Oxidative dehydrogenation of butenes over zinc ferrite catalysts

Thesis/Dissertation · Thu Jan 01 04:00:00 EST 1987

OSTI ID:6885012

Park, T J

The oxidative dehydrogenation (OXD) of butene over a zinc ferrite catalyst was studied in a batch recirculation and microcatalytic pulse reactor system at temperatures between 300 and 400/sup 0/C. Mechanistic features of the reaction were examined using deuterium-labeled butene and /sup 18/O-labeled carbon dioxide experiments. Solid-state changes in the catalyst were examined through x-ray powder diffraction and Moessbauer spectroscopy. Reaction products consist of 1,3-butadiene, carbon dioxide, water, and butene isomers. Kinetic expressions were constructed for both OXD and deep oxidation reactions based on a two site Langmuir-Hinshelwood model assuming dissociative adsorption for oxygen on one site and competitive adsorption by butene and butadiene on the other. The OXD of perdeuterated butene is slower than that of undeuterated butene, which indicates a significant kinetic isotope effect of 2.7 at 350/sup 0/C. A similar effect was observed for isomerization of cis-2-butene to 1-butene by double bond shift (1.4 at 350/sup 0/C). Apparently, carbon-hydrogen bond cleavage is involved in the rate limiting step for both reactions. Microcatalytic pulse experiments carried out in the absence of gas phase oxygen indicated that the lattice oxygen does not participate in the reaction and that the migration of bulk oxygen to the surface of the catalyst is very slow under these conditions. A similar results was observed in /sup 18/O exchange experiments with C/sup 18/O/sub 2/. The experimental data are consistent with an oxidation-reduction cycle involving Fe/sup +2//Fe/sup +3/ interconversion. Increased catalytic activity at higher temperatures is believed to be due to an enhancement of catalytic activity by iron oxides formed by the decomposition of zinc ferrite into zinc oxide and iron oxide.

• Research Organization: Kansas Univ., Kansas City (USA). Medical Center
• OSTI ID: 6885012
• Country of Publication: United States
• Language: English

Related Subjects

090110* -- Hydrocarbon Fuels-- Properties-- (1979-1989)
10 SYNTHETIC FUELS
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400202 -- Isotope Effects
Isotope Exchange
& Isotope Separation
ALKENES
BUTENES
CATALYSIS
CATALYTIC EFFECTS
CHEMICAL REACTIONS
DEHYDROGENATION
EVEN-EVEN NUCLEI
FERRIMAGNETIC MATERIALS
FERRITES
HYDROCARBONS
IRON COMPOUNDS
ISOTOPE APPLICATIONS
ISOTOPES
LABELLED COMPOUNDS
LIGHT NUCLEI
MAGNETIC MATERIALS
MATERIALS
NUCLEI
ORGANIC COMPOUNDS
OXIDATION
OXYGEN 18
OXYGEN COMPOUNDS
OXYGEN ISOTOPES
STABLE ISOTOPES
TEMPERATURE EFFECTS
TRACER TECHNIQUES
TRANSITION ELEMENT COMPOUNDS
ZINC COMPOUNDS