Determination of the total and partial cohesion parameters of lipophilic liquids by gas-liquid chromatography and from molecular properties.
The total and partial cohesion parameters of seven lipophilic liquids (one alkane, two alcohols, one acid, and three esters) have been determined. The proposed procedure involves knowledge of the structure, and determination of dipole moment, refractive index, and dielectric constant of the substances. The total cohesion parameters are experimentally determined for four liquids by gas-liquid chromatography, and also calculated for these and three additional liquids according to Fedors by summation of group increments. The dispersion cohesion parameter is calculated from the refractive index, and the polar cohesion parameter by Taft's polarity function, and Carr's relationship. The hydrogen bonding cohesion parameter is then obtained by difference. The results are self-consistent and coherent. In particular, it may be seen that the difference between the various lipophilic liquids, from the point of view of intermolecular interactions, is essentially due to the variation in strength of hydrogen bonds and dipole-dipole interactions, whereas the interactions stemming from the dispersion forces are similar.
Munafo
A
A
Institut d'Analyse Pharmaceutique, Ecole de Pharmacie, Université de Lausanne, Switzerland.
Buchmann
M
M
Nam-Tran
H
H
Kesselring
U W
UW
D002849:Chromatography, Gas; D006860:Hydrogen Bonding; D008956:Models, Chemical; D008962:Models, Theoretical; D012995:Solubility; D013816:Thermodynamics