Catalytic carbonylation reaction

Hydroformylation. Probably the best known catalytic carbonylation reaction is the hydroformylation, or 0x0 reaction, for producing aldehydes and alcohols from carbon monoxide, hydrogen, and olefins (eq. 9) (36). 

From the temperature variation of the equilibrium constant, thermodynamic parameters for the reaction were also obtained. The extent of formation of [Mo(CO)5l]" was found to be cation-dependent, and while equilibrium constants of 39 and 21 atm L moF were obtained for Bu4P and pyH+, none of the anionic iodide complex was observed for Na. Despite this variation, there seemed to be no correlation between the concentration of [Mo(CO)5l]" and the rate of the catalytic carbonylation reaction. It was proposed that [Mo(CO)5] and [Mo(CO)5l] are spectator species, with the catalysis being initiated by [Mo(CO)5]. Based on the in situ spectroscopic results and kinetic data, a catalytic mechanism was suggested, involving radicals formed by inner sphere electron transfer between EtI and [Mo(CO)5]. 

HRu(CO)s] is an interesting complex and has potential for a number of catalytic carbonylation reactions. However, the evidence for the presence of hydrogen is based mainly on chemical analysis which consistently shows the small hydrogen content. The stoichiometric carbonylation according to Reaction 4 and the IR of the crude carbonyl are... 

A pyridine-2-carboxylato (N-0) complex of palladium(II) with a labile tosylato ligand has been shown to act as an efficient carbonylation catalyst for a series of alcohols and olefins. The catalyst precursor, [Pd(N-0)(0Ts)(PPh3)] (24), in conjunction with promoters (e.g. Lil, LiCl, TsOH), is active for the carbonylation of primary, secondary and tertiary alcohols as well as functionahzed terminal olefins with good selectivity and turnover frequency. This reaction has been further discussed in a report dealing with the kinetic modeling of this and other catalytic-carbonylation reactions. 

As mentioned earlier, acyl derivatives of transition metals are probably intermediates in some catalytic carbonylation reactions involving molecular hydrogen. Significantly, tertiary phosphine-substituted acyl derivatives of cobalt(I) react with Hj at elevated pressure and ambient temperature in pentane to give aldehydes ... 

In these catalytic carbonylation reactions, metallic palladium and hydrogen halides are essential for the catalysis. Furthermore, olefins react with carbon monoxide and hydrogen in benzene in the presence of metallic palladium to form aldehydes in a low yield (19). 

Monsanto acetic acid synthesis 4), and the hydroformylation or 0X0 reaction (5). A key mechanistic step in catalytic carbonylation reactions is the migration of an alkyl group onto an adjacent carbonyl ligand. This reaction involves the formation of a new carbon-carbon bond and has been termed a carbonyl insertion reaction since a CO ligand has been formally inserted into the transition metal-carbon (r-bond. Because of the industrial and commercial importance of these catalytic reactions, the search for stoichiometric systems in which this step can be observed directly has been, and still is, one of great endeavor. 

Catalytic Carbonylation Reactions Volume Editor M. Beller Vol. 18, 2006... 

Although in all of Geoffroy s papers it was always remarked that no firm evidence existed that the reactions reported were of any relevance to the actual catalytic cycle, this prudent statement is not always found in other authors papers and seems anyway to have been overlooked by many readers, so that the involvement of imido clusters as intermediates in the catalytic carbonylation reactions of nitro-arenes catalyzed by Ru3(CO)i2 seems now to be taken for granted by many researchers in the field. 

An important point, difficult in many cases to be clarified, is related to the nature o-f the catalytic system, that is which is the real catalytical 1y active species and moreover in which cases we can clearly distinguish between homogeneous and heterogeneous catalysis. For these reasons, the subdivision between heterogeneous(4,2.5.1., 4.2.6.1.) and homogeneous (4.2.5.2., 4.2,5.3., 4.2.6.2.) catalysts is in some cases somewhat arbitrary and uncertain. This unsatisfactory situation is primarily due to the fact that with few exceptions the catalytic carbonylation reactions of nitro compounds proceed at high pressures and temperatures, and these are reaction conditions which interfere with studies on the mechanism of these reactions. 

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