Liquid-liquid phase equilibrium and interaction exploration for separation of azeotrope (2,2,3,3-tetrafluoro-1-propanol + water) with two imidazolium-based ionic liquids

Abstract

For separating azeotropic mixture 2,2,3,3-tetrafluoro-1-propanol (TFP) and water, two kinds of imidazolium-based ionic liquids 1-hexyl-3-methylimidazolium trifluoromethanesulfonate ([HMIM][OTf]) and 1-octyl-3-methylimidazolium trifluoromethanesulfonate ([OMIM][OTf]) were adopted to separate TFP and water. The liquid-liquid equilibrium behavior for the mixtures (water + TFP + [HMIM][OTf]) and (water + TFP + [OMIM][OTf]) were measured at temperature of 298.15 K and pressure of 101.3 kPa. The extraction ability of [HMIM][OTf] and [OMIM][OTf] was explored with partition ratio and selectivity. In the meantime, the hydrogen bond lengths, total electron density, interaction energies and deformation electron density were calculated to analyze the interactions between the [HMIM][OTf]/[OMIM][OTf] and (TFP/water). Also, the liquid-liquid equilibrium data was fitted by the NRTL model.