Structural Heterogeneities in Solutions of Triethylamine Nitrate Ionic Liquid: H-1 NMR and LC Model Study
Structural Heterogeneities in Solutions of Triethylamine Nitrate Ionic Liquid: H-1 NMR and LC Model Study
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三乙胺硝酸盐离子液体溶液中的结构异质性：H-1 NMR 和 LC 模型研究
DOI：
10.1007/s10953-016-0449-y
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发表时间：
2016
影响因子：
1.2
通讯作者：
Yingjie Xu
中科院分区：
文献类型：
--
作者：
Xiao Zhu;Huan Zhang;Yingjie Xu
为了揭示铵基离子液体溶液中的微观结构异质性，采用酸碱中和合成了硝酸三乙胺（N222NO3），并在298.15 K下测量了不同浓度的两种二元混合物（即N222NO3/二甲基亚砜（DMSO）和N222NO3/丙酮）的1H NMR谱。采用内参法获得了浓度依赖性化学物质。 N222NO3 中 –CH3 的位移，已使用 1 H NMR 局部组成 (LC) 模型进行关联以获得局部摩尔分数。研究表明，在富含 N222NO3 的区域内，离子液体的自缔合占主导地位，而不是 N222NO3 与溶剂的相互作用。然而，在富溶剂区域，N222NO3主要与溶剂分子相互作用，表明N222NO3的自缔合网络已被溶剂极大破坏。此外，还检测到了 DMSO 和丙酮的不同影响。由于其较高的介电常数，DMSO分子更有效地破坏离子液体的原始网络。此外，N222NO3/DMSO 体系中的LC 行为比N222NO3/丙酮中更显着，表明DMSO 可以在DMSO/N222NO3 混合物中诱导更明显的异质性，这与溶液的物理化学性质和纤维素溶解度一致。
In order to uncover the micro-structural heterogeneities in solutions of ammonium based ionic liquids, triethylamine nitrate (N222NO3) has been synthesized using acid–base neutralization and the1H NMR spectra of two binary mixtures, namely N222NO3/dimethyl sulfoxide (DMSO) and N222NO3/acetone at different concentrations, have been measured at 298.15 K. The internal reference method was adopted to obtain the concentration-dependent chemical shifts of –CH3in N222NO3, which have been correlated using the1H NMR local composition (LC) model to obtain the local mole fractions. It has been revealed that within N222NO3rich region, self-association of the ionic liquid was predominant instead of N222NO3–solvent interactions. However, in the solvent rich region, N222NO3mainly interacts with solvent molecules, indicating that the self-association network of N222NO3has been greatly destroyed by solvents. In addition, the different influences of DMSO and acetone have been detected. DMSO molecules more effectively destroy the original network of the ionic liquid, due to its higher dielectric constant. Also, LC behavior in N222NO3/DMSO systems is more significant than in N222NO3/acetone, indicating that DMSO can induce more obvious heterogeneities in DMSO/N222NO3mixtures, which is consistent with physicochemical properties and cellulose solubility of solutions.