摘要
研究了常压下铑簇络合物Rh_4(CO)_(12)催化烯烃氢甲酰化反应。结果表明,Rh_4(CO)_(12)本身在常压下没有催化活性,但与Ph_3P等某些叔膦化合物组成的体系具有较高的活性,其活性顺序为:PPh_3>P(C_6H_(11))_3>Ph_2P(CH_2)_3PPh_2>Ph_2P(CH_2)_2PPh_2>P(OPh)_3>Ph_2PCH_2PPh_2(=0)。催化活性和选择性与膦铑比有关。对苯乙烯而言,当P/Rh比为3时,活性最佳,TON达18min^(-1)以上;当P/Rh比为7.5时,生成2-苯基丙醛的选择性接近100％。溶剂也有显著影响,溶剂甲苯的结果最好。还考察了几种官能团烯烃的氢甲酰化反应。
The hydroformylation of different olefins under mild conditions (50℃, 1 atm.) has been investigated by using Rh4(CO)12 as catalyst precursor. Under these conditions, Rh4(CO)12 itself is not catalytically active, but it shows high activity in the presence of phosphines. In the case of PPh3, the catalyst activity increases with the increase of the ratio P/Rh at first, and passes to a maximum at P/Rh ratio of 3, and then decreases. For styrene, increasing the P/Rh ratio favors the formation of branched aldehyde, reversely, for octene, the high P/Rh ratio favors the formation of Straight chain aldehyde. Other phosphinc ligands can also be used instead of PPh3. The activities of catalysts for octene hydioformylation are in the order of PPh3>P(C6H11)3>Ph2P(CH2) 3PPh2 > Ph2P(CH2)2PPh2>P(OPh)3>Ph2PCH2PPh2( = 0). Although there is a decay of catalyst activity with time, high turnover nearly 4000 is still obtained for octene hydroformylation. Hydroformylation of olefins with different functional groups as Well as the effect of Solvent are also investigated.
基金
中国科学院科学基金
