NOVEL WATER-SOLUBLE CATALYSTS FOR HYDROGENATION OF OLEFINS AND LOW-MOLECULAR-WEIGHT POLYMERS IN AQUEOUS AND AQUEOUS ORGANIC BIPHASIC MEDIA/

A series of carboxylated phosphines of the type Ph(2)P-(CH2)(n)-CO2Na, where n = 1, 2, 4, 5, and 7, and p- or m-Ph(2)P-C6H4-CO2Na have been synthesized. The ligands are readily soluble in water. The water solub le complexes [RhCl(HEXNa)(2)](2), 1 (HEXNa = Ph(2)P-(CH2)(5)-CO2Na), a nd [RhCl(OCTNa)(2)](2), 2 (OCTNa = Ph(2)P-(CH2)(7)-CO2Na), have been p repared by the general reaction of exchange of PPh(3), in RhCl(PPh(3)) (3) with HEXNa or OCTNa ligands. A similar phosphine exchange reaction with Ph(2)P-(CH2)-CO2Na (NaA) led to a water insoluble complex which is formulated as Rh(PPh(3))A(NaA), 3, in which NaA acts as a P-monoden tate and A(-) as a P,O-chelating ligand. Complexes 1 and 2 were found to be effective catalysts for hydrogenation of olefins and polybutadie ne in aqueous and aqueous/organic biphasic media, respectively. With b oth catalysts the terminal olefins were hydrogenated much faster than the internal olefins, but an unusually enhanced hydrogenation rate was observed in the hydrogenation of the internal double bonds in 2-pente ne- and 3-pentenenitriles. The catalysts show selectivity for the hydr ogenation of 1,2 (vinyl) addition units over 1,4 (internal) addition u nits present in the polybutadiene.