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Acid-catalysed α-O-4 aryl-ether bond cleavage in methanol/(aqueous) ethanol: understanding depolymerisation of a lignin model compound during organosolv pretreatment

The selective lignin conversion into bio-based organic mono-aromatics is a major general challenge due to complex structure itself/additional macromolecule modifications, caused by the cleavage of the ether chemical bonds during the lignocellulosic biomass organosolv pulping in acidified aqueous eth...

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Autores principales: Jasiukaitytė-Grojzdek, Edita, Huš, Matej, Grilc, Miha, Likozar, Blaž
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7338503/
https://www.ncbi.nlm.nih.gov/pubmed/32632147
http://dx.doi.org/10.1038/s41598-020-67787-9
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author Jasiukaitytė-Grojzdek, Edita
Huš, Matej
Grilc, Miha
Likozar, Blaž
author_facet Jasiukaitytė-Grojzdek, Edita
Huš, Matej
Grilc, Miha
Likozar, Blaž
author_sort Jasiukaitytė-Grojzdek, Edita
collection PubMed
description The selective lignin conversion into bio-based organic mono-aromatics is a major general challenge due to complex structure itself/additional macromolecule modifications, caused by the cleavage of the ether chemical bonds during the lignocellulosic biomass organosolv pulping in acidified aqueous ethanol. Herein, the acido-lysis of connected benzyl phenyl (BPE), being a representative model compound with α-O-4 linkage, was investigated in methanol, EtOH and 75 vol% EtOH/water mixture solutions, progressing each time with protonating sulfuric acid. The effect of the physical solvent properties, acidity of the reaction process media and temperature on rate was determined. Experiments suggested BPE following S(N)1 mechanism due to the formation of a stable primary carbocation/polarity. The product species distribution in non-aqueous functional alcohols was strongly affected. The addition of H(2)O was advantageous, especially for alkoxylation. Yield was reduced by a factor of 3, consequently preserving reactive hydroxyl group. Quantitative experimental results indicated key performance parameters to achieve optimum. Organosolv lignins were further isolated under significantly moderate conditions. Consecutive structural differences observed supported findings, obtained when using BPE. H(2)O presence was again found to grant a higher measured –OH content. Mechanistic pathway analysis thus represents the first step when continuing to kinetics, structure–activity relationships or bio-refining industrial resources.
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spelling pubmed-73385032020-07-09 Acid-catalysed α-O-4 aryl-ether bond cleavage in methanol/(aqueous) ethanol: understanding depolymerisation of a lignin model compound during organosolv pretreatment Jasiukaitytė-Grojzdek, Edita Huš, Matej Grilc, Miha Likozar, Blaž Sci Rep Article The selective lignin conversion into bio-based organic mono-aromatics is a major general challenge due to complex structure itself/additional macromolecule modifications, caused by the cleavage of the ether chemical bonds during the lignocellulosic biomass organosolv pulping in acidified aqueous ethanol. Herein, the acido-lysis of connected benzyl phenyl (BPE), being a representative model compound with α-O-4 linkage, was investigated in methanol, EtOH and 75 vol% EtOH/water mixture solutions, progressing each time with protonating sulfuric acid. The effect of the physical solvent properties, acidity of the reaction process media and temperature on rate was determined. Experiments suggested BPE following S(N)1 mechanism due to the formation of a stable primary carbocation/polarity. The product species distribution in non-aqueous functional alcohols was strongly affected. The addition of H(2)O was advantageous, especially for alkoxylation. Yield was reduced by a factor of 3, consequently preserving reactive hydroxyl group. Quantitative experimental results indicated key performance parameters to achieve optimum. Organosolv lignins were further isolated under significantly moderate conditions. Consecutive structural differences observed supported findings, obtained when using BPE. H(2)O presence was again found to grant a higher measured –OH content. Mechanistic pathway analysis thus represents the first step when continuing to kinetics, structure–activity relationships or bio-refining industrial resources. Nature Publishing Group UK 2020-07-06 /pmc/articles/PMC7338503/ /pubmed/32632147 http://dx.doi.org/10.1038/s41598-020-67787-9 Text en © The Author(s) 2020 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
spellingShingle Article
Jasiukaitytė-Grojzdek, Edita
Huš, Matej
Grilc, Miha
Likozar, Blaž
Acid-catalysed α-O-4 aryl-ether bond cleavage in methanol/(aqueous) ethanol: understanding depolymerisation of a lignin model compound during organosolv pretreatment
title Acid-catalysed α-O-4 aryl-ether bond cleavage in methanol/(aqueous) ethanol: understanding depolymerisation of a lignin model compound during organosolv pretreatment
title_full Acid-catalysed α-O-4 aryl-ether bond cleavage in methanol/(aqueous) ethanol: understanding depolymerisation of a lignin model compound during organosolv pretreatment
title_fullStr Acid-catalysed α-O-4 aryl-ether bond cleavage in methanol/(aqueous) ethanol: understanding depolymerisation of a lignin model compound during organosolv pretreatment
title_full_unstemmed Acid-catalysed α-O-4 aryl-ether bond cleavage in methanol/(aqueous) ethanol: understanding depolymerisation of a lignin model compound during organosolv pretreatment
title_short Acid-catalysed α-O-4 aryl-ether bond cleavage in methanol/(aqueous) ethanol: understanding depolymerisation of a lignin model compound during organosolv pretreatment
title_sort acid-catalysed α-o-4 aryl-ether bond cleavage in methanol/(aqueous) ethanol: understanding depolymerisation of a lignin model compound during organosolv pretreatment
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7338503/
https://www.ncbi.nlm.nih.gov/pubmed/32632147
http://dx.doi.org/10.1038/s41598-020-67787-9
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