Effect of bis(trifluoromethylsulfonyl)imide-based ionic liquids on the isobaric vapor - liquid equilibrium behavior of ethanol + dimethyl carbonate at 101.3 kPa

Isobaric vapor - liquid equilibrium (VLE) data for the binary system of ethanol + dimethyl carbonate (DMC) and the ternary systems of ethanol + DMC + 1-hexyl-3-methylimidazolium bis[(trifluoromethyl) sulfonyl] imide ([HMIM][NTf2]) and ethanol + DMC + 1-butyl-3-methylimidazolium bis[(trifluoromethyl) sulfonyl] imide ([BMIM][NTf2]) were obtained by using a modified Othmer still at a constant pressure of 101.3 kPa. The experimental results indicated that both [HMIM][NTf2] and [BMIM][NTf2] had a notable effect on the azeotropic system of ethanol - DMC. The NRTL model was used in this work to correlate VLE data and the calculated data agreed well with the experimental value. The minimum mole fractions of [HMIM][NTf2] and [BMIM][NTf2] needed to eliminate azeotrope were 0.125 and 0.170 calculated by NRTL model, respectively. And the [HMIM][NTf2] was found to be a better candidate of entrainer for separating the ethanol - DMC azeotrope.