Tin-containing zeolite for the isomerization of cellulosic sugars

Isomerization reactions starting with dihydroxyacetone (DHA), xylose, and glucose in water were catalyzed by Sn-MFI and Sn-BEA zeolites. Sn-BEA was more active than Sn-MFI for glucose, while both catalysts were able to isomerize dihydroxyacetone and xylose. After 210 min at 90 °C, the yields of lactic acid, xylulose, and fructose using Sn-BEA were 54%, 24%, and 34%, respectively, at conversions of 93%, 81%, and 65%, respectively. Using Sn-MFI, the yields were 65%, 19%, and 4%, respectively, at conversions of 98%, 40%, and 9%, respectively. Pore size limitations, substrate sizes, and catalyst surface area all contribute to the strong activity of Sn-BEA for all three sugars; however, Sn-MFI is easier to make and may be suitable for reactions involving smaller molecules.

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► Sn-BEA is active for isomerization of dihydroxyacetone, xylose, and glucose in water.
► Sn-MFI is active for isomerization of dihydroxyacetone and xylose in water.
► Sn-MFI has better selectivity than Sn-BEA for certain products.