B. Fell et G. Papadogianakis, RHODIUM-CATALYZED 2-PHASE HYDROFORMYLATIO N OF HEX-1-ENE WITH SULFONATED TRIS(4-FLUOROPHENYL)PHOSPHINE AS WATER-SOLUBLE COMPLEX LIGANDS, Journal fur praktische Chemie, Chemiker-Zeitung, 336(7), 1994, pp. 591-595
Tris(4-fluorophenyl)phosphine (TFPP) was prepared from 1-bromo-4-fluor
o-benzene in 35% yield. This phosphine was quantitatively sulfonated b
y 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 th
e trisulfonated tris(4-fluorophenyl)phosphine (TFPPTS). After 410 hour
s of sulfonation, hydrolysis and pH-selective separation, the resultin
g mixture contained 6% TFPPTS and 94% disodium salt of the disulfonate
d 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) w
ith the trisodium salt of trisulfonated triphenylphosphine (TPPTS). Th
e TFPP or TFPPTS ligand possesses a stronger pi-acidity than the TPP o
r TPPTS and at low P/Ph-ratios higher selectivities to linear aldehyde
s 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 q
uantitatively recovered by simple separation of the aqueous layer from
the organic layer which contains the substrate and the products.