Measurement and prediction of solid–liquid phase equilibria for systems containing biphenyl in binary solution with long-chain n-alkanes

Solid–liquid equilibria of the n-alkanes (n-octadecane, n-eicosane, n-tetracosane, n-pentacosane, n-triacontane) in biphenyl were measured by DSC 7 (Perkin-Elmer). It was found that all systems are simple eutectic. The solubility of the biphenyl in n-alkanes was studied in the temperature range 301–370 K. The experimental results were correlated using modified UNIFAC (Larsen and Gmehling versions) and ideal models. Good representation of solubility diagrams was obtained using partly readjusted UNIFAC parameters of Larsen version. Taking into account the large range of applicability of UNIFAC and the predictions of the activity coefficients for many other components in different classes of mixtures, we can conclude that the new experimental data for the systems mentioned in this work should be included in the database used by UNIFAC in order to evaluate better interaction parameters and to improve predictions.