Partial depolymerization of enzymolysis lignin via mild hydrogenolysis over Raney Nickel

•Partial depolymerization of enzymolysis lignin was performed via mild hydrogenolysis.•High yields of depolymerized lignin were obtained under optimal conditions.•Depolymerized lignins were low molecular weight oligomers with increased OH values.•31P NMR was used to characterize the partial depolymerized lignins.•The depolymerized enzymolysis lignin exhibited good solubility in organic solvents.

In this work, partial depolymerization of enzymolysis lignin collected from a woody biomass-to-ethanol process was studied via mild hydrogenolysis under the catalysis of Raney Ni. The depolymerized lignin products were low molecular weight oligomers with increased hydroxyl values. The solvent selected, use of base and various reaction parameters were all found to influence yield of depolymerization, the molecular weight and hydroxyl value of the hydrogenated product. The depolymerized lignins displayed greatly enhanced solubility in organic solvents, and therefore would have great potential to be used as feedstock for many valuable thermosetting polymer applications.

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