Preparation, cation-anion interactions and physicochemical properties of ether-functionalized imidazolium ionic liquids (original) (raw)
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Journal de Chimie Physique et de Physico-Chimie Biologique, 1998
La reaction du chlonue de I-n-butyl-3-mCthylimidazolium (BMI.CI) avec le tetrafluoroborate ou l'hexafluoropliosphate de sodium produit les sels fondus B M . X (1, X = BF4 et 2, X = PFb). Les composes 1 et 2 sont des liquides visqueux dans une grande gamme de temperature (jusqu'a 192 K). Les analyses par XR et RMN ('H et '"C), densite, viscosite et conductivite suggerent que le compose 2 presente un comportement quasi-moleculaire. Le colnpose l est quasi-molecdaire en dessous de 279 K, mais a plus hautes temperat~ues il est probableinent sous une forme ionique qui resulte d'interactions entre les ions i~nidazolium et tetrafluoroborate a travers des liasons du type pont d'hydrogene.
Green Chemistry, 2001
A series of hydrophilic and hydrophobic 1-alkyl-3-methylimidazolium room temperature ionic liquids (RTILs) have been prepared and characterized to determine how water content, density, viscosity, surface tension, melting point, and thermal stability are affected by changes in alkyl chain length and anion. In the series of RTILs studied here, the choice of anion determines water miscibility and has the most dramatic effect on the properties. Hydrophilic anions (e.g., chloride and iodide) produce ionic liquids that are miscible in any proportion with water but, upon the removal of some water from the solution, illustrate how sensitive the physical properties are to a change in water content. In comparison, for ionic liquids containing more hydrophobic anions (e.g., PF 6 2 and N(SO 2 CF 3 ) 2 2 ), the removal of water has a smaller affect on the resulting properties. For a series of 1-alkyl-3-methylimidazolium cations, increasing the alkyl chain length from butyl to hexyl to octyl increases the hydrophobicity and the viscosities of the ionic liquids increase, whereas densities and surface tension values decrease. Thermal analyses indicate high temperatures are attainable prior to decomposition and DSC studies reveal a glass transition for several samples. ILs incorporating PF 6 2 have been used in liquid/liquid partitioning of organic molecules from water and the results for two of these are also discussed here. On a cautionary note, the chemistry of the individual cations and anions of the ILs should not be overlooked as, in the case of certain conditions for PF 6 2 ILs, contact with an aqueous phase may result in slow hydrolysis of the PF 6 2 with the concomitant release of HF and other species.
Journal of Physical Chemistry B, 2008
Physical properties of 4 room-temperature ionic liquids consisting of the 1-butyl-3-methylimidazolium cation with various perfluorinated anions and the bis(trifluoromethylsulfonyl)imide (Tf 2 N -) anion with 12 pyrrolidinium-, ammonium-, and hydroxyl-containing cations are reported. Electronic structure methods are used to calculate properties related to the size, shape, and dipole moment of individual ions. Experimental measurements of phase-transition temperatures, densities, refractive indices, surface tensions, solvatochromic polarities based on absorption of Nile Red, 19 F chemical shifts of the Tf 2 Nanion, temperature-dependent viscosities, conductivities, and cation diffusion coefficients are reported. Correlations among the measured quantities as well as the use of surface tension and molar volume for estimating Hildebrand solubility parameters of ionic liquids are also discussed.
Journal of Chemical & Engineering Data
In this work, a series of imidazolium-based ionic liquids with varying functionalities from aliphatic to aromatic groups and a fixed anion, bis[(trifluoromethane)sulfonyl]amide, were investigated. The imidazolium cations included 1-heptyl-3-methylimidazolium, 1-(cyclohexylmethyl)-3-methylimidazolium, 1-benzyl-3-methylimidazolium, 1,3-dibenzylimidazolium, and 1-(2-naphthylmethyl)-3-methylimidazolium. Structureproperty relationships were investigated regarding the substituent effects on the imidazolium cation, including n-alkyl versus cycloalkyl and aromatic versus aliphatic, as well as the effects of cation symmetry and larger aromatic polycyclic functionalities. Thermophysical properties investigated include density, thermal transition temperatures, and decomposition temperatures. The densities of the ionic liquids are governed by the substituents on the cation: n-alkyl < cycloalkyl < aromatic. The group contribution method is applicable for the density estimation of ionic liq...
The journal of physical chemistry. B, 2015
This work presents and highlights the differentiation of the physicochemical properties of the [C1Him][NTf2], [C2Him][NTf2], [1C12C1Him][NTf2], and [1C42C13C1im][NTf2] that are related with the strong bulk interaction potential, which highlights the differentiation on the physicochemical arising from the presence of the acidic group (N-H) as well as the methylation in position 2 (C(2)) of the imidazolium ring. Densities, viscosities, refractive indices and surface tensions in a wide range of temperatures, as well as, isobaric heat capacities at 298.15 K, for this IL series are presented and discussed. It was found that the volumetric properties are barely affected by the geometric and structural isomerization, following a quite regular trend. A linear correlation between the glass transition temperature, Tg, and the alkyl chain size was found; however, ILs with the acidic N-H group present a significant higher Tg than the [1CN-13C1im][NTf2] and [1CN3CNim][NTf2] series. It was found ...
Preparation and Characterization of New Room Temperature Ionic Liquids
Chemistry-a European Journal, 2002
A new series [C n O m mim][X] of imidazolium cation-based room temperature ionic liquids (RTILs), with ether and alcohol functional groups on the alkyl side-chain has been prepared. Some physical properties of these RTILs were measured, namely solubility in common solvents, viscosity and density. The solubility of LiCl, HgCl 2 and LaCl 3 in room temperature ionic liquids was also determined. The features of the solid ± liquid phase transition were analysed, namely the glass transition temperature and the heat capacity jump associated with the transition from the non-equilibrium glass to the metastable supercooled liquid. These properties were compared with those reported for the 1-n-alkyl-3-methylimidazolium [C n mim][X] series. While the density and solid ± liquid phase transition properties are similar for both series, the new RTILs present a considerably lower viscosity and an increased ability to dissolve HgCl 2 and LaCl 3 (up to 16 times higher).