Evidence of a Phenolic Pool as a Key Intermediate for Zeolite-Catalyzed Lignin Pyrolysis

The phenolic pool is considered to be an important intermediate during the catalytic conversion of biomass. However, no direct evidence has been reported on its full picture on a molecular level due to the huge challenges in probing the reactive and lowly volatile phenolic oligomers with state-of-the-art technologies. Herein, we report the online detection and structural identification of a phenolic pool by utilizing in-situ atmospheric-pressure photoionization mass spectrometry, demonstrating that the phenolic pool is formed through repolymerization of monomers with an equidistant group pattern and acts as a key mechanistic step for both valuable aromatic products and undesired coke. The exploration of the real reactive species is also of great importance for the rational design and synthesis of advanced catalysts with high activity.

Automated summary

This study utilized in-situ atmospheric-pressure photoionization mass spectrometry to detect and identify the structure of the phenolic pool, revealing it as a key mechanistic step formed through repolymerization of monomers, which can generate valuable aromatic products and undesired coke. Exploration of the real reactive species is important for the rational design and synthesis of advanced catalysts with high activity.