焙烧温度对CuMgAl催化剂催化糠醛气相加氢制糠醇性能的影响

采用分步沉淀过程制得质量比m(CuO)∶m(MgO)∶m(Al_2O_3)为25∶26∶49的CuMgAl类水滑石前驱体,经过不同温度焙烧制得CuMgAl-t催化剂。通过BET、热重、XRD、H_2-TPR和CO_2-TPD对催化剂进行表征,在固定床中考察CuMgAl-t催化剂催化糠醛气相加氢制糠醇的性能。结果表明,焙烧温度影响催化剂活性、稳定性及对产物的选择性,低温焙烧的催化剂经还原后可获得较多活性中心,高温焙烧的催化剂表面具有更多的碱性位,CuMgAl催化剂经450℃焙烧表面存在适宜的活性中心和碱性位。在常压、反应温度180℃、氢醛物质的量比5∶1、糠醛体积空速0.3h~(-1)的条件下,CuMgAl-450催化剂上糠醛的转化率和糠醇的选择性分别达到98.64%和97.66%。

Effect of calcination temperature on the catalytic performance of CuMgAl catalysts for furfural gas phase selective hydrogenation to furfuryl alcohol

The CuMgAl hydrotalcite-type precursors were prepared by fractional precipitation process with the mass ratio of m(CuO):m(MgO):m(Al₂O₃)=25:26:49. CuMgAl-t catalysts were calcined at various temperatures. CuMgAl-t catalysts were characterized by BET, TGA, XRD and H₂-TPR and CO₂-TPD. The catalytic performance of CuMgAl-t catalysts for the gas phase hydrogenation of furfural to furfuryl alcohol was investigated in a fixed bed reactor. The results showed that the calcination temperatures had effect on catalysts activity, stability and product selectivity. The lower temperature calcined catalysts with reduction can obtain more active center and the higher temperature calcined catalysts had more alkaline sites on the surface of catalysts. CuMgAl catalyst calcined at 450℃ had suitable surface active centers and alkaline sites. Under the reaction conditions of atmospheric pressure, reaction temperature of 180℃, molar ratio of hydrogen to furfural of 5 and volume space velocity of 0.3 h^-1, the furfural conversion of 98.64% and furfuryl alcohol selectivity of 97.66% were reached over the CuMgAl-450.