Performance Study In Catalytic Oxidation Desulfurization With Molecular Oxygen Of Ionic Liquid-Heteropoly Acid Materials

In recent years,the acid rain and photochemical smog pollution which were leaded to the SOx from the burning of fuel of sulfur-containing compounds damage the ecological environment.It is a research hot spot to reduce the content of sulfur-containing compounds in oil in petroleum chemical industry.As the standard of sulfur content is more severe in the world,the limitations of the traditional hydrodesulfurization(HDS)is becoming more and more serious.Hence,oxidation desulfurization(ODS)arose gradually in the sights of the researchers because of its mild conditions and high desulfurization efficiency.In this work,based on green pollution-free oxygen as the oxidant,we combined different ionic liquids and heteropoly acids to explore the efficient and durable oxidative desulfurization catalyst which can make oxygen oxidation desulfurization research have further development.Firstly,the catalyst 1-butyl-3-methyl imidazole phosphorus molybdenum vanadium catalyst([C3H3N2(CH3)(C4H8)]5PM10V2O40,hereinafter referred to as[C4Mim]5PM10V2O40)was systhesised by the self-assembly method using the reaction of 1-butyl-3-methyl imidazole ionic liquids and phosphorus molybdenum vanadium.The catalyst was characterized by X-ray Diffraction(XRD),Scanning Electron Microscopy(SEM),Fourier Transform Infrared Spectroscopy(FT-IR)and Thermogravimetric Analysis(TG),1H-Nuclear Magenetic Resonance(1H-NMR).The performance of the catalyst was evaluated in the reaction of catalytic oxygen oxidation desulfurization in model fuel.The experiment results show that the addition of imidazole ionic liquids improved the catalyst lipophilicity so making its dispersed more evenly that improve the catalytic activity of the catalyst on the basis of keeping phosphomolybdic acid Keggin structure.The DBT removal rate can reach 93.4%at the dosage catalyst of 0.05 g(0.45 wt%mass fraction),the initial reaction temperature of 125?,oxygen pressure of 0.2 MPa,reaction time of 4 h.There was no significant decline after the catalyst using five recycle time.In order to reduce the reaction temperature and pressure,we preparared iron-containing N-methyl pyrrolidone molybdophosphoric acid catalyst(hereinafter referred to as NMPFePMo)considering the possible adverse reactions which lead by high temperature and the certain requirement in the reaction for high pressure equipment.The catalyst was characterized by X-ray Diffraction(XRD),Scanning Electron Microscopy-Energy Disperse Spectroscopy(SEM-EDS),Fourier Transform Infrared Spectroscopy(FT-IR),Thermogravimetric-Differential Thermal Analysis(TG-DSC).The performance of the catalyst was evaluated in the reaction of catalytic oxygen oxidation-extraction desulfurization in model fuel with polyethylene glycol-600 as the extraction agent.The experiment results show that the catalyst maintained the Keggin structure of phosphomolybdic acid and perfence higher catalytic activity.The DBT removal rate can reach 98.5%at the extraction time of 0.5 h,reaction time of 6 h,reaction temperature of 80?,dosage of catalyst of 0.05 g,simulation oil volume of 15 mL,extractant volume of 10 mL,oxygen flow rate of 40 mL/min.There were certain effect on DBT removal rate but hardly any changes in the end when some toluene,cyclohexane,1-octene were added in the reaction respectively represent for real typical hydrocarbon compounds in fuel.The catalyst has good reusability and there was no apparent decline after the catalyst using eight times consecutively.