How polar are room-temperature ionic liquids?

Aki, Sudhir N. V. K.; Brennecke, Joan F.; Samanta, Anunay

doi:10.1039/b008039j

Cited by 407 publications

(351 citation statements)

References 14 publications

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“…Different investigations of solvent-solute interactions in ionic liquids using solvatochromic dyes have been reported. 134,135 This is in agreement with the ionic liquid solvent effect described in the Diels-Alder reactions of cyclopentadiene with methyl acrylate. 136 The endo/ exo selectivity, which may be viewed as being dependent on the polarity of the solvent, is high (6.1:1) when using [BMIM] .…”

Section: Inorganic Synthesis In Ionic Liquidssupporting

confidence: 76%

Electrochemical routes for industrial synthesis

Sequeira¹,

Santos²

2009

J. Braz. Chem. Soc.

112

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Esta revisão examina as razões que justificam um interesse crescente da indústria química pelos processos eletrolíticos. Reveem-se as indústrias químicas, nas quais compostos orgânicos e inorgânicos são processados e descrevem-se os avanços tecnológicos mais relevantes. Inicialmente, abordam-se processos bem estabelecidos, como as indústrias cloroalcalinas de produção de alumínio, p-aminofenol, adiponitrila, etileno glicol, antraquinona, produtos perfluorados, ácido glioxílico e L-cisteína. Face à grande quantidade de informação disponível, o assunto é tratado com base científica, mas de modo bastante simplificado. Posteriormente, descrevem-se processos orgânicos e inorgânicos emergentes, nomeadamente processos eletroquímicos mediados e síntese em líquidos iónicos. Estabelecem-se paralelos entre síntese química e síntese eletroquímica. Estimula-se o interesse nos processos de eletrossíntese, particularmente em líquidos iónicos, não desmerecendo a importância das vias puramente químicas de síntese orgânica e inorgânica.This review examines the reasons for increasing interest towards electrolyses by the chemical industry, reviews the electrochemical industries as most of them now exist, and provides a status report on the key technological advances which are occurring to meet present and future needs. Classical industries like those of chloroalkali, aluminium, p-aminophenol, adiponitrile, ethylene glycol, anthraquinone, perfluorinated products, glyoxylic acid and L-cysteine are initially covered. Considering the large amount of available publications in these topics of electrochemical engineering, the covered relevant information is treated at a scientific level, although in a simplified way. Then the paper deals with emerging inorganic and organic processes, e.g. electrosynthesis in ionic liquids and mediated electrochemical processes, and finishes by assessing what the future development trend might be given the electrochemical and non electrochemical competing influences. With this approach it is hoped to stimulate the interest of chemical engineers and scientists non-specialised in electrochemical routes, and to review some cutting edge research, particularly as far as electrosynthesis in ionic liquids is concerned.

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Section: Inorganic Synthesis In Ionic Liquidssupporting

confidence: 76%

Electrochemical routes for industrial synthesis

Sequeira¹,

Santos²

2009

J. Braz. Chem. Soc.

112

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“…34,35 In fact, the polarities of imidazolium-based ILs were found to be similar to that of short chain alcohols. 36 A review regarding the polarity of ILs was presented recently by Reichardt. 37 It should, nevertheless, be kept in mind that the solvent parameters are dependent on the molecule probe employed 34 and are particularly relevant for these nanostructured fluids.…”

Section: Resultsmentioning

confidence: 99%

Evaluation of Anion Influence on the Formation and Extraction Capacity of Ionic-Liquid-Based Aqueous Biphasic Systems

et al. 2009

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Extractive fermentation using aqueous biphasic systems (ABS) is a promising separation process since it provides a nondenaturing environment for biomolecules and improves the stability of cells. Due to environmental concerns and toxicity issues related with common volatile organic solvents, ionic liquids (ILs), a new class of nonvolatile alternative solvents, are being currently investigated for extraction purposes. In this work, a wide range of imidazolium-based ILs was studied aiming at obtaining new insights regarding their ability toward the formation of ABS and their capacity to the extraction of biomolecules. On the basis of the IL cations 1-ethyl-3-methylimidazolium and 1-butyl-3-methylimidazolium, the IL anion influence on ABS formation was assessed through their combination with chloride, bromide, acetate, hydrogensulfate, methanesulfonate, methylsulfate, ethylsulfate, trifluomethanesulfonate, trifluoroacetate, and dicyanamide. Ternary phase diagrams (and respective tie-lines) formed by these hydrophilic ILs, water, and the inorganic salt K 3 PO 4 , were measured and are reported. The results indicate that the ability of an IL to induce ABS closely follows the decrease in the hydrogen bond accepting strength or the increase in the hydrogen bond acidity of the IL anion. In addition, the extraction capacity of the studied ABS was evaluated through their application to the extraction of an essential amino acid, L-tryptophan. It is shown that the partition coefficients obtained between the IL and the K 3 PO 4 -aqueous rich phases were substantially larger than those typically obtained with polymers-inorganic salts or polymers-polysaccharides aqueous systems.

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“…The most common empirical solvent polarity scale relies on the solvatochromic behavior of various dyes in different solvent systems (15)(16)(17)(18). In terms of solvent strength and selectivity, this method was also used to classify single-and mixed-solvent LC systems (20).…”

Section: Description and Propertiesmentioning

confidence: 99%

“…All results from this approach have indicated that IL solvents have polarities close to those of short-chained alcohols. Nevertheless, it is well known that two ILs with different cation-anion combinations can have significantly different effects on reaction rates, product ratios, chromatographic retention, and extraction selectivity (1,3,18). This polarity-based parameter, however, provides a "weighted average" of all solvation interactions and fails to discriminate among the various properties of ILs with different cation-anion combinations.…”

Section: Description and Propertiesmentioning

confidence: 99%

Ionic Liquids in Analytical Chemistry

Anderson¹,

Armstrong²,

Wei³

2006

Anal. Chem.

491

326

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oom-temperature ionic liquids (RTILs), also known as liquid organic, molten, or fused salts, are a class of nonmolecular ionic solvents with low melting points. The accepted definition of an RTIL is any salt that has a melting point lower than ambient temperature (1). However, "ionic liquid" (IL) is often applied to any compound that has a melting point <100°C. Most common RTILs are composed of unsymmetrically substituted nitrogen-containing cations (e.g., imidazole, pyrrolidine, pyridine) with inorganic anions (e.g., Cl -, PF 6 -, BF 4 -). ILs are also interesting because of their other useful and intriguing physicochemical properties. Wilkes et al. first reported ambient-temperature ILs based on the 1-alkyl-3-methylimidazolium cation in 1982 (2). Since then, many ILs containing a variety of cations and anions of different sizes have been synthesized to provide specific characteristics.Over the past few years, research and applications of ILs have expanded tremendously. The initial impetuses for this expansion were organic synthesis and the growth of green chemistry. In this article, we will give an overview of the structure and properties of ILs and describe their expanding use in various applications in separations and chromatography, MS, spectroscopy, and electrochemistry. Description and propertiesILs have negligible vapor pressures at room temperature, possess a wide range of viscosities, can be custom-synthesized to be miscible or immiscible, often have high stability, and are capable of un-

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How polar are room-temperature ionic liquids?

Abstract: The solvent strength and polarity of four imidazolium and pyridinium based ionic liquids, as measured using two different fluorescent probes, indicate that these liquids are more polar than acetonitrile but less polar than methanol.

Cited by 407 publications

References 14 publications

Electrochemical routes for industrial synthesis

Electrochemical routes for industrial synthesis

Evaluation of Anion Influence on the Formation and Extraction Capacity of Ionic-Liquid-Based Aqueous Biphasic Systems

Ionic Liquids in Analytical Chemistry

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