Fe-P-O catalysts for methane utilization - Catalyst development and identification

Journal Article · Tue May 01 04:00:00 EDT 1990 · Journal of Catalysis; (USA)

DOI:https://doi.org/10.1016/0021-9517(90)90162-D· OSTI ID:6350827

Annapragada, A V; Gulari, E ^[1]

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1. 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), Journal Name: Journal of Catalysis; (USA) Vol. 123:1; ISSN 0021-9517; ISSN JCTLA
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
030300* -- Natural Gas-- Drilling
Production
& Processing
ALKANES
ALKENES
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON MONOXIDE
CARBON OXIDES
CATALYSIS
CATALYST SUPPORTS
CATALYTIC EFFECTS
CATALYTIC REFORMING
CHALCOGENIDES
CHEMICAL BONDS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CONTROL
CRYSTAL STRUCTURE
DEHYDROGENATION
ELECTRON SPECTROSCOPY
ETHANE
ETHYLENE
FOURIER TRANSFORMATION
HYDROCARBONS
INFRARED SPECTRA
INTEGRAL TRANSFORMATIONS
IRON COMPOUNDS
IRON OXIDES
KINETICS
METHANE
ORGANIC COMPOUNDS
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PHOSPHORUS COMPOUNDS
PHOSPHORUS OXIDES
PROCESS CONTROL
QUANTITY RATIO
REACTION KINETICS
REFORMER PROCESSES
SEPARATION PROCESSES
SPECTRA
SPECTROSCOPY
SURFACE PROPERTIES
SYNTHESIS
TRANSFORMATIONS
TRANSITION ELEMENT COMPOUNDS