Ruthenium-cobalt catalysts, iodide production

In a more detailed examination of the ruthenium-cobalt-iodide "melt" catalyst system, we have followed the generation of acetic acid and its acetate esters as a function of catalyst composition and certain operating parameters, and examined the spectral properties of these reaction products, particularly with regard to the presence of identifiable metal carbonyl species. 

It is clear that ruthenium-cobalt-iodide catalyst dispersed in low-melting tetrabutylphosphonium bromide provides a unique means of selectively converting synthesis gas in one step to acetic acid. Modest changes in catalyst formulation can, however, have profound effects upon liquid product composition. 

Data in Table V illustrate the production of acetic acid from 1/1 syngas. A variety of ruthenium-containing precursors - coupled with cobalt halide, carbonate and carbonyl compounds - at different initial Co/Ru atomic ratios, have been found to yield the desired carboxylic acid when dispersed in tetrabutylphosphonium bromide. In a more detailed examination of the ruthenium-cobalt-iodide melt catalyst system, we have followed the generation of acetic acid and its acetate esters as a function of catalyst composition and certain operating parameters, and examined the spectral properties of these reaction products, particularly with regard to the presence of identifiable metal carbonyl species. 

Alcohol Homologation Solvent and promoter effects on the cobalt carbonyl catalysed methanol homologation have been studied under synthesis gas pressure.The main product in a methanol/hydrocarbon two-phase system is 1,1-dimethoxyethane (ca. 70 selectivity).Using similar iodide promoted cobalt catalysts, R2C 0Me)2 and dimethylcarbonate are converted to acetaldehyde with up to 87 selectivity.Ruthenium in the presence of Co, 12 and dppe improves the ethanol selectivity in the homologation of dimethylether. Best results are achieved in inert solvents with high dielectric constants, e.g. sulfolane (e = 44), and with BF3 as activator. 

Carbohalogenation of various terminal or internal alkynes, via addition of perfluoroalkyl iodides or bomides, is catalyzed by carbonyl complexes of iron, cobalt or ruthenium. In this case, dichlorotris(triphenylphosphane)ruthenium(II) is not active as a catalyst. rram-Addition products are usually obtained in good yield under mild reaction conditions36. 

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