Nitration Of Aromatic Compounds Catalyzed By Metal Bis[(Perfluoroalkyl)Sulfonyl]Imides In Quaternary Ammonium Based Ionic Liquids

Nitration of aromatic compounds is one of the 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 recent 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((perfluoroalkyl)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 nitration 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)sulfonyl)imides.The five quaternary ammonium ionic liquids named tributylammonium bis((trifluoromethyl)sulfonyl)imide ([NH₄₄₄][NTf₂]),trihexylammonium bis((trifluoromethyl)sulfonyl)imide([NH₆₆₆][NTf₂]), triethyl-n-heptylammonium bis((trifluoromethyl)sulfonyl)imide([N₂₂₂₇][NTf₂]),tributyln -hexylammonium bis((trifluoromethyl)sulfonyl)imide([N₄₄₄₆][NTf₂]) and tetrahexylammonium bis((trifluoromethyl)sulfonyl)imide([N₆₆₆₆][NTf₂]).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 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 influence of the ionic liquids,catalysts and reaction temperature et al on the aromatic nitration was investigated.The results indicated that the nitration reacted in ionic liquids was appreciably affected by the structure of ionic liquids. The ionic liquids 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 iodobenzene.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 liquids 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 geometry conformations indicated that there were some special associations between the structure of ionic liquids and their nature.In summary,the metal bis((perfluoroalkyl)sulfonyl)imides/ionic liquids behaved highly effective,environmentally friendly,and easy recycled for catalyzed aromatic nitration and could provide some enlightenment for the development of clean nitration. Their further potential application in organic synthesis can be optimistically expected.The quantum chemistry calculation of the ionic liquids and the polarity could provid several academically and experimentially supporting for the molecular designing of the ionic liquids.