Extrathermodynamic relationships in reversed-phase liquid chromatography.
Extrathermodynamic relationships in reversed-phase liquid chromatography.
复制标题
反相液相色谱中的外热力学关系。
DOI：
10.1021/ac020245p
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发表时间：
2002
影响因子：
7.4
通讯作者：
G. Guiochon
中科院分区：
文献类型：
--
作者：
Kanji Miyabet;G. Guiochon
焓-熵补偿（EEC）和线性自由能关系（LFER）是经常用于讨论化学平衡和反应动力学的机理相似性的超热力学关联。虽然是经验性的，但它们被广泛应用，证明了基于它们的基础研究的实质性有效性。对EEC和LFER的必要条件（或前提条件）进行了许多理论解释。众所周知，LFER依赖于EEC的存在。然而，从分子结构贡献的角度，EEC与LFER之间的密切关系以及LFER的温度依赖性还没有得到充分的讨论。我们提出了一个简单的LFER模型的斜率和截距LFER的补偿温度，本身来自EEC分析，和几个参数表征分子贡献的焓和熵的变化与通道从一个阶段的色谱系统的其他。对EEC和LFER这两类超热力学关系式之间的密切关系提供了理论解释。我们还证明了EEC和LFER的特性取决于结构参数。这个新的模型允许一个适当的解释LFER的温度依赖性。它应该允许进一步的基础研究的化学反应机理的基础上的超热力学关系。
Enthalpy-entropy compensation (EEC) and linear free energy relationships (LFER) are extrathermodynamic correlations frequently used to discuss the mechanistic similarities of chemical equilibria and reaction kinetics. Although empirical, they are widely applied, proving the substantial effectiveness of fundamental studies based on them. Many attempts have been made to interpret theoretically the necessary conditions (or preconditions) of EEC and LFER. LFER is known to rest on the existence of EEC. However, the intimate correlations between EEC on one hand and LFER and the temperature dependence of LFER on the other hand were insufficiently discussed from the viewpoint of molecular structure contributions. We present a simple LFER model relating the slope and intercept of LFER to the compensation temperatures, themselves derived from EEC analyses, and to several parameters characterizing the molecular contributions to the changes in enthalpy and entropy associated with the passage from one phase of the chromatographic system to the other. A theoretical explanation is supplied for the intimate correlation between the two types of extrathermodynamic relationships, EEC and LFER. We demonstrate also that the characteristics of EEC and LFER depend on the structural parameters. This new model allows a proper interpretation of the temperature dependence of LFER. It should permit further progress of fundamental studies of chemical reaction mechanisms based on extrathermodynamic relationships.