Liquid-Liquid Equilibria for Separation of Alcohols from Esters Using Deep Eutectic Solvents Based on Choline Chloride: Experimental Study and Thermodynamic Modeling

Deep eutectic solvent (DES) formed by choline chloride and glutaric acid was tested for the separation of azeotropic mixtures of ethanol-ethyl acetate, n-propanol n-propyl acetate, n-butanol-n-butyl acetate, ethanol ethyl propionate, n-propanol n-propyl propionate, and n-butanol-n-butyl propionate. For this aim, the experimental data of liquid-liquid equilibria (LLE) were obtained at a temperature of 313.15 K and atmospheric pressure. Liquid-liquid tie-lines were determined and analyzed. The extraction performance of DES was characterized with distribution coefficients and values of selectivity with respect to alcohol. The NRTL model for LLE data correlation was used. Perturbed-chain statistical associating fluid theory had also been applied for modeling LLE using a "pseudo-component" approach for the DES. Both models were shown to give reasonable estimates for the selectivity values.