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Room Temperature Ionic Liquids (room + temperature_ionic_liquid)

Distribution by Scientific Domains

Chemistry	86%
Polymers and Materials Science	13%

Selected Abstracts

Fabrication, Characterization, and Application of ,Sandwich-Type' Electrode Based on Single-Walled Carbon Nanotubes and Room Temperature Ionic Liquid

ELECTROANALYSIS, Issue 17 2008
Xuzhi Zhang
Abstract The much-enhanced electrochemical responses of potassium ferricyanide and methylene blue (MB) were firstly explored at the glassy carbon electrode modified with single-walled carbon nanotubes (SWNT/GCE), indicating the distinct electrochemical activity of SWNTs towards electroactive molecules. A hydrophobic room temperature ionic liquid (RTIL), 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6), was used as electrode modification material, which presented wide electrochemical windows, proton permeation and selective extraction ability. In consideration with the advantages of SWNTs and RTIL in detecting target molecules (TMs), a novel strategy of ,sandwich,type' electrode was established with TMs confined by RTIL between the SWNT/GCE and the RTIL membrane. The strategy was used for electrochemical detection of ascorbic acid (AA) and dopamine (DA), and detection limits of 400 and 80 fmol could be obtained, respectively. The selective detection of DA in the presence of high amount of AA could also be realized. This protocol presented many attractive advantages towards voltammetric detection of TMs, such as low sample demand, low cost, high sensitivity, and good stability. [source]

Paste Electrode Based on Short Single-Walled Carbon Nanotubes and Room Temperature Ionic Liquid: Preparation, Characterization and Application in DNA Detection

ELECTROANALYSIS, Issue 12 2008
Xuzhi Zhang
Abstract A paste electrode (SWNT&RTIL PE) has been prepared using carboxylic group-functionalized short single-walled carbon nanotubes (SWNTs) mixed with 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6, one kind of room temperature ionic liquid, RTIL). Its electrochemical behavior was investigated by cyclic voltammetry and electrochemical impedance spectroscopy in comparison with the paste electrode using mineral oil as a binder. Results highlighted the advantages of the paste electrode: not only higher conductivity, but also lower potential separation (,Ep), higher peak current (ip) and better reversibility towards dopamine (DA), methylene blue (MB) and K3[Fe(CN)6]. The SWNT&RTIL PE could be used to detect the number of guanine bases and adenine bases contents in per mol oligonucleotides according to the current response in the range of 0.05,2.0,nM. Based on the current response of guanine bases, oligonucleotides could be detected sensitively in the B,R buffer solution with a detection limit of 9.9,pM. The heterogeneous electron transfer rate constant (ks) of guanine bases contents in the oligonucleotides was investigated and its value was 0.90,s,1. In essence the SWNT&RTIL PE showed high sensitivity, reliability, stability and reproducibility for the detection of DNA. [source]

A Room Temperature Ionic Liquid (RTIL)-Mediated, Non-Hydrolytic Sol,Gel Methodology to Prepare Molecularly Imprinted, Silica-Based Hybrid Monoliths for Chiral Separation,

ADVANCED MATERIALS, Issue 24 2006
H.-F. Wang
Silica-based hybrid molecularly imprinted polymer (MIP) monoliths with good chiral recognition ability are synthesized (see figure) using a novel method, a room temperature ionic liquid (RTIL)-mediated, non-hydrolytic sol,gel technique. The approach avoids the cracking and shrinking of the bed during drying, which is commonly associated with conventional sol,gel processing, overcomes the shortcomings associated with conventional organic-polymer-based MIP matrices, and offers improved selectivity. [source]

Efficient and Convenient Procedure for Protection of Hydroxyl Groups to the THP, THF and TMS Ethers and Oxidation of these Ethers to Their Aldehydes or Ketones in [BPy]FeCl4 as a Low Cost Room Temperature Ionic Liquid.

CHEMINFORM, Issue 33 2006
Ahmad R. Khosropour
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source]

Room Temperature Ionic Liquid Promoted Improved and Rapid Synthesis of 2,4,5-Triaryl Imidazoles from Aryl Aldehydes and 1,2-Diketones or ,-Hydroxyketone.

CHEMINFORM, Issue 31 2005
Shapi A. Siddiqui
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

Epoxidation of Olefins Catalyzed by Manganese(III) Porphyrin in a Room Temperature Ionic Liquid.

CHEMINFORM, Issue 22 2003
Zhen Li
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

Synthesis of Oxygen-Containing Spirobipyrrolidinium Salts for High Conductivity Room Temperature Ionic Liquids

HELVETICA CHIMICA ACTA, Issue 8 2009
Seiichiro Higashiya
Abstract Synthesis of ionic liquids (IL) based on oxygen-containing spirobipyrrolidinium salts with BF4, BF3C2F5, and NTf2 as counterions was undertaken. Their physical and electrochemical properties were evaluated for suitability for Room Temperature Ionic Liquids (RTIL) application. Reduction in melting point occurred upon exchange of C(2) by an O-atom of spirobipyrrolidinium, without sacrificing the electrochemical stability; while introduction of alkyl groups between the N- and O-atoms led to incorporation of asymmetry, and hence reduced the melting points, and viscosity. [source]

Peptide Synthesis in Room Temperature Ionic Liquids.

CHEMINFORM, Issue 22 2004
Helene Vallette
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

A Mild and Efficient Synthesis of 5-Oxo-5,6,7,8-tetrahydro-4H -benzo-[b]-pyran Derivatives in Room Temperature Ionic Liquids

CHINESE JOURNAL OF CHEMISTRY, Issue 8 2005
Jiang Zhao-Qin
Abstract A one-pot synthesis of a series of 5-oxo-5,6,7,8-tetrahydro-4H -benzo-[b]-pyran derivatives via three-component coupling reactions of aldehydes, dimedone and malononitrile in room temperature ionic liquids (RTILs) without any catalyst has been reported. In the meantime, the reuse of ionic liquids and the effect of different ionic liquids as solvent on the reaction have also been investigated. [source]

Fabrication, Characterization, and Application of ,Sandwich-Type' Electrode Based on Single-Walled Carbon Nanotubes and Room Temperature Ionic Liquid

Paste Electrode Based on Short Single-Walled Carbon Nanotubes and Room Temperature Ionic Liquid: Preparation, Characterization and Application in DNA Detection

Dramatic Effects of Ionic Liquid on Platinum Electrode Surface and Electron-Transfer Rates of meso -Tetraphenylporphyrins

ELECTROANALYSIS, Issue 12 2006
Afsaneh Safavi
Abstract The effect of addition of a room temperature ionic liquid, 1-butyl-3-methyl imidazolium hexafluorophosphate [bmim][PF6], on the electrochemical behavior of different free-base para-substituted meso -tetraphenylporphyrins in dichloromethane solution has been studied using cyclic voltammetric technique. It has been found that the ionic liquid has the ability to regenerate platinum electrode surface and improves the reversibility of electrode processes. This has been true for the case of all the porphyrins studied. [source]

Ultrasound-Assisted Synthesis of CuO Nanorods in a Neat Room-Temperature Ionic Liquid

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 19 2009
Tarek Alammar
Abstract CuO nanorods were prepared via ultrasound-assisted synthesis in the room temperature ionic liquid (RTIL) 1-butyl-3-methylimidazoliumbis(trifluoromethylsulfonyl)imide [C4mim][Tf2N] as a reaction medium. The structure and morphology of CuO nanorods were characterized with X-ray powder diffraction (XRD), transmission electron microscopy (TEM), energy-dispersive X-ray analysis (EDX), X-ray photoelectron spectroscopy (XPS), vibrational and UV/Vis absorption spectroscopy. The synthesized CuO nanocrystals are of rod like shape with lengths from 30 to 100 nm and diameters of about 10 nm. Quantum size effects were observed as the bandgap of the CuO nanorods was determined to 2.41 eV from UV/Vis absorption measurements, which is significantly larger than the bulk value. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source]

A Room Temperature Ionic Liquid (RTIL)-Mediated, Non-Hydrolytic Sol,Gel Methodology to Prepare Molecularly Imprinted, Silica-Based Hybrid Monoliths for Chiral Separation,

Comparison of the Effects of an Ionic Liquid and Other Salts on the Properties of Electrospun Fibers, 2 , Poly(vinyl alcohol)

MACROMOLECULAR MATERIALS & ENGINEERING, Issue 1 2009
Ganesh Kumar Arumugam
Abstract Understanding the effect of conductivity in electrospinning solutions is crucial in order to improve or control the electrospinning process. In this paper the effect of adding small amounts (0.039,0.259 mol,·,kg,1) of three different conductive additives to aqueous solutions of polyvinyl alcohol has been investigated. The salts were HMICl (a room temperature ionic liquid), TEBAC (a quaternary ammonium salt) and KCl. Addition of these salts caused a steady increase in the solution conductivity but the fiber diameter was typically greater than that of PVA alone, and exhibited an oscillatory trend. The oscillatory trend on the fiber diameter is attributed to fiber backbuilding and fusion that occurs prior to deposition on the collector. [source]

Effect of Lewis acids on the Diels,Alder reaction in ionic liquids with different activation modes

JOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 4 2008
Ana Vidi
Abstract The Diels,Alder reaction has been examined in room temperature ionic liquids with high molar concentrations of Lewis acids under various conditions. A molar ratio of 10% catalyst gave a large increase in the selectivity and the yield of the reaction. The effect of catalysts on reaction rates was also examined under 100,MPa of pressure which leads to modest improvements in reaction rates. Ultrasound and microwave dielectric heating were also shown to improve the rate and, to a minor extent, selectivity of the examined reactions. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Ionic liquids: solvent properties and organic reactivity

JOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 4 2005
Cinzia Chiappe
Abstract Ionic liquids are a fascinating class of novel solvents, which are attracting attention as possible ,green' alternative to volatile molecular organic solvents to be applied in catalytic and organic reactions and electrochemical and separation processes. Over 200 room temperature ionic liquids are known but for most of them physico-chemical data are incomplete or lacking. Furthermore, despite the incredible number of potential ionic liquids (evaluated as ,>,1014), generally only a few imidazolium-based salts are used in synthesis. Moreover, most of the data reported to date were focused on the effect that these new solvents have on chemical reaction products; only a few reports evidence the effect on reaction mechanisms or rate or equilibrium constants. In this review, the physico-chemical properties of the most used ionic liquids, that are relevant to synthesis, are discussed and a decided emphasis is placed on those properties that most clearly illuminate the ability of ionic liquids to affect the mechanistic aspects of some organic reactions. Copyright © 2004 John Wiley & Sons, Ltd. [source]

Temperature Dependence of the Dielectric Properties and Dynamics of Ionic Liquids

CHEMPHYSCHEM, Issue 4 2009
Johannes Hunger
Abstract No solo dancers: The temperature dependence of dielectric spectra suggests that the lower-frequency relaxation dominating the dynamics of imidazolium-based room temperature ionic liquids cannot be solely due to independent rotational diffusion of the cations (see picture), but must also include cooperative motions of the surrounding particles. Dielectric spectra were measured for eight, mostly imidazolium-based, room temperature ionic liquids (RTILs) over a wide range of frequencies (0.2,,/GHz,89) and temperatures (5,,/°C, 65). Detailed analysis of the spectra shows that the dominant low frequency process centred at ca. 0.06 to 10 GHz (depending on the salt and the temperature) is better described using a symmetrically broadened Cole,Cole model rather than the asymmetric Cole,Davidson models used previously. Evaluation of the temperature dependence of the static permittivities, effective dipole moments, volumes of rotation, activation energies, and relaxation times derived from the dielectric data indicates that the low frequency process cannot be solely due to rotational diffusion of the dipolar imidazolium cations, as has been thought, but must also include other contributions, probably from cooperative motions. Analysis of the Debye process observed at higher frequencies for these RTILs is not undertaken because it overlaps with even faster processes that lie outside the range of the present instrumentation. [source]

Olefin Epoxidation with a New Class of Ansa -Molybdenum Catalysts in Ionic Liquids

CHEMSUSCHEM CHEMISTRY AND SUSTAINABILITY, ENERGY & MATERIALS, Issue 5 2010
Daniel Betz
Is that a finalansa? Different room temperature ionic liquids (RTILs) are examined as solvents in the biphasic epoxidation of selected olefins with the ansa compounds 1 and 2 as catalyst precursors. Turnover frequencies of up to 44,000,h,1 are reached and the catalyst can easily be separated and recycled. [source]

A Mild and Efficient Synthesis of 5-Oxo-5,6,7,8-tetrahydro-4H -benzo-[b]-pyran Derivatives in Room Temperature Ionic Liquids

Selective Extraction of Bioproducts by Ionic Liquids

CHINESE JOURNAL OF CHEMISTRY, Issue 6 2005
Wang Jian-Ji
Abstract Imidazolium based room temperature ionic liquids have been used to extract selectively L -tryptophan from fermentation broth. anion was found to enhance dramatically the partitioning of L -tryptophan into ionic liquid phase from aqueous solutions. [source]

Electrochemical reduction of benzoylformic acid in ionic liquid

CHINESE JOURNAL OF CHEMISTRY, Issue 9 2003
Jia-Xing Lu
Abstract Ionic liquids possess a number of unique properties that make them ideal electrolytes. Electrochemical reduction of benzoylformic acid in room temperature ionic liquids as reaction media could be conducted with excellent performances without any additional supporting electrolyte. Electrolysis at glassy carbon electrode results in the formation of mandelic acid in 91% yield. And the electrochemical behavior of benzoylformic acid was investigated with the technique of cyclic voltammetry. [source]