Preventing Hemicellulose Degradation: Toward Selective Production of Aromatic Amines

The lignin-first biorefinery, while successful in extracting high-value lignin, faces a critical bottleneck: the uncontrolled degradation of hemicellulose into complex mixtures during processing. This poorly valorized pathway severely limits the full potential of lignocellulosic biomass. Breaking from convention, we introduce a one-pot formic acid-aniline system that simultaneously extracts and converts hemicellulose, directly targeting this challenge. In this system, aniline acts as a strategic nucleophilic trap, capturing key furanic intermediates and decisively terminating the degradation cascade. The result is a dramatic shift from complex mixtures to selective synthesis: with the formic acid-aniline system, almost all the hemicelluloses have been converted into single aromatic amine compounds, including N-phenyltetrahydrofuran-2-carboxamide (PAMTHF) and (Z)-5-((phenylamino)-methylene)-tetrahydrofuran-3-ol (PTHF-CA). By adjusting the reaction system, 95.20% of hemicellulose derivatives could be remined into the form of PAMTHF. Remarkably, the resulting liquor contains no detectable sugar residues or conventional derivatives, bypassing costly separation steps and opening a direct route to high-value chemicals. This work fundamentally reimagines hemicellulose valorization, transforming a longstanding challenge into a streamlined and industrially viable process.