Separation of azeotrope 2,2,3,3-tetrafluoro-1-propanol and water by extractive distillation using ionic liquids: Vapor-liquid equilibrium measurements and interaction analysis

Abstract

To separate the azeotrope 2,2,3,3-tetrafluoro-1-propanol (TFP) and water, the extractive distillation was applied using ionic liquids. In this work, two ionic liquids, [EMIM][Ac] and [EMIM][Cl], were selected as the entrainers screened by the COSMO-SAC model. For purpose of validating the separation effect of these two ionic liquids, the isobaric vapor-liquid equilibrium (VLE) data for the mixtures (water + TFP + [EMIM][Ac] / [EMIM][Cl]) were determined at 101.3 kPa with a modified Rose-type recirculating still. By adding certain amount of entrainers, the relative volatility increased significantly. Afterwards, the NRTL model was adopted to correlate the measured experimental data. Moreover, the surface-charge density distribution (σ-profile) and the interaction energy for the above systems were calculated and explored, which can provide the theoretical insight into the separation of the azeotrope by ionic liquids.