A critical review of the kinetics and selectivity of the Fischer–Tropsch synthesis (FTS) is given. The focus is on reaction mechanisms and kinetics of the water–gas shift and Fischer–Tropsch (FT) reactions. New developments in the product selectivity as well as the overall kinetics are reviewed. It is concluded that the development of rate equations for the FTS should be based on realistic mechanistic schemes. Qualitatively, there is agreement that the product distribution is affected by the occurrence of secondary reactions (hydrogenation, isomerization, reinsertion, and hydrogenolysis). At high CO and H2O pressures, the most important secondary reaction is readsorption of olefins, resulting in initiation of chain growth processes. Secondary hydrogenation of α-olefins may occur and depends on the catalytic system and the process conditions. The rates of the secondary reactions increase exponentially with chain length. Much controversy exists about whether these chain-length dependencies stem from differe...

Kinetics and Selectivity of the Fischer–Tropsch Synthesis: A Literature Review

CATALYTIC CONVERSION OF METHANE TO MORE USEFUL CHEMICALS AND FUELS: A CHALLENGE FOR THE 21st CENTURY

Hydrogen production reactions from carbon feedstocks: fossil fuels and biomass.

The efficient use of natural gas will require catalysts that can activate the first C-H bond of methane while suppressing complete dehydrogenation and avoiding overoxidation. We report that single iron sites embedded in a silica matrix enable direct, nonoxidative conversion of methane, exclusively to ethylene and aromatics. The reaction is initiated by catalytic generation of methyl radicals, followed by a series of gas-phase reactions. The absence of adjacent iron sites prevents catalytic C-C coupling, further oligomerization, and hence, coke deposition. At 1363 kelvin, methane conversion reached a maximum at 48.1% and ethylene selectivity peaked at 48.4%, whereas the total hydrocarbon selectivity exceeded 99%, representing an atom-economical transformation process of methane. The lattice-confined single iron sites delivered stable performance, with no deactivation observed during a 60-hour test.

Direct, Nonoxidative Conversion of Methane to Ethylene, Aromatics, and Hydrogen

https://dspace.library.uu.nl/bitstream/handle/1874/26040/Catal.Today-Weckhuysen-2003.pdf?sequence=1

Chemistry, spectroscopy and the role of supported vanadium oxides in heterogeneous catalysis

Characterization of a Mo/ZSM-5 catalyst for the conversion of methane to benzene

Conversion of methane to benzene over transition metal ion ZSM-5 zeolites : I. Catalytic characterization

Activation studies with a precipitated iron catalyst for Fischer-Tropsch synthesis. I. Characterization studies

Dehydroaromatization of methane to benzene occurs over a 2 wt% Mo/ZSM-5 catalyst at 700‡C under non-oxidizing conditions. Following an initial induction period, during which CH4 reactant reduces the original Mo6+ ions in the zeolite to Mo2C and deposition of coke occurs, a benzene selectivity of ∼ 70% at a CH4 conversion of 8–10% could be sustained for more than 16 h. X-ray photoelectron spectroscopy and X-ray powder diffraction measurements indicate that the reduced Mo is highly dispersed in the channels of the zeolite. Initial activation of CH4 reactant occurs on Mo2C sites, leading to the formation of C2H4 as the primary product. The latter then undergoes subsequent oligomerization reactions on acidic sites of the zeolite to form aromatic products.

Dingjun Wang

Papers

Characterization of a Mo/ZSM-5 catalyst for the conversion of methane to benzene

Conversion of methane to benzene over transition metal ion ZSM-5 zeolites : I. Catalytic characterization

Activation studies with a precipitated iron catalyst for Fischer-Tropsch synthesis. I. Characterization studies

Catalytic conversion of methane to benzene over Mo/ZSM-5

Oxidative Coupling of Methane over Oxide-Supported Sodium-Manganese Catalysts