Self-Hydrogen Supplied Catalytic Fractionation of Raw Biomass into Lignin-Derived Phenolic Monomers and Cellulose-Rich Pulps

Lignocellulosic biomass is one of the most well-studiedand promisinggreen carbon sources. The fullest utilization of lignocellulosic biomassin hydrogen-free and mild conditions to produce phenolic monomerswhile preserving cellulose-rich pulps is challenging and has far-reachingsignificance. Here, we report an innovative strategy to convert lignocellulosicbiomass into lignin oils and cellulose-rich pulps without exogenoushydrogen under mild conditions over a Pt/NiAl2O4 catalyst. In this process, the structural hydrogens in hemicelluloseacted as a hydrogen source to realize the fractionation and depolymerizationof lignin into phenolic monomers while keeping the cellulose intact,which is named self-hydrogen supplied catalytic fractionation (SCF).By using water as a solvent, the theoretical yield of phenolic monomers(46.6 wt %, with propyl(ethyl) end-chained syringol and guaiacol asmain products) is achieved at 140 & DEG;C for 24 h, with 90% celluloseintact in birch sawdust. This H-2-free process can be extendedto other biomass (hardwood, softwood, and grass) and can be scaledup. The Pt/NiAl2O4 catalyst also shows goodstability in recycling as well as regeneration treatment. This workprovides a new strategy to achieve high utilization of lignocellulosicbiomass for sustainable biorefinery by using water as a solvent withoutexogenous hydrogen under mild conditions.