P/Rh比对PPh_3-Rh/SiO_2催化剂上丙烯氢甲酰化反应的影响

Influence of Phosphine Concentration on Propylene Hydroformylation over the PPh_3-Rh/SiO_2 Catalyst

研究了P/Rh比对PPh3-Rh/SiO2催化剂上丙烯氢甲酰化反应性能的影响.结果表明,当P/Rh比为15时,丙烯氢甲酰化反应性能最好,丙烯转化率为25.9%,产物丁醛正异比为14,转换频率为241h-1.PPh3-Rh/SiO2催化剂的固体31P核磁共振结果表明,在合成气气氛下,物理吸附的PPh3能够溢流到Rh/SiO2表面形成化学吸附的PPh3,从而促进了具有氢甲酰化活性的铑膦络合物的形成.Wilkinson催化平衡理论也很好地解释了本实验结果.

The effect of triphenyl phosphine concentration in the novel PPh3-Rh/SiO2 catalyst for propylene hydroformylation was studied and found an optimum P/Rh ratio of 15,a butyraldehyde n/i ratio of 14,a butyraldehyde TOF of 241 h-1,and high catalytic stability for PPh3-Rh/SiO2.Solid-state 31P NMR shows that in an atmosphere of syngas the physically adsorbed PPh3 migrates onto the surface of Rh/SiO2 where it chemically adsorbs and then promotes the in situ formation of carbonyl phosphine complexes.