Catalytic properties of iron phosphate-based catalysts containing Fe{sub 2}(PO{sub 3}OH)P{sub 2}O{sub 7} and {alpha}- or {beta}-Fe{sub 3}(P{sub 2}O{sub 7}){sub 2} in the oxidative dehydrogenation of isobutyric acid

Journal Article · Sat Jun 01 04:00:00 EDT 1996 · Journal of Catalysis

DOI:https://doi.org/10.1006/jcat.1996.0177· OSTI ID:471616

Bonnet, P; Millet, J M.M. ^[1]

---

1. Universite Claude-Bernard, Villeurbanne (France)

The formation of {beta}- and {alpha}-Fe{sub 3}(P{sub 2}O{sub 7}){sub 2} along with Fe{sub 2}(PO{sub 3}OH)P{sub 2}O{sub 7}, in iron phosphate-based catalysts for oxidative dehydrogenation of isobutyric acid, has been studied by Moessbauer spectroscopy and X-ray diffraction. It has been shown that the crystallization of {beta}-Fe{sub 3}(P{sub 2}O{sub 7}){sub 2} in the catalysts under the conditions of catalysis is related to the presence in the amorphous precursors of these catalysts of particular ferrous species, whereas the crystallization of {alpha}-Fe{sub 3}(P{sub 2}O{sub 7}){sub 2} occurred when the catalysts were tested under low oxygen partial pressure. From a catalytic point of view, the {beta}-Fe{sub 3}(P{sub 2}O{sub 7}){sub 2} phase appeared to be poorly active and selective and without effect on the catalytic properties of Fe{sub 2}(PO{sub 3}OH)P{sub 2}O{sub 7}. On the contrary, the high activity and selectivity of {alpha}-Fe{sub 3}(P{sub 2}O{sub 7}){sub 2} were confirmed. Comparison of the catalytic properties of catalysts containing the same amount of {beta}-Fe{sub 3}(P{sub 2}O{sub 7}){sub 2} along with a large proportion of {alpha}-Fe{sub 3}(P{sub 2}O{sub 7}){sub 2} or Fe{sub 2}(PO{sub 3}OH)P{sub 2}O{sub 7} clearly showed that the catalytic properties of these two last phases were very close. This last feature has been proposed to be correlated with the presence at the surface of both phases under the conditions of catalysis of the same species [(PO{sub 3}OH){sup 2{minus}} and (Fe{sub 3}O{sub 12}){sup 16{minus}} or (Fe{sub 2}O{sub 9}){sup 13{minus}} groups]. 19 refs., 7 figs., 6 tabs.

• OSTI ID: 471616
• Journal Information: Journal of Catalysis, Journal Name: Journal of Catalysis Journal Issue: 1 Vol. 161; ISSN 0021-9517; ISSN JCTLA5
• Country of Publication: United States
• Language: English

Related Subjects

10 SYNTHETIC FUELS
40 CHEMISTRY
CATALYTIC EFFECTS
DEHYDROGENATION
HETEROGENEOUS CATALYSIS
IRON PHOSPHATES
ISOBUTYRIC ACID
MOESSBAUER EFFECT
OXIDATION
X-RAY DIFFRACTION