Diffusivity, Density and Viscosity of Aqueous Solutions of Choline Chloride/Ethylene Glycol and Choline Chloride/Malonic Acid

The diffusion coefficients of aqueous mixtures of two deep eutectic solvents (DESs) and their densities and viscosities have been measured at different concentrations and temperatures (303.15 to 323.15) K and normal atmospheric pressure. The DESs were choline chloride/ethylene glycol and choline chloride/malonic acid. The diffusion coefficients were measured using Taylor dispersion technique and the data were used to adjust the parameters of such empirical and semi-theoretical models as the equation by Snijder et al., UNIDIF equation, and an equation based on the rough hard-sphere theory. The density and viscosity of the aqueous DES systems have also been measured and the data used to determine the parameters of a Vogel-Tamman-Fulcher-type equation, and to express the properties' dependence on temperature and composition. The data and the corresponding values calculated from such equations and correlations agree well.