• Title, Summary, Keyword: ionic liquids

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Biomimetic Catalysis in Ionic Liquids: Markedly Enhanced Enantioselectivity in Amino Acid-Catalyzed Directed Asymmetric Aldol Reactions

  • Yun, Suk-Jin;Lee, Jae Kwan
    • Journal of the Chosun Natural Science
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    • v.8 no.2
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    • pp.107-110
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    • 2015
  • Amino acid-catalyzed directed asymmetric aldol reactions showed enhanced enantioselectivity when conducted in ionic liquids. Optically active products were afforded in better yields (up to 23% higher) and enantiomeric excess (up to 21% higher) in ionic liquids than in conventional organic solvents.

Synthesis and Properties of Ionic Liquids:Imidazolium Tetrafluoroborates with Unsaturated Side Chains

  • Min, Gwan-Hong;Yim, Tae-eun;Lee, Hyun-Yeong;Huh, Dal-Ho;Lee, Eun-joo;Mun, Jun-young;Oh, Seung M.;Kim, Young-Gyu
    • Bulletin of the Korean Chemical Society
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    • v.27 no.6
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    • pp.847-852
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    • 2006
  • Imidazolium tetrafluoroborate ionic liquids having unsaturated aliphatic side chains were synthesized and characterized. Most of them are liquid at room temperature and all of them are stable up to $300{^{\circ}C}$. Some imidazolium tetrafluoroborates with an allylic side chain showed much wider voltage windows on the platinum electrode, better conductivities, and lower viscosities compared with the corresponding ionic liquids containing the saturated side chains.

Synthesis and characterization of physicochemical properties of hydrophilic imidazolium-based ionic liquids

  • Yousefi, Maryam;Abdouss, Majid;Beigi, Ali Akbar Miran;Naseri, Ali
    • The Korean Journal of Chemical Engineering
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    • v.34 no.9
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    • pp.2527-2535
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    • 2017
  • A series of ionic liquids based on Octyl and Decyl methylimidazolium with different anions such as chloride, glycinate, dihydrogen phosphate and trihydrogen diphosphate, were synthesized and characterized by $^1HNMR$ and elemental analysis. IL containing trihydrogen diphosphate anion, was synthesized for the first time. Physicochemical properties, including density, viscosity, surface tension, refractive index, and pH, were measured in temperature range 283.15 to 363.15 K and atmospheric pressure. The effects of temperature, alkyl chain, and anion type on physicochemical properties were investigated. The results revealed that the physicochemical properties decreased as a function of temperature. Unlike viscosity, other properties, such as density, surface tension, refractive index and pH values, decreased, while alkyl chain length increased. Understanding ILs properties and determining their unique abilities helps researchers to use them in new applications. These long alkyl chain ILs, are being used as surfactants to reduce Oil/Water interfacial tension in EOR process.

Preparation of Silver Nanoparticles in Ultrasonic Vibration-Induced Nanodroplets of Isopropyl Alcohol in Combination with Ionic Liquids

  • Shin, Ueon-Sang;Hong, Hyun-Ki;Kim, Hae-Won;Gong, Myoung-Seon
    • Bulletin of the Korean Chemical Society
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    • v.32 no.5
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    • pp.1583-1586
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    • 2011
  • Silver nanoparticles (<10 nm) were prepared in ultrasonic vibration-induced nanodroplets of isopropyl alcohol (IPA) in combination with hydrophobic room temperature ionic liquids (RTILs). The Ag-precursor used were silver (I) complex, Ag$_2$(ehac)$_2$(eha)$_2$ (ehac = 2-ethylhexylammonium carbamate; eha = 2-ethylhexylamine), in IPA, while 1-butyl-3-methylimidazolium-based ionic liquids bearing $SbF_6^-$, $PF_6^-$ and $NTf_2^-$ as counter anions were used as RTILs. During sonication for 10-90 min at room temperature, uniform silver nanoparticles with mean sizes of 2 to 8 nm were rapidly synthesized. Transmission electron micrographs also confirmed that silver nanoparticles have a spherical shape and diverse sizes depending on the reaction time (10-90 min).

Effects of Nitrile Group Substitution on the Physical Properties of Some Ionic Liquids (니트릴작용기의 치환이 몇가지 이온성 액체의 물리적 특성에 미치는 영향)

  • Ahn, Beom-Shu
    • Journal of the Korean Applied Science and Technology
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    • v.31 no.2
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    • pp.225-230
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    • 2014
  • Several nitrile-functionalized ionic liquids have been prepared and characterized. An attempt was made to systematically characterize nitrile-functionalized ionic liquids on the basis of a few kinds of cations and anions. The detailed comparison of the differences in physicical characteristics such as UV-Vis spectroscopy, thermal stability, viscosity, solubility property, and electrochemical property before and after incorporation of a nitrile group were studied. The results showed that the incorporation of a nitrile group to cations could result in remarkable changes in these properties.

Ionic Polymer-Metal Composite Actuator with Increased Air-Operating stability by Using Ionic Liquids

  • Lee, Jang-Yeol;Han, Man-Jae;Lee, Sung-Won;Park, Sun-Jin;Yoon, Bye-Ri;Jho, Jae-Young
    • Proceedings of the Polymer Society of Korea Conference
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    • pp.246-246
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    • 2006
  • Ionic polymer-metal composite (IPMC) soaked with various ionic liquids was prepared by using polystyrene sulfonic acid-grafted poly(vinylidene fluoride-co-hexafluoropropylene) as ion-exchange membrane (IEM). The prepared IPMCs were effectively deformed three times larger and actuated for 300 times longer than those of Nafion with water at the same applied conditions. The experimental results indicated than the increase in the bending capability can be caused by the increase in the improved properties of the IEMs and ionic liquids such as uptake content and ionic conductivity. And air-operating stability of the IPMCs is appreciably governed by various physical and electrochemical properties of soaked solvents in IEMs.

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Solubility of Carbon Dioxide in Strongly Basic Ionic Liquid

  • Sung, Jun-Kyung;Kim, Sung-Hyun;Cheong, Min-Serk;Baek, Il-Hyun
    • Bulletin of the Korean Chemical Society
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    • v.31 no.10
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    • pp.2797-2800
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    • 2010
  • For the purpose of developing advanced new absorbents for carbon dioxide, ionic liquids (ILs) are considered as alternative materials due to their superior properties to conventional organic solvents. Since low $CO_2$ solubility in ionic liquids is a major concern for their application as absorbents, it is essential to focus on improving $CO_2$ absorbing capability of ILs. In this paper, strongly basic ionic liquids, namely [$C_n$-mim]OPh (n = 2, 4, 6), have been synthesized and studied over a wide range of temperature and pressure changes. [$C_n$-mim]OPh can be easily synthesized from corresponding [$C_n$-mim]Cl and sodium phenoxide and has been found to be good $CO_2$ absorbents.

The Analytical Study on Synthesis and Optimization of Purification of Ionic Liquid, 1-ethyl-3-methylimidazolium Tetrafluoroborate (이온성 액체 1-ethyl-3-methylimidazolium Tetrafluoroborate의 정제 최적화 조건에 따른 특성 변화 분석 연구)

  • Yang, Kyung-Chul;Chun, Kyung-Soo
    • Journal of the Korean Ceramic Society
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    • v.50 no.2
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    • pp.103-107
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    • 2013
  • In this study, the ionic liquid 1-ethyl-3-methylimidazolium tetraflouroborate (EMI-BF4) was synthesized and purified using the liquid/liquid fractional distillation method to apply a supercapacitor. EMI-BF4 was extracted with dichloromethane from the liquid/liquid extraction method in acidic, neutral, and alkali conditions for removal of impurity, and then the electrical capacities of the purified ionic liquids were measured and compared. The electrical capacities of ionic liquids under acidic condition showed higher value than those of neutral or alkali conditions. As the ratio of ionic liquid to solvent became higher, the electrical capacity value was increased.

Morphology Effect on Electrocatalytic Activity of TiO2 Spheres Synthesized by Binary Ionic Liquids in Water Electrolysis

  • Hong, Ki-Won;Pak, Dae-Won;Yoo, Kye-Sang
    • Bulletin of the Korean Chemical Society
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    • v.33 no.6
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    • pp.1829-1833
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    • 2012
  • Titania spheres were synthesized using binary ionic liquids to examine the electrocatalytic activity in acid solution. The morphology of $TiO_2$ particles was significantly different with the composition of ionic liquids. Among the binary ionic liquids, four set of mixtures led to the formation of $TiO_2$ sphere with various sizes. The morphology and structure of $TiO_2$ particles were characterized by XRD, $N_2$ physisoption and SEM analysis. All samples possessed an anatase phase after calcinations at $500^{\circ}C$. The structural properties of the samples were varied significantly with the morphology. In cyclic voltammograms, the morphology of $TiO_2$ spheres affected the electrocatalytic activity in water electrolysis. Among the samples, [Omim][$BF_4$]+[Hmim][$BF_4$] was the most effective ionic liquid to synthesize $TiO_2$ sphere with optimum morphology showing the highest electocatalytic performance.

Solubility of carbon dioxide in ionic liquids with methylsulfate anion (Methylsulfate 음이온을 갖는 이온성 액체에 대한 이산화탄소의 용해도)

  • Jung, Jun-Young;Lee, Byung-Chul
    • Analytical Science and Technology
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    • v.24 no.6
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    • pp.467-476
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    • 2011
  • Solubility data of carbon dioxide ($CO_2$) in the imidazolium-based ionic liquids with methylsulfate anion are presented at pressures up to about 45 MPa and at temperatures between 303.15 K and 343.15 K. The ionic liquids studied in this work were 1-ethyl-3-methylimidazolium methylsulfate ([emim][$mSO_4$]), 1-butyl-3-methylimidazolium methylsulfate ([bmim][$mSO_4$]). The solubilities of $CO_2$ were determined by measuring the bubble point or cloud point pressures of the binary mixtures using a high-pressure equilibrium apparatus equipped with a variable-volume view cell. The equilibrium pressure increased very steeply at high $CO_2$ compositions. The $CO_2$ solubility in ionic liquids increased with increase of the total length of alkyl chains attached to the imidazolium cation of the ionic liquids. The phase equilibrium data for the $CO_2$ + ionic liquid systems have been correlated using the Peng-Robinson equation of state.