Effect of ethanol on the density and viscosity of choline chloride/urea eutectic system

The densities and viscosities of choline chloride/urea deep eutectic solvents (DESs) at molar ratios of 1:1.5, 1:2, and 1:2.5 (abbreviated as [ChCl][Urea]1.5, [ChCl][Urea]2 and [ChCl][Urea]2.5) were measured in this work. In addition, the effects of ethanol on the density and viscosity of choline choloride/urea DESs were also investigated. The experimental density and viscosity data were obtained from 303.15 K to 323.15 K at atmospheric pressure. The measurements were carried out using digital vibrating U-tube densimeter and Ubbelohde capillary viscometer. The Jouyban-Acree model was used to correlate the experimental density and viscosity data. In addition, for comparison purpose, the viscosity model based on the preferential solution theory was also used for the viscosity correlation. The excess molar volumes and viscosity deviations of the studied mixtures were calculated from the experimental data, and the results were analyzed. The Redlich-Kister equation was used to correlate the excess molar volumes and viscosity deviations of the ethanol/[ChCl][Urea]x mixtures.