Centre for Sustainable Chemical Technologies, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
ISIS Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell, Oxford, OX11 0QX, UK.
Angew Chem Int Ed Engl. 2017 Aug 7;56(33):9782-9785. doi: 10.1002/anie.201702486. Epub 2017 May 29.
The nanostructure of a series of choline chloride/urea/water deep eutectic solvent mixtures was characterized across a wide hydration range by neutron total scattering and empirical potential structure refinement (EPSR). As the structure is significantly altered, even at low hydration levels, reporting the DES water content is important. However, the DES nanostructure is retained to a remarkably high level of water (ca. 42 wt % H O) because of solvophobic sequestration of water into nanostructured domains around cholinium cations. At 51 wt %/83 mol % H O, this segregation becomes unfavorable, and the DES structure is disrupted; instead, water-water and DES-water interactions dominate. At and above this hydration level, the DES-water mixture is best described as an aqueous solution of DES components.
通过中子总散射和经验势结构精修（EPSR），研究了一系列氯化胆碱/尿素/水深共晶溶剂混合物在宽水合范围内的纳米结构。由于结构发生了显著变化，即使在低水合水平下，报告 DES 的含水量也很重要。然而，由于水被疏水隔离在胆碱阳离子周围的纳米结构域内，因此 DES 的纳米结构可以保留到非常高的含水量（约 42wt%H2O）。在 51wt%/83mol%H2O 时，这种分离变得不利，DES 结构被破坏；相反，水-水和 DES-水相互作用占主导地位。在这个水合水平及以上，DES-水混合物最好被描述为 DES 组分的水溶液。
