Sample records for n-methyl-n-butyl pyrrolidinium bistrifluoromethane

  1. Study of a Li-air battery having an electrolyte solution formed by a mixture of an ether-based aprotic solvent and an ionic liquid

    NASA Astrophysics Data System (ADS)

    Cecchetto, Laura; Salomon, Mark; Scrosati, Bruno; Croce, Fausto


    Recent studies have clearly demonstrated that cyclic and linear carbonates are unstable when used in rechargeable Li-air batteries employing aprotic solvents mostly due to the cathodic formation of superoxide during the oxygen reduction reaction. In particular, it has been ascertained that nucleophilic attack by superoxide anion radical, O2-rad , at O-alkyl carbon is a common mechanism of decomposition of organic carbonates. Moreover, theoretical calculations showed that ether chemical functionalities are stable against nucleophilic substitution induced by superoxide. Aim of this study is to report on a new electrolyte solution for Li-air battery formed by a mixture of an ether-based aprotic solvent with an ionic liquid (IL). The IL-based electrolyte was obtained by mixing the pure ionic liquid N-methyl-(n-butyl) pyrrolidinium bis(trifluoromethane sulfonyl) imide (here denoted as PYR14TFSI) to a 0.91 M solution of lithium triflate (LiCF3SO3) in tetra ethylene glycol dimethyl etcher (TEGDME). We observed that the presence of IL beneficially affects the kinetics and the reversibility of the oxygen reactions involved at the cathode. The most significant result being a lower overvoltage for the charge reaction, compared to a Li/air cell containing the same electrolyte solution without IL.

  2. Physicochemical properties and toxicities of hydrophobicpiperidinium and pyrrolidinium ionic liquids

    SciTech Connect

    Salminen, Justin; Papaiconomou, Nicolas; Kumar, R. Anand; Lee,Jong-Min; Kerr, John; Newman, John; Prausnitz, John M.


    Some properties are reported for hydrophobic ionic liquids (IL) containing 1-methyl-1-propyl pyrrolidinium [MPPyrro]{sup +}, 1-methyl-1-butyl pyrrolidinium [MBPyrro]{sup +}, 1-methyl-1-propyl piperidinium [MPPip]{sup +}, 1-methyl-1-butyl piperidinium [MBPip]{sup +}, 1-methyl-1-octylpyrrolidinium [MOPyrro]{sup +} and 1-methyl-1-octylpiperidinium [MOPip]{sup +} cations. These liquids provide new alternatives to pyridinium and imidazolium ILs. High thermal stability of an ionic liquid increases safety in applications like rechargeable lithium-ion batteries and other electrochemical devices. Thermal properties, ionic conductivities, viscosities, and mutual solubilities with water are reported. In addition, toxicities of selected ionic liquids have been measured using a human cancer cell-line. The ILs studied here are sparingly soluble in water but hygroscopic. We show some structure-property relationships that may help to design green solvents for specific applications. While ionic liquids are claimed to be environmentally-benign solvents, as yet few data have been published to support these claims.

  3. Pyrrolidinium fullerene induces apoptosis by activation of procaspase-9 via suppression of Akt in primary effusion lymphoma

    SciTech Connect

    Watanabe, Tadashi; Nakamura, Shigeo; Ono, Toshiya; Ui, Sadaharu; Yagi, Syota; Kagawa, Hiroki; Watanabe, Hisami; Ohe, Tomoyuki; Mashino, Tadahiko; Fujimuro, Masahiro


    Highlights: • Seven fullerenes were evaluated in terms of their cytotoxic effects on B-lymphomas. • Pyrrolidinium fullerene induced apoptosis of KSHV-infected B-lymphoma PEL cells. • The activation of Akt is essential for PEL cell survival. • Pyrrolidinium fullerene activated caspase-9 by inactivating Akt in PEL cells. • Pyrrolidinium fullerene have potential as novel drugs for the treatment of PEL. - Abstract: Primary effusion lymphoma (PEL) is a subtype of non-Hodgkin’s B-cell lymphoma and is an aggressive neoplasm caused by Kaposi’s sarcoma-associated herpesvirus (KSHV) in immunosuppressed patients. In general, PEL cells are derived from post-germinal center B-cells and are infected with KSHV. To evaluate potential novel anti-tumor compounds against KSHV-associated PEL, seven water-soluble fullerene derivatives were evaluated as potential drug candidates for the treatment of PEL. Herein, we discovered a pyrrolidinium fullerene derivative, 1,1,1′,1′-tetramethyl [60]fullerenodipyrrolidinium diiodide, which induced apoptosis of PEL cells via a novel mechanism, the caspase-9 activation by suppressing the caspase-9 phosphorylation, causing caspase-9 inactivation. Pyrrolidinium fullerene treatment reduced significantly the viability of PEL cells compared with KSHV-uninfected lymphoma cells, and induced the apoptosis of PEL cells by activating caspase-9 via procaspase-9 cleavage. Pyrrolidinium fullerene additionally reduced the Ser473 phosphorylation of Akt and Ser196 of procaspase-9. Ser473-phosphorylated Akt (i.e., activated Akt) phosphorylates Ser196 in procaspase-9, causing inactivation of procaspase-9. We also demonstrated that Akt inhibitors suppressed the proliferation of PEL cells compared with KSHV-uninfected cells. Our data therefore suggest that Akt activation is essential for cell survival in PEL and a pyrrolidinium fullerene derivative induced apoptosis by activating caspase-9 via suppression of Akt in PEL cells. In addition, we evaluated whether pyrrolidinium fullerene in combination with the HSP90 inhibitor (geldanamycin; GA) or valproate, potentiated the cytotoxic effects on PEL cells. Compared to treatment with pyrrolidinium fullerene alone, the addition of low-concentration GA or valproate enhanced the cytotoxic activity of pyrrolidinium fullerene. These results indicate that pyrrolidinium fullerene could be used as a novel therapy for the treatment of PEL.

  4. NMR investigation of ionic liquid-LiX mixtures: pyrrolidinium cations and TFSI- anions.


    Nicotera, Isabella; Oliviero, Cesare; Henderson, Wesley A; Appetecchi, Giovanni B; Passerini, Stefano


    In this paper is reported an extensive NMR characterization of N-methyl-N-propyl-pyrrolidinium bis(trifluoromethanesulfonyl)imide (PYR13TFSI) room-temperature ionic liquid and its mixtures with LiTFSI. NMR was used to investigate the interactions between the ionic liquid and lithium salt and the diffusion coefficients of all ionic species present in these mixtures. The results are compared with previous DSC, Raman, and electrochemical investigations. PMID:16853972

  5. Synthesis, growth, structural, thermal and optical studies of pyrrolidinium-2-carboxylate-4-nitrophenol single crystals

    NASA Astrophysics Data System (ADS)

    Swarna Sowmya, N.; Sampathkrishnan, S.; Vidyalakshmi, Y.; Sudhahar, S.; Mohan Kumar, R.


    Organic nonlinear optical material, pyrrolidinium-2-carboxylate-4-nitrophenol (PCN) was synthesized and single crystals were grown by slow evaporation solution growth method. Single crystal X-ray diffraction analysis confirmed the structure and lattice parameters of PCN crystals. Infrared, Raman and NMR spectral analyses were used to elucidate the functional groups present in the compound. The thermal behavior of synthesized compound was studied by thermogravimetric and differential scanning calorimetry (TG-DSC) analyses. The photoluminescence property was studied by exciting the crystal at 360 nm. The relative second harmonic generation (SHG) efficiency of grown crystal was estimated by using Nd:YAG laser with fundamental wavelength of 1064 nm.

  6. Synthesis, growth, structural, thermal and optical studies of pyrrolidinium-2-carboxylate-4-nitrophenol single crystals.


    Swarna Sowmya, N; Sampathkrishnan, S; Vidyalakshmi, Y; Sudhahar, S; Mohan Kumar, R


    Organic nonlinear optical material, pyrrolidinium-2-carboxylate-4-nitrophenol (PCN) was synthesized and single crystals were grown by slow evaporation solution growth method. Single crystal X-ray diffraction analysis confirmed the structure and lattice parameters of PCN crystals. Infrared, Raman and NMR spectral analyses were used to elucidate the functional groups present in the compound. The thermal behavior of synthesized compound was studied by thermogravimetric and differential scanning calorimetry (TG-DSC) analyses. The photoluminescence property was studied by exciting the crystal at 360 nm. The relative second harmonic generation (SHG) efficiency of grown crystal was estimated by using Nd:YAG laser with fundamental wavelength of 1,064 nm. PMID:25795607

  7. Interionic interactions of binary gels consisting of pyrrolidinium-based zwitterionic compounds and lithium salts.


    Park, HoSeok; Kim, Hoon Sik; Jung, Young Mee


    We demonstrated thermal transitions and physical gelation of binary ionic salts through interionic interactions, which consist of pyrrolidinium-N-propanesulfonate zwitterionic compound (PyrZIC) and lithium bis(trifluorosulfonyl)imide (LiTFSI). The transition behaviors of binary ionic gels were attributed to conformational changes in the cations and anions of PyrZIC and LiTFSI as analyzed by density functional theory (DFT), principal component analysis (PCA), and two-dimensional infrared correlation spectroscopy (2D IR COS). Furthermore, the geometries of binary PyrZIC-LiTFSI systems were strongly influenced by the electrostatic interactions between two ionic salts. The different dynamic processes in the PyrZIC- and LiTFSI-rich phases, which are classified by the transition point of PCA plots, were induced by the conformational changes in the respective interaction fields, as shown by 2D correlation spectra. In particular, LiTFSI-rich binary gels revealed characteristic four-leaf-clover and butterfly patterns under their unique chemical circumstances, which were different from those of PyrZIC-rich gels. Consequently, these computational and experimental investigations provide an analytical tool to understand the physical phenomenon and interactions occurring in the unveiled and complicated systems. PMID:21291183

  8. Combined measurement of translational and rotational diffusion in quaternary acyclic ammonium and cyclic pyrrolidinium ionic liquids.


    Alam, Todd M; Dreyer, Daniel R; Bielawski, Christopher W; Ruoff, Rodney S


    The translational self-diffusion coefficients (D(T)) for a series of tetra-alkyl acyclic ammonium and cyclic pyrrolidinium ionic liquids (ILs) were measured using (1)H pulse field gradient (PFG) NMR spectroscopy over various temperatures. These NMR diffusion results were combined with previously measured rotational diffusion coefficients (D(R)) obtained from (14)N NMR relaxation measurements for the same ILs (Alam, T. M.; et al. J. Phys. Chem. A 2011, 115, 4307- 4316). The D(T)/D(R) ratio was then used to estimate the effective hydrodynamic radius and corresponding volumes without the need to directly measure the viscosities of the ILs. The generality, validity, and performance of using this D(T)/D(R) ratio is discussed and compared to the effective hydrodynamic volumes obtained using classic D(T)/viscosity and D(R)/viscosity relationships. The temperature variation observed for the molecular volumes obtained using the D(T)/D(R) ratio is argued to be a signature for the breakdown or decoupling of the Stokes-Einstein and Stoke-Einstein-Debye relationships in these neat IL systems, consistent with recent molecular dynamic simulations. PMID:23327476

  9. Pyrrolidinium-based ionic liquids doped with lithium salts: how does Li(+) coordination affect its diffusivity?


    Castiglione, Franca; Famulari, Antonino; Raos, Guido; Meille, Stefano V; Mele, Andrea; Appetecchi, Giovanni Battista; Passerini, Stefano


    We present the characterization of LiX-doped room-temperature ionic liquids (ILs) based on the N-butyl-N-methyl pyrrolidinium (PYR14) cation with two fluorinated anions: (trifluoromethanesulfonyl)-(nonafluorobutanesulfonyl)imide (X?IM14) and bis(pentafluoroethanesulfonyl)imide (X?BETI). The new data are also compared with previous results on PYR14TFSI (bis(trifluoromethanesulfonyl)imide). Their local organization has been investigated via NMR nuclear Overhauser effect (NOE) experiments for {(1)H-(19)F} and {(1)H-(7)Li} that give us details on PYR14(+)/X(-) and PYR14(+)/Li(+) contacts. We confirm the presence of [Li(X)2](-) coordinated species in all systems. The long-range, intermolecular NOEs have been detected and provide information on the ions' organization beyond the first solvation sphere. The ionic conductivity, viscosity and self-diffusion coefficients of the ionic mixtures have also been measured. The activation energies for the diffusion of the individual ions and for the fluidity are compared with those for the pure ILs. Finally, density functional calculations on [Li(BETI)2](-), [Li(IM14)2](-), and [Li(TFSI)2](-) complexes demonstrate that the minimum energy structures for all systems correspond to a tetrahedral coordination of the Li-ion by four oxygen atoms of the anions. Assuming very simple key steps for the Li(+) diffusion process (i.e., the concerted breaking and formation of Li-O bonds or the rearrangement around a tetrahedrally coordinated Li(+)), we calculate activation barriers that agree well with the experimental results (approximately 46 kJ/mol, in all systems). PMID:25368963

  10. Stable, High-Efficiency Pyrrolidinium-Based Electrolyte for Solid-State Dye-Sensitized Solar Cells.


    He, Tong; Wang, Ye Feng; Zeng, Jing Hui


    We synthesized a series of pyrrolidinium based dicationic ionic crystals with high melting point and good thermal stability. Research on the crystal structure shows that there are ordered three-dimensional ionic channels in these crystals which is favorable for the ionic conductor to achieve high conductivity and diffusion coefficient. These ionic crystals are applied to electrolyte as matrix in dye sensitized solar cells, and the influence of crystal structure (including the alkylene chain separating two pyrrolidinium rings and anion) versus the device performances are studied by steady-state voltammography, current-voltage trace, and electrochemical impedance spectroscopy. As the solid state electrolyte, an optimized efficiency of 6.02% have achieved under full sunlight irradiation using ionic crystal [C6BEP][TFSI]2. And the device based on this solid electrolyte shows the excellent long-term stability, maintaining 92% of the initial efficiency after 960 h. This study elucidates fundamental the structure of dicationic crystal and provide useful clues for further improvement of solid-state electrolytes in DSSC. PMID:26336080

  11. Crystal structure of [(2S,3R)-3-hy-droxy-3-phenyl-butan-2-yl]pyrrolidinium chloride.


    Kandhaswamy, Abirami; Meena, K S; Deepa, S; Murugavel, S


    In the title mol-ecular salt, C14H22NO(+)Cl(-), the pyrrolidinium ring adopts a twisted conformation about one of the N-C bonds. It is oriented at a dihedral angle of 42.0?(1) with respect to the benzene ring. The torsion angle for the central N-C-C-Car (ar = aromatic) linkage is 163.74?(15). In the crystal, the components are linked via N-H?Cl and O-H?Cl hydrogen bonds, forming zigzig chains along the b-axis direction. These chains are connected along the c axis by very weak C-H?? inter-actions, forming a two-dimensional supra-molecular network. PMID:26594461

  12. A pyrrolidinium nitrate protic ionic liquid-based electrolyte for very low-temperature electrical double-layer capacitors.


    Anouti, Mrim; Timperman, Laure


    This study describes the use of the pyrrolidinium nitrate ([Pyrr][NO3]) protic ionic liquid (PIL) in a mixture with gamma butyrolactone (?-BL) as an electrolyte for carbon-based supercapacitors with an operating voltage of 2.0 V and at very low temperature. Thermal and transport properties of this electrolyte were firstly evaluated from -40 C to 80 C. The evolution of conductivity with the addition of ?-BL rendered it possible to determine the optimal composition for electrochemical application, with a molar fraction of ?-BL of 0.6. This mixture shows a Newtonian behavior with a low viscosity value of 5 mPa s at 25 C, and exhibits high conductivity values of up to 65 mS cm(-1) at 80 C. At the same time, exceptional residual conductivity was measured for this composition at -40 C (9 mS cm(-1)), thanks to the superionic character of pyrrolidinium nitrate PIL. Electrochemical characterization of this electrolyte demonstrated, at first, a passivation on the aluminum collector, secondly good cycling performances with an activated carbon electrode from 50 C to -40 C with capacitance up to 132 F g(-1) at room temperature and a wide voltage window (2.0 V). Finally at very low temperature (-40 C), this system demonstrates an unprecedented combination of high specific capacitance (up to 117 F g(-1)), and rapid charging-discharging even at high current density, which is very promising for the progress of energy storage systems with environmentally friendly electrolytes at such very low temperatures. PMID:23532057

  13. Crystal structure of [(2S,3R)-3-hy­droxy-3-phenyl­butan-2-yl]pyrrolidinium chloride

    PubMed Central

    Kandhaswamy, Abirami; Meena, K.S.; Deepa, S.; Murugavel, S.


    In the title mol­ecular salt, C14H22NO+·Cl−, the pyrrolidinium ring adopts a twisted conformation about one of the N—C bonds. It is oriented at a dihedral angle of 42.0 (1)° with respect to the benzene ring. The torsion angle for the central N—C—C—Car (ar = aromatic) linkage is 163.74 (15)°. In the crystal, the components are linked via N—H⋯Cl and O—H⋯Cl hydrogen bonds, forming zigzig chains along the b-axis direction. These chains are connected along the c axis by very weak C—H⋯π inter­actions, forming a two-dimensional supra­molecular network. PMID:26594461

  14. Rotational and Translational Dynamics of Rhodamine 6G in a Pyrrolidinium Ionic Liquid: A Combined Time-Resolved Fluorescence Anisotropy Decay and NMR Study

    SciTech Connect

    Guo, Jianchang; Han, Kee Sung; Mahurin, Shannon Mark; Baker, Gary A; Hillesheim, Patrick C; Dai, Sheng; Hagaman, Edward {Ed} W; Shaw, Robert W


    NMR spectroscopy and time-resolved fluorescence anisotropy decay (TRFAD) are two of the most commonly used methods to study solute-solvent interactions. However, only a few studies have been reported to date using a combined NMR and TRFAD approach to systematically investigate the overall picture of diffusional and rotational dynamics of both the solute and solvent. In this paper, we combined NMR and TRFAD to probe fluorescent rhodamine dyes in a pyrrolidinium-based room temperature ionic liquid (RTIL), an emergent environmentally-friendly solvent type used in several energy-related applications. A specific interaction of the R6G cation and [Tf2N]- anion was identified, resulting in near-stick boundary condition rotation of R6G in this RTIL. The diffusional rates of the R6G solute and [C4mpyr][Tf2N] solvent derived from 1H NMR suggest the rates are proportional to their corresponding hydrodynamic radii. The 1H and 13C NMR studies of self-rotational dynamics of [C4mpyr][Tf2N] showed that the self-rotational correlation time of [C4mpyr]+ is 47 2 ps at 300 K. At the same temperature, we find that the correlation time for N-CH3 rotation in [C4mpyr]+ is 77 2 ps, comparable to overall molecular reorientation. This slow motion is attributed to properties of the cation structure.

  15. Structure and properties of Li-ion conducting polymer gel electrolytes based on ionic liquids of the pyrrolidinium cation and the bis(trifluoromethanesulfonyl)imide anion

    NASA Astrophysics Data System (ADS)

    Pitawala, Jagath; Navarra, Maria Assunta; Scrosati, Bruno; Jacobsson, Per; Matic, Aleksandar


    We have investigated the structure and physical properties of Li-ion conducting polymer gel electrolytes functionalized with ionic liquid/lithium salt mixtures. The membranes are based on poly(vinylidene fluoride-co-hexafluoropropylene) copolymer, PVdF-HFP, and two ionic liquids: pyrrolidinium cations, N-butyl-N-methylpyrrolidinium (PyR14+), N-butyl-N-ethylpyrrolidinium (PyR24+), and bis(trifluoromethanesulfonyl)imide anion (TFSI). The ionic liquids where doped with 0.2 mol kg--1 LiTFSI. The resulting membranes are freestanding, flexible, and nonvolatile. The structure of the polymer and the interactions between the polymer and the ionic liquid electrolyte have been studied using Raman spectroscopy. The ionic conductivity of the membranes has been studied using dielectric spectroscopy whereas the thermal properties were investigated using differential scanning caloriometry (DSC). These results show that there is a weak, but noticeable, influence on the physical properties of the ionic liquid by the confinement in the membrane. We observe a change in the Li-ion coordination, conformation of the anion, the fragility and a slight increase of the glass transition temperatures for IL/LiTFSI mixtures in the membranes compared to the neat mixtures. The effect can be related to the confinement of the liquid in the membrane and/or to interactions with the PVdF-HFP polymer matrix where the crystallinity is decreased compared to the starting polymer powder.

  16. Homogeneous lithium electrodeposition with pyrrolidinium-based ionic liquid electrolytes.


    Grande, Lorenzo; von Zamory, Jan; Koch, Stephan L; Kalhoff, Julian; Paillard, Elie; Passerini, Stefano


    In this study, we report on the electroplating and stripping of lithium in two ionic liquid (IL) based electrolytes, namely N-butyl-N-methylpyrrolidinium bis(fluorosulfonyl) imide (Pyr14FSI) and N-butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (Pyr14TFSI), and mixtures thereof, both on nickel and lithium electrodes. An improved method to evaluate the Li cycling efficiency confirmed that homogeneous electroplating (and stripping) of Li is possible with TFSI-based ILs. Moreover, the presence of native surface features on lithium, directly observable via scanning electron microscope imaging, was used to demonstrate the enhanced electrolyte interphase (SEI)-forming ability, that is, fast cathodic reactivity of this class of electrolytes and the suppressed dendrite growth. Finally, the induced inhomogeneous deposition enabled us to witness the SEI cracking and revealed previously unreported bundled Li fibers below the pre-existing SEI and nonrod-shaped protuberances resulting from Li extrusion. PMID:25714124

  17. Bulk and liquid-vapor interface of pyrrolidinium-based ionic liquids: a molecular simulation study.


    Paredes, Xavier; Fernndez, Josefa; Pdua, Aglio A H; Malfreyt, Patrice; Malberg, Friedrich; Kirchner, Barbara; Pensado, Alfonso S


    Using molecular dynamics simulations, we have studied the structure of three 1-butyl-1-methylpyrrolidinium ionic liquids whose anions are triflate, bis(trifluoromethanesulfonyl)imide, and tris(pentafluoroethyl)trifluorophosphate. The structure of the bulk phase of the three ionic liquids has been interpreted using radial and spatial distribution functions and structure factors that allows us to characterize the morphology of the polar and nonpolar domains present in this family of liquids. The size of the polar regions depends on the anion size, whereas the morphology of the nonpolar domains is anion-independent. Furthermore, the surface ordering properties of the ionic liquids and charge and density profiles were also studied using molecular simulations. The surface tension of the liquid-vapor interfaces of these ionic liquids was also predicted from our molecular simulations. In addition, microscopic structural analysis of orientational ordering at the interface and density profiles along the direction normal to the interface suggest that the alkyl chains of the cation tend to protrude toward the vacuum, and the presence of the interface leads to a strong organization of the liquid phase in the region close to the interface. In the interfacial area, the polar regions of the ionic liquids are more structured than those in the bulk phase, whereas the opposite behavior is observed for the nonpolar regions. PMID:24383956

  18. Effect of pyrrolidinium based ionic liquid on the channel form of gramicidin in lipid vesicles.


    Singh, Upendra Kumar; Dohare, Neeraj; Mishra, Prabhash; Singh, Prashant; Bohidar, Himadri B; Patel, Rajan


    The present work is focused on the interaction between membrane bound gramicidin and 1-butyl-1-methyl-2-oxopyrrolidinium bromide (BMOP) ionic liquid. Ionic liquids (ILs) are solvents that are often liquid at room temperature and composed of organic cation and appropriate anion. The gramicidin peptide forms prototypical ion channels for cations, which have been extensively used to study the organization, dynamics, and function of membrane spanning channels. The interaction was studied by circular dichroism, steady state, time-resolved fluorescence spectroscopy in combination with dynamic surface tension and field emission scanning electron microscopic methods (FESEM). The results obtained from circular dichroism shows that the BMOP interacts with the channel form of gramicidin in lipid vesicle without any considerable effect on its conformation. The Red-edge excitation shift (REES) also supported the above findings. In addition, the fluorescence studies suggested that BMOP makes ground state complex with ion channel, which was further supported by time resolved measurements. Furthermore, dynamic surface tension analysis shows the faster adsorption of BMOP with membrane bound gramicidin at the air-water interface. Additionally, FESEM results indicated that BMOP forms a film around the membrane bound gramicidin at higher concentration. These results are potentially useful to analyze the effect of ionic liquids on the behaviour of membrane proteins. PMID:26025771

  19. Influence of solute charge and pyrrolidinium ionic liquid alkyl chain length on probe rotational reorientation dynamics.


    Guo, Jianchang; Mahurin, Shannon M; Baker, Gary A; Hillesheim, Patrick C; Dai, Sheng; Shaw, Robert W


    In recent years, the effect of molecular charge on the rotational dynamics of probe solutes in room-temperature ionic liquids (RTILs) has been a subject of growing interest. For the purpose of extending our understanding of charged solute behavior within RTILs, we have studied the rotational dynamics of three illustrative xanthene fluorescent probes within a series of N-alkylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([Cnmpyr][Tf2N]) RTILs with different n-alkyl chain lengths (n = 3, 4, 6, 8, or 10) using time-resolved fluorescence anisotropy decay. The rotational dynamics of the neutral probe rhodamine B (RhB) dye lies between the stick and slip boundary conditions due to the influence of specific hydrogen bonding interactions. The rotation of the negatively charged sulforhodamine 640 (SR640) is slower than that of its positively charged counterpart rhodamine 6G (R6G). An analysis based upon Stokes-Einstein-Debye hydrodynamics indicates that SR640 adheres to stick boundary conditions due to specific interactions, whereas the faster rotation of R6G is attributed to weaker electrostatic interactions. No significant dependence of the rotational dynamics on the solvent alkyl chain length was observed for any of the three dyes, suggesting that the specific interactions between dyes and RTILs are relatively independent of this solvent parameter. PMID:24401127

  20. Photodetachment and electron reactivity in 1-methyl-1-butyl-pyrrolidinium bis(trifluoromethylsulfonyl)amide

    SciTech Connect

    Molins i Domenech, Francesc; FitzPatrick, Benjamin; Healy, Andrew T.; Blank, David A.


    The transient absorption spectrum in the range 500 nm-1000 nm was measured with ultrafast time resolution on a flowing neat, aliphatic, room-temperature ionic liquid following anion photodetachment. In this region the spectrum was shown to be a combination of absorption from the electron and the hole. Spectrally-resolved electron quenching determined a bimodal shape for the hole spectrum in agreement with recent computational predictions on a smaller aliphatic ionic liquid [Margulis et al., J. Am. Chem. Soc. 133, 20186 (2011)]. For time delays beyond 15 ps, spectral evolution qualitatively agrees with recent radiolysis experiments [Wishart et al., Faraday Discuss. 154, 353 (2012)]. However, the shape of the spectrum is different, reflecting the contrast in ionization energy between the two methods. Previously unobserved reactivity of the electron was found with a time constant of 300 fs. The results demonstrate solvent control of the rate coefficient for reaction between the electron and proton, with a rapid decline in the rate within the first picosecond.

  1. Communication: X-ray Scattering from Ionic Liquids with Pyrrolidinium Cations

    SciTech Connect

    C Santos; N Murthy; G Baker; E Castner


    We report the structure functions obtained from x-ray scattering experiments on a series of four homologous ionic liquids. The ionic liquids are 1-alkyl-1-methylpyrrolidinium cations paired with the bis(trifluoromethylsulfonyl)amide anion, with alkyl chain lengths of n = 4, 6, 8, and 10. The structure functions display two intense diffraction peaks for values of the scattering vector q in the range from 0.6 to 1.5 {angstrom}{sup -1} for all samples. Both diffraction peaks shift to lower values of q for increasing temperature. First sharp diffraction peaks are observed in the structure functions for q < 0.5 {angstrom}{sup -1} for liquids with n = 6, 8, and 10.

  2. Influence of Solute Charge and Pyrrolidinium Ionic Liquid Alkyl Chain Length on Probe Rotational Reorientation Dynamics

    SciTech Connect

    Guo, Jianchang; Mahurin, Shannon Mark; Baker, Gary A; Hillesheim, Patrick C; Dai, Sheng; Shaw, Robert W


    In recent years, the effect of molecular charge on the rotational dynamics of probe solutes in room temperature ionic liquids (RTILs) has been a subject of growing interest. For the purpose of extending our understanding of charged solute behavior within RTILs, we have studied the rotational dynamics of three illustrative xanthene fluorescent probes within a series of N-alkylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([Cnmpyr][Tf2N]) RTILs with different n-alkyl chain lengths (n = 3, 4, 6, 8, or 10) using time-resolved fluorescence anisotropy decay. The rotational dynamics of the neutral probe rhodamine B dye lies between the stick and slip boundary conditions due to the influence of specific hydrogen bonding interactions. The rotation of the negatively-charged sulforhodamine 640 is slower than that of its positively-charged counterpart rhodamine 6G. An analysis based upon Stokes-Einstein-Debye hydrodynamics indicates that SR640 adheres to stick boundary conditions due to specific interactions, whereas the faster rotation of R6G is attributed to weaker electrostatic interactions. No dependence of the rotational dynamics on the solvent alkyl chain length was observed for any of the three dyes, suggesting that the specific interactions between dyes and RTILs are independent of this solvent parameter.

  3. Structure, ion transport, and relaxation dynamics of polyethylene oxide/poly (vinylidene fluoride co-hexafluoropropylene)—lithium bis(trifluoromethane sulfonyl) imide blend polymer electrolyte embedded with ionic liquid

    NASA Astrophysics Data System (ADS)

    Das, S.; Ghosh, A.


    We have studied structure, ion transport, and relaxation dynamics in polyethylene oxide/poly (vinylidene fluoride-hexafluoropropylene)-lithium bis(trifluoromethane)sulfonimide blend polymer electrolytes embedded with 1-propyl-3-methyleimidazoliuum bis(trifluromethyle-sulfonyl)imide ionic liquid. Structural property and ion-polymer interaction of polymer electrolytes have been studied using X-ray diffraction and Raman spectroscopy. The addition of ionic liquid decreases glass transition temperature and reduces crystalline phase in the polymer matrix. It is also observed that surface becomes smooth with increase of ionic liquid content. The temperature dependence of the Li ion conductivity follows Vogel-Tammann-Fulcher type behaviour when a sufficient amount of ionic liquid is added to polymer matrix. The electric modulus has been studied using Havriliak-Negami function for the understanding of ion dynamics. The modulus data have been analyzed using non-exponential Kohlrausch-Williams-Watts function. It is observed that the non-exponential parameter β is quite lower than unity, suggesting existence of a non-exponential relaxation. The temperature dependence of the relaxation time also follows Vogel-Tammann-Fulcher relation for compositions with higher ionic liquid content.

  4. Simultaneous separation of acidic and basic proteins using gemini pyrrolidinium surfactants and hexafluoroisopropanol as dynamic coating additives in capillary electrophoresis.


    Tian, Yu; Li, Yunfang; Mei, Jie; Cai, Bo; Dong, Jinfeng; Shi, Zhiguo; Xiao, Yuxiu


    The separation of acidic and basic proteins using CE has been limited in part due to the adsorption of proteins onto the capillary wall. In this work, the efficient control of EOF and the simultaneous separation of acidic and basic proteins are achieved by use of C18-4-C18PB as a dynamic coating additive, which is a representative surfactant for 1,1'-(butane-1,s-alkyl)bis(1-alkylpyrrolidinium) bromide (Cn-4-CnPB, n=10, 12, 14, 16 and 18). C18-4-C18PB exhibits a powerful capability in the reversal of EOF, and a low concentration even less than 0.001 mM is sufficient to reverse EOF at the tested pH values (3.0-9.0). Baseline separation of eight proteins with sharp peaks and high efficiencies (54,000-297,000 plates/m) is obtained with 30 mM NaH2PO4 buffer (pH 5.0) containing 4 mM C18-4-C18PB. At the same buffer condition, the Cn-4-CnPB with shorter alkyl chain (n=10, 12, 14, 16) cannot achieve the same effective protein separation as C18-4-C18PB. However, the combined use of small amounts (?0.5%, v/v) of hexafluoroisopropanol (HFIP) and Cn-4-CnPB (n=10, 12, 14, 16) as additives can completely separate all eight proteins with high efficiencies of 81,000-318,000 plates/m. The RSDs of migration time are less than 0.80% and 5.84% for run-to-run and day-to-day assays (n=5), respectively, and the protein recoveries are larger than 90.15%. To the best of our knowledge, this is the first report on the simultaneous separation of acidic and basic proteins using Cn-4-CnPB surfactants or Cn-4-CnPB surfactants combined with HFIP as dynamic coating additives. PMID:26300480

  5. Bucky gel of multiwalled carbon nanotubes as electrodes for high performance, flexible electric double layer capacitors

    NASA Astrophysics Data System (ADS)

    Singh, Manoj K.; Kumar, Yogesh; Hashmi, S. A.


    We report the preparation of a gelled form of multiwalled carbon nanotubes (MWCNTs) with an ionic liquid 1-butyl-1-methyl pyrrolidinium bis(trifluoromethane sulfonyl)imide (BMPTFSI)), referred to as bucky gel, to be used as binderless electrodes in electrical double layer capacitors (EDLCs). The characteristics of gelled MWCNTs are compared with pristine MWCNTs using transmission electron microscopy, x-ray diffraction and Raman studies. A gel polymer electrolyte film consisting of a blend of poly(vinylidene fluoride-co-hexafluoropropylene) and BMPTFSI, exhibiting a room temperature ionic conductivity of 1.5 10-3 S cm-1, shows its suitability as an electrolyte/separator in flexible EDLCs. The performance of EDLCs, assembled with bucky gel electrodes, using impedance spectroscopy, cyclic voltammetry and charge-discharge analyses, are compared with those fabricated with pristine MWCNT-electrodes. An improvement in specific capacitance (from 19.6 to 51.3 F g-1) is noted when pristine MWCNTs are replaced by gelled MWCNT-binderless electrodes. Although the rate performance of the EDLCs with gelled MWCNT-electrodes is reduced, the pulse power of the device is sufficiently high (10.5 kW kg-1). The gelled electrodes offer improvements in energy and power densities from 2.8 to 8.0 Wh kg-1 and 2.0 to 4.7 kW kg-1, respectively. Studies indicate that the gel formation of MWCNTs with ionic liquid is an excellent route to obtain high-performance EDLCs.

  6. Azepanium-based ionic liquids as green electrolytes for high voltage supercapacitors

    NASA Astrophysics Data System (ADS)

    Pohlmann, S.; Olyschlger, T.; Goodrich, P.; Alvarez Vicente, J.; Jacquemin, J.; Balducci, A.


    This work provides a first-time-study of Azepanium-based ionic liquids (ILs) as electrolyte components for electrochemical double layer capacitors (EDLCs). Herein, two Azepanium-based ILs, namely N-methyl, N-butyl-azepanium bis(trifluoromethanesulfonyl)imide (Azp14TFSI) and N-methyl, N-hexyl-azepanium bis(trifluoromethanesulfonyl)imide (Azp16TFSI) were compared with the established IL N-butyl, N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (Pyr14TFSI) in terms of viscosity, conductivity, thermal stability and electrochemical behavior in EDLC systems. The ILs' operative potentials were found to be comparable, leading to operative voltages up to 3.5 V without significant electrolyte degradation.


    SciTech Connect

    Fox, E.


    Ionic liquids are often cited for their excellent thermal stability, a key property for their use as solvents and in the chemical processing of biofuels. However, there has been little supporting data on the long term aging effect of temperature on these materials. Imizadolium, quaternary ammonium, pyridinium, and pyrrolidnium-based ionic liquids with the bis(trifluoromethylsulfonyl)imide and bis(perfluoroethylsulfonyl)imide anions were aged for 2520 hours (15 weeks) at 200�C in air to determine the effects of an oxidizing environment on their chemical structure and thermal stability over time. It was found that the minor changes in the cation chemistry could greatly affect the properties of the ILs over time.

  8. FTIR and Raman Study of the LixTiyMn1-yO2 (y = 0, 0.11) Cathodes in Methylpropyl Pyrrolidinium Bis(fluoro-sulfonyl)imide, LiTFSI Electrolyte

    SciTech Connect

    Hardwick, L.J.; Lucas, I.T.; Doeff, M.M.; Kostecki, R.; Saint, J.A.


    This work demonstrates the protective effect of partial titanium substitution in Li{sub x}Ti{sub 0.11}Mn{sub 0.89}O{sub 2} against surface decomposition in room-temperature ionic liquid (RTILs) cells. Raman microscopy and reflectance Fourier transform IR (FTIR) spectroscopy were used to analyze electrodes recovered from cycled Li/Li{sub x}Ti{sub y}Mn{sub 1-y}O{sub 2} (y=0, 0.11) cells containing the 0.5 mol/kg LiTFSI in P{sub 13}FSI RTIL electrolyte. [TFSI=bis(trifluoromethanesulfonyl)imide.] Raman and FTIR spectra of cycled Li{sub x}MnO{sub 2} cathodes showed many distinct bands that can be attributed to both the electrolyte and electrode decomposition products. The thickness of the amorphous porous layer on the Li{sub x}MnO{sub 2} cathode increased during cycling. The surface degradation of Li{sub x}MnO{sub 2} and precipitation of electrolyte decomposition products contributed to the film growth. Improved cycling behavior was observed in cells containing Li{sub x}Ti{sub 0.11}Mn{sub 0.89}O{sub 2}, yet Raman spectroscopy also showed possible surface degradation. The FTIR spectra of cycled Li{sub x}MnO{sub 2} and Li{sub x}Ti{sub 0.11}Mn{sub 0.89}O{sub 2} cathodes displayed bands characteristic for LiSO{sub 3}CF{sub 3} and Li{sub 2}NSO{sub 2}CF{sub 3}, which originate from the reaction of the TFSI anion with traces of water present in the cell.

  9. Electrochemical performance of 0.5Li2MnO3-0.5Li(Mn0.375Ni0.375Co0.25)O2 composite cathode in pyrrolidinium-based ionic liquid electrolytes

    NASA Astrophysics Data System (ADS)

    Patra, Jagabandhu; Dahiya, Prem Prakash; Tseng, Chung-Jen; Fang, Jason; Lin, Yu-Wei; Basu, S.; Majumder, S. B.; Chang, Jeng-Kuei


    High-energy-density 0.5Li2MnO3-0.5Li(Mn0.375Ni0.375Co0.25)O2 composite cathodes for lithium rechargeable batteries are synthesized using an auto-combustion method. The electrode charge-discharge properties are studied at 25 and 50 °C in Li+-containing N-butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (BMP-TFSI) and N-propyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PMP-TFSI) ionic liquid (IL) electrolytes. The IL electrolytes have a high decomposition temperature (∼400 °C) and thus are ideal for high-safety applications. Compared to Li+/BMP-TFSI IL, Li+/PMP-TFSI IL exhibits higher ionic conductivity and lower viscosity. As a result, the composite cathode shows superior electrochemical performance in Li+/PMP-TFSI IL electrolyte. With the increase in cell temperature from 25 to 50 °C, the maximum capacities and rate capabilities of both IL cells improve significantly. Thus at 50 °C, discharge capacities of 304 mAh g-1 (@10 mA g-1) and 223 mAh g-1 (@100 mA g-1) are obtained for the Li+/PMP-TFSI cell. These capacities are superior to those for a control cell made with the same composite cathode and a conventional organic electrolyte. At elevated temperature, the cyclability of the composite cathode in the IL electrolytes is markedly higher than that obtained in a conventional organic electrolyte.

  10. Bicyclic imidazolium ionic liquids as potential electrolytes for rechargeable lithium ion batteries

    SciTech Connect

    Liao, Chen; Shao, Nan; Bell, Jason R; Guo, Bingkun; Luo, Huimin; Jiang, Deen; Dai, Sheng


    A bicyclic imidazolium ionic liquids, 1-ethyl-2,3-trimethyleneimidazolium bis(tri fluoromethane sulfonyl)imide ([ETMIm][TFSI]), and reference imidazolium compounds, 1-ethyl-3-methylimidazolium bis(trifluoromethane sulfonyl)imide ([EMIm][TFSI]) and 1, 2-dimethyl-3-butylimidazolium bis(trifluoromethane sulfonyl)imide ([DMBIm][TFSI]), were synthesized and investigated as solvents for lithium ion batteries. Although the alkylation at the C-2 position of the imidazolium ring does not affect the thermal stability of the ionic liquids, with or without the presence of 0.5 molar lithium bis(trifluoromethane sulfonyl)imide (LiTFSI), the stereochemical structure of the molecules has shown profound influences on the electrochemical properties of the corresponding ionic liquids. [ETMIm][TFSI] shows better reduction stability than do [EMIm][TFSI] and [DMBIm][TFSI], as confirmed by both linear sweep voltammery (LSV) and theoretical calculation. The Li||Li cell impedance of 0.5M LiTFSI/[ETMIm][TFSI] is stabilized, whereas that of 0.5M LiTFSI/[DMBIm][TFSI] is still fluctuating after 20 hours, indicating a relatively stable solid electrolyte interphase (SEI) is formed in the former. Furthermore, the Li||graphite half-cell based on 0.5M LiTFSI/[BTMIm][TFSI] exhibits reversible capacity of 250mAh g-1 and 70mAh g-1 at 25 C, which increases to 330 mAh g-1 and 250 mAh g-1 at 50 C, under the current rate of C/20 and C/10, respectively. For comparison, the Li||graphite half-cell based on 0.5M LiTFSI/[DMBIm][TFSI] exhibits poor capacity retention under the same current rate at both temperatures.

  11. Non-aggregated Zn(ii)octa(2,6-diphenylphenoxy) phthalocyanine as a hole transporting material for efficient perovskite solar cells.


    Javier Ramos, F; Ince, M; Urbani, M; Abate, Antonio; Grtzel, M; Ahmad, Shahzada; Torres, T; Nazeeruddin, Mohammad Khaja


    A non-aggregated Zn(ii)octa(2,6-diphenylphenoxy) phthalocyanine (coded as TT80) has been used as a hole-transporting material for perovskite solar cells. The cells were fabricated under three different configurations by changing the uptake solvent (chlorobenzene or toluene) and incorporating additives (bis(trifluoromethane) sulfonimide lithium salt (LiTFSI) and 4-tert-butylpyridine (TBP). A power conversion efficiency of 6.7% (AM1.5G standard conditions) was achieved for the best cell under optimized configuration. PMID:25815796

  12. Lithium-sulfur batteries based on nitrogen-doped carbon and ionic liquid electrolyte

    SciTech Connect

    Sun, Xiao-Guang; Wang, Xiqing; Mayes, Richard T; Dai, Sheng


    Nitrogen-doped mesoporous carbon (NC) and sulfur were used to prepare an NC/S composite cathode, which was evaluated in an ionic liquid electrolyte of 0.5 M lithium bis(trifluoromethane sulfonyl)imide (LiTFSI) in methylpropylpyrrolidinium bis(trifluoromethane sulfonyl)imide (MPPY.TFSI) by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and cycle testing. To facilitate the comparison, a C/S composite based on activated carbon (AC) without nitrogen doping was also fabricated under the same conditions as those for the NC/S composite. Compared with the AC/S composite, the NC/S composite showed enhanced activity toward sulfur reduction, as evidenced by the early onset sulfur reduction potential, higher redox current density in the CV test, and faster charge transfer kinetics as indicated by EIS measurement. At room temperature under a current density of 84 mA g-1 (C/20), the battery based on the NC/S composite exhibited higher discharge potential and an initial capacity of 1420 mAh g-1 whereas that based on the AC/S composite showed lower discharge potential and an initial capacity of 1120 mAh g-1. Both batteries showed similar capacity fading with cycling due to the intrinsic polysulfide solubility and the polysulfide shuttle mechanism; the capacity fading can be improved by further modification of the cathode.

  13. Synthesis of organic (trimethylsilyl)chalcogenolate salts Cat[TMS-E] (E = S, Se, Te): the methylcarbonate anion as a desilylating agent.


    Finger, Lars H; Scheibe, Benjamin; Sundermeyer, Jrg


    A high-yield synthesis of the class of (trimethylsilyl)chalcogenolate organic salts [Cat][TMS-E] (E = S, Se, Te; Cat = BMPyr, DMPyr, NMe4, nBu3MeP) is presented. The title compounds have been prepared by the strictly aprotic reaction between the respective bis(trimethylsilyl)chalcogenide (TMS2E) and methylcarbonate ionic liquids (ILs). This constitutes a novel reaction behavior of methylcarbonate ILs, acting as a nucleophilic desilylating agent and a Lewis base instead of as a Brnsted base. Thus prepared silylchalcogenolate salts represent an activated form of the multifunctional TMS2E reactant series. Pyrrolidinium TMS-S salts have proven to be excellent precursors for the synthesis of pyrrolidinium hexasulfides. The scope of the desilylation reaction can be extended to other silyl-bearing synthons such as (trimethylsilyl)azide and (trimethylsilyl)cyanide. PMID:26371537

  14. A new family of ionic liquids based on N,N-dialkyl-3-azabicyclo[3.2.2]nonanium cations: organic plastic crystal behaviour and highly reversible lithium metal electrodeposition.


    Rther, Thomas; Huang, Junhua; Hollenkamp, Anthony F


    A new family of ionic liquids based on N,N-dialkyl-3-azabicyclo[3.2.2]nonanium cations exhibits wide electrochemical windows, excellent lithium deposition-stripping behaviour and plastic crystal properties and therefore these cation structures, which are extensions from pyrrolidinium- and piperidinium-based cations, complement a set of related structures for a systematic study on the physicochemical properties of ionic liquids. PMID:18060150

  15. Structural effects of ionic liquids on microalgal growth inhibition and microbial degradation.


    Pham, Thi Phuong Thuy; Cho, Chul-Woong; Yun, Yeoung-Sang


    In the present study, we investigated structural effects of various ionic liquids (ILs) on microalgal growth inhibition and microbial biodegradability. For this, we tested pyridinium- and pyrrolidinium-based ILs with various alkyl chain lengths and bromide anion, and compared the toxicological effects with log EC50 values of imidazolium-based IL with the same alkyl chains and anion from literature. Comparing determined EC50 values of cationic moieties with the same alkyl chain length, pyridinium-based ILs were found to be slightly more toxic towards the freshwater green alga, Pseudokirchneriella subcapitata, than a series of pyrrolidinium and imidazolium except to 1-octyl-3-methylimidazolium bromide. Concerning the biodegradation study of 12 ILs using the activated sludge microorganisms, the results showed that the pyridinium derivatives except to 1-propyl-3-methylpyridinium cation were degraded. Whereas in case of imidazolium- and pyrrolidinium-based compounds, only n-hexyl and n-octyl substituted cations were fully degraded but no significant biodegradation was observed for the short chains (three and four alkyl chains). PMID:26330315

  16. Development and Characterization of Poly(1-vinylpyrrolidone-co-vinyl acetate) Copolymer Based Polymer Electrolytes

    PubMed Central

    Sa'adun, Nurul Nadiah; Subramaniam, Ramesh; Kasi, Ramesh


    Gel polymer electrolytes (GPEs) are developed using poly(1-vinylpyrrolidone-co-vinyl acetate) [P(VP-co-VAc)] as the host polymer, lithium bis(trifluoromethane) sulfonimide [LiTFSI] as the lithium salt and ionic liquid, and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide [EMImTFSI] by using solution casting technique. The effect of ionic liquid on ionic conductivity is studied and the optimum ionic conductivity at room temperature is found to be 2.14??10?6?S?cm?1 for sample containing 25?wt% of EMImTFSI. The temperature dependence of ionic conductivity from 303?K to 353?K exhibits Arrhenius plot behaviour. The thermal stability of the polymer electrolyte system is studied by using thermogravimetric analysis (TGA) while the structural and morphological properties of the polymer electrolyte is studied by using Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction analysis (XRD), respectively. PMID:25431781

  17. Dynamics and relaxation of charge carriers in poly(methylmethacrylate)-based polymer electrolytes embedded with ionic liquid

    NASA Astrophysics Data System (ADS)

    Pal, P.; Ghosh, A.


    In the present paper, we have studied dynamics and relaxation of the charge carriers in polymethylmethacrylate-lithium bis(trifluoromethane sulfonyl)imide polymer electrolytes embedded with 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ionic liquid. We have analyzed the frequency dependent conductivity spectra using the random free-energy barrier model coupled with the contribution of electrode polarization in the low frequency region. The temperature dependence of ionic conductivity, and relaxation time obtained from the analysis of the spectra exhibits Vogel-Tammann-Fulcher type behavior. The Barton-Nakajima-Namikawa relation is consistent with the results obtained from the random free-energy barrier model. The scaling of ac conductivity spectra has been performed to understand the effect of temperature as well as the composition on the relaxation mechanism. The analysis of the ac conductivity also clearly indicates the existence of a nearly constant loss phenomenon at low temperatures or at high frequencies.

  18. Environmentally-friendly lithium recycling from a spent organic li-ion battery.


    Renault, Stven; Brandell, Daniel; Edstrm, Kristina


    A simple and straightforward method using non-polluting solvents and a single thermal treatment step at moderate temperature was investigated as an environmentally-friendly process to recycle lithium from organic electrode materials for secondary lithium batteries. This method, highly dependent on the choice of electrolyte, gives up to 99% of sustained capacity for the recycled materials used in a second life-cycle battery when compared with the original. The best results were obtained using a dimethyl carbonate/lithium bis(trifluoromethane sulfonyl) imide electrolyte that does not decompose in presence of water. The process implies a thermal decomposition step at a moderate temperature of the extracted organic material into lithium carbonate, which is then used as a lithiation agent for the preparation of fresh electrode material without loss of lithium. PMID:25170568

  19. B?O?-added lithium aluminium germanium phosphate solid electrolyte for Li-O? rechargeable batteries.


    Jadhav, Harsharaj S; Kalubarme, Ramchandra S; Jang, Seong-Yong; Jung, Kyu-Nam; Shin, Kyoung-Hee; Park, Chan-Jin


    B2O3-added Li(1.5)Al(0.5)Ge(1.5)(PO4)3 (LAGP) glass ceramics showing a room temperature ionic conductivity of 0.67 mS cm(-1) have been synthesized by using a melt-quenching method. The prepared glass ceramics are observed to be stable in tetraethylene glycol dimethyl ether containing lithium bis(trifluoromethane) sulfonamide. The augmented conductivity of the B2O3-added LAGP glass ceramic has improved the plateau potential during discharge. Furthermore, the B2O3-added LAGP glass ceramics are successfully employed as a solid electrolyte in a Li-O2 battery to obtain a stable cycling lifetime of up to 15 cycles with the limited capacity protocol. PMID:24953185

  20. Development and characterization of poly(1-vinylpyrrolidone-co-vinyl acetate) copolymer based polymer electrolytes.


    Sa'adun, Nurul Nadiah; Subramaniam, Ramesh; Kasi, Ramesh


    Gel polymer electrolytes (GPEs) are developed using poly(1-vinylpyrrolidone-co-vinyl acetate) [P(VP-co-VAc)] as the host polymer, lithium bis(trifluoromethane) sulfonimide [LiTFSI] as the lithium salt and ionic liquid, and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide [EMImTFSI] by using solution casting technique. The effect of ionic liquid on ionic conductivity is studied and the optimum ionic conductivity at room temperature is found to be 2.14 10(-6) S cm(-1) for sample containing 25 wt% of EMImTFSI. The temperature dependence of ionic conductivity from 303 K to 353 K exhibits Arrhenius plot behaviour. The thermal stability of the polymer electrolyte system is studied by using thermogravimetric analysis (TGA) while the structural and morphological properties of the polymer electrolyte is studied by using Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction analysis (XRD), respectively. PMID:25431781

  1. Studies on the effect of dispersoid(ZrO2) in PVdF-co-HFP based gel polymer electrolytes

    NASA Astrophysics Data System (ADS)

    Sivakumar, M.; Subadevi, R.; Muthupradeepa, R.


    Gel polymer electrolytes containing poly(vinylidenefluoride-co-hexafluoropropylene) (P(VdF-co-HFP)) / Lithium bis(trifluoromethane sulfon)imide (LiTFSI) / mixture of ethylene carbonate and propylene carbonate (EC+PC) with different concendration of ZrO2 has been prepared using the solution casting technique. The conductivity of the prepared electrolyte sample has been determined by AC impedance technique in the range 303-353K. The temperature dependent ionic conductivity plot seems to obey VTF relation. The maximum ionic conductivity value of 4.46 10-3S/cm has been obtained for PVdF-co-HFP(32%) - LiTFSI(8%) - EC+PC (60%) + ZrO2(6wt%) based polymer electrolyte. The surface morphology of the prepared electrolyte sample has been studied using SEM.

  2. Importance of dispersion forces for prediction of thermodynamic and transport properties of some common ionic liquids.


    Izgorodina, Ekaterina I; Golze, Dorothea; Maganti, Radha; Armel, Vanessa; Taige, Maria; Schubert, Thomas J S; MacFarlane, Douglas R


    An extensive study of interaction energies in ion pairs of pyrrolidinium and imidazolium ionic liquids is presented. The Cnmpyr and Cnmim cations with varying alkyl chains from Methyl, Ethyl, n-Propyl to n-Butyl were combined with a wide range of routinely used IL anions such as chloride, bromide, mesylate (CH3SO3 or Mes), tosylate (CH3PhSO3 or Tos), bis(trifluoromethanesulfonyl)amide (NTf2), dicyanamide (N(CN)2 or dca), tetrafluoroborate (BF4) and hexafluorophosphate (PF6). A number of energetically favourable conformations were studied for each cation-anion combination. The interaction energy and its dispersion component of the single ion pairs were calculated using a sophisticated state-of-the-art approach: a second-order of Symmetry Adapted Perturbation Theory (SAPT). A comparison of energetics depending on the cation-anion type, as well as the mode of interaction was performed. Dispersion forces were confirmed to be of importance for the overall stabilisation of ionic liquids contributing from 28 kJ mol(-1) in pyrrolidinium ion pairs to 59 kJ mol(-1) in imidazolium ion pairs. The previously proposed ratio of total interaction energy to dispersion components and melting points was assessed for this set of ionic liquids and was found to correlate with their melting points for the anionic series, producing separate trends for the Cnmim and Cmpyr series of cations. Chlorides, bromides and tetrafluoroborates formed close-to-ideal correlations when both types of cations, Cnmim and Cnmpyr, were combined in the same trend. Correlation of the dispersion component of the interaction energy with transport properties such as conductivity and viscosity was also considered. For imidazolium-based ionic liquids strong linear correlations were obtained, whereas pyrrolidinium ionic liquids appeared to be insensitive to this correlation. PMID:24113510

  3. Highly selective separation of carbon dioxide from nitrogen and methane by nitrile/glycol-difunctionalized ionic liquids in supported ionic liquid membranes (SILMs).


    Hojniak, Sandra D; Silverwood, Ian P; Khan, Asim Laeeq; Vankelecom, Ivo F J; Dehaen, Wim; Kazarian, Sergei G; Binnemans, Koen


    Novel difunctionalized ionic liquids (ILs) containing a triethylene glycol monomethyl ether chain and a nitrile group on a pyrrolidinium or imidazolium cation have been synthesized and incorporated into supported ionic liquid membranes (SILMs). These ILs exhibit ca. 2.3 times higher CO2/N2 and CO2/CH4 gas separation selectivities than analogous ILs functionalized only with a glycol chain. Although the glycol moiety ensures room temperature liquidity of the pyrrolidinium and imidazolium ILs, the two classes of ILs benefit from the presence of a nitrile group in different ways. The difunctionalized pyrrolidinium ILs exhibit an increase in CO2 permeance, whereas the permeances of the contaminant gases rise negligibly, resulting in high gas separation selectivities. In the imidazolium ILs, the presence of a nitrile group does not always increase the CO2 permeance nor does it increase the CO2 solubility, as showed in situ by the ATR-FTIR spectroscopic method. High selectivity of these ILs is caused by the considerably reduced permeances of N2 and CH4, most likely due to the ability of the -CN group to reject the nonpolar contaminant gases. Apart from the CO2 solubility, IL-CO2 interactions and IL swelling were studied with the in situ ATR-FTIR spectroscopy. Different strengths of the IL-CO2 interactions were found to be the major difference between the two classes of ILs. The difunctionalized ILs interacted stronger with CO2 than the glycol-functionalized ILs, as manifested in the smaller bandwidths of the bending mode band of CO2 for the latter. PMID:24895912

  4. Carboxyl-functionalized task-specific ionic liquids for solubilizing metal oxides.


    Nockemann, Peter; Thijs, Ben; Parac-Vogt, Tatjana N; Van Hecke, Kristof; Van Meervelt, Luc; Tinant, Bernard; Hartenbach, Ingo; Schleid, Thomas; Ngan, Vu Thi; Nguyen, Minh Tho; Binnemans, Koen


    Imidazolium, pyridinium, pyrrolidinium, piperidinium, morpholinium, and quaternary ammonium bis(trifluoromethylsulfonyl)imide salts were functionalized with a carboxyl group. These ionic liquids are useful for the selective dissolution of metal oxides and hydroxides. Although these hydrophobic ionic liquids are immiscible with water at room temperature, several of them form a single phase with water at elevated temperatures. Phase separation occurs upon cooling. This thermomorphic behavior has been investigated by (1)H NMR, and it was found that it can be attributed to the temperature-dependent hydration and hydrogen-bond formation of the ionic liquid components. The crystal structures of four ionic liquids and five metal complexes have been determined. PMID:18841931

  5. Unusual phase behaviour of the organic ionic plastic crystal N,N-dimethylpyrrolidinium tetrafluoroborate.


    Pringle, Jennifer M; Adebahr, Josefina; MacFarlane, Douglas R; Forsyth, Maria


    Analysis of N,N-dimethylpyrrolidinium tetrafluoroborate by (1)H and (11)B NMR, Raman spectroscopy and powder XRD shows that this organic ionic plastic crystal material exhibits unusual phase behaviour. (1)H NMR analysis indicates that the mobility of the pyrrolidinium cation decreases when the material is heated into phase I, while the X-ray diffraction pattern changes from a simple, one peak structure in phase II to a more complex pattern in phase I. The possible origins of these unusual transitions are discussed. PMID:20485818

  6. Method for measuring surface temperature


    Baker, Gary A. (Los Alamos, NM); Baker, Sheila N. (Los Alamos, NM); McCleskey, T. Mark (Los Alamos, NM)


    The present invention relates to a method for measuring a surface temperature using is a fluorescent temperature sensor or optical thermometer. The sensor includes a solution of 1,3-bis(1-pyrenyl)propane within a 1-butyl-1-1-methyl pyrrolidinium bis(trifluoromethylsulfonyl)imide ionic liquid solvent. The 1,3-bis(1-pyrenyl)propane remains unassociated when in the ground state while in solution. When subjected to UV light, an excited state is produced that exists in equilibrium with an excimer. The position of the equilibrium between the two excited states is temperature dependent.

  7. Absorption ability and kinetics of a liquid electrolyte in PVDF-HFP copolymer containing or not SiO 2

    NASA Astrophysics Data System (ADS)

    Caillon-Caravanier, M.; Claude-Montigny, B.; Lemordant, D.; Bosser, G.

    Gel polymer electrolytes have been prepared from PVDF-HFP copolymer with various silica contents incorporating Gamma valerolactone (VL) or VL/EC (80/20 in mole) (EC: ethylene carbonate) solutions of lithium bis(trifluoromethane sulfone) imide (LiTFSI). The influence of temperature, salt content and silica addition on the kinetics of absorption and wettability of the copolymer has been investigated. An empirical model, taking into account gel swelling during the absorption allows us to relate, at constant temperature, the wetting time and the volumetric fraction of trapped electrolyte, which is a critical factor for ionic conductivity of the gel. Increasing the silica content in the dry copolymer increases the porosity and consequently the rate of absorption and thus the amount of incorporated liquid phase at saturation. To a lower extent, an increase in the temperature of absorption has the same effects. The prepared gels have good mechanicals properties and conductivities. As an example, a gel of composition: PVDF- HFP/ SiO2/ VL/ EC/ LiTFSI of molar percentages 36/6.7/42/10.5/4.8 exhibits a conductivity of 2.9 mS cm - 1 at 293 K.

  8. Effects of TiO2 addition on ionic conductivity of PVC/PEMA blend based composite polymer electrolyte

    NASA Astrophysics Data System (ADS)

    Subban, R. H. Y.; Sukri, Nursyazwani


    PVC/PEMA blend based polymer electrolytes with lithium bistrifluoromethane sulfonimide (LiN(CF3SO2)2) and PVC/PEMA/(LiN(CF3SO2)2-TiO2 films were prepared by solution cast technique. The sample containing 35 wt. % LiN(CF3SO2)2 exhibited the highest conductivity of 1.75 × 10-5 Scm-1. The conductivity of the sample increased to 2.12 × 10-5 Scm-1 and 4.61 × 10-5 Scm-1 when 4 wt. % and 10 wt. % of titanium dioxide (TiO2) was added to the sample at 65 wt. % PVC/PEMA-35 wt. % LiN(CF3SO2)2 composition respectively. The low increase in conductivity is attributed to two competing factors: increase in crystallinity as accounted by X-Ray diffraction (XRD) and decrease in glass transition temperature as accounted by differential scanning calorimetry (DSC).

  9. Ion conduction in phosphonium-polysiloxane ionomers

    NASA Astrophysics Data System (ADS)

    Liang, Siwei; Hyeok Choi, U.; Runt, James; Colby, Ralph


    Low Tg ionomers with phosphonium cations covalently attached as side chains have potential application in energy conversion and storage devices. For example, alkaline fuel cells rely on membranes that transport hydroxide anions and some advanced batteries rely on membranes transporting fluoride anions. To better understand ion conduction in phosphonium-polysiloxane ionomers, allyl tributyl phosphonium bromide monomer was synthesized and, along with a vinyl ethylene oxide monomer, attached to polymethylhydrosiloxane by hydrosilylation. These ionomers maintain low Tg -74 ^oC with up to 10 mol% phosphonium and are fully water soluble, allowing easy anion exchange and purification. We report dielectric spectroscopy results for these ionomers with a variety of counter-anions. Electrode polarization at low frequencies is analyzed to determine the number density of simultaneously conducting counter ions and their mobility. This analysis reveals higher mobility and lower activation energy for conducting anions that are larger and more diffuse, such as bis(trifluoromethane sulfonyl)imide, contributing to better performance as anion-conducting membranes.

  10. Conductivity and Stability of Photopolymerized Polymer Electrolyte Network

    NASA Astrophysics Data System (ADS)

    Kyu, Thein; He, Ruixuan; Chen, Yu-Ming; Mao, Jialin; Zhu, Yu; Kyu'S Group, , Dr.; Zhu'S Group Collaboration, , Dr.


    A melt-processing window has been identified within the wide isotropic region of the phase diagram of ternary blends consisting of poly (ethylene glycol diacrylate) (PEGDA), tetraethylene glycol dimethyl ether (TEGDME) and lithium bis(trifluoromethane) sulfonamide (LiTFSI). Upon UV-crosslinking of PEGDA in the isotropic window, the polymer electrolyte membrane (PEM) network thus formed is completely transparent and remains in the single phase without undergoing polymerization-induced phase separation or polymerization-induced crystallization. These PEM networks are solid albeit flexible and light-weight with safety and space saving attributes. The ionic conductivity as determined by AC impedance spectroscopy exhibited very high room-temperature ionic conductivity on the order of ~10-3 S/cm in several compositions, viz., 10/45/45, 20/40/40 and 30/35/35 PEGDA/TEGDME/LiTFSI networks. Cyclic voltammetry measurement of these solid-state PEM networks revealed excellent electrochemical stability against lithium reference electrode. The above study has been extended to the anode (graphite) and cathode (LiFePO4) half-cell configurations with lithium as counter electrode. Charge/discharge cycling behavior of these half cells will be discussed. Supported by NSF-DMR 1161070 and University of Akron.

  11. Theoretical study of interactions of a Li(+)(CF3SO2)2N(-) ion pair with CR3(OCR2CR2)nOCR3 (R = H or F).


    Abroshan, Hadi; Dhumal, Nilesh R; Shim, Youngseon; Kim, Hyung J


    Interactions of a lithium bis(trifluoromethane sulfonyl)imide (Li(+)Tf2N(-)) ion pair with oligoethers are investigated via density functional theory (DFT). As a model for polymer electrolytes polyethyleneoxide (PEO) and perfluoropolyether (PFPE), CR3(OCR2CR2)n=1-5OCR3 (R = H or F) is considered. Topographical analysis of the molecular electrostatic potential (MESP) is performed to determine preferential binding sites of Li(+). Our study shows that the MESP value near the oxygen sites of the polymer backbone is more negative for PEO than for PFPE. This result indicates that substitution of hydrogen by fluorine in polyethers leads to reduction in Li(+)-polymer interactions, in concert with the experimental ionic conductivity results. S-O stretching vibrations of Tf2N(-) are calculated for the lithium salt in the presence and absence of electrolytes. The blue and red shifts predicted for S-O stretching are further explained by natural bond orbital analysis and molecular electron density topography. The S-O stretching vibrations can be used as a useful tool to understand the ion pair interactions and thus ion transport phenomena in polymer electrolytes. PMID:26878460

  12. Plasticized Polymer Composite Single-Ion Conductors for Lithium Batteries.


    Zhao, Hui; Asfour, Fadi; Fu, Yanbao; Jia, Zhe; Yuan, Wen; Bai, Ying; Ling, Min; Hu, Heyi; Baker, Gregory; Liu, Gao


    Lithium bis(trifluoromethane) sulfonamide (TFSI) is a promising electrolyte salt in lithium batteries, due to its good conductivity and high dissociation between the lithium cation and its anion. By tethering N-pentane trifluoromethane sulfonamide (C5NHTf), a TFSI analogue molecule, onto the surface of silica nanoparticle as a monolayer coverage should increase the Li(+) transference number to unity since anions bound to particles have reduced mobilities. Silica polymer composite has better mechanical property than that of the pure PEO. Analogously trifluoromethane sulfonic aminoethyl methacrylate (TfMA), a TFSI analogue vinyl monomer, was polymerized on silica nanoparticle surface as a multilayer coverage. Anchored polyelectrolytes to particle surfaces offer multiple sites for anions, and in principle the carrier concentration would increase arbitrarily and approach the carrier concentration of the bulk polyelectrolyte. Monolayer grafted nanoparticles have a lithium content of 1.2 × 10(-3) g Li/g, and multilayer grafted nanoparticles have a lithium content over an order higher at 2 × 10(-2) g Li/g. Electrolytes made from monolayer grafted particles exhibit a weak conductivity dependence on temperature, exhibiting an ionic conductivity in the range of 10(-6) S/cm when temperatures increase to 80 °C. While electrolytes made from multilayer grafted particles show a steep increase in conductivity with temperature with an ionic conductivity increase to 3 × 10(-5) S/cm at 80 °C, with an O/Li ratio of 32. PMID:26284984

  13. Spectroscopic and DFT studies to understand the liquid formation mechanism in the LiTFSI/acetamide complex system.


    Hu, Yongsheng; Wang, Zhaoxiang; Li, Hong; Huang, Xuejie; Chen, Liquan


    It is interesting that although both lithium bis(trifluoromethane sulfone) imide (LiN(SO2CF3)2, LiTFSI) and acetamide (CH3CONH2) are solid, their mixture is a liquid in an appropriate molar ratio range at room temperature. The liquid formation mechanism of the LiTFSI/acetamide complex has been investigated by FT-IR and FT-Raman spectroscopy. The spectroscopic studies show that the Li+ ions coordinate with the C=O group of acetamide whereas the SO2 group in TFSI- anions interacts with the NH2 group of acetamide via hydrogen bonding. These interactions lead to the breakage of the hydrogen bonds between acetamide molecules and to the dissociation of LiTFSI, resulting in the formation of this molten salt. Furthermore, it has been found that moderate interaction between LiX and RCONH2 (R = -NH2, -CH3 and -CF3) is favorable for forming a LiX/RCONH2 molten salt system with low eutectic temperature and high conductivity based on density functional theory (DFT) calculational and experimental comparison for different R groups in RCONH2 and different lithium salts. PMID:15911385

  14. In situ Raman spectroscopy of sulfur speciation in lithium-sulfur batteries.


    Wu, Heng-Liang; Huff, Laura A; Gewirth, Andrew A


    In situ Raman spectroscopy and cyclic voltammetry were used to investigate the mechanism of sulfur reduction in lithium-sulfur battery slurry cathodes with 1 M lithium bis(trifluoromethane sulfonyl)imide (LiTFSI) and tetraethylene glycol dimethyl ether (TEGDME)/1,3-dioxolane (DIOX) (1/1, v/v). Raman spectroscopy shows that long-chain polysulfides (S8(2-)) were formed via S8 ring opening in the first reduction process at ?2.4 V vs Li/Li(+) and short-chain polysulfides such as S4(2-), S4(-), S3(-), and S2O4(2-) were observed with continued discharge at ?2.3 V vs Li/Li(+) in the second reduction process. Elemental sulfur can be reformed in the end of the charge process. Rate constants obtained for the appearance and disappearance polysulfide species shows that short-chain polysulfides are directly formed from S8 decomposition. The rate constants for S8 reappearance and polysulfide disappearance on charge were likewise similar. The formation of polysulfide mixtures at partial discharge was found to be quite stable. The CS2 additive was found to inhibit the sulfur reduction mechanism allowing the formation of long-chain polysulfides during discharge only and stabilizing the S8(2-) product. PMID:25543831

  15. Discovering less toxic ionic liquids by using the Microtox toxicity test.


    Hernndez-Fernndez, F J; Bayo, J; Prez de los Ros, A; Vicente, M A; Bernal, F J; Quesada-Medina, J


    New Microtox toxicity data of 16 ionic liquids of different cationic and anionic composition were determined. The ionic liquids 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate, [BMPyr(+)][TFO(-)], 1-butyl-1-methylpyrrolidinium chloride, [BMPyr(+)][Cl(-)], hydroxypropylmethylimidazolium fluoroacetate, [HOPMIM(+)][FCH2COO(-)], and hydroxypropylmethylimidazolium glycolate [HOPMIM(+)][glycolate(-)] were found to be less toxic than conventional organic solvent such as chloroform or toluene, accoding the Microtox toxicity assays. The toxicity of pyrrolidinium cation was lower than the imidazolium and pyridinium ones. It was found that the inclusion of an hydroxyl group in the alkyl chain length of the cation also reduce the toxicity of the ionic liquid. To sum up, the Microtox toxicity assays can be used as screening tool to easily determined the toxicity of a wide range of ionic liquids and the toxicity data obtained could allow the obtention of structure-toxicity relationships to design less toxic ionic liquids. PMID:25748519

  16. Melting-Point Estimation of Ionic Liquids by a Group Contribution Method

    NASA Astrophysics Data System (ADS)

    Aguirre, Claudia L.; Cisternas, Luis A.; Valderrama, Jos O.


    Based on experimental data collected from the literature, a group contribution method for estimating the melting points of imidazolium-, pyridinium-, pyrrolidinium-, ammonium-, phosphonium-, and piperidinium-based ionic liquids (ILs) with common anions is proposed. The method considers the contributions of ionic groups and methylene groups, as additive parameters, and two nonadditive characteristic geometric parameters of cations such as symmetry and flexibility. A total of 293 data points for 136 ILs were used in this study. The average relative deviation and the average absolute deviation of the proposed model are 7.8% and 22.6 K, respectively. It is concluded that the proposal is useful for the prediction of the melting points for a wide range of ILs.

  17. Physical Properties of Ionic Liquids Consisting of the 1-Butyl-3-Methylimidazolium Cation with Various Anions and the Bis(trifluoromethylsulfonyl)imide Anion with Various Cations

    SciTech Connect

    Jin, Hui; O'Hare, Bernie; Dong, Jing; Arzhantsev, Sergei; Baker, Gary A; Wishart, James F.; Benesi, Alan; Maroncelli, Mark


    Physical properties of 4 room-temperature ionic liquids consisting of the 1-butyl-3-methylimidazolium cation with various perfluorinated anions and the bis(trifluoromethylsulfonyl)imide (Tf2N-) anion with 12 pyrrolidinium-, ammonium-, and hydroxyl-containing cations are reported. Electronic structure methods are used to calculate properties related to the size, shape, and dipole moment of individual ions. Experimental measurements of phase-transition temperatures, densities, refractive indices, surface tensions, solvatochromic polarities based on absorption of Nile Red, 19F chemical shifts of the Tf2N- anion, temperature-dependent viscosities, conductivities, and cation diffusion coefficients are reported. Correlations among the measured quantities as well as the use of surface tension and molar volume for estimating Hildebrand solubility parameters of ionic liquids are also discussed.

  18. Poly(ionic liquid)s as phase splitting promoters in aqueous biphasic systems.


    Joo, Karen G; Tom, Liliana C; Isik, Mehmet; Mecerreyes, David; Marrucho, Isabel M


    Aqueous biphasic systems (ABSs) provide a sustainable and efficient alternative to conventional liquid-liquid extraction techniques with volatile organic solvents, and can be used for the extraction, recovery, and purification of diverse solutes. In this work, and for the first time, ABSs composed of poly(ionic liquid)s (PILs) and inorganic salts were measured at 25 C and atmospheric pressure. New PILs having pyrrolidinium polycations combined with different counter-anions, namely acetate [Ac](-), trifluoroacetate [TFAc](-), hexanoate [Hex](-), adipate [Adi](-), and citrate [Cit](-) were synthesized, by a simple and environmentally-friendly procedure, and characterized. The effect of the PIL features, namely molecular weight and anionic character, and other experimental variables, such as temperature, on the phase splitting ability was researched. The aptitude of the studied ABS to be implemented as separation technologies was also evaluated through the use of a model biomolecule, tryptophan. PMID:26421939

  19. Electrowetting of ionic liquids.


    Millefiorini, Stefano; Tkaczyk, Alan H; Sedev, Rossen; Efthimiadis, Jim; Ralston, John


    We have successfully demonstrated that imidazolium- and pyrrolidinium-based commercial room-temperature ionic liquids can electrowet (with a dc voltage) a smooth fluoropolymer (Teflon AF1600) surface. Qualitatively, the process is analogous to the electrowetting of aqueous electrolyte solutions: the contact angle versus voltage curve has a parabolic shape which saturates at larger voltages (positive or negative). On the other hand we observed several peculiarities: (i) the efficiency is significantly lower (by about an order of magnitude); (ii) the influence of the bulky cation is larger and the importance of the smaller anion is lesser, especially with respect to electrowetting saturation; (iii) there is an asymmetry in the saturation contact angles found for positive and negative voltages. The asymmetry may be correlated with the cation-anion asymmetry of the ionic liquids. The low efficiency may be caused by the presence of water and other impurities in these commercial materials. PMID:16506791

  20. Composite Electrolytes for Lithium Batteries: Ionic Liquids in APTES Crosslinked Polymers

    NASA Technical Reports Server (NTRS)

    Tigelaar, Dean M.; Meador, Mary Ann B.; Bennett, William R.


    Solvent free polymer electrolytes were made consisting of Li(+) and pyrrolidinium salts of trifluoromethanesulfonimide added to a series of hyperbranched poly(ethylene oxide)s (PEO). The polymers were connected by triazine linkages and crosslinked by a sol-gel process to provide mechanical strength. The connecting PEO groups were varied to help understand the effects of polymer structure on electrolyte conductivity in the presence of ionic liquids. Polymers were also made that contain poly(dimethylsiloxane) groups, which provide increased flexibility without interacting with lithium ions. When large amounts of ionic liquid are added, there is little dependence of conductivity on the polymer structure. However, when smaller amounts of ionic liquid are added, the inherent conductivity of the polymer becomes a factor. These electrolytes are more conductive than those made with high molecular weight PEO imbibed with ionic liquids at ambient temperatures, due to the amorphous nature of the polymer.

  1. XPS of guanidinium ionic liquids: a comparison of charge distribution in nitrogenous cations.


    Santos, Ana R; Blundell, Rebecca K; Licence, Peter


    Herein, we investigate the first X-ray photoelectron spectroscopy (XPS) data for a range of functionalised guanidinium based systems that are commonly employed in the dissolution of biomolecules. We define a peak fitting model which allows the direct comparison to more common cation sets including dialkyl-imidazolium, pyrrolidinium, and quaternary ammonium based systems. The measured binding energies (BEs) of the N 1s and C 1s components are presented and notable variations discussed. These data show a large difference between measured binding energies for the Ncation 1s when compared to other families of ionic liquids. These results suggest a weaker anion/cation interaction thus the anion is more able to interact with a solid matrix, i.e. keratin, silk, chitin, collagen, cellulose, and become more active in dissolution. PMID:25868478

  2. Synthesis and characterization of 5-cyanotetrazolide-based ionic liquids.


    Bergholz, Timm; Oelkers, Benjamin; Huber, Benedikt; Roling, Bernhard; Sundermeyer, Jrg


    New salts based on imidazolium, pyrrolidinium, phosphonium, guanidinium, and ammonium cations together with the 5-cyanotetrazolide anion [C2 N5 ](-) are reported. Depending on the nature of cation-anion interactions, characterized by XRD, the ionic liquids (ILs) have a low viscosity and are liquid at room temperature or have higher melting temperatures. Thermogravimetric analysis, cyclic voltammetry, viscosimetry, and impedance spectroscopy display a thermal stability up to 230?C, an electrochemical window of 4.5?V, a viscosity of 25?mPa?s at 20?C, and an ionic conductivity of 5.4 mS cm(-1) at 20?C for the IL 1-butyl-1-methylpyrrolidinium 5-cyanotetrazolide [BMPyr][C2 N5 ]. On the basis of these results, the synthesized compounds are promising electrolytes for lithium-ion batteries. PMID:25504790

  3. Benzene solubility in ionic liquids: working toward an understanding of liquid clathrate formation.


    Pereira, Jorge F B; Flores, Luis A; Wang, Hui; Rogers, Robin D


    The solubility of benzene in 15 imidazolium, pyrrolidinium, pyridinium, and piperidinium ionic liquids has been determined; the resulting, benzene-saturated ionic liquid solutions, also known as liquid clathrates, were examined with (1) H and (19) F nuclear magnetic resonance spectroscopy to try and understand the molecular interactions that control liquid clathrate formation. The results suggest that benzene interacts primarily with the cation of the ionic liquid, and that liquid clathrate formation (and benzene solubility) is controlled by the strength of the cation-anion interactions, that is, the stronger the cation-anion interaction, the lower the benzene solubility. Other factors that were determined to be important in the final amount of benzene in any given liquid clathrate phase included attractive interactions between the anion and benzene (when significant), and larger steric or free volume demands of the ions, both of which lead to greater benzene solubility. PMID:25297708

  4. Metsulfuron-methyl-based herbicidal ionic liquids.


    Pernak, Juliusz; Niemczak, Micha?; Shamshina, Julia L; Gurau, Gabriela; G?owacki, Grzegorz; Praczyk, Tadeusz; Marcinkowska, Katarzyna; Rogers, Robin D


    Ten sulfonylurea-based herbicidal ionic liquids (HILs) were prepared by combining the metsulfuron-methyl anion with various cation types including quaternary ammonium ([bis(2-hydroxyethyl)methyloleylammonium](+), [2-hydroxyethyltrimethylammonium](+)), pyridinium ([1-dodecylpyridinium](+)), piperidinium ([1-methyl-1-propylpiperidinium](+)), imidazolium ([1-allyl-3-methylimidazolium](+), [1-butyl-3-methylimidazolium](+)), pyrrolidinium ([1-butyl-1-methylpyrrolidinium](+)), morpholinium ([4-decyl-4-methylmorpholinium](+)), and phosphonium ([trihexyltetradecylphosphonium](+) and [tetrabutylphosphonium](+)). Their herbicidal efficacy was studied in both greenhouse tests and field trials. Preliminary results for the greenhouse tests showed at least twice the activity for all HILs when compared to the activity of commercial Galmet 20 SG, with HILs with phosphonium cations being the most effective. The results of two-year field studies showed significantly less enhancement of activity than observed in the greenhouse; nonetheless, it was found that the herbicidal efficacy was higher than that of the commercial analog, and efficacy varied depending on the plant species. PMID:25734891

  5. Spectroscopic and computational analysis of the molecular interactions in the ionic liquid ion pair [BMP]{sup +}[TFSI]{sup -}

    SciTech Connect

    Mao, James X.; Nulwala, Hunaid B.; Luebke, David R.; Damodaran, Krishnan


    1-Butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([BMP]{sup +}[TFSI]{sup ?}) ion pairs were studied using DFT at the B3LYP/6-31 + G(d) level. Nine locally stable conformations of the ion pair were located. In the most stable conformation, [TFSI]{sup ?} takes a cis conformation and lies below the pyrrolidinium ring. Atoms-in-molecules (AIM) and electron density analysis indicated the existence of nine hydrogen bonds. Interaction energies were recalculated at the Second-order MllerPlesset (MP2) level to show the importance of dispersion interaction. Further investigation through natural bond orbital (NBO) analysis provided insight into the importance of charge transfer interactions in the ion pair. Harmonic vibrations of the ion pair were calculated and compared with vibrations of the free ions as well as the experimental infrared spectrum. Assignments and frequency shifts are discussed in light of the inter-ionic interactions.

  6. Mixtures of protic ionic liquids and propylene carbonate as advanced electrolytes for lithium-ion batteries.


    Vogl, T; Menne, S; Balducci, A


    In this study we investigated the chemical-physical properties of mixtures containing the protic ionic liquid (PIL) N-butyl-pyrrolidinium bis(trifluoromethanesulfonyl)imide (PYRH4TFSI), propylene carbonate (PC) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) in view of their use as electrolytes for lithium-ion batteries (LIBs). We showed that these electrolytic solutions might display conductivity and viscosity comparable to those of conventional electrolytes. Depending on the amount of PIL present inside the mixtures, such mixtures might also display the ability to suppress the anodic dissolution of Al. Furthermore, we showed that the coordination of lithium ions by TFSI in PIL-PC mixtures appears to be different than the one observed for mixtures of PC and aprotic ionic liquids (AILs). When used in combination with a battery electrode, e.g. lithium iron phosphate (LFP), these mixtures allow the achievement of high performance also at a very high C-rate. PMID:25328075

  7. 3-Methylpiperidinium ionic liquids.


    Belhocine, Tayeb; Forsyth, Stewart A; Gunaratne, H Q Nimal; Nieuwenhuyzen, Mark; Nockemann, Peter; Puga, Alberto V; Seddon, Kenneth R; Srinivasan, Geetha; Whiston, Keith


    A wide range of room temperature ionic liquids based on the 3-methylpiperdinium cation core were produced from 3-methylpiperidine, which is a derivative of DYTEK A amine. First, reaction with 1-bromoalkanes or 1-bromoalkoxyalkanes generated the corresponding tertiary amines (Rm?pip, R = alkyl or alkoxyalkyl); further quaternisation reactions with the appropriate methylating agents yielded the quaternary [Rmm?pip]X salts (X(-) = I(-), [CF3CO2](-) or [OTf](-); Tf = -SO2CF3), and [Rmm?pip][NTf2] were prepared by anion metathesis from the corresponding iodides. All [NTf2](-) salts are liquids at room temperature. [Rmm?pip]X (X(-) = I(-), [CF3CO2](-) or [OTf](-)) are low-melting solids when R = alkyl, but room temperature liquids upon introduction of ether functionalities on R. Neither of the 3-methylpiperdinium ionic liquids showed any signs of crystallisation, even well below 0 C. Some related non-C-substituted piperidinium and pyrrolidinium analogues were prepared and studied for comparison. Crystal structures of 1-hexyl-1,3-dimethylpiperidinium tetraphenylborate, 1-butyl-3-methylpiperidinium bromide, 1-(2-methoxyethyl)-1-methylpiperidinium chloride and 1-(2-methoxyethyl)-1-methylpyrrolidinium bromide are reported. Extensive structural and physical data are collected and compared to literature data, with special emphasis on the systematic study of the cation ring size and/or asymmetry effects on density, viscosity and ionic conductivity, allowing general trends to be outlined. Cyclic voltammetry shows that 3-methylpiperidinium ionic liquids, similarly to azepanium, piperidinium or pyrrolidinium counterparts, are extremely electrochemically stable; the portfolio of useful alternatives for safe and high-performing electrolytes is thus greatly extended. PMID:25669485

  8. Soft glassy colloidal arrays in an ionic liquid: colloidal glass transition, ionic transport, and structural color in relation to microstructure.


    Ueno, Kazuhide; Sano, Yuta; Inaba, Aya; Kondoh, Masashi; Watanabe, Masayoshi


    The colloidal glass transition, ionic transport, and optical properties of soft glassy colloidal arrays (SGCAs) that consist of poly(methyl methacrylate) (PMMA)-grafted silica nanoparticles (PMMA-g-NPs) and a room-temperature ionic liquid, 1-ethyl-3-methylimidazolium bis(trifluoromethane sulfonyl)amide ([C(2)mim][NTf(2)]), were investigated. At lower particle concentrations, PMMA-g-NPs were well-suspended in the IL without any aggregation or sedimentation, and the dilute suspensions showed liquid-like behavior. However, above a certain particle concentration, the suspensions became solidified and exhibited different structural colors depending on the particle concentrations. The liquid-solid transition of the SGCAs was essentially caused by colloidal glass transition. Due to the soft repulsive interaction between the particles, the effective volume fraction of the particle (?(eff)) required for colloidal glass transition was higher than that of the hard sphere system and found to be approximately 0.70-0.74. The SGCA had sufficient ionic conductivity, which was greater than 10(-3) S cm(-1) at room temperature, even in the highly concentrated region. For ionic transport of the cation and the anion in the SGCAs, the decrease in diffusivity observed with the addition of the particles (D(g)/D(0)) was slightly greater for the [NTf(2)] anion than that of the [C(2)mim] cation, suggesting that the [NTf(2)] anion preferentially interacts with the PMMA chains. The SGCAs showed homogeneous, nonbrilliant, and angle-independent structural colors above the glass transition volume fraction. In addition, the color of the SGCAs changed from red to green to blue as the particle concentration increased. A linear relationship was found between the maximum wavelength of the reflection spectra and the center-to-center distance in the SGCAs. PMID:20879726

  9. Control of the recombination rate by changing the polarity of the electrolyte in dye-sensitized solar cells.


    Idigoras, Jess; Tena-Zaera, Ramn; Anta, Juan A


    Recombination in Dye-sensitized Solar Cells (DSCs) is an electron transfer process critical for high efficiency. The chemical nature of the electron acceptor is known to have an important impact on recombination and, hence, limits the choice of hole conductors in DSCs and related solar cells. In this respect, Room Temperature Ionic liquids (RTILs) have been recognized as an alternative to volatile organic solvents due to their negligible vapor pressure, which offers the chance for long-term stability. However, RTIL-based electrolytes lead to lower performance, a feature that has been attributed to the high viscosity of ionic liquids and the mass-transport limitation associated with it. In this work we show that the origin of the lower performance is also related to an increase in the recombination loss due to the polar nature of the RTIL and the influence of the reorganization energy of the electron acceptor in a polar environment. To investigate this chemical effect, different mixing ratios of RTILs and an organic solvent (acetonitrile) have been considered. The fabricated devices have been characterized by small-perturbation techniques (Impedance Electrochemical Spectroscopy and Intensity-Modulated Photovoltage and Photocurrent Spectroscopies) and Open-Circuit Voltage Decay measurements, which have been used to extract electron lifetimes at different applied voltages. Two different ruthenium dyes (hydrophilic N719 and hydrophobic Z907) and two different cations in the RTIL (imidazolium- and pyrrolidinium-based) have been considered. The results obtained show that for pure ionic liquids the lifetime-voltage curve is exponential, which is a signature of large reorganization energies for electron transfer. In contrast, pure acetonitrile exhibits a non-exponential behavior, which is consistent with relatively low reorganization energy. Interestingly, and as a general rule, we find that recombination is faster in systems with higher reorganization energies. This is interpreted as a consequence of the availability of more acceptor states for electron transfer. In addition, it is found that mixing RTILs and acetonitrile is an interesting strategy to increase the stability of DSCs without significant recombination losses, provided that the right dye and RTIL, in particular, a pyrrolidinium component, are used. PMID:25184736

  10. Structural and electrochemical properties of succinonitrile-based gel polymer electrolytes: role of ionic liquid addition.


    Suleman, Mohd; Kumar, Yogesh; Hashmi, S A


    Experimental studies on the novel compositions of gel polymer electrolytes, comprised of plastic crystal succinonitrile (SN) dispersed with pyrrolidinium and imidazolium-based ionic liquids (ILs) entrapped in a host polymer poly(vinylidine fluoride-co-hexafluoropropylene) (PVdF-HFP), are reported. The gel electrolytes are in the form of free-standing films with excellent mechanical, thermal, and electrochemical stability. The introduction of even a small content (~1 wt %) of ionic liquid (1-butyl-1-methylpyrrolidinium bis(trifluoromethyl-sulfonyl)imide (BMPTFSI) or 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMITf) in the PVdF-HFP/SN system (1:4 w/w) enhances the electrical conductivity by 4 orders of magnitude, that is, from ~10(-7) to ~10(-3) S cm(-1) at room temperature. The structural changes due to the entrapment of SN or SN/ILs mixtures and ion-SN-polymer interactions are examined by Fourier transform infrared (FTIR)/Raman spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), and differential scanning calorimmetry (DSC). Various physicochemical properties and fast ion conduction in the gel polymer membranes show their promising characteristics as electrolytes in different ionic devices including supercapacitors. PMID:23758408

  11. Kinetics and mass spectrometric measurements of myoglobin unfolding in aqueous ionic liquid solutions.


    Miller, Miranda C; Hanna, Sylvia L; DeFrates, Kelsey G; Fiebig, Olivia C; Vaden, Timothy D


    Recent studies have characterized the effects of aqueous ionic liquids on myoglobin unfolding for the broader purposes of understanding their effects on protein structures, stabilities, and ultimately biocompatibilities for future applications. Here, we investigated the effects of four different ionic liquids (ILs) on the thermal stability, unfolding kinetics, and tertiary shape of myoglobin. We compared results for four different ILs: 1-butyl-3-methyl imidazolium tetrafluoroborate (BMIBF4); 1-butyl-3-methyl pyrrolidinium tetrafluoroborate (PyrrBF4); 1-ethyl-3-methyl imidazolium acetate (EMIAc); and tetramethylguanidinium acetate (TMGAc). Results showed that ILs accelerate myoglobin unfolding kinetics both through aqueous solution ionic strength effects and ionic liquid-specific effects. Arrhenius plots of observed rate constants reveal that some ILs lower the energy barrier to unfolding, possibly by destabilizing the native protein state. The magnitude of these ionic liquid effects correlates with their effects on protein thermodynamic stabilities. Hydrogen-deuterium exchange (HDX) experiments using ESI-MS showed that myoglobin exhibits a more open, and presumably less stable, tertiary shape in aqueous IL solutions. Overall, BMIBF4 and TMGAc exhibit the strongest effect on the myoglobin stability, unfolding rate, and tertiary structure while PyrrBF4 and EMIAc have weaker effects under our experimental conditions. PMID:26751398

  12. Thallium Transfer from Hydrochloric Acid Media into Pure Ionic Liquids.


    Tereshatov, Evgeny E; Boltoeva, Maria Yu; Mazan, Valerie; Volia, Merinda F; Folden, Charles M


    Pure hydrophobic ionic liquids are known to extract metallic species from aqueous solutions. In this work we have systematically investigated thallium (Tl) extraction from aqueous hydrochloric acid (HCl) solutions into six pure fluorinated ionic liquids, namely imidazolium- and pyrrolidinium-based ionic liquids with bis(trifluoromethanesulfonyl)imide and bis(fluorosulfonyl)-imide anions. The dependence of the Tl extraction efficiency on the structure and composition of the ionic liquid ions, metal oxidation state, and initial metal and aqueous acid concentrations have been studied. Tl concentrations were on the order of picomolar (analyzed using radioactive tracers) and millimolar (analyzed using inductively coupled plasma mass spectrometry). The extraction of the cationic thallium species Tl(+) is higher for ionic liquids with more hydrophilic cations, while for the TlXz(3-z) anionic species (where X = Cl(-) and/or Br(-)), the extraction efficiency is greater for ionic liquids with more hydrophobic cations. The highest distribution value of Tl(III) was approximately 2000. An improved mathematical model based on ion exchange and ion pair formation mechanisms has been developed to describe the coextraction of two different anionic species, and the relative contributions of each mechanism have been determined. PMID:26769597

  13. Evidence for laser-induced formation of solvated electrons in room temperature ionic liquids.


    Chandrasekhar, N; Endres, F; Unterreiner, A-N


    The photolytic generation of solvated electrons was observed for the first time in two room temperature ionic liquids (RTILs), trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl)imide (IL) and 1-butyl-1-methyl-pyrrolidinium bis(trifluoromethylsulfonyl)imide (IL). A 70 fs UV-pulse was used to excite the RTILs, while the transient response was monitored in the visible and near-infrared spectral regions. Immediately after excitation, a pulse duration limited rise of the induced absorption indicated the formation of solvated electrons suggesting the existence of pre-formed traps in RTILs. A broad transient absorption spectrum with a full width at half maximum of about 0.9 eV, typical for solvated electrons, was reconstructed from the transient profiles. Wavelength-independent relaxation dynamics at longer delay times suggest a lifetime of solvated electrons in the ns regime in agreement with results from pulse radiolysis studies. Adding 1,1-dimethylpyrrolidinium iodide to IL led to an increase of the UV absorbance and consequently, to an increase of the yield of solvated electrons. Furthermore, this solute is an efficient electron scavenger causing the transients to decay within about 40 ps. PMID:16902711

  14. Ionic liquids effects on the permeability of photosynthetic membranes probed by the electrochromic shift of endogenous carotenoids.


    Malferrari, Marco; Malferrari, Danilo; Francia, Francesco; Galletti, Paola; Tagliavini, Emilio; Venturoli, Giovanni


    Ionic liquids (ILs) are promising materials exploited as solvents and media in many innovative applications, some already used at the industrial scale. The chemical structure and physicochemical properties of ILs can differ significantly according to the specific applications for which they have been synthesized. As a consequence, their interaction with biological entities and toxicity can vary substantially. To select highly effective and minimally harmful ILs, these properties need to be investigated. Here we use the so called chromatophores - protein-phospholipid membrane vesicles obtained from the photosynthetic bacterium Rhodobacter sphaeroides- to assess the effects of imidazolinium and pyrrolidinium ILs, with chloride or dicyanamide as counter anions, on the ionic permeability of a native biological membrane. The extent and modalities by which these ILs affect the ionic conductivity can be studied in chromatophores by analyzing the electrochromic response of endogenous carotenoids, acting as an intramembrane voltmeter at the molecular level. We show that chromatophores represent an in vitro experimental model suitable to probe permeability changes induced in cell membranes by ILs differing in chemical nature, degree of oxygenation of the cationic moiety and counter anion. PMID:26343161

  15. Effect of cation type, alkyl chain length, adsorbate size on adsorption kinetics and isotherms of bromide ionic liquids from aqueous solutions onto microporous fabric and granulated activated carbons.


    Hassan, Safia; Duclaux, Laurent; Lvque, Jean-Marc; Reinert, Laurence; Farooq, Amjad; Yasin, Tariq


    The adsorption from aqueous solution of imidazolium, pyrrolidinium and pyridinium based bromide ionic liquids (ILs) having different alkyl chain lengths was investigated on two types of microporous activated carbons: a fabric and a granulated one, well characterized in terms of surface chemistry by "Boehm" titrations and pH of point of zero charge measurements and of porosity by N2 adsorption at 77K and CO2 adsorption at 273K. The influence of cation type, alkyl chain length and adsorbate size on the adsorption properties was analyzed by studying kinetics and isotherms of eight different ILs using conductivity measurements. Equilibrium studies were carried out at different temperatures in the range [25-55C]. The incorporation of ILs on the AC porosity was studied by N2 adsorption-desorption measurements at 77K. The experimental adsorption isotherms data showed a good correlation with the Langmuir model. Thermodynamic studies indicated that the adsorption of ILs onto activated carbons was an exothermic process, and that the removal efficiency increased with increase in alkyl chain length, due to the increase in hydrophobicity of long chain ILs cations determined with the evolution of the calculated octanol-water constant (Kow). The negative values of free energies indicated that adsorption of ILs with long chain lengths having hydrophobic cations was more spontaneous at the investigated temperatures. PMID:24929502

  16. Electrochemical reduction of O2 in 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide ionic liquid containing Zn2+ cations: deposition of non-polar oriented ZnO nanocrystalline films.


    Azaceta, Eneko; Marcilla, Rebeca; Mecerreyes, David; Ungureanu, Mariana; Dev, Apurba; Voss, Tobias; Fantini, Sebastian; Grande, Hans-Jurgen; Cabaero, German; Tena-Zaera, Ramon


    The influence of the Zn(2+) concentration and temperature on the electrochemical reduction of O(2) in a solution of zinc bis(trifluoromethanesulfonyl)imide (Zn(TFSI)(2)) salt in 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PYR(14)TFSI) ionic liquid is presented. ZnO nanocrystalline films were then electrodeposited, under enhanced O(2) reduction, at temperatures in the 75-150 C range. Their morphology, chemical composition, structural and optical properties were analyzed. In contrast to the polar-oriented ZnO usually obtained from aqueous and conventional solvent based electrolytes, nanocrystalline films oriented along non-polar directions, (11 ?10) and (11 ?20), were obtained from this ionic liquid electrolyte. A significant content of carbon was detected in the films, pointing to the active participation and crucial effect of pyrrolidinium cation (and/or byproducts) during the electrodeposition. The films showed semiconducting behavior with an optical gap between 3.43 and 3.53 eV as measured by optical transmittance. Their room temperature photoluminescence spectra exhibited two different bands centered at ?3.4 and ?2.2 eV. The intensity ratio between both bands was found to depend on the deposition temperature. This work demonstrates the great potential of ionic liquids based electrolytes for the electrodeposition of ZnO nanocrystalline thin films with innovative microstructural and optoelectronic properties. PMID:21709895

  17. Ionic liquids as novel solvents for ionic polymer transducers

    NASA Astrophysics Data System (ADS)

    Bennett, Matthew D.; Leo, Donald J.


    The use of ionic liquids as solvents for ionic polymer (specifically, Nafion) transducers is demonstrated. Ionic liquids are attractive for this application because of their high inherent stability. Ionic liquids are salts that exist as liquids at room temperature and have no measureable vapor pressure. Therefore, the use of ionic liquids as solvents for ionic polymer transducers can eliminate the traditional problem of water evaporation in these devices. Another benefit of the use of ionic liquids in this way is the reduction or elimination of the characteristic back-relaxation common in water-solvated ionic polymer actuators. The results demonstrate that the viscosity of the ionic liquid and the degree to which the ionic liquid swells the membrane are the important physical parameters to consider. Five ionic liquids were studied, based on substituted pyrrolidinium, phosphonium, or imidazolium cations and fluoroanions. Of these five ionic liquids, transduction is demonstrated in three of them and the best results are obtained with 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ionic liquid. This substance has an electrochemical stability window of 4.1 V, a melting point of -10 C, and a viscosity of 35-45 cP [19]. Results demonstrate that platinum-plated Nafion transducers solvated with this ionic liquid exhibit sensing and actuation responses and that these transducers are stable in air. Endurance testing of this sample reveals a decrease in the free strain of only 25 % after 250,000 actuation cycles in air.

  18. Exploring electrochemical windows of room-temperature ionic liquids: a computational study.


    Tian, Yong-Hui; Goff, George S; Runde, Wolfgang H; Batista, Enrique R


    Room-temperature ionic liquids (RTILs) are regarded as green solvents due to their low volatility, low flammability, and thermal stability. RTILs exhibit wide electrochemical windows, making them prime candidates as media for electrochemically driven reactions such as electro-catalysis and electro-plating for separations applications. Therefore, understanding the factors determining edges of the electrochemical window, the electrochemical stability of the RTILs, and the degradation products is crucial to improve the efficiency and applicability of these systems. We present here computational investigations of the electrochemical properties of a variety of RTILs covering a wide range of electrochemical windows. We proposed four different approaches with different degrees of approximation and computational cost from gas-phase calculations to full explicit solvation models. It was found that, whereas the simplest model has significant flaws in accuracy, implicit and explicit solvent models can be used to reliably predict experimental data. The general trend of electrochemical windows of the RTILs studied is well reproduced, showing that it increases in the order of imidazolium < ammonium < pyrrolidinium < phosphonium giving confidence to the methodology presented to use it in screening studies of ionic liquids. PMID:22946441

  19. Probing HSA-ionic liquid interactions by spectroscopic and molecular docking methods.


    Kumari, Meena; Maurya, Jitendra Kumar; Tasleem, Munazzah; Singh, Prashant; Patel, Rajan


    Herein, we report the interaction of synthesized pyrrolidinium based ionic liquid, N-butyl-N-methyl-2-oxopyrrolidinium bromide (BMOP) with human serum albumin (HSA). The BMOP was characterized by using (1)H NMR, (13)C NMR and FT-IR techniques. The critical micelle concentration (cmc) of BMOP was confirmed by surface tension, conductivity and contact angle measurements. The interactions between HSA and BMOP were studied by steady-state and time-resolved fluorescence, UV-visible, FT-IR spectroscopic and molecular docking methods. The steady-state fluorescence spectra showed that BMOP quenched the fluorescence of HSA through combined quenching mechanism. Corresponding thermodynamic parameters viz. Gibbs free energy change (?G), entropy change (?S) and enthalpy change (?H) illustrated that the binding process was spontaneous and entropy driven. It is also suggested that hydrophobic forces play a key role in the binding of BMOP to HSA. In addition, the pyrene probe analysis again suggests the involvement of hydrophobic interaction in HSA-BMOP complex formation. Surface tension profile showed that the cmc value of BMOP in the presence of HSA is higher than the cmc value of pure BMOP. The FT-IR results show a conformational change in the secondary structure of HSA upon the addition of BMOP. The molecular docking result indicated that BMOP binds with HSA at hydrophobic pocket domain IIA with hydrophobic and hydrogen bond interactions in which hydrophobic interactions are dominating. PMID:24911269

  20. Characterization of phosphonium ionic liquids through a linear solvation energy relationship and their use as GLC stationary phases.


    Breitbach, Zachary S; Armstrong, Daniel W


    In recent years, room temperature ionic liquids (RTILs) have proven to be of great interest to analytical chemists. One important development is the use of RTILs as highly thermally stable GLC stationary phases. To date, nearly all of the RTIL stationary phases have been nitrogen-based (ammonium, pyrrolidinium, imidazolium, etc.). In this work, eight new monocationic and three new dicationic phosphonium-based RTILs are used as gas-liquid chromatography (GLC) stationary phases. Inverse gas chromatography (GC) analyses are used to study the solvation properties of the phosphonium RTILs through a linear solvation energy model. This model describes the multiple solvation interactions that the phosphonium RTILs can undergo and is useful in understanding their properties. In addition, the phosphonium-based stationary phases are used to separate complex analyte mixtures by GLC. Results show that the small differences in the solvent properties of the phosphonium ILs compared with ammonium-based ILs will allow for different and unique separation selectivities. Also, the phosphonium-based stationary phases tend to be more thermally stable than nitrogen-based ILs, which is an advantage in many GC applications. PMID:18274737

  1. Extraction separation of rare-earth ions via competitive ligand complexations between aqueous and ionic-liquid phases.


    Sun, Xiaoqi; Bell, Jason R; Luo, Huimin; Dai, Sheng


    The extraction separation of rare earth elements is one of the most challenging separation processes in hydrometallurgy and advanced nuclear fuel cycles. The TALSPEAK process (trivalent actinide lanthanide separations by phosphorus-reagent extraction from aqueous komplexes) is a prime example of these separation processes. The objective of this paper is to explore the use of ionic liquids (ILs) for the TALSPEAK-like process, to further enhance its extraction efficiencies for lanthanides, and to investigate the potential of using this modified TALSPEAK process for separation of lanthanides among themselves. Eight imidazolium ILs ([C(n)mim][NTf(2)] and [C(n)mim][BETI], n = 4,6,8,10) and one pyrrolidinium IL ([C(4)mPy][NTf(2)]) were investigated as diluents using di(2-ethylhexyl)phosphoric acid (HDEHP) as an extractant for the separation of lanthanide ions from aqueous solutions of 50 mM glycolic acid or citric acid and 5 mM diethylenetriamine pentaacetic acid (DTPA). The extraction efficiencies were studied in comparison with diisopropylbenzene (DIPB), an organic solvent used as a diluent for the conventional TALSPEAK extraction system. Excellent extraction efficiencies and selectivities were found for a number of lanthanide ions using HDEHP as an extractant in these ILs. The effects of different alkyl chain lengths in the cations of ILs and of different anions on extraction efficiencies and selectivities of lanthanide ions are also presented in this paper. PMID:21735029

  2. Ionic liquid-assisted sonochemical preparation of CeO2 nanoparticles for CO oxidation


    Alammar, Tarek; Noei, Heshmat; Wang, Yuemin; Grünert, Wolfgang; Mudring, Anja -Verena


    CeO2 nanoparticles were synthesized via a one-step ultrasound synthesis in different kinds of ionic liquids based on bis(trifluoromethanesulfonylamide, [Tf2N]–, in combination with various cations including 1-butyl-3-methylimidazolium ([C4mim]+), 1-ethyl-2,3-dimethylimidazolium ([Edimim]+), butyl-pyridinium([Py4]+), 1-butyl-1-methyl-pyrrolidinium ([Pyrr14]+), and 2-hydroxyethyl-trimethylammonium ([N1112OH]+). Depending on synthetic parameters, such as ionic liquid, Ce(IV) precursor, heating method, and precipitator, formed ceria exhibits different morphologies, varying from nanospheres, nanorods, nanoribbons, and nanoflowers. The morphology, crystallinity, and chemical composition of the obtained materials were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDX), Raman spectroscopy, and N2 adsorption. The structural and electronic propertiesmore » of the as-prepared CeO2 samples were probed by CO adsorption using IR spectroscopy under ultrahigh vacuum conditions. The catalytic activities of CeO2 nanoparticles were investigated in the oxidation of CO. CeO2 nanospheres obtained sonochemically in [C4mim][Tf2N] exhibit the best performance for low-temperature CO oxidation. As a result, the superior catalytic performance of this material can be related to its mesoporous structure, small particle size, large surface area, and high number of surface oxygen vacancy sites.« less

  3. Photodetachment, electron cooling, and recombination, in a series of neat aliphatic room temperature ionic liquids

    NASA Astrophysics Data System (ADS)

    Molins i Domenech, Francesc; Healy, Andrew T.; Blank, David A.


    Transient absorption following photodetachment of a series of neat methyl-alkyl-pyrrolidinium bis(trifluoromethylsulfonyl)amides at 6.20 eV was measured with sub-picosecond time resolution in the visible and near-IR portions of the spectrum. This series spans the onset of structuring in the liquids in the form of polarity alternation. Excitation promotes the electron into a delocalized state with a very large reactive radius. Strong transient absorption is observed in the visible spectrum with a 700 fs lifetime, and much weaker, long-lived absorption is observed in the near-IR spectrum. Absorption in the visible is shown to be consistent with the hole, and absorption in the near-IR is assigned to the free solvated electron. Yield of free electrons is estimated at 4%, is insensitive to the size of the cation, and is determined in less than 1 ps. Solvation of free electrons depends strongly on the size of the cation and correlates well with the viscosity of the liquid. In addition to radiolytic stability of the aliphatic cations, ultrafast, efficient recombination of separated charge in NTf2 - based ionic liquids following photo-excitation near the band-gap may prevent subsequent reactive damage associated with anions.

  4. Effect of Monomer Structure on Curing Behavior, CO2 Solubility, and Gas Permeability of Ionic Liquid-Based Epoxy-Amine Resins and Ion-Gels

    SciTech Connect

    McDanel, WM; Cowan, MG; Barton, JA; Gin, DL; Noble, RD


    New imidazolium- and pyrrolidinium-based bis(epoxide)-functionalized ionic liquid (IL) monorners were synthesized: and reacted with multifunctional amine monomers to produce cross-linked, epoxy-amine poly(ionic liquid) (PIL) resins and PIL/IL ion-gel membranes. The length and chemical nature (i.e., alkyl versus ether) between the irrildazolium group and epokitie groups were studied to determine their effects on CO2 affinity. The CO2 uptake (millimoles per gram) of the epoxy amine resins (between 0.1 and 1 mmol/g) was found to depend predominately on the epoxide-to-amine ratio and the bis(epoxide) IL molecular weight. The effect of using a primary versus a secondary amine-containing multifunctional monoiner was also assessed for the resin-synthesis. Secondary amines can increase CO2 permeability but also increase the iime required for biS(epoxide) coriversion. When either the epoxide or athine monomer structure is changed, the CO2 solubility and permeability of the resulting PIL resins and ion-sel membranes can be tuned.

  5. Nonaborane and decaborane cluster anions can enhance the ignition delay in hypergolic ionic liquids and induce hypergolicity in molecular solvents.


    McCrary, Parker D; Barber, Patrick S; Kelley, Steven P; Rogers, Robin D


    The dissolution of nido-decaborane, B10H14, in ionic liquids that are hypergolic (fuels that spontaneously ignite upon contact with an appropriate oxidizer), 1-butyl-3-methylimidazolium dicyanamide, 1-methyl-4-amino-1,2,4-triazolium dicyanamide, and 1-allyl-3-methylimidazolium dicyanamide, led to the in situ generation of a nonaborane cluster anion, [B9H14](-), and reductions in ignition delays for the ionic liquids suggesting salts of borane anions could enhance hypergolic properties of ionic liquids. To explore these results, four salts based on [B10H13](-) and [B9H14](-), triethylammonium nido-decaborane, tetraethylammonium nido-decaborane, 1-ethyl-3-methylimidazolium arachno-nonaborane, and N-butyl-N-methyl-pyrrolidinium arachano-nonaborane were synthesized from nido-decaborane by reaction of triethylamine or tetraethylammonium hydroxide with nido-decaborane in the case of salts containing the decaborane anion or via metathesis reactions between sodium nonaborane (Na[B9H14]) and the corresponding organic chloride in the case of the salts containing the nonaborane anion. These borane cluster anion salts form stable solutions in some combustible polar aprotic solvents such as tetrahydrofuran and ethyl acetate and trigger hypergolic reactivity of these solutions. Solutions of these salts in polar protic solvents are not hypergolic. PMID:24716643

  6. Automated cytochrome c oxidase bioassay developed for ionic liquids' toxicity assessment.


    Costa, Susana P F; Martins, Bárbara S F; Pinto, Paula C A G; Saraiva, M Lúcia M F S


    A fully automated cytochrome c oxidase assay resorting to sequential injection analysis (SIA) was developed for the first time and implemented to evaluate potential toxic compounds. The bioassay was validated by evaluation of 15 ionic liquids (ILs) with distinct cationic head groups, alkyl side chains and anions. The assay was based on cytochrome c oxidase activity reduction in presence of tested compounds and quantification of inhibitor concentration required to cause 50% of enzyme activity inhibition (EC50). The obtained results demonstrated that enzyme activity was considerably inhibited by BF4 anion and ILs incorporating non-aromatic pyrrolidinium and tetrabutylphosphonium cation cores. Emim [Ac] and chol [Ac], on contrary, presented the higher EC50 values among the ILs tested. The developed automated SIA methodology is a simple and robust high-throughput screening bioassay and exhibited good repeatability in all the tested conditions (rsd<3.7%, n=10). Therefore, it is expected that due to its simplicity and low cost, the developed approach can be used as alternative to traditional screening assays for evaluation of ILs toxicity and identification of possible toxicophore structures. Additionally, the results presented in this study provide further information about ILs toxicity. PMID:26894289

  7. Polymeric ionic liquid-plastic crystal composite electrolytes for lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Li, Xiaowei; Zhang, Zhengxi; Li, Sijian; Yang, Li; Hirano, Shin-ichi


    In this work, composite polymer electrolytes (CPEs), that is, 80%[(1-x)PIL-(x)SN]-20%LiTFSI, are successfully prepared by using a pyrrolidinium-based polymeric ionic liquid (P(DADMA)TFSI) as a polymer host, succinonitrile (SN) as a plastic crystal, and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) as a lithium salt. XRD and DSC measurements confirm that the as-obtained CPEs have amorphous structures. The 80%[50%PIL-50%SN]-20%LiTFSI (50% SN) electrolyte reveals a high room temperature ionic conductivity of 5.74 × 10-4 S cm-1, a wide electrochemical window of 5.5 V, as well as good mechanical strength with a Young's modulus of 4.9 MPa. Li/LiFePO4 cells assembled with the 50% SN electrolyte at 0.1C rate can deliver a discharge capacity of about 150 mAh g-1 at 25 °C, with excellent capacity retention. Furthermore, such cells are able to achieve stable discharge capacities of 131.8 and 121.2 mAh g-1 at 0.5C and 1.0C rate, respectively. The impressive findings demonstrate that the electrolyte system prepared in this work has great potential for application in lithium ion batteries.

  8. Measurements of the complete solvation response in ionic liquids.


    Arzhantsev, Sergei; Jin, Hui; Baker, Gary A; Maroncelli, Mark


    Dynamic Stokes shift measurements of the solvatochromic probe trans-4-dimethylamino-4'-cyanostilbene were used to measure the solvation response of five imidazolium and one pyrrolidinium ionic liquid at 25 degrees C. The Kerr-gated emission and time-correlated single-photon-counting techniques were used to measure spectral dynamics occurring over the time ranges of 100 fs-200 ps and 50 ps-5 ns, respectively, and a combination of data sets from these two techniques enabled observation of the complete solvation response. Observed response functions were found to be biphasic, consisting of a sub-picosecond component of modest (10-20%) amplitude and a dominant slower component relaxing over times of a few picoseconds to several nanoseconds. The faster component could be correlated to inertial characteristics of the constituent ions, and the slower component to solvent viscosity. Dielectric continuum calculations of the sort previously used to predict solvation dynamics in dipolar liquids were shown to work poorly for predicting the response in these ionic liquids. PMID:17319715

  9. Ionic liquids for rechargeable lithium batteries

    SciTech Connect

    Salminen, Justin; Papaiconomou, Nicolas; Kerr, John; Prausnitz,John; Newman, John


    We have investigated possible anticipated advantages of ionic-liquid electrolytes for use in lithium-ion batteries. Thermal stabilities and phase behavior were studied by thermal gravimetric analysis and differential scanning calorimetry. The ionic liquids studied include various imidazoliumTFSI systems, pyrrolidiniumTFSI, BMIMPF{sub 6}, BMIMBF{sub 4}, and BMIMTf. Thermal stabilities were measured for neat ionic liquids and for BMIMBF{sub 4}-LiBF{sub 4}, BMIMTf-LiTf, BMIMTFSI-LiTFSI mixtures. Conductivities have been measured for various ionic-liquid lithium-salt systems. We show the development of interfacial impedance in a Li|BMIMBF{sub 4} + LiBF{sub 4}|Li cell and we report results from cycling experiments for a Li|BMIMBF{sub 4} + 1 mol/kg LIBF{sub 4}|C cell. The interfacial resistance increases with time and the ionic liquid reacts with the lithium electrode. As expected, imidazolium-based ionic liquids react with lithium electrodes. We seek new ionic liquids that have better chemical stabilities.

  10. Effects of Two Fullerene Derivatives on Monocytes and Macrophages

    PubMed Central

    Pacor, Sabrina; Grillo, Alberto; Đorđević, Luka; Zorzet, Sonia; Da Ros, Tatiana; Prato, Maurizio


    Two fullerene derivatives (fullerenes 1 and 2), bearing a hydrophilic chain on the pyrrolidinic nitrogen, were developed with the aim to deliver anticancer agents to solid tumors. These two compounds showed a significantly different behaviour on human neoplastic cell lines in vitro in respect to healthy leukocytes. In particular, the pyrrolidinium ring on the fullerene carbon cage brings to a more active compound. In the present work, we describe the effects of these fullerenes on primary cultures of human monocytes and macrophages, two kinds of immune cells representing the first line of defence in the immune response to foreign materials. These compounds are not recognized by circulating monocytes while they get into macrophages. The evaluation of the pronecrotic or proapoptotic effects, analysed by means of analysis of the purinergic receptor P2X7 activation and of ROS scavenging activity, has allowed us to show that fullerene 2, but not its analogue fullerene 1, displays toxicity, even though at concentrations higher than those shown to be active on neoplastic cells. PMID:26090460

  11. Synthesis and toxicity evaluation of hydrophobic ionic liquids for volatile organic compounds biodegradation in a two-phase partitioning bioreactor.


    Rodriguez Castillo, Alfredo Santiago; Guihéneuf, Solène; Le Guével, Rémy; Biard, Pierre-François; Paquin, Ludovic; Amrane, Abdeltif; Couvert, Annabelle


    Synthesis of several hydrophobic ionic liquids (ILs), which might be selected as good candidates for degradation of hydrophobic volatile organic compounds in a two-phase partitioning bioreactor (TPPB), were carried out. Several bioassays were also realized, such as toxicity evaluation on activated sludge and zebrafish, cytotoxicity, fluoride release in aqueous phase and biodegradability in order to verify their possible effects in case of discharge in the aquatic environment and/or human contact during industrial manipulation. The synthesized compounds consist of alkylimidazoliums, functionalized imidazoliums, isoqinoliniums, triazoliums, sulfoniums, pyrrolidiniums and morpholiniums and various counter-ions such as: PF6(-), NTf2(-) and NfO(-). Toxicity evaluation on activated sludge of each compound (5% v/v of IL) was assessed by using a glucose uptake inhibition test. Toxicity against zebrafish and cytotoxicity were evaluated by the ImPACCell platform of Rennes (France). Fluoride release in water was estimated by regular measurements using ion chromatography equipment. IL biodegradability was determined by measuring BOD28 of aqueous samples (compound concentration,1mM). All ILs tested were not biodegradable; while some of them were toxic toward activated sludge. Isoquinolinium ILs were toxic to human cancerous cell lines. Nevertheless no toxicity was found against zebrafish Danio rerio. Only one IL released fluoride after long-time agitation. PMID:26785216

  12. Extraction Separation of Rare-Earth Ions via Competitive Ligand Complexations between Aqueous and Ionic-Liquid Phases

    SciTech Connect

    Luo, Huimin; Sun, Xiaoqi; Bell, Jason R; Dai, Sheng


    The extraction separation of rare earth elements is the most challenging separation processes in hydrometallurgy and advanced nuclear fuel cycles. The TALSPEAK process (Trivalent Actinide Lanthanide Separations by Phosphorus-reagent Extraction from Aqueous Komplexes) is a prime example of these separation processes. The objective of this paper is to explore the use of ionic liquids (ILs) for the TALSPEAK-like process, to further enhance its extraction efficiencies for lanthanides, and to investigate the potential of using this modified TALSPEAK process for separation of lanthanides among themselves. Eight imidazolium ILs ([Cnmim][NTf2] and [Cnmim][BETI], n=4,6,8,10) and one pyrrolidinium IL ([C4mPy][NTf2]) were investigated as diluents using di(2-ethylhexyl)phosphoric acid (HDEHP) as an extractant for separation of lanthanide ions from aqueous solutions of 50 mM glycolic acid or citric acid and 5 mM diethylenetriamine pentaacetic acid (DTPA). The extraction efficiencies were studied in comparison with diisopropylbenzene (DIPB), an organic solvent used as diluent for the conventional TALSPEAK extraction system. Excellent extraction efficiencies and selectivities were found for a number of lanthanide ions using HDEHP as an extractant in these ILs. The effects of different alkyl chain lengths in the cations of ILs and anions on extraction efficiencies and selectivities of lanthanide ions are also presented in this paper.

  13. The pharmacological properties of the cholinergic false transmitter, N-2-acetoxyethyl-N-methylpyrrolidinium, and its precursor, N-2-hydroxyethyl-N-methylpyrrolidinium.


    Von Schwarzenfeld, I; Whittaker, V P


    1 The pharmacological properties of N-2-hydroxyethyl-N-methyl pyrrolidinium (pyrrolcholine) and its acetate ester, recently shown to be a false transmitter at the cholinergic electromotor synapses in Torpedo marmorata, also those of the corresponding morpholinium compounds (morpholinecholine, acetylmorpholinecholine) have been studied on the guinea-pig ileum, frog heart, rectus abdominis muscle, rat blood pressure, rat gastrocnemius muscle and dorsal muscle of the leech. 2 Acetylpyrrolcholine and acetylmorpholinecholine are full cholinoceptor agonists with dose-response curves parallel to that of acetylcholine. They are, however, less potent. Acetylpyrrolcholine is relatively more potent as a muscarinic drug (molar potency about 30% of that of acetylcholine in the ileum but only 4% on the leech) whereas acetylmorpholinecholine is more strongly nicotinic. The unacetylated compounds are very weak agonists with potencies comparable to that of choline. 3 Pyrrolcholine in high concentration showed a distinct neuromuscular blocking effect in the rat gastrocnemius muscle preparation. It is likely that this is a direct effect and not due to uptake by the presynaptic nerve terminals followed by conversion to a false transmitter since it was not reduced by hemicholinium-3, which is known to block uptake of choline and choline analogues by the presynaptic high affinity choline uptake system. PMID:837008

  14. Photodetachment, electron cooling, and recombination, in a series of neat aliphatic room temperature ionic liquids.


    Molins i Domenech, Francesc; Healy, Andrew T; Blank, David A


    Transient absorption following photodetachment of a series of neat methyl-alkyl-pyrrolidinium bis(trifluoromethylsulfonyl)amides at 6.20 eV was measured with sub-picosecond time resolution in the visible and near-IR portions of the spectrum. This series spans the onset of structuring in the liquids in the form of polarity alternation. Excitation promotes the electron into a delocalized state with a very large reactive radius. Strong transient absorption is observed in the visible spectrum with a ∼700 fs lifetime, and much weaker, long-lived absorption is observed in the near-IR spectrum. Absorption in the visible is shown to be consistent with the hole, and absorption in the near-IR is assigned to the free solvated electron. Yield of free electrons is estimated at ∼4%, is insensitive to the size of the cation, and is determined in less than 1 ps. Solvation of free electrons depends strongly on the size of the cation and correlates well with the viscosity of the liquid. In addition to radiolytic stability of the aliphatic cations, ultrafast, efficient recombination of separated charge in NTf2 (-) based ionic liquids following photo-excitation near the band-gap may prevent subsequent reactive damage associated with anions. PMID:26277144

  15. Functionalized fullerenes in photodynamic therapy.


    Huang, Ying-Ying; Sharma, Sulbha K; Yin, Rui; Agrawal, Tanupriya; Chiang, Long Y; Hamblin, Michael R


    Since the discovery of C60 fullerene in 1985, scientists have been searching for biomedical applications of this most fascinating of molecules. The unique photophysical and photochemical properties of C60 suggested that the molecule would function well as a photosensitizer in photodynamic therapy (PDT). PDT uses the combination of non-toxic dyes and harmless visible light to produce reactive oxygen species that kill unwanted cells. However the extreme insolubility and hydrophobicity of pristine CO60, mandated that the cage be functionalized with chemical groups that provided water solubility and biological targeting ability. It has been found that cationic quaternary ammonium groups provide both these features, and this review covers work on the use of cationic fullerenes to mediate destruction of cancer cells and pathogenic microorganisms in vitro and describes the treatment of tumors and microbial infections in mouse models. The design, synthesis, and use of simple pyrrolidinium salts, more complex decacationic chains, and light-harvesting antennae that can be attached to C60, C70 and C84 cages are covered. In the case of bacterial wound infections mice can be saved from certain death by fullerene-mediated PDT. PMID:25544837

  16. Functionalized Fullerenes in Photodynamic Therapy

    PubMed Central

    Huang, Ying-Ying; Sharma, Sulbha K.; Yin, Rui; Agrawal, Tanupriya; Chiang, Long Y.; Hamblin, Michael R.


    Since the discovery of C60 fullerene in 1985, scientists have been searching for biomedical applications of this most fascinating of molecules. The unique photophysical and photochemical properties of C60 suggested that the molecule would function well as a photosensitizer in photodynamic therapy (PDT). PDT uses the combination of non-toxic dyes and harmless visible light to produce reactive oxygen species that kill unwanted cells. However the extreme insolubility and hydrophobicity of pristine C60, mandated that the cage be functionalized with chemical groups that provided water solubility and biological targeting ability. It has been found that cationic quaternary ammonium groups provide both these features, and this review covers work on the use of cationic fullerenes to mediate destruction of cancer cells and pathogenic microorganisms in vitro and describes the treatment of tumors and microbial infections in mouse models. The design, synthesis, and use of simple pyrrolidinium salts, more complex decacationic chains, and light-harvesting antennae that can be attached to C60, C70 and C84 cages are covered. In the case of bacterial wound infections mice can be saved from certain death by fullerene-mediated PDT. PMID:25544837

  17. Inhibition of ( sup 3 H)dopamine uptake into rat striatal slices by quaternary N-methylated nicotine metabolites

    SciTech Connect

    Dwoskin, L.P.; Leibee, L.L.; Jewell, A.L.; Fang, Zhaoxia; Crooks, P.A. )


    The effects of quaternary N-methylated nicotine derivatives were examined on in vitro uptake of ({sup 3}H)dopamine (({sup 3}H)DA) in rat striatal slices. Striatal slices were incubated with a 10 {mu}M concentration of the following compounds: N-methylnicotinium, N-methylnornicotinium, N-methylcotininium, N,N{prime}-dimethylnicotinium and N{prime}-methylnicotinium salts. The results clearly indicated that significant inhibition of ({sup 3}H)DA uptake occurred with those compounds possessing a N-methylpyridinium group; whereas, compounds that were methylated at the N{prime}-pyrrolidinium position were less effective or exhibited no inhibition of ({sup 3}H)DA uptake. The results suggest that high concentrations of quaternary N-methylated nicotine metabolites which are structurally related to the neurotoxin MPP{sup +}, and which may be formed in the CNS, may protect against Parkinson's Disease and explain the inverse relationship between smoking and Parkinsonism reported in epidemiologic studies.

  18. Ionic liquids as antiwear additives in base oils: influence of structure on miscibility and antiwear performance for steel on aluminum.


    Somers, Anthony E; Khemchandani, Bhawna; Howlett, Patrick C; Sun, Jiazeng; MacFarlane, Douglas R; Forsyth, Maria


    The use of ionic liquids as additives to base oil for the lubrication of steel on aluminum was investigated. The miscibility and wear performance of various phosphonium, imidazolium, and pyrrolidinium ionic liquids in a range of polar and nonpolar base oils was determined. The structure and ion pairing of the ionic liquids was found to be important in determining their miscibility in the base oils. In wear tests, some of the miscible base oil/IL blends reduced the aluminum wear depth when compared to that found with the base oil alone. The nonpolar base oil/IL blends were able to withstand higher wear-test loads than the polar base oil/IL blends. At 10 N, as little as 0.01 mol/kg of IL, or 0.7-0.9 wt %, in the nonpolar base oils was enough to drastically reduce the wear depth on the aluminum. XPS analysis of the wear surfaces suggested that the adsorbing of the IL to the surface, where it can form low-shear layers and also react to form tribofilms, is important in reducing friction and wear. The largest reductions in wear at the highest load tested were found for a mineral oil/P6,6,6,14 (i)(C8)2PO2 blend. PMID:24187923

  19. Methane-oxygen electrochemical coupling in an ionic liquid: a robust sensor for simultaneous quantification.


    Wang, Zhe; Guo, Min; Baker, Gary A; Stetter, Joseph R; Lin, Lu; Mason, Andrew J; Zeng, Xiangqun


    Current sensor devices for the detection of methane or natural gas emission are either expensive and have high power requirements or fail to provide a rapid response. This report describes an electrochemical methane sensor utilizing a non-volatile and conductive pyrrolidinium-based ionic liquid (IL) electrolyte and an innovative internal standard method for methane and oxygen dual-gas detection with high sensitivity, selectivity, and stability. At a platinum electrode in bis(trifluoromethylsulfonyl)imide (NTf2)-based ILs, methane is electro-oxidized to produce CO2 and water when an oxygen reduction process is included. The in situ generated CO2 arising from methane oxidation was shown to provide an excellent internal standard for quantification of the electrochemical oxygen sensor signal. The simultaneous quantification of both methane and oxygen in real time strengthens the reliability of the measurements by cross-validation of two ambient gases occurring within a single sample matrix and allows for the elimination of several types of random and systematic errors in the detection. We have also validated this IL-based methane sensor employing both conventional solid macroelectrodes and flexible microfabricated electrodes using single- and double-potential step chronoamperometry. PMID:25093213

  20. Nonhumidified intermediate temperature fuel cells using protic ionic liquids.


    Lee, Seung-Yul; Ogawa, Atsushi; Kanno, Michihiro; Nakamoto, Hirofumi; Yasuda, Tomohiro; Watanabe, Masayoshi


    In this paper, the characterization of a protic ionic liquid, diethylmethylammonium trifluoromethanesulfonate ([dema][TfO]), as a proton conductor for a fuel cell and the fabrication of a membrane-type fuel cell system using [dema][TfO] under nonhumidified conditions at intermediate temperatures are described in detail. In terms of physicochemical and electrochemical properties, [dema][TfO] exhibits high activity for fuel cell electrode reactions (i.e., the hydrogen oxidation reaction (HOR) and oxygen reduction reaction (ORR)) at a Pt electrode, and the open circuit voltage (OCV) of a liquid fuel cell is 1.03 V at 150 degrees C, as has reported in ref 27. However, diethylmethylammonium bis(trifluoromethane sulfonyl)amide ([dema][NTf(2)]) has relatively low HOR and ORR activity, and thus, the OCV is ca. 0.7 V, although [dema][NTf(2)] and [dema][TfO] have an identical cation ([dema]) and similar thermal and bulk-transport properties. Proton conduction occurs mainly via the vehicle mechanism in [dema][TfO] and the proton transference number (t(+)) is 0.5-0.6. This relatively low t(+) appears to be more disadvantageous for a proton conductor than for other electrolytes such as hydrated sulfonated polymer electrolyte membranes (t(+) = 1.0). However, fast proton-exchange reactions occur between ammonium cations and amines in a model compound. This indicates that the proton-exchange mechanism contributes to the fuel cell system under operation, where deprotonated amines are continuously generated by the cathodic reaction, and that polarization of the cell is avoided. Six-membered sulfonated polyimides in the diethylmethylammonium form exhibit excellent compatibility with [dema][TfO]. The composite membranes can be obtained up to a [dema][TfO] content of 80 wt % and exhibit good thermal stability, high ionic conductivity, and mechanical strength and gas permeation comparable to those of hydrated Nafion. H(2)/O(2) fuel cells prepared using the composite membranes can successfully operate at temperatures from 30 to 140 degrees C under nonhumidified conditions, and a current density of 250 mA cm(-2) is achieved at 120 degrees C. The protic ionic liquid and its composite membrane are a possible candidate for an electrolyte of a H(2)/O(2) fuel cell that operates under nonhumidified conditions. PMID:20578771

  1. Ionic liquid-assisted sonochemical preparation of CeO2 nanoparticles for CO oxidation

    SciTech Connect

    Alammar, Tarek; Noei, Heshmat; Wang, Yuemin; Grünert, Wolfgang; Mudring, Anja -Verena


    CeO2 nanoparticles were synthesized via a one-step ultrasound synthesis in different kinds of ionic liquids based on bis(trifluoromethanesulfonylamide, [Tf2N], in combination with various cations including 1-butyl-3-methylimidazolium ([C4mim]+), 1-ethyl-2,3-dimethylimidazolium ([Edimim]+), butyl-pyridinium([Py4]+), 1-butyl-1-methyl-pyrrolidinium ([Pyrr14]+), and 2-hydroxyethyl-trimethylammonium ([N1112OH]+). Depending on synthetic parameters, such as ionic liquid, Ce(IV) precursor, heating method, and precipitator, formed ceria exhibits different morphologies, varying from nanospheres, nanorods, nanoribbons, and nanoflowers. The morphology, crystallinity, and chemical composition of the obtained materials were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDX), Raman spectroscopy, and N2 adsorption. The structural and electronic properties of the as-prepared CeO2 samples were probed by CO adsorption using IR spectroscopy under ultrahigh vacuum conditions. The catalytic activities of CeO2 nanoparticles were investigated in the oxidation of CO. CeO2 nanospheres obtained sonochemically in [C4mim][Tf2N] exhibit the best performance for low-temperature CO oxidation. As a result, the superior catalytic performance of this material can be related to its mesoporous structure, small particle size, large surface area, and high number of surface oxygen vacancy sites.

  2. Inhibiting activities of the secondary metabolites of Phlomis brunneogaleata against parasitic protozoa and plasmodial enoyl-ACP Reductase, a crucial enzyme in fatty acid biosynthesis.


    Kirmizibekmez, Hasan; Calis, Ihsan; Perozzo, Remo; Brun, Reto; Dnmez, Ali A; Linden, Anthony; Redi, Peter; Tasdemir, Deniz


    Anti-plasmodial activity-guided fractionation of Phlomis brunneogaleata (Lamiaceae) led to the isolation of two new metabolites, the iridoid glycoside, brunneogaleatoside and a new pyrrolidinium derivative (2 S,4 R)-2-carboxy-4-( E)- p-coumaroyloxy-1,1-dimethylpyrrolidinium inner salt [(2 S,4 R)-1,1-dimethyl-4-( E)- p-coumaroyloxyproline inner salt]. Moreover, a known iridoid glycoside, ipolamiide, six known phenylethanoid glycosides, verbascoside, isoverbascoside, forsythoside B, echinacoside, glucopyranosyl-(1-->G (i)-6)-martynoside and integrifolioside B, two flavone glycosides, luteolin 7- O-beta- D-glucopyranoside ( 10) and chrysoeriol 7- O-beta- D-glucopyranoside ( 11), a lignan glycoside liriodendrin, an acetophenone glycoside 4-hydroxyacetophenone 4- O-(6'- O-beta- D-apiofuranosyl)-beta- D-glucopyranoside and three caffeic acid esters, chlorogenic acid, 3-O-caffeoylquinic acid methyl ester and 5- O-caffeoylshikimic acid were isolated. The structures of the pure compounds were elucidated by means of spectroscopic methods (UV, IR, MS, 1D and 2D NMR, [alpha] (D)) and X-ray crystallography. Compounds 10 and 11 were determined to be the major anti-malarial principles of the crude extract (IC (50) values of 2.4 and 5.9 micrograms/mL, respectively). They also exhibited significant leishmanicidal activity (IC (50) = 1.1 and 4.1 micrograms/mL, respectively). The inhibitory potential of the pure metabolites against plasmodial enoyl-ACP reductase (FabI), which is the key regulator of type II fatty acid synthases (FAS-II) in P. falciparum, was also assessed. Compound 10 showed promising FabI inhibiting effect (IC (50) = 10 micrograms/mL) and appears to be the first anti-malarial natural product targeting FabI of P. falciparum. PMID:15326547

  3. Designer Ionic Liquids for Reversible Electrochemical Deposition/Dissolution of Magnesium.


    Watkins, Tylan; Kumar, Ashok; Buttry, Daniel A


    Chelating ionic liquids (ILs), in which polyether chains are pendent from the organic pyrrolidinium cation of the ILs (PEGylated ILs), were prepared that facilitate reversible electrochemical deposition/dissolution of Mg from a Mg(BH4)2 source. Mg electrodeposition processes in two specific PEGylated-ILs were compared against that in the widely studied N-butyl-N-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ionic liquid (BMPyrTFSI). The two chelating IL systems (one with a pendent polyether chain with three ether oxygens, MPEG3PyrTFSI, and the other with a seven-ether chain, MPEG7PyrTFSI) showed substantial improvement over BMPyrTFSI for Mg electrodeposition/dissolution. The best overall electrochemical performance was in MPEG7PyrTFSI. X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS) were used to characterize galvanostatically deposited Mg, revealing production of pure, dendrite-free Mg deposits. Reversible Mg electrodeposition was achieved with high Coulombic efficiency (CE) of 90% and high current density (ca. 2 mA/cm(2) for the stripping peak). Raman spectroscopy was used to characterize Mg(2+) speciation in the PEGylated ILs and BMPyrTFSI containing Mg(BH4)2 by study of Raman modes of the coordinated and free states of borohydride, TFSI(-), and polyether COC groups. Quantitative analysis revealed that the polyether chains can displace both TFSI(-) and BH4(-) from the coordination sphere of Mg(2+). Comparison of the different IL electrolytes suggested that these displacement reactions may play a role in enabling Mg deposition/dissolution with high CE and current density in these PEGylated IL media. These results represent the first demonstration of reversible electrochemical deposition/dissolution of Mg in an ionic liquid specifically designed with this task in mind. PMID:26683518

  4. Electrodeposition of Al in 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ionic liquids: in situ STM and EQCM studies.


    Moustafa, E M; El Abedin, S Zein; Shkurankov, A; Zschippang, E; Saad, A Y; Bund, A; Endres, F


    In the present paper, the electrodeposition of Al on flame-annealed Au(111) and polycrystalline Au substrates in two air- and water-stable ionic liquids namely, 1-butyl-1-methyl-pyrrolidinium bis(trifluoromethylsulfonyl)amide, [Py(1,4)]Tf(2)N, and 1-ethyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)amide, [EMIm]Tf(2)N, has been investigated by in situ scanning tunneling microscopy (STM), electrochemical quartz crystal microbalance (EQCM), and cyclic voltammetry. The cyclic voltammogram of aluminum deposition and stripping on Au(111) in the upper phase of the biphasic mixture of AlCl(3)/[EMIm]Tf(2)N at room temperature (25 degrees C) shows that the electrodeposition process is completely reversible as also evidenced by in situ STM and EQCM studies. Additionally, a cathodic peak at an electrode potential of about 0.55 V vs Al/Al(III) is correlated to the aluminum UPD process that was evidenced by in situ STM. A surface alloying of Al with Au at the early stage of deposition occurs. It has been found that the Au(111) surface is subject to a restructuring/reconstruction in the upper phase of the biphasic mixture of AlCl(3)/[Py(1,4)]Tf(2)N at room temperature (25 degrees C) and that the deposition is not fully reversible. Furthermore, the underpotential deposition of Al in [Py(1,4)]Tf(2)N is not as clear as in [EMIm]Tf(2)N. The frequency shift in the EQCM experiments in [Py(1,4)]Tf(2)N shows a surprising result as an increase in frequency and a decrease in damping with bulk aluminum deposition at potentials more negative than -1.8 V was observed at room temperature. However, at 100 degrees C there is a frequency decrease with ongoing Al deposition. At -2.0 V vs Al/Al(III), a bulk aluminum deposition sets in. PMID:17388503

  5. Protic ionic liquids with fluorous anions: physicochemical properties and self-assembly nanostructure.


    Shen, Yan; Kennedy, Danielle F; Greaves, Tamar L; Weerawardena, Asoka; Mulder, Roger J; Kirby, Nigel; Song, Gonghua; Drummond, Calum J


    A series of 11 new protic ionic liquids with fluorous anions (FPILs) have been identified and their self-assembled nanostructure, thermal phase transitions and physicochemical properties were investigated. To the best of our knowledge this is the first time that fluorocarbon domains have been reported in PILs. The FPILs were prepared from a range of hydrocarbon alkyl and heterocyclic amine cations in combination with the perfluorinated anions heptafluorobutyrate and pentadecafluorooctanoate. The nanostructure of the FPILs was established by using small- and wide-angle X-ray scattering (SAXS and WAXS). In the liquid state many of the FPILs showed an intermediate range order, or self-assembled nanostructure, resulting from segregation of the polar and nonpolar hydrocarbon and fluorocarbon domains of the ionic liquid. In addition, the physicochemical properties of the FPILs were determined including the melting point (T(m)), glass transition (T(g)), devitrification temperature (T(c)), thermal stability and the density ?, viscosity ?, air/liquid surface tension ?(LV), refractive index n(D), and ionic conductivity ?. The FPILs were mostly solids at room temperature, however two examples 2-pyrrolidinonium heptafluorobutyrate (PyrroBF) and pyrrolidinium heptafluorobutyrate (PyrrBF) were liquids at room temperature and all of the FPILs melted below 80 C. Four of the FPILs exhibited a glass transition. The two liquids at room temperature, PyrroBF and PyrrBF, had a similar density, surface tension and refractive index but their viscosity and ionic conductivity were very different due to dissimilar self-assembled nanostructure. PMID:22569799

  6. Meta-analysis of ionic liquid literature and toxicology.


    Heckenbach, Mary E; Romero, Felicia N; Green, Matthew D; Halden, Rolf U


    A meta-analysis was conducted to compare the total amount of ionic liquid (IL) literature (n = 39,036) to the body of publications dealing with IL toxicity (n = 213) with the goal of establishing the state of knowledge and existing information gaps. Additionally, patent literature pertaining to issued patents utilizing ILs (n = 3358) or dealing with IL toxicity (n = 112) were analyzed. Total publishing activity and patent count served to gauge research activity, industrial usage and toxicology knowledge of ILs. Five of the most commonly studied IL cations were identified and used to establish a relationship between toxicity data and potential of commercial use: imidazolium, ammonium, phosphonium, pyridinium, and pyrrolidinium. Toxicology publications for all IL cations represented 0.55% ± 0.27% of the total publishing activity; compared with other industrial chemicals, these numbers indicate that there is still a paucity of studies on the adverse effects of this class of chemical. Toxicity studies on ILs were dominated by the use of in vitro models (18%) and marine bacteria (15%) as studied biological systems. Whole animal studies (n = 87) comprised 31% of IL toxicity studies, with a subset of in vivo mammalian models consisting of 8%. Human toxicology data were found to be limited to in vitro analyses, indicating substantial knowledge gaps. Risks from long-term and chronic low-level exposure to ILs have not been established yet for any model organisms, reemphasizing the need to fill crucial knowledge gaps concerning human health effects and the environmental safety of ILs. Adding to the existing knowledge of the molecular toxicity characteristics of ILs can help inform the design of greener, less toxic and more benign IL technologies. PMID:26907595

  7. Solvation and rotational dynamics of coumarin 153 in ionic liquids: comparisons to conventional solvents.


    Jin, Hui; Baker, Gary A; Arzhantsev, Sergei; Dong, Jing; Maroncelli, Mark


    Steady-state and time-resolved emission spectroscopy with 25 ps resolution are used to measure equilibrium and dynamic aspects of the solvation of coumarin 153 (C153) in a diverse collection of 21 room-temperature ionic liquids. The ionic liquids studied here include several phosphonium and imidazolium liquids previously reported as well as 12 new ionic liquids that incorporate two homologous series of ammonium and pyrrolidinium cations. Steady-state absorption and emission spectra are used to extract solvation free energies and reorganization energies associated with the S0 <--> S1 transition of C153. These quantities, especially the solvation free energy, vary relatively little in ionic liquids compared to conventional solvents. Some correlation is found between these quantities and the mean separation between ions (or molar volume). Time-resolved anisotropies are used to observe solute rotation. Rotation times measured in ionic liquids correlate with solvent viscosity in much the same way that they do in conventional polar solvents. No special frictional coupling between the C153 and the ionic liquid solvents is indicated by these times. But, in contrast to what is observed in most low-viscosity conventional solvents, rotational correlation functions in ionic liquids are nonexponential. Time-resolved Stokes shift measurements are used to characterize solvation dynamics. The solvation response functions in ionic liquids are also nonexponential and can be reasonably represented by stretched-exponential functions of time. The solvation times observed are correlated with the solvent viscosity, and the much slower solvation in ionic liquids compared to dipolar solvents can be attributed to their much larger viscosities. Solvation times of the majority of ionic liquids studied appear to follow a single correlation with solvent viscosity. Only liquids incorporating the largest phosphonium cation appear to follow a distinctly different correlation. PMID:17530885

  8. Ionic Liquids as Electrolytes for Electrochemical Double-Layer Capacitors: Structures that Optimize Specific Energy.


    Mousavi, Maral P S; Wilson, Benjamin E; Kashefolgheta, Sadra; Anderson, Evan L; He, Siyao; Bühlmann, Philippe; Stein, Andreas


    Key parameters that influence the specific energy of electrochemical double-layer capacitors (EDLCs) are the double-layer capacitance and the operating potential of the cell. The operating potential of the cell is generally limited by the electrochemical window of the electrolyte solution, that is, the range of applied voltages within which the electrolyte or solvent is not reduced or oxidized. Ionic liquids are of interest as electrolytes for EDLCs because they offer relatively wide potential windows. Here, we provide a systematic study of the influence of the physical properties of ionic liquid electrolytes on the electrochemical stability and electrochemical performance (double-layer capacitance, specific energy) of EDLCs that employ a mesoporous carbon model electrode with uniform, highly interconnected mesopores (3DOm carbon). Several ionic liquids with structurally diverse anions (tetrafluoroborate, trifluoromethanesulfonate, trifluoromethanesulfonimide) and cations (imidazolium, ammonium, pyridinium, piperidinium, and pyrrolidinium) were investigated. We show that the cation size has a significant effect on the electrolyte viscosity and conductivity, as well as the capacitance of EDLCs. Imidazolium- and pyridinium-based ionic liquids provide the highest cell capacitance, and ammonium-based ionic liquids offer potential windows much larger than imidazolium and pyridinium ionic liquids. Increasing the chain length of the alkyl substituents in 1-alkyl-3-methylimidazolium trifluoromethanesulfonimide does not widen the potential window of the ionic liquid. We identified the ionic liquids that maximize the specific energies of EDLCs through the combined effects of their potential windows and the double-layer capacitance. The highest specific energies are obtained with ionic liquid electrolytes that possess moderate electrochemical stability, small ionic volumes, low viscosity, and hence high conductivity, the best performing ionic liquid tested being 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide. PMID:26771378

  9. The effect of the cation alkyl chain branching on mutual solubilities with water and toxicities

    PubMed Central

    Kurnia, Kiki A.; Sintra, Tânia E.; Neves, Catarina M. S. S.; Shimizu, Karina; Lopes, José N. Canongia; Gonçalves, Fernando; Ventura, Sónia P. M.; Freire, Mara G.; Santos, Luís M. N. B. F.; Coutinho, João A. P.


    The design of ionic liquids has been focused on the cation-anion combinations but other more subtle approaches can be used. In this work the effect of the branching of the cation alkyl chain on the design of ionic liquids (ILs) is evaluated. The mutual solubilities with water and toxicities of a series of bis(trifluoromethylsulfonyl)-based ILs, combined with imidazolium, pyridinium, pyrrolidinium, and piperidinium cations with linear or branched alkyl chains, are reported. The mutual solubility measurements were carried out in the temperature range from (288.15 to 323.15) K. From the obtained experimental data, the thermodynamic properties of the solution (in the water-rich phase) were determined and discussed. The COnductor like Screening MOdel for Real Solvents (COSMO-RS) was used to predict the liquid-liquid equilibrium. Furthermore, molecular dynamic simulations were also carried out aiming to get a deeper understanding of these fluids at the molecular level. The results show that the increase in the number of atoms at the cation ring (from five to six) leads to a decrease in the mutual solubilities with water while increasing their toxicity, and as expected from the well-established relationship between toxicities and hydrophobicities of ILs. The branching of the alkyl chain was observed to decrease the water solubility in ILs, while increasing the ILs solubility in water. The inability of COSMO-RS to correctly predict the effect of branching alkyl chains toward water solubility on them was confirmed using molecular dynamic simulations to be due to the formation of nano-segregated structures of the ILs that are not taken into account by the COSMO-RS model. In addition, the impact of branched alkyl chains on the toxicity is shown to be not trivial and to depend on the aromatic nature of the ILs. PMID:25119425

  10. Cationic gemini surfactants as pseudostationary phases in micellar electrokinetic chromatography. Part I: effect of head group.


    Akbay, Cevdet; Hoyos, Yatzka; Hooper, Edward; Arslan, Hakan; Rizvi, Syed A A


    Two cationic gemini surfactants with pyrrolidinium or alkyl ammonium head groups with but-2-yne spacers, but with the same length hydrocarbon chain have been characterized with respect to their aggregation behaviors and separation power as pseudostationary phases (PSPs) for micellar electrokinetic chromatography (MEKC). They were compared with a commonly used PSP, sodium dodecylsulfate (SDS). The results suggest that the head groups of the surfactants have some effect on physicochemical properties such as critical micelle concentration (CMC), C(20), gamma(CMC), partial specific volume, methylene selectivity and mobilities of the surfactants. CMC values of G1, G2 and SDS in pure water were found to be 0.82, 0.71, and 8.08 mM, respectively; they were reduced to 0.21, 0.11, and 3.0 mM when measured in 10 mM phosphate buffer at pH 7.0. G1 (alphaCH2 = 2.74) and G2 (alphaCH2 = 2.48) provided the most and the least hydrophobic environment, respectively. According to their partial specific volumes, geminis were found to have more flexible structures as compared with sodium dodecylsulfate. The effects of the head group structure were also characterized with the linear solvation energy relationship (LSER) model, which was able to evaluate the role of solute size, polarity/polarizability, and hydrogen bonding on retention and selectivity. The cohesiveness, hydrogen bond acidic and basic character of the surfactant systems were found to have the most significant influence on selectivity and MEKC retention of the gemini surfactants. It should be noted that with their large positive coefficient a values, G1 and G2 were found to be stronger HB acceptors than anionic and most of the cationic surfactants studied in the literature. PMID:20598697

  11. Phase behaviour, transport properties, and interactions in Li-salt doped ionic liquids.


    Pitawala, Jagath; Kim, Jae-Kwang; Jacobsson, Per; Koch, Victor; Croce, Fausto; Matic, Aleksandar


    We report on the influence of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) doping on the glass transition temperature (Tg), the ionic conductivity, and Li-ion coordination of two dicationic ionic liquids (DILs) based on the TFSI anion. The results are compared to the behaviour of traditional mono-cationic ionic liquids. The cations of the DILs contain two imidazolium rings, connected by a decane hydrocarbon chain. Homogeneous mixtures of these ILs and LiTFSI can be obtained in a large concentration range. With increasing Li-salt concentration the ionic conductivity decreases whereas the glass transition temperature increases in both systems. However, the influence of the salt doping on the ionic conductivity and the glass transition temperature is low compared to typical mono-cationic ionic liquids, based on for example the pyrrolidinium cation and the TFSI anion. This behaviour is mirrored in the average coordination number of TFSI anions around Li-ions, determined by Raman spectroscopy. The coordination number is systematically lower in the DILs, suggesting a connection between the difference in the Li-ion environment and the behaviour of the glass transition and the ionic conductivity. A Tg-scaled Arrhenius plot of the ionic conductivity shows that the ionic conductivity for all LiTFSI concentrations has the same temperature dependence, i.e., the fragility of the liquid is the same. This implies that the conduction process is dominated by the viscous properties of the liquids over the entire concentration range. This provides further support for linking the local environment of the Li-ions to the glass transition and conduction process in the ionic liquid/salt mixtures. PMID:22455015

  12. Aqueous biphasic systems composed of ionic liquids and sodium carbonate as enhanced routes for the extraction of tetracycline.


    Marques, Carlos F C; Mouro, Teresa; Neves, Catarina M S S; Lima, Alvaro S; Boal-Palheiros, Isabel; Coutinho, Joo A P; Freire, Mara G


    Aqueous biphasic systems (ABS) using ionic liquids (ILs) offer an alternative approach for the extraction, recovery, and purification of biomolecules through their partitioning between two aqueous liquid phases. In this work, the ability of a wide range of ILs to form ABS with aqueous solutions of Na2 CO3 was evaluated. The ABS formed by IL?+?water?+?Na2 CO3 were determined at 25C, and the respective solubility curves, tie-lines, and tie-line lengths are reported. The studied ILs share the common chloride anion, allowing the IL cation core, the cation isomerism, the presence of functionalized groups, and alkyl side chain length effects to be evaluated. An increase in the cation side alkyl chain length leads to a higher ability for liquid-liquid demixing whereas different positional isomers and the presence of an allyl group have no major influence in the phase diagrams behavior. Quaternary phosphonium- and ammonium-based fluids are more able to form an ABS when compared with imidazolium-, pyridinium-, pyrrolidinium-, and piperidium-based ILs. Moreover, the presence of an aromatic cation core has no major contribution to the formation of ABS when compared to the respective nonaromatic counterparts. Finally, to appraise on the systems applicability in downstream processing, selected systems were used for the partitioning of tetracyclines (neutral and salt forms) - a class of antibiotics produced by bacteria fermentation. Single-step extraction efficiencies for the IL-rich phase were always higher than 99% and confirm the great potential of ILs to be applied in the biotechnological field. PMID:23420737

  13. Functionalized fullerenes mediate photodynamic killing of cancer cells: Type I versus Type II photochemical mechanism

    PubMed Central

    Mroz, Pawel; Pawlak, Anna; Satti, Minahil; Lee, Haeryeon; Wharton, Tim; Gali, Hariprasad; Sarna, Tadeusz; Hamblin, Michael R.


    Photodynamic therapy (PDT) employs the combination of non-toxic photosensitizers (PS) and harmless visible light to generate reactive oxygen species (ROS) and kill cells. Most clinically studied PS are based on the tetrapyrrole structure of porphyrins, chlorins and related molecules, but new non-tetrapyrrole PS are being sought. Fullerenes are soccer-ball shaped molecules composed of sixty or seventy carbon atoms and have attracted interest in connection with the search for biomedical applications of nanotechnology. Fullerenes are biologically inert unless derivatized with functional groups, whereupon they become soluble and can act as PS. We have compared the photodynamic activity of six functionalized fullerenes with 1, 2, or 3 hydrophilic or 1, 2, or 3 cationic groups. The octanol-water partition coefficients were determined and the relative contributions of Type I photochemistry (photogeneration of superoxide in the presence of NADH) and Type II photochemistry (photogeneration of singlet oxygen) were studied by measurement of oxygen consumption, 1270-nm luminescence and EPR spin-trapping of the superoxide product. We studied three mouse cancer cell lines: (J774, LLC and CT26) incubated for 24 h with fullerenes and illuminated with white light. The order of effectiveness as PS was inversely proportional to the degree of substitution of the fullerene nucleus for both the neutral and cationic series. The mono-pyrrolidinium fullerene was the most active PS against all cell lines and induced apoptosis 46 hours after illumination. It produced diffuse intracellular fluorescence when dichlorodihydrofluorescein was added as an ROS probe suggesting a Type I mechanism for phototoxicity. We conclude that certain functionalized fullerenes have potential as novel PDT agents and phototoxicity may be mediated both by superoxide and by singlet oxygen. PMID:17664135

  14. Effects of Aromaticity in Cations and Their Functional Groups on the Low-Frequency Spectra and Physical Properties of Ionic Liquids.


    Shirota, Hideaki; Matsuzaki, Hironori; Ramati, Sharon; Wishart, James F


    We have critically investigated the low-frequency spectra of six ionic liquids (ILs) consisting of systematically different cations having benzyl moieties or comparable-sized saturated cyclohexylmethyl groups, by means of femtosecond Raman-induced Kerr effect spectroscopy (fs-RIKES). The target ionic liquids are bis(trifluoromethylsulfonyl)amide ([NTf2](-)) salts of the 1-benzyl-3-methylimidazolium ([BzMIm](+)), 1-benzyl-1-methylpyrrolidinium ([BzMPyrr](+)), 1-benzylpyridinium ([BzPy](+)), 1-cyclohexylmethyl-3-methylimidazolium ([CHxmMIm](+)), 1-cyclohexylmethyl-1-methylpyrrolidinium ([CHxmMPyrr](+)), and 1-cyclohexylmethylpyridinium ([CHxmPy](+)) cations. The primary purpose of this study is to clarify the effects of charged and neutral aromatic moieties on the low-frequency spectrum and bulk properties such as liquid density, surface tension, shear viscosity, glass transition temperature, and melting point. We found that ILs with benzyl groups have larger surface tensions than those with the same cation bearing the cyclohexylmethyl group. The trend in the glass transition temperatures, comparing ILs having the same side group, is pyridinium > imidazolium > pyrrolidinium. The effects of a single aromatic moiety on the shear viscosity are inconclusive, although the viscosities of the ILs with aromatic moieties on both the cation and the benzyl group, i.e., [BzMIm][NTf2] and [BzPy][NTf2], are substantially lower than those of the other ILs at room temperature, as a consequence of their higher fragilities. In the low-frequency Kerr spectra in the frequency range of approximately 0.1 to 200 cm(-1) measured by fs-RIKES, the ILs possessing two aromatic groups show the largest relative intensity of the nuclear response to the electronic response. Both the charged and neutral aromatic rings show signals due to the ring libration; the neutral one appears at a lower frequency than the charged one. The relationship between the first moment of the broad low-frequency spectrum band and the bulk parameter consisting of the square root of the surface tension divided by the liquid density is obeyed by the cyclohexylmethyl derivatives whether the cation is aromatic or not, but not by the ILs with the neutral aromatic benzyl group. Quantum chemistry calculations have been also performed to understand the vibrational modes of the ionic species in the ILs. PMID:25389916

  15. Influence of structural variations in cationic and anionic moieties on the polarity of ionic liquids.


    Chiappe, Cinzia; Pomelli, Christian Silvio; Rajamani, Sunita


    The polarity of a series of ionic liquids (ILs) arising from the quaternarization of N-methylmorpholine, N-methylpyrrolidine, N-methylpiperidine, N-methylazepane, 4-hydroxy-1-methylpiperidine, 1,2-dimethylimidazole, and 1-methylimidazole with simple alkyl chains and/or hydroxyl (mono- or dihydroxyl) functionalized alkyl chains and having bistriflimide, dicyanamide, or nitrate as counteranions has been investigated using solvatochromic dyes and expressed in terms of E(T)(N) and Kamlet-Taft parameters (dipolarity/polarizability (π*), hydrogen bond donor acidity (α), and hydrogen bond basicity (β)). Significant variations of polarity were observed on changing the anion and cation combination. The resulting E(T)(N) and α values were strongly anion dependent; on going from bistriflimide to dicyanamide, a significant decrease in E(T)(N) and α values was observed. On the other hand, the alkyl chain length has only a moderate effect on these parameters; either an increase or decrease in E(T)(N) and α values was observed on increasing the alkyl chain length, depending on the cation core. In the case of cyclic onium salts, the size of the cation ring affected the α parameter; the ILs based on the seven-membered ring system N-methyl-N-butylazepanium (also named N-methyl-N-butylhexamethyleneiminium, [HME(1,4)](+)) have high polarity values, comparatively to the ILs based on analogous five- and six-membered cyclic cations (pyrrolidinium and piperidinium). The introduction of the OH groups on the cation alkyl chain increases the polarity; the effect is substantial for the first OH group and more moderate for the second. Also, the thermosolvatochromism (changes in solvatochromic properties with the change in temperature) was studied for four dihydroxyl functionalized ILs. Finally, the principal component analysis (PCA) carried out on 67 ILs has shown that there are only two statistically relevant parameters: PC1, a weighted sum of E(T)(N) and α, which is able to discern between the cation core structure, functionalization, and cation-anion association, and PC2, very close to β, which is related principally to the anion nature. PMID:21721537

  16. Designed Chemical Intervention with Thiols for Prophylactic Contraception

    PubMed Central

    Jain, Ashish; Verma, Vikas; Sharma, Vikas; Kushwaha, Bhavana; Lal, Nand; Kumar, Lalit; Rawat, Tara; Dwivedi, Anil K.; Maikhuri, Jagdamba P.; Sharma, Vishnu L.; Gupta, Gopal


    Unlike somatic cells, sperm have several-fold more available-thiols that are susceptible to redox-active agents. The present study explains the mechanism behind the instant sperm-immobilizing and trichomonacidal activities of pyrrolidinium pyrrolidine-1-carbodithioate (PPC), a novel thiol agent rationally created for prophylactic contraception by minor chemical modifications of some known thiol drugs. PPC, and its three derivatives (with potential active-site blocked by alkylation), were synthesized and evaluated against live human sperm and metronidazole-susceptible and resistant Trichomonas vaginalis, in vitro. Sperm hexokinase activity was evaluated by coupled enzyme assay. PPC irreversibly immobilized 100% human sperm in ∼30 seconds and totally eliminated Trichomonas vaginalis more efficiently than nonoxynol-9 and metronidazole. It significantly inhibited (P<0.001) thiol-sensitive sperm hexokinase. However, the molecule completely lost all its biological activities once its thiol group was blocked by alkylation. PPC was subsequently formulated into a mucoadhesive vaginal film using GRaS excipients and evaluated for spermicidal and microbicidal activities (in vitro), and contraceptive efficacy in rabbits. PPC remained fully active in quick-dissolving, mucoadhesive vaginal-film formulation, and these PPC-films significantly reduced pregnancy and fertility rates in rabbits. The films released ∼90% of PPC in simulated vaginal fluid (pH 4.2) at 37°C in 5 minutes, in vitro. We have thus discovered a common target (reactive thiols) on chiefly-anaerobic, redox-sensitive cells like sperm and Trichomonas, which is susceptible to designed chemical interference for prophylactic contraception. The active thiol in PPC inactivates sperm and Trichomonas via interference with crucial sulfhydryl-disulfide based reactions, e.g. hexokinase activation in human sperm. In comparison to non-specific surfactant action of OTC spermicide nonoxynol-9, the action of thiol-active PPC is apparently much more specific, potent and safe. PPC presents a proof-of-concept for prophylactic contraception via manipulation of thiols in vagina for selective targeting of sperm and Trichomonas, and qualifies as a promising lead for the development of dually protective vaginal-contraceptive. PMID:23826278

  17. Crystal structures and hydrogen bonding in the proton-transfer salts of nicotine with 3,5-dinitrosalicylic acid and 5-sulfosalicylic acid

    PubMed Central

    Smith, Graham; Wermuth, Urs D.


    The structures of the 1:1 anhydrous salts of nicotine (NIC) with 3,5-dinitrosalicylic acid (DNSA) and 5-sulfosalicylic acid (5-SSA), namely (1R,2S)-1-methyl-2-(pyridin-3-yl)-1H-pyrrolidin-1-ium 2-carboxy-4,6-dinitrophenolate, C10H15N2 +C7H3N2O7 ?, (I), and (1R,2S)-1-methyl-2-(pyridin-3-yl)-1H-pyrrolidin-1-ium 3-carboxy-4-hydroxybenzenesulfonate, C10H15N2 +C7H5O6S?, (II), are reported. The asymmetric units of both (I) and (II) comprise two independent nicotinium cations (C and D) and either two DNSA or two 5-SSA anions (A and B), respectively. One of the DNSA anions shows a 25% rotational disorder in the benzene ring system. In the crystal of (I), inter-unit pyrrolidinium NH?Npyridine hydrogen bonds generate zigzag NIC cation chains which extend along a, while the DNSA anions are not involved in any formal inter-species hydrogen bonding but instead form ??-associated stacks which are parallel to the NIC cation chains along a [ring-centroid separation = 3.857?(2)?]. Weak CH?O interactions between chain substructures give an overall three-dimensional structure. In the crystal of (II), A and B anions form independent zigzag chains with C and D cations, respectively, through carboxylic acid OH?Npyridine hydrogen bonds. These chains, which extend along b, are pseudocentrosymmetrically related and give ?? interactions between the benzene rings of anions A and B and the pyridine rings of the NIC cations C and D, respectively [ring centroid separations = 3.6422?(19) and 3.7117?(19)?]. Also present are weak CH?O hydrogen-bonding interactions between the chains, giving an overall three-dimensional structure. PMID:25484766

  18. Symposium Report. Battery materials : amorphous carbons and polymer electrolytes.

    SciTech Connect

    Gerald, R. E., II; Chemical Engineering


    The motivation for research in battery materials lies in the expanding consumer demand for compact, high-energy density power sources for portable electronic devices, and environmental issues such as global warming and air pollution that have provided the impetus for mass transportation by electric vehicles. The Battery Materials Symposium, chaired by Jacqueline Johnson (ANL), focused on three topics: the structure and electrochemical properties of new and existing electrolytes, devices for fabricating and investigating thin films, and large-scale computer simulations. The symposium opened with a presentation by the author on a recently invented device for in situ investigations of batteries using nuclear magnetic resonance. Joop Schoonman (Delft University) described several methods for preparing and analyzing thin films made of solid electrolytes. These methods included chemical vapor deposition, electrostatic spray deposition and the Solufill process. Aiichiro Nakano discussed large-scale (10 million to 2 billion atoms) computer simulations of polymer and ceramic systems. An overview was given of a DOE Cooperative Research 2000 program, in the initial stages, that was set up to pursue these atomistic simulations. Doug MacFarlane (Monash University) described conductive plastic crystals based on pyrrolidinium imides. Joseph Pluth (U of Chicago) presented his recent crystallographic studies of Pb compounds found in the ubiquitous lead-acid battery. He showed the structures of tribasic lead sulfate and tetrabasic lead sulfate. Austen Angell (Arizona State Univ.) discussed the general problem of electrolyte polarization in Li-ion battery systems with cation transference numbers less than unity. Steven Greenbaum (Hunter College) provided an introduction of NMR interactions that are useful for investigations of lithium-ion battery materials. Analysis by NMR is nuclear specific, probes local environments and dynamics, and is non-destructive. He discussed {sup 7}Li NMR results of a solid electrolyte system composed of LiI dissolved in PEO. Work on oriented polymer electrolyte samples is ongoing. Yuri Andreev (U. of St. Andrews) gave a historical overview of a number of crystal structures of polymer electrolytes solved using XRD in the group of Peter Bruce. The last speaker of the symposium was Peter Papanek (U. of Pennsylvania). He spoke about various disordered carbon materials used as anodes in Li-ion batteries. He also described his inelastic neutron scattering studies of carbon materials derived from pyrolyzed epoxy novolak resins. His data supports the graphene sheet model and is also consistent with calculations of interior and edge carbon atoms in pyrene that chemically reacted with lithium.

  19. Substrate-Dependent Inhibition of Human MATE1 by Cationic Ionic Liquids

    PubMed Central

    Martnez-Guerrero, Lucy J.


    The multidrug and toxin extruders 1- and 2-K (MATE1 and MATE2-K) are expressed in the luminal membrane of renal proximal tubule cells and provide the active step in the secretion of molecules that carry a net positive charge at physiologic pH, so-called organic cations. The present study tested whether structurally distinct MATE substrates can display different quantitative profiles of inhibition when interacting with structurally distinct ligands. The tested ligands were three structurally similar cationic ionic liquids (ILs, salts in the liquid state: N-butylpyridinium, NBuPy; 1-methyl-3-butylimidazolium, Bmim; and N-butyl-N-methylpyrrolidinium, BmPy). Uptake was measured using Chinese hamster ovary cells that stably expressed MATE1 or MATE2-K. By trans-stimulation, all three ILs were transported by both MATE transporters. The three ILs also inhibited uptake of three structurally distinct MATE substrates: 1-methyl-4-phenylpyridinium (MPP), triethylmethylammonium (TEMA), and N,N,N-trimethyl-2-[methyl(7-nitrobenzo[c][1,2,5]oxadiazol-4-yl)amino]ethanaminium (NBD-MTMA). MATE1 displayed a higher affinity for the pyridinium-based NBuPy (IC50 values, 24 M) than for either the pyrrolidinium- (BmPy; 2070 M) or imidazolium-based ILs (Bmim; 1560 M). Inhibition of MPP, TEMA, and NBD-MTMA transport by NBuPy was competitive, with comparable Ki values against all substrates. Bmim also competitively blocked the three substrates but with Ki values that differed significantly (20 M against MPP and 30 M against NBD-MTMA versus 60 M against TEMA). Together, these data indicate that renal secretion of ILs by the human kidney involves MATE transporters and suggest that the mechanism of transport inhibition is ligand-dependent, supporting the hypothesis that the binding of substrates to MATE transporters involves interaction with a binding surface with multiple binding sites. PMID:23785176