Temperature Dependence of Transfer Properties: Importance of Heat Capacity Effects

Gibbs ensemble Monte Carlo simulations were used to calculate precisely the Gibbs free energies, enthalpies, and entropies of transfer for water, 1-butanol, and n-octane between their own liquid phase and a helium vapor phase. It is observed that the temperature dependence of the enthalpy of transfer (i.e., the heat capacity of transfer), and not the temperature-entropy term, dominates the temperature dependence of the Gibbs free energy of transfer. Nevertheless, the curvature induced by the heat capacity in a van't Hoff plot is small, and the van't Hoff equation yields an enthalpy of transfer close to the value calculated directly at the mean temperature.