Densities, Viscosities, and Excess/Deviation Properties of the Ternary System 2-(Methylamino)ethanol + Dimethyl Sulfoxide + Water and the Binary Subsystems

Abstract

Densities and viscosities of the ternary system 2-(methylamino)ethanol (MAE) + DMSO + water and its corresponding binary constituents have been measured experimentally over the whole composition range and the temperature range from 293 to 353 K. The excess molar volumes (VE), viscosity deviations (Δη), and excess free energies of activation (ΔG*E) of the binary systems were correlated with the Redlich–Kister equation, while the experimental data of ternary mixtures were represented by using Nagata–Tamura, Cibulka, Singh, and Redlich–Kister equations. For binary mixtures, the VE values of aqueous DMSO and aqueous MAE are negative but positive for the nonaqueous blend of MAE + DMSO. The values of Δη and ΔG*E of aqueous binary systems are positive and negative, respectively, for the binary mixture of MAE + DMSO over the whole composition range and at all temperatures. These behaviors can be interpreted with molecular interactions and structural effects. The V123E and Δη123 values have also been derived from the experimental data of the ternary system. It was found that the V123E values are negative except for the regions highly deficient in water. The values of Δη123 become more positive in both H2O- and MAE-rich regions that were highly poor in DMSO. The observed behaviors indicate that the properties of the ternary system investigated are dominated by binary effects.