埃洛石表面修饰并负载salen钼高效催化烯烃环氧化反应

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。

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

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 photoelec‐tron 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 epoxi‐dation 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 con‐trast experiments, it was determined that the salen structure played an important role in immobi‐lizing 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 cata‐lyzed by the catalyst were determined. The catalyst could be reused several times without signifi‐cant loss of catalytic activity. Given that halloysite nanotubes are cheap and easy to obtain, this cat‐alyst offers a novel alternative for the rational design of catalysts with desired features.