Dielectric relaxation study of solute-solvent interaction between dimethylene chloride and dimethylformamide using time domain reflectometry

The complex permittivity spectra of dimethylene chloride-N, N dimethylformamide were determined in the frequency range of 10 MHz to 20 GHz using time domain reflectometry (TDR) in the temperature range 15 °C to 45 °C for 11 different concentrations of the system. The dielectric parameters viz. static dielectric constant (ε0) and relaxation time (τ) have been obtained by the least squares fit method. Excess properties and Kirkwood correlation factor of the mixtures have been determined. In the case of dimethylene chloride excess permittivity is found to be negative, whereas it is positive in N, N dimethylformamide rich region, except 15 °C. The static dielectric constants for the mixtures have been fitted with the modified Bruggeman model.