(81g) Molecular Investigation of Catalytic Isomerization of Glucose to Fructose

Conversion of carbohydrates, the key components of biomass, to various intermediates, such as 5-hydroxymethyl-furfural (HMF), has gained significant attention in recent years. Even though some success has been achieved in the dehydration of fructose to HMF, there is a pressing need to selectively transform glucose, the most dominant sugar in biomass, to HMF. The pathway to HMF from glucose is believed to involve isomerization of glucose to fructose. In order to convert glucose to HMF, via fructose, in a single reactor system, it is desired to have a catalyst which actively converts glucose to fructose in an aqueous environment. Recent experimental studies at the Catalysis Center for Energy Innovation have demonstrated promising results using various catalysts, such as tin, chromium, titanium. Among them, the tin-beta zeolite catalyst can give considerably good performance. In the present work, we successfully adopt a first principles molecular modeling approach to investigate the fundamentals of the catalytic isomerization reaction, in explicit aqueous medium. Stepwise mechanistic details of the reaction and the dynamics and energetics of individual steps are computed. Results are compared to new experimental data obtained via combining a range of analytical, NMR, and other spectroscopic methods. Molecular details obtained from the present work serve as an input for developing and designing novel catalytic materials for the glucose isomerization reaction, thus providing for the first time a bottom-up approach of catalyst design for biomass conversion reactions.