Analysis of temperature-frequency dependences of dielectric permittivity and specific conductivity of vanillin

Vanillin has a wide application. It is a large-tonnage product obtained from plant biomass. The frequency-temperature dependences of the specific electrical conductivity and the components of the complex dielectric constant of vanillin were obtained by dielectric spectroscopy in the frequency range of 6.28 $\cdot$ 10$^{-2}$–6.28 $\cdot$ 10$^7$ rad/s and temperatures 153-433 K. The dependencies were analyzed using the Debye, Gavrilyak–Negami and Cole–Cole models. Significant changes in the electrophysical properties of vanillin during melting were shown. The presence of relaxation processes in the low, medium and high frequencies region was established. Their activation energies were determined. A comparative analysis of the characteristics of relaxers for a number of model compounds of the lignin structural units was presented in this paper. A comparative analysis of the characteristics of relaxators for vanillin, vanillin alcohol and guaiacol as model compounds of the lignin was carried out. The presence of an electron acceptor carbonyl group coupled with a benzene ring in the vanillin molecule leads to an increase in the activation energy and relaxation time of the $\pi$-electrons.