Study of excess dielectric and thermodynamic parameters of hydrogen bonded system: Isobutanol and ethyl benzoate

The complex dielectric permittivity of polar systems of isobutanol and ethyl benzoate for various mole fractions at different temperatures has been studied by using the open-ended coaxial probe technique method in the microwave frequency range from 20 MHz to 20 GHz. The dipole moment, excess dipole moment, Bruggeman parameter, excess Helmholtz energy, excess permittivity, excess inverse relaxation time, excess thermodynamic values are calculated using experimental results. The optimized geometry, harmonic vibrational wave numbers and dipole moments of pure and equimolar binary mixtures have been calculated theoretically from HF, B3LYP with 6-311G and 6-311G+ basis sets by using Gaussian-03 software. Conformational analysis of the formation of hydrogen bond between isobutanol and ethyl benzoate is supported by the FT-IR, super(1) NMR and molecular polarizability calculations. The calculated wave numbers and dipole moments agree well with the experimental values. Further, the correlations among the parameters have been discussed in detail.