Dielectric relaxation study of some substituted anilines in various non-polar solvents

Abstract

Abstract The dielectric permittivity (ϵ′) and dielectric loss (ϵ″) have been measured at 9.945 GHz for 2-chloro-6-methylaniline, 3-chloro-2-methylaniline, 2-chloro-4-methyl-aniline, 4-chloro-2-methyl-aniline and 5-chloro-2-methyl-aniline in various solvents, e.g. n-heptane, benzene, cyclohexane, carbon tetrachloride and decalin at 35°C. The static permittivity (ϵ o ) at 300 KHz and high frequency limiting permittivity (ϵ ∞ ) have also been measured at 35°C. The data are analysed by Higasi's method in terms of the so-called slopes, a o , a′, a″ and a ∞ The values of relaxation time, distribution parameter (α), and the difference (a ∞ −a D ) so obtained, indicated the existence of more than one relaxation mechanism. This has been interpreted in terms of the intramolecular rotations of the amino group occurring simultaneously with the overall molecular orientation. The investigation also includes the determination of free energies of activation ΔF ϵ , ΔF η and the dipole moment μ of these substituted anilines in different solvents. Discrepancies have been explained in terms of solute-solvent interactions.