The development of a green system to solubilize cellulose from raw biomass is important, yet it is challenging because of the insolubility of cellulose in most solvents. Herein, a green NaCl-H₂O system is developed in which NaCl significantly enhances the dissolution and depolymerisation of cellulose from raw biomass. Nearly all the cellulose in the selected biomass types was dissolved and degraded into oligomers with molecular weights of 200–400 Da under relatively mild conditions. Cl⁻ could interact strongly with the end OH group of the glucose unit in a 1:1 ratio, which resulted in the enhanced breaking of both inter- and intramolecular hydrogen bonds. In particular, the intermolecular hydrogen bond with an FTIR band at approximately =3200 cm⁻¹ was disrupted significantly by Cl⁻. The FTIR band for a hydrogen bond between hemicellulose and lignin might appear at =1636 cm⁻¹, whereas this bond could be almost totally broken under hydrothermal conditions at 220 °C.

The mechanism and enantioselectivity of the asymmetric Baeyer–Villiger oxidation reaction between 4-phenylcyclohexanone and m-chloroperoxobenzoic acid (m-CPBA) catalyzed by Sc^III–N,N′-dioxide complexes were investigated theoretically. The calculations indicated that the first step, corresponding to the addition of m-CPBA to the carbonyl group of 4-phenylcyclohexanone, is the rate-determining step (RDS) for all the pathways studied. The activation barrier of the RDS for the uncatalyzed reaction was predicted to be 189.8 kJ mol⁻¹. The combination of an Sc^III–N,N′-dioxide complex and the m-CBA molecule can construct a bifunctional catalyst in which the Lewis acidic Sc^III center activates the carbonyl group of 4-phenylcyclohexanone while m-CBA transfers a proton, which lowers the activation barrier of the addition step (RDS) to 86.7 kJ mol⁻¹. The repulsion between the m-chlorophenyl group of m-CPBA and the 2,4,6-iPr₃C₆H₂ group of the N,N′-dioxide ligand, as well as the steric hindrance between the phenyl group of 4-phenylcyclohexanone and the amino acid skeleton of the N,N′-dioxide ligand, play important roles in the control of the enantioselectivity.

In this work, a one-pot strategy for directly converting fructose into 2,5-diformylfuran (DFF) over Mo-containing Keggin heteropolyacids (HPAs) in open air is developed. H₃PMo₁₂O₄₀ HPA is found to show high activity and selectivity to the formation of DFF owing to its higher Brønsted acidity and moderate redox potential. The partial substitution of the H⁺ in H₃PMo₁₂O₄₀ with Cs⁺ leads to the heterogenization of the HPA by forming its cesium salts Cs_xH_3−xPMo₁₂ (x=0.5, 1.5, and 2.5). A satisfactory yield of 69.3 % to DFF is obtained over Cs_0.5H_2.5PMo₁₂ polyoxometalate after deliberate optimization of the reaction conditions. The heterogenized polyoxometalate could be recycled and reused without significant loss of catalytic activity for five runs. The produced DFF could be separated from the resulting mixture by an adsorption–desorption method using activated carbon as the adsorbent and furfural as the desorbent. A highest isolated yield of 58.2 % is obtained.

Increased energy consumption and environmental concerns have driven efforts to produce chemicals from renewable biomass with high selectivity. Here, the selective conversion of cellulose in corncob residue, a process waste from the production of xylose, to levulinic acid was carried out using AlCl₃ as catalyst and NaCl as promoter by a hydrothermal method at relatively low temperature. A levulinic acid yield of 46.8 mol % was obtained, and the total selectivity to levulinic acid with formic acid was beyond 90 %. NaCl selectively promoted the dissolution of cellulose from corncob residue, and significantly improved the yield and selectivity to levulinic acid by inhibiting lactic acid formation in the subsequent dehydration process. Owing to the salt effect of NaCl, the obtained levulinic acid could be efficiently extracted to tetrahydrofuran from aqueous solution. The aqueous solution with AlCl₃ and NaCl could be recycled 4 times. Because of the limited conversion of lignin, this process allows for the production of levulinic acid with high selectivity directly from corncob residue in a simple separation process.