Density, Viscosity, and Electrical Conductivity of (Choline Chloride + Ethylene Glycol) Mixtures Covering Concentrations from Neat Molecular Solvent to Supersaturated Solutions

This contribution provides data for density, ρ, viscosity, η, and electrical conductivity, κ, of [choline chloride (ChCl, component 1) + ethylene glycol (EG, 2)] mixtures. ChCl concentrations from neat EG to x 1 = 0.333 (ChCl:2EG) were covered for ρ and η. For κ, additionally, x 1 = 0.352 was studied. Temperature ranges covered are T = 278.15–363.15 K for ρ and η, and T = 278.15–338.15 K for κ. The observed temperature dependence at a given x 1 could be empirically described by a quadratic function for ρ and the Vogel–Fulcher–Tammann equation for η and κ. Properties obtained for ChCl:2EG were compared to the data published so far. It turned out that sample purity, including moderate water content, does not greatly influence ChCl:2EG density. However, η( T ) decreases substantially with rising water content. With some exceptions, most of the published η( T ) and κ( T ) data strongly disagree with the present fits. The properties derived from the measured data allowed some conclusions on interspecies interactions: apparent molar volumes obtained for the solute suggest its structure-breaking effect on the inherent EG structure, with solute–solute contacts playing the dominant role here. Despite the rather high conductivity, {ChCl + EG} mixtures show low ionicity, indicating pronounced ChCl self-aggregation.