β-O-4 Bond Cleavage Mechanism for Lignin Model Compounds over Pd Catalysts Identified by Combination of First-Principles Calculations and Experiments

Journal Article · Wed Jul 20 00:00:00 EDT 2016 · ACS Catalysis

DOI:https://doi.org/10.1021/acscatal.6b00502· OSTI ID:1656908

Lu, Jianmin ^[1]; Wang, Min ^[1]; Zhang, Xiaochen ^[1]; Heyden, Andreas ^[2]; Wang, Feng ^[1]

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1. Chinese Academy of Sciences (CAS), Dalian (China)
2. Univ. of South Carolina, Columbia, SC (United States)

Lignin in lignocellulosic biomass is the only renewable source for aromatic compounds, and effective valorization of lignin remains a significant challenge in biomass conversion processes. We have performed density functional theory calculations and experiments to investigate the cleavage mechanism of the C–O ether bond in the lignin model compound 2-phenoxy-1-phenylethanol with a β-O-4 linkage over a Pd(111) catalyst surface model. We propose the favorable reaction pathway to proceed as follows: the dilignol reactant gets dehydrogenated first on the α-carbon and then on the -OH group to generate its corresponding ketone 2-phenoxy-1-phenylethanone; the ketone continues to get dehydrogenated on the β-carbon by first a equilibrated keto–enol tautomerization to its enol form and then -OH dehydrogenation; finally, the C–O ether bond cleavage happens afterward, leading to one-aromatic-ring surface intermediates followed by hydrogenation to yield acetophenone and phenol.

• Research Organization: Univ. of South Carolina, Columbia, SC (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: SC0007167
• OSTI ID: 1656908
• Journal Information: ACS Catalysis, Vol. 6, Issue 8; ISSN 2155-5435
• Publisher: American Chemical Society (ACS)
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
biomass
lignin
lignin model
β-O-4 linkage
density functional theory
palladium
Pd(111)