Mechanism study on pyrolysis interaction between cellulose, hemicellulose, and lignin based on photoionization time-of-flight mass spectrometer (PI-TOF-MS) analysis

It is critical to accurately reveal the interactions between biomass components for the selective preparation and directional exploitation of pyrolysis products. The rapid, simultaneous capture of the full mass spectrum of in-termediates is advantageous for elucidating the interaction mechanism. To depict the real complicated pyrolysis reactions, a simplified coupled cross-pyrolysis process among the biomass components is examined. The inter-action was studied by the examination of offline product distribution, bio-oil, and bio-gas composition, as well as the evolution of pyrolysis intermediates using an online photoionization time-of-flight mass spectrometer (PI-TOF-MS). Results indicate that the interaction only affects product distribution, rather than creating a new pyrolysis reaction pathway. The cracking of glycosidic bonds during low-temperature cellulose depolymerization provides hydrogen donor (H center dot) and hydroxyl donor (OH center dot) for the primary cleavage of hemicellulose and lignin. It increases the ring opening of C5 of hemicellulose and the cleavage of lignin's phenylpropane side chains, pro-moting the production of aliphatic compounds, guaiac-based phenols, and syringe-based phenols. C-O cracking on the side chain of phenylpropane provides donors for the ring opening of cellulose's secondary pyrolysis products, further promoting the production of aliphatic chains. High temperatures hasten the fragmentation of partial aliphatic chains and the demethylation of phenols, providing donors and molecular fragments (methyl and methoxy, etc.) for the aromatization of linear molecules and encouraging the generation of aromatic com-pounds. The study's findings will help to improve knowledge of the biomass pyrolysis interaction and be used as a reference for targeted biomass utilization and the optimization of catalytic pyrolysis strategies.

Automated summary

Accurately revealing the interactions between biomass components is crucial for selectively preparing and exploiting pyrolysis products. Using an online photoionization time-of-flight mass spectrometer (PI-TOF-MS), the study examines a simplified coupled cross-pyrolysis process to depict the real complicated pyrolysis reactions and elucidate the interaction mechanism. Results show that the interaction only affects product distribution and does not create new pyrolysis reaction pathways. The findings contribute to improving knowledge of biomass pyrolysis interaction and can be used as a reference for targeted biomass utilization and catalytic pyrolysis optimization strategies.