EXCESS GIBBS ENERGIES AND EXCESS VOLUMES OF THE MIXTURES ETHANOIC ACID + 1,4-DIOXANE AND OXOLANE

Excess Gibbs energies were determined for ethanoic acid + 1,4-dioxane and for ethanoic acid + oxolane from melting curves. In the case of ethanoic acid + oxolane, where the low temperature part of the melting curve was not measured, dynamic vapour-liquid equilibrium measurements with a circulating still were also performed. Both systems show negative excess Gibbs energies, with oxolane a little more negative than dioxane. Combined with literature values of excess enthalpies, excess entropies could be calculated. These are strongly negative for the oxolane mixture, but small and positive for the dioxane mixture. Apparently the total dipole moment plays a much more significant role for complexation than the group contribution. The excess volumes are all negative; for the oxolane systems a little more than for the dioxane system. © 1990.