquid monomer and phosphotungstic acid is 1:1.In this system,the phosphotungstic acid can be brought to the interface,and due to its catalytic performance,the desulfurization effect of the emulsion was investigated.The experimental results show that the best desulfurization results reached with the conditions of 60?,H₂O₂ and sulfur mass ratio of 160 for 6 h,and the desulfurization rate can reach 98.8%.The catalyst can be separated by centrifugation,and the performance does not decrease significantly after6 cycles.