Valorization of native birch wood lignin into monomeric phenols over nickel-based catalysts has been studied. High chemoselectivity to aromatic products was achieved by using Ni-based catalysts and common alcohols as solvents. The results show that lignin can be selectively cleaved into propylguaiacol and propylsyringol with total selectivity >90% at a lignin conversion of about 50%. Alcohols, such as methanol, ethanol and ethylene glycol, are suitable solvents for lignin conversion. Analyses with MALDI-TOF and NMR show that birch lignin is first fragmented into smaller lignin species consisting of several benzene rings with a molecular weight of m/z ca. 1100 to ca. 1600 via alcoholysis reaction. The second step involves the hydrogenolysis of the fragments into phenols. The presence of gaseous H₂ has no effect on lignin conversion, indicating that alcohols provide active hydrogen species, which is further confirmed by isotopic tracing experiments. Catalysts are recycled by magnetic separation and can be reused four times without losing activity. The mechanistic insights from this work could be helpful in understanding native lignin conversion and the formation of monomeric phenolics via reductive depolymerization.

The conversion of furfural into cyclopentanone over Ni–Cu bimetallic catalysts was studied under hydrogen atmosphere. Furfuryl alcohol, 4-hydroxy-2-cyclopentenone and 2-cyclopentenone were verified as three key intermediates. Rearrangement of the furan ring was independent of hydrogenation, starting from furfuryl alcohol rather than furfural. The opening and closure of the furan ring were closely related to the attack of a H₂O molecule on the 5-position of furfuryl alcohol. Prior hydrogenation of the aldehyde group accounted for the different reactivity of furfural and furfuryl alcohol. The high selectivity of cyclopentanone was ascribed to the presence of 2-cyclopentenone.

We report a strategy for the catalytic conversion of lignosulfonate into phenols over heterogeneous nickel catalysts. Aryl–alkyl bonds (C–O–C) and hydroxyl groups (–OH) are hydrogenated to phenols and alkanes, respectively, without disturbing the arenes. The catalyst is based on a naturally abundant element, and is recyclable and reusable.

Furan-based copolyesters were synthesized via polytransesterification of 2,5-furandicarboxylic acid (FDCA) with ethylene glycol (EG) and 1,4-butylene glycol (BG). The composition and thermal properties of the obtained copolyesters were characterized in detail by ¹H NMR and elemental analysis, differential scanning calorimeters (DSC) and thermogravimetric analysis (TGA). The ¹H NMR results showed that the ethylene segment content was consistently lower than that of butylene in the obtained copolyesters in comparison with the comonomer feeds. The reactivities of EG and BG with FDCA were intensively investigated. On the basis of kinetic studies, EG was found to be less reactive than BG. The thermal properties of the obtained copolyesters could be adjusted by variation of the EG/BG molar ratios in the copolyesters.