催化学报

催化学报 ›› 2011, Vol. 32 ›› Issue (1): 155-161.DOI: 10.3724/SP.J.1088.2011.00921

• 研究论文 • 上一篇    下一篇

介孔载体负载 Pt 催化剂上 α-酮酸酯的不对称氢化

陈志坚, 李晓红, 李灿   

  1. 中国科学院大连化学物理研究所催化基础国家重点实验室, 辽宁大连 116023
  • 收稿日期:2010-09-17 修回日期:2010-10-12 出版日期:2011-01-13 发布日期:2014-05-22

Enantioselective Hydrogenation of α-Ketoesters on Mesoporous Matrix Supported Platinum Catalysts

CHEN Zhijian, LI Xiaohong, LI Can*   

  1. State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China
  • Received:2010-09-17 Revised:2010-10-12 Online:2011-01-13 Published:2014-05-22

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摘要： 以介孔材料 SBA-15、经或未经 Al2O3 修饰的具有三维立方孔道结构的 SiO2 为载体, 制备了负载型 Pt 催化剂, 并用于催化 α-酮酸酯底物 2-氧代-4-苯基-丁酸乙酯 (EOPB) 和丙酮酸乙酯 (Etpy) 的不对称氢化反应中. 结果表明, 当 SBA-15 孔径由 6.2, 7.6 和 9.2 nm 依次增加时, EOPB 不对称氢化的活性和手性选择性有所提高, 氢化 ee 值分别为 22.0%, 36.0% 和 50.0%. 两类拥有三维立方孔道结构的 SiO2 载体负载的 Pt 催化剂性能明显优于 SBA-15 负载的, 表明传质或空间位阻因素对 EOPB 不对称氢化的手性选择性和反应活性影响很大. 以 Al2O3 修饰的介孔硅为载体时, 相应的 Pt 催化剂上 EOPB 氢化手性选择性最高 (ee 79.3%), 且具有高氢化活性; 用于丙酮酸乙酯不对称氢化反应时, 活性和手性选择性 (ee 值达 90.2% 以上) 均较高. 由此可见, Al2O3 修饰的三维立方介孔硅结构的复合纳米材料是一种新型的多相手性催化剂载体, 具有良好的应用前景.

关键词: 介孔载体, 铂催化剂, 辛可尼啶, 手性修饰, 2-氧代-4-苯基-丁酸乙酯, 丙酮酸乙酯, 不对称氢化

Abstract: The asymmetric hydrogenation of ethyl 2-oxo-4-phenyl-butyrate (EOPB) over the Pt catalysts modified by cinchonidine using mesoporous SBA-15, cubic mesoporous silica, and Al2O3 modified cubic mesoporous silica as matrix was studied. The results showed that in the channels of mesoporous SBA-15, the enantioselectivity and conversion are enhanced in larger sized channels compared to those of the hydrogenation in smaller sized channels. When the channel size of SBA-15 increases from 6.2 nm to 7.6 nm and to 9.2 nm, the hydrogenation ee is 22.0%, 36.0%, and 50.0%, respectively. The ee (53.8%) on the cubic mesoporous silica support is obviously higher than that (36.0%) on the SBA-15 support with similar channel size, and the ee on the Al2O3 modified cubic mesoporous silica support reaches 79.3%. These facts showed that the mass transfer or steric clash has important impacts on the enantioselectivity and conversion of the enantioselective hydrogenation of EOPB. In the enantioselective hydrogenation of ethyl pyruvate, the Al2O3-grafted cubic mesoporous silica supported Pt catalyst exhibits high activity and excellent enantioselectivity (ee over 90.2%), which is comparable to that of the best commercial Pt/Al2O3 catalysts. The high catalytic performance is attributed not only to the developed cubic channel structure of the Pt catalyst support, but also to the enhancement of the interaction of Pt nanoparticles and the Al2O3-grafted support, which would improve the modification of cinchonidine on the surface of Pt particles. These indicate that the Al2O3 modified cubic mesoporous silica is a novel, promising support material for the heterogeneous chiral catalysis.

Key words: mesoporous matrix, platinum catalyst, cinchonidine, chiral modification, ethyl 2-oxo-4-phenyl-butyrate, ethyl pyruvate, enantioselective hydrogenation