Silica-supported iron nitride in Fischer-Tropsch reactions. II. Comparison of the promotion effects of potassium and nitrogen on activity and selectivity

Journal Article · Fri Feb 01 04:00:00 EST 1985 · J. Catal.; (United States)

DOI:https://doi.org/10.1016/0021-9517(85)90338-0· OSTI ID:5466037

Yeh, E B; Schwartz, L H; Butt, J B

The performance of silica-supported iron catalysts promoted by potassium and nitrogen has been studied for the conversion of CO to hydrocarbons. Reactions were investigated at 250/sup 0/C and 1, 7.8, and 14 atm in a differential conversion range of less than 6%. Significant differences exist in the behavior of these supported catalysts in comparison to prior studies of fused or precipitated materials. It was found that an unpromoted Fe-carbide catalyst was more active at lower pressures and less active at higher pressures than the nitrided catalyst. Moreover, it was found that potassium-promoted catalysts were less active than catalysts without potassium. Both Fe-nitride and potassium-promoted catalysts showed higher olefin selectivities, higher water-gas shift activity, lower alcohol yields, and larger proportions of higher molecular weight products than their unpromoted counterparts. The product distributed parameters are presented for all catalysts at different pressures and conversion levels. The significance of the incorporation of alcohols into the distribution plot is discussed and a mechanism for alcohol formation is proposed. The effect of nitrogen on the catalytic reaction is discussed in terms of a donor model theory in which nitrogen atoms donate electrons to the iron d band. From the product distribution of the supported Fe-nitride and potassium-promoted catalysts, it is concluded that nitrogen and potassium have similar promoting function on the Fischer-Tropsch reactions and further that an additive effect is observed for Fe-K-nitride catalysts. 31 refs.

• Research Organization: Northwestern Univ., Evanston, IL
• OSTI ID: 5466037
• Journal Information: J. Catal.; (United States), Journal Name: J. Catal.; (United States) Vol. 91:2; ISSN JCTLA
• Country of Publication: United States
• Language: English

Related Subjects

090121* -- Hydrocarbon Fuels-- Chemical Synthesis-- (1976-1989)
10 SYNTHETIC FUELS
ACTIVATION ENERGY
ADSORBENTS
ALCOHOLS
ALKALI METALS
ALKENES
CARBIDES
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATALYSTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTIONS
CHEMISORPTION
COHERENT SCATTERING
DATA
DIFFRACTION
ELEMENTS
ENERGY
ETHANOL
ETHYLENE
EXPERIMENTAL DATA
FISCHER-TROPSCH SYNTHESIS
GAMMA SPECTROMETERS
HIGH TEMPERATURE
HYDROCARBONS
HYDROXY COMPOUNDS
INFORMATION
IRON CARBIDES
IRON COMPOUNDS
IRON NITRIDES
MANAGEMENT
MEASURING INSTRUMENTS
MEDIUM PRESSURE
METALS
METHANOL
MINERALS
MOESSBAUER SPECTROMETERS
NITRIDES
NITROGEN
NITROGEN COMPOUNDS
NONMETALS
NUMERICAL DATA
ORGANIC COMPOUNDS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PNICTIDES
POTASSIUM
PROCESSING
PROMOTERS
SCATTERING
SEPARATION PROCESSES
SILICA
SILICA GEL
SILICON COMPOUNDS
SILICON OXIDES
SORPTION
SPECTROMETERS
SYNGAS PROCESS
TRANSITION ELEMENT COMPOUNDS
WASTE MANAGEMENT
WASTE PROCESSING
X-RAY DIFFRACTION