摘要
提出了一类以五取代茂基稀土金属配合物与活性碱金属氢化物组成的加氢催化体系。实验表明:(C_5Me_4R)_2LnCl_2Li(THF)_2+MH(Ln=Nd,Yb,R=Pr;Ln=Gd,R=Me,Pr;M=K,Na)体系都能催化α-烯烃加氢,其活性较高,如(C_5Me_5)_2GdCl_2Li-NaH体系对1-己烯加氢TON可达40min^(-1)。碱金属氢化物的种类、THF以及温度等对其催化活性均有不同的影响。这类催化剂失活很快,其原因与反应体系中的烯烃有关。
A new type catalyst System, pentasubslituted cycJopentadienyl lanthanide complex-active alkali metal hydride for the hydrogenation of olefin was developed. (C5Me4R)2LnCl2Li(THF)2+MH(Ln = Nd, Yb, R = Pr, Ln= Gd, R = Me, Pr; M = K, Na) exhibits good activity for the hydiogenation of α-olefins, e.g. for hexenc-1 hydrogenation, the turnover number is about 40 min-1. The System containing KH has higher activity than NaH System, while LiH and MgH2 cannot act as a cocatalySt. It seems that the active species for the hydiogenation should be the organolanlhanide hydrides which can be formed in situ via the reaction between organolanthanide complex and NaH or KH. THF attached to the organolanthanide complex reduces the activity. Removal of THF from the complexes increases the catalyst activity, but the Solubility of the complexes without THF in toluene is smaller than that of the complexes with THF. The activity of the catalyst can be increased by treating the catalyst with supersonic wave.The Suitable temperature for the hydiogenation is about 40℃. The catalyst itself is stable under H2, its fast decay in activity is closely lelated to the presence of olefin.
基金
中国科学院科学基金
