Investigating reaction mechanisms of base-catalyzed isomerization of aldoses into ketoses for developing efficient catalytic processes

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Isomerization of aldoses into ketoses presents an industrially important reaction. It gives rise to keto-saccharides which are in high demand in food industry, manufacture of pharmaceuticals, synthesis of chiral organic compounds, and potentially for production of biofuels. Current industrial manufactures of ketoses rely on enzymatic processes, whereas chemo-catalytic methods present a number of advantages over biotechnological production. For example, the chemo-catalysts are of lower cost and less demanding to purity of feed. Moreover, thermostability of chemical catalysts typically excels the thermostability of enzymes, which enables operations at higher temperatures with a positive effect on the reaction rates and space-time-yields. Utilization of solid catalysts is especially beneficial considering ease of the catalyst separation and recycling. The current project focuses on investigating the base catalysts for isomerization of aldoses into ketoses with the ultimate goal to elaborate efficient tailor-made chemo-catalysts for these processes. Even though the isomerization over basic catalysts has been known for a long time, a molecular mechanism of this reaction is still poorly understood. At the same time, insight into the kinetics and mechanism of the isomerization (and of side reactions) should facilitate a knowledge-driven development of efficient catalysts.In this project the isomerization of glucose into fructose will be investigated in order to comprehend the kinetics and mechanism of the reaction depending on the nature of soluble and solid catalysts. The isomerization of other aldoses with various structures will be studied; and the dependence of the reaction efficiency on the structure of aldose will be obtained. Finally, stability of solid basic catalysts under the reaction conditions will be addressed. The correlations revealed in the study will provide fundamental understanding for a design of catalysts and catalytic processes for isomerization of aldoses into ketoses.