Pandey Siddharth, Fletcher Kristin A, Baker Sheila N, Baker Gary A
Department of Chemistry, New Mexico Institute of Mining and Technology, Socorro, NM 87801, USA.
Analyst. 2004 Jul;129(7):569-73. doi: 10.1039/b402145m. Epub 2004 May 6.
Accurate data on transport properties such as viscosity are essential in plant and process design involving ionic liquids. In this study, we determined the absolute viscosity of the ionic liquid + water system at water mole fractions from 0 to 0.25 for three 1-alkyl-3-methylimidazolium ionic liquids: 1-butyl-3-methylimidazolium hexafluorophosphate, 1-butyl-3-methylimidazolium bis(trifluoromethane sulfonyl)imide and 1-ethyl-3-methylimidazolium bis(trifluoromethane sulfonyl)imide. In each case, the excimer to monomer ratio for 1,m-bis(1-pyrenyl)alkanes (m= 3 or 10) was found to increase linearly with the mole fraction of water. Of the probes studied only PRODAN and rhodamine 6G, both of which have the ability to participate in hydrogen bonding, exhibited Perrin hydrodynamic behavior in the lower viscosity bis(trifluoromethane sulfonyl)imides. As a result, these probes allow for the extrapolation of the absolute viscosity of the ionic liquid mixture from the experimental fluorescence steady-state polarization values.
在涉及离子液体的植物和工艺设计中，关于诸如粘度等传输性质的准确数据至关重要。在本研究中，我们测定了三种1-烷基-3-甲基咪唑鎓离子液体（1-丁基-3-甲基咪唑鎓六氟磷酸盐、1-丁基-3-甲基咪唑鎓双（三氟甲烷磺酰）亚胺和1-乙基-3-甲基咪唑鎓双（三氟甲烷磺酰）亚胺）在水摩尔分数为0至0.25的离子液体+水体系中的绝对粘度。在每种情况下，发现1,m-双（1-芘基）烷烃（m = 3或10）的准分子与单体比率随水的摩尔分数呈线性增加。在所研究的探针中，只有PRODAN和罗丹明6G这两种都具有参与氢键形成能力的探针，在较低粘度的双（三氟甲烷磺酰）亚胺中表现出佩林流体动力学行为。因此，这些探针能够根据实验荧光稳态极化值推断离子液体混合物的绝对粘度。
