Catalysis Today, Vol.74, No.1-2, 85-90, 2002
Thermoregulated phase transfer ligands and catalysis - Part XIII. Use of nonionic water-soluble phosphine ligands to effect homogeneous catalyst separation and recycling
Nonionic tensioactive water-soluble phosphines that act as ligands for rhodium-catalyzed hydroformylation of higher olefins under aqueous-organic biphasic conditions are described with emphasis on the recycling efficiency of homogeneous catalyst. Phosphines discussed are P-[p-C6H4(OCH2CH2),OH](3) (1a: N = 3n = 18, 1b: N = 3n = 25) and Ph2P-[p-C6H4(OCH2CH2)(n)OH] (2a: N = n = 16, 2b: N = n = 25) (PEO-TPPs). The rhodium catalyst combined with these ligands gave an average turnover frequency (TOF) of 182h(-1) for 1-hexene. More importantly, recovery and reuse of catalyst is possible because of the inverse temperature-dependent water solubility of the phosphines.
Keywords:nonionic phosphine;homogeneous catalyst;environmentally benign catalysis;separation;hydroformylation