- Synthesis, Characterization, and Physicochemical Properties of Hydrophobic Pyridinium-based Ionic Liquids with N-Propyl and N-Isopropyl
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Synthesis and physicochemical properties of four pyridinium-based ionic liquids (ILs), N-propylpyridinium bromide [N-propylPyr]+[Br]–, N-isopropylpyridinium bromide [N-isopropylPyr]+[Br]–, N-propylpyridinium hexafluorophosphate [N-propylPyr]+[PF6]–, and N-isopropylpyridinium hexafluorophosphate [N-isopropylPyr]+[PF6]– are reported. The molecular structures of these compounds were characterized by FT-IR, 1H, 19F, and 31P NMR, spectroscopy. The thermal properties, conductivity, and solubility of these ionic liquids were also investigated. The effects of propyl and isopropyl alkyl lateral chain at the N-position of pyridinium cation on the thermal stability, conductivity, and solubility of ionic liquids are discussed. The results obtained confirmed that the ionic liquids based on pyridinium cations exhibit higher decomposition temperature, low melting points, immiscible with water, and their conductivities are mainly influenced by mobility of ions.
- Matandabuzo, Mzukisi,Ajibade, Peter A.
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- Preparation of Ionic Liquid 1-Propylpyridinium Bromide [C3py]Br and the Molar Surface Quasi-Gibbs Energy Model of Its Aqueous Solution
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The density and surface tension values of aqueous 1-propylpyridinium bromide [C3py]Br at concentrations between 0.0099 and 1.0337 mol·kg–1 were measured at T = (288.15–318.15) K with an interval of 5 K, and the molar surface quasi-Gibbs energy model of aqueous [C3py]Br was established, and the relationships among the molar surface quasi-Gibbs energy, molality, and temperature were also explored. Moreover, the Eo?tvo?s equation was improved in terms of the molar surface quasi-Gibbs energy model.
- He, Jiajia,Meng, Xuelian,Xu, Chengbin
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- Bromobismuthates: Cation-induced structural diversity and Hirshfeld surface analysis of cation–anion contacts
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Reactions of [BiBr6]3? and bromide salts of various substituted pyridinium cations in excess of HBr result in a series of bromobismuthate anionic complexes of various geometry and nuclearity: [{BiBr4}n]n?, [Bi2Br9]3? and [Bi2Br10]4?. Hirshfeld surface analysis for 19 crystal structure was performed; impact of various X-Br contacts on the crystal structures is discussed.
- Adonin, Sergey A.,Gorokh, Igor D.,Novikov, Alexander S.,Samsonenko, Denis G.,Korolkov, Ilya V.,Sokolov, Maxim N.,Fedin, Vladimir P.
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p. 282 - 288
(2017/11/27)
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- Synthesis and surface functionalization of multi-walled carbon nanotubes with imidazolium and pyridinium-based ionic liquids: Thermal stability, dispersibility and hydrophobicity characteristics
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Functionalized multi-walled carbon nanotubes (MWCNTs) were synthesized by simple chemical method, and dispersed using imidazolium and pyridinium-based ionic liquids (ILs). The as-synthesized ILs-MWCNT composites were studied using FTIR spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), thermogravimetric analysis (TGA), and solubility in different polar and non-polar solvents. Spectroscopic and microscopy analyses confirmed the formation of the ILs-MWCNT composites with new functionalities. Spectra studies showed graphitic and carboxylic groups in the pure MWCNTs. MWCNT SEM images showed entangled bundles, while ILs-MWCNTs showed debundled composites with increased diameter and unaltered MWCNTs morphology. TGA indicates that the MWCNTs are thermally stable which could be ascribed to van der Waals and non-covalent interactions within the composites matrices. Solubility studies indicate the ILs-MWCNT composites are hydrophobic, insoluble in water and other polar solvents.
- Matandabuzo, Mzukisi,Ajibade, Peter A.
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p. 284 - 293
(2018/07/29)
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- Does alkyl chain length really matter? Structure-property relationships in thermochemistry of ionic liquids
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DSC was used for determination of reaction enthalpies of synthesis of ionic liquids [Cnmim][Cl]. A combination of DSC with quantum chemical calculations presents an indirect way to study thermodynamics of ionic liquids. The indirect procedure for vaporization enthalpy was validated with the direct experimental measurements by using thermogravimetry. First-principles calculations of the enthalpy of formation in the gaseous phase have been performed for the ionic species using the CBS-QB3 and G3 (MP2) theory. Experimental DSC data for homologous series of alkyl substituted imidazolium, pyridinium, and pyrrolidinium based ionic liquids with anions [Cl] and [Br] were collected from the literature. We have shown that enthalpies of formation, enthalpies of vaporization, and lattice potential energies are linearly dependant on the alkyl chain length. The thermochemical properties of ILs generally obey the group additivity rules and the values of the additivity parameters for enthalpies of formation and vaporization seem to be very close to those for molecular compounds.
- Verevkin, Sergey P.,Zaitsau, Dzmitry H.,Emel'Yanenko, Vladimir N.,Ralys, Ricardas V.,Yermalayeu, Andrei V.,Schick, Christoph
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- Physicochemical properties of ionic liquids [C3py][NTf 2] and [C6py][NTf2]
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Air- and water-stable hydrophobic ionic liquids N-alkylpyridinium bis(trifluoromethylsulfonyl)imide ([Cnpy][NTf2], n = 3, 6) were synthesized. The density, surface tension, dynamic viscosity, and electrical conductivity of [C6py][NTf2] were measured in the range of T = (283.15 to 338.15) K. The density, dynamic viscosity, and electrical conductivity of [C3py][NTf2] were measured in the range of T = (308.15 to 338.15) K. The melting and glass transition temperatures of the two ILs were determined according to the differential scanning calorimetry (DSC). The physicochemical properties, including molecular volume, standard molar entropy, lattice energy, parachor, molar enthalpy of vaporization, interstice volume, interstice fraction, and thermal expansion coefficient, were estimated in terms of empirical and semiempirical equations, as well as the interstice model theory on the base of the experimental values. The dynamic viscosity and electrical conductivity values were fitted by Vogel-Fulcher-Tammann (VFT) and Arrhenius equations for [C6py] [NTf2] and the Arrhenius equation for [C3py][NTf 2].
- Liu, Qing-Shan,Yang, Miao,Li, Pei-Pei,Sun, Si-Si,Welz-Biermann, Urs,Tan, Zhi-Cheng,Zhang, Qing-Guo
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scheme or table
p. 4094 - 4101
(2012/02/15)
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- Thermochemistry of alkyl pyridinium bromide ionic liquids: Calorimetric measurements and calculations
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Two ionic liquids, 1-ethylpyridinium bromide (EPBr) and 1-propylpyridinium bromide (PPBr), were prepared and the structures were characterized by 1H NMR. The thermodynamic properties of EPBr and PPBr were studied with adiabatic calorimetry (AC) and thermogravimatric analysis (TG-DTG). The heat capacity was precisely measured in the temperature range from 78 to 410 K by means of a fully automated adiabatic calorimeter. For EPBr, the melting temperature, enthalpy, and entropy of solid-liquid phase transition were determined to be 391.31 ± 0.28 K, 12.77 ± 0.09 kJ · mol-1, and 32.63 ± 0.22 J-K-1-mol-1, respectively, and for PPBr they were 342.83 ± 0.69 K, 10.97 ± 0.05 kJ-mol-1, and 32.00 ± 0.10 J-K-1TnOn-1, respectively. The thermodynamic functions (HT° - H 298.15°) and (ST° - S298.15°) were derived from the heat capacity data in the experimental temperature range with an interval of 5 K. The thermostablility of the compounds was further studied by TGA measurements. The phase change behavior and thermodynamic properties were compared and estimated in a series of alkyl pyridinium bromide ionic liquids. Results indicate that EPBr has higher melting and decomposition temperature, as well as phase transition enthalpy and entropy but lower heat capacity than PPBr due to their different molecular structures.
- Tong, Bo,Liu, Qing-Shan,Tan, Zhi-Cheng,Welz-Biermann, Urs
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experimental part
p. 3782 - 3787
(2010/08/05)
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- Microwave-assisted synthesis of room-temperature ionic liquid precursor in closed vessel
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We report here the synthesis of various alkylpyridinium and 1-alkyl-3-methylimidazolium halides on a large scale under microwave irradiation, in a closed vessel. The reaction time was drastically reduced as compared to conventional methods, and good yields were obtained.
- Khadilkar, Bhushan M.,Rebeiro, Geeta L.
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p. 826 - 828
(2013/09/06)
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