Dielectric Dispersion and Intermolecular Association for 28 Pure Liquid Alcohols. The Position Dependence of Hydroxyl Group in the Hydrocarbon Chain

The dielectric constants and losses of 28 linear alcohols, 1-alkanol (n=3–10), 2-alkanol (n=3–10), 3-alkanol (n=5–10), 4-alkanol (n=7–10), and 5-alkanol (n=9 and 10), have been measured at the frequencies from 1.35 to 4500 MHz at 15, 25, and 35 °C. The Kirkwood–Fröhlich equation was modified so that it could be applied to each dispersion region calculated. The concentration C1 of linear hydrogen-bonded chain polymers, which primary dispersion originates, was evaluated by means of this modified equation. The C1 decreases as the hydroxyl group approaches the center of a molecule, except for propanols and butanols, and also decreases with increasing temperature. For isomeric decanols, for example, the percentages of C1 (C1×100⁄C0) against alcohol gross stoichiometric concentration C0 at 15, 25, and 35 °C are about 71, 63, and 53% for 1-decanol, 52, 40, and 29% for 2-decanol, 22, 17, and 12% for 3-decanol, 11, 7, and 6% for 4-decanol, and 8, 6, and 5% for 5-decanol, respectively. The thermodynamic parameters, ΔF, ΔH, and ΔS, were obtained for dipole relaxation and viscous flow . The ΔFτ decreases, although the ΔHτ and ΔSτ increase, as the hydroxyl group approaches the center of a molecule. The ΔFη increases linealy with the molecular volume, irrespective of the position of the hydroxyl group.