Oxydehydrogenation of isobutyric acid with heteropolyacid catalysts: Experimental observations of deactivation

the heteropolyacid catalysts H 5Mo 10V 2PO 40 and H 6Mo 9V 3PO 40 have been used for producing methacrylic acid via the oxydehydrogenation of isobutyric acid. This reaction proceeds via a redox process involving lattice oxygen from the Keggin structure of the catalyst molecules. Changes in the oxida...

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Bibliographic Details
Published inJournal of catalysis Vol. 124; no. 1; pp. 247 - 258
Main Authors Watzenberger, Otto, Emig, Gerhard, Lynch, David T.
Format Journal Article
LanguageEnglish
Published Amsterdam Elsevier Inc 01.07.1990
Elsevier
Subjects
Chemistry
Exact sciences and technology
General and physical chemistry
Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry
Heteropolyacid
Catalytic reaction
Deactivation
Stability
Carboxylic acid
Aliphatic compound
Dehydrogenation
Saturated compound
Oxidation
Experimental study
Catalyst activity
Catalyst
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Summary:the heteropolyacid catalysts H 5Mo 10V 2PO 40 and H 6Mo 9V 3PO 40 have been used for producing methacrylic acid via the oxydehydrogenation of isobutyric acid. This reaction proceeds via a redox process involving lattice oxygen from the Keggin structure of the catalyst molecules. Changes in the oxidation state of the catalyst produce a deactivation effect which is reversible by fully reoxidizing the catalyst. An irreversible, long-term type of deactivation related to a loss of molybdenum from the catalyst has also been observed. This occurs through the formation of a volatile Mocontaining gas-phase species. Passage of the IBA feed over a bed of molybdenum trioxide prior to entering the reactor eliminates both types of deactivation.
ISSN:0021-9517
1090-2694
DOI:10.1016/0021-9517(90)90120-9