This paper reports the physicochemical (density, dynamic viscosity, electrical conductivity and refractive index) and the thermodynamic (thermal expansion coefficient, molecular volume, lattice energy and heat capacity) properties of several choline chloride (ChCl) based deep eutectic solvents (DESs), with 1:2 mole ratio, respectively: ChCl:propylene glycol, ChCl:1,3-dimethylurea and ChCl:thiourea, at atmospheric pressure as a function of temperature over the range of 293.15?363.15 K. Their properties were also compared with those of some already characterized ChCl-based DESs, namely ChCl:ethylene glycol, ChCl:glycerol and ChCl:urea (1:2 mole ratio). Density, viscosity and refractive index of all DESs decrease with the increasing temperature while the electrical conductivity increases. Viscosity and conductivity of the tested DESs were fitted by both Arrhenius-type and Vogel?Tamman?Fulcher equations. The changes of molar enthalpy, entropy and Gibbs energy of activation, determined using the Eyring theory, demonstrated the interactional factor as predominant over the structural factor for all DES systems. The fractional Walden rule, used to correlate molar conductivity and viscosity, showed an excellent linear behaviour. It was shown that ChCl:propylene glycol DES had properties similar to ChCl:ethylene glycol and ChCl:glycerol DESs. However, the properties (density, viscosity and electrical conductivity) of ChCl:1,3-dimethylurea and ChCl: :thiourea DESs were inferior to those of the ChCl:urea DES.

Deep eutectic solvents (DESs) are noted to be green ionic liquid (IL) analogues, and their many favourable properties made them interesting for the scientific community. In this study, two novel DESs of citric acid with the monosaccharides D-glucose or D-fructose (1:1 molar ratio) were prepared and characterized. At the atmospheric pressure, the density, the dynamic viscosity, and the electrical conductivity of these eutectic solvents were measured and analysed as the function of temperature in the practical temperature range of 293.15-363.15 K. Arrhenius theory was employed for understanding the transport phenomena in these DESs. By using the experimental data, some important properties were calculated such as molecular volume, lattice energy, heat capacity, molar Gibbs energy, enthalpy and entropy of activation of viscous flow for the synthesized DESs. The fractional Walden rule was employed to establish the relationship between molar conductivity and viscosity, which proved an excellent linear behaviour. Finally, these DESs were tested as cosolvents in oleic acid (OA) ethanolysis. The investigated DESs possess many desirable properties, such as low vapour pressure, inflammability, biodegradability, and can be obtained from available renewable resources. These DESs showed to have the potential to be utilized for several industrial applications, like processing and separation of food constituents, pharmaceutical applications, and mediums for chemical reactions.