Spectroscopic determination of hydrogenation rates and intermediates during carbonyl hydrogenation catalyzed by Shvo's hydroxycyclopentadienyl diruthenium hydride agrees with kinetic modeling based on independently measured rates of elementary reactions
Spectroscopic determination of hydrogenation rates and intermediates during carbonyl hydrogenation catalyzed by Shvo's hydroxycyclopentadienyl diruthenium hydride agrees with kinetic modeling based on independently measured rates of elementary reactions
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DOI：
10.1021/ja077525c
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发表时间：
2008-02-20
影响因子：
15
通讯作者：
Johnson, Jeffrey B.
中科院分区：
文献类型：
--
作者：
Casey, Charles P.;Beetner, Sharon E.;Johnson, Jeffrey B.
用原位红外光谱法对甲苯和四氢呋喃中苯甲醛和苯乙酮的氢化反应进行了监测。观察到有机羰基化合物的消失和整个加氢反应中钌的浓度。测定了氢化速率与底物、H-2压力、总钌浓度和溶剂的关系。在甲苯中，桥接氢化二钌1是唯一可观察到的钌种类，直到几乎所有的底物都被消耗掉。在THF中，在加氢过程中观察到1和一些氢化一钌2。建立了基于催化各步骤速率常数的氢化反应动力学模型。这个动力学模型模拟了羰基化合物氢化的速率和氢化过程中钌1和2的含量。
The catalytic hydrogenation of benzaldehyde and acetophenone with the Shvo hydrogenation catalysts were monitored by in situ IR spectroscopy in both toluene and THF. The disappearance of organic carbonyl compound and the concentrations of the ruthenium species present throughout the hydrogenation reaction were observed. The dependence of the hydrogenation rate on substrate, H-2 pressure, total ruthenium concentration, and solvent were measured. In toluene, bridging diruthenium hydride 1 was the only observable ruthenium species until nearly all of the substrate was consumed. In THF, both 1 and some monoruthenium hydride 2 were observed during the course of the hydrogenation. A full kinetic model of the hydrogenation based on rate constants for individual steps in the catalysis was developed. This kinetic model simulates the rate of carbonyl compound hydrogenation and of the amounts of ruthenium species 1 and 2 present during hydrogenations.