Towards a better understanding of the parameter Ei/E in the characterization of polar liquids.

In the two previous papers [Stengele, A., Rey, St., Leuenberger, H., 2001. A novel approach to the characterization of polar liquids. Part 1: pure liquids. Int. J. Pharm. 225, 123-134; Stengele, A., Rey, St., Leuenberger, H., 2002. A novel approach to the characterization of polar liquids. Part 2: binary mixtures. Int. J. Pharm. 241, 231-240] it was shown, that the Clausius-Mossotti-Debye equation for the quasi-static dielectric constant (epsilon) can be extended to liquids if the parameter Ei/E is introduced. Ei corresponds to the local mean field due to close molecule-molecule interactions after the application of an external electric field E. In the present paper, it is demonstrated that the value of Ei/E at room temperature can be (1) related to the density of hydroxy groups and the density of the square of the dipole moment per molar volume for polar liquids and (2) also to the total (deltat) and partial solubility parameter, for polar (deltap) and hydrogen bond forming molecules (deltah).