Co(salen) supported on graphene oxide for oxidation of lignin

Co(salen) was supported on graphene oxide (GO) (Co‐GO) by covalently grafting. Spectroscopy analyses confirmed its successful synthesis. Co‐GO demonstrated a high activity in the cleavage of βO4 linkage in lignin model compounds. The catalyst was also effective in depolymerizing an organosolv lignin polymer. The polymer residues were separated, and extensively analyzed by FTIR and NMR in order to understand the various structural changes of the polymer occurring versus catalyst. In catalytic oxidation, the βO4 ether linkages were cleaved and the side‐chains were oxidized occurring in the polymer. The polymer was thus converted into smaller monomers called degradation products which were detected by GC‐MS. The evolution of the polymer found that Co‐GO exhibited a significant catalytic effect as compared with Co‐NaY, Co‐MCM‐48, Co‐SSZ‐13.