Determination, Correlation, and Thermodynamic Analysis of the Solid–Liquid Phase Equilibrium of 1,4-Dicyanobenzene in Pure Solvents at Various Temperatures

The solubility of 1,4-dicyanobenzene (DCB) in 17 neat solvents, that is, methanol, ethanol, n-propanol, isopropanol, acetone, ethyl acetate, ethyl formate, methyl acetate, cyclohexanone, cyclopentanone, tetrahydrofuran, 2-butanone, acetonitrile, chloroform, 2-pentanone, dichloromethane, and diethyl ether, was measured via a gravimetric method from 272.95 to 324.15 K under ambient pressure. Within the experimental temperature range, the mole fraction solubility of DCB increased with the rising temperature in all selected solvents, and the order of magnitude is cyclopentanone > dichloromethane > cyclohexanone ≈ tetrahydrofuran > chloroform > (acetone, 2-butanone) > 2-pentanone ≈ methyl acetate > ethyl formate > ethyl acetate > acetonitrile > diethyl ether > methanol > ethanol > n-propanol > isopropanol. The solubility of DCB in ketones was much higher than that in ethers and alcohols. The Wilson model, nonrandom two-liquid model, Apelblat equation, and λh equation were employed to mathematically express the solid–liquid phase equilibrium data of DCB. The maximum values of the root-mean-square and relative average deviations were 9.83 × 10–5 and 5.21 × 10–3, respectively, which indicated that good correlation was recorded between the experimental and calculated data. The dissolution enthalpy, entropy, and Gibbs free energy were calculated on the basis of thermodynamic relations and the Wilson model, which revealed that the dissolution of DCB was a spontaneous and endothermic process.