Synthesis Of Immobilized ILs On Silica And Study The Properties Of Desulfurization

Because of the increasingly stringent environmental regulations, people pay moreattention to the production of clean fuels, especially petrol and diesel. The burning ofsulfide in oil releases sulfur dioxide, which contributes to acid rains andatomosphetic pollution. So desulfurization in the production of clean fuels becomesextraordinary important. In the paper, using immobilized ionic liquids (ILs) on silicagel decreases sulfur content. As a green solvent, ILs have good separation andsoluble ability to sulfide. Silica gel has large specific surface area and highadsorbability, moreover, the desulfurization using immobilized ILs on silica gelchanges liquid-liquid separation to solid-liquid separation which is convenient.Therefore, the desulfurization method which uses immobilized ILs on silica gelprovides us a new way.First,1-(triethoxy-silylpropyl)-3-methylimidazolium chloride was synthesized byrefluxing1-methylimidazole with (3-chloropropyl)trimethoxysilane. Then themethod of covalent bonding and sol-gel were adopted to synthesis immobilized ILson silica gel. The immobilised ILs with covalent bonding were analysised by IR,SEM and13C,29Si MAS NMR. And sulfur removal experiments showed the weakdesulfurization efficiency. Synthesis of four kinds of immobilised ILs via sol-gelmethod which the molar ratio of TEOS and IL was10:0,9.5:0.5,9:1,8:2, then thesamples were examined by IR, elemental analysis, SEM,13C,29Si MAS NMR andBET. The influence of temperature, contant time and the ratio of adsorbent/modelgasoline on the desulfurization were investigated. It was concluded that theoptimization operating condition were at temperature30℃, the contact time of1hand the ratio of adsorbent/model gasoline0.1. According to the structure anddesulfurization effect of the immobiled ILs, we speculated the desulfurizationmechanism.Through adsorption equilibrium experiment of immobilized ILs synthisised bysol-gel method, the thermodynamic processes were explored. The resultsdemonstrated that the adsorption process of both thiophene and2-methyl thiophene on immobilized ILs could be expressed by the Henry equation, the Langmuirequation and the Freundlich equation, while the Freundlich equation was moresuitable. Through adsorption isotherm, adsorption thermodynamic parameters, suchas enthalpy change△H, free energy change△G and entropy change△S, werecalculated. The datas showed that the adsorption process of thiophene onimmobilized ILs was exothermic, spontaneous and entropy increase, while theadsorption process of2-methyl thiophene was exothermic, spontaneous.The immobilized ILs via sol-gel method were used in fixed-bed adsorptionexperiment, that the kinetics processe were explored. The effects of temperature,space velocity and amount of adsorbent were investigated, then the breakthroughcurves were drawn. The curves were fitted with pseudo first-and second-ordermodels. It was concluded that the dynamic adsorption process of thiophene andbenzothiophene on immobilized ILs were both suitable for pseudo first-order modeland then turn to pseudo second-order model.