A kinetic probe of the effect of a stabilizing polymer on a colloidal catalyst: Accelerated enantioselective hydrogenation of ethyl pyruvate catalyzed by poly(vinylpyrrolidone)-stabilized platinum colloids

被引:47
作者
Kohler, JU [1 ]
Bradley, JS [1 ]
机构
[1] Max Planck Inst Kohlenforsch, D-45470 Mulheim, Germany
关键词
D O I
10.1021/la971178a
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
The enantioselective hydrogenation of ethyl pyruvate to (R)-ethyl lactate has been used as a reaction probe of the surface environment of colloidal platinum stabilized in ethanol with poly(vinylpyrrolidone). The rates of hydrogenation and the rates at which the acceleration is induced upon addition of the modifier (cinchonidine) have been compared for the colloidal catalyst and a 1% Pt/Al2O3 catalyst of equal platinum particle size under identical conditions. The results show that the presence of the stabilizing polymer in the colloidal catalyst does not hinder access of the modifier molecule to the colloidal metal surface but that the polymer may, by adsorption at the metal surface, reduce the number of surface-modified sites available for the faster enantioselective hydrogenation.
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页码:2730 / 2735
页数:6
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