429493 Dehydration Kinetics over Metal-Modified Zeolites: Impact for Biomass Pyrolysis

Tuesday, November 10, 2015: 4:18 PM
257B (Salt Palace Convention Center)
David Robichaud1, Robin Cywar1, Seonah Kim1, Lintao Bu2, Brian Trewyn3, Mengze Xu3, Matt Yung1, Ryan McDonough4 and Mark R. Nimlos1, (1)National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, (2)National Bioenergy Center, National Renewable Energy Lab, Golden, CO, (3)Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, CO, (4)Chemistry, Univeristy of Deleware, DE

Dehydration Kinetics over Metal-Modified Zeolites: Impact for Biomass Pyrolysis

David J. Robichaud, Robin Cywar, Lintao Bu, Seonah Kim, Brian Trewyn, Mengze Xu, Matthew Yung, Ryan McDonough, and Mark Nimlos

Catalytic fast pyrolysis over zeolite catalysts is a promising thermochemical technology to convert biomass to transportation fuels or biomaterials. However, several technical issues continue to impede the implementation of this technology including oil yields, oxygen content, and physiochemical properties. Poor understandings of catalytic reaction kinetics (e.g. dehydration, decarbonylation) continue to hinder progress toward addressing these technical issues. Dehydration over acidic zeolites plays an important role in the deoxygenation and coupling reactions during catalytic fast pyrolysis. We have applied a combined experimental/computational approach to investigate two dehydration-related reactions in an effort to generalized our understanding of this important reaction class: dehydration of alcohols to olefins, and aldol coupling/dehydration reactions of small oxygenates to produce furans. Kinetic reaction mechanisms have been investigated over nascent zeolites (MFI, Beta, MOR) to identify descriptors for catalytic reactivity that can be used to design more effective catalysts. Based on these descriptors, modified zeolites were synthesized with transition metals metals. The resulting Brønsted and Lewis acidity upon zeolite modification is assessed and the consequences for the activation barriers are evaluated. Hybrid QM/MM ONIOM model calculations are performed and compared against experimental results for improved reactivity.

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