物理化学学报 >> 2010, Vol. 26 >> Issue (06): 1585-1592.doi: 10.3866/PKU.WHXB20100606

催化和表面结构 上一篇    下一篇

Au/Ti-MCM-41(H)催化丙烯气相直接环氧化

刘义武, 余欢, 张小明, 索继栓   

  1. 中国科学院成都有机化学研究所, 成都 610041; 中国科学院研究生院, 北京 100049
  • 收稿日期:2009-11-06 修回日期:2010-02-10 发布日期:2010-05-28
  • 通讯作者: 张小明 E-mail:xm.zhang@cioc.ac.cn

Direct Gas-Phase Epoxidation of Propylene over Au/Ti-MCM-41(H) Catalysts

LIU Yi-Wu, YU Huan, ZHANG Xiao-Ming, SUO Ji-Shuan   

  1. Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu 610041, P. R. China; Graduate University of Chinese Academy of Sciences, Beijing 100049, P. R. China
  • Received:2009-11-06 Revised:2010-02-10 Published:2010-05-28
  • Contact: ZHANG Xiao-Ming E-mail:xm.zhang@cioc.ac.cn

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摘要：

采用纳米组装法制备了一系列不同Ti含量的具有微孔-介孔复合结构(hybrid)的钛硅分子筛Ti-MCM-41(H)载体, 继而用沉积-沉淀法制得纳米金催化剂. 通过粉末X射线衍射(XRD)、氮气等温吸附-脱附、傅里叶变换红外(FT-IR)光谱、紫外-可见漫反射(DR UV-Vis)光谱、透射电镜(TEM)及等离子体原子发射光谱法(ICP-AES)对催化剂进行了表征, 并考察了纳米金催化剂在氢气/氧气共存条件下丙烯气相直接氧化制环氧丙烷反应中的催化性能. 结果表明: 合成的微孔-介孔复合结构的钛硅分子筛Ti-MCM-41(H)具有典型的MCM-41 结构, Ti(IV)以高分散的形式存在于分子筛的骨架结构中. 在常压、423 K反应温度下, 以Ti/Si摩尔比为1%的Ti-MCM-41(H)为载体制备纳米金催化剂表现出了最佳的催化性能, 反应30 min, 丙烯的转化率达5.4%, 环氧丙烷的选择性为74.2%, 环氧丙烷的生成速率为73.1 g·h-1·kg-1; 反应330 min后, 丙烯的转化率为4.9%, 环氧丙烷的选择性为67.3%.

关键词: 丙烯环氧化, 微孔-介孔复合分子筛, 纳米金催化剂, 环氧丙烷

Abstract:

Microporous-mesoporous hybrid Ti-MCM-41(H) was successfully synthesized by the nano-cluster assembling method. Gold nano-particles were prepared by the deposition-precipitation method. The samples were characterized by powder X-ray diffraction (XRD), nitrogen isothermal adsorption-desorption, Fourier transforminfrared (FT-IR) spectroscopy, diffuse reflectance UV-Vis (DR UV-Vis) spectroscopy, transmission electron microscopy (TEM) and inductively coupled plasma emission spectrometry (ICP-AES). The catalytic performance of the gold nano-particles was evaluated by the direct gas phase epoxidation of propylene using hydrogen and oxygen. Results revealed that the Ti-MCM-41(H) had a typical mesoporous MCM-41 structure. The results also suggested that isolated Ti(IV) was introduced into the siliceous framework of the support material. Superior catalytic performance was obtained with the gold catalyst supported on Ti-MCM-41(H) in which the Ti/Si molar ratio was 1%. Propylene conversion reached 5.4% at the initial 30 min with 74.2% propylene oxide (PO) selectivity and produced rate 73.1 g·h-1·kg-1. The conversion and PO selectivity were 4.9%and 67.3%after running 330 min on streamat 423 K.

Key words: Propylene epoxidation, Microporous-mesoporous hybrid zeolite, Nano-gold catalyst, Propylene oxide