催化学报

催化学报 ›› 2011, Vol. 32 ›› Issue (6): 957-969.DOI: 10.1016/S1872-2067(10)60223-9

• 研究论文 • 上一篇    下一篇

溶胶凝胶法制备的 Cu/SiO2 催化剂及其催化草酸二甲酯加氢反应

林凌, 潘鹏斌, 周张锋, 李兆基, 杨锦霞, 孙明玲, 姚元根*   

  1. 中国科学院福建物质结构研究所结构化学国家重点实验室, 福建福州 350002
  • 收稿日期:2011-01-10 修回日期:2011-03-03 出版日期:2011-06-21 发布日期:2014-10-31

Cu/SiO2 Catalysts Prepared by the Sol-Gel Method for Hydrogenation of Dimethyl Oxalate to Ethylene Glycol

LIN Ling, PAN Pengbin, ZHOU Zhangfeng, LI Zhaoji, YANG Jinxia, SUN Minling, YAO Yuangen*   

  1. State Key Laboratory of Structural Chemical Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, Fujian, China
  • Received:2011-01-10 Revised:2011-03-03 Online:2011-06-21 Published:2014-10-31

PDF

1772

摘要： 采用溶胶凝胶法制备了用于草酸二甲酯加氢合成乙二醇的 Cu/SiO2 催化剂, 在优化的反应条件下, 当催化剂中 Cu 含量为 15%~25% 时, 草酸二甲酯转化率和乙二醇选择性分别达到 99.9% 和 95.0%. 通过 N2 吸附-脱附、透射电镜、X 射线衍射、氢气程序升温还原、N2O 滴定法和 X 射线光电子能谱等手段对各 Cu/SiO2 催化剂进行了表征. 结果表明, 在相同反应条件下, 随着 Cu 含量增加, 硅胶对活性物种的包裹作用和 Cu 物种间的团聚作用对催化剂活性影响较大, 当 Cu 含量 ≤ 10% 时, 硅胶对 Cu 物种的包裹作用强烈, 是影响催化剂活性的主要因素; 当 Cu 含量 >10% 时, 催化剂表面 Cu 物种间的团聚作用变得突出, 成为影响催化剂活性的主要因素, 二者的消长对催化剂表面结构、活性物种的形态和化学环境的影响很大, 并最终影响催化剂的性能.

关键词: 溶胶凝胶法, 草酸二甲酯, 加氢, 铜, 二氧化硅, 乙二醇, 包裹作用, 团聚作用

Abstract: A series of Cu/SiO2 catalysts for the hydrogenation of dimethyl oxalate to ethylene glycol were prepared by the sol-gel method. Under optimized hydrogenation conditions, dimethyl oxalate conversion and ethylene glycol selectivity were found to reach 99.9% and 95.0%, respectively, upon varying the copper loading between 15% and 25%. The prepared catalysts were characterized by N2-physisorption, transmission electron microscopy, X-ray diffraction, H2-temperature-programmed reduction, N2O titration, and X-ray photoelectron spectroscopy. The results show that when the copper loading was increased under the same experimental conditions the factors that mostly affect the activities of the catalysts prepared by the sol-gel method are encapsulation and agglomeration. The encapsulation of silica is strong and it becomes the major factor when w(Cu) ≤ 10% while agglomeration among the copper species on the catalyst surface becomes more serious and is a major factor when w(Cu) > 10%. These two factors influence the surface structure, the morphology of the copper species, and the chemicals surroundings the catalysts and as a result the performance of the catalysts is affected too.

Key words: sol-gel method, dimethyl oxalate, hydrogenation, copper, silica, ethylene glycol, encapsulation, agglomeration