Features of redox properties of phenolic structures of coniferous and deciduous lignins in the solid and liquid phase

Phenolic hydroxyl groups are the main reaction centers in lignin macromolecules. They form the redox properties of a natural polymer. Spatial fixation of lignin redox groups in the solid phase leads to differences in reactivity compared to lignin solutions. Slightly modified samples of dioxane lignin were obtained from different wood species: coniferous (spruce, juniper) and deciduous (aspen) wood species were chosen as objects of research. The lignins were characterized by functional composition, macromolecular and reaction properties. A new methodological approach to the assessment of the lignin redox properties in the solid phase, modeling its state in the plant matrix, has been proposed. The possibility of using of polystyrene as an analytical matrix in the study of redox properties with the participation of phenolic hydroxyl groups of lignin is shown by the method of dielectric spectroscopy. Membrane electrodes based on lignin films in polystyrene were obtained. The rate of oxidation of lignin samples in the solid state was determined on the basis of chronopotentiometric dependencies.