Synthesis of Imidolium-based and Pyridinium-based Ionic Liquids under Ultrasonic Irradiation

Used N-methylimidazole,pyridine and bromoalkanes as raw materials,four types of ionic liquids 1-ethyl-3-methylimidazolium bromide salt Br,1-butyl-3-methylimidazolium bromide salt Br,N-ethylpyridine bromide saltBr and N-butylpyridine bromide salt(Br) were synthesized without solvent under the conditions of ultrasound intermittent operation.Their melting points were measured at room temperature.Results showed the bigger of the size of organic cation in ionic liquids with the same anion the smaller of melting point of the ionic liquids Compared with conventional synthesis,the reaction time was drastically reduced and a higher yield was obtained.Then the Br as an intermediate,a hydrophilic ionic liquid BF4 and hydrophobic ionic liquid PF6 were prepared through anion-exchange.Their viscosity was determined at 25 ℃.The six ionic liquids synthesized were characterized by 1H NMR,13C NMR and IR spectra.