Dielectric relaxation studies of binary mixtures of tetrahydrofuran and N,N-dimethylformamide in benzene solutions using microwave absorption data

Abstract

The dielectric relaxation times $$ \left( \tau \right) $$ and dipole moments $$ \left( \mu \right) $$ of the binary mixtures of different molar concentrations of tetrahydrofuran (THF) and N,N-dimethylformamide (DMF) in benzene solution have been calculated by using standard standing wave microwave techniques and Gopala Krishna’s single frequency(9.90 GHz) concentration variational method at different temperatures (25, 30, 35, and 40 °C). The energy parameters (∆H e , ∆F e , ∆S e ) for the dielectric relaxation process of THF + DMF binary mixture containing 50 mol% THF have been calculated at different temperatures (25, 30, 35, and 40 °C) and comparison has been made with the corresponding energy parameters (ΔH η , ΔF η , ΔS η ) for viscous flow process. It is found that dielectric relaxation process can be treated as rate process just like the viscous flow process. On the basis of above studies, solute–solute and solute–solvent types of molecular associations have been predicted.