Thermodynamic characterization of deep eutectic solvents at high pressures

Crespo, Emanuel A.; Costa, João Miguel Lopes; Palma, André M.; Soares, Belinda; Martín, M. Carmen; Segovia, José J.; Coutinho, João A. P.

doi:10.1016/j.fluid.2019.112249

Cited by 39 publications

(59 citation statements)

References 103 publications

(180 reference statements)

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“…3b. This viscosity profile is similar to what is usually observed in the literature for DES mixtures[7,27,28], with a more or less marked exponential decrease of the viscosity with the increase of the temperature. In a DES, the viscosity is mainly related to the formation of hydrogen bonds and van der Waals interactions.…”

supporting

confidence: 88%

New hydrophobic deep eutectic solvent for electrochemical applications

Chaabene

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Turmine

et al. 2020

Journal of Molecular Liquids

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Deep eutectic solvents (DESs) are known as cheap and biodegradable solvents which are easier to synthesize than ionic liquids (ILs). In this work, a new hydrophobic DES based on menthol is described. It consisted in a mixture of menthol and acetic acid in which ethanolamine has been added in order to increase the conductivity up to few mS.cm-1. The physicochemical properties as a function of temperature, in the range of 293 to 333 K, of this menthol-based DES have been compared to the ethaline, which is one of the most widely used DES. Cyclic voltammetry has been used to study the electrochemical behavior of an electroactive mediator, the hydroxymethylferrocene (FcMeOH), which is a reversible electrochemical system and its diffusion coefficient, determined in both DESs, is of the same order of magnitude than the one reported for the 1-ethyl-3-methylimidazolium bis(trifluoro-methanesulfonyl)imide (EMIMTFSI), which is the most widely used IL for electrochemical applications. This new class of DES thus provide an eco-friendly alternative for electrochemical applications.

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supporting

confidence: 88%

New hydrophobic deep eutectic solvent for electrochemical applications

Chaabene

Ngo

Turmine

et al. 2020

Journal of Molecular Liquids

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“…Data presented in Figure 3 shows an increase of viscosity at pressures up to 50 bar; these observations are in accordance with previous measurements of viscosity in DES. 66 In our study, viscosity reaches a maximum at 50 bar after which a clear decrease could be observed; this trend is observable at both temperatures studied. where ln refers to viscosity deviations from ideal behavior, f(v) is a characteristic function of the free volume, and G R is the residual energy of mixing which is closely related to the excess energy of mixing and the molar volumes of the compounds in the mixture (R represents the ideal gas constant and T, the temperature).…”

Section: Rationalization Of Co2 Effect In Choline Tosylalaninate/glycerol Systemsupporting

confidence: 70%

Palladium Nanoparticles in Glycerol/Ionic Liquid/Carbon Dioxide Medium as Hydrogenation Catalysts

Garg

Masdeu‐Bultó

Farfán

et al. 2020

ACS Appl. Nano Mater.

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In this work, the influence of carbon dioxide on the synthesis of palladium nanoparticles (PdNPs) in glycerol/ionic liquid mixtures and their further applications in catalytic hydrogenations, was studied. In the glycerol/choline tosylalaninate/CO2 medium, small and very well-dispersed metal nanoparticles were obtained (1.3 ± 0.3 nm), exhibiting a relative narrow size distribution. Palladium nanoparticles prepared in the presence of supercritical carbon dioxide (scCO2) showed higher catalytic reactivity in comparison with those prepared in its absence. In addition, we observed a beneficial effect of CO2 in the studied hydrogenations. With the aim of rationalizing this trend, measurements of viscosity of the solvent media were carried out by using fluorescent molecular rotors, allowing the determination of diffusion coefficients for the organic substrates and molecular hydrogen. This study evidenced that CO2 causes a decrease of the viscosity of the medium and an increase of the diffusion constants of reagents including H2; consequently, PdNPs in the glycerol/choline tosylalaninate/CO2 solvent showed an enhanced catalytic activity. From both process engineering and environmental points of view, it is important to highlight the efficiency of the extraction of organic products from the catalytic glycerol/ionic liquid solution by scCO2.

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“…Several studies have been carried out regarding the thermophysical properties of several ILs and DES [ 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 ], and both have been proved to be good dispersant media for CNTs dispersion [ 21 , 34 , 35 , 36 , 37 , 38 , 39 ].…”

Section: Introductionmentioning

confidence: 99%

Characterization of Carbon Nanomaterials Dispersions: Can Metal Decoration of MWCNTs Improve Their Physicochemical Properties?

et al. 2021

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A suitable dispersion of carbon materials (e.g., carbon nanotubes (CNTs)) in an appropriate dispersant media, is a prerequisite for many technological applications (e.g., additive purposes, functionalization, mechanical reinforced materials for electrolytes and electrodes for energy storage applications, etc.). Deep eutectic solvents (DES) have been considered as a promising “green” alternative, providing a versatile replacement to volatile organic solvents due to their unique physical-chemical properties, being recognized as low-volatility fluids with great dispersant ability. The present work aims to contribute to appraise the effect of the presence of MWCNTs and Ag-functionalized MWCNTs on the physicochemical properties (viscosity, density, conductivity, surface tension and refractive index) of glyceline (choline chloride and glycerol, 1:2), a Type III DES. To benefit from possible synergetic effects, AgMWCNTs were prepared through pulse reverse electrodeposition of Ag nanoparticles into MWCNTs. Pristine MWCNTs were used as reference material and water as reference dispersant media for comparison purposes. The effect of temperature (20 to 60 °C) and concentration on the physicochemical properties of the carbon dispersions (0.2–1.0 mg cm−3) were assessed. In all assessed physicochemical properties, AgMWCNTs outperformed pristine MWCNTs dispersions. A paradoxical effect was found in the viscosity trend in glyceline media, in which a marked decrease in the viscosity was found for the MWCNTs and AgMWCNTs materials at lower temperatures. All physicochemical parameters were statistically analyzed using a two-way analysis of variance (ANOVA), at a 5% level of significance.

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Thermodynamic characterization of deep eutectic solvents at high pressures

Cited by 39 publications

References 103 publications

New hydrophobic deep eutectic solvent for electrochemical applications

New hydrophobic deep eutectic solvent for electrochemical applications

Palladium Nanoparticles in Glycerol/Ionic Liquid/Carbon Dioxide Medium as Hydrogenation Catalysts

Characterization of Carbon Nanomaterials Dispersions: Can Metal Decoration of MWCNTs Improve Their Physicochemical Properties?

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