Separation of azeotropic mixture (2, 2, 3, 3-Tetrafluoro-1-propanol + water) by extractive distillation: Entrainers selection and vapour-liquid equilibrium measurements

Abstract For separating the azeotrope of 2, 2, 3, 3-tetrafluoro-1-propanol (TFP) and water by extractive distillation, N -methyl pyrrolidone (NMP), N -methyl formamide (NMF) and N , N -dimethyl formamide (DMF) were selected as entrainers using the COSMO-SAC model based on solvent capacity. And the charge density surface of entrainers and each component in the azeotrope system were calculated. The vapour-liquid equilibrium (VLE) data for the mixtures (TFP +NMP), (TFP + NMF) and (TFP + DMF) were measured by a modified Rose-type recirculating still at the pressure 101.3 kPa. The thermodynamic consistency for the VLE data was validated using the Herington and van Ness methods. The VLE data were correlated with NRTL, Wilson and UNIQUAC models, and the interaction parameters of thermodynamic models were fitted. Meanwhile, the effect of the entrainers on the VLE for TFP and water was explored. Compared with NMF and DMF, NMP was adopted as the suitable entrainer for separation of the azeotropic mixture TFP and water by extractive distillation.