Efficient Vapor-phase Synthesis Of 3-methylindole From Glycerol And Aniline Over Silver-based Catalysts

3-Methylindole,containing C3 indole derivatives,is a very valuable fine chemical,which is widely applied in the fields of industry,agriculture and medicine because of its high biological activity.The method for the preparation of 3-methylindole from glycerol and aniline is consistent with the idea of economic and environmental friendliness,which is the most promising method for the synthesis of 3-methylindole.This paper reported the study for the vapor-phase synthesis of 3-methylindole from aniline and glycerol over silver-based catalysts.The influence of ZnO,CeO₂ and MgO promoter on the performance of silver-based catalysts was studied through gas-solid reaction under atmospheric pressure.X-ray diffraction?XRD?,temperature programmed reduction?H2-TPR?,temperature programmed desorption of ammonia?NH3-TPD?and thermogravimetric analysis?TG?were used to characterize the catalyst,which investigated the relationship between the structure and performance of the catalysts.The results indicated that ZnO,a structural promoter,can improve the dispersion of silver on the surface of SiO₂,but increase the middle-strong acid sites.The yield of the target product reached 55%over Ag/SiO₂-ZnO with the ZnO content of 1.0 mmol/g when the catalyst was reduced 3 h at 180? and reacted 1 h at 240?.The addition of CeO₂ or MgO promoter to the Ag/SiO₂-ZnO catalyst increased the yield up to 60%.CeO₂ or MgO can not only increase the yield of 3-methylindole,but also restrain the formation of carbon deposition in the reaction,as a result,the stability of the catalyst can be improved remarkably.