The Dielectic properties of Crystalline Alcohols containing sterically hindered Hydroxyl groups

Abstract

It has been previously suggested that the high dielectric absorption of certain crystalline forms of long-chain alcohols is associated with hydrogen-bonding of the hydroxyl groups. This theory is supported by the results given in the present paper, which show that with other alcohols, in which the hydroxyl groups are sterically hindered, the loss is almost completely eliminated. The smallest losses are obtained with triphenylcarbinol and cholesterol which both possess hydroxyl groups embedded in a bulky molecular structure. For the former compound, infra-red data from the literature indicate the absence of any appreciable amount of hydrogen-bonding and are thus in agreement with the evidence from dielectric measurements. High frequency absorption observed in these compounds is considered to be associated with dipole orientation resulting from hindered rotation of the free hydroxyl groups. The effects of steric hindrance of the hydroxyl group are also observed in tert.-butanol.