Recently, the work of Combustion and Energy Research Group entitled "Evidence of phenolic pool as a key intermediate for zeolite-catalyzed lignin pyrolysis" was published in Angewandte Chemie International Edition, a top journal in the field of chemical engineering. The first author of this paper is Chunjiang Liu (PhD graduate), and the corresponding authors are Prof. Zhongyue Zhou (Shanghai Jiao Tong University) and Prof. Liangyuan Jia (Hefei University of Technology).

Phenolic pool is considered to be an important intermediate during catalytic conversion of biomass. However, no direct evidence has been reported on its full picture at the molecular level, due to the huge challenges in probing reactive and low volatile phenolic oligomers with the state-of-the-art technologies. This work presents an on-line full-spectrum measurement of heavy phenolic oligomers during zeolite-catalyzed pyrolysis of lignin. To the best of our knowledge, this is the first direct “vision” of phenolic pool at the molecular level. Investigations on model compounds through in situ APPI HRMS and 2D solid-state NMR reveal that the formation of these phenolic pool-related oligomers originates from repolymerization of monomeric units and acts as a key mechanistic step for aromatic and coke formation in catalytic conversion of lignin over HZSM-5. This work also demonstrate the ubiquity of this concept in other zeolites. It is anticipated that this insight into the formation of the phenolic pool would contribute to a fundamental understanding of the catalyst deactivation mechanism. Furthermore, the evidence of phenolic pool as an important intermediate allows envisaging of more efficient approaches to catalyst selection and optimization by mediating intermediates, for example, introducing a supported active sites with confined space to control oligomers formation and to improve the catalyst selectivity towards valuable products.

This research was funded by the Key Research and Development Program of China and the National Natural Science Foundation of China.

Link to the paper: https://www.onlinelibrary.wiley.com/doi/10.1002/anie.202011937