Activation of lignin by selective oxidation: An emerging strategy for boosting lignin depolymerization to aromatics. (November 2019)

• Record Type: Journal Article
• Authors: Yu, Xiaona; Wei, Ziqing; Lu, Zhixian; Pei, Haisheng; Wang, Hongliang
• Is Part Of: Bioresource technology. Volume 291(2019)
• Publication Date: 2019-11
• Subjects: Lignin -- Pre-oxidation -- Lignin activation -- Lignin depolymerization -- Aromatics; Biomass -- Periodicals; Biomass energy -- Periodicals; Bioremediation -- Periodicals; Agricultural wastes -- Periodicals; Factory and trade waste -- Periodicals; Organic wastes -- Periodicals; Bioénergie -- Périodiques; Déchets agricoles -- Périodiques; Déchets industriels -- Périodiques; Déchets organiques -- Périodiques; Déchets (Combustible) -- Périodiques; 662.88
• DOI: 10.1016/j.biortech.2019.121885
• Languages: English
• ISSNs: 0960-8524

Abstract

Highlights: Efficient conversion of lignin to aromatics should deal with the condensation issue. The activation of β-O-4 linkages is crucial for busting lignin depolymerization. Oxidation of CαH-OH to Cα = O in β-O-4 can obviously improve lignin depolymerization. Various oxidation strategies can be used to selectively oxidize lignin side chains. Abstract: Lignin is the most abundant, renewable aromatic resource on earth and holds great potential for the production of value-added chemicals. The efficient valorization of lignin requires to deal with several formidable challenges, especially to prevent it from re-condensation reactions during its depolymerization. Recently, a strategy involving the activation of lignin side chains by selective oxidation of the benzylic alcohol in β-O-4 linkages to facilitate lignin degradation to aromatic monomers has become very popular. This strategy provides great advantages for lignin selective degradation to high yields of aromatics under mild conditions, but requires an additional pre-oxidation step. The purpose of this review is to provide the latest cutting-edge innovations of this novel approach. Various catalytic systems, including those using chemo-catalytic methods, physio-chemo catalytic methods, and/or bio-catalytic methods, for the oxidative activation of lignin side chains are summarized. By analyzing the current situation of lignin depolymerization, certain promising directions are emphasized.