Dielectric relaxation time and dipole moment of isometric butanols in benzene solutions.

Measurements of static permittivity at 100 KHz, refractive index (for Sodium D line) and complex permittivity at 7.73 GHz have been made for Butane 1-01, Iso-butyl alcohol, Sec. butyl alcohol and Tert. butyl alcohol at 35°C. in dilute solutions of benzene. Dielectric relaxation time (τ) have been determined following the three methods, viz., method of Higasi et al, Gopal Krishna's method and Higasi's method. The value of τ and the distribution parameter (α) show evidence for existence of morethan one relaxation mechanism. This has been interpreted in terms of intramolecular orientation of O-H. group occuring simultaneously with the end over end molecular orientation. The > values for all these compounds have been found much larger than the corresponding compounds of similar structure. This behaviour has been explained as due to the formation of dimers by association and solute solvent interaction. This is also confirmed from the tan δ concentration curves. The values of the dipole moments determined from the Higasi's method, Gopal Krishna's method and Guggenheim's method are found to be in good agreement.