- Effect of Hydroxyl Groups in a Cation Structure on the Properties of Ionic Liquids
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Two series of imidazolium ionic liquids with the bis(trifluoromethylsulfonyl)imide anion were synthesized, which differ by the presence of a hydroxyl group at the ω-position of the alkyl substituent in the cation structure (nC = 2–8). The properties of the liquids were studied by DSC, TGA, and IR and NMR spectroscopy. Their thermal stability was studied, and the melting points, viscosity, and volatility in vacuum were measured. The effect of OH groups in the structure of the ionic liquid on its properties was evaluated.
- Krasovskiy,Chernikova,Glukhov,Kapustin,Koroteev
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p. 2379 - 2385
(2019/01/03)
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- Experimental Densities and Calculated Fractional Free Volumes of Ionic Liquids with Tri- and Tetra-substituted Imidazolium Cations
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Although it has been estimated that there are at least 1 million ionic liquids (ILs) that are accessible using commercially available starting materials, a great portion of the ILs that have been experimentally synthesized, characterized, and studied in a variety of applications are built around the relatively simple 1-n-alkyl-3-methylimidazolium ([Cnmim]) cation motif. Yet, there is no fundamental limitation or reason as to why tri- or tetra-functionalized imidazolium cations have received far less attention. Scant physical property data exist for just a few trifunctionalized imidazolium-based ILs and there is virtually no data on tetra-functionalized ILs. Thus, there are a broad experimental spaces on the "map" of ILs that are largely unexplored. We have sought to make an initial expedition into these "uncharted waters" and have synthesized imidazolium-based ILs with one more functional group(s) at the C(2), C(4), and/or C(5) positions of the imidazolium ring (as well as N(1) and N(3)). This manuscript reports the synthesis and experimental densities of these tri- and tetra-functionalized ILs as well as calculated densities and fractional free volumes from COSMOTherm. To the best of our knowledge, this is the first report of any detailed experimental measurements or computational studies relating to ILs with substitutions at the C(4) and C(5) positions.
- Yue, Shuwen,Roveda, John D.,Mittenthal, Max S.,Shannon, Matthew S.,Bara, Jason E.
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p. 2522 - 2532
(2018/07/25)
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- Physicochemical properties of imidazolium-derived ionic liquids with different C-2 substitutions
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Five room temperature ionic liquids based on C-2 substituted imidazolium cations and bis(trifluoromethanesulfonyl)imide (TFSI) anions were synthesized and their physicochemical properties: thermal property, density, viscosity, ionic conductivity, self-diffusion coefficients, and electrochemical stability, were systematically investigated. The temperature dependence of both viscosity and ionic conductivities of these ionic liquids can be described by the Vogel-Fulcher-Tamman (VFT) equation. Compared with the reference, 1-propyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, the introduction of functional groups at the C-2 position generally increased the viscosity and lowered the ionic conductivity. The introduction of an ether group (-CH2OCH2CH2CH2CH3) at the C-2 position not only enhanced the reduction stability of the ionic liquids but also exhibited the lowest solid electrolyte interfacial resistance (R SEI). In contrast, the introduction of a cyano group (-CN) at the C-2 position not only decreased the reduction stability but also adversely increased the SEI resistance. The effect of the C-2 substitution on the reduction stability was explained by the change in the energy level of the lowest unoccupied molecular orbital. The self-diffusion coefficients (D) of each ion were measured by pulsed field gradient nuclear magnetic resonance (PFG-NMR). The lithium transference number (tLi) of 0.5 M LiTFSI/IL solutions calculated from the self-diffusion coefficients was in the range of 0.04 to 0.09.
- Liao, Chen,Shao, Nan,Han, Kee Sung,Sun, Xiao-Guang,Jiang, De-En,Hagaman, Edward W.,Dai, Sheng
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p. 21503 - 21510
(2012/03/10)
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- LCST-type liquid-liquid phase separation behaviour of poly(ethylene oxide) derivatives in an ionic liquid
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We present a new series of polymer-ionic liquid solutions exhibiting LCST-type liquid-liquid phase separation behaviour, and reveal their phase behaviour and intermolecular interactions based on phase diagrams and NMR analysis. The Royal Society of Chemistry.
- Tsuda, Ryohei,Kodama, Koichi,Ueki, Takeshi,Kokubo, Hisashi,Imabayashi, Shin-Ichiro,Watanabe, Masayoshi
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supporting information; experimental part
p. 4939 - 4941
(2009/06/06)
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