High-pressure volumetric properties of choline chloride–ethylene glycol based deep eutectic solvent and its mixtures with water

The densities of the deep eutectic solvent (DES) based on choline chloride and ethylene glycol (Ethaline) and its mixtures with water were measured from 298.15 K to 323.15 K over an extended pressure range (0.1–50) MPa. Other important properties such as isothermal compressibility and isobaric expansivity were derived for the pure system using the experimental data. The high-pressure densities were accurately correlated to the temperature, pressure and composition using a Tait-type equation. For the binary mixtures of Ethaline (1) + H2O (2), the excess molar volumes were investigated and represented as a function of temperature and composition by a Redlich–Kister-type equation. Results indicated that the correlations proposed in this work can be used to accurately predict the densities of the studied systems as functions of temperature, pressure and composition.