Showing papers on "Ionic liquid published in 1993"
TL;DR: In this paper, the authors used an extended X-ray absorption fine structure (EXAFS) study in ambient-temperature ionic liquids to characterize two distinct anions with differing interactions within the extended hydrogen-bonded structures.
Abstract: The novel salts [emim]2[CoCl4] and [emim]2[NiCl4](emim = 1-ethyl-3-methylimidazolium cation) have been prepared for use as crystallographic models in an extended X-ray absorption fine structure (EXAFS) study in ambient-temperature ionic liquids. The salts have been characterized both spectroscopically and crystallographically. The crystals are isomorphous, and contain two distinct anions with differing interactions within the extended hydrogen-bonded structures. The implications of these results for the structure of ambient-temperature ionic liquids are discussed.
182 citations
TL;DR: In this article, the authors used a sample inlet system for air-sensitive materials to study 1-ethyl-3-methylimidazolium chloride-aluminium(III) chloride ([emim]Cl−AlCl3) ionic liquids.
Abstract: Previous studies of 1-ethyl-3-methylimidazolium chloride–aluminium(III) chloride ([emim]Cl–AlCl3) ionic liquids have been hampered by significant contamination of these liquids by oxide impurities. Treatment of these liquids with phosgene removes the oxide impurities, and the use of a specially constructed sample inlet system for air-sensitive materials permitted them to be studied by fast atom bombardment mass spectrometry. The ions Cl−, [Cl2]−, [AlCl4]−, [Al2Cl7]−, [emim]+ and [(emim)2X]+ (X = Cl or AlCl4) were observed for the basic ionic liquid. In addition, the anion [Al3Cl10]− was observed for the acidic composition. Within the mass spectrometer, the hydrolyses of [Al3Cl10]− to produce [Al3Cl8O]− and of [Al2Cl7]− to produce [Al2Cl5O]− were observed. Comparison of these results with published 17O NMR data suggests that the primary hydrolysis products in acidic ionic liquids are [Al3Cl8O]− and [Al2Cl5O]− and that the principal secondary hydrolysis product is [Al2Cl6(OH)]−.
66 citations
01 Aug 1993
TL;DR: In this article, the authors report on static and dynamic light scattering measurements of near-critical fluctuations of an ionic liquid, which exhibits a liquid-liquid phase transition in the salt rich regime with an upper critical point near 315 K at a mole fraction of the salt x 1 = 0.773.
Abstract: We report on static and dynamic light scattering measurements of near-critical fluctuations of an ionic liquid. The system is ethylammonium nitrate (EAN) dissolved in n-octanol which exhibits a liquid-liquid phase transition in the salt rich regime with an upper critical point near 315 K at a mole fraction of the salt x1 = 0.773. The correlation lengths and scattering intensities scale with temperature corresponding to an Ising-like critical point. This contrasts with previous observations of mean-field behaviour in electrolyte systems with liquid-liquid phase transitions driven by long-range Coulombic interactions. Rationalizations of this discrepancy are offered taking into account a) the competition of intermolecular interactions with long-range and short-range character and b) the possibility of crossover from mean-field to Ising behaviour as predicted by the Landau-Ginzburg theory.
45 citations
TL;DR: In this paper, a novel salt [emim]2[VOCl4] ([emim]+ = 1-ethyl-3-methylimidazolium cation has been prepared and characterized, both spectroscopically and crystallographically.
36 citations
TL;DR: In this article, the properties of both dilute solutions of oxygen in Cr-Fe liquid alloys and liquid oxides were represented by a single two-sublattice ''ionic liquid» model.
Abstract: The thermodynamic properties and phase relationships in the Cr-Fe-O system have been critically assessed. The solid oxide phases have been represented using the «compound energy» model, which allows the introduction of non-stoichiometry, lattice vacancies, interstitial ions and exchange of ions between different sublattices in a formally very simple way. The properties of both dilute solutions of oxygen in Cr-Fe liquid alloys and liquid oxides were represented by a single two-sublattice «ionic liquid» model. The modelling is limited by the experimental data available but aims to cover the temperature range 298 K to about 2600 K
35 citations
Patent•
04 Feb 1993
TL;DR: In this article, a process for the polymerization of an olefinic feedstock comprising one or more of butene, butene-2 and iso-butene by bringing the feedstock into contact with an ionic liquid comprising a) an aluminium compound of the formula Rn AlX3-n wherein R is a C1-C6 alkyl radical, X is a halogen atom and n is 0, 1 or 2, and b) a substituted imidazolium and/or a substituted pyridinium halide such that the
Abstract: This invention relates to a process for the polymerization of an olefinic feedstock comprising one or more of butene-1, butene-2 and iso-butene by bringing the feedstock into contact with an ionic liquid comprising a) an aluminium compound of the formula Rn AlX3-n wherein R is a C1-C6 alkyl radical, X is a halogen atom and n is 0, 1 or 2, and b) a substituted imidazolium and/or a substituted pyridinium halide such that the melting point of the ionic liquid is below the reaction temperature in the range from -50° C. to +100° C. The polymers so produced can be used to react with alkenyl succinimides which are useful fuel and lubricating oil additives.
32 citations
28 citations
TL;DR: In this paper, the authors concluded that proton speciation in these liquids is governed largely by the reaction H 2 Cl 3 +Cl - ⇄2HCl 2 -, for which the stoichiometric equilibrium constant has been evaluated as 218±25; the concentration of molecular HCl is small or negligible relative to that of the anionic species.
Abstract: Ionic equilibria associated with acidic protons present in HCl:ImCl (Im + ≡1-ethyl-3-methyl-1H-imidazolium) ionic liquids (0.38
27 citations
TL;DR: In this article, the role of doping of macromolecules generated in the process of polyphenylene synthesis is considered and a hypothesis is proposed to analyze the effect of doping on the structure and molecular mass of the samples.
12 citations
TL;DR: In this article, a poly(p)-phenylene with degree of polymerization higher than 35 was obtained by oxidative polymerization of benzene in an aluminum chloride and N -butylpyridinium chloride based ionic liquid.
10 citations
TL;DR: In this article, the hydrogen chloride/dichloride equilibrium was examined by 2H and 'H NMR spectroscopies, and an equilibrium isotope effect of 0.67 f 0.7 12 was calculated from hydrogen chloride and hydrogen dichloride vibrational frequencies.
Abstract: In basic mixtures of the molten salt composed of aluminum chloride and 1 -ethyl-3-methylimidazolium chloride, proton, in the absence of oxides, is partitioned between hydrogen chloride and hydrogen dichloride ion. The equilibrium between these two species has been examined by 2H and 'H NMR spectroscopies. The magnitude of the hydrogen chloride/dichloride equilibrium constant demonstrates that the equilibrium strongly favors the formation of the hydrogen dichloride ion. The ratio of 2H and IH equilibrium constants at 90 OC gave an equilibrium isotope effect of 0.67 f 0.26, which indicates that deuterium accumulates in the hydrogen chloride molecule. An equilibrium isotope effect of 0.7 12 was calculated from hydrogen chloride and hydrogen dichloride vibrational frequencies. Analysis of the temperature dependence of the hydrogen chloride/dichloride equilibrium constant gave values for the enthalpy of reaction, MMN, and the entropy of reaction, LS", of -9.8 f 0.8 kJ mol-' and 4.8 f 2.5 J mol-' K-1, respectively. Comparison of the AH" for the hydrogen chloride/dichloride equilibrium in the melts with values obtained for other solvents suggests that the melt interacts more strongly with chloride ion than with hydrogen dichloride ion.
TL;DR: In this article, the authors used multinuclear NMR (13C and 17O) spectroscopy and mass spectrometry to investigate the removal of oxide impurities in the form of carbon dioxide.
Abstract: Treatment of ambient-temperature chloroaluminate(III) ionic liquids with phosgene results in the removal of oxide impurities in the form of carbon dioxide; the reaction was investigated using multinuclear NMR (13C and 17O) spectroscopy and mass spectrometry. Both the CO2 and the excess of phosgene are removed in vacuo to leave the ionic liquid free from oxide contamination.
TL;DR: In this paper, both nonionic and ionic liquid-crystalline side-chain polymer [P(A-CH3)) and the ionic family [P[CH3/CH3I] of P(A−CH3) were prepared.
Abstract: Both nonionic liquid-crystalline side-chain polymer [P(A—CH3)) and ionic family [P(A—CH3/CH3I)] of P(A–CH3) were prepared. Nonionic P(A—CH3), having an alkylamine spacer, exhibited solidsmectic and smectic-isotropic phase transitions. Ionic P(A—CH3/CH3I), having an alkylammonium spacer, showed glassy-smectic and smectic-isotropic phase transitions. Ionic P(A—CH3/CH3I) exhibited the enhanced thermal stability by the aggregation of ammonium ions formed by Coulomb's force in comparison with nonionic P(A—CH3). The enhanced thermal stability in ionic families was also concluded from experimental results obtained for nonionic and ionic low molecular weight liquid-crystalline compounds corresponding to mesogenic side groups of P(A—CH3) and P(A—CH3/CH3I).
TL;DR: An ionic liquid-crystalline polymethacrylate [P-Pi/MeI having a piperidinium skeleton in a mesogenic side-chain was synthesized.
Abstract: An ionic liquid-crystalline polymethacrylate [P-Pi/MeI having a piperidinium skeleton in a mesogenic side-chain was synthesized. Its nonionic family [P-Pi was also prepared, and phase transitions of P-Pi/ MeI and P-Pi were compared. Both P-Pi/MeI and P-Pi exhibit enantiotropically smectic phases. Ionic P-Pi/MeI shows enhanced thermal stability in comparison with nonionic P-Pi. A temperature of P-Pi/MeI, at which an isotropic phase forms, is higher than that of P-Pi. P-Pi/MeI also shows a higher glass transition temperature when compared to P-Pi. Also, nonionic and ionic low molecular weight model compounds were prepared, and their thermal properties were compared.
Patent•
15 Feb 1993
TL;DR: In this article, an olefinic feedstock comprising butene, butene-2 and isobutene is contacted with an ionic liquid comprising (A) an aluminum compound of the formula: R n AlX 3-n (R is 1-6C alkyl; X is halogen; and n is 0-2), and (B) a substituted imidazolium halide, preferably 1-methyl-3-ethyl imidazeolium chloride, etc.
Abstract: PURPOSE: To obtain efficiently the title polymer without employing an additional catalyst such as Ni by contacting a feedstock comprising butenes and isobutene with an ionic liquid comprising two specific components as a reaction medium and a catalyst. CONSTITUTION: An olefinic feedstock comprising butene-1, butene-2 and isobutene is contacted with an ionic liquid comprising (A) an aluminum compound of the formula: R n AlX 3-n (R is 1-6C alkyl; X is halogen; and n is 0-2), preferably ethylaluminum dichloride, etc., and (B) a substituted imidazolium halide, preferably 1-methyl-3-ethyl imidazolium chloride, etc., and/or a substituted pyridinium halide, preferably ethyl pyridinium chloride, etc., such that the melting point of the ionic solvent is below the reaction temperature, which is -50-100°C, to cause polymerization. The ratio of the components A to B is preferably 1.5:1-2:1. And the polymerization is preferably carried out at -25-60°C. COPYRIGHT: (C)1993,JPO
TL;DR: In this paper, the electrochemistry of two derivatives of (η 5 -cyclopentadienyl)(1,2-ethylenedithiolato)cobalt(III) complexes with substituents, cyano (CN) and 4-pyridyl ( 4 Py) at the ethylenedithio moiety, was studied at a glassy carbon electrode in an ambient temperature ionic liquid composed of aluminum chloride and 1-ethyl-3-methylimidazolium chloride (AlCl 3 -ImCl).