甘氨酸离子液体[C3mim][Gly]和[C4mim][Gly]水溶液的表面张力

The surface tension of aqueous glycine ionic liquids: [C_3mim][Gly] and [C_4mim][Gly]

本文用中和法合成了基于烷基咪唑的甘氨酸离子液体[C3mim][Gly](1-丙基-3-甲基咪唑甘氨酸离子液体)和[C4mim][Gly](1-丁基-3-甲基咪唑甘氨酸离子液体),在298.15K下,0.0400～0.5000molkg-1浓度范围内测定了不同浓度[C4mim][Gly]和[C3mim][Gly]离子液体水溶液的密度和表面张力,得到了溶液等张比容的实验值,提出了预测不同浓度溶液等张比容的经验方程,利用这个经验方程和李以圭等人提出的溶液表面张力模型,分别估算了这两种离子液体水溶液的表面张力,其估算值和实验值在误差范围内很好地吻合.

The amino acid ionic liquids （AAILs） [C3mim][Gly] （1-propyl-3-methylimidazolium glycine） and [C4mim][Gly] （1-butyl-3-methylimidazolium glycine） were prepared by the neutralization method and characterized by 1H NMR spectroscopy and differential scanning calorimetry （DSC）. The values of their density, surface tension and refractive index were measured at （298.15± 0.05） K. Since the AAILs can form strong hydrogen bonds with water, small amounts of water are difficult to remove from the AAILs by common methods. In order to eliminate the effect of the impurity water, the standard addition method （SAM） was applied to these measurements. A new concept which is called the ionic parachor has been put forward. The [C,mim]＋ cations were treated as a group of reference ions and the individual values of their ionic parachor were evaluated in terms of an extrathermodynamic assumption. Then, using the values of the ionic parachor of reference ions, the parachor, surface tension y and refractive index nD of the ionie liquids investigated in this work were estimated. The estimated values correlate quite well with the corresponding experimental values.