介孔氧化硅织构效应对铜基催化剂在草酸二甲酯催化加氢合成乙二醇反应中的影响

Textural Structure Effect of SiO_2 on the Catalytic Performance for Hydrogenation of Dimethyl Oxalate to Ethylene Glycol over Different Cu-based Catalysts

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.

A series of mesoporous SiO2 supported Cu catalysts prepared by deposition precipitation method were investigated to research the textural structure effect on the catalytic performance for hydrogenation of dimethyl oxalate （DMO） to ethylene glycol （EG）.The 100% DMO conversion and 95% selectivity can be obtained under the copper-containing catalyst synthesized by SBA-15 with regular two-dimensional hex-agonal pore structure as support.XRD,BET,H2-TPR,N2O titration and XPS were used to characterize the intrinsic essence of the catalyst.It is suggested that the dispersion of copper species and the interaction be-tween the copper species and the silica are closely related to the textural structure and play a crucial role in the hydrogenation of DMO to EG.