Intramolecular Dipole Reorientation of Amino Compounds and their Interaction with Solvent Molecules II

Abstract

The dielectric absorption of dilute solutions of chlorocyclohexane, cyclohexylamine, dicyclohexylamine, diphenylamine, N-methyldiphenylamine, and triphenylamine in various solvents has been measured between 0.3 and 135 GHz. The measurements have been carried out at 20 °C and for some solutions also at -30 and 60 °C. The previous measurements made for the compounds have been extended to higher frequencies and improved by a greater number of frequencies. The loss curves have been resolved into multiple absorption regions. A rather much contributing far infrared (FIR) term was necessary to be involved in each analysis. The intramolecular dipole reorientation process in cyclohexylamine is considerably slower than in aniline because of the lack of the mesomeric interaction. In dicyclohexylamine only the overall relaxation was observed at microwave frequencies. Two large regions were resolved for N-methyldiphenylamine at microwave frequencies whilst in diphenylamine the second region likely contributes to the very large FIR region. Evidences for weak association between diphenylamine and the aromatic solvents were obtained.