Supported Heteropoly Acid Ionic Liquid Catalytic Oxidation Desulfurization

The quantity demand of fuel oil is increasing with the rapid increase of economy,it has been an exigent mission to reduce the sulfur content in fuel oil.Nowadays,hydrodesulfurizationismainlyappliedindieselfuel desulfurization.However,non-hydrodesulfurizationprocess,especiallyoxidative desulfurization,could be more attractive based on the cost saving and environmental protection.Three kinds of ionic liquid are synthesized with the combination of phosphotungstic acid in this paper,supported and non-supported phosphotungstic acid ionic liquids are prepared as two series of catalyst,characterized by ¹H NMR,BET,FT-IR,XRD,TGA and SEM.Experiments on the desulfurization of model oil containing dibenzothiophene catalytic oxidation with extraction were conducted under various catalytic conditions,using H₂O₂ as oxidation and N-methylpyrrolidone as extraction agent and screening out the optimal catalyst.The most suitable desulfurization condition was obtained based on the research of oxidative desulfurization reaction.Finally,we compared the activation energy by the study of dynamics with and without the existence of catalyst.The results showed that[C₁imCH₂CH₂COOH]₃PW₁₂O₄₀?IL1-HPW?exhibited the highestcatalyticactivityamongthethreekindsofnon-supported catalysts.[C₁imCH₂CH₂COOH]₃PW₁₂O₄₀/?-Al₂O₃?IL1-HPW/?-Al₂O₃?,whichwas made by co-precipitation method showed the best catalytic effect compared with the other two catalysts with different carrier.The results showed that under the optimum condition which the dosage of the catalyst is 0.7 wt%,the loading of catalyst is 30%,the reaction time is 60 min,n?H₂O₂?:n?S?=2.5:1,the reaction temperature is 50?and extracted only once,the desulfurization rate reached to 99.2%,the order of desulfurization activity of model oil which contained different sulfur compounds is DBT>4,6-DMDBT>BT when using IL1-HPW/?-Al₂O₃ as the catalyst.Catalytic oxidation desulfurization was performed on straight-run diesel oil using IL1-HPW/?-Al₂O₃ as catalyst,the sulfur content decreased from 477 mg/L to 24.4mg/L,with a high desulfurization rate of 94.88%.The dynamic study showed that this catalytic oxidation reaction is first-order reaction and the activity energy of the reaction was 14.56 KJ/mol with catalyst otherwise it is 27.36 KJ/mol,indicating that the sulfur compounds could be removed efficiently from model oil under this catalytic system.