Cobaltate, complex with water soluble phosphine

Other cationic pentacoordinate organocobalt complexes have been investigated, such as those obtained with water-soluble phosphines P[(CH2) C6H4- -S03Na]3 ( = 1, 2, 3, and 6). This type of phosphines reacted rapidly with Co2(CO)g in two-phase reaction conditions to yield the disproportionation products [Co(CO)3(P[(CH2) C6H4-/>-S03Na]3)2][Co(CO)4]. This series of complexes has been used as precursors to water-soluble cobalt hydroformylation catalyst. ... 

It is interesting to note that no specific study was devoted to the aqueous biphasic hydrogenation of aldehydes with water-soluble cobalt-phosphine complexes, although such a property has long been known from hydroformylation experiments [199,200]. 

In the first stage, 1-butene is preferentially converted to valeraldehyde. This takes place in a low-pressure process, in which the catalyst used is a rhodium complex compound containing water-soluble phosphines as ligands. A solubilizer is also added. In the second stage, the 2-butene not converted in the first stage is hydroformylated with a cobalt catalyst. Part of the valeraldehyde obtained is then hydrogenated to amyl alcohol [109]-[111]. 

The selectivity to linear product is improved by using a cobalt trialkyl phosphine complex, but the major product is the corresponding alcohol. The use of rhodium triphenylphosphine hydrocarbonyl gives a still higher selectivity to linear aldehyde under milder conditions. These advantages are retained by using a water-soluble rhodium complex with sulphonated phosphane ligands, which provides a novel two-phase mode of operation (recently commercialized). ... 

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