The Hildebrand Solubility Parameters of Ionic Liquids—Part 2

The Hildebrand solubility parameters have been calculated for eight ionic liquids. Retention data from the inverse gas chromatography measurements of the activity coefficients at infinite dilution were used for the calculation. From the solubility parameters, the enthalpies of vaporization of ionic liquids were estimated. Results are compared with solubility parameters estimated by different methods

Comparative Proteomics of Inner Membrane Fraction from Carbapenem-Resistant Acinetobacter baumannii with a Reference Strain

Acinetobacter baumannii has been identified by the Infectious Diseases Society of America as one of the six pathogens that cause majority of hospital infections. Increased resistance of A. baumannii even to the latest generation of β-lactams like carbapenem is an immediate threat to mankind. As inner-membrane fraction plays a significant role in survival of A. baumannii, we investigated the inner-membrane fraction proteome of carbapenem-resistant strain of A. baumannii using Differential In-Gel Electrophoresis (DIGE) followed by DeCyder, Progenesis and LC-MS/MS analysis. We identified 19 over-expressed and 4 down-regulated proteins (fold change>2, p<0.05) in resistant strain as compared to reference strain. Some of the upregulated proteins in resistant strain and their association with carbapenem resistance in A. baumannii are: i) β-lactamases, AmpC and OXA-51: cleave and inactivate carbapenem ii) metabolic enzymes, ATP synthase, malate dehydrogenase and 2-oxoglutarate dehydrogenase: help in increased energy production for the survival and iii) elongation factor Tu and ribosomal proteins: help in the overall protein production. Further, entry of carbapenem perhaps is limited by controlled production of OmpW and low levels of surface antigen help to evade host defence mechanism in developing resistance in A. baumannii. Present results support a model for the importance of proteins of inner-membrane fraction and their synergistic effect in the mediation of resistance of A. baumannii to carbapenem

CO2 separation applying ionic liquid mixtures: the effect of mixing different anions on gas permeation through supported ionic liquid membranes

In order to increase flexibility in tailoring the permeability and selectivity of supported ionic liquid membranes (SILMs) for flue gas separation and natural gas purification, this work explores the use of ionic liquid mixtures. For that purpose, gas permeation properties of CO2, CH4 and N-2 in several binary ionic liquid mixtures based on a common cation ([C(2)mim](+)) and different anions such as bis(trifluoromethyl-sulfonyl) imide ([NTf2](-)), acetate ([Ac](-)), lactate ([Lac](-)), dicyanamide ([DCA](-)) and thiocyanate ([SCN](-)) were measured at 293 K using a time-lag apparatus. In addition to gas permeation results, the thermophysical properties of those mixtures, namely viscosity and density, were also determined so that trends between the two types of properties could be evaluated. The results show that mixing [Ac](-) or [Lac](-) with [NTf2](-) promotes the decrease of gas permeability and diffusivity of the SILMs based on those binary mixtures, essentially due to their high viscosities. The pure ionic liquids containing anions with nitrile groups, [DCA](-) or [SCN](-), and also their mixtures with [C(2)mim][NTf2] exhibit permselectivities ranging from 19.1 to 23.0 for CO2/CH4, and from 36.6 to 67.8 for CO2/N-2, as a consequence of a reduction in the CH4 and N-2 permeabilities, respectively. Furthermore, it is shown that mixing anions with different chemical features allows variations in ionic liquid viscosity and molar volume that impact the gas permeation properties of SILMs, offering a clear pathway for the optimization of their CO2 separation performances

Ionic liquids at electrified interfaces

Until recently, “room-temperature” (<100–150 °C) liquid-state electrochemistry was mostly electrochemistry of diluted electrolytes(1)–(4) where dissolved salt ions were surrounded by a considerable amount of solvent molecules. Highly concentrated liquid electrolytes were mostly considered in the narrow (albeit important) niche of high-temperature electrochemistry of molten inorganic salts(5-9) and in the even narrower niche of “first-generation” room temperature ionic liquids, RTILs (such as chloro-aluminates and alkylammonium nitrates).(10-14) The situation has changed dramatically in the 2000s after the discovery of new moisture- and temperature-stable RTILs.(15, 16) These days, the “later generation” RTILs attracted wide attention within the electrochemical community.(17-31) Indeed, RTILs, as a class of compounds, possess a unique combination of properties (high charge density, electrochemical stability, low/negligible volatility, tunable polarity, etc.) that make them very attractive substances from fundamental and application points of view.(32-38) Most importantly, they can mix with each other in “cocktails” of one’s choice to acquire the desired properties (e.g., wider temperature range of the liquid phase(39, 40)) and can serve as almost “universal” solvents.(37, 41, 42) It is worth noting here one of the advantages of RTILs as compared to their high-temperature molten salt (HTMS)(43) “sister-systems”.(44) In RTILs the dissolved molecules are not imbedded in a harsh high temperature environment which could be destructive for many classes of fragile (organic) molecules

Nanoscale Organic Hybrid Electrolytes

Nanoscale organic hybrid electrolytes are composed of organic-inorganic hybrid nanostructures, each with a metal oxide or metallic nanoparticle core densely grafted with an ion-conducting polyethylene glycol corona doped with lithium salt. These materials form novel solvent-free hybrid electrolytes that are particle-rich, soft glasses at room temperature; yet manifest high ionic conductivity and good electrochemical stability above 5V.Work on synthesis and mechanical characterization of nanoscale organic hybrid materials (NOHMs) was supported by Award No. KUS-C1-018-02, made by King Abdullah University of Science and Technology (KAUST). Our research on electrochemical characterization of NOHMs was supported by the Department of Energy Basic Energy Sciences program (Grant DE-FG02-07ER46455)). JN acknowledges support from a National Science Foundation Sustainable Materials IGERT fellowship program at Cornell

Ionic liquid-nanoparticle hybrid electrolytes

e investigate physical and electrochemical properties of a family of organic-inorganic hybrid electrolytes based on the ionic liquid 1-methyl-3-propylimidazolium bis(trifluoromethanesulfone) imide covalently tethered to silica nanoparticles (SiO2-IL-TFSI). The ionic conductivity exhibits a pronounced maximum versus LiTFSI composition, and in mixtures containing 13.4 wt% LiTFSI, the room-temperature ionic conductivity is enhanced by over 3 orders of magnitude relative to either of the mixture components, without compromising lithium transference number. The SiO2-IL-TFSI/LiTFSI hybrid electrolytes are thermally stable up to 400 °C and exhibit tunable mechanical properties and attractive (4.25V) electrochemical stability in the presence of metallic lithium. We explain these observations in terms of ionic coupling between counterion species in the mobile and immobile (particle-tethered) phases of the electrolytes.This publication was based on work supported in part by Award No. KUS-C1-018-02, made by King Abdullah University of Science and Technology (KAUST) and by the National Science Foundation, Award No. DMR-1006323. Facilities available through the Cornell Center for Materials Research(CCMR),National Science Foundation Award No. DMR-1120296, were also used for this study

Nanoporous hybrid electrolytes

Oligomer-suspended SiO(2)-polyethylene glycol nanoparticles are studied as porous media electrolytes. At SiO(2) volume fractions, phi, bracketing a critical value phi(y) approximate to 0.29, the suspensions jam and their mechanical modulus increase by more than seven orders. For phi > phi(y), the mean pore diameter is close to the anion size, yet the ionic conductivity remains surprisingly high and can be understood, at all phi, using a simple effective medium model proposed by Maxwell. SiO(2)-polyethylene glycol hybrid electrolytes are also reported to manifest attractive electrochemical stability windows (0.3-6.3 V) and to reach a steady-state interfacial impedance when in contact with metallic lithium.This work was supported by Award No. KUS-C1-018-02, made by King Abdullah University of Science and Technology (KAUST), and by the National Science Foundation, Award No. DMR-1006323. JLN also acknowledges support from the Materials for a Sustainable Future IGERT program, NSF grant # DGE-0903653