Biphasic hydroformylation of 1-octene catalyzed by ionic Rh(III)-complex in the presence of tertiary amine functionalized ionic liquid

The ionic Rh(III)-complexes 1a and 2a exhibited poor catalytic performance for hydroformylation of 1-octene without the presence of any auxiliary additive. The involvement of cheap and low-toxic tertiary amines such as Et₃N or N-methylpiperidine could dramatically boost the catalytic performance of compounds 1a and 2a up to turnover frequency (TOF) of 800 h^-1. When piperidinyl-functionalized ionic liquid of [PEmim]BF₄ was dually used as the additive and the solvent, not only the positive roles of N-methylpiperidine in spurring up the activity of compounds 1a and 2a were embodied, but also the easy recovery and recycling of compounds 1a(or 2a) in [PEmim]BF₄ were fulfilled in biphasic hydroformylation. The TOFs of compounds 1a and 2a in [PEmim]BF₄ were gradually decreased in the course of the recycling uses due to the leaching and deactivation of the catalysts.