The role of hydrogen in lignin pyrolysis: A density functional theory and reactive force field molecular dynamic study on a model compound

LJ Yin and HY Wang and T Li and H Xian and WH Xu and MY Feng and GQ Luo and KG Wang, FUEL, 386, 134258 (2025).

DOI: 10.1016/j.fuel.2024.134258

Products from lignin pyrolysis have low yield and poor selectivity, which restricted the production of chemicals and fuels. Recently, to achieve improved conversion and utilization of lignin, hydrogen donors have been introduced into the pyrolysis system of lignin. However, the structural evolution of intermediates and the role of hydrogen during lignin hydropyrolysis remains to be explored. In this study, the mechanisms of 4-methylguaiacol under hydrogen and helium conditions were analyzed by ReaxFF MD method and DFT calculations. From the results, it was found that hydrogen radicals were generated through hydrogen extraction reactions. Moreover, hydrogen radicals affected the pyrolysis by coupling with phenolic hydroxyl groups, aromatic methoxy groups, para-methyl groups of phenolic hydroxyl groups and carbon atoms on the benzene rings. It could stabilize the intermediates and inhibit the secondary polymerization reactions. It was found that the paths of the formation of primary products in hydrogen atmosphere were mainly triggered by hydrogen radicals. The influence of hydrogen on the pyrolysis mechanism of lignin model compound was revealed from the molecular level.

Return to Publications page