Changzhi Li
Dalian Institute of Chemical Physics - CAS China
Posters & Accepted Abstracts: Trends in Green chem
The development of efficient catalytic conversion of lignin into aromatic chemicals remains an important challenge in catalysis due to the amorphous carbon-based inactive property and highly heterogeneous nature of lignin. Potential strategies for the production of aromatics from lignin need to address the issues of lignin solubility as well as of the selective cleavage of the aryl ether bonds. In this lecture, we will discuss our progress in catalytic lignin valorization relating to aforementioned two aspects. In the first part, we will report the selective cleavage of aryl ether in lignin to afford monophenols over tungsten carbide (W2C) catalysts. The activation mechanisms of different aryl ether bonds over W2C are deeply explored. On the other hand, synergistic effect between W2C and a second metal, the effect of the monomer structure on the catalytic performance, and the catalyst stability under liquid phase conditions will be discussed as well. In the second part, selective cleavage of lignin to aromatic compounds catalyzed by methyltrioxorhenium (MTO) without any oxidant (e.g. H2O2) and reducing agent (e.g. H2) is proposed. The introduction of ionic liquids supplies a homogeneous platform which allows the process conducting under mild condition. Microwave irradiation could accelerate the reaction rate and significantly increase the activity. Under optimized conditions, a series of lignin �²-O-4 model compounds could afford guaiacol as the primary product with the yields higher than 67%. The possible mechanisms for degradation of lignin is proposed based on IR spectroscopy and NMR results.
Email: licz@dicp.ac.cn
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