RHODIUM-CATALYZED 2-PHASE HYDROFORMYLATION OF HEX-1-ENE WITH SULFONATED TRIS(4-FLUOROPHENYL)PHOSPHINE AS WATER-SOLUBLE COMPLEX LIGANDS

Tris(4-fluorophenyl)phosphine (TFPP) was prepared from 1-bromo-4-fluoro-benzene in 35% yield. This phosphine was quantitatively sulfonated by using a H2SO4- SO3 mixture containing 25,5% SO3 and a 14-fold excess of SO3 to phosphine. The desired product was the trisodium salt of the trisulfonated tris(4-fluorophenyl)phosphine (TFPPTS). After 410 hours of sulfonation, hydrolysis and pH-selective separation, the resulting mixture contained 6% TFPPTS and 94% disodium salt of the disulfonated tris(4-fluorphenyl)phosphine (TFPPDS). Hex-1-ene was hydroformylated in a two-phase system by using the water-soluble catalytic systems Rh-4(CO)(12) with a mixture of 94% TFPPDS + 6% TFPPTS and Rh-4(CO)(12) with the trisodium salt of trisulfonated triphenylphosphine (TPPTS). The TFPP or TFPPTS ligand possesses a stronger pi-acidity than the TPP or TPPTS and at low P/Ph-ratios higher selectivities to linear aldehydes are achieved with the Rh/TFPP or Rh/TFPPDS + TFPPTS than with the Rh/TPP or Rh/TPPTS catalytic system. The Rh/TFPPDS + TFPPTS complex is quantitatively recovered by simple separation of the aqueous layer from the organic layer which contains the substrate and the products.