- Dissolution of oligo(tetrafluoroethylene) and preparation of poly(tetrafluoroethylene)-based composites by using fluorinated ionic liquids
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Fluorophilic ionic liquids (ILs) showing enhanced compatibility with poly(tetrafluoroethylene) (PTFE) have been newly synthesised. The as-designed ILs contributed both to the dissolution of PTFE oligomers and to the preparation of composites with PTFE with no fear of bleed-out of the ILs.
- Tsurumaki, Akiko,Ohno, Hiroyuki
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- A simple and practical method for the preparation and purity determination of halide-free imidazolium ionic liquids
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The reaction of N-alkylimidazole with alkyl sulfonates at room temperature affords 1,3-dialkylimidazolium alkanesulfonates as crystalline solids in high yields. The alkanesulfonate anions can be easily substituted by a series of other anions [BF4, PF6, PF3(CF 2CF3)3, CF3SO3 and N(CF3SO2)2] by simple reaction of anions, salts, or acids in water at room temperature. Extraction with dichloromethane, filtration through a short basic alumina column and solvent evaporation affords the desired ionic liquids in 80-95% yield. The purity (> 99.4%) of these ionic liquids can be determined by 1H NMR spectra using the intensity of the 13C satellites of the imidazolium N-methyl group as internal standard.
- Cassol, Claudia C.,Ebeling, Guenter,Ferrera, Bauer,Dupont, Jairton
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- Rapid, High-Yield Fructose Dehydration to 5-Hydroxymethylfurfural in Mixtures of Water and the Noncoordinating Ionic Liquid [bmim][OTf]
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The noncoordinating ionic liquid [bmim][OTf] (bmim=1-butyl-3-methylimidazolium) is an effective and versatile solvent for the high-yield dehydration of fructose to the platform chemical 5-hydroxymethylfurfural (HMF) over short reaction times. In contrast to prior studies in which low yields were obtained for this transformation in ionic liquids (ILs) with noncoordinating anions, this contribution reveals that the water content is an essential parameter for an efficient reaction in ILs. Achieving the optimum amount of water can increase the yield dramatically by regulating the acidity of the catalyst and partially suppressing the side reaction caused by self-condensation of HMF. Using acid catalysis in [bmim][OTf] with 3.5 % water content, yields above 80 % can be achieved at 100 °C in only 10 min, even at high (14 %) fructose loading. These results also suggest that [bmim][OTf] represents a superior medium for solvent extraction of HMF compared to halide-based ILs, allowing the option of isolation or further valorization of the HMF formed.
- Ghatta, Amir Al,Wilton-Ely, James D. E. T.,Hallett, Jason P.
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- The conductivity of imidazolium-based ionic liquids from (248 to 468) K. B. variation of the anion
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The effect of the anion, namely dicyanamide, hexafluorophosphate, trifluoroacetate, or trifluoromethanesulfonate, on the conductivity (κ) of 1-N-butyl-3-N-methylimidazolium-based room-temperature ionic liquids (RTILs) was studied over the temperature range (248 to 468) K. The uncertainty in κ was estimated to be less than 0.5 %. The conductivity values obtained are well-described by the Vogel-Fulcher-Tammann equation. Additionally, densities (ρ) and the corresponding molar conductivities (Λ) are reported for the temperature range (278 to 338) K. The data for Λ and the associated viscosities (η) were found to fit fractional forms of the Walden relationship.
- Zech, Oliver,Stoppa, Alexander,Buchner, Richard,Kunz, Werner
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- [{Fe(CO)3}4{SnI}6I4] 2-: The first bimetallic adamantane-like cluster
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Show some metal: The first bimetallic adamantane-like cluster, [{Fe(CO)3}4{SnI}6I4]2- (see structure), was prepared by an ionic-liquid-based synthesis. The valence states of iron and tin were verified
- Wolf, Silke,Winter, Florian,P?ttgen, Rainer,Middendorf, Nils,Klopper, Wim,Feldmann, Claus
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- Eu3 + as a dual probe for the determination of IL anion donor power: A combined luminescence spectroscopic and electrochemical approach
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This work is aimed at giving proof that Eu(Tf2N)3 (Tf2N = bis(trifluoromethanesulfonyl)amide) can act as both an optical and electrochemical probe for the determination of the Lewis acidity of an ionic liquid anion. For that reason the luminescence spectra and cyclic voltammograms of dilute solutions of Eu(Tf2N)3 in various ionic liquids were investigated. The Eu2 +/3 + redox potential in the investigated ILs can be related to the Lewis basicity of the IL anion. The IL cation had little influence. The lower the determined halfwave potential, the higher the IL anion basicity. The obtained ranking can be confirmed by luminescence spectroscopy where a bathochromic shift of the 5D 0 → 7F4 transition indicates a stronger Lewis basicity of the IL anion.
- Babai, Arash,Kopiec, Gabriel,Lackmann, Anastasia,Mallick, Bert,Pitula, Slawomir,Tang, Sifu,Mudring, Anja-Verena
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- Theoretical and experimental comparative study of nonlinear properties of imidazolium cation based ionic liquids
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This work describes the experimental and theoretical investigation of the nonlinear optical properties of the imidazolium cation based ionic liquids and the corresponding thermo-optical parameters. The experimental results of nonlinear optical properties, such as nonlinear refractive index and thermo-optical properties are determined by Z-scan and EZ-scan techniques with a femtosecond laser source. Theoretical simulations of linear and nonlinear optical properties performed by density functional theory (DFT) are discussed in terms of polarizabilities and hyperpolarizabilities. A correlation between the theoretical and experimental results is presented, where the variation of the experimental signals of each ionic liquid can be compared with their calculated nonlinear optical properties.
- Ferreira, Vinícius Castro,Zanchet, Letícia,Monteiro, Wesley Formentin,da Trindade, Letícia Guerreiro,de Souza, Michèle Oberson,Correia, Ricardo Rego Bordalo
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- Physical and electrochemical properties of ionic liquids 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium trifluoromethanesulfonate and 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide
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The ionic liquids 1-ethyl-3-methylimidazolium tetrafluoroborate 1-butyl-3-methylimidazolium trifluoromethanesulfonate and 1-butyl-1- methylpyrrolidinium bis(trifluoromethylsulfonyl)imide were prepared and several of their properties including viscosities, thermal stability, surface tension, refractive index, pH and density were investigated as a function of temperature. The coefficients of thermal expansion of the ionic liquids were also calculated from the experimental values of the density at various temperatures. The electrochemical stability of the ionic liquids, as electrolytes for voltammetric aspects, was studied at glassy carbon electrode. The results revealed a wide voltage range of the electrochemical window, which allowed studies on compounds such as furaldehydes.
- Shamsipur, Mojtaba,Beigi, Ali Akbar Miran,Teymouri, Mohammad,Pourmortazavi, Sayed Mahdi,Irandoust, Mohsen
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- Determination of halide impurities in ionic liquids by total reflection X-ray fluorescence spectrometry
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The determination and quantification of halide impurities in ionic liquids is highly important because halide ions can significantly influence the chemical and physical properties of ionic liquids. The use of impure ionic liquids in fundamental studies on solvent extraction or catalytic reactions can lead to incorrect experimental data. The detection of halide ions in solution by total reflection X-ray fluorescence (TXRF) has been problematic because volatile hydrogen halide (HX) compounds are formed when the sample is mixed with the acidic metal standard solution. The loss of HX during the drying step of the sample preparation procedure gives imprecise and inaccurate results. A new method based on an alkaline copper standard Cu(NH3) 4(NO3)2 is presented for the determination of chloride, bromide, and iodide impurities in ionic liquids. The 1-butyl-3-methylimidazolium ([C4mim]) ionic liquids with the anions acetate ([C4mim][OAc]), nitrate ([C4mim][NO3]), trifluoromethanesulfonate ([C4mim][OTf]), and bis(trifluoromethylsulfonyl)imide ([C4mim][Tf2N]) were synthesized via a halide-free route and contaminated on purpose with known amounts of [C4mim]Cl, [C4mim]Br, [C4mim]I, or potassium halide salts in order to validate the new method and standard.
- Vander Hoogerstraete, Tom,Jamar, Steven,Wellens, Sil,Binnemans, Koen
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- Densities and viscosities of 1-butyl-3-methylimidazolium trifluoromethanesulfonate + H2O binary mixtures at T = (303.15 to 343.15) K
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Densities and viscosities for the binary mixtures of H2O (1) + 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([BMIM][CF 3SO3]) (2) were measured over the entire mole fraction range from (303.15 to 343.15) K at atmospheric pressure. Excess molar volumes and viscosity deviations as a function of mole fraction average were derived, and the results were fitted to the Redlich-Kister equation using a multiparametric nonlinear regression method. Estimated coefficients of the Redlich-Kister equation and standard error calculated from the Redlich-Kister equation to the experimental data are also presented. The results show that the densities and viscosities are dependent on water content and temperature.
- Ge, Ming-Lan,Zhao, Ru-Song,Yi, Yu-Feng,Zhang, Qi,Wang, Li-Sheng
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- An environmentally benign attribute for the expeditious synthesis of quinoxaline and its derivatives
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A simple, efficient, and environmentally friendly ionic liquid mediated protocol for the synthesis of quinoxaline derivatives using carbonyl substrate and phenylenediamines has been described. A range of ionic liquids were synthesized, characterized via IR, 1H and 13C NMR and used as a solvent as well as catalyst for above protocol. The catalytic activities of ILs were evaluated and the relationship between the catalytic activity and acidity was discussed. It was also found that among the all ILs, [Bmim]CF3SO3 was the most effective, eco-friendly and less expensive solvent and catalyst for the above etiquette. This method is of significant value due to the eco-friendly nature of ionic liquid and non usage of separate catalyst to drive the reaction forward. The protocol proves to be efficient and environmentally benign in terms of good to excellent yields, low reaction times, simple work-up, ease of recovery, and reusability of ionic liquid for six times.
- Bhargava, Sangeeta,Soni,Rathore, Deepti
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- Correlating ionic liquid solvent effects with solvent parameters for a reaction that proceeds through a xanthylium intermediate
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A unimolecular nucleophilic substitution reaction that proceeds through a xanthylium carbocation was studied in seven ionic liquid solvents. It was found that the general trend in the rate constant with changing proportion of ionic liquid in the reaction mixture was different to that seen for other unimolecular processes, with the rate constant increasing as more ionic liquid was added to the reaction mixture. A significant correlation was found between the natural logarithm of the rate constant and a combination of the Kamlet-Taft solvent parameters. This relationship indicated that the principal interaction involved hydrogen bonding between the ionic liquid and some species along the reaction coordinate. Further, this correlation enables prediction of the effects that other ionic liquids will have on this, and other, reactions that proceed through a similar intermediate.
- Gilbert, Alyssa,Bucher, G?tz,Haines, Ronald S.,Harper, Jason B.
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supporting information
p. 9336 - 9342
(2019/11/13)
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- The effect of varying the anion of an ionic liquid on the solvent effects on a nucleophilic aromatic substitution reaction
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A variety of ionic liquids, each containing the same cation but a different anion, were examined as solvents for a nucleophilic aromatic substitution reaction. Varying the proportion of ionic liquid was found to increase the rate constant as the mole fraction of ionic liquid increased demonstrating that the reaction outcome could be controlled through varying the ionic liquid. The solvent effects were correlated with the hydrogen bond accepting ability (β) of the ionic liquid anion allowing for qualitative prediction of the effect of changing this component of the solute. To determine the microscopic origins of the solvent effects, activation parameters were determined through temperature-dependent kinetic analyses and shown to be consistent with previous studies. With the knowledge of the microscopic interactions in solution, an ionic liquid was rationally chosen to maximise rate enhancement demonstrating that an ionic solvent can be selected to control reaction outcome for this reaction type.
- Hawker, Rebecca R.,Haines, Ronald S.,Harper, Jason B.
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supporting information
p. 3453 - 3463
(2018/05/23)
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- Method for synthesizing antioxygen 1076
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The invention belongs to the technical field of fine chemistry and particularly relates to a method for synthesizing antioxygen 1076. The method is prepared by carrying out an ester exchange reaction on raw materials including beta-(3,5-ditert-butyl-4-hydroxyphenyl)methyl propionate and octadecanol; the ester exchange reaction is carried out in a neutral/weakly alkaline ionic liquid catalysis system. According to the method provided by the invention, neutral/weakly alkaline ionic liquid is used as a catalyst and the catalysis performance is good; the content of final products reaches 99% or more and the yield reaches 97.5% or more. In a 1076 esterification reaction, performances of the neutral/weakly alkaline ionic liquid catalyst are better than catalysts including sodium methylate, potassium tert-butanolate, organic tin, organic titanium and the like. By utilizing the ionic liquid catalysis system, post-treatment operation is simple; the catalyst is environmentally friendly and the catalyst can be circularly utilized; and the product has a good color and high yield.
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Paragraph 0022
(2017/07/21)
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- The impact of ionic liquids on the coordination of anions with solvatochromic copper complexes
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Solvatochromic transition metal (TM)-complexes with weakly associating counter-anions are often used to evaluate traditional neutral solvent and anion coordination ability. However, when employed in ionic liquids (IL) many of the common assumptions made are no longer reliable. This study investigates the coordinating ability of weakly coordinating IL anions in traditional solvents and within IL solvents employing a range of solvatochromic copper complexes. Complexes of the form [Cu(acac)(tmen)][X] (acac = acetylacetonate, tmen = tetramethylethylenediamine) where [X]- = [ClO4]-, Cl-, [NO3]-, [SCN]-, [OTf]-, [NTf2]- and [PF6]- have been synthesised and characterised both experimentally and computationally. ILs based on these anions and imidazolium and pyrrolidinium cations, some of which are functionalised with hydroxyl and nitrile groups, have been examined. IL-anion coordination has been investigated and compared to typical weakly coordinating anions. We have found there is potential for competition at the Cu-centre and cases of anions traditionally assigned as weakly associating that demonstrate a stronger than expected level of coordinating ability within ILs. [Cu(acac)(tmen)][PF6] is shown to contain the least coordinating anion and is established as the most sensitive probe studied here. Using this probe, the donor numbers (DNs) of ILs have been determined. Relative donor ability is further confirmed based on the UV-Vis of a neutral complex, [Cu(sacsac)2] (sacsac = dithioacetylacetone), and DNs evaluated via23Na NMR spectroscopy. We demonstrate that ILs can span a wide donor range, similar in breadth to conventional solvents.
- Kuzmina,Hassan,Patel,Ashworth,Bakis,White,Hunt,Welton
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supporting information
p. 12185 - 12200
(2017/09/25)
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- Catalytic pyrolysis of cellulose in ionic liquid [bmim]OTf
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This study discussed the catalytic cracking process of cellulose in ionic liquid 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([bmim]OTF) under 180 °C, 240 °C and 340 °C, found that [bmim]OTF is an effective catalyst which can effectively reduce the pyrolysis temperature(nearly 200 °C) of the cellulose. FRIR, XRD and SEM were used to analyze the structure characterization of fiber before and after the cracking; GC-MS was used for liquid phase products analysis; GC was used to analyze gas phase products. The results showed that the cellulose pyrolysis in [bmim]OTf mainly generated CO2, CO and H2, also generated 2-furfuryl alcohol, 2,5-dimethyl-1,5-diallyl-3-alcohol, 1,4-butyrolactone, 5-methyl furfural, 4-hydroxy butyric acid, vinyl propionate, 1-acetoxyl group-2-butanone, furan formate tetrahydrofuran methyl ester liquid product, and thus simulated the evolution mechanism of cellulose pyrolysis products based on the basic model of cellulose monomer.
- Qu, Guangfei,He, Weiwei,Cai, Yingying,Huang, Xi,Ning, Ping
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p. 390 - 396
(2016/05/19)
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- One-pot water-free ionic liquids synthesis using trialkyl orthoesters
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The present invention relates to a manufacturing method of an ionic liquid, including a step of manufacturing an amine based compound or a heterocyclic compound including alkylated nitrogen made by making a negative ion salt compound and trialkyl ortho esters react with at least one among heterocyclic compounds with nitrogen and amine based compounds.COPYRIGHT KIPO 2015
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Paragraph 0108-0112
(2016/10/10)
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- A general and direct synthesis of imidazolium ionic liquids using orthoesters
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A general method to synthesize halide and halide-free ionic liquids was developed. Direct alkylation of imidazole and pyridine derivatives was performed in the presence of an acid using an orthoester as the alkyl donor yielding ionic liquid products. Residual Cl and water contents of the ionic liquids were determined by ion chromatography and a Karl-Fisher test. the Partner Organisations 2014.
- Kim, Do Joong,Oh, Kyung Hwan,Park, Jin Kyoon
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supporting information
p. 4098 - 4101
(2014/11/07)
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- Improvement of the Friedel-Crafts benzoylation by using bismuth trifluoromethanesulfonate in 1-butyl-3-methylimidazolium trifluoromethanesulfonate ionic liquid under microwave irradiation
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Bismuth trifluoromethanesulfonate (bismuth triflate) catalyzed the Friedel-Crafts benzoylation of activated aromatic compounds when dissolved in 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([BMIM]OTf) ionic liquid. Immobilization of bismuth triflate (5 mol %) in [BMIM]OTf allowed the synthesis of aryl ketones in good to excellent yields with short reaction times under microwave irradiation. This catalytic system was easily recovered and reused several times without any significant loss of the activity.
- Hoangtran, Phuong,Bichle Do, Ngoc,Ngocle, Thach
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p. 205 - 208
(2014/01/06)
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- A simple halide-to-anion exchange method for heteroaromatic salts and ionic liquids
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A broad and simple method permitted halide ions in quaternary heteroaromatic and ammonium salts to be exchanged for a variety of anions using an anion exchange resin (A- form) in non-aqueous media. The anion loading of the AER (OH- form) was examined using two different anion sources, acids or ammonium salts, and changing the polarity of the solvents. The AER (A- form) method in organic solvents was then applied to several quaternary heteroaromatic salts and ILs, and the anion exchange proceeded in excellent to quantitative yields, concomitantly removing halide impurities. Relying on the hydrophobicity of the targeted ion pair for the counteranion swap, organic solvents with variable polarity were used, such as CH3OH, CH3CN and the dipolar nonhydroxylic solvent mixture CH3CN:CH2Cl 2 (3:7) and the anion exchange was equally successful with both lipophilic cations and anions.
- Alcalde, Ermitas,Dinares, Immaculada,Ibanez, Anna,Mesquida, Neus
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experimental part
p. 4007 - 4027
(2012/07/28)
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- Standard pKa scales of carbon-centered indicator acids in ionic liquids: Effect of media and structural implication
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Energetics of bond dissociation, especially the R-H bond heterolysis free energy (pKa), has played a central role in promoting chemistry to become a rational science. Despite the oceans of acidity studies in the literature, the current knowledge is limited to that in the classical molecular solvents and is unable to be extended to anticipate the acidity changes in ionic media. As the latter is now very popular for replacing volatile organic solvents, it becomes highly desirable to know how the driving force of bond cleavage is varied as the medium composition is switched from neutral molecules to the charged ions. Here we describe a general approach to measure absolute pKa's in pure ionic liquid (IL). The standard conditions warranting accurate measurement were outlined. The pKa's of the selected 18 C-H type indicator acids in four ILs were determined and a convenient indicator platform was constructed for easy expansion of acidity scales. These absolute pKa's make possible, for the first time, direct comparisons of bond energies in IL with those in molecular solvent and in the gas phase and should be able to serve as the standard parameters for calibrating computational methods suitable for the studies in ionic media. The effect of cation and anion in IL in relation to structure was analyzed.
- Deng, Hui,Li, Xin,Chu, Yuan,He, Jiaqi,Cheng, Jin-Pei
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p. 7291 - 7298
(2012/11/07)
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- Ionic-liquid-mediated active-site control of MoS2 for the electrocatalytic hydrogen evolution reaction
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The layered crystal MoS2 has been proposed as an alternative to noble metals as the electrocatalyst for the hydrogen evolution reaction (HER). However, the activity of this catalyst is limited by the number of available edge sites. It was previously shown that, by using an imidazolium ionic liquid as synthesis medium, nanometre-size crystal layers of MoS2 can be prepared which exhibit a very high number of active edge sites as well as a de-layered morphology, both of which contribute to HER electrocatalytic activity. Herein, it is examined how to control these features synthetically by using a range of ionic liquids as synthesis media. Non-coordinating ILs with a planar heterocyclic cation produced MoS2 with the de-layered morphology, which was subsequently shown to be highly advantageous for HER electrocatalytic activity. The results furthermore suggest that the crystallinity, and in turn the catalytic activity, of the MoS2 layers can be improved by employing an IL with specific solvation properties. These results provide the basis for a synthetic strategy for increasing the HER electrocatalytic activity of MoS2 by tuning its crystal properties, and thus improving its potential for use in hydrogen production technologies. Copyright
- Lau, Vincent Wing-Hei,Masters, Anthony F.,Bond, Alan M.,Maschmeyer, Thomas
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experimental part
p. 8230 - 8239
(2012/08/29)
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- A convenient synthesis of triflate anion ionic liquids and their properties
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A solvent- and halogen-free synthesis of high purity triflate ionic liquids via direct alkylation of organic bases (amines, phosphines or heterocyclic compounds) with methyl and ethyl trifluoromethanesulfonate (methyl and ethyl triflate) has been developed. Cheap and non-toxic dimethyl and diethyl carbonate serve as source for the methyl and ethyl groups in the preparation of methyl and ethyl triflate by this invented process. The properties of ionic liquids containing the triflate anion are determined and discussed.
- Ignat'ev, Nikolai V.,Barthen, Peter,Kucheryna, Andryi,Willner, Helge,Sartori, Peter
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experimental part
p. 5319 - 5338
(2012/08/28)
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- Arylation of sensitive 1-(Pyrrolidin-1-yl)-diazen-1-ium-diolate in ionic liquids
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The purpose of this research was to investigate the stability and reactivity of 1-(pyrrolidin-1-yl)diazen-1-ium-1,2-diolate (PYRRO/NO) in dimethylformamide (DMF, as the reference solvent) and compare them to those obtained using different ionic liquids. The results of our experiments showed that PYRRO/NO is more stable (based on reactivity) in ionic liquid [EMIM][Ms] (with reaction yields up to 52%) than in DMF, that substitution products can be separated directly and quantitatively from the ionic liquid using a single flash-column separation, and that the ionic liquids can also be recovered and reused in a second iteration of the same reaction to achieve similar yields.
- Velazquez, Carlos A.,Lynn, Geoffrey M.,Kumar, Vineet,Keefer, Larry K.,Malhotra, Sanjay V.
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experimental part
p. 1322 - 1332
(2010/07/04)
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- Synthesis of imidazolium and pyridinium-based ionic liquids and application of 1-alkyl-3-methylimidazolium salts as pre-catalysts for the benzoin condensation using solvent-free and microwave activation
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An efficient one-pot procedure for the synthesis of ionic liquids based on nitrogen-containing heterocycles, imidazolium or pyridinium under 'green chemistry' conditions has been described. Imidazolium salts and DBU have been found to catalyze efficiently the benzoin condensation giving good yields within very short reaction time using solvent-free microwave activation conditions.
- Aupoix, Audrey,Pégot, Bruce,Vo-Thanh, Giang
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scheme or table
p. 1352 - 1356
(2010/04/02)
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- Mild oxidative conversion of nitroalkanes into carbonyl compounds in ionic liquids
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Basic hydrogen peroxide and sodium perborate were found to be cheap and efficient alternatives for the conversion of primary and secondary nitro to carbonyl compounds (Nef reaction) in ionic liquids. Copyright Taylor & Francis Group, LLC.
- Bortolini, Olga,Nino, Antonio De,Garofalo, Angelo,Maiuolo, Loredana,Russo, Beatrice
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experimental part
p. 2483 - 2487
(2010/09/07)
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- Erbium triflate in ionic liquids: A recyclable system of improving selectivity in Diels-Alder reactions
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The efficiency of Er(OTf)3 in promoting the Diels-Alder reactions between different dienes and dienophiles in ionic liquids has been investigated. Compared with the analogous cycloadditions performed in conventional solvents shorter reaction times are required to obtain good/excellent yields. In most cases an enhancement of regio- and endo:exo selectivity was observed. The role of the ionic liquid, as a function of the cationic part, i.e. the imidazolium based or the pyridinium based, is discussed well. The ILs containing the catalyst can be readily separated from the reaction products and recovered in very high purity for direct reuse, up to six cycles.
- Bortolini, Olga,De Nino, Antonio,Garofalo, Angelo,Maiuolo, Loredana,Procopio, Antonio,Russo, Beatrice
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experimental part
p. 124 - 129
(2011/02/16)
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- Imidazolium ionic liquids: A simple anion exchange protocol
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An efficient and simple protocol was developed to obtain quantitative iodide or bromide exchange for a broad range of anions in imidazolium ionic liquids. Selected anions were loaded in an anion exchange resin using two different procedures and were then used to provide a pure convenient ion pair. The Royal Society of Chemistry 2009.
- Dinares, Immaculada,Garcia De Miguel, Cristina,Ibanez, Anna,Mesquida, Neus,Alcalde, Ermitas
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supporting information; experimental part
p. 1507 - 1510
(2010/06/11)
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- Efficient intramolecular hydroalkoxylation/cyclization of unactivated alkenols mediated by lanthanide triflate ionic liquids
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Lanthanide triflates, Ln(OTf)3, serve as efficient catalysts for the intramolecular hydroalkoxylation (HO)/cyclization of primary/secondary and aliphatic/aromatic hydroxyalkenes in room temperature ionic liquids (RTlLs). Cyclizations are effective in the formation of five-and sixmembered oxygen heterocycles with Markovnikov-type selectivity. Reaction rates exhibit first-order dependence on [Ln3+] and [substrate].
- Dzudza, Alma,Marks, Tobin J.
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supporting information; experimental part
p. 1523 - 1526
(2009/09/06)
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- Preparation of second generation ionic liquids by efficient solvent-free alkylation of N-heterocycles with chloroalkanes
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Non-conventional techniques, such as microwave (MW) and power ultrasound (US) as well as combined MW/US irradiation, have been used to promote one-pot synthesis of second-generation ionic liquids (ILs), cutting down reaction times and improving yields. However, the use of chloroalkanes in the alkylation of N-heterocycles requires more drastic conditions if results are to match those obtained with more reactive alkyl halides. The present paper describes a series of MW- or MW/US-promoted IL preparations starting from chloroalkanes and classic heterocycles (1-methylimidazole, pyridine and 1-methylpyrrolidine). When reactions were carried out under conventional heating in an oil bath they required longer reaction times and gave poorer yields. 1H-NMR analysis and ion-exchange chromatography showed that the present solventless procedure afforded ILs of satisfactory purity. The observed high yields (usually 70-98% isolated), and short reaction times showed that a straightforward access to ILs can be also achieved with the use of alkyl chlorides, resulting in a considerable reduction of costs.
- Cravotto, Giancarlo,Gaudino, Emanuela Calcio,Boffa, Luisa,Leveque, Jean-Marc,Estager, Julien,Bonrath, Werner
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p. 149 - 156
(2008/09/17)
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- Method of preparation of halogen-free ionic liquids and ionic liquids prepared in this manner
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The reaction of N-alkylimidazol with alkyl sulfonates, at room temperature, favors the production of 1,3-dialkylimidazolium alkane-sulfonates as crystalline solids at high yields. The alkane-sulfonate anions may be easily substituted by a series of other anions [BF4, PF6, PF3(CF2CF3)3, CF3SO3 and (CF3SO2)2N] through simple anion, salt, or acid reactions in water at room temperature. The extraction with dichloromethane, filtration, and evaporation of the solvent, allows the production of the desired ionic liquids at a yield of 80-95%. The purity of these ionic liquids (in some cases >99.4%) is performed using the intensity of 13C satellite signals from the magnetic resonance spectrums of the N-methyl imidazolium group as an internal standard.
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Page/Page column 4
(2008/06/13)
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- A rationalization of the solvent effect on the Diels-Alder reaction in ionic liquids using multiparameter linear solvation energy relationships
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The Diels-Alder reaction between cyclopentadiene and three dienophiles (acrolein, methyl acrylate and acrylonitrile) having different hydrogen bond acceptor abilities has been carried out in several ionic liquids and molecular solvents in order to obtain information about the factors affecting reactivity and selectivity. The solvent effects on these reactions are examined using multiparameter linear solvation energy relationships. The collected data provide evidence that the solvent effects are a function of both the solvent and the solute. For a solvent effect to be seen, the solute must have a complimentary character; selectivities and rates are determined by the solvent hydrogen bond donation ability (α) in the reactions of acrolein and methyl acrylate, but not of acrylonitrile. The Royal Society of Chemistry 2008.
- Bini, Riccardo,Chiappe, Cinzia,Mestre, Veronica Llopsis,Pomelli, Christian Silvio,Welton, Thomas
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supporting information; experimental part
p. 2522 - 2529
(2009/02/02)
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- Improved activity of horseradish peroxidase (HRP) in 'specifically designed' ionic liquid
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The ionic liquid (IL), tetrakis (2-hydroxyethyl) ammonium triflouromethanesulfonate is rationally designed for horseradish peroxidase (HRP) on the basis of its stability and activity in the presence of an excipient, tris(hydroxymethyl)aminoethane (TRIS) in different ILs. The activity of HRP in this tailor made IL is at least 30-240-fold higher than that in conventional ILs. Also, the activity is more than 10 times greater than that in methanol, a common organic solvent used for HRP.
- Das, Dibyendu,Dasgupta, Antara,Das, Prasanta Kumar
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p. 5635 - 5639
(2008/03/11)
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- A speedy one-pot synthesis of second-generation ionic liquids under ultrasound and/or microwave irradiation
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The present work describes an efficient one-pot synthesis of second-generation ionic liquids (ILs), combining in one step the Menshutkin reaction and anion metathesis. Working in a closed vessel under microwaves, or better still under simultaneous ultrasound and/or microwave irradiation, in a few minutes a series of ILs with 1-methylimidazole or pyridine cores were obtained in high yields (80?97% isolated). Under conventional heating, ILs could not be prepared in one pot in acceptable times and yields, whereas our protocol, carried out with commercially available equipment, was highly effective and reproducible. Moreover, 1H NMR analysis and ion-exchange chromatography showed that the present solventless procedure afforded satisfyingly pure ILs. CSIRO 2007.
- Cravotto, Giancarlo,Boffa, Luisa,L'Eveque, Jean-Marc,Estager, Julien,Draye, Micheline,Bonrath, Werner
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p. 946 - 950
(2008/03/17)
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- One-pot and solventless synthesis of ionic liquids under ultrasonic irradiation
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A novel method is described for the one-pot synthesis of various ionic liquids in a competitive time. By using ultrasonic irradiation, different families of nitrogen-bearing ionic liquids can be obtained in a solvent-free or in aqueous medium, which gives a greener touch to the overall process. Georg Thieme Verlag Stuttgart.
- Estager, Julien,Lévêque, Jean-Marc,Cravotto, Giancarlo,Boffa, Luisa,Bonrath, Werner,Draye, Micheline
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p. 2065 - 2068
(2008/02/10)
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- METHOD FOR PRODUCING ONIUM SALTS COMPRISING ALKYL ANIONS OR ARYL SULFONATE ANIONS OR ALKYL ANIONS OR ARYL CARBOXYLATE ANIONS HAVING A LOW HALIDE CONTENT
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The invention relates to a method for producing onium salts comprising alkyl anions or aryl sulfonate anions or alkyl carboxylate anions or acryl carboxylate anions by reacting an onium halide with an alkyl silyl ester or trialkyl silyl ester of an alkyl sulfonic acid or aryl sulfonic acid or an alkyl carboxylic acid or aryl carboxylic acid or the anhydrides thereof.
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Page/Page column 27
(2008/06/13)
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- METHOD FOR PRODUCING ONIUM SALTS WITH A LOW CHLORIDE CONTENT
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The invention relates to a method for producing onium salts with a low chloride content by reacting an onium chloride with an acid. According to the invention, the hydrochloric acid that is produced can be removed by co-ordination with an organic solvent, which forms an azeotropic mixture with water, and by subsequent azeotropic distillation.
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Page/Page column 23-24
(2008/06/13)
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- Melting point depression of ionic liquids confined in nanospaces
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A new physical method was proposed to control the liquid properties of room temperature ionic liquids (RT-ILs) in combination with nanoporous materials; the melting point of ILs confined in nanopores remarkably decreases in proportion to the inverse of the pore size. The Royal Society of Chemistry 2006.
- Kanakubo, Mitsuhiro,Hiejima, Yusuke,Minami, Kimitaka,Aizawa, Takafumi,Nanjo, Hiroshi
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p. 1828 - 1830
(2008/03/13)
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- A PURIFICATION METHOD OF IONIC LIQUIDS TO OBTAIN THEIR HIGH PURITY
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Disclosed is an ionic liquid purification method for preparing high purity ionic liquids which can be used as solvents for organic, inorganic and biochemical reactions or as electrolytic solutions of storage batteries, secondary batteries, or fuel batteries, by removing organic halide salts, organic salts, halide residues, acid residues, excess alkali metals and so on, from unpurified ionic liquids using liquid/liquid continuous extraction.
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- Physicochemical properties and structures of room temperature ionic liquids. 1. Variation of anionic species
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Room-temperature ionic liquids (RTILs) based on 1-butyl-3-methylimidazolium ([bmim]) with a variety of fluorinated anions were prepared, and the thermal behavior, density, viscosity, self-diffusion coefficients of the cations and anions, and ionic conductivity were measured over a wide temperature range. The temperature dependencies of the self-diffusion coefficient, viscosity, ionic conductivity, and molar conductivity have been fitted to the Vogel-Fulcher-Tamman equation, and the best-fit parameters for the self-diffusion coefficient, viscosity, ionic conductivity, and molar conductivity have been estimated, together with the linear fitting parameters for the density. The self-diffusion coefficients determined for the individual ions by pulsed-field-gradient spin-echo NMR method exhibit higher values for the cation compared with the anion over a wide temperature range, even if its radius is larger than that of the anionic radii. The summation of the cationic and anionic diffusion coefficients for the RTILs follows the order [bmim][(CF3SO2N] > [bmim][CF 3CO2] > [bmim][CF3SO3] > [bmim][BF4] > [bmim][(C2F5SO 2)2N] > [bmim][PF6] at 30?°C, and the order of the diffusion coefficients greatly contrasts to the viscosity data. The ionic association is proposed from the results of the ratios of molar conductivity obtained from impedance measurements to that calculated by the ionic diffusivity using the Nernst-Einstein equation. The ratio for the ionic liquids follows the order [bmim][PF6] > [bmim][BF4] > [bmim][(C2F5SO2)2N] > [bmim][(CF3SO2)2N] > [bmim][CF 3SO3] > [bmim][CF3CO2] at 30?°C and provides quantitative information on the active ions contributing to ionic conduction in the diffusion components.
- Tokuda, Hiroyuki,Hayamizu, Kikuko,Ishii, Kunikazu,Susan, Md. Abu Bin Hasan,Watanabe, Masayoshi
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p. 16593 - 16600
(2007/10/03)
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- Liquid Phase Behavior of Imidazolium-Based Ionic Liquids with Alcohols
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A systematic study of the impact of different characteristics of the ionic liquids (IL) and the alcohols on the liquid-liquid phase equilibrium of imidazolium-based IL and alcohols. Alcohol characteristics investigated include the effect of increasing the alkyl chain length of the alcohol (1-propanol vs. 1-butanol or 1-hexanol) and the effect of branching of the alcohol (1-butanol vs. 2-butanol or tert-butyl alcohol). An increase in the alkyl chain length of the alcohol resulted in an increase in the upper critical solution temperature (UCST), since the alcohol became more aliphatic and less able to interact with the IL through hydrogen-bonding, dipolar, and Coulombic forces. Increased branching of the alcohol did not affect the UCST but resulted in an increase in the solubility of the alcohol in the IL-rich phase, which correlates with increasing basicity of the alcohols. An increase in the length of one of the alkyl chains on the cation resulted in a decrease in the UCST, likely due to greater dispersion interactions between the alkyl chain on the cation and the chain of the alcohol. The UCST of the IL with alcohols decreased with increasing hydrogen bond strength. The effect of alkyl chain length on the cation and the choice of anion had significantly different effects on the mutual solubilities of IL with water than with alcohols.
- Crosthwaite, Jacob M.,Aki, Sudhir N. V. K.,Maginn, Edward J.,Brennecke, Joan F.
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p. 5113 - 5119
(2007/10/03)
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- Solvent-solute interactions in ionic liquids
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A range of ionic liquids was studied utilizing the Kamlet-Taft parameters hydrogen bond acidity (α), hydrogen bond basicity (β), and dipolarity/polarizability effects (π*). Some of the ionic liquids studied were methanol, acetonitrile, acetone, dichloromethane, toluene, hexane, and water. π* was high for all the ionic liquids investigated and varied with both anion and cation. α was generally moderate and depended chiefly on the cation. β was also moderate and depended mainly on the anion. Comparison was made with other polarity measurements in ionic liquids.
- Crowhurst, Lorna,Mawdsley, Philip R.,Perez-Arlandis, Juan M.,Salter, Paul A.,Welton, Tom
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p. 2790 - 2794
(2007/10/03)
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- Ionic liquids of chelated orthoborates as model ionic glassformers
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Ionic liquids based on various chelated orthoborate anions of different N-containing onium cations have been synthesized using an economic synthesis strategy. Most orthoborates do not crystallize. They are found to have much higher glass transition temperatures and room-temperature viscosities than those with perfluorinated anions such as TFSI-, BF4-, and CF3SO3- (Tf-), as predicted from anion polarizability arguments. The ambient conductivities of the new ionic liquids are low relative to those with perfluorinated anions. The transport properties all show that cohesion in these liquids increases, and ionic mobilities decrease, as anion size increases, implying that van der Waals interactions, not Coulomb interactions, have become the controlling influence. In view of their resistance to crystallization, the large range of temperature over which these liquids can be studied, their hydrophobic properties, and their high fragilities, these liquids may provide good model systems for fundamental liquid state investigations and interesting solvents for large-molecule dissolution.
- Xu, Wu,Wang, Li-Min,Nieman, Ronald A.,Angell, C. Austen
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p. 11749 - 11756
(2007/10/03)
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- Halogenide-free preparation of ionic fluids
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Preparation of ionic liquids (I) involves alkylating an amine, phosphine, imidazole, pyridine, triazole or pyrazole corresponding to the cation of (I) with a sulfate diester (II), then replacing the sulfate anion by the anion of (I). Preparation of ionic liquids of formula (I) involves alkylating the amine, phosphine, imidazole, pyridine, triazole or pyrazole, corresponding to the cation A, with a sulfate diester of formula (II), then replacing the sulfate anion R4SO4 or R5SO4 by the anion Yn-. (An).(Yn-) (I) R4SO2R5 (II) n = 1 or 2; Yn- = BF4, BCl4, PF6, SbF6, AsF6, AlCl4, ZnCl3, CuCl2, SO4, CO3, R'COO, R'SO3 or (R'SO2)2N; R' = 1-12C linear, branched or cyclic alkyl, 5-18C aryl, (5-18C) aryl-(1-6C) alkyl or (1-6C) alkyl-(5-18C) aryl (all optionally halo-substituted); A = NR1R2R3R or PR1R2R3R; or 1-(R)-3-(R1)-imidazolium, (R1)-substituted 1-(R)-pyridinium, 1-(R)-2-(R1)-pyrazolium or 1-(R)-1,3,5-triazolium (all optionally ring-substituted by one or more of 1-6C alkyl, 1-6C alkoxy, 1-6C aminoalkyl, 5-12C aryl or (5-12C) aryl-(1-6C) alkyl); R1-R3 = H; 1-20C linear, branched or cyclic alkyl; Het or Het-(1-6C) alkyl; or Ar or Ar-(1-6C) alkyl; R, R4, R5 = 1-24C linear, branched or cyclic alkyl; Het-(1-6C) alkyl; or Ar'-(1-6C) alkyl; Het = heteroaryl containing 3-8C and at least one of N, O and S (optionally substituted by one or more of 1-6C alkyl and halo); Ar = 5-12C aryl (optionally substituted by one or more of 1-6C alkyl and halo); and Ar' = 5-24C aryl (optionally substituted by one or more of 1-6C alkyl and halo).
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