Preparation And Applications Of Novel Aza-Crown Ether Complex Cation Ionic Liquids

Ionic liquids, as one of green non-conventional media and functional materials, have gone through great developments in past two decades. Due to their particular properties such as lower vapour pressure, remarkable solubility behavior, ease of reuse, and excellent thermal and chemical stability, they can be used as ideal substitution to replace traditional volatilizes. Addtionally, both organic compounds and inorganic compounds can be dissolved readily in ILs, which enable them been applied successfully in a variety of reactions as environmentally benign solvents and catalysts. Based on the fundamental knowledge and previous work, a series of ionic liquids consisting of an aza-crown ether chelated alkali metal cation and various anions, were designed and synthesized. All these aza-crown ether complex cation ionic liquids (aCECILs) have melting point below room temperature.This article mainly introduces the synthesis of novel aza-crown ether complex cation ionic liquids, and their application in various organic reactions as catalysts.Chapter1:An overview of the definition, type, properties and synthsis strategies of the ionic liquids, and their applications in organic reactions and other areas.Chapter2:The synthesis protocol of aza-crown ether, which can effectively chelated alkali metal ions as cations of our new ionic liquids. In addition, we successfully introduce analkanesulfonic acid into the aza-crown ethers, to generate five novel functional acidic ionic liquids. Furthermore, these ionic liquids were characterised by NMR and FTIR spectroscopy, thermogravimetric differential thermalanalysis (TG-DTA) and elemental analysis.Chapter3:The aCECILs1-aza-[18-C-6KH][HSO4]2have been applied in esterification and synthesis of bis-indolylmethanes as catalysts. We successfully utilized the aCECIL containing [HSO4] as anion to catalyze esterification with five alcohols and acetic acid, which achieved excellent yields. Meanwhile, they have been used in condensation reaction between indole and aldehyde as effective catalysts, to generate bis-indolylmethanes derivatives. This reaction can afford92%yield at30℃in1hour.Chapter4:The Biginelli reaction of benzaldehyde, ethyl acetoacetate, and urea in ethanol was investigated in the presence of functionalized aza-crown ether cation ILs. As an efficient and recyclable IL catalyst,1-butyl-1-aza-[18-C-6KSO3H][BF4]2can achieved the best result (92%) and stay its activity after five cycles. After screening the reaction conditions, a variety of substituted aldehydes were investigated under the optimal condition.Chapter5:Functionalized aza-crown ether cation ILs was applied to Mannich reaction and synthsis of biscoumarin derivatives. In Mannich reaction,1-butyl-1-aza-[18-C-6KSO3H][TFA]2/C2H5OH was found to be the most effective catalyst system afforded the highest yield (83%) in room temperature after6h. In addition,1-butyl-l-aza-[18-C-6KSO3H][TFA]2showed high activity in synthsis of biscoumarin derivatives, this reaction can achieve98%yield in the mixed solvent of water-alcohol (1:1, v/v) for30min.