Hydroformylation with Dendritic-Polymer-Stabilized Rhodium Colloids as Catalyst Precursors

Hydroformylation of 1‐hexene with rhodium colloids stabilized by poly(ethylene imine) amides with a hyperbranched polyamine core and a lipophilic periphery is reported. The catalyst selectivity for aldehydes increases with increasing temperature or pressure. The ratio of linear to branched aldehydes decreases with increasing temperature. At 80 °C and 90 atm, 1‐hexene is converted completely with 96% selectivity for aldehydes, with a ratio of linear/branched aldehydes of 58:42. Turnover numbers up to 3 × 104 (calculated with respect to the entire amount of Rh present) were observed. The results indicate that the catalyst precursor colloids serve as a reservoir for the formation of soluble Rh(I) complexes as the active species.