Densities, Viscosities and Excess Properties of Binary Mixtures of 1,1,3,3-Tetramethylguanidinium Lactate + Water at T = (303.15 to 328.15) K

Densities and viscosities of 1,1,3,3-tetramethylguanidium lactate ([TMG]L) (1) + H2O (2) with different compositions were determined at temperatures from (303.15 to 328.15) K. Densities of [TMG]L (1) + H2O (2) decrease with the increase of temperature. However, when the mole fraction of water is lower than 0.5, the water content does not have an obvious influence on the density of [TMG]L. When the mole fraction of water is greater than 0.5, the densities of [TMG]L (1) + H2O (2) decrease obviously with further increasing the mole fraction of water. Viscosity of [TMG]L decrease dramatically with the increase of temperature and the water content. Excess molar volumes (VE) and viscosity deviations (Δη) of the binary mixtures were calculated by the experimental data and fitted to the Redlich–Kister equation with four parameters. The result shows that the values of VE and Δη for the binary mixtures are negative over the whole composition range and temperatures from (303.15 to 328.15) K. The negative of the excess properties indicates a strong interaction between the ionic liquid and water. The partial molar volumes (V̅i), excess partial molar volumes (V̅iE), Gibbs energy of activation for viscous flow (ΔG*), and excess Gibbs energy of activation for viscous flow (ΔG*E) of the binary mixtures were also calculated based on the densities and viscosities data. Besides, the Jouyban–Acree model was used to correlate the densities and viscosities of the binary mixtures with respect to the mixture composition and temperature simultaneously.