Separation of isopropanol from its aqueous solution with deep eutectic solvents: liquid–liquid equilibrium measurement and thermodynamic modeling

In this work, to separate the azeotrope of isopropanol and water using liquid–liquid extraction, two deep eutectic solvents (DESs) were prepared with methyl trioctyl ammonium chloride and (1-hexanol/1-decanol), which were characterized by ¹H NMR and were adopted as extractants. The liquid-liquid equilibrium data for the mixtures (DESs + isopropanol + water) were determined at 298.15 K and 308.15 K. The distribution ratio (D) and separation factor (S) were obtained to judge the extraction performance for the selected DESs. The calculated values of D and S showed that the separation of the mixture isopropanol and water by the DESs is feasible. In addition, the experimental data were successfully fitted by the NRTL model with the RMSD values less than 0.0080. The parameters of the NRTL model were optimized, which is helpful for the separation design and simulation. (author)