Competitive Adsorption of Substrate and Solvent in Sn‐Beta Zeolite During Sugar Isomerization. Issue 22 (28th October 2016)

• Record Type: Journal Article
• Authors: van der Graaff, William N. P.; Tempelman, Christiaan H. L.; Li, Guanna; Mezari, Brahim; Kosinov, Nikolay; Pidko, Evgeny A.; Hensen, Emiel J. M.
• Is Part Of: ChemSusChem. Volume 9:Issue 22(2016:Nov.)
• Page Start: 3145
• Page End: 3149
• Publication Date: 2016-10-28
• Subjects: carbohydrates -- competitive adsorption -- Lewis acids -- Sn-beta -- solvent replacement; Green chemistry -- Periodicals; Sustainable engineering -- Periodicals; Chemistry -- Periodicals; Chemical engineering -- Periodicals; 660
• DOI: 10.1002/cssc.201600800
• Languages: English
• ISSNs: 1864-5631

Abstract

Abstract: The isomerization of 1, 3‐dihydroxyactone andd ‐glucose over Sn‐Beta zeolite was investigated by in situ 13 C NMR spectroscopy. The conversion rate at room temperature is higher when the zeolite is dehydrated before exposure to the aqueous sugar solution. Mass transfer limitations in the zeolite micropores were excluded by comparing Sn‐Beta samples with different crystal sizes. Periodic density functional theory (DFT) calculations show that sugar and water molecules compete for adsorption on the active framework Sn centers. Careful solvent selection may thus increase the rate of sugar isomerization. Consistent with this prediction, batch catalytic experiments show that the use of a co‐solvent, such as tetrahydrofuran, that strongly interacts with the Sn centers suppresses glucose isomerization. On the other hand, the use of ethanol as cosolvent results in significantly higher isomerization activity in comparison with pure water because of decreased competition with glucose adsorption on zeolitic Sn sites. Abstract : Ring the bell : Competition between sugar and solvent molecules on the active sites of Sn‐Beta zeolite affect the activity of Sn‐Beta in carbohydrate isomerization. By changing the solvent from THF to water to ethanol, higher rates are obtained because of decreased competition with glucose.