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Efficient O-demethylation of lignin-derived aromatic compounds under moderate conditions
Lignin is a potential feedstock to produce renewable aromatic chemicals. However, lignin-derived aromatics are heavily methoxylated, which affects their reactivity in some downstream valorization attempts. Herein, we report an efficient method for the demethylation of the aromatics derived from lign...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
The Royal Society of Chemistry
2023
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9936356/ https://www.ncbi.nlm.nih.gov/pubmed/36816077 http://dx.doi.org/10.1039/d3ra00245d |
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author | Wang, Yueqing Chen, Mingjie Yang, Yang Ralph, John Pan, Xuejun |
author_facet | Wang, Yueqing Chen, Mingjie Yang, Yang Ralph, John Pan, Xuejun |
author_sort | Wang, Yueqing |
collection | PubMed |
description | Lignin is a potential feedstock to produce renewable aromatic chemicals. However, lignin-derived aromatics are heavily methoxylated, which affects their reactivity in some downstream valorization attempts. Herein, we report an efficient method for the demethylation of the aromatics derived from lignin depolymerization using acidic concentrated lithium bromide (ACLB) under moderate conditions (e.g., 1.5 M HCl, 110 °C, and 2 h). Aromatics with one or two methoxy groups (G-type and S-type), alkyl hydroxyl and carbonyl groups, and electron-donating and electron-withdrawing substituents were used to investigate the demethylation mechanisms. S-type aromatics were demethylated faster than their G-type analogs. Alkyl hydroxyl groups were brominated under the conditions. Carbonyl groups (aldehydes and ketones) promoted unwelcome condensation. Electron-donating substituents promoted demethylation, whereas electron-withdrawing substituents retarded the demethylation. An ortho-carboxylic group enhanced the demethylation because of the formation of a stable intermediate. |
format | Online Article Text |
id | pubmed-9936356 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2023 |
publisher | The Royal Society of Chemistry |
record_format | MEDLINE/PubMed |
spelling | pubmed-99363562023-02-18 Efficient O-demethylation of lignin-derived aromatic compounds under moderate conditions Wang, Yueqing Chen, Mingjie Yang, Yang Ralph, John Pan, Xuejun RSC Adv Chemistry Lignin is a potential feedstock to produce renewable aromatic chemicals. However, lignin-derived aromatics are heavily methoxylated, which affects their reactivity in some downstream valorization attempts. Herein, we report an efficient method for the demethylation of the aromatics derived from lignin depolymerization using acidic concentrated lithium bromide (ACLB) under moderate conditions (e.g., 1.5 M HCl, 110 °C, and 2 h). Aromatics with one or two methoxy groups (G-type and S-type), alkyl hydroxyl and carbonyl groups, and electron-donating and electron-withdrawing substituents were used to investigate the demethylation mechanisms. S-type aromatics were demethylated faster than their G-type analogs. Alkyl hydroxyl groups were brominated under the conditions. Carbonyl groups (aldehydes and ketones) promoted unwelcome condensation. Electron-donating substituents promoted demethylation, whereas electron-withdrawing substituents retarded the demethylation. An ortho-carboxylic group enhanced the demethylation because of the formation of a stable intermediate. The Royal Society of Chemistry 2023-02-17 /pmc/articles/PMC9936356/ /pubmed/36816077 http://dx.doi.org/10.1039/d3ra00245d Text en This journal is © The Royal Society of Chemistry https://creativecommons.org/licenses/by-nc/3.0/ |
spellingShingle | Chemistry Wang, Yueqing Chen, Mingjie Yang, Yang Ralph, John Pan, Xuejun Efficient O-demethylation of lignin-derived aromatic compounds under moderate conditions |
title | Efficient O-demethylation of lignin-derived aromatic compounds under moderate conditions |
title_full | Efficient O-demethylation of lignin-derived aromatic compounds under moderate conditions |
title_fullStr | Efficient O-demethylation of lignin-derived aromatic compounds under moderate conditions |
title_full_unstemmed | Efficient O-demethylation of lignin-derived aromatic compounds under moderate conditions |
title_short | Efficient O-demethylation of lignin-derived aromatic compounds under moderate conditions |
title_sort | efficient o-demethylation of lignin-derived aromatic compounds under moderate conditions |
topic | Chemistry |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9936356/ https://www.ncbi.nlm.nih.gov/pubmed/36816077 http://dx.doi.org/10.1039/d3ra00245d |
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