Three imidazolium-based ionic liquids: 1-methy-3-methylimidazolium dimethylphosphate ([MMIM][DMP]),1-ethyl-3-methylimidazolium diethylphosphate ([EMIM][DEP]) and 1-butyl-3-methylimidazolium dibutylphosphate ([BMIM][DBP]) were used as entrainers to separate acetonitrile + ethanol mixtures. Isobaric vapor-liquid equilibrium (VLE) data were measured at 101.3 kPa. Addition of ionic liquids (ILs) produced a crossover effect on the VLE of the acetonitrile + ethanol system and the azeotropic phenomenon of acetonitrile and ethanol could be eliminated as the mole fraction of ionic liquids reaches a certain value. The separation performance of the three ILs follows the order of [BMIM][DBP] > [EMIM][DEP] > [MMIM][DMP]. Finally, the experimental VLE data were well fitted with the nonrandom two-liquid (NRTL) model. (C) 2018 Elsevier B.V. All rights reserved.