Fragmentation of Woody Lignocellulose into Primary Monolignols and Their Derivatives

Lignin, which is biosynthesized through oxidative radical polymerization from primary monolignols during plant growth, represents the most abundant source of renewable aromatic resources. The search for efficient and selective catalysts for the production of monolignols and their corresponding unsaturated derivatives from the direct depolymerization of lignin is of great interest and importance, as such products are important platform chemicals for the synthesis of natural products, pharmaceuticals, and functional materials. We report herein the first case of a supported molybdenum catalyst that functions as an efficient and selective catalyst for the fragmentation of woody lignocelluloses, leading to monolignols and ethers in high yields with high selectivity. Hydrogenation of the side chain and recondensation were not observed, suggesting that etherification acts as a new stabilization mechanism in the current Mo catalytic system. The (hemi)­cellulose components were well preserved and amenable to valorization via enzymatic hydrolysis and chemocatalytic conversion. This method constitutes an economically responsible pathway for lignin valorization as well as fractionation and sequential utilization of all of the biomass components.