Densities of a deep eutectic solvent based on choline chloride and glycerol and its aqueous mixtures at elevated pressures

Deep eutectic solvents are cheap and biodegradable alternatives to conventional ionic liquids and volatile organic solvents. In this work, we present new measurements on the densities of the deep eutectic solvent choline chloride:glycerol (GLY) and its aqueous mixtures in the temperature range (298.15–323.15) K and pressures up to 50 MPa. The density was measured using a vibrating-tube density meter and the experimental uncertainty was estimated to be ±0.1%. Density data were used to derive other properties such as isothermal compressibility, isobaric expansivity, and excess molar volume. The excess molar volumes of the mixtures of GLY (1) + H2O (2) were investigated and an empirical equation was used to represent their dependence on temperature, pressure, and composition. The density data at elevated pressures were correlated with the temperature, pressure, and composition by a Tait-type equation.