MICROWAVE ABSORPTION AND MOLECULAR STRUCTURE IN LIQUIDS .76. RELAXATION BEHAVIOR OF SEVERAL PRIMARY ALCOHOLS IN DIULTE BENZENE AND P-DIOXANE SOLUTIONS

Dielectric constants and losses of methanol, 1-butanol, and 1-decanol have been measured at concentrations of 0.02-0.05 mole fraction in benzene and p-dioxane solutions at wavelengths of 0.20, 1.25, 3.22, 9.8, 24.8, 49.8, and 3 × 106 cm at 25°. Measurements have also been made on 1-butanol in p-dioxane and its mixtures with benzene and n-heptane at 20, 40, and 60° at the same wavelengths. In benzene solutions the arc plots show contributions from two relaxation processes corresponding to relaxation times 2 × 10-12-5 × 10-12 and 13 × 10-12-36 × 10-12 sec. These are attributed to -OH group and molecular reorientation, respectively. In dioxane solutions a symmetrical distribution of relaxation times is found with τ0 = 3 × 10-12-9 × 10-12 sec. In mixtures of benzene and n-heptane with dioxane, 1-butanol also shows a distribution of relaxation times with the distribution parameter, α, decreasing with increasing temperature. Reorientation of alcohol-dioxane complexes of varying sizes seems a plausible explanation for the distribution of relaxation times. Fluctuations of local environment around a reorienting dipole, caused by H-bond forming and breaking, may also account for this behavior. © 1969, American Chemical Society. All rights reserved.