Connecting Structural and Transport Properties of Ionic Liquids with Cationic Oligoether Chains
Connecting Structural and Transport Properties of Ionic Liquids with Cationic Oligoether Chains
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DOI：
10.1149/2.0371708jes
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发表时间：
2017-01-01
影响因子：
3.9
通讯作者：
Wishart, James F.
中科院分区：
文献类型：
--
作者：
Lall-Ramnarine, Sharon I.;Zhao, Man;Wishart, James F.
采用X射线衍射和分子动力学模拟方法研究了两类阳离子上含低聚醚尾的离子液体的结构。制备了具有长度范围为4至10个原子的侧链的咪唑钥和吡咯烷钥双（三氟甲基磺酰基）酰胺IL，包括直链烷基和低聚环氧乙烷尾。测量了它们的物理性质，如粘度、电导率和热分布，并比较了系统趋势。与早期文献一致，与其烷基同系物相比，单个醚取代基显著降低了吡咯烷钥和咪唑钥离子液体的粘度。值得注意的是，随着吡咯烷钥离子液体中醚单元数目的增加，粘度几乎没有任何增加，与烷基吡咯烷钥离子液体相反，烷基吡咯烷钥离子液体的粘度随着链长稳定增加。咪唑钥醚离子液体的粘度随链长增加而增加，但始终保持远低于其烷基同系物。为了补充实验确定的属性，分子动力学模拟上运行的两个离子液体与最长的醚链。研究结果指出，可能是有用的研究人员设计的IL的特定应用程序的具体方面。(C)作者（S）2017由ECS发布。All rights reserved.
X-ray diffraction and molecular dynamics simulations were used to probe the structures of two families of ionic liquids containing oligoether tails on the cations. Imidazolium and pyrrolidinium bis(trifluoromethylsulfonyl)amide ILs with side chains ranging from 4 to 10 atoms in length, including both linear alkyl and oligo-ethylene oxide tails, were prepared. Their physical properties, such as viscosity, conductivity and thermal profile, were measured and compared for systematic trends. Consistent with earlier literature, a single ether substituent substantially decreases the viscosity of pyrrolidinium and imidazolium ILs compared to their alkyl congeners. Remarkably, as the number of ether units in the pyrrolidinium ILs increases there is hardly any increase in the viscosity, in contrast to alkylpyrrolidinium ILs where the viscosity increases steadily with chain length. Viscosities of imidazolium ether ILs increase with chain length but always remain well below their alkyl congeners. To complement the experimentally determined properties, molecular dynamics simulations were run on the two ILs with the longest ether chains. The results point to specific aspects that could be useful for researchers designing ILs for specific applications. (C) The Author(s) 2017. Published by ECS. All rights reserved.