Dielectric Studies. XIII. Relaxation Processes of Some Haloethanes in Cyclohexane Solution

The dielectric absorption of several haloethanes in cyclohexane solution has been determined at microwave frequencies and the static dielectric constant at 2 Mc/sec. The dielectric data have been used to yield mean relaxation times and apparent dipole moments. Pentachloro-,1,1,2,2-tetrabromo-, and 1,1,1,2-tetrachloroethane which have a high potential-energy barrier to internal rotation are characterized by a single relaxation time and a distribution coefficient of zero, whereas those with low-energy barriers of about 3 kcal/mole all show a definite distribution coefficient which suggests a contribution from an intramolecular relaxation process.