Ultrasonic-assisted synthesis of the ionic liquid [EMIm]BF_4 by one-step and application to esterification reaction

Firstly,the N-methylimidazole was synthesized in this paper.Then 1-ethyl-3-methyl imidazole terafluoroborate {[EMIm]BF4} was synthesized by one step.The structure was characterized by FT-IR and was consistent with the literature.The experimental results showed that the optimum synthesis condition of the ionic liquid by one-step was under 70 ℃ for 3 h.[EMIm]BF4 was applied as solvent and catalysis for ethyl acetate reaction,the yield was 71.2%,remarkably higher than yield under the H2SO4 catalysis.In addition,the products were easily separated and the ionic liquids can be reused in the reaction.