Demethylation of a methoxy group to inhibit repolymerization during alkaline lignin pyrolysis

Authors：Ma, Hao; Li, Tengfei; Wu, Shubin^*; Zhang, Xiaohua

Source：Fuel, 2021, 286: 119394.

DOI：10.1016/j.fuel.2020.119394

• Lignin
• Methoxy group
• Repolymerization
• Pyrolysis
• Demethylation

The methoxy group in lignin was demethylated using iodocyclohexane; then, lignins with different methoxy group contents and six model compounds were pyrolyzed at 600 degrees C to investigate the role of methoxy groups during lignin pyrolysis. The results indicated that iodocyclohexane modification not only promotes methoxy demethylation but also causes side chain ether bond breakage. Demethylation of the methoxy group could inhibit the repolymerization reaction and reduce the activation energy during later lignin pyrolysis, and could also promote the homolysis of Ar-C alpha. The pyrolysis experiments of the model compounds showed that the methoxy group is not an essential factor for the formation of pyrolytic char; however, it could promote the repolymerization reaction by intramolecular interaction with phenolic hydroxyl.

• Institution
  江西农业大学