Studies on the Reactions of Phenolic and Non-Phenolic Lignin Model Compounds with Chlorine Dioxide

Abstract

Abstract The reaction between chlorine dioxide and four different lignin model compounds (phenolic and non-phenolic, with or without an α-hydroxyl group) are studied. The key difference with previous studies is the effective elimination of hypochlorous acid by sulfamic acid during chlorine dioxide treatment. The elimination of hypochlorous acid, an important intermediate formed during chlorine dioxide bleaching, makes it possible to study the consumption of the lignin model compounds solely as a result of the action of chlorine dioxide. Based on almost closed mass balances for the substrate and atomic chlorine it is found that the reaction between ClO2 and lignin model compounds is generally characterized by three independent parallel reactions: 1) demethylation, 2) formation of 2-methoxy-p-quinone and 3) formation of muconic acid monomethyl ester and/or its derivatives. Although, the importance of each reaction depends on the functional groups of the substrate, the demethylation reaction is the most impo...