A pH Scale for the Protic Ionic Liquid Ethylammonium Nitrate |
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| Authors: | Prof. Ryo Kanzaki Prof. Hitoshi Kodamatani Prof. Takashi Tomiyasu Hikari Watanabe Prof. Yasuhiro Umebayashi |
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| Affiliation: | 1. Graduate School of Science and Engineering, Kagoshima University, Kagoshima, Japan;2. Graduate School of Science and Technology, Niigata University, Niigata, Japan |
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| Abstract: | To quantify the properties of protic ionic liquids (PILs) as acid–base reaction media, potentiometric titrations were carried out in a neat PIL, ethylammonium nitrate (EAN). A linear relationship was found between the 14 pKa values of 12 compounds in EAN and in water. In other words, the pKa value in EAN was found to be roughly one unit greater than that in water regardless of the charge and hydrophobicity of the compounds. It is possible that this could be explained by the stronger acidity of HNO3 in EAN than that of H3O+ in water and not by the difference in the solvation state of the ions. The pH value in EAN ranges from ?1 to 9 on the pH scale based on the pH value in water. |
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| Keywords: | acid– base catalysis acidity ionic liquids pH scale potentiometric titrations |
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