Biomimetic Fenton‐Catalyzed Lignin Depolymerization to High‐Value Aromatics and Dicarboxylic Acids

By mimicking natural lignin degradation systems, the Fenton catalyst (Fe 3+ , H 2 O 2 ) can effectively facilitate lignin depolymerization in supercritical ethanol (7 MPa, 250 °C) to give organic oils that consist of mono‐ and oligomeric aromatics, phenols, dicarboxylic acids, and their derivatives in yields up to (66.0±8.5) %. The thermal properties, functional groups, and surface chemistry of lignin before and after Fenton treatment were examined by thermogravimetric analysis, pyrolysis–gas chromatography–mass spectrometry, 31 P NMR spectroscopy, and X‐ray photoelectron spectroscopy. The results suggest that the Fenton catalyst facilitates lignin depolymerization through cleavage of β‐ether bonds between lignin residues. The formation of a lignin–iron chelating complex effectively depresses lignin recondensation; thus minimizing charcoal formation and enhancing the yield of liquid products.