《全氟烷基磺酰亚胺盐在季铵型离子液体中催化芳烃硝化反应(1)》由会员分享,可在线阅读,更多相关《全氟烷基磺酰亚胺盐在季铵型离子液体中催化芳烃硝化反应(1)(135页珍藏版)》请在金锄头文库上搜索。
1、 华 中 科 技 大 学 博 士 学 位 论 文华 中 科 技 大 学 博 士 学 位 论 文 I摘 要 芳香族化合物的亲电硝化反应作为重要的有机反应,多年来一直为人们所关注。随着环保意识的提高和环保立法的强制执行,开发新的高效、环境友好的硝化方法已成为广大化学工作者的研究热点之一。近年来,离子液体作为一种新型的绿色反应介质因其自身优异的理化性质,而被广泛的应用于各类有机化学反应中。离子液体也因此作为溶剂及催化剂被引入到芳烃硝化反应。而将环境友好的高效催化剂全氟烷基磺酰亚胺及其盐类与离子液体结合起来用于催化芳烃硝化反应,对于开发新的绿色硝化方法有着重要的意义。 本论文首先综述了近年来芳烃硝化反
2、应的研究进展,介绍了离子液体的极性以及测量方法,同时简述了离子液体量化计算方面开展的一些工作。 在论文第二章中,合成了五种具有不同阳离子结构的季铵型离子液体以及系列双(全氟烷基磺酰)亚胺盐。五种离子液体分别是:双(三氟甲基磺酰)亚胺三正丁胺盐(简称NH444NTf2) ;双(三氟甲基磺酰)亚胺三正己胺盐(简称NH666NTf2) ;双(三氟甲基磺酰)亚胺三乙基庚胺盐(简称N2227NTf2) ;双(三氟甲基磺酰)亚胺三正丁基己胺盐(简称N4446NTf2) ;双(三氟甲基磺酰)亚胺正四己胺盐 (简称N6666NTf2) 。 通过测定溶剂化显色染料在离子液体中的UV-visible光谱,首次得到
3、了五种离子液体的极性数据,讨论了离子液体结构以及温度对其极性的影响。采用加酸显色的方法对双(三氟甲基磺酰)亚胺镧系金属盐在离子液体中的 Lewis 酸性进行了测定。 在第三、四章中研究了双(全氟烷基磺酰)亚胺盐在离子液体中催化芳烃硝化反应,硝化试剂分别为硝酸酯与浓硝酸。考察了离子液体种类、催化剂及其用量、温度等因素对反应的影响。研究结果表明,离子液体的结构对芳烃硝化反应有明显的影响,离子液体在硝化反应中作为溶剂的同时还表现出一定的催化作用。双(全氟烷基磺酰)亚胺盐/离子液体催化体系对卤代苯硝化反应有很好的催化活性,特别是对碘苯的硝化得到了较好的结果。与有机溶剂相比,离子液体的应用提高了卤代华
4、中 科 技 大 学 博 士 学 位 论 文华 中 科 技 大 学 博 士 学 位 论 文 II苯硝化的对位选择性,且该催化体系容易回收和循环再利用。另外,在论文中探讨了离子液体极性对硝化反应的影响,同时对双(全氟烷基磺酰)亚胺盐/离子液体中进行的芳烃硝化反应的机理进行了讨论。 第五章中,通过在高精度 B3LYP/6-31G*密度泛函水平上的计算,得到了能量稳定的离子液体以及离子液体与硝酸分子相互作用的构型。结合实验数据对离子液体的结构与性能之间的关系;离子液体与甲苯硝酸硝化反应结果进行了研究。并尝试从几何构型、能量差异的角度,对离子液体的微观结构与实验结果和宏观性质之间的内在联系进行了初步探讨
5、。 综上所述,双(全氟烷基磺酰)亚胺盐在离子液体中催化芳烃硝化反应时,表现出高效、环境友好以及容易循环使用等特点,对进一步拓展该类催化剂的应用范围,以及开发高效的绿色硝化方法提供了新的思路。通过对离子液体极性的测定以及对离子液体结构的量化计算,为离子液体的分子设计从理论与实验层面提供了一定的启示与借鉴。 关键词:全氟烷基磺酰亚胺;离子液体;极性;Lewis 酸性;芳烃硝化; 密度泛函; 华 中 科 技 大 学 博 士 学 位 论 文华 中 科 技 大 学 博 士 学 位 论 文 IIIAbstract Nitration of aromatic compounds is one of the
6、most important fundamental organic reactions and has been concerned for years. With the awareness by public and the compulsive implement by legislation for environmental reason, chemists focused their interesting on highly effective and environmentally friendly clean nitration of aromatics. In recen
7、t years, ionic liquids as a new type of green reaction media for its excellent physical and chemical nature have been widely applied to various of organic reaction. Therefore, ionic liquids acted as solvent or catalyst have been utilized for aromatic nitration. For the same reason, metal bis(perfluo
8、roalkyl)sulfonyl)imides as a kind of effective catalyst are employed in ionic liquids not only to afford a new method for aromatic nitration but also indicate important significane for the development of clean nitration. In chapter 1, we have firstly reviewed the research evolution of aromatic nitra
9、tion and described the polarity of ionic liquids as well as the measurement method. Meanwhile, the quantum chemistry calculation of ionic liquids was introduced. In chapter 2, at first we synthesized five different quaternary ammonium based ionic liquids as well as series of metal bis(perfluoroalkyl
10、)sulfonyl)imides. The five quaternary ammonium ionic liquids named tributylammonium bis(trifluoromethyl)sulfonyl)imide (NH444NTf2), trihexylammonium bis(trifluoromethyl)sulfonyl)imide (NH666NTf2), triethyl-n-heptylammonium bis(trifluoromethyl)sulfonyl)imide (N2227NTf2), tributyl- n-hexylammonium bis
11、(trifluoromethyl)sulfonyl)imide (N4446NTf2) and tetrahexyl- ammonium bis(trifluoromethyl)sulfonyl)imide (N6666NTf2). The polarity of the ionic liquids was determined by meaning the UV-visible spectra of the solvatochromic dyes which dissolved in ionic liquids. The Lewis acidity of Ln(NTf2)3 in ionic
12、 liquids was characterized by halochromism of 2,4, 4 6-tetramethoxyazobenzene. Nitration of aromatic compounds catalyzed by metal bis(perfluoroalkyl)sulfonyl)- imides in ionic liquids were discussed in chapter 3 and 4, with acetyl nitrate and nitric acid as nitrating agents, respectively. The influe
13、nce of the ionic liquids, catalysts and reaction temperature et al on the aromatic nitration was investigated. The results indicated that the 华 中 科 技 大 学 博 士 学 位 论 文华 中 科 技 大 学 博 士 学 位 论 文 IVnitration reacted in ionic liquids was appreciably affected by the structure of ionic liquids. The ionic liqu
14、ids were not only acted as solvent for nitration but also behaved as catalyst. Nitration of substituted aromatics in metal bis(perfluoroalkyl)sulfonyl)imides/ionic liquids systems demonstrated that the catalyst systems behaved very good catalytic activity on the halobenzene, especially for iodobenze
15、ne. Compared with the organic solvent, the utilization of ionic liquids improved regio-selectivity for nitration of halobenzenes, and the catalyst systems easy to recycle. In addition, the influence of polarity of ionic liquids to the nitration and the mechanism of aromatic nitration in ionic liquid
16、s were discussed. In chapter 5, the stable conformations of the ionic liquids and the nitric acid together with ionic liquids were obtained after geometry optimization at B3LYP/6-31G* level. The relationships of the structure of ionic liquids between its properties as well as the influence of the ionic liquids on nitration of toluene were discussed though experimental data contrast with computation results. The discrepance of energy and geo