Ammonium Ionic Liquids Research Articles

Surface tension of binary mixtures of imidazolium and ammonium based ionic liquids with alcohols, or water: Cation, anion effect

The surface tensions were measured at atmospheric pressure, with use of a ring tensiometer, of a series of alcoholic solutions of closely related ionic liquids: 1-methyl-3-methylimidazolium methylsulfate, [MMIM][CH 3SO 4] in alcohol (methanol, or ethanol, or 1-butanol at 298.15 K), 1-butyl-3-methylimidazolium methylsulfate, [BMIM][CH 3SO 4] in alcohol (methanol, or ethanol, or 1-butanol at 298.15 K), 1-butyl-3-methylimidazolium octylsulfate, [BMIM][OcSO 4] in alcohol (methanol, or 1-butanol at 298.15 K) and of 1-hexyloxymethyl-3-methylimidazolium tetrafluoroborate, [C 6H 13OCH 2MIM][BF 4], 1,3-dihexyloxymethylimidazolium tetrafluoroborate, [(C 6H 13OCH 2) 2IM][BF 4] in alcohol (methanol, or 1-butanol, or 1-hexanol at 308.15 and 318.5 K) and hexyl(2-hydroxyethyl)dimethylammonium bromide, C 6Br in 1-octanol at 298.15 K. The set of ammonium ionic liquids of different cations and anions (C 2Br, C 2BF 4, C 2PF 6, C 2N(CN) 2, C 3Br, C 4Br and C 6Br) was chosen to show the influence of small amount of the ammonium ionic liquid on the surface tension of water at 298.15 K. The influence of the cation, or anion alkyl chain length on the properties under study (densities and surface tension) was tested.

A Lithium Battery Electrolyte Based on a Room-temperature Phosphonium Ionic Liquid

Abstract The electrolytic properties of a lithium battery electrolyte based on triethyl(2-methoxyethyl)phosphonium bis(trifluoromethylsulfonyl)imide are described. Testing charge–discharge performance of the cell containing the lithium-binary phosphonium ionic liquid electrolyte showed excellent capacity and rechargeability, compared to the cell containing a comparative ammonium ionic liquid electrolyte.

ChemInform Abstract: Synthesis of Metal‐Free Phthalocyanines in Functionalized Ammonium Ionic Liquids.

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Solubility of fluorinated compounds in a range of ionic liquids. Cloud-point temperature dependence on composition and pressure

In this work, we explore the mutual solubility of a number of mixtures of commonly used ionic liquids (imidazolium, pyridinium, phosphonium and ammonium ionic liquids) with partially fluorinated n-alcohols (C7 to C10) or perfluoroheptane. The corresponding T–x diagrams at atmospheric pressure were measured through cloud-point temperature determinations. For some selected systems under near-critical isopleth conditions, pressure effects were also studied. The results are discussed in terms of (i) shifts in the immiscibility envelopes as the cation alkyl-chain length is changed, (ii) the nature of the cation or the anion, (iii) the increasing length of the fluorinated/alkylic moiety of the partially fluorinated alcohol, or (iv) comparisons with similar systems involving normal alcohols.

Electrochemical Behavior of Lithium in Room-Temperature Phosphonium Ionic Liquids as Lithium Battery Electrolytes

Electrochemical deposition and dissolution of metallic lithium in various phosphonium ionic liquids with bis(trifluoromethylsulfonyl)imide anion were evaluated by cyclic voltammetry using a Ni electrode. In the voltammograms measured in phosphonium ionic liquids containing 0.8 mol dm -3 lithium cation, cathodic and anodic peaks attributed to the deposition and dissolution of metallic lithium were observed at approximately -3.1 V vs Fc/Fc + . It was also found that phosphonium ionic liquids tended to give larger redox responses for the lithium deposition/dissolution than those of the corresponding ammonium ionic liquids.

Phase Equilibria and Modeling of Ammonium Ionic Liquid, C2NTf2, Solutions

Novel quaternary ammonium ionic liquid, ethyl(2-hydroxyethyl)dimethylammonium bis(trifluomethylsulfonyl)imide (C2NTf2), has been prepared from N,N-dimethylethanolamine as a substrate. The paper includes a specific basic characterization of the synthesized compound by NMR and the basic thermophysical properties: the melting point, enthalpy of fusion, enthalpy of solid-solid phase transition, glass transition determined by the differential scanning calorimetry (DSC), temperature of decomposition, and water content. The density of the new compound was measured. The solid-liquid or liquid-liquid phase equilibria of binary mixtures containing {C2NTf2+water or an alcohol (propan-1-ol, butan-1-ol, hexan-1-ol, octan-1-ol, decan-1-ol), aromatic hydrocarbons (benzene, toluene), aliphatic hydrocarbons (n-hexane, n-octane), dimethylsulfoxide (DMSO), or tetrahydrofuran (THF)} have been measured by a dynamic method in a wide range of temperatures from 230 to 430 K. These data were correlated by means of the nonrandom two-liquid (NRTL) equation utilizing temperature-dependent parameters derived from the solid-liquid or liquid-liquid equilibrium. From the solubility results, the negative value of the partition coefficient of ionic liquid in binary system octan-1-ol/water (log P) at 298.15 K has been calculated.

Dye-Sensitized Solar Cells Based on Quaternary Phosphonium Ionic Liquids as Electrolytes

Abstract Dye-sensitized solar cells using quaternary phosphonium ionic liquids as their electrolytes have been successfully fabricated. Of these, the best device performance was achieved by using triethyl(pentyl)phosphonium bis(trifluoromethylsulfonyl)amide, whose energy conversion efficiencies were determined to be 1.2% and 3.8% under full (AM 1.5, 100 mW cm−2) and low intensity (7 mW cm−2) sunlight illumination, respectively. Interestingly, the energy conversion efficiencies for the quaternary phosphonium ionic liquid electrolytes are higher than those for the corresponding quaternary ammonium ionic liquids.

Efficient Synthesis of Transition-Metal Phthalocyanines in Functional Ionic Liquids

The synthesis of transition-metal phthalocyanines by the reaction of substituted and unsubstituted phthalonitriles in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and metal salts in functional imidazolium, pyridinium and ammonium ionic liquids at 100-140 °C, is reported. The best yields of metallated phthalocyanines were achieved in butyl(2-hydroxyethyl)dimethylammonium bromide ionic liquid. Metallation of free-base phthalocyanines with different metal salts in the above ionic liquid has also been achieved in good yields.

Liquid Phase Behavior of Ionic Liquids with Water and 1-Octanol and Modeling of 1-Octanol/Water Partition Coefficients

This study examines the effect of structural components of an ionic liquid (IL), including the choice of the anion, alkyl chain length on the cation, and substitution on the cation, on the mutual solubility with water and with 1-octanol. This is important because ionic liquids have been shown to be good replacements for organic extraction solvents in some liquid separations. In addition, we use the measured data to predict 1-octanol/water partition coefficients for the ionic liquids using the nonrandom two liquid (NRTL) and electrolyte nonrandom two liquid (eNRTL) excess Gibbs energy models. Specifically, the mutual solubilities of 15 different imidazolium, pyridinium, and quaternary ammonium ionic liquids with water were measured at (23.5 ± 1) °C. An increase in the alkyl chain length or the substitution decreases the mutual solubility with water. The [BF4]- and [B(CN)4]- anions are significantly more hydrophilic than [PF6]-, [(CF3SO2)2N]-, and [(CF3SO2)3C]-. The mutual solubilities of 10 ILs with 1-octa...

A Comparative Study on Absorption and Selectivity of Organic Vapors by Using Ionic Liquids Based on Imidazolium, Quaternary Ammonium, and Guanidinium Cations

A novel study on organic solute absorption from the vapor phase is reported. The organic solutes chosen for the absorption studies include 1,4-benzodioxane, biphenyl, xanthene, and menthol. A series of imidazolium, ammonium, and guanidinium-based ionic liquids (ILs) containing several types of anions were used as absorbents. Absorption of water vapor was also studied along with the organic solutes. Absorption studies of each organic solute were performed by using a specially devised glass apparatus at 50 degrees C. It was observed that the rate of absorption increases with time and is faster in the case of 1,4-benzodioxane (24 h). The absorption process for each organic solute with different classes of ionic liquids was studied and the results were compared with each other. Absorption values of more than 25,000 ppm were observed in some ionic liquids. Distribution ratios of organic solutes in an ionic liquid and in the vapor phase were measured and the selectivity was evaluated by using the distribution ratio values. A remarkable selectivity was observed for some ionic liquids towards a specific organic solute. Importantly, it was observed that the selectivity remained constant, even though a mixture of solute was used for the absorption study. Desorption of organic vapors from ionic liquids was successfully carried out by applying a vacuum. Further, it was observed that the same ionic liquid can be repeatedly reused several times for absorption. These studies reveal that, in future, a task-specific ionic liquid can be prepared and used for specific solute capture from the vapor phase.

Thermodynamic Phase Behavior of Ionic Liquids

The phase diagrams of the following imidazolium ionic liquids, {1-ethyl-3-methylimidazolium tosylate [EMIM][TOS] + hexane or cycloheptane} and {1-ethyl-3-methylimidazolium ethylsulfate [EMIM][EtSO4] + hexane or benzene}, have been measured. The (solid + liquid) (SLE) and (liquid + liquid) (LLE) phase equilibria of binary mixtures containing {hexyl(2-hydroxyethyl)dimethylammonium bromide (C6Br) + hexane or benzene or an alcohol (ethanol or dodecan-1-ol)} and the salt with a different anion {hexyl(2-hydroxyethyl)dimethylammonium tetrafluoroborate (C6BF4) + hexane or benzene or dodecan-1-ol} have been measured. The effect of anion type (Br- vs BF4-) on the thermophysical properties of the IL and on the phase behavior is dependent on the strength of the cation−anion interaction in the investigated ILs and is noticeable. The phase diagrams for some novel ammonium ionic liquids, (2-decanoyloxyethyl)dimethylpentyloxymethylammonium trifluoro-acetate [C10OOEtC5OMMMN][CF3COO] or (2-methyloyoxyethyl)dimethylpentylox...

Synthesis of Metal‐Free Phthalocyanines in Functionalized Ammonium Ionic Liquids

A convenient, fast, efficient, and ecofriendly synthesis of metal‐free phthalocyanines from various substituted phthalonitriles in different hydroxyalkylammonium ionic liquids in the presence of 1,8‐diazabicyclo‐[5,4,0]‐undec‐7‐ene (DBU) is reported in moderate yields. The effect of concentration of DBU and temperature on the synthesis of phthalocyanine in N‐(2‐hydroxyethyl)‐N,N‐dimethylbutylammonium bromide ionic liquid has been examined, and the ionic liquid has been recovered and reused conveniently.

Physical and electrochemical properties of low-viscosity phosphonium ionic liquids as potential electrolytes

A new group of room temperature ionic liquids based on triethylalkylphosphonium cations together with a bis(trifluoromethylsulfonyl)imide anion as a novel electrolyte is presented in this report. It was found that phosphonium ionic liquids showed lower viscosities and higher conductivities than those of the corresponding ammonium ionic liquids. Particularly, phosphonium ionic liquids containing a methoxy group, triethyl(methoxymethyl)phosphonium bis(trifluoromethylsulfonyl)imide and triethyl(2-methoxyethyl)phosphonium bis(trifluoromethylsulfonyl)imide, exhibited quite low viscosities (35 and 44 mPa s at 25 °C, respectively). Linear sweep voltammetry measured in neat phosphonium ionic liquids at a glassy carbon electrode indicated wide potential windows (at least −3.0 to +2.3 V vs. Fc/Fc +). Thermogravimetric analysis suggested that phosphonium ionic liquids were thermally stable up to nearly 400 °C, showing slower gravimetric decreases at high temperature compared to those of the corresponding ammonium ionic liquids.

Separation of aromatic hydrocarbons from alkanes using ammonium ionic liquid C 2NTf 2 at T = 298.15 K

(Liquid + liquid) equilibrium data are presented for four ternary systems of an alkane, or aromatic compound and ethyl(2-hydroxyethyl)dimethylammonium bis{(trifluomethyl)sulfonyl}imide (C 2NTf 2) at 298.15 K: [hexane + benzene + C 2NTf 2], [hexane + p-xylene + C 2NTf 2], and [hexane, or octane + m-xylene + C 2NTf 2]. The separation of aromatic hydrocarbons (benzene, or p-xylene, or m-xylene) from aliphatic hydrocarbons (hexane, or octane) is investigated by extraction with the ammonium ionic liquid. Selectivities and distribution ratios are discussed for these mixtures at constant temperature. The data were analysed and compared to those previously reported for other ionic liquids and especially for the system {hexane + benzene + [EMIM][NTf 2]}. The nonrandom two liquid NRTL model was successfully used to correlate the experimental tie-lines and to calculate the phase compositions of the ternary systems. The data presented indicate the suitability of C 2NTf 2 as a good solvent for the separation of aromatic and aliphatic hydrocarbons using solvent extraction.

Ammonium ionic liquid as modulator of the critical micelle concentration of ammonium surfactant at aqueous solution: Conductimetric and dynamic light scattering (DLS) studies

We report measurements of self aggregation in aqueous solution of an ionic liquid (IL), didecyl-dimethylammonium nitrate ([DDA][NO 3]) and a surfactant hexadecyl-trimethylammonium bromide (CTAB) and of mixtures of these two salts. The electrical conductivity and dynamic light scattering (DLS) measurements were used for the characterization of the aggregation process. The conductivity measurements were performed at three temperatures. The critical micelle concentration (CMC) was determined at different temperatures and at different ratio of two salts. The effect of IL on the micellization of CTAB has been discussed. Our results suggest that organized structures formed by CTAB and [DDA][NO 3] self assembly in domains of several hundred nanometers size. The micellar solubility of the salicylic acid in mixed salt aqueous solutions was determined to probe the physical properties of these assemblies. We have observed, that the micellar solubility enhancement was only slightly influenced by the nature of micelles present in aqueous solution. This proves that salicylic acid solubilization is enthalpy driven.

Hydroxyl Ammonium Ionic Liquids: Synthesis, Properties, and Solubility of SO2.

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Investigation of Ether-Substituted Quaternary Ammonium Ionic Liquids

The effect of structural rigidity in quaternary ammonium-based ionic liquids (ILs) was investigated. and , both 8 atom (7 carbons, 1 oxygen) ether-substituted quaternary ammonium chlorides (Quats), were syn thesized and investigated. In acetonitrile, placement of the oxygen one atom from the nitrogen (Quat I) resulted in a significant decrease in the reductive stability. While the IL form showed similar stability for the two systems, placing the oxygen close to the nitrogen (methyl ethyl ether) appears to localize a greater portion of the positive charge on the nitrogen. This results in an IL with a higher melting point than the nonether analog, (III, ) IL. In contrast, placing two carbon atoms between the nitrogen and ether group, ethyl methyl ether (Quat II), delocalizes the positive charge from the nitrogen and produces a room-temperature IL. Neutralization of the acidic IL with sodium chloride resulted in an increase in the bulk conductivity, due to the polar ether group. Upon addition of or , which both form a solid-electrolyte interphase on the substrate surface, the increased free sodium ion concentration allowed sodium reduction and oxidation currents greater than at room temperature.

Preparation of Dialkoxypropanes in Simple Ammonium Ionic Liquids.

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Hydroxyl Ammonium Ionic Liquids: Synthesis, Properties, and Solubility of SO2

To explore environmentally benign solvents for absorbing SO2, a series of hydroxyl ammonium ionic liquids (ILs) was synthesized and characterized, and the solubilities of SO2 in these synthesized ILs were determined. It was found that the solubilities of SO2 in these ILs at ambient pressure are quite high, for example, the solubility of SO2 in tri-(2-hydroxyethyl)ammonium lactate is 0.4957 mole fraction and decreases sharply as temperature increase. The absorption and desorption are practically reversible in the synthesized ILs. Comparing with the conventional absorbents such as calcium carbonate (CaCO3), calcium oxide (CaO), and sodium hydroxide (NaOH), the synthesized ILs show two advantages: one is that the ILs can be recycled and repeatedly used, another is that the absorbed SO2 can be reversibly released and recovered as a sulfur resource.

Solubilities of CO 2 in hydroxyl ammonium ionic liquids at elevated pressures

Solubilities of CO 2 in eight hydroxyl ammonium ionic liquids 2-hydroxy ethylammonium formate (HEF), 2-hydroxy ethylammonium acetate (HEA), 2-hydroxy ethylammonium lactate (HEL), tri-(2-hydroxy ethyl)-ammonium acetate (THEAA), tri-(2-hydroxy ethyl)-ammonium lactate (THEAL), 2-(2-hydroxy ethoxy)-ammonium formate (HEAF), 2-(2-hydroxy ethoxy)-ammonium acetate (HEAA) and 2-(2-hydroxy ethoxy)-ammonium lactate (HEAL) at the temperatures ranging from 303 to 323 K and the pressures ranging from 0 to 11 MPa were determined. The solubility data were correlated using Krichevisky–Kasarnovsky equation, from which Henry's constants and the partial volumes of CO 2 at different temperature were obtained. Results showed that Krichevsky–Kasarnovsky equation can correlate the solubilities of CO 2 in these hydroxyl ammonium ionic liquids (ILs) well. Comparison showed that the solubility of CO 2 in these eight hydroxyl ammonium ionic liquids was in sequence: THEAL > HEAA > HEA > HEF > HEAL > THEAA ≈ HEL > HEAF.