Ionic liquids. Green solvents for the future

Earle, Martyn J.; Seddon, Kenneth R.

doi:10.1351/pac200072071391

Cited by 2,597 publications

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References 31 publications

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“…An identical one-electron mechanism to PCl 3 , equations (5)- (7), was proposed, 19 and was also successfully simulated by digital simulation. For POCl 3 , the reaction was found to be slightly less shifted towards the product (POCl 4 -in this case). As is clearly observed in Figure 6, peaks P 5 , P 6 and P 7 are the oxidations of POCl 3 parent molecules.…”

Section: Reduction and Oxidation Of Phosphorus Oxychloride Poclmentioning

confidence: 63%

“…The asymmetry of the forward and reverse peaks in RTILs has been found 37 to be due to the large discrepancy in the diffusion coefficients of O 2 and O 2 ; they vary by a factor of thirty in some RTILs, compared to just three in acetonitrile. From potential step chronoamperometry, the diffusion coefficient of O 2 at 298 K was found to be 1.18 (± 0.10) × 10 -10 and 0.64 (± 0.05) × 10 -10 m 2 s -1 , and the solubility was found to be 11.5 (± 0.5) and 9.5 (± 0.4) mmol L -1 in [C 4 6 ] respectively. Although the mechanism for O 2 reduction is found to be the same in RTILs and conventional solvents, the different behaviour in the two RTILs suggests that the kinetics of diffusion for oxygen and superoxide is sensitive to the choice of the RTIL solvent.…”

Section: Reduction Of Oxygenmentioning

confidence: 99%

“…2 Their low volatility has allowed a recent study 3 of solute solubility in RTILs using X-ray Photoelectron Spectroscopy (a technique usually only applied to solids) and also means they may have environmental benefits as "greener" alternatives to volatile organic solvents. 4 Their high intrinsic conductivity means that no supporting electrolyte is required in electrochemical experiments, minimizing experimental set-up and waste. Due to the high stability of the cations and anions, the electrochemical window can be very wide (ca.…”

Section: Introductionmentioning

confidence: 99%

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The electrochemistry of simple inorganic molecules in room temperature ionic liquids

Silvester¹,

Rogers²,

Barrosse-Antle³

et al. 2008

J. Braz. Chem. Soc.

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A eletroquímica de compostos inorgânicos simples em líquidos iônicos a temperatura ambiente (RTIL) é revisada e alguns trabalhos novos nesta área são apresentados. Este artigo focaliza a comparação entre o comportamento eletroquímico em RTILs e em solventes apróticos convencionais. Alguns compostos (iodetos, O 2 , NO 2 , SO 2 , NH 3 ) apresentam reações e mecanismos similares em RTILs e em solventes apróticos (como é observado para compostos orgânicos). Entretanto, outras espécies (nitratos, PCl 3 , POCl 3 ) mostram comportamento excepcionalmente diferente em relação aos solventes tradicionais. Isto torna os RTILs um meio promissor para o estudo de compostos inorgânicos, e destaca a necessidade de maiores investigações nesta área.The electrochemistry of simple inorganic compounds in room temperature ionic liquids (RTILs) is reviewed and some new work in this area is presented. This paper focuses on the comparison between electrochemical behaviour in RTILs and in conventional aprotic solvents. Some compounds (iodides, O 2 , NO 2 , SO 2 , NH 3 ) display similar reactions and mechanisms in RTILs as in aprotic solvents (as is observed for organic compounds). However other species (nitrates, PCl 3 , POCl 3 ) show remarkably different behaviour to traditional solvents. This makes RTILs very promising media for the study of inorganic compounds, and highlights the need for more investigations in this exciting area.

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Section: Reduction and Oxidation Of Phosphorus Oxychloride Poclmentioning

confidence: 63%

Section: Reduction Of Oxygenmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The electrochemistry of simple inorganic molecules in room temperature ionic liquids

Silvester¹,

Rogers²,

Barrosse-Antle³

et al. 2008

J. Braz. Chem. Soc.

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“…[1][2][3] Work has focussed on liquids formed from dialkylimidazolium halides which are readily prepared from 1-methylimidazole and a slight excess of the desired haloalkane. 4 Addition of a suitable molar ratio of aluminium chloride to these salts gives rise to ionic liquids containing complex metal anions which have been used in a number of applications such as electroplating, electrochemical devices and catalysts for organic synthesis.…”

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confidence: 99%

Preparation of novel, moisture-stable, Lewis-acidic ionic liquids containing quaternary ammonium salts with functional side chains

et al. 2001

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Ionic liquids, or room temperature molten salts, have attracted increasing interest over recent years, particularly in the area of green chemistry, due to their advantageous properties including negligible vapour pressure and wide liquid range. 1-3 Work has focussed on liquids formed from dialkylimidazolium halides which are readily prepared from 1-methylimidazole and a slight excess of the desired haloalkane. 4 Addition of a suitable molar ratio of aluminium chloride to these salts gives rise to ionic liquids containing complex metal anions which have been used in a number of applications such as electroplating, electrochemical devices and catalysts for organic synthesis. 1,[4][5][6] The main disadvantage of imidazolium-based liquids is their relatively high cost for bulk applications, whilst chloroaluminate ionic liquids have the additional problem of their low tolerance to moisture, necessitating the use of glove box and Schlenk techniques to prepare and investigate their properties. The former problem may be overcome by using cheaper ammonium salts whereas the latter may be solved by replacing aluminium with less reactive metals.Recently, Freeman and coworkers have characterised ionic liquids formed from FeCl 2 or FeCl 3 and 1-butyl-3-methylimidazolium chloride. 7 However, other examples of ionic liquids made from metal chlorides other than aluminium are less well characterised and are mainly cited in conference proceedings 8 or in the patent literature. 9,10 Here we report the synthesis and characterisation of new moisture-stable, Lewis-acidic ionic liquids made from metal chlorides and quaternary ammonium salts that are commercially available or simple to synthesise. These offer the potential to tailor the physical properties e.g. melting point, viscosity and conductivity, and to tune the Lewis acidity by choosing a different metal or indeed combinations of metals.To investigate the parameters necessary for a salt to be liquid at or near room temperature we have heated a range of ammonium salts with zinc chloride in a 1+2 molar ratio and the results are shown in Since choline chloride, [Me 3 NC 2 H 4 OH]Cl, gave the lowest freezing point we have characterised this system in more detail. Heating mixtures of choline chloride and zinc chloride in molar ratios between 1+1 and 1+3 gave rise to clear colourless liquids, with the freezing points varying between ca. 65 °C (1+1), 25 °C (1+2) and 45 °C (1+3). Unlike analogous aluminium systems, 4,11,12 ratios with a molar excess of choline chloride, i.e. basic melts, do not form ambient temperature liquids in these systems. This would imply that complex zinc anions, in which the charge can be delocalised, are necessary in the formation of these ionic liquids. Further characterisation of the 1:2 liquid is described below.A 1 H NMR spectrum of the neat ionic liquid was recorded and shows resonances at d 2.97, 3.34 and 3.94 assigned to the methyl groups, N-CH 2 protons, and the CH 2 OH protons, respectively, of the choline cation. All signals were broad and poorly reso...

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“…[7][8][9][10] ILs are comprised of cations and anions with low symmetry, disfavoring their packing into stable crystals.…”

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confidence: 99%

Extraction of DNA staining dyes from DNA using hydrophobic ionic liquids

et al. 2013

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The partition of oligonucleotides and DNA staining dyes into a few hydrophobic ionic liquids has been studied, where the oligonucleotides remain in the aqueous phase and all the DNA staining dyes are extracted in the ionic liquid phase, allowing the separation of these two. 10DNA staining dyes are commonly used in molecular biology and analytical chemistry for detecting not only nucleic acids, but also metal ions, small molecules and proteins (e.g. with DNA aptamers). [1][2][3][4][5][6] Most DNA staining dyes are conjugated cationic molecules and they bind to DNA via electrostatic, - 15 stacking and intercalation interactions to produce strong fluorescence. The DNA/dye complex is very stable and can often survive gel electrophoresis. Therefore, one of the analytical challenges is to remove the dye after staining so that precious DNA samples might still be used for other 20 applications. So far, no attempts have been reported to achieve this goal.Ionic liquids (ILs) are molten salts at around room temperature. [7][8][9][10] ILs are comprised of cations and anions with low symmetry, disfavoring their packing into stable crystals. 25With very low vapor pressure, ILs are considered to be green solvents that may replace some of the conventional organic solvents. Recently, ILs have been shown to dissolve many biopolymers. 11-14 Some protein enzymes are more stable and active in ILs. 15 ILs can also provide long-term stability to 30 DNA. 16 Various studies have been carried out to understand the interaction between ILs and DNA. [17][18][19][20][21][22] There are two types of ILs; one type is hydrophilic and miscible with water while the other type is hydrophobic and forms a separate phase in water. We recently reported that 35 some hydrophilic ILs can either act as salt to increase the melting temperature (Tm) of DNA or as solvent to reduce its Tm. 22 Hydrophobic ILs, on the other hand, might be used for analyte enrichment and extraction. [23][24][25] Hydrophobic ILs have also been used for DNA separation, 26 translocation, 27 mass 40 spectrometry, 28 and DNA gel fiber formation. 29 We reason that hydrophobic ILs might interact with DNA staining dyes via electrostatic, hydrophobic and van der Waals interactions, which may be stronger than its interaction with DNA. In this work, we demonstrate extraction of DNA staining dye from 45 DNA using hydrophobic ILs.A total of four ILs were studied in this work ( Figure 1A As an initial test, we mixed a 24-mer single-stranded (ss) DNA with SYBR Green I dye (SG) in buffer (50 mM NaCl, 20 mM HEPES, pH 7.6). A strong green fluorescence was observed under UV excitation ( Figure 1B). We then added an equal volume of [Bmim][PF6]. After a 55 thorough mixing and then centrifugation to facilitate phase separation, the fluorescence disappeared. This suggests that the DNA and SG either are separated into different phases or are both extracted into the IL phase, where the fluorescence was quenched. 60To confirm the location of DNA, we repeated the experiment with a Cy3-labeled DNA ( Figu...

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Ionic liquids. Green solvents for the future

Cited by 2,597 publications

References 31 publications

The electrochemistry of simple inorganic molecules in room temperature ionic liquids

The electrochemistry of simple inorganic molecules in room temperature ionic liquids

Preparation of novel, moisture-stable, Lewis-acidic ionic liquids containing quaternary ammonium salts with functional side chains

Extraction of DNA staining dyes from DNA using hydrophobic ionic liquids

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