Hydroformylation and Carbonylation Reactions in Aqueous Biphasic Systems

1 Hydroformylation and Carbonylation Reactions in Aqueous Biphasic Systems 

The solubility of transition metal catalysts in water is determined by their overall hydrophilic nature, which may arise either as a consequence of the charge of the complex ion as a whole or may be due to the good solubility of the ligands. Examples of ionic organometallics soluble in water are 

The transition metal catalysts themselves are known to be stabilized by tertiary phosphines in their low oxidation states at one or more stages along the catalytic cycle. For this reason the most studied ligands in aqueous phase catalysis are derived from water-insoluble tertiary phosphines by installing on them ionic groups, typically sulfonate, but also sulfate, phosphonate, carbox-ylate, quaternary ammonium, phosphonium, as well as neutral polyether or polyamide substituents, etc. 

Rh(i) complex in water and its insolubility in butanal, the plant unit is essentially reduced to a continuous stirred tank reactor followed by a phase separator (decanter) and a stripping column. Propene and syngas are initially added to the catalyst containing aq. solution, then, once the reaction has taken place, the reaction products and the catalyst phase pass into the decanter, where the aqueous catalyst solution and the butanal phase are separated. 

Apart the use of water as solvent and the excellent atom economy of the process, the ecological benefits of the RCH/RP process with respect to the classic ones can be summarized as follows  

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