Discrimination of Ca(II) and Mg(II) Ions Using 2-Acetyl-8-hydroxyquinoline-5-sulfonic Acids

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  • YAMAMOTO Yoshinori
    Department of Materials Science, Faculty of Engineering, Ibaraki University
  • KANAZAWA Hoko
    Department of Materials Science, Faculty of Engineering, Ibaraki University
  • KURITA Masaya
    Department of Materials Science, Faculty of Engineering, Ibaraki University
  • AOKI Shigeo
    Department of Materials Science, Faculty of Engineering, Ibaraki University
  • SEKIGUCHI Nobuo
    Department of Materials Science, Faculty of Engineering, Ibaraki University
  • BANDO Tsuyoshi
    Department of Materials Science, Faculty of Engineering, Ibaraki University

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Other Title
  • 2-アセチル-8-ヒドロキシキノリン-5-スルホン酸類によるCa (II) とMg (II) イオンの識別

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Description

Sodium 2-acetyl-8-hydroxyquinoline-5-sulfonate (1) and sodium 2, 4-diacetyl-8-hydroxyquinoline-5-sulfonate (2) were synthesized and characterized. The acid dissociation constant of 1 and 2, and the complex formation with Ca (II) and Mg (II) ions were determined from UV measurements in aq. solution at 25 °C: the pKa of the phenolic OH (ionic strength: 0.1) were 7.81 (1) and 7.45 (2), and pKa of the ring-N (Hammett's acidity function scale) were -0.31 (1) and -1.40 (2). The logarithm of formation constants of the metal complexes (the ratio 1: 1) (ionic strength: 0.1) was 3.87 (1-Ca), 1.48 (1-Mg), 3.60 (2-Ca), and 1.42 (2-Mg). The absorption maximum of the Ca complexes with 1 and 2 shifted to a longer wave-length, while there was no change in that of the Mg complexes. It is suggested that there is no chelating structure in the Mg complexes with 1 and 2 which act as weak monodentate ligands toward Mg in aq. solution.

Journal

  • NIPPON KAGAKU KAISHI

    NIPPON KAGAKU KAISHI 1998 (3), 181-186, 1998-03-10

    The Chemical Society of Japan

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