The dipolarity/polarisability of 1-alkyl-3-methylimidazolium ionic liquids as function of anion structure and the alkyl chain length

Lungwitz, Ralf; Strehmel, Veronika; Spange, Stefan

doi:10.1039/b9nj00751b

Cited by 141 publications

(123 citation statements)

References 49 publications

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“…Strong hydrogen-bonding basicity alkyl methylimidazolium-based ILs can be designed using various anions: Ac, (MeO)MePO 2 , (MeO)HPO 2 , HCO 2 , (MeO) 2 PO 2 , Cl, H 2 PO 2 . Furthermore, the dipolarity/polarizability studied [97] as a function of cation-anion interaction strength indicates an increase with stronger ion pairing effect i.e., the resulting cation effect on π* is different with weakly coordinating anion compared to the strongly coordinating anion (e.g., chloride). It is expected that 1-alkyl-3-methylimidazolium cations show larger values of π* [98], even when compared with different cations sharing the same anion, such that imidazolium > pyridinium > pyrrolidinium [99].…”

Section: Hydrogen Bond Basicity Of Cellulose Dissolving Ilsmentioning

confidence: 99%

Ionic Liquid as Reaction Media for the Production of Cellulose-Derived Polymers from Cellulosic Biomass

et al. 2017

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Abstract:The most frequent polymer on nature is cellulose that is present together with lignin and hemicellulose in vegetal biomass. Cellulose can be, in the future, sustainable raw matter for chemicals, fuels, and materials. Nevertheless, only 0.3% of cellulose is processed nowadays due to the difficulty in dissolving it, and only a small proportion is used for the production of synthetic cellulosic fibers especially esters and other cellulose derivatives, normally in extremely polluting processes. The efficient and clean dissolution of cellulose is a major objective in cellulose research and development. Ionic liquids (ILs) are considered "green" solvents due to their low vapor pressure, that prevents them evaporating into the atmosphere. In addition, these molten salts present advantages in process intensification, leading to more than 70 patents in lignocellulosic biomass in ILs being published since 2005, most of them related to the production of cellulose derived polymers, e.g., acetates, benzoylates, sulfates, fuorates, phthalates, succinates, tritylates, or silylates. In this work, the use of ILs for production of cellulose derived polymers is thoroughly studied. To do so, in the first place, a brief summary of the state of the art in cellulose derivatives production is presented, as well as the main features of ILs in cellulose processing applications. Later, the main results in the production of cellulose derivatives using ILs are presented, followed by an analysis of the industrial viability of the process, considering aspects such as environmental concerns and ILs' recyclability.

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Section: Hydrogen Bond Basicity Of Cellulose Dissolving Ilsmentioning

confidence: 99%

Ionic Liquid as Reaction Media for the Production of Cellulose-Derived Polymers from Cellulosic Biomass

et al. 2017

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“…These contributions can be experimentally separated by using three or more dyes, which reflect these properties to a different extent. Lungwitz et al 68 and Hallett and Welton 70 have recently discussed some key facets of this approach with regard to ILs.…”

Section: Solvent Polaritymentioning

confidence: 99%

“…Spectroscopic probes for assessing local interactions are often founded in UV/VIS absorption or fluorescence spectra of solvatochromic dyes. [67][68][69][70] Although the results depend on the dye used, 68 solvatochromic methods commonly assign to aprotic ILs polarities similar to those of acetonitrile or methanol, corresponding to dielectric constants of e D 25-40. These values are markedly higher than the measured e values.…”

Section: Solvent Polaritymentioning

confidence: 99%

How ionic liquids can help to stabilize native proteins

Weingärtner

Cabrele

Herrmann

2012

Phys. Chem. Chem. Phys.

260

233

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The native state of a globular protein is essential for its biocatalytic function, but is marginally stable against unfolding. While unfolding equilibria are often reversible, folding intermediates and misfolds can promote irreversible protein aggregation into amorphous precipitates or highly ordered amyloid states. Addition of ionic liquids-low-melting organic salts-offers intriguing prospects for stabilizing native proteins and their enzymatic function against these deactivating reaction channels. The huge number of cations and anions that form ionic liquids allows fine-tuning of their solvent properties, which offers robust and efficient strategies for solvent optimization. Going beyond case-by-case studies, this article aims at discussing principles for a rational design of ionic liquid-based formulations in protein chemistry and biocatalysis.

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“…be performed by employing solvatochromic absorption probes. [11][12][13][14] Care has to be taken in the interpretation of such steady-state spectroscopic studies when using solvatochromic probes, such as Reichardt's dye (E T N polarity scale), or the Kamlet-Taft parameter for dipolarity/polarizability, p*, where the influence of other solvent effects such as hydrogen-bonding may render unambiguous conclusions difficult.…”

Section: Introductionmentioning

confidence: 99%

Dielectric relaxation and ultrafast transient absorption spectroscopy of [C6mim]+[Tf2N]−/acetonitrile mixtures

Lohse

Bartels

Stoppa

et al. 2012

Phys. Chem. Chem. Phys.

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Mixtures of the ionic liquid (IL) [C 6 influence of discrete ion pairs. Employing static dielectric constants from the DRS experiments, one finds that the lifetime of the probe in the IL mixtures is shorter than that in pure organic solvents with the same polarity parameter. This suggests an increased stabilization of the S 1 /ICT state in IL-containing mixtures, most likely due to IL-specific Coulombic interactions between the cation and the negative end of the probe's dipole. An ultrafast solvation component is observed which is ca. 0.5 ps in pure acetonitrile, and approaches the value for the pure IL (2.0 ps) already around x(IL) = 0.3. This is interpreted in terms of an efficient perturbation of the cooperative solvation response of acetonitrile by the presence of small amounts of IL and possibly also the viscosity increase when adding IL. This view is also supported by the increase of the average longitudinal relaxation time of acetonitrile upon addition of small IL amounts extracted from the DRS experiments.

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The dipolarity/polarisability of 1-alkyl-3-methylimidazolium ionic liquids as function of anion structure and the alkyl chain length

Cited by 141 publications

References 49 publications

Ionic Liquid as Reaction Media for the Production of Cellulose-Derived Polymers from Cellulosic Biomass

Ionic Liquid as Reaction Media for the Production of Cellulose-Derived Polymers from Cellulosic Biomass

How ionic liquids can help to stabilize native proteins

Dielectric relaxation and ultrafast transient absorption spectroscopy of [C6mim]+[Tf2N]−/acetonitrile mixtures

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