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Mechanistic Insights into the Selective Oxidation of 5-(Hydroxymethyl)furfural over Silver-based Catalysts

Schade, Oliver Robert; Gaur, Abhijeet; Zimina, Anna; Saraci, Erisa; Grunwaldt, Jan-Dierk

Abstract:
Silver-catalyzed oxidation of 5-(hydroxymethyl)furfural (HMF) to 5-hydroxymethyl-2-furancarboxylic acid (HFCA) was investigated using Ag/ZrO$_{2}$ and Ag/TiO$_{2}$ catalysts. The reaction proceeded very selectively without formation of the dicarboxylic acid in the presence of air and NaOH as a base. In situ X-ray absorption spectroscopy (XAS) performed systematically under varying reaction conditions in a specially designed cell evidenced that reduced silver particles are the catalytically active species in this reaction. Although an incomplete reduction of Ag/ZrO$_{2}$ and Ag/TiO$_{2}$ was observed after the catalyst preparation even after reduction in hydrogen, silver was reduced to the metallic state as soon as HMF was introduced to the reaction mixture at room temperature and stayed reduced throughout the reaction under conditions optimized for high HFCA yield. The degree of silver reduction and product formation differed for varying reaction conditions, indicating that reduced silver particles, a homogeneous base and oxygen are needed in order to achieve high HFCA yield. Based on the catalytic and spectroscopic experiments, a detailed reaction mechanism is proposed involving a dehydrogenation pathway of an intermediately formed geminal diol in basic aqueous solution.

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Verlagsausgabe §
DOI: 10.5445/IR/1000120838
Veröffentlicht am 10.10.2020
Originalveröffentlichung
DOI: 10.1039/D0CY00878H
Scopus
Zitationen: 2
Dimensions
Zitationen: 2
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Katalyseforschung und -technologie (IKFT)
Institut für Technische Chemie und Polymerchemie (ITCP)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2020
Sprache Englisch
Identifikator ISSN: 2044-4753, 2044-4761
KITopen-ID: 1000120838
HGF-Programm 37.03.01 (POF III, LK 01) Catalysts and Mechanisms
Weitere HGF-Programme 56.98.01 (POF III, LK 01) Betrieb in MML
Erschienen in Catalysis science & technology
Verlag Royal Society of Chemistry (RSC)
Band 10
Heft 15
Seiten 5036-5047
Vorab online veröffentlicht am 02.07.2020
Nachgewiesen in Web of Science
Dimensions
Scopus
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