催化学报 ›› 2015, Vol. 36 ›› Issue (3): 348-354.DOI: 10.1016/S1872-2067(14)60244-8

• 论文 • 上一篇    下一篇

埃洛石表面修饰并负载salen钼高效催化烯烃环氧化反应

龙雨, 袁冰, 马建泰   

  1. 兰州大学化学化工学院, 功能有机分子化学国家重点实验室, 甘肃兰州730000
  • 收稿日期:2014-09-13 修回日期:2014-11-03 出版日期:2015-02-14 发布日期:2015-02-14
  • 通讯作者: 马建泰

Epoxidation of alkenes efficiently catalyzed by Mo salen supported on surface-modified halloysite nanotubes

Yu Long, Bing Yuan, Jiantai Ma   

  1. State Key Laboratory of Applied Organic Chemistry and College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, Gansu, China
  • Received:2014-09-13 Revised:2014-11-03 Online:2015-02-14 Published:2015-02-14

摘要:

采用温和的化学表面改性和自组装方法成功制备了埃洛石纳米管负载salen钼(HNTs-SL-Mo)催化剂, 运用透射电镜、X射线衍射、红外光谱、诱导偶合等离子体谱和X射线光电子能谱表征了催化剂的形态、大小和分散性等性质.结果证明了salen结构的存在和埃洛石配位钼催化剂的成功制备.制备的催化剂在各种烯烃的环氧化反应中均有很好的活性, 且活性高于均相催化剂.对比实验表明, 在固定MoO(O2)2(DMF)2时, salen结构发挥了重要作用, 不能用N原子作为单一配体来代替.本文还推测了钼和salen配体可能的连接方式和该催化剂催化烯烃环氧化反应的机理.该催化剂在重复使用8次后其活性未见明显下降, 表现出优异的重复使用性能.由于埃洛石是一种廉价易得的材料, 因此它可为设计效果独特的催化剂提供一个选择.

关键词: Salen钼, 烯烃环氧化, 管状埃洛石, 表面修饰, 高效催化剂

Abstract:

Halloysite-nanotube-supported Mo salen (HNTs-Mo-SL) catalysts were successfully prepared using a facile chemical surface modification and self-assembly method. The morphologies, sizes, structure, and dispersion of the as-prepared catalysts were investigated by transmission electron microscopy, X-ray diffraction, and Fourier-transform infrared, inductively coupled plasma, and X-ray photoelectron spectroscopy, which confirmed the existence of the Mo salen structure and successful synthesis of the HNTs-Mo-SL catalyst. The immobilized catalyst was found to be highly reactive in the epoxidation of a wide range of alkenes, including linear, cyclic, and aromatic alkenes. The immobilized catalyst exhibited a higher catalytic activity for alkene epoxidation than homogeneous Mo. In contrast experiments, it was determined that the salen structure played an important role in immobilizing MoO(O2)2(DMF)2 and improving the conversion and efficiency of alkene epoxidation, which could not be obtained using other ligands, such as the N atom as a single ligand. Furthermore, the bonding between Mo and the salen ligands and the possible mechanism of alkene epoxidation catalyzed by the catalyst were determined. The catalyst could be reused several times without significant loss of catalytic activity. Given that halloysite nanotubes are cheap and easy to obtain, this catalyst offers a novel alternative for the rational design of catalysts with desired features.

Key words: Salen molybdenum, Alkene epoxidation, Halloysite nanotube, Surface modification, High-efficiency catalyst