Journal ArticleDOI
Molecular composition and orientation at the surface of room-temperature ionic liquids: Effect of molecular structure
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TLDR
In this paper, direct recoil spectrometry was used to investigate the composition and molecular orientation at the surfaces of a variety of room-temperature ionic liquids of the general type [Cnmim]X.Abstract:
We have used direct recoil spectrometry (DRS) to investigate the composition and molecular orientation
at the surfaces of a variety of room-temperature ionic liquids of the general type [Cnmim]X where
[Cnmim]
= 1-CnH2n+1-3-methylimidazolium cation (n
= 4 (bmim), 8 (omim), 12 (C12mim)) and X is
[PF6]−, [BF4]−, Cl− or Br−. Comparing experimental atomic F/C and H/C ratios for [Cnmim][PF6] (n
= 4, 8, 12)
or [Cnmim][BF4] (n
= 4, 8) with predicted ratios for various surface compositions suggests that the surface is populated by both anions and cations with no segregation. The data best fit the cation ring being
perpendicular rather than parallel to the surface. The data for the cations of fluorine-containing
liquids support a common orientation with the N atoms of the ring uppermost. The cations of the shorter
chain hexafluorophosphate liquids appears to stay within a rotation angular spread of about ± 30° from this
orientation but increasing the alkyl chain length to 12 carbon atoms favors a tilt of ∼45° to bring the Me
group closer to the surface. Changing to the smaller [BF4]−
anion has a similar effect. For [omim][Cl],
the data fit best for a cation orientation with either N-up or N-down and the methyl group tilted towards the
surface in a similar manner to [omim][BF4].
In the case of [omim][Br],
a number of cation orientations are compatible with the data.read more
Citations
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Journal ArticleDOI
Aggregation behavior of aqueous solutions of ionic liquids
TL;DR: The aggregation behavior in aqueous solutions of three ionic liquids based on the 1-alkyl-3-methylimidazolium cation has been investigated by means of surface tension, conductivity, and small-angle neutron scattering (SANS) measurements.
Journal ArticleDOI
Brønsted acid-base ionic liquids as proton-conducting nonaqueous electrolytes
Akihiro Noda,Md. Abu Bin Hasan Susan,Kenji Kudo,Shigenori Mitsushima,Kikuko Hayamizu,Masayoshi Watanabe +5 more
TL;DR: In this paper, a series of Bronsted acid−base ionic liquids were derived from the controlled combination of a monoprotonic acid with an organic base under solvent-free conditions.
Journal ArticleDOI
Multiscale Studies on Ionic Liquids
TL;DR: The present review aims to summarize the recent advances in the fundamental and application understanding of ILs, and introduces the structures and properties of typical ILs.
Journal ArticleDOI
Surface tensions of imidazolium based ionic liquids: anion, cation, temperature and water effect.
Mara G. Freire,Pedro J. Carvalho,Ana M. Fernandes,Isabel M. Marrucho,António J. Queimada,João A. P. Coutinho +5 more
TL;DR: The influence of water content in the surface tension was studied for several ILs as a function of the temperature as well as afunction of water mole fraction, for the most hydrophobic IL investigated, [omim][PF(6)], and one of the more hygroscopic IL, [bmim][ PF(6].
Journal ArticleDOI
Ionic Liquids in Catalysis
TL;DR: In this paper, a detailed analysis of the relevant interfaces using surface science methods is presented, including the IL/vacuum or IL/gas interface, the solubility and surface enrichment of dissolved metal complexes, the support interface and the in situ monitoring of chemical reactions in ionic liquids are presented.
References
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Journal ArticleDOI
Ionic Liquids-New "Solutions" for Transition Metal Catalysis.
Peter Wasserscheid,Wilhelm Keim +1 more
TL;DR: There are indications that switching from a normal organic solvent to an ionic liquid can lead to novel and unusual chemical reactivity, which opens up a wide field for future investigations into this new class of solvents in catalytic applications.
Journal ArticleDOI
Ionic liquids. Green solvents for the future
TL;DR: In this paper, it has been shown that Ionic liquids, being composed entirely of ions, are green solvents, and that a wide range of chemical reactions can be performed in them.
Journal ArticleDOI
Influence of chloride, water, and organic solvents on the physical properties of ionic liquids
TL;DR: The first systematic study of the effect of impurities and additives (e.g., water, chloride, and cosolvents) on the physical properties of room-temperature ionic liquids was performed in this article.
Journal ArticleDOI
Ionic Liquids for Clean Technology
TL;DR: The use of room-temperature chloroaluminate(III) ionic liquids as solvents for clean synthesis and catalytic processes, particularly those applicable to clean technology, is becoming widely recognised and accepted as mentioned in this paper.
Journal ArticleDOI
Room temperature ionic liquids of alkylimidazolium cations and fluoroanions
Rika Hagiwara,Yasuhiko Ito +1 more
TL;DR: In this article, the preparation, physical and chemical properties, and application of ionic liquids at ambient conditions are reviewed focusing on the salts of alkylimidazolium cations and fluoroanions.