Carbon monoxide carbonyl-phosphine rhodium

Hydroformylation of PhCH=CHMe in the presence of RhCl(PPh3)3 produces PhCH(CHO)-CHa-CH3 and PhCH3-CH(CHO)-CH3, as well as some PhCH2 CH2 CH3. Both Rh4(CO)i2 and mixed carbonyl-phosphine complexes derived from Rh4(CO)i2 and from Rh,(CO)ie are active catalysts for hydroformylation of alkenes. Acyl-rhodium intermediates may be important when Rh4(COX2 is the catalyst, for [Rh-(C0)2(02CR)]2 dimers have been isolated from alkene hydroformylations in which this polynuclear carbonyl has been the catalyst. Rh4(CO)i2 also catalyses the reaction between ethylene and carbon monoxide, which produces several products, including octane-3,6-dione, undecane-3,6,9-trione, and tetradecane-3,6,9,12-tetraone. The products obtained indicate a mechanism in which addition of ethylene to rhodium and insertion of carbon monoxide into a rhodium-carbon bond alternate. ... 

To make butyraldehyde, the precursor for NBA, the so-called Oxo process is used, reacting chemical grade propylene with hydrogen and. carbon monoxide at 250-300°F and 3500-4000 psi. See Figure 14-4.) Under those conditions, both feeds are liquids. The catalyst is an oil-soluble cobalt carbonyl complex dissolved in the propylene. If rhodium-based catalysts or complexes based on rhodium carbonyls and triphenyl phosphine... 

The effect of tin compounds, especially tetra-alkyl and tetra-aryl tin compounds, is similar to that of phosphine, though lower temperature and pressure are required for the catalyst s optimum activity. Tin can promote the activity of the nickel catalyst to a level that matches that of rhodium under mild conditions of system pressure and temperature e.g. 400 psig at 160 C. The tin-nickel complex is less stable than the phosphine containing catalyst. In the absence of carbon monoxide and at high temperature, as in carbonyl-ation effluent processing, the tin catalyst did not demonstrate the high stability of the phosphine complex. As in the case of phosphine, addition of tin in amounts larger than required to maintain catalyst stability has no effect on reaction activity. 

Patents on the carbonylation of methyl chloride [74-87-3] using carbon monoxide [630-08-0] in the presence of rhodium, palladium, and ridium complexes, iodo compounds, and phosphonium iodides or phosphine oxides have been obtained (26). In one example the reaction was conducted for 35... 

Halogeno-carbonyl and -phosphine complexes. I.r. spectral studies at elevated CO pressures have indicated that carbon monoxide, like other Lewis bases, is capable of bridge splitting in rhodium dicarbonyl halides, as in reaction (15). ... 

The important discovery by Wilkinson [1] that rhodium afforded active and selective hydroformylation catalysts under mild conditions in the presence of triphenylphosphine as a hgand triggered a lot of research on hydroformylation, especially on hgand effects and mechanistic aspects. It is commonly accepted that the mechanism for the cobalt catalyzed hydroformylation as postulated by Heck and Breslow [2] can be apphed to phosphine modified rhodium carbonyl as well. Kinetic studies of the rhodium triphenylphosphine catalyst have shown that the addition of the aUcene to the hydride rhodium complex and/or the hydride migration step is probably rate-limiting [3] (Chapter 4). In most phosphine modified systems an inverse reaction rate dependency on phosphine ligand concentration or carbon monoxide pressure is observed [4]. 

A catalytic decomposition of triphenylphosphine has been reported [26] in a reaction involving rhodium carbonyls, formaldehyde, water, and carbon monoxide. Several hundreds of moles of phosphine can be decomposed this way per mole of rhodium per hour The reactions that may be involved are shown in Figure 9. 

The catalytic hydrocarbonylation and hydrocarboxylation of olefins, alkynes, and other TT-bonded compounds are reactions of important industrial potential.Various transition metal complexes, such as palladium, rhodium, ruthenium, or nickel complexes, have widely been used in combination with phosphines and other types of ligands as catalysts in most carbonylation reactions. The reactions of alkenes, alkynes, and other related substrates with carbon monoxide in the presence of group VIII metals and a source of proton affords various carboxylic acids or carboxylic acid derivatives.f f f f f While many metals have successfully been employed as catalysts in these reactions, they often lead to mixtures of products under drastic experimental conditions.f i f f f In the last twenty years, palladium complexes are the most frequently and successfully used catalysts for regio-, stereo-, and enantioselective hydrocarbonylation and hydrocarboxylation reactions.f ... 

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