Hydroformylation, Fischer-Tropsch synthesis

Reduction of CO and ketones Hydroformylation Fischer-Tropsch synthesis Synthesis of methanol from CO Hydrogenation of amides Alkyne cycUzation Hydroxymethylation... 

Q Fischer-Tropsch Synthesis and Hydroformylation on Cobalt Catalysts The Thermodynamic Control... 

Comparing heterogeneous Fischer-Tropsch synthesis with homogeneous olefin hydroformylation can be seen as a source for understanding catalytic principles, particularly because the selectivity is complex and therefore highly informative. Reliable analytical techniques must be readily available. 

During a study of the origin of oxygenates in Fischer-Tropsch synthesis in the presence of a cobalt catalyst, Roelen observed the formation of propanal and 3-penta-none when ethylene was added to the feed.1 The process now termed hydroformylation or oxo reaction is the metal-catalyzed transformation of alkenes with carbon monoxide and hydrogen to form aldehydes ... 

Commercial isobutyl alcohol is made almost exclusively from the hydrogenation of isobutyraldehyde obtained by the hydroformylation of propylene. However, this alcohol is also commonly obtained as a coproduct in the Fischer Tropsch synthesis of methanol (16,17). 

Transition metal carbonyls and their derivatives are remarkably effective and varied in their ability to catalyze reactions between unsaturated molecules (e.g., CO and olefinic compounds) or between certain saturated and unsaturated molecules (e.g., olefins and H2 or H20). The carbonyl derivatives of cobalt are particularly active catalysts for such reactions and have been put to use in the industrial synthesis of higher aliphatic alcohols. In fact, much of the growth in knowledge concerning catalysis by metal carbonyls has been stimulated by the industrial importance of the Fischer-Tropsch synthesis, and by the economically less important, but chemically more tractable, hydroformylation reaction. 

In summary, cluster-derived catalysts have been widely used in various types of CO-based reactions such as Fischer-Tropsch synthesis, methanol synthesis, hydroformylation, carbonylation, and water-gas shift reactions. The catalytic performances of cluster-derived species are evaluated in terms of higher activities and selectivities for lower olefins and oxygenates in CO hydrogenation, compared with those of metal complexes in solution and conventional metal catalysts (Table XIII). 

When a fluid is compressed and heated above the critical conditions (or to supercritical conditions, sc), the differences between gas and liquid disappear. For carbon dioxide, this occurs for temperatures above 31 °C and pressures above 7.3 MPa. For reactions (such as alkylations, aminations, hydroformylations, hydrogenations and Fischer Tropsch synthesis) occurring in supercritical fluids, the reaction rate is often increased dramatically because of improved desorption of heavy molecules minimizing the oxygen and hydrogen solubility limitations, improved heat transfer, and improved selectivity by a catalyst by minimizing pore diffusion limitations. 

Heterogenized clusters are used as catalysts for many reactions, for instance, the Fischer-Tropsch synthesis, the water-gas shift reaction, hydroformylation, hydrogenation, polymerization, oligomerization, isomerization, etc. In the case of the Fischer-Tropsch synthesis, catalysts that are prepared from clusters often show considerably higher selectivity than other catalysts. 

Hydroformylation is the reaction of an unsaturated compound (or a saturated compound which may generate an unsaturated compound) with carbon monoxide and hydrogen to yield an aldehyde. The reaction was discovered by O. Roelen in the laboratories of Ruhrchemie AG, Oberhau-sen-Holten in 1938 [21-23] when he tried to recycle olefins to the Fischer-Tropsch synthesis reactor. As reaction products he isolated oxygen-containing compounds which proved to be aldehydes and ketones. Roelen started extensive investigations with ethylene and obtained propionalde-hyde and diethylketone as main products. 

Hydroformylation was discovered in 1938 at the company Ruhrchemie in Ober-hausen, Germany by Otto Roden (1897-1993) in the context of investigations to optimize the Fischer-Tropsch synthesis (FT synthesis) for fuel production from coal based syngas (Section 6.11.1). Otto Roden realized at the time that the formation of C3-oxoproducts in the FT synthesis was due to the reaction of ethylene with syngas. 

Syn gas is also used to produce methanol, to produce hydrocarbons by the Fischer-Tropsch synthesis and to react with olefins in the synthesis of aldehydes and alcohols by hydroformylation. For the synthesis of methanol, syn gas is reacted, typically with a copper-based catalyst to form methanol by the following equation. 

Synthesis gas is an important intermediate. The mixture of carbon monoxide and hydrogen is used for producing methanol. It is also used to synthesize a wide variety of hydrocarbons ranging from gases to naphtha to gas oil using Fischer Tropsch technology. This process may offer an alternative future route for obtaining olefins and chemicals. The hydroformylation reaction (Oxo synthesis) is based on the reaction of synthesis gas with olefins for the production of Oxo aldehydes and alcohols (Chapters 5, 7, and 8). 

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