A DFT Study of Oxidative Lignin β-O-4 Bond Cleavage by Transition-Metal Catalysis
- 1Independent Researcher
- 2Department of Chemistry
- 3Stanford Online High School
Abstract
Biomass is the only viable source of renewable terrestrial carbon. Lignin, a rigid structure of biomass, has been investigated for its difficulty to depolymerize. β-O-4 linkages, which account for 50-60% of all inter-unit bonds, are the primary targets for breaking down the polymer to derive aromatic compounds. Although transition-metal-assisted oxidative cleavage has been identified as a promising method, the conventionally used 4d and 5d transition metals are scarce and expensive, limiting industrial scalability. This study evaluates the efficiency of cost-effective and earth-abundant transition metals Cu(II), Mn(II), Ti(II), and V(II) for the oxidative cleavage of the β-O-4 bond. Using the hybrid density functional B3LYP and wave function CCSD (T) functionals, geometry optimizations for the adducts, transition states, and intermediate complexes were conducted on methoxyethane as a simplified model dimer. Our results identify vanadium as the most promising catalyst kinetically, with a Boltzmann population of ~100%, and copper as the most promising catalyst thermodynamically, with a Boltzmann population of 99.69%. Additional verification using the actual β-O-4 model compound, guaiacylglycerol-β-guaiacyl ether, showed that both V and Cu stretched the target bond to >2.5 Å, exceeding the C–O bond dissociation threshold (1.7–1.8 Å). Given their strong performance as homogeneous catalysts, vanadium and copper show promise for incorporation into heterogeneous catalyst architectures to enable industrial-scale biomass conversion for applications in sustainable materials and biofuels.
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BibTeX
@misc{shen2026study,
title = {{A DFT Study of Oxidative Lignin β-O-4 Bond Cleavage by Transition-Metal Catalysis}},
author = {Ellie Shen and Nick DeMello},
howpublished = {ChemRxiv},
year = {2026},
month = sep,
doi = {10.26434/chemrxiv.15008291/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008291/v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - A DFT Study of Oxidative Lignin β-O-4 Bond Cleavage by Transition-Metal Catalysis
AU - Ellie Shen
AU - Nick DeMello
PY - 2026
DA - 2026/09/04
PB - ChemRxiv
DO - 10.26434/chemrxiv.15008291/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008291/v1
AB - Biomass is the only viable source of renewable terrestrial carbon. Lignin, a rigid structure of biomass, has been investigated for its difficulty to depolymerize. β-O-4 linkages, which account for 50-60% of all inter-unit bonds, are the primary targets for breaking down the polymer to derive aromatic compounds. Although transition-metal-assisted oxidative cleavage has been identified as a promising method, the conventionally used 4d and 5d transition metals are scarce and expensive, limiting industrial scalability. This study evaluates the efficiency of cost-effective and earth-abundant transition metals Cu(II), Mn(II), Ti(II), and V(II) for the oxidative cleavage of the β-O-4 bond. Using the hybrid density functional B3LYP and wave function CCSD (T) functionals, geometry optimizations for the adducts, transition states, and intermediate complexes were conducted on methoxyethane as a simplified model dimer. Our results identify vanadium as the most promising catalyst kinetically, with a Boltzmann population of ~100%, and copper as the most promising catalyst thermodynamically, with a Boltzmann population of 99.69%. Additional verification using the actual β-O-4 model compound, guaiacylglycerol-β-guaiacyl ether, showed that both V and Cu stretched the target bond to >2.5 Å, exceeding the C–O bond dissociation threshold (1.7–1.8 Å). Given their strong performance as homogeneous catalysts, vanadium and copper show promise for incorporation into heterogeneous catalyst architectures to enable industrial-scale biomass conversion for applications in sustainable materials and biofuels.
ER -