Molecular dynamics simulation studies of CO2 – [bmim][PF6] solutions: Effect of CO2 concentration

Bhargava, B. L.; Krishna, A. C.; Balasubramanian, Sundaram

doi:10.1002/aic.11596

Cited by 44 publications

(62 citation statements)

References 68 publications

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“…6 ]. 30 For instance, the position of the first peak in the anionÀanion RDF shifted from 6.5 to 8.1 Å for 0 and 70 mol % CO 2 in [bmim][PF 6 ]. 30 To investigate the effects of CO 2 concentration on [BF 4 ] À À[BF 4 ] À interactions, the RDFs and coordination numbers of BÀB were studied.…”

Section: Resultsmentioning

confidence: 99%

“…30 For instance, the position of the first peak in the anionÀanion RDF shifted from 6.5 to 8.1 Å for 0 and 70 mol % CO 2 in [bmim][PF 6 ]. 30 To investigate the effects of CO 2 concentration on [BF 4 ] À À[BF 4 ] À interactions, the RDFs and coordination numbers of BÀB were studied. As shown in Figure 6a, the absorption of CO 2 up to a mole fraction of 0.1 had no effect on the BÀB RDF, and the positions of the first peaks were both at 7.67 Å for x 2 = 0 and 0.1.…”

Section: Resultsmentioning

confidence: 99%

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Microscopic Structure, Interaction, and Properties of a Guanidinium-Based Ionic Liquid and Its Mixture with CO₂

Zhang

Liu

Yao

et al. 2011

Ind. Eng. Chem. Res.

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Recently, the guanidinium-based ionic liquid N,N,N 0 ,N 0 ,N 00 -pentamethyl-N 00 -propylguanidinium tetrafluoroborate ([ppg][BF 4 ]) was found to be able to effectively absorb CO 2 (Amitesh, M. ChemSusChem 2009, 2, 628). In this work, molecular dynamics (MD) simulations and ab initio calculations were performed to investigate the microscopic structure, interactions, and properties of pure ionic liquid [ppg] [BF 4 ] and mixtures of [ppg][BF 4 ] (1) and CO 2 (2) at x 2 = 0, 0.1, 0.3, 0.5, 0.6. CÀH 3 3 3 F hydrogen bonds were found to exist between [ppg] cations and [BF 4 ] anions by ab initio calculations. However, the H 3 3 3 F coordination numbers suggest that the H 3 3 3 F interaction decreases slightly with increasing CO 2 concentration. CO 2 molecules were found to be primarily distributed around the anions, as seen from the CO 2 Àcation and CO 2 Àanion radial distribution functions (RDFs) calculated from molecular dynamic simulations. The cationÀanion and anionÀanion structures were not perturbed even with addition of CO 2 up to 0.6 mol fraction, whereas the cationÀanion and anionÀanion interactions decreased with increasing CO 2 concentration. The volume expansion and diffusion of [ppg] [BF 4 ] increased with increasing CO 2 concentration. In addition, according to the results of RDFs and spatial distribution functions, the distribution areas of CO 2 molecules and [ppg] cations around [BF 4 ] anions were found to be nearly complementary.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Microscopic Structure, Interaction, and Properties of a Guanidinium-Based Ionic Liquid and Its Mixture with CO₂

Zhang

Liu

Yao

et al. 2011

Ind. Eng. Chem. Res.

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“…That this property is indeed primarily determined by the identity of the anions rather than by modifications of imidazolium-based cations has been confirmed in numerous studies. [6][7][8][9][10][11][12][13][14][15] Regarding anions, it was found that CO 2 solubility increased in the order of BF 4 -< TfO -< TfA -< PF 6 -< Tf 2 N -< C 7 F 15 CO 2 -< eFAP -< bFAP -. 4 In another study the following trend of increasing CO 2 solubility was found: NO 3 -< SCN -< Me- 26 Generally, ILs that contained fluorinated anions tended to exhibit higher CO 2 solubilities compared with non-fluorinated anions.…”

Section: Introductionmentioning

confidence: 99%

What Determines CO₂ Solubility in Ionic Liquids? A Molecular Simulation Study

2015

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Molecular dynamics (MD) simulations of 10 different pure and CO2-saturated ionic liquids are performed to identify the factors that determine CO2 solubility. Imidazolium-based cations with varying alkyl chain length and functionalization are paired with anions of different hydrophobicity and size. Simulations are carried out with an empirical force field based on liquid-phase charges. The partial molar volume of CO2 in ionic liquids (ILs) varies from 30 to 40 cm(3)/mol. This indicates that slight ion displacements are necessary to enable CO2 insertions. However, the absorption of CO2 does not affect the overall organization of ions in the ILs as demonstrated by almost equal cation-anion radial distribution functions of pure ILs and ILs saturated with CO2. The solubility of CO2 in ILs is not influenced by direct CO2-ion interactions. Instead, a strong correlation between the ratio of unoccupied space in pure ILs and their ability to absorb CO2 is found. This preformed unoccupied space is regularly dispersed throughout the ILs and needs to be expanded by slight ion displacements to accommodate CO2. The amount of preformed unoccupied space is a good indicator for ion cohesion in ILs. Weak electrostatic cation-anion interaction densities in ILs, i.e., weak ion cohesion, leads to larger average distances between ions and hence to more unoccupied space. Weak ion cohesion facilitates ion displacement to enable an expansion of empty space to accommodate CO2. Moreover, it is demonstrated that the strength of ion cohesion is primarily determined by the ion density, which in turn is given by the ion sizes. Ion cohesion is influenced additionally to a smaller extent by local electrostatic interactions among ion moieties between which CO2 is inserted and which do not depend on the ion density. Overall, the factors that determine the solubility of CO2 in ILs are identified consistently across a large variety of constituting ions through MD simulations.

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“…It has been known that several room temperature ionic liquids (RTILs) dissolve carbon dioxide (CO 2 ) significantly at high CO 2 pressures, and the phase behavior and the structure of the solution have been extensively studied experimentally and theoretically until now [1][2][3][4][5][6][7][8][9][10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Solvation dynamics of coumarin 153 in mixtures of carbon dioxide and room temperature ionic liquids

Kimura¹,

Kobayashi²,

Demizu³

et al. 2011

Chemical Physics Letters

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Effects of dissolved carbon dioxide (CO 2) on the solvation dynamics of coumarin 153 were studied in 1-butyl-3-methylimidazolium hexafluorophosphate, and 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide by the time resolved fluorescence spectroscopy. The solvation dynamics showed an ultrafast response less than 1 ps and a slower response extended to a half of ns under ambient condition. With increasing the CO 2 pressure, the slower component became fast, although no significant change was observed for the faster component. The CO 2 effect on the average solvation time was compared with that on the translational diffusion of the solute molecule dissolved in the mixture.

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Molecular dynamics simulation studies of CO₂ – [bmim][PF₆] solutions: Effect of CO₂ concentration

Cited by 44 publications

References 68 publications

Microscopic Structure, Interaction, and Properties of a Guanidinium-Based Ionic Liquid and Its Mixture with CO₂

Microscopic Structure, Interaction, and Properties of a Guanidinium-Based Ionic Liquid and Its Mixture with CO₂

What Determines CO₂ Solubility in Ionic Liquids? A Molecular Simulation Study

Solvation dynamics of coumarin 153 in mixtures of carbon dioxide and room temperature ionic liquids

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Molecular dynamics simulation studies of CO2 – [bmim][PF6] solutions: Effect of CO2 concentration

Cited by 44 publications

References 68 publications

Microscopic Structure, Interaction, and Properties of a Guanidinium-Based Ionic Liquid and Its Mixture with CO2

Microscopic Structure, Interaction, and Properties of a Guanidinium-Based Ionic Liquid and Its Mixture with CO2

What Determines CO2 Solubility in Ionic Liquids? A Molecular Simulation Study

Solvation dynamics of coumarin 153 in mixtures of carbon dioxide and room temperature ionic liquids

Contact Info

Product

Resources

About

Molecular dynamics simulation studies of CO₂ – [bmim][PF₆] solutions: Effect of CO₂ concentration

Microscopic Structure, Interaction, and Properties of a Guanidinium-Based Ionic Liquid and Its Mixture with CO₂

Microscopic Structure, Interaction, and Properties of a Guanidinium-Based Ionic Liquid and Its Mixture with CO₂

What Determines CO₂ Solubility in Ionic Liquids? A Molecular Simulation Study