The vapor-liquid equilibrium data are measured at 101.3 kPa with a modified Othmer still for three ternary systems: tetrahydrofuran (THF) + ethanol + 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIMI[BF4]), THF + ethanol +1-octy1-3-methylimidazolium tetrafluoroborate ([0MIMI[BF4]), and THF+ ethanol + 1-butyl-3-methylimidazolium dicyanamide([BMIM][DCA]). All the three ionic liquids enhance the relative volatility of THF to ethanol. The experimental data are well fitted with the NRTL model proposed by Renon and Prausnitz. The minimum values of mole fractions calculated by the NRTL model to break the TI-IF + ethanol azetrope are 0.025, 0.073 and 0.132 for [BMIM]IDCAL [BMIM]IBF4] and [OM1M][BF4], respectively. The extractive capacities for separating the THF+ ethanol azeotrope follows the order: [BMIM][DCA] > [BMIM]IBF41> [OMIM][EF41. (C) 2014 Elsevier B.V. All rights reserved.