The QUILL Research Centre, School of Chemistry and Chemical Engineering, Queen's University Belfast, Belfast BT9 5AG, UK.
Phys Chem Chem Phys. 2019 Oct 9;21(39):21782-21789. doi: 10.1039/c9cp04343h.
The structure of choline chloride/glycerol (ChCl : Gly) mixtures at two mole fractions (the eutectic χChCl = 0.33 (1 : 2), and a higher χChCl = 0.50 (1 : 1) composition) in the liquid state at 333 K and 1 atm. has been investigated using neutron diffraction coupled with hydrogen/deuterium isotopic substitution. Modelling using the empirical potential structure refinement (EPSR) technique, constrained to the experimental neutron diffraction data, produced structural models at both compositions consistent with the experimental data with an extensive, persistent homo-molecular glycerol hydrogen bonding network at χChCl = 0.33 similar to that present in pure glycerol and suggests that persistence of the latent glycerol hydrogen bonding network is key to formation of the ChCl : Gly deep eutectic solvent. In the choline chloride-rich χChCl = 0.50 composition, significant domain segregation is observed with a dramatic reduction in the extent of the homo-molecular glycerol hydrogen bond network which is replaced by a more homogeneous system-wide hydrogen bonded network incorporating glycerol, Cl-, and choline cations.
在 333 K 和 1 个大气压下，研究了在液态下两种摩尔分数（共晶 χChCl = 0.33（1：2）和更高的 χChCl = 0.50（1：1）组成）的氯化胆碱/甘油（ChCl：Gly）混合物的结构。使用中子衍射结合氢/氘同位素取代，结合经验势能结构精修（EPSR）技术对模型进行建模，该模型限制在实验中子衍射数据内，在两个组成部分都生成了与实验数据一致的结构模型，在 χChCl = 0.33 处存在广泛且持久的同分子甘油氢键网络，类似于纯甘油中的情况，这表明潜伏的甘油氢键网络的持续存在是形成 ChCl：Gly 深共晶溶剂的关键。在氯化胆碱丰富的 χChCl = 0.50 组成中，观察到明显的域分离，同分子甘油氢键网络的程度急剧降低，取而代之的是更均匀的全系统氢键网络，其中包括甘油、Cl-和胆碱阳离子。
