| As an important indole derivative,3-methylindole could synthesize a series of importantnitrogen-containing heterocyclic chemical. The application of3-methylindole wasconsiderably widespread in the fields of industry,agriculture and medicine owing to the thirdactive site of3-methylindole. The one-step vapor-phase catalytic synthesis of3-methylindoleover Cu/SiO2-Al2O3catalyst from low-cost aniline and biomass-derived glycerin is the mostpromising route because it meets the rule of atom economy of chemical reaction.In this paper, the effect of CeO2promoter on the catalytic performances and structure ofCu-based catalysts supported over different SiO2-Al2O3carriers for the vapor-phase synthesisof3-methylindole from aniline and glycerol was studied. The Cu-based catalysts wereprepared by sequential incipient wetness impregnation. The catalysts were characterized byX-ray diffraction, transmission electron microscopy, H2temperature-programmed reduction,NH3temperature-programmed desorption, thermogravimetric and differential thermalanalysis to investigate the Cu-based catalysts doped with CeO2promoter and supported overdifferent SiO2-Al2O3carriers.The results indicated that the addition of CeO2promoter to three kinds of SiO2-Al2O3carrier supported-Cu/SiO2-Al2O3catalysts could increase the activity, selectivity and stabilityto some extent because adding CeO2promoter increased the amount of the weak acid sitesand inhibited the sintering of copper during the reaction. Among them, Cu-CeO2/SiO2-Al2O3catalyst, which the Si/Al was10and the particle size was20-40mesh on the SiO2-Al2O3support, exhibited high activity and selectivity, as well as good stability. The yield of3-methylindole was up to46%at fifth hour. The reason is that the dispersion of Cu particles onthe support was good, the amount of the weak acid sites was more and the amount of themiddle-strong acid sites was fewer. The addition of CeO2promoter did not decrease the cokeon the surface of the Cu-based catalysts. |
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