Herstellung von hydrolysestabilen Ammoniumsalzen sulfonierter Phosphite und deren Einsatz als Cokatalysatoren in der rhodiumkatalysierten Hydroformylierung

Hydrolytic Stable Ammonium Salts of Sulfonated Organic Phosphites and their Use as Cocatalysts in the Rhodium-catalyzed Hydroformylation of Olefins Ammonium salts of sulfonated organic phosphites, which are resistant to hydrolysis, have been prepared by transesterification of triphenylphosphite with mono-ammonium salt of p-hydroxyphenylsulfonic acid in yields between 66 and 76%. A mixture containing triisooctylammonium salts of sulfonated triphenylphosphite [TPPp-SO₃HN(i-octyl)₃] was submitted to a test for stability to hydrolysis. The time required for hydrolysis of 7.4% of the TPPp-SO₃HN(i-octyl)₃ was 3 hours under drastic conditions. Triphenylphosphite was in the same test hydrolyzed quantitatively within three hours. Tetradec-1-ene was hydroformylated by means of the catalytic systems consisting of rhodium-2-ethylhexanoate with either TPPp-SO₃HN(i-octyl)₃, triphenylphosphite (TPPp) or triphenylphosphine (TPP) at 125°C, 0.6 MPa and a rhodium concentration of 50 ppm. Higher reaction selectivities for linear aldehydes were achieved with the rhodium/TPPp-SO₃HN(i-octyl)₃ catalytic system. Reaction rates increased with the Rh/TPPp-SO₃HN(i-octyl)₃ catalyst at lower temperature (110°C). Using this catalyst at 110°C, higher yields are achieved than with the Rh/TPP or Rh/TPPp catalysts. Hex-1-ene was hydroformylated by using the catalytic systems Rh₄(CO)₁₂ with TPPp-SO₃HN(i-octyl)₃, Rh₄(CO)₁₂ TPP or Rh₄ (CO)₁₂ with TPPp at 125°C, 2,5 MPa and a rhodium concentration of 20 ppm. This confirms the above experiments which indicated that higher linear: branched aldehyde ratios were obtained with the rhodium/TPPp-SO₃HN(i-octyl)₃ catalyst.