Cu-Zn-Fe/SiO2催化剂用于乙酸加氢酯化的研究

摘要

研究添加助剂Fe制得的Cu-Zn-Fe/SiO2催化剂在乙酸酯化加氢反应中的催化性能。对不同Fe的添加量、反应温度、压力、液空速度（LHSV）下的反应结果的考察表明，Cu-Zn-7%Fe/SiO2催化剂（相对于载体SiO2，Fe的质量分数为7%）在325℃、1.9 MPa、LHSV为0.6 h-1、H2与乙酸的物质的量比为20的条件下的催化反应效果最好，乙酸的转化率达到100%，乙酸乙酯的选择性达到79.7%。X 射线衍射（XRD）分析表明，适量的Fe加入使催化剂在还原后出现了新相（Fe2O3，ZnFe2O4和Fe），同时改变了催化剂上Cu晶相的分散度及结晶度，从而提高了催化剂的活性。添加了7%Fe助剂后，Cu-Zn-Fe/SiO2催化剂对乙酸乙酯的选择性提高了7.8%，在15 h内的催化稳定性也同时提高。%Gas phase catalytic hydroesterification of acetic acid over Cu-Zn-Fe/SiO2 catalysts was studied. Influences of Fe content, reaction temperature, pressure and liquid hourly space velocity(LHSV) on catalytic activity were investigated. The results indicated that a high conversion of acetic acid of about 100% was achieved with a relatively high selectivity(79.7%)to ethyl acetate over Cu-Zn-7%Fe/SiO2 under conditions of 325℃, 1.9 MPa,LHSV 0.6 h-1 and molar ratio of H2 to acetic acid 20. X-ray diffraction(XRD) analysis showed that the addition of a moderate amount of Fe introduced new phases, namely Fe2O3, ZnFe2O4 and Fe to the catalyst after reduction. The addition of Fe changed the dispersity and crystallinity of Cu phase and hence changed in catalytic activity. The addition of 7%Fe into Cu-Zn/SiO2 improved the stability of the catalyst in 15 hours , and improved the selectivity of ethyl acetate by 7.9%.