Heats of vaporization and vapor-liquid equilibria in associated solutions containing formic acid, acetic acid, propionic acid and carbon tetrachloride

Tamir, A., Dragoescu, C., Apelblat, A. and Wisniak, J., 1983. Heats of vaporization and vapor-liquid equilibria in associated solutions containing formic acid, acetic acid, propionic acid and carbon tetrachloride. Fluid Phase Equilibria, 10: 9-42. Differential heats of vaporization and vapor-liquid equilibria have been determined for the associated systems acetic acid+carbon tetrachloride at 35°C, propionic acid+carbon tetrachloride, propionic acid+acetic acid, propionic acid+formic acid, acetic acid+formic acid, and carbon tetrachloride+acetic acid+propionic acid at 30°C. A molecular model is established for predicting the vapor compositions and differential heats of vaporization from P-T-X measurements and association constants. The predicted heats of vaporization are in good agreement with the experimental measurements (mean relative deviation less than 5%) for all systems, excluding the systems propionic acid+another acid (mean relative deviation ∼ 10%) for which the association effect was not thoroughly investigated. The heat of vaporization for the ternary system carbon tetrachloride+acetic acid+propionic acid is predicted satisfactorily from the binary measurements. A correlation is developed for calculating differential heats for associated mixtures which does not require a molecular model to be established.