Hydroformylation of olefins catalysed by (1,5-cyclooctadiene) salicylaldoximatorhodium under atmospheric pressure

Abstract

Hydroformylation of vinylarenes, alkenes and cyclic olefins has been investigated using (1,5-cyclooctadiene) salicylaldoximatorhodium (Rh(SOX)(COD)) as catalyst precursor at 0.1 MPa and 60°C in toluene. It has been found that the anionic salicylaldoximato chelate ligand plays an important role in determining the hydroformylation activity under mild conditions. The reaction rate and regio-selectivity also depend on the phosphine or phosphite ligands added. The combination of Rh(SOX) (COD) with diphosphine ligands is the more active in the hydroformylation of vinylarenes, but those with monophosphine ligands are favoured in the hydroformylation of alkenes. The use of diphosphine increases the formation of branched aldehydes both in the hydroformylation of vinylarenes and alkenes. Increasing the phosphine concentration results in a decrease of the catalytic activity, but the regioselectivity almost keeps constant in all cases.