Electrical Conductivity and Solubility of KF in <i>N</i>,<i>N</i>-Dimethylformamide up to 125 °C

Macfie, Gavin; Compton, and Richard. G.; Corti, Horacio R.

doi:10.1021/je0100241

Cited by 17 publications

(7 citation statements)

References 18 publications

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“…The curve shows a rapid increase in the dilute regime, then reaches a maximum at about 0.15 M and progressively decreases when c further increases. The presence of a maxi mum is a typical behavior that suggests the formation of ion pairs and triple ions (K 2 F + and KF 2 − ) [20]. In most cases the maximum is preceded by a minimum, corresponding to the onset of triple ions formation [12].…”

Section: Electric Conductivity Measurementsmentioning

confidence: 99%

The curious effect of potassium fluoride on glycerol carbonate. How salts can influence the structuredness of organic solvents

Sarri

Tatini

Ambrosi

et al. 2018

Journal of Molecular Liquids

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Glycerol carbonate (4-hydroxymethyl-1,3-dioxolan-2-one, shortly GC) is a dense, viscous, water soluble solvent. The high dielectric constant and dipole moment make it a suitable non-aqueous green solvent for several salts in different applications. GC dissolves significant amounts of inorganic salts such as KF. The saturation of GC with KF leads to the formation of a viscous liquid at room temperature. In this paper, we report on conductivity, rheology, differential scanning calorimetry and infrared spectroscopy experiments that indicate the formation of a glassy liquid where GC molecules and KF ion pairs are intercalated in a firm and ordered bidimensional structure, stabilized by hydrogen bonding and strong ion-dipole interactions.

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Section: Electric Conductivity Measurementsmentioning

confidence: 99%

The curious effect of potassium fluoride on glycerol carbonate. How salts can influence the structuredness of organic solvents

Sarri

Tatini

Ambrosi

et al. 2018

Journal of Molecular Liquids

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“…11,12 Even in highly polar aprotic solvents such as DMF, the solubility and degree of dissociation are small. 13 To increase the reactivity of K + F − and to lessen the twisted transition state (TS-2 in Figure 1a), the counterion K + was replaced with a highly bulky cation (e.g., Bu 4 N + ), 14 but this substitution increased the cost and led to side reactions, such as eliminations, because of the higher basicity. 15 Chelators with a high affinity to K + such as cryptands (e.g., K 222 ), crown ethers (e.g., 18-crown-6, BTC5A 16 ), and bis-terminal hydroxy polyethers 17 have been utilized (Figure 1a).…”

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confidence: 99%

“…However, the strong hydrogen bond between water and fluoride significantly reduces the nucleophilicity of fluoride. KF is not very soluble in most organic solvents and exists mainly as an ion pair rather than dissociated free ions in a solution. , Even in highly polar aprotic solvents such as DMF, the solubility and degree of dissociation are small …”

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confidence: 99%

Unbalanced-Ion-Pair-Catalyzed Nucleophilic Fluorination Using Potassium Fluoride

Hammond

et al. 2021

Org. Lett.

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An unbalanced ion pair promoter (e.g., tetrabutylammonium sulfate), consisting of a bulky and charge-delocalized cation and a small and charge-localized anion, greatly accelerates nucleophilic fluorinations using easy handling KF. We also successfully converted an inexpensive and commercially available ion-exchange resin to the polymer-supported ion pair promoter (A26–SO4 2–), which could be reused after filtration. Moreover, A26–SO4 2– can be used in continuous flow conditions. In our conditions, water is well-tolerated.

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“…Note that the electrical conductivity of all suspensions was higher than reported conductivities of the pure solvents (DMF »2.5 mS/cm [Macfie et al 2001], »6.5 mS/cm [Theron et al 2004]; NMP < 0.02 mS/cm [Chen et al 2012]; and ethanol »0. 1 mS/cm [Modesto-L opez and Biswas 2010]).…”

Section: Zeta Potential and Electrical Conductivity Of Graphene Suspementioning

confidence: 63%

Films of Graphene Nanomaterials Formed by Ultrasonic Spraying of Their Stable Suspensions

Modesto-López

Miettinen

Riikonen

et al. 2014

Aerosol Science and Technology

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Graphene, a two-dimensional carbon allotrope, exhibits excellent optoelectronic properties. The assembly of graphene into films provides a platform to deepen the study of its interaction with varying surfaces, to engineer devices, and to develop functional materials. A general approach to produce graphene films consists of preparing a dispersion and laying it on a substrate of choice, followed by solvent evaporation. Here, we report the preparation of stable suspensions of new types of graphene nanomaterials namely, graphene nanoflowers (GNFs) and multi-layer graphene (MLG) flakes, in ethanol, N,Ndimethylformamide (DMF), and N-methyl-2-pyrrolidone (NMP). Sprayable suspensions of both GNFs and MLG were prepared in DMF/ethanol, which showed high stability, without addition of any surfactant. The stable suspensions were used to deposit micrometer-thick MLG/GNF films on glass substrates. Calculations of initial droplet size and of timescale of droplet evaporation are performed and possible thermophoretic effects on droplet deposition discussed as well. Coating glass substrates with a methacrylic acid-methyl methacrylate (MA) copolymer prior to the deposition significantly improved the adhesion of the nanomaterials to the substrate. With the MA coating, a substrate coverage of nearly 100% was achieved at 14-min spraying time for 0.05 wt% GNF and 0.1 wt% MLG suspensions. Raman spectra of the GNF and MLG films reveal that the films were made of MLG in which the individual graphene layers rotated from each other as in turbostratic graphene. This work provides a general approach to prepare graphene nanomaterial suspensions and to create films for a variety of applications. The spraying process applied in the current work is highly scalable and allows control of film characteristics through process parameters.

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Electrical Conductivity and Solubility of KF in N,N-Dimethylformamide up to 125 °C

Cited by 17 publications

References 18 publications

The curious effect of potassium fluoride on glycerol carbonate. How salts can influence the structuredness of organic solvents

The curious effect of potassium fluoride on glycerol carbonate. How salts can influence the structuredness of organic solvents

Unbalanced-Ion-Pair-Catalyzed Nucleophilic Fluorination Using Potassium Fluoride

Films of Graphene Nanomaterials Formed by Ultrasonic Spraying of Their Stable Suspensions

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