芳香族烯烃的Wacker氧化反应研究

发布时间：2018-06-21 04:19

本文选题：Wacker氧化 + 过氧化氢　；参考：《南京理工大学》2017年硕士论文

【摘要】：Wacker氧化是一种由烯烃直接合成羰基化合物的重要方法,最早被应用于乙烯工业制备乙醛,传统Wacker氧化方法使用钯盐催化剂和氯化亚酮氧化剂在空气下反应。随着环境经济的发展,传统的Wacker氧化反应显现出越来越多的局限性,如金属铜离子污染、含氯副产物的生成、底物普适性差、烯烃异构化和催化剂难以回收等缺陷。因此,研究探索和建立新方法以实现反应可持续性发展,具有重要实际意义。双氧水作为一种绿色氧化剂已被应用于芳香族烯烃的Wacker氧化反应,但目前相关报道所用钯催化剂较为复杂。因此,我们尝试使用简单无配体的二价钯催化剂催化双氧水实现芳香族烯烃的Wacker氧化。研究发现,以醋酸钯为催化剂,在酸性条件下,应用乙腈为反应介质,双氧水溶液为氧化剂,芳香族烯烃能在温和条件下,高选择性和高产率地转化为相应的甲基酮化合物,呈现出较好的底物普适性。研究发现不同芳烯烃的反应活性不同,空间效应与双键上的电子云密度直接影响Wacker氧化反应过程。进一步研究发现,以零价钯为催化剂,双氧水作为氧化剂,在最佳反应条件下,芳香族烯烃转化为芳香族甲基酮的产率高达93%,所用催化剂重复使用五次后,仍能保持较好的催化活性。研究探讨了新方法可能的催化反应机理,为发展Wacker氧化反应提供了一个新的选择。
[Abstract]:Wacker oxidation is an important method for the direct synthesis of carbonyl compounds from olefin. It was first used in ethylene industry to produce acetaldehyde. Traditional Wacker oxidation method uses palladium salt catalyst and ketone chloride oxidant to react in air. With the development of environment and economy, the traditional Wacker oxidation reaction shows more and more limitations, such as metal copper ion pollution, the formation of chlorinated by-products, the poor substrate universality, isomerization of olefins and the difficulty of catalyst recovery and so on. Therefore, it is of great practical significance to explore and establish new methods to realize the sustainable development of response. As a green oxidant, hydrogen peroxide has been used in the Wacker oxidation of aromatic olefin. Therefore, we try to realize the Wacker oxidation of aromatic olefin using simple ligand-free palladium catalyst to catalyze hydrogen peroxide. It was found that under mild conditions, using palladium acetate as catalyst, acetonitrile as reaction medium and hydrogen peroxide solution as oxidant, aromatic olefins could be converted into corresponding methyl ketones with high selectivity and high yield. It presents better substrate universality. It was found that the reaction activity of different alkenes was different, and the space effect and the electron cloud density on the double bond directly affected the oxidation process of Wacker. It was further found that under the optimum reaction conditions, the conversion of aromatic olefin to aromatic methyl ketone was as high as 933%, and the catalyst was reused for five times, using zero valent palladium as catalyst and hydrogen peroxide as oxidant, and under the optimum reaction conditions, the yield of aromatic olefin to aromatic methyl ketone was as high as 933%. It can still maintain good catalytic activity. The possible catalytic reaction mechanism of the new method is discussed, which provides a new choice for the development of Wacker oxidation reaction.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O621.25

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