Catalysis Fischer-Tropsch process

Thermochemical biomass-to-liquid (BtL) conversion, involving thermal gasification of the biomass and subsequent synthesis of biofuels by the Fischer-Tropsch process. Various aspects of the use of catalysis in this process are discussed in the several chapters. 

Free organic ketenes are very reactive molecules. They can be stabilized by transition metal complexes. Transition metal ketene complexes are important intermediates in catalysis, such as in the Fischer-Tropsch process . Ketenes can be bonded to transition metal conq>lexes in a wide variety of ways . The two common bonding modes for mononuclear ketene complexes are r -(C, O) and ti -(C, C). The ii -(C, O) mode is considered to be favored by early transition metal complexes due to the electrophiUc properties of the metals, while the r] -(C, C) mode is preferred by late transition metals. Indeed, several nickel ketene conq)lexes have been characterized spectroscopically to have the C) bonding mode, and these ketene complexes have demonstrated nmch... 

Catalysis by Metal Ousters in Zeolites. There is an increasing interest in the use of metal clusters stabilized in zeolites. One objective of such work is to utilize the shape and size constraints inherent in these support materials to effect greater selectivities in typical metal-catalysed reactions. Much work has been concerned with carbon monoxide hydrogenation, and although the detailed nature of the supported metals so obtained is not well understood, there is clear evidence of chain limitation in the Fischer-Tropsch process with both RuY zeolites and with HY and NaY zeolites containing Fe3(CO)22- In the former case there is a drastic decline in chain-growth probability beyond C5- or C10-hydrocarbons depending upon the particle size of the ruthenium metal. 

Dry, M.E. Present and future applications of the Fischer-Tropsch process. Applied Catalysis. A,... 

The history of the Fischer-Tropsch process has been adequately described in numerous articles, including two review papers by Storch (7) and Pichler (2) in Advances in Catalysis. We shall therefore refrain from repeating this exciting story here. It may suffice to mention the following highlights. 

Even more spectacular results in terms of the increasing importance of nanocatalysis for bulk industrial processes have recently been reported by Kuipers and de Jong [32, 33]. By dispersing metallic cobalt nanoparticles of specific sizes on inert carbon nanofibers the authors were able to prepare a new nano-type Fischer-Tropsch catalyst. A combination of X-ray absorption spectroscopy, electron microscopy, and other methods has revealed that zerovalent cobalt particles are the true active centers which convert CO and H2 into hydrocarbons and water. Further, a profound size effect on activity, selectivity, and durability was observed. Via careful pressure-size correlations, Kuipers and de Jong have found that or cobalt particles of 6 or 8nm are the optimum size for Fischer-Tropsch catalysis. The Fischer-Tropsch process (invented in 1925 at the Kaiser-Wilhelm-Institute for... 

In spite of such catalytic effects of the metal cluster, the rate of this reaction remains very low. Nevertheless, this reaction is an example of a very interesting type of homogeneous catalysis. Here the activation of carbon monoxide appears to be achieved by interaction of both the carbon and oxygen atoms with the metal cluster atoms in a similar way to the CO-chemisorption on metals in heterogeneous Fischer-Tropsch processes. 

Dry, M.E., 1996. Practical and theoretical aspects of the catal3ftic Fischer—Tropsch process. Applied Catalysis A 1996, 319—344. 

In more or less related reactions, Co2(CO)g is a useful catalyst in carboxylation (viz. alkoxycarbonylation) and a wide range of carbonylation reactions. Both catalysis of the water-gas shift reaction and of Fischer-Tropsch processes have been demonstrated on solid supports and probably involve Co2(CO)8-derived polynuclear carbonyls. ... 

The increase in industrial and academic research on Fischer-Tropsch catalysis following the Second World War and the oil crises of the 1970s is set to continue as the process is expected to become increasingly important... 

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