One-Pot Degradation of Cellulose into Furfural Compounds in Hot Compressed Steam with Dihydric Phosphates

Direct conversion of cellulose into furfural compounds (5-hydroxymethylfurfural and furfural) in hot compressed steam with the aid of phosphates was studied under temperatures of 250–330 °C and pressures of 0.5–3.5 MPa. The water in the steam could be adsorbed by cellulose to form water molecule layers, which could hydrolyze cellulose. Basic Na₂HPO₄ was found to be favorable for fragment product formation through hydrolysis of cellulose followed by retro-aldol condensation of saccharide, while the acidic dihydric phosphates (LiH₂PO₄, NaH₂PO₄, and Ca­(H₂PO₄)₂) were favorable for furfural compound formation through the hydrolysis–dehydration process. A total furfural compound yield of 34% was obtained under optimal conditions with the aid of NaH₂PO₄, accompanied by 16% solid residue formation. The solid residue containing dihydric phosphates could be used as phosphatic fertilizer

Production of C₅/C₆ Sugar Alcohols by Hydrolytic Hydrogenation of Raw Lignocellulosic Biomass over Zr Based Solid Acids Combined with Ru/C

Producing chemicals from lignocellulosic biomass is important in view of the huge availability of biomass and positive environmental significance by reducing carbon emission due to fast carbon cycle during biomass growth and applications. Here, we prepared zirconium based solid acids for hydrolytic hydrogenation of raw lignocelluloses to coproduce C₅/C₆ sugar alcohols (the important platform for downstream chemicals and fuel production) as combined with commercial Ru/C. Among these solid acids, the amorphous zirconium phosphate (ZrP) presented the largest acidic sites, with medium and strong acidity as the majority, showing the highest goal sugar alcohols yield of 70% at optimal reaction conditions. During pennisetum transformation, this combined catalyst was reusable despite the activity of the second run being lower than the initial one, and the activity could be recovered by recalcination of spent ZrP. The primary structure of surviving lignin remained after cellulose and hemicellulose were converted, showing the significance for fractional biomass applications if considering the further transformation of lignin