• Title, Summary, Keyword: ionic liquids

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Review : Ionic Liquids as Green Solvent (리뷰 : 녹색용매로서의 이온성액체 기술동향)

  • Lee, Junwung
    • Journal of the Korea Institute of Military Science and Technology
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    • v.16 no.5
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    • pp.690-702
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    • 2013
  • Ionic liquids(ILs) have been the most investigated chemicals among green solvents including water, glycerol, supercritical carbon dioxdie($scCO_2$). ILs are attracting organic as well as inorganic chemicals because most ionic liquids' vapor pressures are very low so that ILs are liquids phase at ambient conditions. ILs are composed of various anions and cations, thus chemists can design functionalized solvents and/or catalysts that can be used in specific synthetic reactions by means of combinations of different ions. Many scientists believe ILs being green materials because of its low vapor pressure as well as the flexibility in controlling the chemical and physical properties. In this review the author describes recent development of ILs focused on imidazolium and pyridinium ILs which are being most investigated presently. In order to apply this materials in industrial level, the toxicity matter must be resolved first. In this regard, the author describes recent research trend regarding environmental effects by ILs as well as some meaningful results as well.

Synthesis and Characterization of Quaternary Ammonium-based Ionic Liquids Containing an Alkyl Carbonate Group

  • Nguyen, Dinh Quan;Oh, Ji-Hee;Kim, Chang-Soo;Kim, Seung-Wook;Kim, Hong-Gon;Lee, Hyun-Joo;Kim, Hoon-Sik
    • Bulletin of the Korean Chemical Society
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    • v.28 no.12
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    • pp.2299-2302
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    • 2007
  • A series of quaternary ammonium-based ionic liquids (ILs) containing an alkyl carbonate group on the cation was first prepared and their physical and electrochemical properties including density, viscosity, thermal stability, electrochemical stability, and ionic conductivity were reported. These ILs exhibited wide electrochemical windows of at least 5.0 V and relatively high conductivities. In contrast to dialkyl-substituted ionic liquids, the ILs with an alkyl carbonate group on the cation showed much smaller drop in conductivities when mixed with a lithium salt, due to the interaction of lithium ions with carbonate groups. Upon interaction with a Li salt, the carbonyl stretching frequency of the carbonate group shifted to a lower frequency whereas the peak associated with C-O single bond moved to a higher frequency.

CO2 Separation Techniques Using Ionic Liquids (이온성 액체를 이용한 CO2 분리기술)

  • Cho, Min Ho;Lee, Hyunjoo;Kim, Honggon
    • Korean Chemical Engineering Research
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    • v.48 no.1
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    • pp.1-9
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    • 2010
  • Since carbon dioxide, $CO_2$, was revealed as a major greenhouse gas, techniques for its separation, capture, and storage have received increasing interest in recent years. Aqueous amines are the most widely accepted $CO_2$ absorbents, but they cause the problems such as high regeneration energy, thermal degradation, and loss of absorbents due to their volatility. Ionic liquids having high thermal stability, extremely low vapor pressure, and capability of selectively absorbing specific gases have been proposed as new $CO_2$ capturing solvents which may potentially replace aqueous amines. By reviewing the ionic liquids having capability to absorb $CO_2$ reported in previous papers, we seek to develop a comprehensive understanding on the factors that influence the $CO_2$ solubility in ionic liquids such as their structures, absorption temperature, pressure, water content, etc., and to estimate the potential of ionic liquids as $CO_2$ separating media.

Aqueous synthesis of quantum dots using functionalized ionic liquid (이온성 액체를 이용한 수계 양자 점 합성)

  • Choi, Suk-Young;Kim, Tae-Young;Suh, Kwang-S.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.254-254
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    • 2010
  • We report aqueous synthesis of cadmium telluride (CdTe) quantum dots(QDs) using imidazolium-based ionic liquids with various functional groups. The functinalized ionic liquids were designed to have thiol groups, and then phase transfer with aqueous or organic solvents can be adjusted by changing side chain lengths of the cation and the choice of anion. The quantum yield was obtained IL-functionalized CdTe QDs reached up to 40% by post-treatment method.

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Effect of Ionic Liquids with Different Cations in I-/I3- Redox Electrolyte on the Performance of Dye-sensitized Solar Cells

  • Cho, Tae-Yeon;Yoon, Soon-Gil;Sekhon, S.S.;Han, Chi-Hwan
    • Bulletin of the Korean Chemical Society
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    • v.32 no.6
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    • pp.2058-2062
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    • 2011
  • The effect of the addition of ionic liquids with four different cations (imidazolium, pyrrolidinium, piperidinium and pyridinium) on the performance of dye-sensitized $TiO_2$ solar cells based on electrolytes containing a t-butylpyridine (TBP) in 3-methoxypropionitrile (MPN) was studied. A total of 18 ionic liquids with mono-, di- and tri-alkyl derivatives were used in the present study, and among them a pyridinium cation with a mono-alkyl group showed better cell efficiency than the others. The best photoelectric conversion efficiency, 7.213%, was obtained using 1-hexylpyridinium iodide with an open-circuit photovoltage ($V_{oc}$) = 0.731 V, a short-circuit photocurrent density ($J_{sc}$) = 16.175 $mA/cm^2$, and a fill factor (ff) = 0.610 under AM1.5 and 100 $mW/cm^2$ illumination.

Optimization of Extraction of Astaxanthin from Portunus trituberculatus by Ionic Liquids (이온성 액체를 사용한 꽃게 껍질에서 아스타크산틴 추출 조건의 최적화)

  • Lee, Yu Jin;Lee, Yu Ri;Tang, Baokun;Row, Kyung Ho
    • KSBB Journal
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    • v.28 no.4
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    • pp.238-243
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    • 2013
  • Astaxanthin is one of the carotenoid with strong antioxidant. The conditions of extraction of astaxanthin from Portunus trituberculatus were optimized in this work. Six factors of conditions such as, extraction method, extraction solvent, ratio of solvent to raw material, temperature, and time, were investigated. For the increase of the extraction yield, ionic liquids were used as additives in the extraction solvent. The optimum extraction conditions were found: heat reflux extraction, Dichloromethane/methanol (25:75, v/v) as solvent, 1:30 of the ratio of solvent raw material, $80^{\circ}C$, 90 min, and ionic liquid as additive. As a result, 45.81 ${\mu}g/g$ of astaxanthin was extracted from waste.

Application of X-ray photoelectron spectroscopy (XPS) in ionic liquids

  • Park, Ju-Yeon;Seo, Cho-Hyeon;Seo, Seong-Yong;Gang, Yong-Cheol
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.117-117
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    • 2015
  • Availability of X-ray photoelectron spectroscopy (XPS) for the identification of ionic liquids (ILs) was tested. Commercially available ionic liquids (1-butyl-3-methyl imidazolium tetrafluoroborate ([BMIM] $BF_4$), (1-butyl-3-methyl imidazolium trifluoromethanesulfonate ([BMIM] OTf), (1-butyl-3-methyl imidazolium hexafluorophosphate ([BMIM] $PF_6$), 1-hexyl-3-imidazolium hexafluorophosphate ([HMIM] $PF_6$), and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM] $Tf_2N$) were qualitatively and semi-quantitatively analyzed with XPS. In order to confirm whether the results of XPS were correct, conventional method such as a nuclear magnetic resonance (NMR) was performed. After the XPS results were convinced by NMR, we synthesized ILs (1-(4-sulfonic acid) butyl-3-butylimidazolium trifluoromethanesulfonate ([SBBIM] OTf), 1-(4-sulfonic acid) propyl-3-methylimidazolium trifluoromethanesulfonate ([SPMIM] OTf), and 1-(4-sulfonic acid) propyl-3-butylimidazolium trifluoromethanesulfonate ([SPBIM] OTf) and analyzed it with XPS and NMR as well. It was successful the usage of XPS to analyze ILs without any purification processes.

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Tribological performance of some organic fluorine-containing compounds as lubricants

  • Liu, Weimin;Ye, Chengfeng;Xue, Qunji
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • pp.349-350
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    • 2002
  • The friction and wear behaviors of fluorine-containing compounds such as perfluoropolyethers (PFPE), phosphazenes (X-1P), ionic liquids as lubricants for steel/seel, steel/ceramic, ceramic/ceramic were investigated using a SRV tester and a one-way reciprocating friction tester both in ball-on-disc configuration. It was found that the three fluorine-containing lubricants could reduce friction coefficient and wear volume effectively. The effectiveness of the three lubricants in reducing wear volume could be ranked as ionic liquids>X-1P>PFPE. Tests also showed that aryloxyphosphazene with polar substituent as a lubricant of steel/steel pair gave low wear, while aryloxyphosphazene with nonpolar group on the phenyl pendant led to high wear. The morphology and the tribo-chemical reaction of the worn surfaces were analyzed with a scanning electron microscope (SEM) and X-ray photoelectron spectroscope (XPS). XPS analyses illustrated the formation of iron fluoride in steel/steel system with the lubrication of both phosphazenes and ionic liquids.

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Prediction of Reaction Performance of Isobutane Alkylation Using Ionic Liquid (이온성액체를 이용한 이소부탄 알킬레이션 반응성능에 대한 예측)

  • Kim, Soo Jung;Yoo, Kye Sang
    • Applied Chemistry for Engineering
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    • v.26 no.3
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    • pp.347-350
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    • 2015
  • In this study, ionic liquids have been employed as a green catalyst in the alkylation of isobutane with 2-butene. One of acid ionic liquids, 1-octyl-3-methylimidazolium-bromide-aluminum chloride, was used in the reaction. Effects of the liquid hourly space velocity (LHSV), reaction temperature and composition of ionic liquids on the reaction performance were investigated in order to optimize reaction conditions. Under identical reaction conditions, the optimum reaction temperature was $80^{\circ}C$ and the ionic liquid with the anion composition of 0.56 showed an excellent reaction activity. Moreover, a correlation model was developed with a statistical approach to predict the product yields.