Promising Applications of Polyethyleneimine as a Ligand in Rhodium-Catalyzed Tandem Hydroformylation/Hydrogenation of Olefins.

Three rhodium-containing catalytic systems active in tandem hydroformylation/hydrogenation of unsaturated substrates were developed based on polyethyleneimine (PEI): a homogeneous system with distillation of the product; a biphasic system with segregation of the product and catalyst into a non-polar phase and a polar phase, respectively; and a solid catalyst prepared from PEI and (3-chloropropyl)triethoxysilane with its centrifugation from the product mixture. All the systems were shown to be reusable over multiple cycles in hydroformylation/hydrogenation, with the catalytic activity being partially sustained in both steps of the tandem process. Methylation of PEI (or its NH and NH₂ moieties in the case of solid material) was found to be critical for the catalytic activity in hydroformylation. [ABSTRACT FROM AUTHOR]