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11 results on '"Tempelman, Christiaan H.L."'

8. Deactivation of Sn-Beta during carbohydrate conversion

Author

Van Der Graaff, William N.p., Tempelman, Christiaan H.l., Hendriks, Frank C., Ruiz-martinez, Javier, Bals, Sara, Weckhuysen, Bert M., Pidko, Evgeny A., Hensen, Emiel J.m., Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis, Inorganic Materials & Catalysis, Chemical Engineering and Chemistry, Sub Inorganic Chemistry and Catalysis, and Inorganic Chemistry and Catalysis

Subjects
Catalyst deactivation, 010402 general chemistry, Photochemistry, 01 natural sciences, Catalysis, chemistry.chemical_compound, Fluorescence microscope, Zeolite, Biology, Flow chemistry, Ethanol, Biomass conversion, 010405 organic chemistry, Process Chemistry and Technology, organic chemicals, Carbohydrate, 0104 chemical sciences, Solvent, Chemistry, Confocal fluorescence microscopy, chemistry, Zeolite catalysis, Isomerization, Sn-Beta
Abstract

The deactivation of Sn-Beta zeolite catalyst during retro-aldolization and isomerization of glucose is investigated. Confocal fluorescence microscopy reveals that retro-aldolization of glucose in CH3OH at 160 °C is accompanied with the build-up of insoluble oligomeric deposits in the micropores, resulting in a rapid catalyst deactivation. These deposits accumulate predominantly in the outer regions of the zeolite crystals, which points to mass transport limitations. Glucose isomerization in water is not only accompanied by the formation of insoluble deposits in the micropores, but also by the structural degradation of the zeolite due to desilication and destannation. Enhanced and sustained catalytic performance can be achieved by using ethanol/water mixtures as the reaction solvent instead of water.

Published
2018

9. Deactivation of Sn-Beta during carbohydrate conversion

Author

Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis, Van Der Graaff, William N.p., Tempelman, Christiaan H.l., Hendriks, Frank C., Ruiz-martinez, Javier, Bals, Sara, Weckhuysen, Bert M., Pidko, Evgeny A., Hensen, Emiel J.m., Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis, Van Der Graaff, William N.p., Tempelman, Christiaan H.l., Hendriks, Frank C., Ruiz-martinez, Javier, Bals, Sara, Weckhuysen, Bert M., Pidko, Evgeny A., and Hensen, Emiel J.m.

Published
2018

10. Competitive Adsorption of Substrate and Solvent in Sn-Beta Zeolite During Sugar Isomerization

Author

van der Graaff, William N.P., Tempelman, Christiaan H.L., Li, Guanna, Mezari, Brahim, Kosinov, Nikolay, Pidko, Evgeny A., Hensen, Emiel J.M., van der Graaff, William N.P., Tempelman, Christiaan H.L., Li, Guanna, Mezari, Brahim, Kosinov, Nikolay, Pidko, Evgeny A., and Hensen, Emiel J.M.

Abstract

The isomerization of 1,3-dihydroxyactone and d-glucose over Sn-Beta zeolite was investigated by in situ 13C 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.

Published
2016

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