Biphasic Solar Reforming of Lignin to Aromatics and CO for In Situ Carbonylation of Organics

Lignin is a large-scale, renewable carbon source that remains underutilized due to its complex polymeric structure. Photocatalytic conversion of lignin promises selective bond cleavage to yield functionalized products but is hindered by its strong light absorption. Herein, we report a biphasic photocatalytic system that avoids light competition and enables the generation of both CO and functionalized aromatics from Kraft lignin under visible light at ambient temperature and pressure. This system uses water-dispersed CdS quantum dots to photocatalyze the conversion of Kraft lignin's aldehyde and hydroxyl groups to CO via a decarbonylation mechanism. The biphasic system enables this biomass-derived CO to be used in situ for aminocarbonylation. Concurrent cleavage of the β-O-4 bonds in Kraft lignin releases functionalized aromatic products with 81% yield. This work demonstrates the simultaneous light-driven production of sustainable aromatics and one-pot utilization of lignin for carbonylation of organics via cascade reactions.