A Continuous Flow Strategy for the Coupled Transfer Hydrogenation and Etherification of 5-(Hydroxymethyl)furfural using Lewis Acid Zeolites

• Published in: ChemSusChem 2014-08, Vol.7 (8), p.2255-2265
• Main Authors: Lewis, Jennifer D., Van de Vyver, Stijn, Crisci, Anthony J., Gunther, William R., Michaelis, Vladimir K., Griffin, Robert G., Román-Leshkov, Yuriy
• Format: Article
• Language: English
• Subjects: biomass conversion; Butanols - chemistry; cascade reactions; Catalysis; Ethers - chemistry; Furaldehyde - analogs & derivatives; Furaldehyde - chemistry; hydrogen transfer; Hydrogenation; Lewis Acids - chemistry; solid lewis acids; Water - chemistry; Zeolites; Zeolites - chemistry
• ISSN: 1864-5631; 1864-564X
• DOI: 10.1002/cssc.201402100

Hf‐, Zr‐ and Sn‐Beta zeolites effectively catalyze the coupled transfer hydrogenation and etherification of 5‐(hydroxymethyl)furfural with primary and secondary alcohols into 2,5‐bis(alkoxymethyl)furans, thus making it possible to generate renewable fuel additives without the use of external hydrogen sources or precious metals. Continuous flow experiments reveal nonuniform changes in the relative deactivation rates of the transfer hydrogenation and etherification reactions, which impact the observed product distribution over time. We found that the catalysts undergo a drastic deactivation for the etherification step while maintaining catalytic activity for the transfer hydrogenation step. 119Sn and 29Si magic angle spinning (MAS) NMR studies show that this deactivation can be attributed to changes in the local environment of the metal sites. Additional insights were gained by studying effects of various alcohols and water concentration on the catalytic reactivity. Go with the continuous flow: The title reaction was investigated under continuous flow conditions in the presence of Hf‐, Zr‐, and Sn‐Beta zeolites. Product distribution studies and a thorough characterization of the catalysts reveal that their deactivation can be correlated to changes in the local environment of the metal sites.