Heteropolyacids enhanced the catalytic activity of Rh6(CO)16 in the hydroformylation of alkenes

Active homogeneous catalytic systems based on Rh₆(CO)₁₆‐heteropolyacids for the regioselective hydroformylation of styrene and 1‐octene and their derivatives have been developed. The effects of the amount and the type of the heteropolyacid have been studied and showed a significant improvement of the conversion of styrene and the selectivity towards branched aldehydes. Other rhodium complexes were also considered in the study and the results showed the advantages of the rhodium cluster Rh₆(CO)₁₆ associated with the heteropolyacid H₃PW₁₂O₄₀,25H₂O (HPA‐W₁₂). The effects of temperature, type of solvent and CO/H₂ pressure have also been considered in order to optimize the reaction conditions. Copyright © 2004 John Wiley & Sons, Ltd.