Abstract
In this work, we developed an approach of one-pot completely catalytic conversion of woody biomass into two value product streams: lignin-derived aromatics (68.54% monomer and 29.65% oligomer yields of lignin) and (semi-)cellulose-derived small molecular alcohols (about 59.60% of biomass mass). These could be afforded by conducting lignocellulose depolymerization over metal-alkaline catalysts in a mixture n-butanol/H2O solvent system at 250 °C and 30 bar H2. In the valorization process, the homogenous mixture of n-butanol-H2O solvents extract and depolymerize both lignin and hemicellulose, while the catalysts and H2 are essential to cleave the inter-/intramolecular linkages of lignocellulose into target products. After the reaction, phase separation of n-butanol and H2O takes place when systematic temperature at room temperature, providing a mild and effective strategy to isolate lignin-derived aromatics (n-butanol phase) from small molecular alcohols/acids (aqueous phase). Ru/C and alkali catalysts are collected by filtration from n-butanol phase and H2O phase, respectively. Meanwhile, the effect of metal-alkali coupled catalysts enables facilitating the cleavage of β-O-4 linkage of lignin and increasing the attainability of (semi-)cellulose-derived oligomers and the small molecular alcohols. This catalytic system provides a versatile valorization approach for biomass catalytic to bio-based chemicals.
Synthesis of structurally diverse 3,4-dihydropyrimidin-2(1H)-ones via sequential Biginelli and Passerini reactions
