Synthesis of ethyl acetate using acid ionic liquid [Hmim]H_2PO_4 as catalyst

Ethyl acetate was synthesized with acetic acid and ethanol using ionic liquid [Hmim]H_2PO_4 as catalyst.Influencing factors of esterification reaction were investigated.Ionic liquid was recovered by solvent extraction and suitable solvent was chosen.And the chemical structure of [Hmim]H_2PO_4 was analyzed by FT-IR.The results showed that conversion rate of ethanol of 90.18 % was obtained with the optimum conditions that the molar ratio of acetic acid-to-ethanol-to-the ionic liquid was 1.2∶1∶0.15 and reaction time was 4 h.The catalyst can be repeatedly used for 5 times with the conversion of ethanol of over 88.00 wt.%.Cyclohexanone-oxime was chosen as extraction solvent to recovery the ionic liquid and remove water.It was favorable for ethyl acetate,acetic acid and ethanol separated by rectification.