A review of biphasic hydroformylation for long chain substrates

The regioselective hydroformylation reactions of long chain olefins catalyzed by different unmodified and modified Co-based, Rh-based catalysts are summarized. The mechanism of homogeneous hydroformylation reactions using Co-based/Rh-based catalysts (unmodified) showed inhibition of reaction rate due to higher partial pressure of CO and also caused difficulty in separating catalysts from the product mixture. Hydroformylation reactions in biphasic medium using water soluble catalysts (Rh, Co, Ru/TPPTS) with an effective surfactant, cetyltrimethylammonium bromide (CTAB), are discussed. The homogeneous biphasic systems are not applicable for long chain olefins due to their low solubility in aqueous phase.