Mechanistic study on the depolymerization of typical lignin-derived oligomers catalyzed by Pd/NbOPO4

●The reaction involved Cα-Cβ, Cβ-Cγ and C-O bonds cleavage and continuous H-transfer processes.●Synergistic effect of Pd and NbOPO4 promoted C-O/C-C bond cleavage in lignin-derived oligomers, affording 4-substituted syringols and 4-ethyl guaiacols.●The most possible pathway for catalytic depolymerization of trimeric oligomer was proposed.