Dielectric Relaxation and Molecular Structure. XV. A Further Study of the Benzene Effect of 1,2-Dichloroethane and Related Molecules

The dielectric relaxation times, τ, and dipole moments, μ, of 1,2-dichloroethane (A), cis-1,2-dichloroethylene(B), 1,3-dichloropropane(C), o-dichlorobenzene(D), and 1-chloro-2-propanone(E) have been measured in two aromatic and two aliphatic nonpolar solvents. The results are as follows: both the τ and μ of (A) and (E) are exceptionally large in aromatic solvents, showing the benzene effect; (B) and (C) have large τ but normal μ values in aromatic solvents, while (D) shows normal effects of the solvent upon both τ and μ in two different sets of solvents. Finally, the intetmolecular interaction between the solute and the solvent is discussed with special regard to the origin of the benzene effect.