School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, China.
Phys Chem Chem Phys. 2013 Nov 14;15(42):18694-701. doi: 10.1039/c3cp52146j.
The molecular structure and hydrogen bonding of ethylene glycol (EG) and EG-water mixtures in the liquid phase were studied by using near-infrared (NIR) spectroscopy. The spectra were evaluated using a two-dimensional (2D) correlation approach, moving-window 2D correlation analysis and chemometric methods. The minor changes for the CH stretching bands indicate that the structures of pure liquid EG and EG-water mixtures are determined by the intermolecular hydrogen bonding through the OH groups. The analysis of the ν2 + ν3 combination band of water reveals that in EG-rich solutions the molecules of water are predominantly bonded with two molecules of EG and this cooperative hydrogen bonding is stronger than that in bulk water. Further increase in the water content leads to formation of small water clusters around OH groups of EG. Comparing results for the binary mixtures of water with different organic solvents one can conclude that the total amount and distribution of the polar groups are the most important factors determining the solubility of water in the organic phase. The distribution of these groups depends on the length and structure of the hydrocarbon chain. Due to high population and relatively uniform distribution of the OH groups of EG water has unlimited solubility in liquid EG.
通过使用近红外（NIR）光谱法研究了乙二醇（EG）和 EG-水混合物在液相中的分子结构和氢键。使用二维（2D）相关方法、移动窗口 2D 相关分析和化学计量学方法评估了光谱。CH 伸缩带的微小变化表明，纯液体 EG 和 EG-水混合物的结构由通过 OH 基团的分子间氢键决定。对水的 ν2 + ν3 组合带的分析表明，在富 EG 的溶液中，水分子主要与两个 EG 分子键合，这种协同氢键比在本体水中更强。进一步增加水的含量会导致 EG 的 OH 基团周围形成小的水分子簇。比较水与不同有机溶剂的二元混合物的结果可以得出结论，极性基团的总量和分布是决定水在有机相中的溶解度的最重要因素。这些基团的分布取决于碳氢链的长度和结构。由于 EG 的 OH 基团的高丰度和相对均匀的分布，水在液体 EG 中有无限的溶解度。
