Reduction and reoxidation of iron phosphate and its catalytic activity for oxidative dehydrogenation of isobutyric acid

Journal Article · Thu Feb 01 04:00:00 EST 1996 · Journal of Catalysis

DOI:https://doi.org/10.1006/jcat.1996.0039· OSTI ID:263693

Muneyama, E; Kunishige, A ^[1]; Ohda, K ^[2]

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1. UBE Scientific Analysis Lab., Kogushi (Japan)
2. UBE Industries, Ltd., Kogushi (Japan); and others

The freshly calcined iron phosphate catalysts with a P/Fe atomic ratio of 1.0 {approximately} 1.3 consist of amorphous phase, quartz-type FePO{sub 4} and/or tridymite-type FePO{sub 4} depending on the calcination temperature, though they contain only Fe{sup 3+} ions. In the absence of oxygen, the P/Fe > 1.2 catalyst samples are reduced with hydrogen or isobutyric acid to form Fe{sub 2}P{sub 2}O{sub 7} not passing through Fe{sub 3}(P{sub 2}O{sub 7}) nor FePO{sub 4}. While the P/Fe = 1.0 samples are reduced to Fe{sub 2}P{sub 2}O{sub 7} not passing through Fe{sub 3}(P{sub 2}O{sub 7}){sub 2}. During the use in the oxidative dehydrogenation of isobutyric acid, the freshly calcined catalysts are reduced to Fe{sub 3}(P{sub 2}O{sub 7}){sub 2}, the Fe{sub 2}P{sub 2}O{sub 7} catalysts are in part oxidized to the Y phase, and the Y phase is in part reduced to Fe{sub 2}P{sub 2}O{sub 7}, though the rates are very slow. The catalytic activity and selectivity are scarcely affected with the variation in the structure of the iron phosphate catalyst and in the oxidation states of iron ions. 15 Refs., 8 figs., 1 tab.

• OSTI ID: 263693
• Journal Information: Journal of Catalysis, Journal Name: Journal of Catalysis Journal Issue: 2 Vol. 158; ISSN 0021-9517; ISSN JCTLA5
• Country of Publication: United States
• Language: English

Related Subjects

10 SYNTHETIC FUELS
40 CHEMISTRY
CALCINATION
CATALYSTS
CATALYTIC EFFECTS
DEHYDROGENATION
IONS
IRON PHOSPHATES
ISOBUTYRIC ACID
OXIDATION
REDUCTION