DIELECTRIC-RELAXATION STUDIES OF N,N-DI-METHYLFORMAMIDE PLUS DIMETHYLSULFOXIDE MIXTURES IN BENZENE

Single frequency concentration vibrational method of Gopalakrishna have been used to determine the dielectric relaxation time (tau) of dilute solutions of dimethylsulphoxide (DMSO), N,N-dimethylformamide (DMF) and DMF-DMSO mixtures in benzene at 25, 30, 35 and 40-degrees-C by standing wave techniques at 9.174 GHz. Energy parameters for dielectric relaxation process such as DELTAH(epsilon), DELTAF(epsilon) and DELTAS(epsilon), for DMF-DMSO mixtures containing 17 mole% DMSO have been evaluated and compared with the corresponding energy parameter for viscous flow process. Variation of tau for DMF-DMSO mixtures in benzene as a function of mole fraction of DMSO (X(DMSO)) at 25, 30, 35 and 40-degrees-C has been used to indicate change in molecular interactions between DMSO and DMF with change in temperature.