Title:

New Heterogeneous Catalysts for Converting Sugars in Aqueous Media

Speaker:

Dr. Mark E. Davis

Affiliation:

California Institute of Technology

When:

Thursday, March 10, 2011 at 11:00:00 AM   Add to Calendar

Where:

Ford Building, Room L1255

Host:

Brenda J. Mattox
brenda@gatech.edu

Abstract

The isomerization of glucose into fructose is a large-scale reaction for the production of high-fructose corn syrup and recently is being considered as an intermediate step in the possible route of biomass to fuels and chemicals. Here, it is shown that a large-pore zeolite that contains tin (Sn-Beta) is able to isomerize blucose to fructose in aqueous media with high activity and selectivity. Specifically, a 10 wt% glucose solution containing a catalytic amount of SN-Beta (1:50 Sn:glucose molar ration) gives product yields of approximately 46% (w/w) glucose, 31% (w/w) fructose, and 9% (w/w) mannose after 30 and 12 minutes of reaction at 383 K and 413 K, respectively. This reactivity is also achieved when a 45 wt% glucose solution is converted. The Sn-Beta ctalyst can be used for multiple cycles, and the reaction stops when then solid is removed, clearly indicating that the catalysis is occurring heterogeneously. With isotopically labeled glucose, it is demonstrated (¹H and ¹³C MAS NMR spectroscopy) that the isomerization reaction catalyzed by Sn-Beta in water proceeds by way of an intramolecular hydride shift, confirming that framework tin center in Sn-Beta act as Lewis acids in aqueous media. Most importantly, the Sn-Beta catalyst is able to perform the isomerication reaction in highly acidic, aqueous environments with equivalent activity and product distribution as in media without added acid. This enables Sn-Beta to couple isomerizations with other acid-catalyzed reactions, including hydrolysis/isomerization or isomerization/dehydration reaction sequences, including starch to fructose and glucose to 5-hydrozymethylfurfural (HMF).

Biography

Mark E. Davis is the Warren and Katharine Schlinger Professor of Chemical Engineering at the California Institute of Technology and a member of the Experimental Therapeutics Program of the Comprehensive Cancer Center at the City of Hope in Duarte, California. His research in materials synthesis has resulted in more than 375 scientific publications, two textbooks, and more than 50 patents.

Dr. Davis is a founding editor of CaTTech and has been an associate editor of Chemistry of Materials and the AIChE Journal. He is the recipient of numerous awards, including the Colburn and Professional Progress Awards from the American Institute of Chemical Engineers (AIChE) and the Ipatieff, Langmuir, Murphree, and Gaden Prizes from the American Chemical Society (ACS).

The first engineer to win the National Science Foundation (NSF) Alan T. Waterman Award, Dr. Davis was elected to the National Academy of Engineering in 1997 and the National Academy of Sciences in 2006. The majority of Dr. Davis's research involves materials synthesis in two general areas: namely, zeolites and other solids that can be used for molecular recognition and catalysis, and polymers for the delivery of a broad range of therapeutics.