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将合成的N-取代的吡啶-2-醛亚胺制备成2∶1型不对称吡啶亚胺钴(Ⅱ)配合物(CoL2n,n=1,2…6),并通过红外光谱、元素分析、核磁共振氢谱、热重分析等对相关化合物进行表征。以分子氧为氧源,考察催化剂的种类、溶剂、反应温度、反应时间对苯乙烯环氧化反应性能的影响。研究表明,配合物CoL42是最有效的催化剂;配合物中亚氨氮上取代基的供电子性和空间位阻有利于提高配合物的催化活性;在优化的反应条件下,苯乙烯的转化率达99.9%,环氧苯乙烷的选择性为62.4%。
The synthesized N-substituted pyridin-2-aldimines were prepared into 2: 1 asymmetric cobalt (II) complexes of pyridine imine (CoL2n, n = 1, 2 ... 6) and characterized by FTIR, elemental analysis , 1H NMR, TGA and other related compounds were characterized. Using molecular oxygen as oxygen source, the influence of catalyst type, solvent, reaction temperature and reaction time on the epoxidation of styrene was investigated. The results showed that the complex CoL42 was the most effective catalyst. The electron donating and steric hindrance of the substituents on the iminium nitrogen in the complex could improve the catalytic activity of the complex. Under the optimized reaction conditions, the conversion of styrene reached 99.9%, the selectivity to styrene oxide is 62.4%.