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用沉积沉淀法合成了不同织构特征介孔氧化硅负载的铜基催化剂,并以草酸二甲酯催化加氢合成乙二醇为探针反应考察了由不同织构特性氧化硅制备的Cu/SiO2对催化反应性能的影响,结果表明以具有二维规整六方孔道结构的SBA-15作为载体合成的Cu/SBA-15催化剂有最佳的催化性能.在反应温度为473K、压力为2.5MPa、氢酯比为50、液时空速为0.83h-1的条件下,草酸二甲酯的转化率达到100%,并且乙二醇的选择性达到95%.采用X射线粉末衍射、N2低温吸附、H2-TPR,N2O滴定、X射线光电子能谱对系列催化剂进行了系统表征,阐述了载体织构效应对催化性能影响的本质原因.研究表明以具有二维规整六方孔道结构的SBA-15作为载体能够影响活性铜物种的分散度和铜物种与载体间的相互作用,这两个为草酸二甲酯加氢合成乙二醇起关键作用的因素.
The copper-based catalysts supported on mesoporous silica with different texture features were synthesized by deposition method. The catalytic hydrogenation of dimethyl oxalate to ethylene glycol was used as the probe reaction to investigate the effect of Cu / SiO2 on the catalytic performance.The results show that the Cu / SBA-15 catalyst synthesized by using SBA-15 with two-dimensional regular hexagonal pore structure as the carrier has the best catalytic performance.When the reaction temperature is 473K, the pressure is 2.5MPa, Hydrogenate ratio of 50 and liquid hourly space velocity of 0.83h-1, the conversion of dimethyl oxalate reached 100%, and the selectivity of ethylene glycol reached 95% .Using X-ray powder diffraction, N2 low temperature adsorption, H-TPR, N2O titrimetry and X-ray photoelectron spectroscopy were used to systematically characterize the series of catalysts, and the essential reasons for the influence of the texture effect of the support on the catalytic performance were described. The results show that SBA-15 with two-dimensional regular six- Can affect the dispersibility of reactive copper species and the interaction of copper species with the carrier, both of which play a key role in the hydrogenation of dimethyl oxalate to ethylene glycol.