The Role of Alkali-Hydrogen Peroxide during Pulp Treatment

Abstract

Semi-quantitative method was developed for the determination of α-carbonyl structure in solid lignin. Deuteride reduction followed by nitrobenzene oxidation was applied to oxygen bleached softwood kraft pulp (NOKP) in order to evaluate the reactivity of hydrogen peroxide with α-carbonyl structures in lignin. We already showed that hydrogen peroxide attacked α-carbonyl structures in lignin very clearly during milled wood lignin treatment. However, when NOKP and hydrogen peroxide treated NOKP were analyzed by this method, the role of hydrogen peroxide was not clearly observed in terms of the content α-carbonyl structure. By the analysis of alkali treated NOKP without hydrogen peroxide, it was suggested that, at the hydrogen peroxide treatment, the effect of hydrogen peroxide on the α-carbonyl structure might be hidden by the generation of α-carbonyl structure and that actually hydrogen peroxide effectively degrades those newly produced structures. Hydrogen peroxide was found to play such a “hidden role” not only for newly produced α-carbonyl structures but also for the newly produced permanganate consuming substances during the treatment.