Aqueous-Phase Hydroformylation of 1-Octene: Styrene Latices as Phase-Transfer Agents

摘要

The Co- and Rh-catalyzed hydroformylation of olefins to aldehydes has become one of the most important commercial applications of homogeneous catalysis. However, one of the major problems is the catalyst recovery from the reaction mixture. A commercial solution was applied in 1984 with the RCH/RP process,[1] which is an aqueous-phase hydroformylation that converts propene to n-butyraldehyde (ca. 0.8 Mt a-1) and isobutyraldehyde in the presence of [HRh(CO)(tppts)3] (see Scheme 3 for tppts). The modified rhodium catalyst is dissolved in the aqueous phase, and propene is significantly soluble in water. Thus, the catalyst is recovered without any significant loss by separation of the organic product layer from the aqueous phase. However, the process is limited to olefins with short alkyl chains since the solubilities of olefins in water decrease with increasing number of carbon atoms, and the hydroformylation is therefore limited by the rate of mass transfer. Thus, higher olefins (>C6) are not suited for the RCH/RP process.