Study On The Synthesis Of Ionic Liquids

Ionic liquid is also known as room temperature molten salt , which is composed of organic positive ions and inorganic negative ions . Because it has the unique properties including low melting point, lack of measurable vapor pressure, wide electrochemical window, adjustable acidity, amenable to diverse solutes, proper viscosity and density, ionic liquid has been widely used in many fields such as electrochemistry, organic synthesis, catalyst and separation. And it arouses great interest in industry for it does not pollute the environment. In this thesis three kinds of ionic liquid are synthesized and investigated including N-methyl-N'-ethylimidaz-olium fluoborate([emim]BF4), N-ethylpyridium fluoborate([epy]BF4) and N-butylp-yridium fluoborate([bpy]BF4). First bromoethane reacted with pyridine and we got N-ethylpyridinium bromide ([epy]Br) as the intermediate of ionic liquid. During the preparing process in order to determine optimal reaction parameters , different reaction temperatures, reactant ratio and three types of solvent were used.. Then [epy]Br was mixed with silver fluoborate(AgBF4) in methanol and replacement reaction took place. And by the same means [bpy]BF4 was manufactured. While [emim]BF4 was prepared , firstly N-methylimidazole was synthesized using glyoxal,methanal, methylamine, aqueous amine as raw materials according to one step ring sum way.Secondly N-methylimidazole reacted with bromoethane and [emim]Br was gotten. Then anions exchange reaction took place between [emim]Br and AgBF4 and we got the final product [emim]BF4. Using IR ,1H-NMR the structures of these three kinds of ionic liquids were researched and the results were satisfying.