Acta Phys. -Chim. Sin. ›› 1996, Vol. 12 ›› Issue (01): 71-74.doi: 10.3866/PKU.WHXB19960116

• Note • Previous Articles     Next Articles

in situ 1H NMR Study of Active Species of Hydroformylation Catalyst

Li Da-Gang,Xia Chun-Gu,Sun Yan-Wen,Yang Wei-Man   

  1. Lanzhou Institute of Chemical Physics Academic Sinica,Lanzhou 730000
  • Received:1994-12-02 Revised:1995-06-07 Published:1996-01-15
  • Contact: Li Da-Gang

Abstract:

The rhodium-phosphine complex catalyst Rh(CO)(acac)(PPh3)(Ⅰ) for 1-hexene hydroformylation was studied under the following reaction conditions: CO/H2=1(mole rate), pressure 1.0 MPa, temperature 25-120℃, by using the pressurized in-situ 1H NMR technique. Experimental results indicated that the formation of a rhodium hydride complex from (Ⅰ) began at room temperature and its amount increased with increasing of reaction temperature. This intermediate complex began to decompose at 100℃ and disapeared completely at 120℃. The intensity change of the proton signal was parallel to catalytical activity in hydroformylation of olefins. Under pure CO pressure the proton signal of Ph-H bond was not observed. There was a 0.2 ppm difference in proton chemical shifts of Rh-H bond under pure H2 pressure and under H2+CO pressure. The results showed that the rhodium-hydride carbonyl complex is the active intermediate in the industrial hydroformylation process.

Key words: Hydroformylation catalyst, Olefin hydroformylation, Active species, in-situ NMR