Structural characterization and pyrolysis mechanism of γ-O-4 in lignin unraveled by density functional theory simulation

Lignin is an important constituent of biomass, and fully revealing the pyrolysis mechanism of lignin improves its pyrolysis process, thus improving the pyrolysis efficiency of biomass. The gamma-O-4 structure is the connection structure of lignin, which can accelerate the rearrangement of co-gasification oils. Combining the density functional theory (DFT) with wave function analysis, this study reveals the pyrolysis mechanism of a gamma-O-4 lignin dimer model compound, calculating the free energy barriers and reaction rates, and obtained six reaction pathways. Also, this paper analyzes the pyrolysis characteristics of the structure. The results fill in the gap of gamma-O4 reaction mechanisms lignin, explicating the mechanisms and characteristics of lignin pyrolysis products, and further perfecting the theoretical foundation for the high-value utilization of biomass.