Solvent effects in acid-catalyzed biomass conversion reactions.

Authors :: Mellmer MA
Sener C
Gallo JM
Luterbacher JS
Alonso DM
Dumesic JA
Source :: Angewandte Chemie (International ed. in English) [Angew Chem Int Ed Engl] 2014 Oct 27; Vol. 53 (44), pp. 11872-5. Date of Electronic Publication: 2014 Sep 11.
Publication Year :: 2014
Abstract: Reaction kinetics were studied to quantify the effects of polar aprotic organic solvents on the acid-catalyzed conversion of xylose into furfural. A solvent of particular importance is γ-valerolactone (GVL), which leads to significant increases in reaction rates compared to water in addition to increased product selectivity. GVL has similar effects on the kinetics for the dehydration of 1,2-propanediol to propanal and for the hydrolysis of cellobiose to glucose. Based on results obtained for homogeneous Brønsted acid catalysts that span a range of pKa values, we suggest that an aprotic organic solvent affects the reaction kinetics by changing the stabilization of the acidic proton relative to the protonated transition state. This same behavior is displayed by strong solid Brønsted acid catalysts, such as H-mordenite and H-beta.<br /> (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)