Selective production of phenolic monomers via high efficient lignin depolymerization with a carbon based nickel-iron-molybdenum carbide catalyst under mild conditions.

Lignin is an abundant renewable source of bio-aromatics and its valorization is of great importance. In this work, an efficient non-precious carbon based metal-Mo2C catalytic system for selective production of phenolic monomers (PMs) from organosolv lignin depolymerization is proposed. With the optimized catalyst of Ni-Fe-Mo2C, 89.56% of liquefaction and 35.53% of PMs yields were achieved under 260 ℃ for 4 h with water-methanol (4:1 v/v) solvent. Characterization of the catalysts shows that the induction of Ni-Fe species was favor for the formation of ß-Mo2C, and efficiently promoted the lignin liquefaction. The decoration of Ni/Fe can also change the side chain hydrogenolysis ability of the catalyst and exhibite high yield for 4-ethylphenol (14.77%) production. Methanol, used as co-solvent, was found to play an important role in PMs production and lignin depolymerization. These results demonstrated that the Ni-Fe-Mo2C catalytic system has potential to produce valuable phenolic monomers from lignin under mild conditions.