Dielectric studies of binary mixtures of N-formylmorpholine and an aromatic hydrocarbon. Comparison with theory.

Relative permittivity of binary mixtures of highly polar N-formylmorpholine + benzene, + toluene, + ethylbenzene, + o-xylene, + m-xylene, + p-xylene and + mesitylene were studied over the whole mole fraction range at 298.15 K. The excess polarizability, DeltaP and excess permittivity, Deltae calculated show that at least two types of molecular interactions occur in these binary mixtures. One of these increases the polarizability sharply, which corresponds to parallel configurations of nearest dipoles and the second decreases the polarizability, which corresponds to antiparallel configuration of the dipoles. Dielectric theory of Frolich successfully predicted the permittivity and dielectric behaviour of a binary mixture, containing polar-non polar solvents. (C) 2002 Elsevier Science B.V. All rights reserved.