Dielectric Studies on Hydrogen Bonded Polar Binary Mixtures of Alkyl p -Hydroxy Benzoates and Isopropanol

摘要

The dielectric behavior of the polar binary mixture of alkyl p-hydroxy benzoates (where alkyl carbon number n varies from 2 to 9), isopropanol for various volume fractions in nonpolar solvent benzene is studied using plunger and cavity perturbation techniques in the microwave frequency range at 10 GHz (X band), HP impedance analyzer at 1 kHz, 10 kHz, 100 kHz, 1 MHz, 10 MHz and Abbe’s refractometer for optical (1015 Hz) frequency region. Hamiltonian quantum mechanical calculations such as AM1, PM3 and MNDO optimized converged geometry operation is performed by using Spartan Modeling software for both pure and binary systems of alkyl p-hydroxy benzoates and isopropanol. Dipole moments of the binary mixtures are calculated from the dielectric data using Higasi’s method and compared with the theoretical results. Conformational analysis of the formation of hydrogen bond between alkyl p-hydroxy benzoate and isopropanol is supported by the FT-IR spectra. The average relaxation times are calculated from their respective Cole–Cole plots.