Dielectric relaxation study of binary mixture of sulfolane and N,N-dimethylacetamide in benzene solution using microwave absorption data

Abstract

The dielectric constant (\( \varepsilon ^{\prime} \)) and dielectric loss (\( \varepsilon ^{\prime \prime} \)) for dilute solutions of the binary mixture of different molar concentrations of sulfolane and DMA in benzene solution have been measured at 9.885 GHz at different temperatures by using standard microwave techniques. Following the single frequency concentration variational method, the dielectric relaxation time (\( \tau \)) and dipole moment (\( \mu \)) have been calculated. It is found that dielectric relaxation process can be treated as the rate process, just like the viscous flow. The presence of solute–solute molecular associations in benzene solution has been proposed. Energy parameters (\( \Updelta H_{\varepsilon } ,\Updelta F_{\varepsilon } ,\Updelta S_{\varepsilon } \)) for dielectric relaxation process of binary mixture at 50 % mole fraction in benzene at different temperatures have been calculated and compared with the corresponding energy parameters (\( \Updelta H_{\eta } ,\Updelta F_{\eta } ,\Updelta S_{\eta } \)) for the viscous flow.