Total chemocatalytic cascade conversion of lignocellulosic biomass into biochemicals

Because of its complexity, selective conversion of lignocellulosic biomass into platform chemicals presents significant challenges. Herein, we converted birch wood into high-yield lignin-derived phenolic monomers and dimers and holocellulose-derived polyols and monocarboxylic acids via a two-step cascade reaction using 0.1 wt% Pd on N-doped carbon (Pd_0.1/CN_x) and passivated alumina-coated Ni on activated carbon (Ni₂ @Al₂O₃/AC) catalysts. The catalytic fractionation of birch sawdust using Pd_0.1/CN_x produced 11.1 wt% monomers, 5.6% dimers, and 63.4 wt% pulp-rich solid (PRS) based on feed weight. The subsequent conversion of PRS over passivated Ni₂ @Al₂O₃/AC produced 21.6 wt% C₂–C₆ polyols and 7.9 wt% monocarboxylic acids. After the whole biomass conversion reaction, the Pd_0.1/CN_x and Ni₂ @Al₂O₃/AC catalysts were separated using their different magnetic responses and reused three times without activity loss. The structure–performance relationships of the Pd_0.1/CN_x catalysts synthesized using different methods and effect of passivation on the performance of the Ni₂ @Al₂O₃/AC catalyst were analyzed.