硅胶固载Ru(Ⅱ)Cl_2(PPh_3)_3催化苯乙酮不对称加氢

Asymmetric hydrogenation of acetophenone catalyzed by RuCl_2(PPh_3)_3 immobilized on amorphous silica

通过共价键联的方法将RuCl_2(PPh_3)_3配合物固载于手性二胺修饰的硅胶表面,制备了多相不对称加氢催化剂。采用等离子体发射光谱(ICP)、红外光谱(FTIR)和紫外光谱(UV—Vis)等手段对制备的催化剂进行了表征。结果表明,RuCl_2(PPh_3)_3配合物固载于硅胶表面保持了原有的结构性能。在苯乙酮不对称加氢反应中,不同手性二胺对催化反应具有明显的影响,(1S,2S)-1,2-二苯基乙二胺的手性诱导能力强于其他二胺,优化条件下,苯乙酮转化率达100%,(R)-苯乙醇的对映体过量值达50%,固体催化剂具有良好的稳定性和重复使用性。

A series of solid asymmetric heterogeneous catalysts were prepared through the immobilization of RuCl2 （PPh3 ）3 complex on the surface of amorphous silica, which was modified with chiral diamine, and characterized by ICP, VFIR and UV-Vis. The results showed that RuCl2 （ PPh3 ） 3 immobilized on the surface of amorphous silica kept their original structure properties. Using RuCl2 （ PPh3 ）2 immobilized on amorphous silica as asymmetric hydrogenation catalysts, the conversion of acetophenone and the enantiomeric excess value of （R）-pheny｜ethanol were attained 100% and 50%, respectively. The catalysts exhibited good stability and repeatable without loss of activity and ee value.