Mineral acid-catalyzed conversion of naturally abundant glucose (aldose) to platform chemicals such as hydroxy-methyl-furfural (HMF) and levulinic in aqueous solutions suffer a major drawback of poor selectivity, while fructose (ketose) yields HMF or levulinic acid with high selectivity. Recently, it has been reported that large pore Tin-beta zeolite can catalyze the isomerization of aldose to ketose analogous to enzyme Xylose isomerase. In this paper, we report detailed reaction mechanism of isomerization of glyceraldehyde, glucose to dihydroxyacetone and fructose, respectively by Tin/Ti-beta zeolite active site models using the DFT and MP2 levels of theory. Both hydroxylated sites (open site) and non-hydroxylated (close) sites were chosen for this investigation of Ti-beta. Additionally, the influence of the number of hydroxyl groups and alkali metal ions (Na+) on the glucose isomerization process will be discussed. The concept behind this paper is to identify the active site of Tin/Ti-beta zeolites and suggest a reaction pathway through the simulated results.  This work was supported by the U.S. Department of Energy under Contract DE-AC0206CH11357.  This material is based upon work supported as part of the Institute for Atom-efficient Chemical Transformations (IACT), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, and Office of Basic Energy Sciences.

Aldose to ketose conversion using Tin/Ti-Lewis acid models: A computational study

243rd National Meeting (2012)

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