### Ion-Pair Extraction by Use of Liquid Crystals as Extracting SolventIon-Pair Extraction by Use of Liquid Crystals as Extracting Solvent

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 Author Ohki, Akira ♦ Takenaka, Shigeori ♦ Tsukada, Kadzuya ♦ Maeda, Shigeru ♦ Takagi, Makoto Source J-STAGE Content type Text Publisher The Japan Society for Analytical Chemistry Language English
 Subject Keyword Ion-pair extraction ♦ extracting solvent ♦ liquid crystal ♦ phase transition Abstract By using a liquid crystal, 4-cyano-4′-hexylbiphenyl (abbreviated as CHB), as an extracting solvent, the following ion-pair extraction reaction was investigated: $(QClO_{4})_{o}+(Pi^{-})_{w}_??_(QPi)_{o}+(ClO_{4}^{-})_{w}$ $(Q^{+}:$ cationic species such as Crystal Violet $(CV^{+}),$ Methylene Blue $(MB^{+})$ and tetrabutylammonium $(TBA^{+});$ $Pi^{-}:$ picrate anion; subscripts o and w denote organic and aqueous phases, respectively). The above extraction equilibrium was confirmed to hold in the case of a liquid crystal (CHB) solvent as well as in an ordinary solvent (hexylbenzene/cyanobenzene 1:1 mixture for comparison; abbreviated as MIX). The dependence of the extraction constant on the temperature was investigated. Only in the $CV^{+}-CHB$ system, the extraction constant discontinuously changed around a phase transition temperature of CHB (29°C; nematic/liquid). When an MIX solvent was used, such a phenomenon was not observed; the extraction constant gradually increased with an increase in temperature. The effect of the molecular orientation of the extracting solvent is discussed. ISSN 09106340 Learning Resource Type Article Publisher Date 1990-04-10 e-ISSN 13482246 Journal Analytical Sciences(analsci1985) Volume Number 6 Issue Number 2 Page Count 4 Starting Page 283 Ending Page 286