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Oxidative Depolymerization of Hardwood Lignin to High-Value Aromatics : Optimization by Response Surface Methodology and DFT Study of the Monomers

Ajakaiye Jensen, Lucy I. LU ; El Manira, Lina ; Bekirovska, Selda LU orcid ; Alkhater, Mohammed F. ; Charmillot, Justine ; Hulteberg, Christian P. LU orcid and Abdelaziz, Omar Y. LU (2025) In Topics in Catalysis
Abstract

Beech-wood lignin, derived from the wood of beech trees (genus Fagus), is a lignin-rich biomass with significant potential for valorization. Beech forests are prevalent in temperate regions worldwide, and beech wood possesses desirable properties for various applications, including the construction industry, furniture-making, and pulp production. The oxidative depolymerization of hardwood lignin is a sustainable approach to converting complex lignin structures into high-value aromatic compounds. In this study, the depolymerization of hardwood lignin was optimized using a Box-Behnken design (BBD) quadratic regression model to maximize monomer yields. The model demonstrated high predictive accuracy, with significant alignment between... (More)

Beech-wood lignin, derived from the wood of beech trees (genus Fagus), is a lignin-rich biomass with significant potential for valorization. Beech forests are prevalent in temperate regions worldwide, and beech wood possesses desirable properties for various applications, including the construction industry, furniture-making, and pulp production. The oxidative depolymerization of hardwood lignin is a sustainable approach to converting complex lignin structures into high-value aromatic compounds. In this study, the depolymerization of hardwood lignin was optimized using a Box-Behnken design (BBD) quadratic regression model to maximize monomer yields. The model demonstrated high predictive accuracy, with significant alignment between predicted and actual results, indicating its reliability in optimizing reaction conditions. Key operating parameters – temperature, pressure, and reaction time—were systematically varied, and the optimal conditions for monomer yield were found to be 191 °C, 5 bar O2 pressure, and 25 min. Under these conditions, the primary monomers obtained included syringaldehyde (5.78 wt%) and vanillin (2.31 wt%), along with smaller quantities of acetovanillone, acetosyringone, syringol, and guaiacol. The reducing ability of the resulting monomers was investigated using density functional theory calculations, where electron, hydrogen-atom, and hydride donation ability were determined. Finally, size-exclusion chromatography confirmed the effective breakdown of lignin, showing distinct differences between blank and oxidized samples. This study highlights the effectiveness of oxidative depolymerization under controlled conditions for converting hardwood lignin into valuable aromatic compounds, with the BBD model playing a crucial role in optimizing the process for efficient lignin valorization.

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organization
publishing date
type
Contribution to journal
publication status
epub
subject
keywords
Aromatic chemicals, Beech-wood lignin, Density functional theory, Lignin depolymerization, Response surface methodology, Sustainable resources
in
Topics in Catalysis
publisher
Springer
external identifiers
  • scopus:105003562978
ISSN
1022-5528
DOI
10.1007/s11244-025-02098-9
language
English
LU publication?
yes
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Publisher Copyright: © The Author(s) 2025.
id
daf35d18-ba63-4238-b010-ac58e56056ad
date added to LUP
2025-05-12 14:52:15
date last changed
2025-05-16 13:07:13
@article{daf35d18-ba63-4238-b010-ac58e56056ad,
  abstract     = {{<p>Beech-wood lignin, derived from the wood of beech trees (genus Fagus), is a lignin-rich biomass with significant potential for valorization. Beech forests are prevalent in temperate regions worldwide, and beech wood possesses desirable properties for various applications, including the construction industry, furniture-making, and pulp production. The oxidative depolymerization of hardwood lignin is a sustainable approach to converting complex lignin structures into high-value aromatic compounds. In this study, the depolymerization of hardwood lignin was optimized using a Box-Behnken design (BBD) quadratic regression model to maximize monomer yields. The model demonstrated high predictive accuracy, with significant alignment between predicted and actual results, indicating its reliability in optimizing reaction conditions. Key operating parameters – temperature, pressure, and reaction time—were systematically varied, and the optimal conditions for monomer yield were found to be 191 °C, 5 bar O<sub>2</sub> pressure, and 25 min. Under these conditions, the primary monomers obtained included syringaldehyde (5.78 wt%) and vanillin (2.31 wt%), along with smaller quantities of acetovanillone, acetosyringone, syringol, and guaiacol. The reducing ability of the resulting monomers was investigated using density functional theory calculations, where electron, hydrogen-atom, and hydride donation ability were determined. Finally, size-exclusion chromatography confirmed the effective breakdown of lignin, showing distinct differences between blank and oxidized samples. This study highlights the effectiveness of oxidative depolymerization under controlled conditions for converting hardwood lignin into valuable aromatic compounds, with the BBD model playing a crucial role in optimizing the process for efficient lignin valorization.</p>}},
  author       = {{Ajakaiye Jensen, Lucy I. and El Manira, Lina and Bekirovska, Selda and Alkhater, Mohammed F. and Charmillot, Justine and Hulteberg, Christian P. and Abdelaziz, Omar Y.}},
  issn         = {{1022-5528}},
  keywords     = {{Aromatic chemicals; Beech-wood lignin; Density functional theory; Lignin depolymerization; Response surface methodology; Sustainable resources}},
  language     = {{eng}},
  publisher    = {{Springer}},
  series       = {{Topics in Catalysis}},
  title        = {{Oxidative Depolymerization of Hardwood Lignin to High-Value Aromatics : Optimization by Response Surface Methodology and DFT Study of the Monomers}},
  url          = {{http://dx.doi.org/10.1007/s11244-025-02098-9}},
  doi          = {{10.1007/s11244-025-02098-9}},
  year         = {{2025}},
}