First efficient catalyst recycling for the iridium-catalysed hydroformylation of 1-octene

This paper describes the development of an efficient catalyst recycling concept for the iridium-catalysed hydroformylation of 1-octene through the investigation of biphasic systems, thermomorphic solvent systems and an ex situ extraction. Particularly high selectivities (>90%) towards the desired aldehydes as well as low rates of iridium leaching were observed using the monosulfonated triphenylphosphine ligand (TPPMS). In polar solvents such as propylene carbonate or N, N-dimethylformamide, low rates of catalyst leaching (0.2%) as well as high rates of product separation (nearly 80%) were achieved. High reaction rates and a long-term activity and stability of the catalyst were observed using the solvent N, N-dimethylformamide and the extraction with non-polar solvents.