Study of dielectric relaxation and hydrogen bonding in water + 2-butoxyethanol mixtures using TDR technique

The complex permittivity of 2-butoxyethanol (BE)–water mixtures over entire concentrations has been measured as a function of frequency from 10 MHz to 30 GHz. All spectra were fitted using Cole–Davidson (CD) relaxation spectral function which gives an asymmetric distribution of relaxation times. As composition of butoxyethanol in water increases the width of distribution function broadens. By using least squares fit method the dielectric parameters such as static dielectric constant (ɛ0), dielectric constant at high frequency (ɛ∞), relaxation time (τ) and relaxation distribution parameter (β) were extracted from complex permittivity spectra at temperature range from 25 °C to 0 °C. The heterogeneous interaction in unlike molecules and intramolecular interaction in same molecules has been discussed using the excess dielectric properties, Kirkwood correlation factor, thermodynamic properties and Bruggeman factor.

Figure shows the frequency dependent complex permittivity spectra: (a) dielectric permittivity (ɛ′) and (b) dielectric loss (ɛ″) for 2-butoxyethanol–water mixtures at 25 °C.Figure optionsDownload as PowerPoint slideHighlights
► Complex permittivity spectra of 2-butoxyethanol (BE)–water mixtures were observed.
► As composition of BE in water increases the dielectric permittivity decreases.
► From water to BE the dielectric loss peak shifts towards lower frequency.
► The nonlinear behavior of ɛ0 and τ against XW shows heterogeneous interaction.
► Kirkwood correlation factor and excess properties confirms heterogeneous interaction.