Liquid–Liquid Equilibrium for Ternary Systems (Ethyl Acetate/Isopropyl Acetate + 2,2-Difluoroethanol + Water) at 298.15 and 308.15 K

Abstract

2,2-Difluoroethanol (DFE) is an important aliphatic fluorine-containing chemical intermediate. During its preparation, an azeotropic mixture of DFE and water is formed. To recover DFE from its aqueous solution, liquid–liquid extraction was applied in this work with isopropyl acetate (IPAc) and ethyl acetate (EtAc) as the extractants. The liquid–liquid equilibrium (LLE) experimental data for these ternary mixtures (EtAc/IPAc + DFE + water) was determined at 298.15 and 308.15 K under 101.3 kPa. To access the extraction performance of extractants EtAc and IPAc, the selectivity (S) and distribution coefficient (D) were calculated from the measured data. The results showed that the S and D values of IPAc were higher than those of EtAc, implying that IPAc is a suitable extractant. The Othmer–Tobias, Bachman, and Hand methods were applied to examine the reliability of the LLE experimental values. The UNIQUAC and NRTL models were adopted to fit the measured LLE data, and the calculated values of the root-mean-square deviation for the two models were less than 0.003.