Dielectric Relaxation in Liquid Alcohols and Diols

Abstract

The temperature dependence of the dielectric relaxation time has been investigated from —5° to 50°C for ethanol—cyclohexane solutions from 1.0 to 0.25 mole fraction ethanol. The previously observed maximum in the relaxation time around equimolar composition is explained by a hydrogen‐bonded switching mechanism. Measurements of dielectric relaxation from 5° to 50°C have been carried out on three isomeric butanediols which differ in the separation of the two OH groups along the carbon skeleton. The differences in relaxation times among the three isomers can be explained by the switching mechanism suggested by the results for the ethanol—cyclohexane solutions. The dielectric relaxation times of n‐butanol from 5° to 50°C have also been determined. The chain‐length dependence of the dielectric relaxation time of the normal aliphatic alcohols is discussed in terms of the proposed mechanism.