Fischer-Tropsch Synthesis of Hydrocarbons

Pichler and Schulz [7] suggested a third mechanism, which is worth considering and seeking to verify. According to this suggestion, a carbonyl of a metal in question is formed first, which is followed by the formation of formyl (in later 

There are several other mechanisms to be found in the literature, but the three just mentioned seem to be the most realistic and best supported. 

In 1974, the oil supply crisis stimulated research throughout the world on the Fischer-Tropsch Synthesis (FTS) of fuels. Surprisingly, the first result of this was evidence concerning the mechanism with typical FTS and methanation catalysts — Fe, Co, Ni (Ru) — the initiation step is the dissociation of CO [8] and not the formation of hydroxycarbene. 

Let us consider an experiment, shown schematically in Fig. 5.1 [8c]. The surface of a metal is partially covered by disproportionation of 13CO  

FTS is a process which is plagued by the self-poisoning of the catalyst, essentially 

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The second reaction is called the Fischer-Tropsch synthesis of hydrocarbons. Depending on the conditions and catalysts, a wide range of hydrocarbons from very light materials up to heavy waxes can be produced. Catalysts for the Fischer-Tropsch reaction iaclude iron, cobalt, nickel, and mthenium. Reaction temperatures range from about 150 to 350°C reaction pressures range from 0.1 to tens of MPa (1 to several hundred atm) (77). The Fischer-Tropsch process was developed iadustriaHy under the designation of the Synthol process by the M. W. Kellogg Co. from 1940 to 1960 (83). 

Many chemicals are produced from synthesis gas. This is a consequence of the high reactivity associated with hydrogen and carhon monoxide gases, the two constituents of synthesis gas. The reactivity of this mixture was demonstrated during World War II, when it was used to produce alternative hydrocarbon fuels using Fischer Tropsch technology. The synthesis gas mixture was produced then hy gasifying coal. Fischer Tropsch synthesis of hydrocarbons is discussed in Chapter 4. 

Ruthenium is known to catalyze a number of reactions, including the Fischer-Tropsch synthesis of hydrocarbons (7) and the polymerization of ethylene (2). The higher metal dispersions and the shape selectivity that a zeolite provides has led to the study of ruthenium containing zeolites as catalytic materials (3). A number of factors affect the product distribution in Fischer-Tropsch chemistry when zeolites containing ruthenium are used as the catalyst, including the location of the metal (4) and the method of introducing ruthenium into the zeolite (3). 

The Fischer-Tropsch synthesis of hydrocarbons is used on a large scale for fuel production in South Africa [78, 79]. Synthesis gas generated from coal in Lurgi fixed-bed gasifiers enters the Synthol reactor (Fig 18), where it is reacted over an iron catalyst at 340°C. The reactor works on the principle of the circulating fluidized bed. The mean porosity in the riser is 85%, and the gas velocity varies between 3 and 12ms1 [2]. Reaction heat is removed by way of heat-exchanger tube bundles placed inside the riser. 

The production of gasoline from methanol is a parallel process to the Fischer-Tropsch synthesis of hydrocarbons from syngas (Section 4.7.2). A shape-selective zeolite (ZSM-5) was the catalyst of choice in the process put on stream in 1987 by Mobil in New Zealand however the plant was later closed. The zeolite was used at ca. 400°C in a fluid catalyst reactor, which allows prompt removal of the heat of reaction. 

Heterogeneous gas-liquid-solid, e.g., catalytic Fischer-Tropsch synthesis of hydrocarbons from CO and H2... 

Many solid catalyzed reactions take place with one of the reactants absorbing from the gas phase into the liquid and reacting with a liquid reactant on the surface or inside the pores of a solid catalyst (see Fig. 7-15). Examples include the Fischer-Tropsch synthesis of hydrocarbons from synthesis gas (CO and H2) in the presence of Fe or Co-... 

ROLE OF SUPPORTS FOR CORALT-BASED CATALYSTS USED IN FISCHER-TROPSCH SYNTHESIS OF HYDROCARBONS... 

The reaction was discovered in Germany prior to World War II during an investigation of the effect of olefins on the Fischer-Tropsch synthesis of hydrocarbons . It is also called the oxo-synthesis, particularly in patents and other commercial literature. 

Examples include the Fischer-Tropsch synthesis of hydrocarbons from synthesis gas (CO and Ha) in the presence of Fe or Co-... 

Fischer-Tropsch Synthesis of Hydrocarbons and Fatty Acids... 

In principle also the possibility should be considered that CO is dissociated, as in Fischer-Tropsch synthesis of hydrocarbons, and thereafter partially hydrogenated. A metal carbene would then produce, upon addition of H2O, a molecule of methanol. However, one would expect that with a metal like Rh, which can dissociate CO, the isotopically labelled atoms from C 0 would be scrambled with C 0 atoms in the methanol product but this has not been found.With metals which dissociate CO even more reluctantly, like Pd and Cu, this mechanism is even less likely than with Rh. This does not however exclude the possibility that higher alcohols can be formed by H2O addition to a carbene-like intermediate. 

The versatility of CO as a synthon also stems from its ability to undergo insertion reactions into a variety of metal-heteroatom bonds. The migratory insertion of CO into transition metal-hydride bonds, while thermodynamically unfavorable, generates metal-formyl complexes M-C(0)H (Equation (19)), a few examples of which have been isolated independently. This reaction is assumed to be a key step in both the homogeneous and heterogeneous catalytic hydrogenation (i.e., reduction) of CO, including the Fischer-Tropsch synthesis of hydrocarbons and... 

Jahangiri H, Bennett J, Mahjoubi P, Wilson K, Gu S A review of advanced catalyst development for Fischer-Tropsch synthesis of hydrocarbons from biomass derived syn-gas, Catal Sci Technol 4 8) 2210-2229, 2014. http //dx.doi.org/10.1039/c4cy00327f. 

The Fischer-Tropsch synthesis of hydrocarbons, when using common iron or cobalt industrial catalysts, usually exhibits poor selectivity, especially regarding the carbon chain length. 

Presently the major step in the GTL conversion is considered to be the Fischer-Tropsch synthesis of hydrocarbons from synthesis gas (CO-I-H ). The classical processes produce waxes (solid hydrocarbons) that are further upgraded into the components of liquid fuels (gasoline, diesel). Diesel production by this technology seems to be the best solution. The synthetic diesel fuel has better characteristics compared to the fuel grades produced from oil (standard EN-590) the cetane number is 75 (versus 55 for the oil-derived diesel) the content of polynuclear aromatic compounds is 0.1 (versus 6%) the sulfur content is 0 ppm (versus 50 ppm). Such synthetic fuels can be used as additives to the oil-based diesel. GTL-diesel is used in Germany, Austria, and Sweden and the blends of the synthetic fuel and conventional diesel are used in France, Italy, and other countries. 

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