Influence of dissolved argon or carbon dioxide on the viscosity and surface tension of the imidazolium-based ionic liquids [OMIM][PF6] or [m(PEG2)2IM]I

Zhai, Ziwen; Koller, Thomas M.

doi:10.1016/j.molliq.2023.121491

Cited by 13 publications

(11 citation statements)

References 43 publications

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“…The corresponding expanded (k = 2) uncertainties for ρ G and η G can be found in the caption of Table 1. In line with our previous studies [22,23,32], the expanded (k = 2) uncertainty for the reported surface tension data from PD method is speci ed to be 2.0 %. This uncertaintysu ciently accounts for the uncertainty related to the used correlation for ρ L and is also considered in the evaluation of η L and its uncertainty from SLS measurements in the overdamped case.…”

Section: Resultssupporting

confidence: 68%

“…This is particularly bene cial for ILs with their commonly large viscosities, where the evaluation of the SLS signals requires information on the surface tension in order to determine the viscosity. Under such conditions, the determination of viscosity and surface tension by the combination of SLS and the PD method could be realized for ILs and IL mixtures at gas pressures between (0.02 and 10) MPa and temperatures between (303 and 393) K [22][23][24].…”

Section: Introductionmentioning

confidence: 99%

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High-temperature measurements on viscosity and surface tension of the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][NTf2]) up to 473 K

Zhai

Koller

2023

Preprint

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In the present study, the viscosity and surface tension of the commercial low-viscosity ionic liquid (IL) 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][NTf2]) were determined by a combination of surface light scattering (SLS) and the pendant-drop (PD) method between (303 and 473) K. Both methods operating at thermodynamic equilibrium were applied inside the same measurement cell at identical experimental conditions under an argon atmosphere at 0.1 MPa. For SLS measurements performed in the temperature range from (303 to 323) K, the overdamped behavior of the surface fluctuations allowed access to the viscosity with an expanded uncertainty of 2.3% by using the surface tensions determined via the PD method with an uncertainty of 2% as input quantities. Above 323 K up to 473 K, the oscillatory behavior of the probed surface fluctuations by SLS enabled a simultaneous determination of viscosity and surface tension with average expanded uncertainties of (4 and 3) %, respectively. Multiple repetition measurements by both methods have been conducted at 323 K after experiments at larger temperatures up to 473 K, and the consistency of their results could indicate a sound thermal stability of the IL sample. The mutual agreement of the surface tension results from SLS and the PD method between (353 and 473) K demonstrates that both techniques analyze the very same IL surface. For both properties, the results from this work agree well with the majority of experimental data reported in the literature typically up to 353 K. In summary, the viscosity and surface tension results presented in this study contribute to an improved data landscape for this particular IL and ILs in general at elevated temperatures.

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Section: Resultssupporting

confidence: 68%

Section: Introductionmentioning

confidence: 99%

High-temperature measurements on viscosity and surface tension of the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][NTf2]) up to 473 K

Zhai

Koller

2023

Preprint

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“…The present study aims to rectify this situation and to resolve the influence of H2 on the bulk and interfacial properties of three imidazolium-based ILs by experiments and MD simulations. This study continues our previous research on investigating experimentally the effects of gases such as CO2 and argon (Ar) on the thermophysical properties of ILs [51,52], and on modeling the bulk and interfacial properties of ILs [30,45,46,53]. In line with these investigations, the model ILs selected in the present work are the hydrophobic 1-ethyl-3methylimidazolium bis(trifluoromethanesulfonyl)imide ([C2C1Im][NTf2]) and 1-methyl-3octylimidazolium hexafluorophosphate ([C8C1Im][PF6]) as well as the hydrophilic 1,3-bis(2-(2-ethoxyethoxy)ethyl)imidazolium iodide ([(mPEG2)2Im]I), which also make it possible to cover a wide range of values of viscosities and surface tensions.…”

Section: Introductionsupporting

confidence: 72%

“…Prior to the SLS and PD measurements, the optical quality of all three IL samples was checked by irradiation of laser light, showing no noteworthy presence of larger particles. In addition, potential volatile impurities such as water and dissolved air were removed from the IL through additional evacuation, as outlined in our previous study [52]. Thereafter, the water content of the ILs was determined by Karl-Fischer coulometric titration consecutively, with the filling procedure under Ar atmosphere, after which the entire manifold was degassed before gas addition for each system.…”

Section: Materials and Sample Preparationmentioning

confidence: 99%

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Influence of Molecular Hydrogen on Bulk and Interfacial Properties of Three Imidazolium-Based Ionic Liquids by Experiments and Molecular Dynamics Simulations

Zhai,

Hantal,

Cherian

et al. 2024

Preprint

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Despite the presence of molecular hydrogen (H2) in various technical applications involving ionic liquids (ILs), its effect on the bulk and interfacial properties of ILs is poorly understood. The present study investigates the influence of dissolved H2 on the viscosity, surface tension, and phase composition of three imidazolium-based ILs by experiments and Molecular Dynamics (MD) simulations between (303 and 393) K from (0.1 to 31) MPa. The surface light scattering and pendant-drop experiments showed for all three ILs that the saturated liquid viscosity does not significantly change with increasing H2 pressure, while the surface tension decreases about 5% at 8 MPa. The MD simulations could be used to clarify microscopic origins for the behavior of the macroscopic properties. They revealed not only a compensation of compression and solvation effects due to hydrostatic pressure and dissolved H2 on the viscosity, but also a weak enrichment of H2 at the IL-gas interfaces.

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Hydrogenation with Dissolved Pt‐Complexes Homogenously Distributed in the Ionic Liquid or Enriched at the Gas/Ionic Liquid Interface

Antara,

Hemmeter,

Zhai

et al. 2024

ChemCatChem

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The use of homogeneous catalysts dissolved in ionic liquids (ILs) is an established field of research. Thin IL films containing dissolved catalyst complexes can be immobilized on solid porous supports, thereby creating a heterogenized catalyst material. Aiming at the deliberate positioning of such supported ionic liquid phase (SILP) catalyst, we carried out investigations of two very similar Pt‐complexes: depending on the ligand periphery, the first one is homogeneously dissolved in the IL while the second one strongly enriches at the gas/IL interface. To study these different locations within thick IL films of approximately 1 mm thickness, we investigated the hydrogenation of ethene in a continuous pool‐reactor setup. The two complexes dissolved in the IL [C4C1Im][PF6] showed different activity which can be attributed to their different locations. At 313 K and 0.62 MPa total pressure, the surface‐enriched complex was approximately two times more active. However, under these conditions the formation of Pt particles could be observed, with the surface‐enriched complex exhibiting a stronger tendency for particle formation compared to the one homogeneously distributed in the IL, as derived from XPS and light‐scattering measurements.

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Influence of dissolved argon or carbon dioxide on the viscosity and surface tension of the imidazolium-based ionic liquids [OMIM][PF6] or [m(PEG2)2IM]I

Cited by 13 publications

References 43 publications

High-temperature measurements on viscosity and surface tension of the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][NTf2]) up to 473 K

High-temperature measurements on viscosity and surface tension of the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][NTf2]) up to 473 K

Influence of Molecular Hydrogen on Bulk and Interfacial Properties of Three Imidazolium-Based Ionic Liquids by Experiments and Molecular Dynamics Simulations

Hydrogenation with Dissolved Pt‐Complexes Homogenously Distributed in the Ionic Liquid or Enriched at the Gas/Ionic Liquid Interface

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