摘要
研究了奎宁作手性修饰剂修饰的负载型纳米铑簇合物催化剂 (Rh/ PVP-γ-Al2 O3)催化丙酮酸乙酯不对称氢化反应 ,在该反应中手性修饰剂奎宁不仅具有手性诱导作用 ,而且还有明显加速反应的作用 ;载体γ-Al2 O3在促进提高催化剂活性和对映选择性方面也有很重要的影响 .在优化的反应条件 [2 0℃ ,7.0 MPaH2 ,c(奎宁 ) =3 .86× 1 0 - 3mol/ L,四氢呋喃作溶剂 ]下 ,丙酮酸乙酯不对称加氢的转化频率 (TOF)为871 h- 1 ,对映选择性达到了 5 4.7% ;反应温度降低到 3℃时 ,对映选择性达到 5 9.2 % .
In the asymmetric hydrogenation of ethyl pyruvate catalyzed by Rh/PVP and Rh/PVP\|\{\%γ\%\|Al\-2O\-3\}, quinine as a chiral modifier can not only induce the enantioselectivity but also greatly accelerate the reaction rate.When nanocluster of Rh/PVP is supported on \%γ\%\|Al\-2O\-3, the catalytic activity and enantioselectivity increase obviously. Comparing the turnover frequency(TOF) and enantiomeric excess of \%R\%\|(+)\|ethyl lactate\%(e.e.\% value) of Rh/PVP with Rh/PVP\|\%γ\%\|Al\-2O\-3, the TOF and \%e.e\%. value rise by a factor of 10.6 and 2.03, respectively. The results indicate that \%γ\%\|Al\-2O\-3 plays a very important role in the asymmetric hydrogenation for the accelaration of the reaction and promoting the increase of enantioselectivity. It is possible that \%γ\%\|Al\-2O\-3 is fovourable for the dispersion of Rh/PVP on the support surface and inhibits the aggregation of Rh/PVP. Under the optimum conditions of 20 ℃, 7.0 MPa H\-2 and 3.86×10\+\{-3\} mol/L of quinine concentration in tetrahydrofuran, TOF and \%e.e.\% value using Rh/PVP\|\{\%γ\%\|Al\-2O\-3\} as catalyst can reach 871 h\+\{-1\} and 54.7%, respectively. When reaction temperature decreases to \{3 ℃, \} the \%e.e.\% value increases to 59.2%.
出处
《高等学校化学学报》
SCIE
EI
CAS
CSCD
北大核心
2002年第9期1758-1762,共5页
Chemical Journal of Chinese Universities
基金
香港理工大学 ASD项目资助
