Mellein Berlyn R, Aki Sudhir N V K, Ladewski Rebecca L, Brennecke Joan F
Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556, USA.
J Phys Chem B. 2007 Jan 11;111(1):131-8. doi: 10.1021/jp0653353.
Room-temperature ionic liquids (ILs) have potential for many different applications, including catalysis and synthesis. Organics are often present during IL applications; therefore, a more fundamental understanding of the interactions between IL and organics is necessary. A systematic study of the effects of organic cosolvents, cations, and anions on the solvent strength of IL/organic mixtures will allow for a greater understanding and potential for tuning of ILs for specific purposes. Solvent strength is commonly quantified using spectroscopic probes. We report the solvent strength of IL/organic mixtures using Reichardt's dyes 30 and 33, Kamlet-Taft parameters, and phenol blue. The results show that the polarity of ILs is largely unaffected by the organic cosolvent; that is, the probes are preferentially solvated by the ILs. However, more specific solvation forces, such as hydrogen bonding, can be influenced indirectly by the strength of the anion/cation interaction, giving counterintuitive results.
室温离子液体(ILs)在许多不同应用中具有潜力,包括催化和合成。在离子液体应用过程中有机物质常常存在;因此,有必要更深入地了解离子液体与有机物质之间的相互作用。系统研究有机共溶剂、阳离子和阴离子对离子液体/有机混合物溶剂强度的影响,将有助于更深入地理解并有可能针对特定目的对离子液体进行调整。溶剂强度通常使用光谱探针进行量化。我们使用赖夏德特染料30和33、卡姆莱特-塔夫脱参数以及酚蓝来报告离子液体/有机混合物的溶剂强度。结果表明,离子液体的极性在很大程度上不受有机共溶剂的影响;也就是说,探针优先被离子液体溶剂化。然而,更具体的溶剂化作用力,如氢键,可能会受到阴离子/阳离子相互作用强度的间接影响,从而产生与直觉相反的结果。