Cu-Zr-Co-O催化剂催化乙醇直接合成乙酸乙酯

分别采用反滴加共沉淀法、正滴加共沉淀法、溶胶-凝胶法合成了Cu-Zr-Co-O催化剂,并研究了该催化剂在乙醇脱氢合成乙酸乙酯反应中的催化性能;对催化剂试样进行了XRD、XPS、N2物理吸附、H2-TPR和NH3-TPD表征,并考察了催化剂预还原温度、反应温度、GHSV对反应性能的影响。表征和实验结果显示,采用反滴加共沉淀法合成的Cu-Zr-Co-O催化剂(CP-N(1))具有较大的比表面积,催化剂表面Cu0粒径较小,且表面存在较多的酸中心;预还原温度影响催化剂表面Cu0的数量及粒径大小,在300℃下预还原的CP-N(1)催化剂对乙醇脱氢合成乙酸乙酯反应具有最佳的催化性能,在GHSV=1.2min-1、200℃的优化条件下,乙醇转化率达85.0%,乙酸乙酯选择性达80.2%。

Direct Synthesis of Ethyl Acetate from Ethanol over Cu-Zr-Co-O Catalysts

Cu-Zr-Co-O catalysts were prepared by reverse titration coprecipitation,normal titration coprecipitation and sol-gel method,separately.The synthesis of ethyl acetate through the dehydrogenation of ethanol on the catalysts was studied.The catalysts were characterized by means of XRD,XPS,N2physisorption,H2-TPR and NH3-TPD.The influences of prereduction temperature,reaction temperature and GHSV on the catalytic performances of the catalysts were investigated.The characterization results suggested that the Cu-Zr-Co-O catalyst(CP-N(1)) prepared by the reverse titration coprecipitation possessed larger specific surface area,smaller Cu0 particle size and more surface acid sites.The prereduction temperature affects the conversion of ethanol and the selectivity to ethyl acetate evidently due to its effects on the amount and partical size of Cu0 on the catalyst surface.Under the optimized reaction conditions of CP-N(1) prereduced at 300 ℃ as the catalyst,GHSV 1.2 min-1 and reaction temperature 200 ℃,the conversion of ethanol and the selectivity to ethyl acetate reached 85.0% and 80.2%,respectively.