Study of solute–solvent interaction through dielectrics properties of N,N-dimethylacetamide in ethanolamine

Abstract

Dielectric relaxation study on N, N-Dimethylacetamide–Ethanolamine binary mixtures has been carried out at 11 concentrations over the frequency range of 10 MHz to 20 GHz at 15, 25, 35, 45 °C using Time Domain Reflectometry (TDR) technique. The mixtures exhibit a principle dispersion of the Davidson–Cole relaxation type at microwave frequencies. The least squares fit method has been used to obtain the static dielectric constant ( ε o) and relaxation time ( τ). By using these dielectric parameters, the excess permittivity ( ε E), excess inverse relaxation time (1/ τ) E, Kirkwood correlation factor ( g eff), Bruggeman factor ( f B) are also obtained for investing the solute–solvent interaction. The excess permittivity values are found to be positive at all temperatures and concentrations indicate information of monomeric or polymeric structures which increases the total number of dipoles in the system. The excess inverse relaxation time (1/ τ) E are found to be negative for all temperatures under study indicates that dipoles rotate slowly in the mixtures due to formation of more multimers. The values of the Kirkwood factor (g) indicates that the parallel alignment of dipoles tends to reduced with the rise in temperature and with increase in volume fraction of DMA in the solution. The plots for f B are deviated from ideal value which shows the existence of intermolecular interaction between DMA and ETA.