新型离子液体介质中长链烯烃氢甲酰化反应

合成和表征了离子液体[Rmim][p-CH3C6H4SO3](R=CH3(CH2)n—, n=3, 7, 11, 15), 并以所合成的离子液体为反应介质, 考察了水溶性铑膦络合物HRh(CO)(TPPTS)3[TPPTS: P(m-C6H4SO3Na)3]对长链烯烃氢甲酰化反应的催化性能. 结果表明, 离子液体[Rmim][p-CH3C6H4SO3]中R基团链长的变化对催化活性具有重要的影响；而在相同离子液体中, 氢甲酰化反应活性随着烯烃链长的增加明显下降. 与文献报道中广泛使用的离子液体[Bmim]BF4、[Bmim]PF6相比, 该催化体系对长链烯烃氢甲酰化反应具有更好的活性和化学选择性, 在3.0 MPa, 100 ℃的条件下, 1-己烯氢甲酰化反应转化频率(TOF)高达2736 h-1. 反应完成后, 水溶性铑膦络合物能很好地溶解在离子液体中, 与有机物自动分层, 催化剂的循环使用易于实现.

Hydroformylation of Long-chain Olefins Catalyzed by Rhodium-Phosphine Complexes in New Ionic Liquids

Preparation and characterization of a series of halogen-free ionic liquids 1-alkyl-3-methyl-imidazolium p-tolusulfonate([Rmim][p-CH3C6H4SO3], R= n-butyl, n-octyl, n-dodecyl, n-cetyl) were reported. These halogen-free ionic liquids were applied as a reaction medium in the hydroformylation catalyzed by water-soluble rhodium complex HRh(CO)(TPPTS)3[TPPTS: P(m-C6H4SO3Na)3]. The results showed that the activity of the hydroformylation was related with the chain-length of R-group in ionic liquids [Rmim][p-CH3C6H4SO3] and decreased with the increase of chain-length of higher olefins. Compared with the halogen-containing anologues [Bmim]BF4 and [Bmim]PF6, the hydroformylation of higher olefins in ionic liquids [Rmim][p-CH3C6H4SO3] exhibited higher activity and selectivity for the aldehydes. Under moderate reaction conditions, the catalyst turnover frequency of 1-hexene hydroformylation as high as 2736 h-1 has been observed. Moreover, the products were conveniently separated from the catalyst by simple decantation and the rhodium-phosphine complexes immobilized in the ionic liquids could be reused several times without significant loss of activity and selectivity. The rhodium leaching into the organic product was lower than 0.1%.