Year: 2026
Type: preprint
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.
Source: ChemRxiv
Authors: Ellie Shen, Nick DeMello
Institution: Stanford University
Language: English
Topic: Lignin and Wood Chemistry
Subfield: Biomedical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7208713274