Graduate School of Science and Engineering, Kagoshima University, 1-21-35, Korimoto, Kagoshima, 890-0065, Japan.
Graduate School of Science and Technology, Niigata University, 8050, Ikarashi 2-no-cho, Nishi-ku, Niigata, 950-2181, Japan.
Angew Chem Int Ed Engl. 2016 May 17;55(21):6266-9. doi: 10.1002/anie.201511328. Epub 2016 Apr 13.
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 H3 O(+) 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.
为了量化质子离子液体 (PILs) 作为酸碱反应介质的性质，在纯 PIL 硝酸乙基铵 (EAN) 中进行了电位滴定。在 EAN 和水中发现 12 种化合物的 14 个 pKa 值之间存在线性关系。换句话说，无论化合物的电荷和疏水性如何，EAN 中的 pKa 值都比水中的 pKa 值大约大一个单位。这可能是由于 EAN 中的 HNO3 比水中的 H3 O(+) 酸性更强，而不是由于离子的溶剂化状态不同。根据水中的 pH 值，EAN 的 pH 值范围在-1 到 9 之间。
