WEKO3
アイテム
EDTAの化学構造表記にみられる混乱―分子か双性イオンか
http://hdl.handle.net/10069/00040793
http://hdl.handle.net/10069/00040793e5fb1da0-69a1-4217-9b04-1f7528033a0a
| 名前 / ファイル | ライセンス | アクション |
|---|---|---|
JTE_281_27.pdf (1.1 MB)
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| Item type | 学術雑誌論文 / Journal Article(1) | |||||
|---|---|---|---|---|---|---|
| 公開日 | 2021-06-18 | |||||
| タイトル | ||||||
| タイトル | EDTAの化学構造表記にみられる混乱―分子か双性イオンか | |||||
| 言語 | ||||||
| 言語 | jpn | |||||
| キーワード | ||||||
| 主題Scheme | Other | |||||
| 主題 | Acid-base titration | |||||
| キーワード | ||||||
| 主題Scheme | Other | |||||
| 主題 | Chemical structure | |||||
| キーワード | ||||||
| 主題Scheme | Other | |||||
| 主題 | Infrared spectroscopy | |||||
| キーワード | ||||||
| 主題Scheme | Other | |||||
| 主題 | X-ray analysis | |||||
| キーワード | ||||||
| 主題Scheme | Other | |||||
| 主題 | Zwitterion | |||||
| 資源タイプ | ||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_6501 | |||||
| 資源タイプ | journal article | |||||
| 著者 |
野口, 大介
× 野口, 大介 |
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| 著者別名 | ||||||
| 識別子Scheme | WEKO | |||||
| 識別子 | 118045 | |||||
| 姓名 | NOGUCHI, Daisuke | |||||
| その他のタイトル | ||||||
| その他のタイトル | Confusion in the Notation of the Chemical Structure of EDTA: Molecule or Zwitterion? | |||||
| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | Ethylenediaminetetraacetic acid (EDTA) is one of the well-known chelating ligands learned in analytical chemistry and widely used in such as industry and molecular biology to support our daily lives. It is also demonstrated as an acidic reagent in neutralization titration. The chemical structure indicates that EDTA is a tetrabasic acid; however, confusion of its notation exists in some textbooks. Some authors represent it as a neutral molecule, while others say it is a zwitterion. As the appropriate structure of EDTA seemed unclear, I surveyed some published research papers; herein I show in detail the historical controversy concerning the various proposed structures of EDTA, including non-ionized molecule and double zwitterion with ammonium carboxylate groups, both in solid state and aqueous solution. In the 1960s, some structures based on IR spectroscopic analyses were proposed; earlier studies exhibiting non-ionized EDTA molecular structure were almost overturned. Regrettably, without sufficient reference to each other, the idea of EDTA as a neutral molecule in a solid state still remained. After that, X-ray crystallographic studies confirmed the existence of EDTA as a double zwitterion also in a solid state, whereas an XPS investigation deduced that there are two kinds of nitrogen atoms, =N+H– and =N– types, in an EDTA molecule. Recent studies have revisited a double zwitterion form of EDTA in solution; however, some textbooks of analytical chemistry have shown the chemical structure of non-ionized EDTA, subsequently, as if “it returns to the beginning”. The reasons for this difficulty in interpreting the structure of EDTA in aqueous solution are considered to be as follow: (1) the poor solubility of EDTA itself in water made it quite difficult to be measured by IR spectroscopy in solution; (2) unexpected hydrogen bonds could change the frequencies of certain IR-active bonding; (3) there was some unawareness about its states, whether in solid or in solution; (4) the fact that EDTA has two different crystalline modifications with different IR spectra was almost unknown. I hope that the present study will be helpful in making the precise structure of EDTA in solution easily available based on literature for students, with a result that also would be of significance for those who teach and educate chemical analysis and technology. | |||||
| 書誌情報 |
技術･教育研究論文誌 en : Journal of Technology and Education 巻 28, 号 1, p. 27-36, 発行日 2021-06 |
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| 出版者 | ||||||
| 出版者 | 技術・教育研究会 | |||||
| 出版者別言語 | ||||||
| 値 | The Association of Technology and Education | |||||
| 権利 | ||||||
| 権利情報 | c2021 技術・教育研究会 | |||||
| 著者版フラグ | ||||||
| 出版タイプ | VoR | |||||
| 出版タイプResource | http://purl.org/coar/version/c_970fb48d4fbd8a85 | |||||
| 関係URI | ||||||
| 関連名称 | http://bigjohn.ce.fukui-nct.ac.jp/journal/index.htm | |||||
| 引用 | ||||||
| 内容記述タイプ | Other | |||||
| 内容記述 | 技術･教育研究論文誌, 28(1), pp.27-36; 2021 | |||||
