Preparation, Characterization Of Novel Ionic Liquids And Their Application In Catalytic Synthesis

Due to their wide liquid range, nonvolatility, adjustability of chemical and physical properties and large windows of electrochemistry, ionic liquids are becoming ever-expanding applications as alternative reaction media and catalysts for organic synthesis, solvents and extractants for separation and electrolytes for electrochemistry. In search for an environmentally benign chemistry, more and more novel ionic liquids are widely investigated to expand the utility of ionic liquids and open up a new field of ionic liquid chemistry. The most recent publications in this area focus on the synthesis of new ionic liquids, systematic investigations of their properties and further applications, It is very important to accumulate a substantial body of scientific and technological data for these fascinating fluid materials as solvents and catalysts in chemical synthesis and separation processes can be realized. This dissertation focuses on (1) synthesis of twelve melting salts based on N-alkylationbenzimidazolium ; (2) synthesis of 1,4-dioxane by dehydration of diethylene glycol (DEG); (3) preparation a binary ionic liquid system LiCl-Urea, low eutectic system. The details are given as follows:Part one Twelve melting salts based on N-alkylationbenzimidazolium have beenprepared, they are :1 -Ethyl-3-butyl-benzimidazoliumbromine (C₄eBimBr)1 -Ethyl-3-butyl-benzimidazoliumtetrafluoroborate (C₄eBimBF₄)1 -Ethyl-3 -butyl-benzimidazoliumhexafluorophosphate(C₄eBimPF6)1 -Ethyl-3 -amyl-benzimidazoliumbromine(C₅eBimBr)1 -Ethyl-3 -amyl-benzimidazoliumtetrafluoroborate (C₅eBimBF₄)1 -Ethyl-3 -amyl-benzimidazoliumhexafluorophosphate (C₅eBimPF₆)l-Ethyl-3-(2-hydroxyethyl)-benzimidazoliumchlorinate(C₂OeBimCl),l-Ethyl-3-(2-hydroxyethyl)-benzimidazoliu-mtetrafluoroborate(C₂OeBimBF₄),l-Ethyl-3-(2-hydroxyethyl)-benzimidazoliumhexa-fluorophosphates(C₂OeBimPF₆),1-Ethyl-3-(2-carboxylethyl)-benzimidazoliumchlorin-ate(C₂O₂eBimCl),l-Ethyl-3-(2-carboxylethyl)-benzimidazoliumtetrafluoroborate(C₂O₂eBimBF₄), l-Ethyl-3-(2-carboxylethyl)-benzimidazoliumhexafluorophosphate(C₂O₂eBimPF₆); They are characterized by FT-IR, 'HNMR, element analysis(EA) to make certaintheir molecular formula. At the same time, the melting points of them and their other physical properties, such as conductivity, viscosity, solubility, and thermo stability were determined; phase behavior of C₅eBimBr characterized by DSC; some electrochemical potential windows were also determined by means of the cyclic valtommetry of ones of compounds.C₄eBimBr integrating with anhydrous AlCl₃ showed excellent catalytic activity in the reactions of benzene alkylation with 1-dodecene, when the mole ratio of C₄eBimBr:AlCl₃ was 1:2. the reaction carried at atmospheric pressure, the 1-dodecene was totally converted in the reaction of benzene alkylation in 5 minutes at room temperature, e; the selectivity in the aklylation reaction increase 4⁵% (2-LAB + 3-LAB isomers). Furthermore, the catalyst was utilized repeatedly over five times with the conversion and selectivity nearly unchanged.Part two 1,4-dioxane is a excellent solvent, it could be application in degreasing,electronics, metal finishing, fabric cleaning, Pharmaceuticals, herbicides and pesticides, antifreeze, paper manufacturing and many other applications. In this work,ionic liquid [Hmim]BF4 was used as catalyst and solvent in the synthesis of 1,4-dioxane by dehydration of diethylene glycol (DEG). The results display that ionic liquid Hmim]BF4 has a higher catalytic activity, Under the optimum conditions (a molar ratio of 1:1 of substrate to ionic liquid), the conversion and selectivity can reach 95.57% and 71.23%, respectively. Furthermore, ionic liquid could be recyclable use. It in certain overcomes the major disadvantage of solid acid catalysts, hard reaction conditions, short time life et al.Part three low eutectic system LiCl-Urea is prepared, which is a binary ionic liquid system. The electrochemical potential windows were determined by means of the cyclic valtommetry. Its conductivity is measured by DDS-11 conductance...