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.

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Bamboo was hydrothermally torrefied in hydrochloric acid solution assisted by microwave heating at 180°C for 5−30 min. For bamboo torrefied in water, the yield of the torrefied bamboo decreased slightly from 96.15% to 85.83% and the hemicellulose content decreased from 31.78% to 25.71% with increased torrefaction severity from 3.27 to 3.89. Whereas for bamboo torrefaction in acid solutions, the yield of the torrefied bamboo was below 51% and hemicellulose was completely removed as evidenced by the fact that the solid residue contained no hemicellulose. The carbon content of bamboo was 48.82% and it increased slightly after torrefaction in water. It raised largely up to 67.03% under torrefaction with 0.4 M HCl solution at 180°C for 30 min. The atomic H/C and O/C ratios of bamboo were 1.479 and 0.694, and as bamboo was wet torrefied, they were in the range of 0.891−1.454 and 0.313−0.676, respectively. The higher heating value (HHV) of the torrefied bamboo increased by 45.20% after torrefaction at 0.2 M HCl for 30 min, which (24.86 MJ kg −1 ) was higher than that of Converse School-Sub C coal (21.67 MJ kg −1 ) and comparable with that of German Braunkohole lignite (25.10 MJ kg −1 ). In addition, the structural modifications of bamboo during the torrefaction process were investigated by chemical component and elemental analyses, CP/MAS 13 C NMR, FTIR, XRD complemented with TG/DTA.

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