Maximise Equilibrium Conversion in Biphasic Catalysed Reactions: How to Obtain Reliable Data for Equilibrium Constants?
Maximise Equilibrium Conversion in Biphasic Catalysed Reactions: How to Obtain Reliable Data for Equilibrium Constants?
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最大化双相催化反应中的平衡转化：如何获得平衡常数的可靠数据？
DOI：
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
U. Kragl
中科院分区：
文献类型：
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作者：
Marrit Eckstein;J. Lembrecht;J. Schumacher;W. Eberhard;A. Spiess;M. Peters;Christoph Roosen;L. Greiner;W. Leitner;U. Kragl
为了预测和优化双相催化反应中的平衡转化率，必须知道所需反应的平衡常数和所有反应物的分配系数。在这篇文章中，我们研究了双相反应介质中醇脱氢酶催化的几种直链和芳香酮的还原与平衡转化的关系。在该示例中，平衡常数可以用氧化还原电位差ΔE0来表示。然而，对于多种有机化合物，这些数据在文献中相当罕见。为了克服数据缺乏的问题，我们利用计算化学方法来计算吉布斯自由能 ΔGR 的数据，从而得出一系列同系线性酮的平衡常数。为了获得取代苯乙酮衍生物还原的可比数据，哈米特关系得出必要的平衡常数。此外，我们还比较了醇脱氢酶催化还原反应的一组辅因子再生方法的平衡转化率。这些结果导致了一种节省时间的实验设计，可利用双相反应条件以制备规模将 2-辛酮对映选择性还原为 (R)-2-辛醇。
For the prediction and optimisation of the equilibrium conversion in biphasic catalysed reactions, the equilibrium constant of the desired reaction and the partition coefficients of all reactants have to be known. Within this contribution we have examined the alcohol dehydrogenase-catalysed reduction of several linear and aromatic ketones in biphasic reaction media with respect to equilibrium conversion. In this example, the equilibrium constant can be expressed in terms of differences in oxidation-reduction potentials ΔE0. However, for a large variety of organic compounds, these data are quite rare in the literature. To overcome this lack of data, we have utilised methods of computational chemistry to calculate data for the Gibbs free energy ΔGR leading to the equilibrium constants of a homologous series of linear ketones. To obtain comparable data for the reduction of substituted acetophenone derivatives, the Hammett relation leads to the necessary equilibrium constants. Furthermore, we compare the equilibrium conversions of a set of cofactor regeneration methods for the alcohol dehydrogenase-catalysed reductions. These results lead to a time-saving experimental design for the enantioselective reduction of 2-octanone to (R)-2-octanol on a preparative scale utilising biphasic reaction conditions.