Structural analysis of water in ionic liquid domains – A low pressure study

Influence of alkali metals on water dynamics inside imidazolium-based ionic liquid nano-domains

“…Surprisingly, at X w = 0.69, when the breakdown of the IL nanodomains is expected, no change in the diffusion coefficients' slope is notable, implying that the gradual dissolution of bulky EMIM + aggregates is disrupted by the systematically growing water-based aggregates. An analogous observation was previously reported for pure EMIM-DCA and water mixtures, where a transition region, representing the defragmentation of IL nano-domains was identified at 0.66 < X w ≤ 0.91 [Dziubinska-Kühn et al (2021)]. Thus, similarly to the observed 1 H NMR CS behaviour (Supplementary Figures S6-S11), the presence of a small amount of inorganic salt does not influence the principal EMIM-DCA and water interaction.…”

“…If IL and water are first mixed, H 2 O/D 2 O molecules will become incorporated into the IL polar domains and no longer be available to hydrate NaCl ions. As previously reported, even in the high vacuum (10 -5 mbar) conditions, single water molecules remain strongly hydrogen-bonded into the polar domains of EMIM-DCA [Dziubinska-Kühn et al (2021)]. Consequently, the number of free water molecules available to participate in the Na + hydration is lower and represents the sufficient IL:water:NaCl molecular ratio, enhancing the self-aggregation of water, clustering Na cations.…”

“…Although the advanced EMIM-DCA - water mutual relationship has been studied in detail ( Dziubinska-Kühn et al (2021) , the influence of NaCl on the water and IL molecules inside polar and non-polar EMIM-DCA nano-domains is not yet understood. Hence, extensive analysis, based on varying IL:water:NaCl molecular ratio, is performed using nuclear magnetic resonance (NMR) spectroscopy to gain information about the structure and diffusivity of sodium cation within different types of solvation shells formed by EMIM-DCA and/or water.…”

“…Importantly, the dispersion of the short tails has no longer random character, if the IL is doped with water. Recent studies revealed the presence of distinguished small water clusters, repetitively surrounded by polar and non-polar IL environment if n C = 2 [Saihara et al (2015); Dziubinska-Kühn et al (2021)], or n C = 4 [Gao and Wagner (2016)]. Moreover, the rigidness of the IL cation-anion arrangement leads to the induced distortion of small water aggregates, instead of their self-aggregation into larger structures [Kashin et al (2016); Ivanov et al (2021)].…”

Time‐Dependent Hydrogen Bond Network Formation in Glycerol‐Based Deep Eutectic Solvents

“…[41,42] A second approach introduces water as an external HBD added to type III DES, modifying their properties. [43] Similarly to ILs, [44] addition of water to glyceline can significantly reduce its density [45,46] and viscosity, [47] but also increase the electrical conductivity, [48] transport properties [49] or heat capacity, [50] due to the decreased molecular packing intensity resulting from more water-HBA/ HBD and less HBA-HBD interactions. [51] Consequently, addition of small water fractions to glyceline can facilitate its applications, e. g. biodiesel production, [52] induce the micellization of surfactants in DES [53] or improve the yield of a reaction in a medium.…”