Physicochemical Properties and Related Property Prediction of New Amide-Based Deep Eutectic Solvents in the Water/Acetonitrile System

Three kinds of amide-based deep eutectic solvents (DESs) were prepared with formamide, acetamide, and propionamide as hydrogen bond donors and caprolactam as the hydrogen bond acceptor. The density, viscosity, and surface tension of the mixtures of DESs and water/acetonitrile were measured at whole molar concentrations within the temperatures from 288.15 to 318.15 K. Subsequently, the corresponding volume properties, viscous flow properties, and surface properties were calculated. The excess viscous flow activation Gibbs free energy and the excess surface Gibbs free energy are combined with the Redlich–Kister empirical equation for viscosity and surface tension prediction. The linear fitting of the predicted values and experimental values shows that the fitting slope is close to 1 and the r² is close to 0.999, fully indicating that the two prediction models have extremely excellent prediction effects on viscosity values and surface tension values.