Influence of an Oxygen Functionalization on the Physicochemical Properties of Ionic Liquids: Density, Viscosity, and Carbon Dioxide Solubility as a Function of Temperature (original) (raw)
Related papers
Fluid Phase Equilibria, 2014
Experimental data on density, viscosity, refractive index and surface tension of four ILs: 1-Methyl-1propylpiperidinium bis(trifluoromethylsulfonyl)imide [C 3 C 1 Pip][NTf 2 ], 1-Butyl-1-methylpiperidinium bis(trifluoromethylsulfonyl)imide [C 4 C 1 Pip][NTf 2 ], 3-Methyl-1-propylpyridinium bis(trifluoromethylsulfonyl)imide [C 3 C 1 Py][NTf 2 ] and 1-Butyl-3-methylpyridinium bis(trifluoromethylsulfonyl)imide [C 4 C 1 Py][NTf 2 ] were measured in the temperature range between 288.15 and 353.15 K and at atmospheric pressure to evaluate the impact of the cation's aromaticity upon the thermophysical properties of ionic liquids. The properties investigated show that the pyridinium aromatic ring, with itsinteractions, leads to a more rigid, compact and organized liquid phase, while the less rigid structure of the piperidinium cation induces more entanglement and consequently higher resistance to shear stress (higher viscosities) and better surface arrangement (higher surface tensions). The group contribution methods proposed by Gardas and Coutinho were also evaluated and fitted to the experimental data, allowing the proposal of new parameters for the cations investigated.
2013
The first area of the research presented in this thesis pertains to the synthesis and characterisation of novel ionic liquids. Three distinct categories of ionic liquids were synthesised, two of which are imidazolium based, with the latter category based on the phosphonium cations. The first category consist of cations which contain two N-heterocyclic rings and these are combined with a range of conventional anions such as bis(triflimide) and dicyanamide. The second category utilise the same cations but have amino acids as the anion in their carboxylate form, introducing NH2 functionality into the ionic liquids and as such can be used in CO2 absorption investigations. The last category of ionic liquids, are those which contain a phosphonium cation (trioctyl) quaternised with a number of groups containing different functionalities for different potential applications. In particular a pyrrole functionalised quaternary phosphonium salt was successfully polymerised. The novel ionic liqu...
Journal of Chemical Thermodynamics, 2009
a b s t r a c t Densities and viscosities of two pyridinium-based ionic liquids, 1-butylpyridinium tetrafluoroborate [BuPy][BF 4 ] and 1-octylpyridinium tetrafluoroborate [OcPy][BF 4 ], and their binaries with water at atmospheric pressure and temperatures from (283.15 to 348.15) K were determined. The densities and viscosities of pure ionic liquids were correlated successfully by empirical equations. The Vogel-Fulcher-Tammann equations can fit the experimental viscosities for pure and binary of both IL systems. Excess molar volume and viscosity deviation were calculated for the binaries. The excess molar volumes have positive deviation from ideal solution while the viscosity deviations have negative values.
Solubility of CO2 in pyridinium based ionic liquids
Chemical Engineering Journal, 2012
The solubility of CO 2 in six pyridinium based ionic liquids 1-butylpyridinium bis(trifluoromethylsulfonyl)imide [C 4 py][Tf 2 N], 1-octylpyridinium bis(trifluoromethylsulfonyl)imide [C 8 py][Tf 2 N], 1-decylpyridinium bis(trifluoromethylsulfonyl)imide [C 10 py][Tf 2 N], 1-dodecylpyridinium bis(trifluoromethylsulfonyl)imide [C 12 py][Tf 2 N], 1-butylpyridinium trifluoroacetate [C 4 py][TfAc] and 1-butylpyridinium dicyanamide [C 4 py][Dca] was measured at temperatures of 298.15 K, 313.15 K and 333.15 K and in the pressure range from 0.25 bar to 10 bar. The results showed that the solubility of CO 2 increase with increasing pressure and decrease with increasing temperature. The solubility of CO 2 in this six ionic liquids at 298.15 K was in the sequence of [C 12 py][Tf 2 N] > [C 10 py][Tf 2 N] > [C 8 py][Tf 2 N] > [C 4 py][Tf 2 N] > [C 4 py][TfAc] > [C 4 py][Dca]. The Henry's law constants, partial molar enthalpy and partial molar entropy of dissolution of CO 2 gas in these ionic liquids, were also estimated. The regeneration and recyclability studies of [C 4 py][Tf 2 N] proved their thermal and physical stability for commercial applications.
Journal of Chemical & Engineering Data, 2010
Density and viscosity data for six pyridinium-based ionic liquids combined with the bis[(trifluoromethyl)sulfonyl]amide anion were measured at atmospheric pressure in the (278 to 363) K temperature range. The fundamental aim of this work is to study the effect of the structure of the pyridinium-based cation, namely, its alkyl chain length and structural isomers, and the position of the second alkyl substitution on the measured properties. Albeit many studies exist on the physical properties of ionic liquids in what concerns the nature of the anion and the length of the cation alkyl side chain, the effect of structural and positional isomerism on those properties is much less known. In additionsand since small amounts of water influence the phase equilibrium and thermophysical properties of ionic liquidsswater-saturated ionic liquid samples were also studied in the (298 to 363) K temperature range. The Vogel-Tammann-Fulcher (VTF) method was applied to describe the viscosity data, and novel group contribution parameters are proposed for the ionic liquid cations presented here, thus broadening its applicability.
Journal of Solution Chemistry, 2007
Experimental values for the solubility of carbon dioxide and hydrogen in three room temperature ionic liquids based on the same anion-(bistrifluoromethylsulfonyl)imide [Ntf 2 ]-and three different cations-1-butyl-3-methylimidazolium, [C 4 mim], 1-ethyl-3methylimidazolium, [C 2 mim] and trimethyl-butylammonium, [N 4111 ]-are reported between 283 and 343 K and close to atmospheric pressure. Carbon dioxide, with a molefraction solubility of the order of 10 −2 , is two orders of magnitude more soluble than hydrogen. The solubility of CO 2 is very similar in the three ionic liquids although slightly lower in the presence of the [C 2 mim] cation. In the case of H 2 , noticeable differences were observed with larger mole fraction solubilities in the presence of [N 4111 ] followed by [C 4 mim]. All of the mole-fraction solubilities decrease with increasing temperature. From the variation of Henry's law constants with temperature, the thermodynamic functions of solvation were calculated. The precision of the experimental data, considered as the average absolute deviation of the Henry's law constants from appropriate smoothing equations, is always better than ±1%.
Experimental and Theoretical Study of Two Pyridinium-Based Ionic Liquids
Journal of Solution Chemistry, 2012
Structurally modified hydroxyl functionalized pyridinium ionic liquids (ILs), liquid at room temperature, were synthesized and characterized. Alkylated N-(2-hydroxyethyl)-pyridinium ILs were prepared from alkylpyridines via corresponding bromide salts by N-alkylation (65-93%) and final anion exchange (75-96%). Pyridinium-alkylation strongly influenced the IL physicochemical and electrochemical properties. Experimental values for the ILs physicochemical properties (density, viscosity, conductivity, and thermal decomposition temperature), were in good agreement with corresponding predicted values obtained by theoretical calculations. The pyridinium ILs have electrochemical window of 3.0-5.4 V and were thermally stable up to 405 • C. The IL viscosity and density were measured over a wide temperature range (25-80 • C). Pyridine alkyl-substitution strongly affected the partial positive charge on the nitrogen atom of the pyridinium cations, as shown by charge distribution calculations. Ongoing studies on Mg complexes of the new ILs demonstrate promising properties for high current density electrodeposition of magnesium.
Journal of Molecular Liquids, 2017
The structure and interactions of a series of ionic liquids composed of N-alkyl pyridinium cation ([C n Py] + , n = 2, 4, 6, 8, 10, 12, 14) with varied anions like bromide (Br-), tetrafluoroborate ([BF 4 ]-), bis(trifluoromethanolsulfonyl)imide ([NTf 2 ]-) and hexafluorophosphate ([PF 6 ]-) were investigated using ATR-FTIR and Raman spectroscopy. The observed frequencies were compared to the frequencies computed by means of DFT theory at the B3LYP/6-311++G(d,p) level. Significant variations were observed in the vibrational spectra of the pyridinium based ionic liquids, with increasing chain length of the alkyl group in the cation. The nature and extent of the chain-length dependent variations in the spectra was also dependent on the anionic species present in the sample. Comparison of the observed spectra to the computed spectra and previously reported data for imidazolium based ionic liquids indicate mesoscopic segregation of polar and nonpolar regions in the pyridinium ionic liquids. The strength of the cation-anion interaction determines the nature and extent of such microscopic heterogeneity, which is reflected in the anion-specific variations in the vibrational spectra. While the mesoscopic reorganization of pyridinium based ionic liquids is analogous to that in imidazolium based ionic liquids, some important differences have also been noted. The observations highlight the importance of all three structural featurescation, anion and alkyl chain lengthin determining the microscopic organization and properties of ionic liquids. The results emphasize the need for broadening the scope of ionic liquid research to include more studies on the non-imidazolium based ionic liquids.
Industrial & Engineering Chemistry Research, 2007
This paper examines the dependence of gas solubility on the surface tension of room-temperature ionic liquids (RTILs). The solubility phenomena of the CO 2 , ethylene, propylene, 1-butene, and 1,3-butadiene in five imidazolium-, four phosphonium-, and eight ammonium-based RTILs are explained using the Hansen RTIL solubility parameters that were calculated from surface tension measurements. The Hansen solubility parameters were estimated from the surface tensions of the respective RTILs with a proportionality constant that is a function of the ratio of the number of nearest-neighbor interactions in the bulk liquid to those on the surface. The calculated solubility parameters are almost independent of temperature. The surface tension solubility parameter model explains the effect of variation of alkyl chain lengths in the cations and the variation of the RTIL anions on gas solubility within an error of (15%. The analysis may indicate that the CO 2-anion interaction is not the dominant factor that determines the relative CO 2 solubility between RTILs.