Behaviour of water-soluble dinuclear rhodium complexes in the hydroformylation reaction of oct-1-ene

Article abstract of DOI:10.1016/0022-328X(94)87115-9

The biphasic hydroformylation reaction of oct-1-ene, has been investigated by using the water-soluble dinuclear complex tBu)2(CO)2(TPPTS)2> as precursor.Addition of ethanol as a cosolvent dramatically improved the yields but the good regioselectivity in linear aldehyde observed for neat oct-1-ene-water systems (97percent) decreased to 83percent (for 22percent ethanol w/w).It is shown that the dinuclear framework cannot be maintained,that the mononuclear complex is formed, and that thiol and significant amounts of tBu)2(CO)4> move into the organic phase.This reaction from the dinuclear species requires the simultaneous presence of water and carbon monoxide.Introduction of the water-soluble thiol HS(CH2)3NMe2 in the bridging positions affords the complex Cl2 which can be kept in the aqueous phase but has a low level of catalytic activity. Key words: Rhodium; Hydroformylation; Alkenes; Biphasic catalysis