The oxidative delignification of wood in supercritical carbon dioxide: The functionalization of coniferous lignin

Changes in the content of lignin functional groups during low-temperature delignification under the action of hydrogen peroxide in supercritical (SC) CO(2) in the preparation of fibrous cellulose half-finished product were considered. The action of the oxidizer caused changes in the molecular weight characteristics of lignins. The experimental data showed the occurrence of both oxidation and substitution processes. Oxidation in SC CO(2) resulted in the formation of water- and alkali-soluble medium- and low-oxidized lignins because of decreased oxidizer consumption.