CO + H/sub 2/ reaction over nitrogen-modified iron catalysts. Quarterly technical progress report, October 1, 1983-December 30, 1983. [Denitriding of iron nitrides in both hydrogen and helium]
The synthesis of epsilon-Fe/sub 2.7/N is confirmed by Moessbauer spectroscopy. Carburization of epsilon-iron nitride for 2.5 hours in 3H/sub 2//CO at 523 K starts the formation of a bulk structure similar to that seen during ..gamma..'-iron nitride carburization. Reaction of ..gamma..'-Fe/sub 4/N in 3CO/H/sub 2/ synthesis gas at 523 K shows a better bulk stability than reaction in 3H/sub 2//CO. Kinetic analysis of the product distribution at the higher CO ratio confirms greater activity and selectivity maintainance. The kinetics of denitriding in both He and H/sub 2/ was studied with a mass spectrometer. Extremely rapid nitrogen loss was observed from both ..gamma..'-Fe/sub 4/N and epsilon-Fe/sub 2.7/N catalysts in H/sub 2/ at 523 K. In both cases a initial exposure to H/sub 2/ produced a significant amount of NH/sub 3/ which we ascribe to an active surface species. Hydrogenation of the bulk continued with a slow rise to a maximum about 90 seconds after the introduction of H/sub 2/. The denitriding activity of the epsilon-Fe/sub 2.7/N catalyst was significantly higher than that of the ..gamma..'-Fe/sub 4/N catalyst. In contrast, the denitriding rate of epsilon-Fe/sub 2.7/N in He was significantly slower than that in H/sub 2/ until high temperatures (773K) were reached. An overall activation energy of 41.5 kcal/mol was obtained for this process. Comparison of the denitriding rate of virgin epsilon-Fe/sub 2.7/N in H/sub 2/ with that of the same nitride after five minutes of carburization during the hydrocarbon synthesis reaction indicates large differences in the overall rate. The carburized nitride was some 300 times less active to bulk hydrogenation than the virgin catalyst, which is indicative of significant changes in the first few layers of the nitride during the initial minutes of the synthesis reaction. 17 references, 5 figures.
- Research Organization:
- Purdue Univ., West Lafayette, IN (United States)
- DOE Contract Number:
- FG22-82PC50804
- OSTI ID:
- 5317889
- Report Number(s):
- DOE/PC/50804-5; ON: DE84009046
- Resource Relation:
- Other Information: Portions are illegible in microfiche products. Original copy available until stock is exhausted
- Country of Publication:
- United States
- Language:
- English
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CO + H/sub 2/ reaction over nitrogen-modified iron catalysts. Quarterly technical progress report, January 1-March 31, 1984
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37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
01 COAL, LIGNITE, AND PEAT
CATALYSTS
SYNTHESIS
FISCHER-TROPSCH SYNTHESIS
IRON NITRIDES
CARBURIZATION
CATALYTIC EFFECTS
NITROGEN
DESORPTION
CHEMICAL REACTION KINETICS
EXPERIMENTAL DATA
HELIUM
HYDROGEN
MASS SPECTROSCOPY
MOESSBAUER EFFECT
RESEARCH PROGRAMS
CHEMICAL REACTIONS
DATA
ELEMENTS
FLUIDS
GASES
HARDENING
INFORMATION
IRON COMPOUNDS
KINETICS
NITRIDES
NITROGEN COMPOUNDS
NONMETALS
NUMERICAL DATA
PNICTIDES
RARE GASES
REACTION KINETICS
SPECTROSCOPY
SURFACE HARDENING
SURFACE TREATMENTS
TRANSITION ELEMENT COMPOUNDS
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400201 - Chemical & Physicochemical Properties
010405 - Coal
Lignite
& Peat- Hydrogenation & Liquefaction