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Effect of Cesium and Phosphate Addition to Mo/V/W Mixed Oxide Catalysts for the Gas Phase Oxidation of Methacrolein to Methacrylic Acid

Sennerich, Maximilian 1; Weidler, Peter G. 2; Heißler, Stefan 2; Kraushaar-Czarnetzki, Bettina 1
1 Institut für Chemische Verfahrenstechnik (CVT), Karlsruher Institut für Technologie (KIT)
2 Institut für Funktionelle Grenzflächen (IFG), Karlsruher Institut für Technologie (KIT)

Abstract:
The present study investigates modified Mo/V/W mixed oxides as a possible alternative for state of the art heteropoly acid catalysts (HPA) in the partial oxidation of methacrolein (MAC) to methacrylic acid (MAA). Even though HPAs show an excellent activity and MAA selectivity, their long-term stability is unsatisfying, rendering the catalyst inoperable after runtimes of roughly 6 months. Mo/V/W mixed oxides consisting of M1 and a hexagonal (Mo,V,W)O$_{x}$-phase (h-phase) in varying proportions were modified by impregnation with aqueous solutions containing cesium and phosphate ions. All samples were characterized with respect to specific surface area, crystallinity, elemental and phase composition. The catalytic performance in the oxidation of MAC to MAA was investigated using a continuously operated reaction unit with tubular fixed bed reactor. Impregnation with cesium and phosphate ions and subsequent heating triggers the transformation of the mixed oxide into a Keggin-type HPA, whereby the h-phase is more reactive than M1. The transformation into HPA is accompanied by a change in the catalytic properties, i.e., the selectivity to MAA is considerably improved. ... mehr


Verlagsausgabe §
DOI: 10.5445/IR/1000134553
Veröffentlicht am 30.06.2021
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Chemische Verfahrenstechnik (CVT)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2021
Sprache Englisch
Identifikator ISSN: 2073-4344
KITopen-ID: 1000134553
Erschienen in Catalysts
Verlag MDPI
Band 11
Heft 2
Seiten 231
Bemerkung zur Veröffentlichung Gefördert durch den KIT-Publikationsfonds
Vorab online veröffentlicht am 09.02.2021
Nachgewiesen in Web of Science
Scopus
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