Dielectric studies. Part 11.—Relaxation processes of six monosubstituted benzenes in dilute solution

Abstract

The dielectric absorption at five microwave frequencies of solutions of the monohalobenzenes, nitrobenzene and benzonitrile in p-xylene at 15 and 60°C has been examined. Solutions of nitrobenzene in cyclohexane and carbontetrachloride at 25 and 15°C respectively, and also benzonitrile in cyclohexane at 15°C, have also been studied. All solutions of the halobenzenes may be characterized by a dielectric absorption contribution from one Debye term¹ and are in harmony with the Perrin theory.² None of the systems showed high-frequency absorption of the type reported by Poley³ for the liquid halobenzenes. Some benzonitrile and nitrobenzene systems have definite distribution coefficients which may be resolved into contributions from two relaxation processes, one associated with molecular re-orientation and a longer relaxation time related to the presence of some form of polar aggregate.