open access

https://hdl.handle.net/2115/91261

Estimation of a eutectic composition of imidazolium chloride ionic liquids using video imaging and impedance methods

英語

Impedance

2022-07

Elsevier

Fluid phase equilibria

558

113442

The eutectic temperature T-e and composition X-e of binary systems composed of three ionic liquids, 1-ethyl-3-methylimidazolium chloride ([C(2)MiM] Cl), 1-methyl-3-propylimidazolium chloride ([C(3)MiM]Cl), and 1-butyl-3-methylimidazolium chloride ([C(4)mim]Cl), were estimated using a video imaging method, in which the formation of a liquid phase on solidified ionic liquids at a given composition stored in a vial was detected from time-lapse images taken during temperature scanning. The advantage of this method is that multiple samples (five samples in this study) could be measured simultaneously, whereas its disadvantage is a less accurate determination of the melting point compared with the conventional differential scanning calorimetry (DSC) method. The T-e and X-e of [C(2)min]CHC(3)mim]Cl, [C(2)min]CHC(4)mim]Cl, and [C(3)mim]Cl-[C(4)mim]Cl binary systems were roughly estimated. Furthermore, the T e of the ternary system of the [C(2)mim]Cl-[C(3)mim]Cl-[C(4)mim]Cl with limited compositions was estimated, which was lower than that of the binary systems. The transition of the electrochemical impedance of [C(2)mim]Cl ionic liquids was also measured using two Pt wire electrodes as a function of temperature. The differential inversed resistance curve (dR(-1)/dT)-T shows an obvious peak corresponding to the phase transition from a low conductive solid phase to a highly conductive liquid phase. This peak was comparable with the peak obtained in the DSC measurement. (C) 2022 Elsevier B.V. All rights reserved.

学術雑誌論文

Accepted Manuscript

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©2022. This manuscript version is made available under the CC-BY-NC-ND 4.0 license https://creativecommons.org/licenses/by-nc-nd/4.0/

0378-3812