ao8b00994_si_001.pdf (1.83 MB)
Cobalt-Catalyzed Oxidation of the β‑O‑4 Bond in Lignin and Lignin Model Compounds
journal contribution
posted on 2018-07-30, 18:35 authored by Torsten Rinesch, Carsten BolmIn this work we demonstrate the use
of Co(acac)3 in
combination with N-hydroxyphthalimide as an oxidant
for the selective α-oxidation of the representative β-O-4
linkages in lignin model compounds. The oxidation reaction proceeds
under mild conditions at 80 °C using 1,4-dioxane as the solvent
and an oxygen atmosphere. The prior α-oxidation in the β-O-4
linkage of the lignin polymer is known to result in an easier cleavage
of the adjacent C–O and C–C bonds because of a decrease
in bond stability. Finally, the conditions were successfully transferred
to kraft- and organosolv-lignin samples as proven by 2D-NMR (HSQC)
experiments and gel permeation chromatography measurements.