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综述了不同结构离子液体对Diels-Alder反应的影响,总结了大量国内外有关离子液体中Diels-Alder反应.分别从极性、酸性和黏度的角度分析了离子液体结构变化对Diels-Alder反应产物选择性或反应速率的影响.讨论了离子液体中所能形成的氢键种类、咪唑类阳离子C(2)位取代情况、离子液体的Lewis酸性或Br?nsted酸性、离子液体黏度和反应体系黏度等因素的影响.采用量子化学密度泛函理论计算了反应活化能、反应物的亲电性和过渡态C?C键长.结果表明,离子液体的独特结构能降低反应活化能,同时增加反应过程中成键的不协同性.指出未来的发展方向是通过对离子液体物理性质更深入的研究,基于反应机理合成功能化离子液体,进一步优化反应,发展新型、高效、绿色的Diels-Alder反应,从而扩大其应用.
The effects of different ionic liquids on Diels-Alder reaction were summarized, and a large number of Diels-Alder reactions in ionic liquids were summarized. The changes of Diels-Alder reaction products were analyzed from the aspects of polarity, acidity and viscosity respectively. Selectivity, or reaction rate.The types of hydrogen bonds that can be formed in the ionic liquid, the C (2) substitution of the imidazolium cation, the Lewis acidity or the Brønsted acidity of the ionic liquid, the viscosity of the ionic liquid and the viscosity of the reaction system Etc. The reaction activation energy, the electrophilicity of the reactants and the C? C bond length of the transition state have been calculated by using the quantum chemical density functional theory.The results show that the unique structure of the ionic liquid can reduce the activation energy and increase the reaction time It is pointed out that the future direction of development is to further develop the new, efficient and green Diels-Alder reaction by further studying the physical properties of ionic liquids, synthesizing functionalized ionic liquids based on the reaction mechanism, and further optimizing the reaction , Thus expanding its application.