Phase Equilibria and Extraction Properties of Deep Eutectic Solvents in Alcohol–Ester Systems

In recent years, considerable attention has been given to the capability of deep eutectic solvents (DESs) to replace ionic liquids in extraction processes. The objective of this study is to determine the physicochemical parameters of heterogeneous systems and phase equilibria in industrially important mixtures that contain DESs. Ethanol–ethyl acetate–DES, n-propanol–n-propyl acetate–DES, and n-butanol–n-butyl acetate–DES systems have been investigated at a temperature of 293.15 K and atmospheric pressure. DESs based on choline chloride, namely, its mixtures with glycerin and urea, have been studied. An analysis of the capability of DESs to separate the specified mixtures of alcohols and esters has been performed using data on the equilibrium compositions of coexisting liquid phases. The nonrandom two-liquid (NRTL) model has been used to correlate experimental data on liquid–liquid equilibria.