Fe-P-O catalysts for methane utilization - Catalyst development and identification
- Univ. of Michigan, Ann Arbor (USA)
Fe-P-O catalyst formulations show great promise for oxidative coupling of methane. They attain yields of C{sub 2} hydrocarbons comparable to the best in the literature at a temperature which is far below those reported. The catalysts are active in both supported (on Cab-O-Sil) and unsupported (bulk) forms. Both these forms are active around Fe:P ratios of 0.6, suggesting that the pathway in general is unaltered by the support. The first gas-phase product of the reaction appears to be ethane, which is subsequently converted to ethylene. CO and CO{sub 2} seem to be formed by oxidation of the C{sub 2} hydrocarbons. Activity testing also revealed that a catalyst of this active composition was not always active, indicating a possible bifurcation in the reaction rate. The existence of rate hysteresis is confirmed by temperature-programming experiments. ESCA and FTIR studies indicate that the active catalysts are composed of a mixture of various hydrated and unhydrated iron phosphates. The authors speculate that a possible active site for the dehydrogenation is the P-O-P bridge structure of the polyphosphates. They find that on supported catalysts, dehydrogenating species actually build up on the surface during the reaction. These species are specific to dehydrogenation and appear to be incapable of effecting any further oxidation of the products. Thus, gas-phase oxygen alone is responsible for the formation of carbon monoxide and dioxide, while the dehydrogenating oxidic species on the surface are primarily responsible for the formation of C{sub 2} hydrocarbons. This suggests that forced concentration cycling would be a good way of separating products of the reaction on supported catalysts.
- OSTI ID:
- 6350827
- Journal Information:
- Journal of Catalysis; (USA), Vol. 123:1; ISSN 0021-9517
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
IRON OXIDES
CATALYTIC EFFECTS
METHANE
CATALYTIC REFORMING
OXIDATION
PHOSPHORUS OXIDES
CARBON DIOXIDE
CARBON MONOXIDE
CATALYSIS
CATALYST SUPPORTS
CHEMICAL BONDS
CHEMICAL REACTION KINETICS
CRYSTAL STRUCTURE
DEHYDROGENATION
ELECTRON SPECTROSCOPY
ETHANE
ETHYLENE
FOURIER TRANSFORMATION
INFRARED SPECTRA
PROCESS CONTROL
QUANTITY RATIO
SEPARATION PROCESSES
SURFACE PROPERTIES
SYNTHESIS
ALKANES
ALKENES
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
CONTROL
HYDROCARBONS
INTEGRAL TRANSFORMATIONS
IRON COMPOUNDS
KINETICS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHOSPHORUS COMPOUNDS
REACTION KINETICS
REFORMER PROCESSES
SPECTRA
SPECTROSCOPY
TRANSFORMATIONS
TRANSITION ELEMENT COMPOUNDS
030300* - Natural Gas- Drilling
Production
& Processing