化学学报 ›› 2016, Vol. 74 ›› Issue (6): 503-512.DOI: 10.6023/A16020074 上一篇    下一篇

研究论文

Ru-B/MIL-53(AlxCr1)催化剂在苯部分加氢反应中的催化性能

窦镕飞a, 谭晓荷a, 范义秋a, 裴燕a, 乔明华a, 范康年a, 孙斌b, 宗保宁b   

  1. a 复旦大学化学系 上海市分子催化和功能材料重点实验室 上海 200433;
    b 中国石化石油化工科学研究院 催化材料与反应工程国家重点实验室 北京 100083
  • 收稿日期:2016-02-01 出版日期:2016-06-15 发布日期:2016-05-13
  • 通讯作者: 乔明华, 宗保宁 E-mail:mhqiao@fudan.edu.cn;zongbn.ripp@sinopec.com
  • 基金资助:

    项目受国家重点基础研究发展规划项目(No. 2012CB224804), 国家自然科学基金(No. 21373055), 上海市科委科技基金(No. 08DZ2270500), 北京高能所同步辐射实验室开放课题及中石化技术开发课题(S411063)资助.

Study on Ru-B/MIL-53(AlxCr1) Catalysts for Partial Hydrogenation ofBenzene to Cyclohexene

Dou Rongfeia, Tan Xiaohea, Fan Yiqiua, Pei Yana, Qiao Minghuaa, Fan Kangniana, Sun Binb, Zong Baoningb   

  1. a Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433;
    b State Key Laboratory of Catalytic Materials and Reaction Engineering, Research Institute of Petroleum Processing, SINOPEC, Beijing 100083
  • Received:2016-02-01 Online:2016-06-15 Published:2016-05-13
  • Supported by:

    Project supported by the National Key Basic Research Program of China (No. 2012CB224804), the National Natural Science Foundation of China (No. 21373055), Science and Technology Commission of Shanghai Municipality (No. 08DZ2270500), Beijing Synchrotron Radiation Facility, and the China Petroleum & Chemical Corporation (S411063).

金属-有机骨架材料不仅比表面积大、孔隙率高、孔道规则, 而且化学性质和结构性质多样、可调, 所以在近年来受到了研究者的广泛关注. 合成了MIL-53(Al)、MIL-53(Cr)及新颖的含有二元配位金属的MIL-53(AlxCr1)(x=1, 2, 3, 4)材料, 以此为载体采用浸渍-化学还原法制备了Ru-B/MIL-53催化剂, 考察了它们在苯部分加氢制环己烯反应中的催化性能. 催化剂评价结果表明, Al/Cr比不仅影响Ru-B/MIL-53催化剂上的初始反应速率(r0), 也影响环己烯的初始选择性(S0). 一般而言, 高Al含量的MIL-53作为载体对r0有利, 而含有二元配位金属的MIL-53作为载体时, S0高于仅有单一配位金属的MIL-53载体. 在环己烯选择性最高的Ru-B/MIL-53(Al3Cr1)催化剂上, r0S0分别为9.2 mmol/(min·g)和71%. 采用多种手段, 对环己烯选择性差异最为显著的Ru-B/MIL-53(Al3Cr1)和Ru-B/MIL-53(Cr)催化剂的物化性质进行了对比研究, 发现二者Ru-B纳米粒子的化学组成、电子性质、微观结构接近, 但前者的活性表面积大于后者, Ru-B粒子的尺寸更小, 分散更加均匀, 且金属-载体作用更强. 更小的Ru-B粒径不仅能够提供更多的活性位, 而且也有利于环己烯选择性的提高. 通过对反应条件进行优化, 在180 ℃和5.0 MPa H2压力下, 以100 mL乙醇胺为修饰剂时, 在Ru-B/MIL-53(Al3Cr1)催化剂上可得环己烯得率29%的结果.

关键词: 二元金属-有机骨架, 钌, 苯, 环己烯, 部分加氢

Metal-organic frameworks (MOFs) have attracted enormous research interests not only because of their merits such as high specific surface area, high porosity, and regular pore channels, but also due to their peculiarities of extremely abundant chemical and structural diversity and tunability. In this work, we synthesized MIL-53(Al) and MIL-53(Cr) containing one coordination metal and the novel MIL-53(AlxCr1)(x=1, 2, 3, and 4) MOFs containing two coordination metals as the supports for the Ru-B/MIL-53 catalysts, which were prepared by the facile impregnation-chemical reduction method. In the challenging partial hydrogenation of benzene to cyclohexene, it is revealed that the Al/Cr ratio had pronounced influences on both the initial hydrogenation rate (r0) and the initial selectivity to cyclohexene (S0). In general, MIL-53 containing a higher fraction of Al affords a higher r0, while MIL-53 containing both Al and Cr is conducive to a higher S0 than either MIL-53(Al) or MIL-53(Cr) containing only one coordination metal. On the Ru-B/MIL-53(Al3Cr1) catalyst exhibiting the highest selectivity to cyclohexene, the r0 and S0 were 9.2 mmol/(min·g) and 71%, respectively. The best Ru-B/MIL-53(Al3Cr1) catalyst and the Ru-B/MIL-53(Cr) catalyst displaying the lowest selectivity to cyclohexene were comparatively characterized to have an insight into the difference in their catalytic performance. It is found that while both catalysts had similar Ru/B molar ratio, electronic property, and microstructure, the Ru-B/MIL-53(Al3Cr1) catalyst had higher active surface area (Sact), smaller and more highly dispersed Ru-B nanoparticles (NPs), and stronger metal-support interaction than the Ru-B/MIL-53(Cr) catalyst. The smaller Ru-B NPs could not only provide more active sites for the hydrogenation of benzene, but also be beneficial to the formation of cyclohexene. By further optimization of the reaction conditions, at 180 ℃, H2 pressure of 5.0 MPa, and using 100 mL of ethanolamine as the modifier, a cyclohexene yield of 29% was obtained over the Ru-B/MIL-53(Al3Cr1) catalyst.

Key words: dual metal-organic framework, ruthenium, benzene, cyclohexene, partial hydrogenation