催化学报

催化学报 ›› 2011, Vol. 32 ›› Issue (11): 1747-1754.DOI: 10.3724/SP.J.1088.2011.10744

• 研究论文 • 上一篇    下一篇

载体酸性对 Mo/HZSM-5-Al2O3 催化剂上烯烃歧化反应性能的影响

张大洲 1,2, 李秀杰 1,a, 刘盛林 1, 朱向学 1, 辛文杰 1, 谢素娟 1, 曾蓬 3, 徐龙伢 1,b   

  1. 1中国科学院大连化学物理研究所, 辽宁大连 116023; 2中国科学院研究生院, 北京 100049; 3中国寰球工程公司辽宁分公司, 辽宁抚顺 113006
  • 收稿日期:2011-07-19 修回日期:2011-09-02 出版日期:2011-11-14 发布日期:2015-03-30

Effects of Support Acidity on the Catalytic Performance of Mo/HZSM-5-Al2O3 Catalysts in Olefin Metathesis

ZHANG Dazhou1,2, LI Xiujie1,a, LIU Shenglin1, ZHU Xiangxue1, XIN Wenjie1, XIE Sujuan1, ZENG Peng3, XU Longya1,b   

  1. 1Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China; 2Graduate University of Chinese Academy of Sciences, Beijing 100049, China; 3China Huanqiu Contracting & Engineering Corporation, Fushun 113006, Liaoning, China
  • Received:2011-07-19 Revised:2011-09-02 Online:2011-11-14 Published:2015-03-30

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摘要： 在固定床反应器上考察了 Mo/HZSM-5-Al2O3 催化剂上乙烯与 2-丁烯歧化制丙烯反应的性能. 结合 X 射线衍射、NH3 程序升温脱附、吡啶吸附红外、H2 程序升温还原和程序升温氧化等表征结果发现, 载体酸性的差异导致催化剂酸性和 Mo 物种落位方式不同. 载体酸性较强时, 催化剂积炭严重, 反应稳定性差; 载体酸性较弱时, Mo 物种在分子筛孔道内以 (Mo2O5)2+团簇形式存在, 而在 Al2O3 表面形成较多易还原的六配位 Mo 物种, 催化活性低, 并呈现出一定的诱导期; 适中酸性的载体有利于 Mo 物种的分散和活化, 表现出了最佳的歧化反应活性.

关键词: 乙烯, ??丁烯, ??歧化反应, ??丙烯, ??载体酸性, ??HZSM-5?分子筛, ??氧化铝

Abstract: Mo/HZSM-5-Al2O3 catalyst samples, where the HZSM-5 had different Si/Al ratios (12, 42, and 213), were prepared and evaluated in a fixed-bed reactor. Effects of support acidity changes on the catalytic performance of Mo/HZSM-5-Al2O3 in the metathesis of ethene and 2-butene to propene were investigated. NH3 temperature-programmed desorption and pyridine infrared spectra revealed that the differences in support acidity led to the different anchoring modes of Mo species on the composite supports. Quick deactivation phenomena were observed on Mo/HZSM-5-Al2O3 (Si/Al = 12) due to the high acidity density of the catalyst. For Mo/HZSM-5-Al2O3 (Si/Al = 213), more Mo species dispersed on the alumina in octahedral form and those locating in the zeolite channels existed in the state of (Mo2O5)2+ clusters evidenced by ultraviolet-visible diffuse reflectance spectroscopy and H2 temperature-programmed reduction results. Such distribution was linked with the low metathesis activity and the appearance of the induction period on Mo/HZSM-5-Al2O3 (Si/Al = 213). Mo/HZSM-5-Al2O3 (Si/Al = 42) sample demonstrated the best catalytic activity and reaction stability among the three samples. This was attributed to its suitable acidity amount and optimal distribution of Mo species on the support.

Key words: ethene, butene, metathesis reaction, propene, support acidity, HZSM-5 zeolite, alumina