The Research Of Modification And Stability Of Copper Catalysts For Acetonitrile Synthesis By Ethanol Ammoniation

Our previous research results showed that the copper catalysts prepared with co-precipitation and impregnation had high activity and selectivity for acetonitrile synthesis by ethanol ammoniation and the reaction temperature was low. However the copper loading was high and the stability was poor. In order to improve the catalyst activity with low copper loading and solve the problem of poor stability, ZrO2was selected in this research as carrier and the catalytic activity of Cu/ZrO2was investigated for acetonitrile synthesis by ethanol ammoniation. On this basis, Cu/y-Al2O2and Cu/ZrO2catalysts were also modified by the addition of Ni and the catalytic properties were investigated. We also examined the stability and the deactivation-regeneration of DYC-1catalysts. Finally the catalysts were characterized by XRD, NH3-TPD, CO2-TPD, TPR, N2O decomposition.Compared with Cu/γ-Al2O3catalysts, it is showed that Cu/ZrO2catalysts by impregnation was ideal when Cu loading was low for amination of ethanol to acetonitrile. ZrO2was in favour for forming and stabilizing Cu active centres. Furthermore ZrO2possessed not only acidic but also alkaline property which was different with γ-Al2O3. XRD and TPR patterns indicated that the presence of highly dispersed copper oxide and bulk CuO existed in Cu/ZrO2catalyst. The stability of catalyst was improved and the selectivity of acetonitrile was significantly increased by the addition of Ni element in Cu/y-Al2O3catalysts. When the Cu loading was10%and the molar ratio was1, the improvement of catalytic activity and stability was particularly obviours. It was helpful for the addition of Ni and Zn to promote the generation of bulk CuO and improved the catalyst stability. Whereas the initial activity declined by addition of Zn. The increase of Cu/y-Al2O3activity and stability was not significant when Ni was added by coprecipitation. In addition, we examined the stability of industrial catalyst DYC-1. When the reaction temperature of290℃, WHSV of0.6h-1, ammonia alcohol mole ratio of7:1, the activity of the catalyst could maintain450h. Keeping other conditions remain unchanged, when the WHSV of1.2h-1, regeneration gas was used to regenerate catalyst twice and after twice regeneration the catalyst activity could be recovered.