Dielectric relaxation and thermodynamic study of Dimethylformamide/1,4-Butanediol binary mixtures in the temperature range 298K–323K

• Published in: Physica. B, Condensed matter Condensed matter, 2020-07, Vol.588, p.412142, Article 412142
• Main Authors: Prasad, T. Vamshi, Vishwam, T., Manjula, V., Raju, K.C. James, Aparna, Y.
• Format: Article
• Language: English
• Subjects: Binary mixtures; Butanediol; Dielectric properties; Dielectric relaxation; Dimethylformamide; Dipole moment; Dipole moments; Effective Kirkwood correlation factor (geff); Enthalpy; Excess parameters; Heat transfer; Helmholtz energy; Microwave frequencies; Mixing rules; Molar volume; Parameters; Permittivity; Polynomials; Refractivity; Relaxation time; Stability analysis; Stress relaxation; Temperature; Thermal expansion; Thermodynamics
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/j.physb.2020.412142

In the present paper, the permittivity of Dimethylformamide (DMF) with 1,4-Butanediol (BD) binary mixtures are determined at the temperature range of 298 K–323 K in the microwave frequency. Dipole moment (μ), excess molar volume (VmE), partial molar volume (Vm,i), excess permittivity (εE), excess refractive index (nDE), excess inverse relaxation time (1/τ)ε, thermal expansion coefficient (αP), excess Helmholtz energy (ΔFE) are determined at different temperatures. Redlich-Kister polynomial equation is used to fit the excess parameters. Havriliak-Negami equation is used to analyse the relaxation time of the binary mixtures throughout the measured temperature range. The heteromolecular interaction between DMF and 1,4-Butanediol binary mixtures are interpreted in terms of Kirkwood correlation (geff) factor. The stability of the system is analysed from the activation energy (ΔG*), enthalpy (ΔH*) and entropy (ΔS*) parameters. The various mixing rules were applied in order to estimate the permittivity and refractive indices of the binary system at different temperatures. [Display omitted] •Study of molecular interaction between 1,4-Butanediol and DMF binary mixtures.•Microwave dielectric relaxation studies of mixtures at different temperatures.•Excess molar volume is negative indicate intermolecular interaction in the mixtures.•Gibbs free energy values are positive indicates H- bonds in the mixtures.•Excess Helmholtz energy values confirms the presence of multimers in the solution.