Abstract
A new, highly sensitive vapor pressure apparatus has been used to study very dilute solutions of benzene, of cyclohexane, and of mixtures of cyclohexane and cyclohexanol in water at temperatures from 15 to 45°C. The results have been used to calculate the enthalpy, free energy, and heat capacity of transfer of benzene and of cyclohexane from the vapor phase into water at infinite dilution. Values of the equilibrium constant and the enthalpy change have been determined for the reactions
and
occurring in dilute aqueous solution. Of particular interest is the result that the enthalpy of dimerization is positive for the two association reactions [4.0±1.0 kcal-mol−1 for reaction (A) and 3.45±0.16 kcal-mol−1 for reaction (B) at 25°C]. The heat capacity change for reaction (B) is −61±39 cal-K−1-mol−1. The results are discussed in relation to current theories and descriptions of hydrophobic interactions.
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Tucker, E.E., Lane, E.H. & Christian, S.D. Vapor pressure studies of hydrophobic interactions. formation of benzene-benzene and cyclohexane-cyclohexanol dimers in dilute aqueous solution. J Solution Chem 10, 1–20 (1981). https://doi.org/10.1007/BF00652776
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DOI: https://doi.org/10.1007/BF00652776