Oxidative Catalytic Fractionation and Depolymerization of Lignin in a One-Pot Single-Catalyst System

• Published in: ACS sustainable chemistry & engineering 2021-06, Vol.9 (23), p.7719-7727
• Main Authors: Du, Xu, Tricker, Andrew W, Yang, Weisheng, Katahira, Rui, Liu, Wei, Kwok, Thomas T, Gogoi, Parikshit, Deng, Yulin
• Format: Article
• Language: English
• ISSN: 2168-0485; 2168-0485
• DOI: 10.1021/acssuschemeng.0c08448

It has been known that the yield of lignin monomers during lignin depolymerization is limited by the irreversible condensations of lignin in the fractionation and/or depolymerization process. In this study, we report a new oxidative catalytic fractionation (OCF) process with a simple and effective one-pot but two-step approach to depolymerize lignin to lignin-derived chemicals (LDCs) using polyoxometalate (POM) as the only catalyst. First, the POM effectively catalyzed the methoxylation of the active α-OH groups of lignin in a methanol and water mixture at low temperature (100 °C), and 96% of the stabilized lignin in the lignocellulose sawdust was extracted to the solution simultaneously. Then the lignin solution was heated to an elevated temperature (140 °C) in the same solvent. As a result, 74.0 wt % of the lignin (based on the weight of the Klason lignin in the wood) was converted to LDCs, including 45.9 wt % aromatic monomers.