The vapor-liquid equilibrium (VLE) data for binary systems of acetone + 1-ethyl-3-methylimidazolebromine ([EMIM][Br]), methanol + 1-ethyl-3-methylimidazolebromine ([EMIM][Br]), acetone + 1-butyl-3-methylimidazolebromine ([BMIM][Br]), methanol + 1-butyl-3-methylimidazolebromine ([BMIM][Br]), and ternary VLE data for systems of acetone + methanol + 1-ethyl-3-methylimidazolebromine ([EMIM][Br]), acetone + methanol + 1-ethyl-3-butylimidazolebromine ([BMIM][Br]) were detected at 101.3 kPa in an all-glass dynamic recirculating still. With the addition of bromine-based ionic liquids, the relative volatility of acetone to methanol was enhanced and the azeotropy was eventually eliminated. As for the separating effect, [EMIM][Br] is better than [BMIM][Br]. The measured binary and ternary VLE data were correlated with the nonrandom two-liquid activity coefficient model, and the results demonstrated that the experimental data and the correlated data were in good agreement.