Measurements and Prediction of Melting Temperature and Eutectic Point of Binary Fatty Acids Based on Wilson Activity Model

There is a great technical interest in solid-liquid equilibrium (SLE) of binary fatty acids. Mainly, these substances are used for the design, development, and operation of many industrial processes because of the application in many manufacturing fields such as the cosmetic, pharmaceutical and biotechnology industries. In this study, an approach is presented for binary fatty acid mixtures to estimate the melting temperatures as a function of mole fraction in the solid-liquid phase equilibrium. Derivation of the Wilson model was developed to predict the melting temperatures and latent heat to achieve eutectic points of capric acid, undecylic acid, pentadecylic acid, and margaric acid binary mixtures. The results showed that in the all binary mixtures, the eutectic point is near to a lighter compound except capric+undecylic acid because of lower melting temperature of undecylic acid than capric acid. Comparison of experimental and thermodynamic studies revealed the low deviations between measured and calculated values obtained in this study.