Vapor-Phase Hydrodeoxygenation of Guaiacol to Aromatics over Pt/HBeta: Identification of the Role of Acid Sites and Metal Sites on the Reaction Pathway

Journal Article · Mon Feb 05 00:00:00 EST 2018 · ChemCatChem

DOI:https://doi.org/10.1002/cctc.201701413· OSTI ID:1427913

Nie, Lei ^[1]; Peng, Bo ^[2]; Zhu, Xinli  ^[3]

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1. Collaborative Innovation Center of Chemical Science and Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 P.R. China; Institute for Integrated Catalysis, Pacific Northwest National Laboratory, P.O. Box 999 Richland WA 99352 USA
2. Institute for Integrated Catalysis, Pacific Northwest National Laboratory, P.O. Box 999 Richland WA 99352 USA
3. Collaborative Innovation Center of Chemical Science and Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 P.R. China

Hydrodeoxygenation of guaiacol, a phenolic compound derived from lignin fraction of biomass, over a Pt/HBeta catalyst at 350 °C and atmospheric pressure produces benzene, toluene, xylenes, and C9+ aromatics with yield of 42%, 29%, 12%, and 5%, respectively. Reaction pathways for conversion of two functional groups (hydroxyl and methoxyl) over the bifunctional catalyst were studied. Both guaiacol and intermediate products (catechol and cyclopentanone) were fed onto zeolite HBeta and Pt/SiO2 to identify the individual role of acid site and metal site. Acid sites (mainly Brønsted acid site, BAS) catalyze transalkylation and dehydroxylation reactions in sequence, producing phenol, cresols and xylenols as the major products at high conversion. Pt sites catalyze demethylation reaction resulting in catechol as the primary product, which can either be deoxygenated to phenol followed by phenol to benzene, or decarbonylated to cyclopentanone and further to butane. The close proximity of Pt and BAS in bifunctional Pt/HBeta enables both transalkylation and deoxygenation reactions with inhibited demethylation and decarbonylation reactions, producing aromatics as major final products with a total yield > 85%. Both activity and stability of bifunctional Pt/HBeta during hydrodeoxygenation of guaiacol is improved compared to HBeta and Pt/SiO2. The addition of water to the feed further improves the activity and stability via hydrolysis of O-CH3 bond of guaiacol on BAS and removing coke around Pt.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1427913
• Report Number(s): PNNL-SA-127490
• Journal Information: ChemCatChem, Vol. 10, Issue 5; ISSN 1867-3880
• Publisher: ChemPubSoc Europe
• Country of Publication: United States
• Language: English