174899-90-2Relevant articles and documents
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.
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