Liquid–Liquid Equilibrium for the Ternary System Water + 1-Methylimidazole + Ionic Liquid ([Hmim][PF₆], [Omim][PF₆], or [Omim][BF₄]) at 303.15 K

Abstract

To evaluate the feasibility of extraction of 1-methylimidazole from its low-concentration aqueous solution by ionic liquids, the liquid–liquid equilibrium of the ternary system of water + 1-methylimidazole + ionic liquid ([Hmim]­[PF6], [Omim]­[PF6], or [Omim]­[BF4]) was determined at 303.15 K and atmospheric pressure. The distribution coefficient and selectivity were calculated in accordance with the experimental results. The effects of the anion and cation of ionic liquids on the separation ability were discussed. The results indicated that the extraction capacity increased with increasing cationic carbon chain length, and the change of anions significantly affected the distribution coefficient and selectivity. As expected, the three ionic liquids were feasible as extractants for separating 1-methylimidazole from water. It also indicated that [Omim]­[PF6] was a more suitable extractant than [Hmim]­[PF6] and [Omim]­[BF4] for the extraction. The highest distribution coefficient and selectivity of [Omim]­[PF6] could reach 1.71 and 111.92, respectively, indicating [Omim]­[PF6] as a good choice for extracting 1-methylimidazole from water. In addition, the non-random two-liquid model was employed to successfully correlate the experimental data with a root-mean-square deviation of less than 0.0188. Moreover, a GUI-MATLAB tool was used to verify the consistency of the correlated parameters.

Probing the Effects of Size and Charge on the Monohydration and Dihydration of SiF5– and SiF62– via Comparisons with BF4– and PF6–

“…The silicon pentafluoride anion, SiF 5 – , is another relevant superhalogen, though less commonly studied ,,, relative to BF 4 – and PF 6 – . ,,,− These three anions have VDE values of or exceeding 9 eV, ,,, and their neutral parent molecules have EA values around 6 eV . The shared characteristics of BF 4 – , PF 6 – , and SiF 5 – provide an opportunity to probe the geometry dependence of microhydration patterns between the three singly charged anions.…”