Dielectric Constant of Hydrogen Bonded Liquids. III. Superheated Alcohols

Abstract

The dielectric constants of the eight lowest aliphatic alcohols have been measured from room temperature to their respective critical temperatures. The densities were also measured if they were not previously available. The data were analyzed in terms of Kirkwood's correlation factor based on a model of linear, hydrogen-bonded chains with restricted rotation about the hydrogen bond and variable degree of polymerization. The equilibrium constants are strongly dependent on the size and shape of the alkyl group. —ΔF°298 (kcal/mole; mole fraction units), —ΔH°298 (kcal/mole), and —ΔS°298 (cal/mole·deg) for hydrogen-bond formation in the pure liquid are: MeOH, 3.95, 6.50, 8.56; EtOH, 4.10, 8.63, 15.2; n-PrOH, 3.42, 7.76, 14.6; iso-PrOH, 2.97, 8.64, 19.1; n-BuOH, 3.12, 7.70, 15.4; iso-BuOH, 2.87, 8.73, 19.7; sec-BuOH, 2.05, 7.97, 19.9; tert-BuOH, 0.98, 7.28, 21.2.