DISQUAC Predictions on Thermodynamic Properties of Ternary and Higher Multicomponent Mixtures. 3. Results for HE of Ternary Mixtures Containing One Alcohol, One Polar Compound, and One Hydrocarbon or Two Alcohols and One Hydrocarbon or a Polar Compound, or Three Alkanols

DISQUAC predictions on molar excess enthalpies, H E, are shown for a set of 67 ternary mixtures formed by one alcohol, one active compound (not self-associated), and one hydrocarbon; two alkanols and one hydrocarbon; two alkanols and one polar compound; or three alkanols. DISQUAC provides reliable predictions on H E (≈8%) for the ternary mixtures considered using binary interaction parameters only, i.e., neglecting ternary interactions. Differences between experimental results and theoretical calculations are of the same order for the ternary mixtures and for the constituent binaries. On the other hand, predictions are practically independent of the mixture compounds or of the number of contacts present in the solution. The poorer results are obtained for systems with a binary that shows strongly negative deviations from Raoult's law. A systematic comparison between DISQUAC results and those from the Dortmund UNIFAC model is presented. DISQUAC improves UNIFAC predictions, as well as those from ERAS for 1-alkanol + oxaalkane + alkane mixtures. More complex association models yield results that are similar to those from DISQUAC. Therefore, DISQUAC should be applied when the interaction parameters used are available. The interaction parameters used are valid for the description of the thermodynamic properties of binary mixtures (vapor−liquid, solid−liquid, and liquid−liquid equilibria, H E, and the molar excess heat capacity at constant pressure, ) as well as for predictions on vapor−liquid equilibria, H E, and for ternary mixtures.