Solid–Liquid Phase Equilibrium of trans-Cinnamic Acid in Several Alcohols: Measurements and Thermodynamic Modeling

The solubilities of trans- cinnamic acid ( t -CA) in methanol, ethanol, propanol, n -butanol, isopropyl alcohol, and isobutyl alcohol were measured by a synthetic method at temperatures ranging from (283.15 to 333.15) K. The modified Apelblat equation, the λh equation, and activity coefficient models (nonrandom two-liquid, NRTL; universal quasichemical, UNIQUAC) were used to correlate these data. It was found that all of the models show good agreement with the experimental data, and the modified Apelblat equation and NRTL model give better correlation results. Furthermore, on the basis of the NRTL model and experimental data, the thermodynamic excess functions ( G E, S E, H E ) of t -CA + alcohols (methanol, ethanol, propanol, n- butanol, isopropyl alcohol, and isobutyl alcohol) system were determined.