EFFECTS OF SOLVENT MEDIUM ON SOLUBILITY .5. ENTHALPIC AND ENTROPIC CONTRIBUTIONS TO THE FREE-ENERGY CHANGES OF DISUBSTITUTED BENZENE-DERIVATIVES IN ETHANOL WATER AND ETHANOL CYCLOHEXANE MIXTURES

The solubility at four different temperatures in water, cyclohexane, and mixtures of water and ethanol and ethanol and cyclohexane of nine derivatives of the structure pX1C6H4X2, together with their heats of fusion are reported. The enthalpy and entropy of mixing (ΔHM and ΔSM, respectively), and also the excess free energy (ΔGE) for pure solvents and several compositions of solvent mixtures were calculated. The enthalpic and entropic contribution to the free energy of transfer for water: solvent mixtures was also calculated for each compound. Solvent systems may be classified by means of the enthalpic–entropic relationships exhibited by the series in each case. Copyright © 1990 Wiley‐Liss, Inc., A Wiley Company