Zwitterion/Brønsted Acid Mixtures Showing Controlled Lower Critical Solution Temperature-Type Phase Changes with Water.
A new ammonium-type zwitterion (ZI), N,N-dihexyl-N-monopentyl-3-sulfonyl-1-propaneammonium (N665 C3S) with adequate hydrophobicity showed reversible and highly temperature-sensitive lower critical solution temperature (LCST)-type phase transitions after being mixed with pure water. Generally for such compounds, those with longer alkyl chains were immiscible with water and those with shorter chains were miscible with water, regardless of temperature. A slightly more hydrophobic ZI than N665 C3S showed LCST-type phase behavior with water when it was mixed with equimolar amounts of a Brønsted acid such as trifluoromethanesulfonic acid (HTfO). The phase-transition temperature of the ZI/Brønsted acid mixed aqueous solution was controllable by water content.
Department of Biotechnology, Tokyo University of Agriculture and Technology, 2-24-16, Naka-cho, Koganei, Tokyo, 184-8588, Japan.|Functional Ionic Liquid Laboratories, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16, Naka-cho, Koganei, Tokyo, 184-8588, Japan.
Yuki
Y
Mieno
Department of Biotechnology, Tokyo University of Agriculture and Technology, 2-24-16, Naka-cho, Koganei, Tokyo, 184-8588, Japan.|Functional Ionic Liquid Laboratories, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16, Naka-cho, Koganei, Tokyo, 184-8588, Japan.
Yuki
Y
Kohno
Department of Biotechnology, Tokyo University of Agriculture and Technology, 2-24-16, Naka-cho, Koganei, Tokyo, 184-8588, Japan.|Functional Ionic Liquid Laboratories, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16, Naka-cho, Koganei, Tokyo, 184-8588, Japan.
Shohei
S
Saita
Department of Biotechnology, Tokyo University of Agriculture and Technology, 2-24-16, Naka-cho, Koganei, Tokyo, 184-8588, Japan. ohnoh@cc.tuat.ac.jp, ohnoh@cc.tuat.ac.jp.|Functional Ionic Liquid Laboratories, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16, Naka-cho, Koganei, Tokyo, 184-8588, Japan. ohnoh@cc.tuat.ac.jp, ohnoh@cc.tuat.ac.jp.
Hiroyuki
H
Ohno
Brønsted acids; ionic liquids; lower critical solution temperature; phase transitions; zwitterions