Solubility of alkali metal halides in the ionic liquid [C₄C₁im][OTf]

Abstract

The solubilities of the metal halides LiF, LiCl, LiBr, LiI, NaF, NaCl, NaBr, NaI, KF, KCl, KBr, KI, RbCl, CsCl, CsI, were measured at temperatures ranging from 298.15 to 378.15 K in the ionic liquid 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([C 4 . This study compares the influence of metal cation and halide anion on the solubility of salts within this ionic liquid. The highest solubility found was for iodide salts and the lowest solubility, for the three fluoride salts. There is no outstanding difference in the solubility of salts with matching anions in comparison to halide salts. The experimental data were correlated employing several phase equilibria models, including ideal mixtures, van't Hoff, the λh (Buchowski) equation, the modified Apelblat equation, and the non-random two-liquid model (NRTL). It was found that the van't Hoff model gave the best correlation results. On the basis of the experimental data the thermodynamic dissolution parameters (ΔH, ΔS, and ΔG) were determined for the studied systems together with computed gas phase metathesis parameters. Dissolution depends on the energy difference between enthalpies of fusion and dissolution of the solute salt. This demonstrates that overcoming the lattice energy of the solid matrix is the key to the solubility of inorganic salts in ionic liquids.

“Through‐Space” Relativistic Effects on NMR Chemical Shifts of Pyridinium Halide Ionic Liquids

“…Nevertheless, simple theoretical approaches based on static structures proved to be very successful . For example, Kuzmina and coworkers rationalized the solubility of alkali metal halides in [C 4 C 1 im][OTf] by considering ion clusters at DFT level . Chen and Izgorodina employed a cluster approach to predict the 1 H NMR properties of eight bulk [C 2 C 1 im] ILs without the necessity to explicitly include the dynamics of the system .…”

Chasing Aqueous Biphasic Systems from simple salts by exploring the LiTFSI/LiCl/H2O phase diagram

“…The predicted water content in the TFSI-rich phase is smaller than in the other, even though the ratio is slightly higher than the experimental one. The density profile for Cl − is also readily available from MD and indicates that its concentration in the 19 F, 7 Li, and 1 H obtained by NMR for the 12m LiCl−5m LiCl ABS compared with (B) those obtained by molecular dynamics simulations for Cl − , TFSI − , Li + , and H 2 O for the same system. On the top of panel B, a snapshot extracted from the simulation (Li + ions are colored orange, Cl − anions green, TFSI − anions red, and water molecules are not shown) illustrates the presence of a sharp interface.…”

Chasing Aqueous Biphasic Systems from Simple Salts by Exploring the LiTFSI/LiCl/H2O Phase Diagram

“…This claim is further supported by the low solubility of alkali halides in conventional ionic liquids. 19…”