POSS-Tetraalkylammonium Salts: A New Class of Ionic Liquids (original) (raw)
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Star-Shaped Quaternary Alkylammonium Polyhedral Oligomeric Silsesquioxane Ionic Liquids
European Journal of Inorganic Chemistry, 2014
New star-shaped quaternary ammonium (QA) polyhedral oligomeric silsesquioxane (POSS) salts based on octakis-(tetraalkylammonium) POSS cations bearing alkyl chains of different length (methyl, n-butyl, and n-octyl) and differently polarizable anions [iodide, bis(trifluoromethylsulfonyl)imide, and ibuprofen] have been synthesized and characterized. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) investigations show that the nature of the cation plays a key role in determining the thermal behavior of QA POSS salts featuring the longest alkyl chains, whereas
Tetraalkylphosphonium Polyoxometalate Ionic Liquids: Novel, Organic−Inorganic Hybrid Materials
The Journal of Physical Chemistry B, 2007
Pairing of a Keggin or Lindqvist polyoxometalate (POM) anion with an appropriate tetraalkylphosphonium cation is shown to yield the first members of a new family of ionic liquids (ILs). Detailed characterization of one of them, an ambient-temperature "liquid POM" comprising the Lindqvist salt of the trihexyl(tetradecyl) phosphonium cation, by voltammetry, viscometry, conductimetry, and thermal analysis indicates that it exhibits conductivity and viscosity comparable to those of the one previously described inorganic-organic POM-IL hybrid but with substantially improved thermal stability.
Acs Applied Materials & Interfaces, 2009
A new type of supported liquid membrane was made by combining an ionic liquid (IL) with a Nafion membrane reinforced with multifunctional polyhedral oligomeric silsesquioxanes (POSSs) using a layer-by-layer strategy for anhydrous proton-exchange membrane (PEM) application. The POSS was functionalized by direct sulfonation, and the sulfonated POSS (S-POSS) was incorporated into Nafion 117 membranes by the infiltration method. The resultant hybrid membrane shows strong ionic interaction between the Nafion matrix and the multifunctional POSS, resulting in increased glass transition temperature and thermal stability at very low loadings of S-POSS (1%). The presence of S-POSS has also improved the proton conductivity especially at low humidities, where it shows a marked increase due to its confinement in the ionic domains and promotes water uptake by capillary condensation. In order to achieve anhydrous conductivity, the IL 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMI-BTSI) was incorporated into these membranes to provide proton conduction in the absence of water. Although the incorporation of an IL shows a plasticizing effect on the Nafion membrane, the S-POSS composite membrane with an IL shows a higher modulus at high temperatures compared to Nafion 117 and a Nafion-IL membrane, with significantly higher proton conductivity (5 mS/cm at 150°C with 20% IL). This shows the ability of the multifunctional POSS and IL to work symbiotically to achieve the desirable proton conductivity and mechanical properties of such membranes by enhancing the ionic interaction within the material.
Tetraalkylphosphonium Polyoxometalates as Novel Ionic Liquids
The pairing of a Lindqvist or Keggin polyoxometalate (POM) anion with an appropriate tetraalkylphosphonium cation, [R 3 R P] + , has been shown to yield an original family of ionic liquids (POM-ILs), among them salts liquid at or near ambient temperature. The physicochemical properties of several such "inorganic liquids", in particular their thermal properties, suggests the possible application of these compounds as robust, thermally-stable solvents for liquid-liquid extraction. A preliminary evaluation of the potential of POM-ILs in this application is presented.
Solid polymer electrolytes (SPEs) using polymer poly(ethylene oxide) (PEO), lithium salt bis(trifluoromethylsulfonyl) imide (LiTFSI) and ionic liquid (IL) trihexyltetradeylphosphonium bis(trifluoromethylsulfonyl)imide have been prepared. These prepared solid polymer electrolyte films have been characterised by using different experimental techniques: X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermo gravimetric analysis (TGA), complex impedance spectroscopy, Fourier transform infrared spectroscopy (FTIR), an electrochemical analyser etc. Changes in crystallinity, melting temperature (T m), glass transition temperature (T g), thermal stability and ionic transport behaviour of the prepared polymer electrolyte have been observed when the LiTFSI salt and different concentrations of IL were incorporated in the pristine polymer PEO. Ionic conductivity of the prepared solid polymer electrolyte (PEO + 20 wt% LiTFSI) has been found to increase with increasing IL concentration in polymer electrolytes up to 20 wt% IL. Total ionic transference number >0.99 and cationic transference number 0.37withanelectrochemicalwindowof0.37 with an electrochemical window of 0.37withanelectrochemicalwindowof3.34 V has been observed for the optimized solid polymer electrolyte (PEO + 20 wt% LiTFSI + 20 wt% IL). Temperature dependant ionic conductivity obeys Arrhenius type thermally activated behaviour.
Electrochimica Acta, 2011
A series of bis(trifluoromethylsulfonyl)amide based "polymeric ionic liquids" (PILs) as high molecular mass analogues of the corresponding imidazolium, ammonium and pyrrolidinium ionic liquids (ILs) was synthesized with high purity and fully characterized including electrochemical properties. The PILs differed by the nature of the cation, the quantity of the ionic centers in each monomer repeating unit, and the alkyl length of the spacer. Two novel ionic liquid like monomers (ILMs), namely 1,3bis(N,N,N-trimethylammonium)-2-propylmethacrylate bis(trifluoromethylsulfonyl) amide (ILM-2) and N-[(2-methacryloyloxy)-ethyl]-N-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide (ILM-4) were synthesized and characterized. Optimal conditions for the free-radical polymerization of the ILMs were identified for the first time. It was demonstrated that, among the tested organic solvents, 1-methyl-3-ethylimidazolium bis(trifluoromethylsulfonyl)amide IL was the best reaction medium in terms of the achievement of high polymer yields and molecular masses. For the first time, the influence of the residual monomer presence inside the PIL film on the resultant conductivity was clearly shown. The impact of the molecular mass of the PILs on the ionic conductivity was firstly studied as well. Finally, the copolymerization of ILMs with poly(ethylene glycol)dimethacrylate (PEGDM) was carried out yielding tight elastic films with the highest conductivity equal to 3.2 × 10 −6 S/cm at 25 о C. .ru (A.S. Shaplov).
The Journal of Chemical Thermodynamics, 2011
In this work, the solubility of water in several tetradecyltrihexylphosphonium-based ionic liquids at 298.15 K, and densities and viscosities of both pure and water-saturated ionic liquids in a broad temperature range were measured. The selected ionic liquids comprise the common tetradecyltrihexylphosphonium cation combined with the following anions: bromide, chloride, bis(trifluoromethylsulfonyl)imide, decanoate, methanesulfonate, dicyanamide and bis(2,4,4-trimethylpentyl)phosphinate. The isobaric thermal expansion coefficients for pure and water-saturated ionic liquids were determined based on the density dependence with temperature. Taking into account that the excess molar volumes of the current hydrophobic water-saturated ionic liquids are negligible, the solubility of water was additionally estimated from the gathered density data and compared with the experimental solubilities obtained. Moreover, the experimental densities were compared with those predicted by the Gardas and Coutinho model while viscosity data were correlated using the Vogel-Tammann-Fulcher method.
Density, Viscosity, and Conductivity of Tetraalkyl Phosphonium Ionic Liquids
ECS Transactions, 2006
The density, viscosity and conductivity of nine commercially available tetra-alkyl phosphonium ionic liquids (ILs) are presented. The effect of cation volume and symmetry, anion volume, and temperature are observed. The Vogel-Tamman-Fulcher (VTF) equation is used to calculate the theoretical glass transition temperature (T 0 ) and the activation energy of conductivity E a,Λ . The conductivity of three halo-aluminate ionic liquid systems for mole fractions up to 0.7 AlCl 3 is reported.