| abstract |
Certain triarylphosphine rhodium carbonyl hydride complexes (I) and (II) are selective and stable catalysts for the high temperature hydroformylation of olefins. The critical factors are the maintenance of a sufficient partial pressure of CO, greater than 25 psia, as well as a strongly excess concentration per ligand of triarylphosphine, at a minimum of 1 mole per kg. In order to obtain a high ratio between the n-aldehyde products and the i-aldehyde products of the hydroformylation of 1-olefin, the concentration of the tris-phosphine complex (I) is made maximum. In a continuous operation of the present process consisting in instant drying of the product, the main components of the high boiling solvent are the excess phosphine ligands, as well as the mono-alcohol and mono-ester derivatives. A combined isomerization and hydroformylation process is also described for the selective conversion of internal linear olefins to terminal n-aldehydes. In this process, the concentration of the bis-phosphine (II) complex is made minimal. By contrast, the maximum concentration of the bis-phosphine complex is rendered in a process converting internal linear olefins into corresponding branched i-aldehydes. |