| Abstract |
The surface tensions (gamma(2)) of organic liquids have been shown to correlate with empirical solute parameters by the linear free energy relationship (LSER): gamma(2) = 14.8 + 11.4 R-2 + 10.6 pi(2) + 3.4 (Sigma alpha(2) x Sigma beta(2))(1/2) + 2.95 V-X + 0.87 N-C where R-2, pi(2), Sigma alpha(2), Sigma beta(2), and V-X are medium-insensitive solute parameters representing, respectively, the excess molar refraction, dipolarity, the hydrogen bond acidity and basicity, and the molar volume of the organic liquid. The term N-C, which is specific to the n-alkanes, is a function of the total number of carbon atoms in the n-alkane. The free energy contribution from intermolecular hydrogen bond formation is modeled by using the geometric mean parameter (Sigma alpha(2) x Sigma beta(2))(1/2). This new LSER provides a useful conceptual framework for understanding the interaction of surface molecules with the underlying molecules of the bulk liquid, as well as permitting estimation of surface tension directly from molecular structure. |
