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Ionic liquid

Kamal B Dhungana, Claudio Javier Margulis
The response of ionic liquids to external perturbations including elevated pressure is a topic of current interest for applications such as tribology. Ionic liquids come in many classes, including those that are amphiphilic and some that are mostly polar having either cationic or anionic tails that are functionalized. The current study compares the effect of elevated pressure on two ionic liquids with different types of cationic tail. 1-decyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide (C10mim+/NTf2-) is amphiphilic whereas isoelectronic ether-functionalized 1-(2-(2-(2-methoxyethoxy)ethoxy)ethyl)-3-methylimidazolium bis(trifluoromethylsulfonyl)amide (C7O3mim+/NTf2-) has cationic tails that are more polar and conformationally different...
June 21, 2017: Journal of Physical Chemistry. B
Joás Grossi, Jorge J Kohanoff, Niall J English, Eduardo M Bringa, Mario G Del Pópolo
Efficient charge transport has been observed in iodide-based room-temperature ionic liquids when doped with iodine. To investigate preferred pathways for the iodide (I(-))-to-triiodide (I3(-)) exchange reaction and to clarify the origin of this high ionic conductivity, we have conducted electronic structure calculations in the crystal state of 1-butyl-3-methylimidazolium iodide ([BMIM][I]). Energy barriers for the different stages of the iodine-swapping process, including the reorientation of the I(-)···I3(-) moiety, were determined from minimum energy paths as a function of a reaction coordinate...
June 21, 2017: Journal of Physical Chemistry. B
Oscar Y Fajardo, Fernando Bresme, Alexei A Kornyshev, Michael Urbakh
To a greater or lesser extent, most room temperature ionic liquids (RTILs) absorb water from humid air. Penetration of water into the lubricating nanoscale film may affect its equilibrium structure and dynamic properties and thus influence the ability of RTILs as lubricants to reduce friction between solid surfaces. Here we investigate the impact of hydration on lubrication using non-equilibrium molecular dynamics simulations. Water adsorption changes both the ionic liquid molecules orientation and the slip conditions at the solid-liquid interfaces, resulting in a reduced resistance against squeezing-out of the lubricant by an external load...
June 21, 2017: ACS Nano
Jacob Olchowka, Markus Suta, Claudia Wickleder
In this communication, nanoparticles of the fluoridosilicates A2SiF6 (A= Li, Na, K, Rb, Cs), which are extremely promising host lattices for future LEDs, are presented for the first time. The preparation method we introduces here is a very simple and energy and time saving one, moreover the usage of toxic HF or elemental fluorine is avoided. In detail, the ionic liquid [Bmim]PF6 was used both as solvent and fluoride source in an ionothermally assisted microwave synthesis. The small size of the so obtained nanoparticles is of huge relevance for their applications as thin films or coverage of surfaces for, e...
June 21, 2017: Chemistry: a European Journal
Chisato Takahashi, Yoshiki Umemura, Ayako Naka, Hiromitsu Yamamoto
In the medical biology, it is essential to understand not only biological morphology but also the interaction between biological materials and agents. To study these, electron microscopy (EM) is often utilized. However, sample preparation techniques for EM require a high level of skill and a considerable time. Here, we conducted EM using a simple technique employing a conductive liquid, BEL-1, and compared the results with another simple technique employing an ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4 ])...
June 21, 2017: Journal of Biomedical Materials Research. Part B, Applied Biomaterials
Kevin D Clark, Jeffrey A Purslow, Stephen A Pierson, Omprakash Nacham, Jared L Anderson
In this study, a series of magnetic ionic liquids (MILs) were investigated for the extraction and preconcentration of bacteria from aqueous samples. By dispersing small volumes (e.g., 15 μL) of MIL within an aqueous cell suspension, bacteria were rapidly extracted and isolated using a magnetic field. Of the seven hydrophobic MILs examined, the trihexyl(tetradecyl)phosphonium Ni(II) hexafluoroacetylacetonate ([P66614(+)][Ni(hfacac)3(-)]) MIL exhibited the greatest enrichment of viable Escherichia coli K12 when coupled with microbiological culture as the detection method...
June 20, 2017: Analytical and Bioanalytical Chemistry
Samiha Mhamdi, Intidhar Bkhairia, Rim Nasri, Tahar Mechichi, Moncef Nasri, Alya Sellami Kamoun
The aim of this study is the production of High-Added Value enzyme for Industrial Uses. An extracellular alkaline stable protease BS1 was purified from a newly bacterium, Bacillus safensis S406, isolated from the Sfax Solar Saltern. BS1 was purified by a process involving sulfate d'ammonium sulfate precipitation, sephadex G-75, Mono-Q anion-exchange chromatography and ultrafiltation. The enzyme has a molecular weight of 24kDa and appeared as a single band on native-PAGE. The optimum pH and temperature values of its proteolytic activity were pH 11...
June 17, 2017: International Journal of Biological Macromolecules
Wei Guo, Yan Zhou, Xiahan Sang, Donovan N Leonard, Jun Qu, Jonathan D Poplawsky
The development of advanced lubricant additives has been a critical component for in paving the way for increasing energy efficiency and durability for numerous industry applications. However, the formation mechanisms of additive-induced protective tribofilms are not yet fully understood due to the complex chemomechanical interactions at the contact interface and the limited spatial resolution of many characterizing techniques currently used. Here, the tribofilms on a grey cast iron surface formed by three antiwear additives are systematically studied; a phosphonium-phosphate ionic liquid (IL), a zinc dialkyldithiophosphate (ZDDP), and an IL+ZDDP combination...
June 20, 2017: ACS Applied Materials & Interfaces
Abu Taher, Kyo Chul Lee, Hye Ji Han, Dong Wook Kim
We prepared pyrene-substituted imidazolium-based ionic liquids (PILs) as organic catalysts for the SN2 fluorination using alkali metal fluoride (MF). In this system, the PIL significantly enhanced the reactivity of MF due to the phase-transfer catalytic effect of the imidazolium moiety as well as the metal cation-π (pyrene) interactions. Furthermore, this homogeneous catalyst PIL was easily separated from the reaction mixture using reduced graphene oxide by π-π stacking with the pyrene of PIL.
June 20, 2017: Organic Letters
Roman Michez, Thomas Doneux, Claudine Buess-Herman, Michel Luhmer
Potential controlled electrolyses of [BMIm][NTf2 ] ionic liquid were performed at a gold cathode under nitrogen atmosphere. The structures of the major conversion products of the BMIm(+) cation were elucidated on the basis of 1D and 2D nuclear magnetic resonance (NMR) analyses and gas chromatography (GC) analysis of the volatile compounds. Recombination of the imidazol-2-yl radicals, generated at the electrode by single electron transfer, leads to neutral diastereomeric dimers in equal proportions, with a faradaic efficiency of 80 %, while disproportionation of these radicals and/or reaction with hydrogen atoms adsorbed at the electrode generates a neutral monomer with 20 % faradaic efficiency...
June 20, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Bishwadeep Bagchi, Sushmita Sati, Vidyasagar Shilapuram
The Peng-Robinson equation of state with quadratic van der Waals (vdW) mixing rule model was chosen to perform the thermodynamic calculations in Flash3 column of Aspen Plus to predict the solubility of CO2 or any one of the hydrocarbons (HCs) among methane, ethane, propane, and butane in an ionic liquid 1-ethyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate ([emim][FAP]). Bubble point pressure, solubility, bubble point temperature, fugacity, and partial molar volume at infinite dilution were obtained from the simulations, and enthalpy of absorption, Gibbs free energy of solvation, and entropy change of absorption were estimated by thermodynamic relations...
June 19, 2017: Environmental Science and Pollution Research International
Daniel Ondo, Miguel Costas
The interaction of α-cyclodextrin (α-CD) with ten ionic surfactants (S) in water was systematically examined using isothermal titration calorimetry. The S comprised cationic and anionic head groups while the hydrocarbon alkyl chain length varied from eight to fourteen carbon atoms. The heat data were measured at five temperatures ranging from 283.15K to 318.15K and were treated simultaneously allowing the estimation of a thermodynamically consistent temperature dependence of the equilibrium constant, as well as the enthalpy and heat capacity for the sequential formation of the [α-CD·S] and the [α-CD2·S] inclusion complexes...
June 8, 2017: Journal of Colloid and Interface Science
Han Xiao, Zhong-Shuai Wu, Long Chen, Feng Zhou, Shuanghao Zheng, Wencai Ren, Hui-Ming Cheng, Xinhe Bao
Rational engineering and simplified fabrication of high-energy micro-supercapacitors (MSCs) using graphene and other 2D nanosheets are of great value for flexible and integrated electronics. In this work, we develop one-step mask-assisted simplified fabrication of high-energy MSCs based on the interdigital hybrid electrode (PG) patterns of stacking high quality phosphorene nanosheets and electrochemically exfoliated graphene in ionic liquid electrolyte (denoted as PG-MSCs). The hybrid PG films with interdigital patterns were directly manufactured by layer-by-layer deposition of phosphorene and graphene nanosheets with the assistance of a customized interdigital mask, and directly transferred onto a flexible substrate...
June 19, 2017: ACS Nano
Ayako Nitta, Takeshi Morita, Keiko Nishikawa, Yoshikata Koga
We have studied the mixing scheme of an aqueous solution of ionic liquid tetrabutylphosphonium trifluoroacetate, [P4,4,4,4]CF3COO, in the water-rich region. The mixture shows phase separation with a lower critical solution temperature. To learn how the solute [P4,4,4,4]CF3COO species interact with each other in the dilute region, the third derivative quantities of Gibbs energy in terms of enthalpy, H, and volume, V, are evaluated. In the present study using up to the third derivative quantities, we conclude that [P4,4,4,4]CF3COO turns out to be an extremely strong hydrophobe...
June 19, 2017: Physical Chemistry Chemical Physics: PCCP
Vitor L Martins, Anthony J R Rennie, Roberto M Torresi, Peter J Hall
We investigated the use of fluorine free ionic liquids (ILs) containing the tricyanomethanide anion ([C(CN)3]) as an electrolyte in electrochemical double-layer capacitors (EDLCs). Three cations were used; 1-butyl-3-methylimidazolium ([Im1,4]), N-butyl-N-methylpyrrolidinium ([Pyr1,4]) and N-butyl-N-methylpiperidinium ([Pip1,4]). Their physicochemical properties are discussed alongside with their performance as electrolytes. We found that the cyano-based ILs present higher ionic conductivity (9.4, 8.7 and 4...
June 19, 2017: Physical Chemistry Chemical Physics: PCCP
Gaoshang Wang, Shangde Sun
Estolides of ricinoleic acid (RA) have been used as lubricants and pigment dispersant in many industries. In this paper, functional acid ionic liquids (ILs) were firstly used as catalysts to prepare RA estolides by the esterification of RAs in solvent-free system. Different ILs were used as catalysts for the esterification. Effect of reaction variables (IL amount, reaction temperature and reaction time) on the esterification were also investigated and optimized using response surface methodology (RSM). Among all tested ILs, [BSO3HMIM]TS showed the best performance for the esterification...
June 13, 2017: Journal of Oleo Science
Khurrum Shehzad Quraish, Mohamad Azmi Bustam, Sooridarsan Krishnan, Noor Fathanah Aminuddin, Noraisyah Azeezah, Noraini Abd Ghani, Yoshimitsu Uemura, Jean Marc Lévêque
A promising method of Carbon dioxide (CO2) valorization is to use green microalgae photosynthesis to process biofuel. Two Phase Partitioning Bioreactors (TPPBR) offer the possibility to use non-aqueous phase liquids (NAPL) to enhance CO2 solubility; thus making CO2 available to maximize algae growth. This requires relatively less toxic hydrophobic Ionic Liquids (ILs) that comprise a new class of ionic compounds with remarkable physicochemical properties and thus qualifies them as NAPL candidates. This paper concerns the synthesis of ILs with octyl and butyl chains as well as different cations containing aromatic (imidazolium, pyridinium) and non-aromatic (piperidinum, pyrrolidinium) rings for CO2 absorption studies...
June 12, 2017: Chemosphere
João M P França, Carlos A Nieto de Castro, Agílio A H Pádua
We used molecular dynamics simulation to study the effect of suspended carbon nanomaterials, nanotubes and graphene sheets, on the thermal conductivity of ionic liquids, an issue related to understanding the properties of nanofluids. One important aspect that we developed is an atomistic model of the interactions between the organic ions and carbon nanomaterials, so we did not rely on existing force fields for small organic molecules or assume simple combining rules to describe the interactions at the liquid/material interface...
June 16, 2017: Physical Chemistry Chemical Physics: PCCP
Faiz Ullah Shah, Oleg I Gnezdilov, Andrei Filippov
This study was focused on the investigation of ion dynamics in halogen-free, hydrophobic, and hydrolytically stable phosphonium bis(salicylato)borate [P4,4,4,8][BScB] ionic liquid electrolytes for lithium-ion batteries. The structure and purity of the synthesized ionic liquid and lithium bis(salicylato)borate Li[BScB] salt were characterized using (1)H, (13)C, (31)P, and (11)B NMR spectroscopy. The Li[BScB] salt was mixed with an ionic liquid at the concentrations ranging from 2.5 mol% to 20 mol%. The physicochemical properties of the resulting electrolytes were characterized using thermal analysis (TGA and DSC), electrical impedance spectroscopy, and pulsed-field gradient (PFG) NMR and ATR-FTIR spectroscopy...
June 16, 2017: Physical Chemistry Chemical Physics: PCCP
Filipe M S Ribeiro, Carlos F R A C Lima, Inês C M Vaz, Ana S M C Rodrigues, Erlin Sapei, André Melo, Artur M S Silva, Luís M N B F Santos
This work presents a comprehensive evaluation of the phase behaviour and cohesive enthalpy of protic ionic liquids (PILs) composed of 1,5-diazabicyclo[4.3.0]non-5-ene (DBN) or 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) organic superbases with short-chain length (acetic, propionic and butyric) carboxylic acids. Glass transition temperatures, Tg, and enthalpies of vaporization, ΔHvap, were measured for six [BH][A] (1 : 1) PILs (B = DBN, DBU; A = MeCOO, EtCOO, nPrCOO), revealing more significant changes upon increasing the number of -CH2- groups in the base than in the acid...
June 16, 2017: Physical Chemistry Chemical Physics: PCCP
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