174899-90-2Relevant academic research and scientific papers
Study on thermodynamic properties and estimation of polarity of ionic liquids {[Cnmmim][NTf2] (n = 2, 4)}
Wei, Jie,Ma, Tianyou,Ma, Xiaoxue,Guan, Wei,Liu, Qingshan,Yang, Jiazhen
, p. 30725 - 30732 (2014)
Two bis(trifluoromethyl sulfonyl)imide ionic liquids [Cnmmim] [NTf2] (n = 2, 4) {1-alkyl-2,3-dimethyimidazolium-N,N- bis(trifluoromethyl sulfonyl)imide} were prepared and characterized by 1H NMR spectroscopy and differential scanning calorimetry (DSC). The values of their density, surface tension and refractive index were measured in the temperature range of (298.15 to 338.15 ± 0.01) K and the average contributions to the density, surface tension, and refractive index per methyl group in the alkyl chain and the addition of a methylene group in the imidazolium ring for the ILs were discussed. The dependence of volumetric properties, surface properties and molar refraction on temperature was discussed. Based on Kabo's method and Verevkin's experimental values, the molar enthalpies of vaporization, ΔHv, for [Cnmmim] [NTf2] (n = 2, 4) were estimated. As a new idea, it was put forward that ΔHv can be assumed to consist of two parts: a part corresponds with the induced energy, ΔHvn, and another part corresponds with orientation energy from the permanent dipole moment of the ion pair in ILs, ΔHvμ. The values of ΔHvn were calculated in terms of the Lawson-Ingham equation so that the values of ΔHvμ could be estimated. Using the values of ΔHv, ΔH vn and ΔHvμ, cohesive energy density, δ2 (δ is Hildebrand solubility parameter), the contribution of induced energy, δn2, and the contribution of orientation energy, δμ2, were obtained. If a liquid only has δn then it is a non-polar liquid and if a liquid not only has δn, but also has δμ then it is a polar liquid. Since the ion pairs in ILs have a permanent dipole moment, the ionic liquid has a certain polarity. Therefore, using δμ as the polarity scaling of ILs is very convenient because the values of δμ are very easy to calculate from the enthalpy of vaporization and refractive index data.
Halogen bonding effect on electrochemical anion oxidation in ionic liquids
Alvarez, Marie Stacey,Houzé, Cedric,Groni, Sihem,Sch?llhorn, Bernd,Fave, Claire
supporting information, p. 7587 - 7593 (2021/09/22)
Three Ionic liquids (ILs) based on an imidazolium core have been compared and used as solvents for the oxidation of various anions. Electrochemical experiments as well as NMR titrations and X-ray diffraction analyses unambiguously confirm the crucial role of non-covalent halogen bonding on the oxidation potentials and consequently the electrochemical window of the respective ILs.
Experimental Densities and Calculated Fractional Free Volumes of Ionic Liquids with Tri- and Tetra-substituted Imidazolium Cations
Yue, Shuwen,Roveda, John D.,Mittenthal, Max S.,Shannon, Matthew S.,Bara, Jason E.
, p. 2522 - 2532 (2018/07/25)
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.
Effect of Hydroxyl Groups in a Cation Structure on the Properties of Ionic Liquids
Krasovskiy,Chernikova,Glukhov,Kapustin,Koroteev
, p. 2379 - 2385 (2019/01/03)
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.
N-Heterocyclic Olefin–Carbon Dioxide and –Sulfur Dioxide Adducts: Structures and Interesting Reactivity Patterns
Finger, Lars H.,Guschlbauer, Jannick,Harms, Klaus,Sundermeyer, J?rg
, p. 16292 - 16303 (2016/10/30)
Depending on the amount of methanol present in solution, CO2adducts of N-heterocyclic carbenes (NHCs) and N-heterocyclic olefins (NHOs) have been found to be in fully reversible equilibrium with the corresponding methyl carbonate salts [EMIm][O
Sonochemical synthesis of 0D, 1D, and 2D zinc oxide nanostructures in ionic liquids and their photocatalytic activity
Alammar, Tarek,Mudring, Anja-Verena
experimental part, p. 1796 - 1804 (2012/04/04)
Ultrasound synthesis of zinc oxide from zinc acetate and sodium hydroxide in ionic liquids (ILs) is a fast, facile, and effective, yet highly morphology- and size-selective route to zinc oxide nanostructures of various dimensionalities. No additional organic solvents, water, surfactants, or templating agents are required. Depending on the synthetic conditions, the selective manufacturing of 0D, 1D, and 2D ZnO nanostructures is possible: Whereas the formation of rodlike structures is typically favored, ZnO nanoparticles can be obtained either under strongly basic conditions or by use of ILs with a long alkyl chain, such as 1-n-alkyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([Cnmim][Tf2N]; n>8). A short ultrasound irradiation time favors the formation of ZnO nanosheets. Prolonged irradiation leads to the conversion of the ZnO nanosheets into nanorods. In contrast, ionothermal synthesis (conventional heating) does not allow for morphology tuning by variation of the IL or other synthesis conditions, as the longer reaction times required lead always to the formation of well-developed hexagonal nanocrystals with prismatic tips. The ZnO nanostructures synthesized by using ultrasound were efficient photocatalysts in the photodegradation of methyl orange. The photoactivity was observed to be as high as 95 % for ZnO nanoparticles obtained in [C10mim][Tf 2N].
