Physicochemical and Acid-base Properties of a Series of 2-Hydroxyethylammonium-based Protic Ionic Liquids

• SONG Xuedan

  Department of Chemistry, Faculty of Sciences, Kyushu University

• KANZAKI Ryo

  Department of Earth and Environmental Sciences, Graduate School of Science and Engineering, Kagoshima University

• ISHIGURO Shin-ichi

  Department of Chemistry, Faculty of Sciences, Kyushu University

• UMEBAYASHI Yasuhiro

  Department of Chemistry, Faculty of Sciences, Kyushu University

Abstract

Physicochemical properties such as a thermal behavior, ionic conductivity, viscosity and density, and acid-base properties of a new class of 2-hydroxyethylammonium-based protic ionic liquids (PILs) have been investigated. Thirty-six potential PILs were surveyed to find 32 salts with a melting point below 373 K. Among them, [(EtOH)_nEt_(3−n)NH⁺][TFS⁻] (Et, C₂H₅; n = 0 – 3) and [(EtOH)₂EtNH⁺][X⁻] (X = TFS, trifluoromethanesulfonate; TFSA, bis(trifluoromethanesulfonyl)amide; NO₃) were studied in terms of the Walden plots, molar volume and auto-protolysis reaction for effect of the number of 2-hydroxyethyl groups introduced in the cations and for dependence of the anion nature, respectively. With regard to [(EtOH)_nEt_(3−n)NH⁺][TFS⁻] (n = 0 – 3), the ion-ion interactions between cation-anion and cation-cation were enhanced with increasing the number of the 2-hydroxyethyl groups. In addition, the auto-protolysis constant K_s value for [(EtOH)₂EtNH⁺][TFSA⁻] is smaller than that for TFS⁻ based PIL, indicating that HTFSA behaves as a stronger acid than HTFS in the respective PIL. On the other hand, in [(EtOH)₂EtNH⁺][NO₃⁻], the emf jump was rather small, which suggests that the proton of HNO₃ does not easily transfer to (EtOH)₂EtN in the liquid state.

Journal

• Analytical Sciences

  Analytical Sciences 28 (5), 469-474, 2012

  The Japan Society for Analytical Chemistry

Keywords

• Analytical Chemistry

Details

• CRID: 1390001204262054912
• NII Article ID: 10030757409
• NII Book ID: AA10500785
• DOI: 10.2116/analsci.28.469
• COI: 1:STN:280:DC%2BC38jgslyksg%3D%3D
• ISSN: 13482246
• ISSN: 09106340
• NDL BIB ID: 023613975
• PubMed: 22687926
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I023613975
• Web Site: https://link.springer.com/content/pdf/10.2116/analsci.28.469.pdf
• Web Site: https://link.springer.com/article/10.2116/analsci.28.469/fulltext.html
• Web Site: https://www.jstage.jst.go.jp/article/analsci/28/5/28_469/_pdf
• Text Lang: en
• Data Source:
  • JaLC
  • NDL
  • Crossref
  • PubMed
  • CiNii Articles
  • KAKEN
• Abstract License Flag: Disallowed