Study on the hydrophobicity of [Bmim]2[CuCl4] by two-dimensional correlation spectroscopy

By dissolving copper chloride in [Bmim]Cl (1-butyl-3-methylimidazolium chloride), chloride ions can coordinate with copper ions and form [CuCl4]2−, thereby inducing the solution being hydrophobic. In the present work, hydrogen bonds between [Bmim]+ and anions are analyzed and discussed by two-dimensional correlation spectroscopy. Time-dependent attenuated total reflection spectroscopy (ATR-FTIR) is introduced to monitor the hygroscopic process of [Bmim]2[CuCl4] and [Bmim]Cl in situ. Hygroscopic capacity and rate of [Bmim]2[CuCl4] shrink compared with [Bmim]Cl. The change of water molecular clusters has been studied by second-derivative spectra in the hygroscopic process. The behaviors of water molecular in the two ionic liquids are also distinctive.