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Siddharth Pandey - One of the best experts on this subject based on the ideXlab platform.
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solvatochromic absorbance probe behavior within 1 butyl 3 methylimidazolium Hexafluorophosphate propylene carbonate preferential solvation or solvent solvent interaction
Chemical Engineering Journal, 2009Co-Authors: Shruti Trivedi, Abhra Sarkar, Siddharth PandeyAbstract:Abstract Physicochemical properties of ionic liquids (ILs) can be favorably modified by addition of appropriate cosolvents. Solvatochromic absorbance probes are used to assess physicochemical properties of the mixture of a common IL 1-Butyl-3-Methylimidazolium Hexafluorophosphate ([bmim][PF6]) and propylene carbonate. Parameter E T N obtained from electronic absorbance of Reichardt's betaine dye within the mixture is observed to be higher than that predicted from ideal additive behavior. Absorbance from N,N-diethyl-4-nitroaniline and 4-nitroaniline in concert with absorbance from Reichardt's dye is used to obtain dipolarity/polarizability (π*), hydrogen-bond donating (HBD) acidity (α), and hydrogen-bond accepting (HBA) basicity (β) of the mixture. While π* and α of the mixture are observed to be higher than those expected from ideal additive behavior, β is observed to be lower. Solvatochromic absorbance probe behavior suggests solute-specific preferential solvation; FTIR absorbance of the mixture implies negligible specific solvent–solvent interaction(s) within the mixture. Combined nearly ideal binary solvent/Redlich–Kister (CNIBS/R–K) equation is demonstrated to predict the solvatochromic parameters satisfactorily.
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multiprobe spectroscopic evidence for hyperpolarity within 1 butyl 3 methylimidazolium Hexafluorophosphate mixtures with tetraethylene glycol
Journal of Physical Chemistry B, 2008Co-Authors: Abhra Sarkar, Shruti Trivedi, Gary A Baker, Siddharth PandeyAbstract:A hybrid, potentially green solvent system composed of tetraethylene glycol (TEG) and the ionic liquid 1-Butyl-3-Methylimidazolium Hexafluorophosphate ([bmim][PF6]) was investigated across all mole fractions with regard to the solvent properties of the mixture. For this purpose, a suite of absorbance- and fluorescence-based solvatochromic probes were utilized to explore solute−solvent and solvent−solvent interactions existing within the [bmim][PF6] + TEG system. These studies revealed an interesting and unusual synergistic solvent effect. In particular, a remarkable “hyperpolarity” was observed in which the ET value, comprising dipolarity/polarizability and hydrogen bond donor (HBD) acidity contributions, at intermediate mole fractions of the binary mixture well exceeded that of the most polar pure component (i.e., [bmim][PF6]). Independently determined dipolarity/polarizability (π*) and HBD acidity (α) Kamlet-Taft values for the [bmim][PF6] + TEG mixtures were also observed to be anomalously high at inte...
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unusual solvatochromism within 1 butyl 3 methylimidazolium Hexafluorophosphate poly ethylene glycol mixtures
Journal of Physical Chemistry B, 2008Co-Authors: Abhra Sarkar, Shruti Trivedi, Siddharth PandeyAbstract:Hybrid “green” solvent systems composed of room-temperature ionic liquids (ILs) and poly(ethylene glycols) (PEGs) may have enormous future potential. Solvatochromic absorbance probe behavior is used to assess the physicochemical properties of the mixture composed of IL 1-Butyl-3-Methylimidazolium Hexafluorophosphate ([bmim][PF6]) and PEG (average molecular weights of 200, 400, 600, and 1500) at ambient conditions. Lowest energy intramolecular charge-transfer absorbance maxima of a betaine dye, i.e., ETN, indicates the dipolarity/polarizability and/or hydrogen-bond donating (HBD) acidity of the [bmim][PF6] + PEG mixtures to be even higher than that of neat [bmim][PF6], the solution component with higher dipolarity/polarizability and/or HBD acidity. Dipolarity/polarizability (π*) obtained separately from the electronic absorbance response of probe N,N-diethyl-4-nitroaniline shows a trend similar to ETN thus confirming the unusually high dipolarity/polarizability of the [bmim][PF6] + PEG mixtures. Similar to...
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solvatochromic probe behavior within ternary room temperature ionic liquid 1 butyl 3 methylimidazolium Hexafluorophosphate ethanol water solutions
Journal of Physical Chemistry B, 2003Co-Authors: Kristin A Fletcher, Siddharth PandeyAbstract:The solvatochromic probe behavior within ternary BMIMPF6 + ethanol + water systems were investigated using four solvatochromic probes: pyrene, 1,3-bis(1-pyrenyl)propane, 1-pyrenecarboxaldehyde, an...
Ana Rodriguez - One of the best experts on this subject based on the ideXlab platform.
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ternary liquid liquid equilibria ethanol 2 butanone 1 butyl 3 methylimidazolium Hexafluorophosphate 2 propanol 2 butanone 1 butyl 3 methylimidazolium Hexafluorophosphate and 2 butanone 2 propanol 1 3 dimethylimidazolium methyl sulfate at 298 15 k
Journal of Chemical & Engineering Data, 2007Co-Authors: Ana Pereiro B And, Ana RodriguezAbstract:This research is focused on a study of the ionic liquid as a solvent in liquid−liquid extraction of azeotropic mixtures. Liquid−liquid equilibria (LLE) were determined for the ternary systems ethanol + 2-butanone + 1-Butyl-3-Methylimidazolium Hexafluorophosphate ([BMIM][PF6]), 2-propanol + 2-butanone + [BMIM][PF6], and 2-butanone + 2-propanol + 1,3-dimethylimidazolium methyl sulfate ([MMIM][MeSO4]) at 298.15 K and atmospheric pressure. Selectivity and distribution ratio values, derived from the tie lines data, were calculated. Experimental LLE data were correlated by means of the nonrandom two-liquid, Othmer−Tobias, and Hand equations. The plait point compositions have been calculated by the Hand method.
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Study on the phase behaviour and thermodynamic properties of ionic liquids containing imidazolium cation with ethanol at several temperatures
The Journal of Chemical Thermodynamics, 2007Co-Authors: Ana B. Pereiro, Ana RodriguezAbstract:Abstract Experimental densities, speeds of sound and refractive indices of the binary mixtures of ethanol with MMIM MeSO4 (1,3-dimethylimidazolium methyl sulfate), BMIM MeSO4 (1-Butyl-3-Methylimidazolium methyl sulfate), BMIM PF6 (1-Butyl-3-Methylimidazolium Hexafluorophosphate), HMIM PF6 (1-hexyl-3-methylimidazolium Hexafluorophosphate) and OMIM PF6 (1-methyl-3-octylimidazolium Hexafluorophosphate) were determined from T = (293.15 to 303.15) K. Excess molar volumes, changes of refractive index on mixing and deviations in isentropic compressibility for the above systems were calculated. The (liquid + liquid) equilibrium (LLE) data of (IL + ethanol) were carried out experimentally and the NRTL and UNIQUAC correlative equation was applied to these mixtures.
Christopher S Brazel - One of the best experts on this subject based on the ideXlab platform.
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an investigation into the degree and rate of polymerization of poly methyl methacrylate in the ionic liquid 1 butyl 3 methylimidazolium Hexafluorophosphate
Polymer International, 2004Co-Authors: Michael G Benton, Christopher S BrazelAbstract:Room-temperature ionic liquids (ILs), including 1-Butyl-3-Methylimidazolium Hexafluorophosphate, [bmim+][PF6−], were investigated as replacements for volatile organic compounds in the free-radical solution polymerization of poly(methyl methacrylate) (PMMA). The latter was synthesized in benzene and [bmim+][PF6−] at 70 °C via a free-radical process and the degree and rate of polymerization were compared based on the solvent used. The degree of polymerization was found to be five times higher in [bmim+][PF6−] than in benzene, while the rate of reaction was approximately four times faster in [bmim+][PF6−]. The results indicate the potential for using ILs to produce high-molecular-weight polymers and block structures based on the increased free-radical stability in ILs. Copyright © 2004 Society of Chemical Industry
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application of ionic liquids as plasticizers for poly methyl methacrylate
Chemical Communications, 2002Co-Authors: Mark P Scott, John D. Holbrey, Michael G Benton, Christopher S Brazel, Jimmy W Mays, Robin D RogersAbstract:The room temperature ionic liquid, 1-Butyl-3-Methylimidazolium Hexafluorophosphate, [C4mim][PF6] was found to be an efficient plasticizer for poly(methyl methacrylate), prepared by in situ radical polymerization in the ionic liquid medium; the polymers have physical characteristics comparable with those containing traditional plasticizers and retain greater thermal stability.
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conventional free radical polymerization in room temperature ionic liquids a green approach to commodity polymers with practical advantages
Chemical Communications, 2002Co-Authors: John D. Holbrey, Christopher S Brazel, Jimmy W Mays, Kunlun Hong, Hongwei Zhang, Ann E Visser, Matthew W ReichertAbstract:Free-radical polymerization of methyl methacrylate and styrene using conventional organic initiators in the room temperature ionic liquid, 1-Butyl-3-Methylimidazolium Hexafluorophosphate ([C4mim][PF6]) is rapid and produces polymers with molecular weights up to 10× higher than from benzene; both polymerization and isolation of products were achieved without using VOCs, offering economic as well as environmental advantages.
Robin D Rogers - One of the best experts on this subject based on the ideXlab platform.
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Ionic liquids are not always green: hydrolysis of 1-Butyl-3-Methylimidazolium Hexafluorophosphate
Green Chemistry, 2003Co-Authors: Richard P Swatloski, John D. Holbrey, Robin D RogersAbstract:1-Butyl-3-Methylimidazolium fluoride hydrate has been identified crystallographically as a decomposition product created during purification of the hydrophobic ionic liquid 1-Butyl-3-Methylimidazolium Hexafluorophosphate. This highlights the need to treat ionic liquids much as one would any other research chemical with potentially hazardous properties, unknown toxicity and/or stability, particularly when searching for ‘green solvents’.
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application of ionic liquids as plasticizers for poly methyl methacrylate
Chemical Communications, 2002Co-Authors: Mark P Scott, John D. Holbrey, Michael G Benton, Christopher S Brazel, Jimmy W Mays, Robin D RogersAbstract:The room temperature ionic liquid, 1-Butyl-3-Methylimidazolium Hexafluorophosphate, [C4mim][PF6] was found to be an efficient plasticizer for poly(methyl methacrylate), prepared by in situ radical polymerization in the ionic liquid medium; the polymers have physical characteristics comparable with those containing traditional plasticizers and retain greater thermal stability.
John D. Holbrey - One of the best experts on this subject based on the ideXlab platform.
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Ionic liquids are not always green: hydrolysis of 1-Butyl-3-Methylimidazolium Hexafluorophosphate
Green Chemistry, 2003Co-Authors: Richard P Swatloski, John D. Holbrey, Robin D RogersAbstract:1-Butyl-3-Methylimidazolium fluoride hydrate has been identified crystallographically as a decomposition product created during purification of the hydrophobic ionic liquid 1-Butyl-3-Methylimidazolium Hexafluorophosphate. This highlights the need to treat ionic liquids much as one would any other research chemical with potentially hazardous properties, unknown toxicity and/or stability, particularly when searching for ‘green solvents’.
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application of ionic liquids as plasticizers for poly methyl methacrylate
Chemical Communications, 2002Co-Authors: Mark P Scott, John D. Holbrey, Michael G Benton, Christopher S Brazel, Jimmy W Mays, Robin D RogersAbstract:The room temperature ionic liquid, 1-Butyl-3-Methylimidazolium Hexafluorophosphate, [C4mim][PF6] was found to be an efficient plasticizer for poly(methyl methacrylate), prepared by in situ radical polymerization in the ionic liquid medium; the polymers have physical characteristics comparable with those containing traditional plasticizers and retain greater thermal stability.
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conventional free radical polymerization in room temperature ionic liquids a green approach to commodity polymers with practical advantages
Chemical Communications, 2002Co-Authors: John D. Holbrey, Christopher S Brazel, Jimmy W Mays, Kunlun Hong, Hongwei Zhang, Ann E Visser, Matthew W ReichertAbstract:Free-radical polymerization of methyl methacrylate and styrene using conventional organic initiators in the room temperature ionic liquid, 1-Butyl-3-Methylimidazolium Hexafluorophosphate ([C4mim][PF6]) is rapid and produces polymers with molecular weights up to 10× higher than from benzene; both polymerization and isolation of products were achieved without using VOCs, offering economic as well as environmental advantages.
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solubilization of an ionic liquid 1 butyl 3 methylimidazolium Hexafluorophosphate in a surfactant water system
Journal of Dispersion Science and Technology, 2000Co-Authors: Stig E Friberg, John D. Holbrey, Kenneth R Seddon, Qi Yin, Florentina Pavel, Raymond A Mackay, Patricia A AikensAbstract:Abstract The amphiphilic association structures were determined in the system; water, Laureth 4 (approximately C12(EO) 4), and the ionic liquid l-butyl-3-methylimidazolium Hexafluorophosphate ([bmim[PF6]), using visual observation and small angle x-ray diffraction. The system showed a lamellar liquid crystal solubilizing the ionic liquid ([bmim[PF6]) to a maximum of 15%, an isotropic surfactant solution dissolving the ionic liquid to a maximum of 39%, an isotropic ionic liquid solution with less than 0.5% of water and surfactant and finally, an aqueous solution with only traces of surfactant and ionic liquid. The small angle x-ray diffraction results showed the ionic liquid to be solubilized into the lamellar liquid crystal without changing the dimensions of the amphiphile layer or the interlayer spacing dependence on the water content.
