Dielectric studies. Part XXIII. Relaxation data and apparent dipole moments of aniline and some disubstituted aromatic amines

Dielectric studies have been carried out at microwave frequencies on dilute solutions of aniline, p-chloro-, p-bromo-, and m-chloro-anilines, and o-, m-, and p-toluidines at 25 °C in cyclohexane and p-xylene. The static dielectric constant has also been measured at 2 MHz. In addition o- and m-toluidines have been measured at 50 °C and p-toluidine at 15, 35, and 50 °C.The dielectric results, particularly those at 70.01 GHz, establish that there is more than one relaxation process present and the data have been analyzed on a two relaxation time model, the longer of which τ1, is identified as molecular relaxation. The cause of the lower electric dipole moments found from this method as opposed to the non-dielectric absorption methods is discussed. It follows that there is either an additional higher frequency dispersion or (and) a high atomic polarization for aniline and o-, m-, and p-toluidines. Work at still higher frequencies is required to study this further and to establish more precise values of τ2.