Effect of water concentration on the microstructures of choline chloride/urea (1:2) /water mixture

Effect of Water on Deep Eutectic Solvent/β-Cyclodextrin Systems

“…Recent NMR studies report for instance on the impact of water on the molecular interactions of reline and other pure DES and conclude that the deep eutectic solvent tends to become a simple solution of its individual counterparts upon dilution . On the other hand, molecular dynamics simulations as well as multiple experimental techniques indicate that even at high water mole fraction the components of reline are only partially hydrated, which means that the solution still retains the nature of pure DES. − In the mixture studied here, the description of intermolecular interactions is more complicated, since both water and β-cyclodextrin are available for hydrogen bonds, and the NMR results collected give some clues in this respect. With the addition of water choline gets more hydrated, as witnessed by the change in 1 H chemical shift and the decrease of τ c , but the T 1 and T 2 values are still shorter than those observed in aqueous solutions.…”

The peculiar effect of water on ionic liquids and deep eutectic solvents

“…Their results show that the addition of H 2 O breaks the strong H-bonds between the H atoms of urea and [Cl] À in the pure ChCl/urea (1 : 2) by preferentially hydrating [Cl] À and forming urea-water H-bonds. Gao et al 215 performed MD simulations to study the properties of ChCl/urea (1 : 2)-H 2 O mixtures from the pure ChCl/urea (1 : 2) to infinitely dilute ChCl/urea (1 : 2) solutions (x H 2 O = 0.999 or w H 2 O = 99.5%). The simulation results show that, even at x H 2 O = 0.9, neither [Cl] À nor cation is saturated by water, which means that, at this composition, the ions are only partially hydrated.…”

In Competition for Water: Hydrated Choline Chloride:Urea vs Choline Acetate:Urea Deep Eutectic Solvents

“…As DESs are hardly water-free, a primary goal is also to obtain an understanding of the effect of progressive addition of water on DES’s network. Indeed, although the presence of controlled amounts of water does not appear to disrupt the peculiar intermolecular connections, , the residual or intentionally added water has to be considered, as it will markedly affect the DES structure. Acting as an additional H-bond donor and acceptor, water participates in the intermolecular network and progressively weakens the intermolecular interactions between all ionic and neutral species until all DES components are fully solvated at high dilutions …”