Excess Properties:

The figures below show the excess enthalpies (H-Excess), free energies (G-Excess) and entropies (S-Excess, times temperature T) of the n-heptane (1) - 1-butanol (2) system at T=50°C. The experimental data was fitted to a polynomial representation in order to allow for a comparison on the experimental and calculated TS(Exc) = G(Exc) - H(Exc) values. As is visible from the vapor-liquid binary phase diagrams, COSMOtherm is able to predict the quite unusual course of TS-Excess qualitatively correct. Taking into account the relatively small absolute values of the excess properties in this system, the quantitative correlation of experimental and predicted COSMOtherm values is excellent.

Experimental data:

- A. Gusovius, Diplomarbeit, TU Darmstadt, Germany, 1997
- C. W. Smith and E. W. Engel, J. Amer. Chem. Soc. 51 2660 (1929)

COSMOtherm calculations were done using Turbomole BP-TZVP-COSMO with the standard parametrization for this method/basis set combination.