| 3-Methyltetrahydrofuran is not only an important intermediate,but also can be used as a clean fuel component with a promising market prospect.However,there are many disadvantages in the traditional production processes of 3-methyltetrahydrofuran.A new process for preparing 3-methyltetrahydrofuran by catalytic hydrogenation of trimethyl 1,1,2-ethanetricarboxylate was proposed based on the bifunctional catalysts composed of copper-based catalysts and solid acid catalysts.The process is simple with less enviromnental pollution and have a good prospect for development.The effects of different supports(ZrO2,SiO2,Al2O3)on the catalytic activity of copper-based catalyst were studied.All the supports can improve the catalytic performance compared with Cu-ZnO catalyst,and Cu-ZnO-Al2O3 catalyst has an appropriate Cu0/Cu+ molar ratio of about 1 with highly dispersed copper species and small crystallite size of copper species,so it exhibits the highest hydrogenation activity.The influences of different solid acid catalysts(HZSM-5,SAPO-34,HY,?-Al2O3)on the performance of bifunctional catalysts were investigated.Cu-ZnO-Al2O3/?-Al2O3 bifunctional catalysts show the highest selectivity of target product,and Py-IR characterization results indicate that Lewis acid site are responsible for the selective formation of 3-methyltetrahydrofuran.The optimial solid acid catalyst content is 25 Wt%.The effects of the preparation methods on the performance of the bifunctional catalyst were studied.Compared with physical mixing method,grinding mixing method and coprecipitation impregnation method,the coprecipitation sedimentation method not only facilitates the interaction between the both component,but also the two catalytically active centers do not cover each other,which is conducive to exerting a synergistic effect.Under the optimized reaction conditions of P=2 MPa,T=290?,H2/ester molar ration-40,WHSV=0.75 h-1,the yield of 3-methyltetrahydrofuran was up to of 56%. |
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