Catalytic properties of Fe/sub 2/O/sub 3//Sb/sub 2/O/sub 4/ mixed oxides--1. Mechanism of propene oxidation
On a catalyst containing a 1:1 antimony-iron ratio (Sb/Fe) and consisting entirely of FeSbO/sub 4/, and on a catalyst containing a 2:1 antimony-iron ratio (2Sb/Fe) and consisting of FeSbO/sub 4/ and Sb/sub 2/O/sub 4/, the acrolein yields from propylene oxidation at 400/sup 0/C were similar, but Sb/Fe was also active in the deep oxidation of propylene to carbon dioxide, i.e., 2Sb/Fe had a much higher acrolein selectivity. The rate constants for acrolein formation, i.e., catalyst reduction, and for catalyst reoxidation were determined. Catalyst reduction with propylene showed initial rapid acrolein (and CO/sub 2/) formation until the surface oxygen was consumed, and then much slower formation of acrolein, 1,5-hexadiene, and CO/sub 2/, which was identical for both catalysts and corresponded to bulk reduction. The initial rapid acrolein formation was first order in propylene and second order in surface oxygen. Acrolein formation apparently proceeds via an allyl intermediate whose attack of surface oxygen (i.e., the second surface reaction step) is rate-controlling. The presence of Sb/sub 2/O/sub 4/ in 2Sb/Fe apparently modifies the catalyst surface structure to provide oxygen for the selectiive acrolein formation.
- Research Organization:
- Kyushu Univ.
- OSTI ID:
- 6456610
- Journal Information:
- J. Catal.; (United States), Vol. 64:1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ACROLEIN
CHEMICAL REACTION YIELD
ANTIMONY
CATALYTIC EFFECTS
IRON
PROPYLENE
OXIDATION
CATALYSTS
CHEMICAL ACTIVATION
CHEMICAL REACTION KINETICS
CONCENTRATION RATIO
OXYGEN
SURFACE PROPERTIES
ALDEHYDES
ALKENES
CHEMICAL REACTIONS
ELEMENTS
HYDROCARBONS
KINETICS
METALS
NONMETALS
ORGANIC COMPOUNDS
REACTION KINETICS
TRANSITION ELEMENTS
YIELDS
400301* - Organic Chemistry- Chemical & Physicochemical Properties- (-1987)
400201 - Chemical & Physicochemical Properties