Iron-induced demethoxylation of lignin as an important source for methanol and its oxidation products in the environment [data]

Lignin, the largest reservoir of aromatic carbon in plants and soils, undergoes well-characterized biological demethylation by fungi and bacteria, and is industrially processed under harsh conditions to generate bio-based aromatics. However, the abiotic fate of lignin-derived methoxy groups under environmentally relevant conditions remains unresolved.

Here, we report an iron-mediated demethoxylation mechanism involving direct aromatic C–O bond cleavage under ambient conditions. Using FeII/FeIII species and H2O2, we demonstrate the efficient release of entire methoxy groups from lignin monomers and methoxyphenols, forming methanol and subsequently formaldehyde. Isotopic labeling unequivocally shows that the complete –OCH3 group is liberated intact.