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

Hao Zhou; Xiaohui Liu; Yong Guo; Yanqin Wang

doi:10.1021/jacsau.3c00154

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

JACS Au. 2023 Jun 29;3(7):1911-1917. doi: 10.1021/jacsau.3c00154. eCollection 2023 Jul 24.

Authors

Hao Zhou¹, Xiaohui Liu¹, Yong Guo¹, Yanqin Wang¹

Affiliation

¹ Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering Shanghai, Feringa Nobel Prize Scientist Joint Research Center, Research Institute of Industrial Catalysis, School of Chemistry and Molecular Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, P. R. China.

Abstract

Lignocellulosic biomass is one of the most well-studied and promising green carbon sources. The fullest utilization of lignocellulosic biomass in hydrogen-free and mild conditions to produce phenolic monomers while preserving cellulose-rich pulps is challenging and has far-reaching significance. Here, we report an innovative strategy to convert lignocellulosic biomass into lignin oils and cellulose-rich pulps without exogenous hydrogen under mild conditions over a Pt/NiAl₂O₄ catalyst. In this process, the structural hydrogens in hemicellulose acted as a hydrogen source to realize the fractionation and depolymerization of 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 as main products) is achieved at 140 °C for 24 h, with 90% cellulose intact in birch sawdust. This H₂-free process can be extended to other biomass (hardwood, softwood, and grass) and can be scaled up. The Pt/NiAl₂O₄ catalyst also shows good stability in recycling as well as regeneration treatment. This work provides a new strategy to achieve high utilization of lignocellulosic biomass for sustainable biorefinery by using water as a solvent without exogenous hydrogen under mild conditions.