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Nano WO 3 ‐Catalyzed One‐Pot Process for Mild Oxidative Depolymerization of Lignin and its Model Compounds
Author(s) -
Liang Jing,
Wang MengXiao,
Zhao YunPeng,
Yan WeiWei,
Si XingGang,
Yu Guo,
Cao JingPei,
Wei XianYong
Publication year - 2021
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.202100670
Subject(s) - depolymerization , lignin , organosolv , chemistry , catalysis , organic chemistry , biopolymer , levulinic acid , green chemistry , monomer , hydrogen peroxide , reaction mechanism , polymer
Abstract Despite challenges related to the robust and irregular structure of lignin, the valorization of this aromatic biopolymer has aroused great interest. However, the current methods exhibit problems such as harsh reaction conditions, complicated operation, and difficult recovery of catalyst. Herein we present a one‐pot process for the mild oxidative depolymerization of lignin and lignin model compounds catalyzed by nano WO 3 , along with tert ‐butyl hydrogen peroxide (TBHP) as the oxidant and NaOH as the additive, which exhibits advantages of both homogeneous and heterogeneous catalysis. Under the optimized condition, it yielded 80.4 wt % of liquid oil from organosolv lignin with 7.6 wt % of vanillic acid as the main monomer product, accounting for 91.6 wt % monomeric selectivity. Mechanism studies on the model substrate suggest that the reaction proceeds via an oxidation of C α −OH to C=O followed by C−O bond cleavage to afford phenol and ketone products which may undergo further oxidation to produce aromatic carboxylic acids. We have developed an operationally simple procedure for mild fragmentation of lignin and lignin model compounds with excellent yields, which provides the potential to expand the existing lignin usage from energy source to value‐added commodity chemicals.