Physical data for a process to separate krypton from air by selective absorption in an ionic liquid

Afzal, Waheed; Liu, Xiang Yang; Prausnitz, John M.

doi:10.1016/j.fluid.2015.06.037

Cited by 14 publications

(12 citation statements)

References 28 publications

(43 reference statements)

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“…To remove particle-like impurities and to reduce the slight yellowish coloration, the [HMIM][NTf 2 ] was filtered twice with a stack of polytetrafluoroethylene (PTFE) syringe filters with a pore size of (0.45 and 0.2) μm at ambient conditions. To remove possible water impurities leading to systematic errors in D 11 , , [HMIM][NTf 2 ] was dried on a vacuum line under rigorous stirring at about T = 312 K and p = 0.4 Pa for 8 h. The water content of the investigated samples was determined before and after the experimental investigations by Karl Fischer coulometric titration (Metrohm, 756 KF Coulometer) with an expanded relative uncertainty ( k = 2) of less than 20%. A summary of the purity and water content of [HMIM][NTf 2 ] and the purity of CO 2 as certified by the supplier is listed in Table .…”

Section: Methodsmentioning

confidence: 99%

Fick Diffusion Coefficient in Binary Mixtures of [HMIM][NTf₂] and Carbon Dioxide by Dynamic Light Scattering and Molecular Dynamics Simulations

et al. 2021

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Dynamic light scattering (DLS) experiments and equilibrium molecular dynamics (EMD) simulations were performed in the saturated liquid phase of the binary mixture of 1-hexyl-3-methylimidazolium bis(trifluormethylsulfonyl)imide ([HMIM][NTf2]) and carbon dioxide (CO2) to access the Fick diffusion coefficient (D 11). The investigations were performed within or close to saturation conditions at temperatures between (298.15 and 348.15) K and CO2 mole fractions (x CO2) up to 0.81. The DLS experiments were combined with polarization-difference Raman spectroscopy (PDRS) to simultaneously access the composition of the liquid phase. For the first time in an electrolyte-based system, D 11 was directly calculated from EMD simulations by accessing the Maxwell–Stefan (MS) diffusion coefficient and the thermodynamic factor. Agreement within combined uncertainties was found between D 11 from DLS and EMD simulations for CO2 mole fractions up to 0.5. In general, an increasing D 11 with increasing x CO2 could be observed, with a local maximum present at a CO2 mole fraction of about 0.75. The local maximum could be explained by an increasing MS diffusion coefficient with increasing x CO2 over the entire studied composition range and a decreasing thermodynamic factor at x CO2 above 0.7. Finally, PDRS and EMD simulations were combined to investigate the influence of the fluid structure on the diffusive process.

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Section: Methodsmentioning

confidence: 99%

Fick Diffusion Coefficient in Binary Mixtures of [HMIM][NTf₂] and Carbon Dioxide by Dynamic Light Scattering and Molecular Dynamics Simulations

et al. 2021

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“…To reduce the amount of particle-like impurities and to limit discoloration, the ILs were filtered after the synthesis twice at ambient conditions with a stack of (0.45 and 0.2) μm pore size polytetrafluoroethylene syringe filters. To avoid falsified D 11 values rising from the presence of water, , the ILs were dried on a vacuum line under rigorous stirring at a temperature T = 312 K and pressure p = 0.4 Pa for at least 8 h and were then stored under argon atmosphere. The water content by mass w water of the investigated samples was determined before and after the DLS experiments by Karl Fischer coulometric titration (Metrohm, 756 KF coulometer) with an expanded relative uncertainty ( k = 2) of about 20%.…”

Section: Methodsmentioning

confidence: 99%

Diffusivities in Binary Mixtures of [AMIM][NTf₂] Ionic Liquids with the Dissolved Gases H₂, He, N₂, CO, CO₂, or Kr Close to Infinite Dilution

et al. 2020

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Ionic liquids (ILs) are interesting working fluids in many areas of chemical and energy engineering such as gas separation, catalysis, or energy storage. For the optimum design of related processes and apparatuses, the diffusion coefficient of gases dissolved in ILs is necessary, yet is often only known for a few selected gases. In this work, the thermal and mutual diffusivities in binary mixtures consisting of the gases hydrogen, helium, nitrogen, carbon monoxide, carbon dioxide, or krypton dissolved in the homologous series of the ILswere investigated by dynamic light scattering (DLS) and equilibrium molecular dynamics (EMD) simulations for temperatures between (298 and 423) K at conditions close to infinite dilution of the dissolved gas. Here, the Fick diffusion coefficient determined by DLS can be compared with the self-diffusion coefficient of the dissolved gases predicted by EMD simulations. For the latter, selected force fields (FFs) for the ILs available in literature were tested, for which the most suitable FF was modified by scaling the partial charges of all atoms with an IL-specific factor using experimental data for density, viscosity, and the self-diffusion coefficient of the pure ILs. On the basis of the modified FF, agreement of the calculated gas self-diffusion coefficients and the experimental Fick diffusion coefficients with an average absolute relative deviation of 12% was found. The Fick diffusion coefficient increases with decreasing molecular weight of the dissolved gas, with the exception of hydrogen and helium, which show an inverse behavior. In contrast to the trends observed for binary mixtures of the above gases dissolved in n-alkanes or 1alcohols of varying alkyl chain length, the diffusion coefficients of the mixtures with the different ILs investigated in this study were found to be not significantly affected by the solvent viscosity.

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“…Complete removal of volatiles was confirmed by 1 H NMR. Water byproduct was then removed by further drying at 323 K under reduced pressure for Representative 1 H, 13 C, and 19 F NMR spectra are included in the Supporting Information. 2.2.…”

Section: Experimental Methodsmentioning

confidence: 99%

“…Tabular data of the densities and viscosities of the IL investigated; tables of the O 2 uptakes values at 293, 313, and 333 K; synthesis details; and representative 1 H, 13 C, and 19 F NMR spectra for the synthesized materials (PDF)…”

Section: * S Supporting Informationmentioning

confidence: 99%

“…The authors showed that adding fluorination to the anion increased the O 2 solubility. For example, the Henry’s law constant of O 2 in [hmim][eFAP] is 60.2 ± 6.3 MPa at 298 K and is 35.8 ± 2.7 MPa in [hmim][pFAP] at 298 K. Moreover, Afzal et al , measured the O 2 solubility in 1-butyl-3-H-imidazolium acetate, [bHim][Ac], and trihexyltetradecylphosphonium bis(2,4,4-trimethylpentyl)phosphinate, [P 66614 ][TMPP], up to a partial pressure of 4 MPa using an isochoric-saturation method. [P 66614 ][TMPP] shows high O 2 solubility, with a Henry’s law constant of 1.46 MPa at 313 K. In 2016, Zhou et al published experimental O 2 solubility data for up to 5.185 MPa partial pressure in two ether-functionalized imidazolium ionic liquids: 1-methoxyethyl-3-methylimidazolium hexafluorophosphate ([EOMmim][PF 6 ]) and 1-methoxyethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([EOMmim][TFSI]).…”

Section: Introductionmentioning

confidence: 99%

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Solubility and Diffusivity of Oxygen in Ionic Liquids

2019

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The solubility of O 2 was measured gravimetrically in 16 ionic liquids (ILs) containing piperidinium, pyrrolidinium, ammonium, tetrahydrothiophenium, methyltriazabicyclodecene, or guanidinium cations paired with bis(trifluoromethanesulfonyl)imide, bis(perfluoroethylsulfonyl)imide, or perfluoropropanoyl(trifluoromethylsulfonyl)imide anions. The temperature dependence of the solubility was determined for eight of the ILs. Henry' law constants were determined from the solubility data as well as standard enthalpies and entropies of absorption for systems with temperature-dependent data. Knowledge of these thermodynamic properties is essential in guiding the structural design of ionic liquids for different applications involving O 2 . The O 2 solubility did not follow any obvious trend with regard to IL structure or molar volume; instead, the dipole−quadrupole interactions are the primary driving forces for O 2 dissolution in ionic liquids, as demonstrated by negative standard enthalpies of absorption for all of the ILs. In addition, diffusion coefficients of O 2 in the ILs as a function of temperature (293, 313, and 333 K) and applied O 2 pressure (1, 3, and 5 MPa) were obtained by fitting the time-dependent absorption data to a widely used mass diffusion model. The diffusion coefficients of O 2 in ionic liquids at 293 K and 1 MPa roughly correlate inversely with the pure IL viscosity, likely due to the relatively low and similar O 2 solubilities under these conditions. As expected, O 2 diffusivities increase with increasing temperature. However, they also increase with increasing pressure, likely due to decreasing solution viscosity with increasing gas solubility.

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Physical data for a process to separate krypton from air by selective absorption in an ionic liquid

Cited by 14 publications

References 28 publications

Fick Diffusion Coefficient in Binary Mixtures of [HMIM][NTf₂] and Carbon Dioxide by Dynamic Light Scattering and Molecular Dynamics Simulations

Fick Diffusion Coefficient in Binary Mixtures of [HMIM][NTf₂] and Carbon Dioxide by Dynamic Light Scattering and Molecular Dynamics Simulations

Diffusivities in Binary Mixtures of [AMIM][NTf₂] Ionic Liquids with the Dissolved Gases H₂, He, N₂, CO, CO₂, or Kr Close to Infinite Dilution

Solubility and Diffusivity of Oxygen in Ionic Liquids

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Physical data for a process to separate krypton from air by selective absorption in an ionic liquid

Cited by 14 publications

References 28 publications

Fick Diffusion Coefficient in Binary Mixtures of [HMIM][NTf2] and Carbon Dioxide by Dynamic Light Scattering and Molecular Dynamics Simulations

Fick Diffusion Coefficient in Binary Mixtures of [HMIM][NTf2] and Carbon Dioxide by Dynamic Light Scattering and Molecular Dynamics Simulations

Diffusivities in Binary Mixtures of [AMIM][NTf2] Ionic Liquids with the Dissolved Gases H2, He, N2, CO, CO2, or Kr Close to Infinite Dilution

Solubility and Diffusivity of Oxygen in Ionic Liquids

Contact Info

Product

Resources

About

Fick Diffusion Coefficient in Binary Mixtures of [HMIM][NTf₂] and Carbon Dioxide by Dynamic Light Scattering and Molecular Dynamics Simulations

Fick Diffusion Coefficient in Binary Mixtures of [HMIM][NTf₂] and Carbon Dioxide by Dynamic Light Scattering and Molecular Dynamics Simulations

Diffusivities in Binary Mixtures of [AMIM][NTf₂] Ionic Liquids with the Dissolved Gases H₂, He, N₂, CO, CO₂, or Kr Close to Infinite Dilution