Julien Maxime, Höhener Patrick, Robins Richard J, Parinet Julien, Remaud Gérald S
EBSI Team, CEISAM, University of Nantes-CNRS UMR 6230 , 2 rue de la Houssinière BP 92208, F-44322 Nantes, France.
Aix Marseille Univ, CNRS UMR 7376, Laboratoire Chimie Environnement, 3 place Victor Hugo, F-13331 Marseille, France.
J Phys Chem B. 2017 Jun 15;121(23):5810-5817. doi: 10.1021/acs.jpcb.7b00971. Epub 2017 May 31.
The relationship between the strength of the intermolecular interaction in liquid and the position-specific C fractionation observed during distillation was investigated. A range of molecules showing different intermolecular interactions in terms of mode and intensity were incorporated in the study. Although it had previously been suggested that during evaporation the diffusive C isotope effect in the thin liquid layer interfaced with vapor is not position-specific, herein we show that this is not the case. In particular, the position-specific effect was demonstrated for a series of alcohols. Our hypothesis is that intermolecular interactions in the liquid phase are the source of position-specific C fractionation observed on the molecule. A clear trend is observed between the C isotope effect of the carbon bearing the heteroatom of chemical function and the relative permittivity, the solvent hydrogen bond acidity, and the solvent hydrogen bond basicity, while only a weak trend was observed when using the C content of the whole molecule. Furthermore, two families of products appeared when using the hydrogen bond acidity parameter for the correlation by distinguishing H-acceptor and H-donor molecules from those H-acceptors only. This strongly reinforces the hypothesis of an important role of the C positioned close to the interaction center.
研究了液体中分子间相互作用强度与蒸馏过程中观察到的位置特异性碳分馏之间的关系。一系列在分子间相互作用的模式和强度方面表现出不同的分子被纳入该研究。尽管此前有人提出，在蒸发过程中，与蒸汽接触的薄液层中的扩散性碳同位素效应不是位置特异性的，但在此我们表明情况并非如此。特别是，对一系列醇类证明了位置特异性效应。我们的假设是，液相中的分子间相互作用是在分子上观察到的位置特异性碳分馏的来源。在带有化学官能团杂原子的碳的碳同位素效应与相对介电常数、溶剂氢键酸度和溶剂氢键碱度之间观察到明显的趋势，而在使用整个分子的碳含量时仅观察到微弱的趋势。此外，通过将氢受体和氢供体分子与仅那些氢受体区分开来，在使用氢键酸度参数进行相关性分析时出现了两类产物。这有力地强化了靠近相互作用中心的碳起重要作用的假设。
