Thermodynamics of Mixtures with Strongly Negative Deviations from Raoult's Law. VII. Excess Molar Volumes at 25 ° C for 1-Alkanol + N -Methylbutylamine Systems—Characterization in Terms of the ERAS Model

Abstract

Excess molar volumes, VEm, at 25°C and atmospheric pressure, over the entire composition range for binary mixtures of methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, and 1-octanol with-methylbutylamine are reported. They are calculated from densities measured with a vibrating-tube densimeter. All the excess volumes are large and negative over the entire composition range. This indicates strong interactions between unlike molecules, which are greatest for the system involving methanol, characterized by the most negative VEm. For the other solutions, VEm at equimolar composition, is approximately the same. The VEm curves vs. mole fraction are nearly symmetrical. The ERAS model is applied to 1-alkanol + N-methylbutylamine, and 1-alkanol + diethylamine systems. The ERAS parameters confirm that the strongest interactions between unlike molecules are encountered in solutions with methanol. The model consistently describes VEm and excess molar enthalpies HEm of the mixtures studied.