Molecular dynamics study of hydrated alkali and halide ions in liquid nitrobenzene

Benjamin, Ilan

doi:10.1016/j.jelechem.2010.09.009

Cited by 14 publications

(12 citation statements)

References 34 publications

(49 reference statements)

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“…64 Similarly, the strongly hydrated Li + ions maintain an average hydration number of ∼4.3 at 1 M [LiNO 3 ], using a distance cutoff r min of 3.0Å in good agreement with the bulk aqueous phase. 65,66 Fitting the equilibrium constants K 1 and K 2 to the simulation data, using the equations S7 and S9 in the Supplementary Information, yields values of 0.12 and 0.04, respectively, which are well-within the range of experimental observation from spectroscopic measurements and are closest to the values of K 1 = 0.15 ± 0.04 at 6.25 M ionic strength in a solution of NaNO 3…”

Section: Interfacial Slab and Identification Of Truly Interfacial Molecules Analysissupporting

confidence: 52%

Uranyl Speciation in the Presence of Specific Ion Gradients at the Electrolyte/Organic Interface

Kumar

Servis

Clark

2021

Solvent Extraction and Ion Exchange

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Uranyl (UO2+ 2 ) speciation at the liquid/liquid interface is an essential aspect of the mech?anism that underlies its extraction as part of spent nuclear fuel reprocessing schemes and environmental remediation of contaminated legacy waste sites. Of particular importance is a detailed perspective of how changing ion concentrations at the liquid interface alter the distribu?tion of hydrated uranyl ion and its interactions with complexing electrolyte counterions relative to the bulk aqueous solution. In this work, classical molecular dynamics simulations have ex?amined uranyl in bulk LiNO3(aq) and in the presence of a hexane interface. UO2+ 2 is observed to have both direct coordination with NO− 3 and outer-sphere interactions via solvent-separated ion-pairing (SSIP), whereas the interaction of Li+ with NO− 3 (if it occurs) is predominantly as a contact ion-pair (CIP). The variability of uranyl interactions with nitrate is hypothesized to prevent dehydration of uranyl at the interface, and as such the cation concentration is un?perturbed in the interfacial region. However, Li+ loses waters of solvation when it is present in the interfacial region, an unfavorable process that causes a Li+ depletion region. Although significant perturbations to ion-ion interactions, solvation, and solvation dynamics are observed in the interfacial region, importantly, this does not change the association constants of uranyl with nitrate. Thus, the experimental association constants, in combination with knowledge of the interfacial ion concentrations, can be used to predict the distribution of interfacial uranyl nitrate complexes. The enhanced concentration of uranyl dinitrate at the interface, caused by excess adsorbed NO− 3 , is highly relevant to extractant ligand design principles as such nitrate complexes are the reactants in ligand complexation and extraction events. File list (2) download file view on ChemRxiv Uranyl_complexation_and_solvation_in_nitrate_f.pdf (1.59 MiB) download file view on ChemRxiv Uranyl_complexation_and_solvation_in_nitrate_SI.pdf (4.00 MiB)

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Section: Interfacial Slab and Identification Of Truly Interfacial Molecules Analysissupporting

confidence: 52%

Uranyl Speciation in the Presence of Specific Ion Gradients at the Electrolyte/Organic Interface

Kumar

Servis

Clark

2021

Solvent Extraction and Ion Exchange

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“…The dynamics of water molecules exchanging between the first and second shell have been examined extensively for ions of different charges and sizes in bulk water, 40−42 at liquid interfaces 4 and in hydrophobic media. 43,44 The residence time of water molecules in the hydronium ion's first hydration shell is determined by following the residence time correlation function: 40,41,45−47…”

Section: Resultsmentioning

confidence: 99%

“…The increase in the residence time as the ion crosses the interface has been observed for other ion transfer cases across liquid/liquid interfaces 4 and around hydrated ions in hydrophobic media. 43,44 Another measure of ion dynamics that can be influenced by the liquid/liquid interface roughness is the ion's diffusion constant. Although the diffusion constant can be easily determined in bulk liquids from conductivity measurements, complications arise at interfaces because of the fact that the ion motion is not isotropic: translations parallel and perpendicular to the interface are different and depend on the ion location along the interface normal.…”

Section: Resultsmentioning

confidence: 99%

“…However, these water molecules are not permanently attached to the ion and they could be exchanged with nearby water molecules. The dynamics of water molecules exchanging between the first and second shell have been examined extensively for ions of different charges and sizes in bulk water, − at liquid interfaces and in hydrophobic media. , The residence time of water molecules in the hydronium ion’s first hydration shell is determined by following the residence time correlation function: ,,− where for each water molecule “ i ”, h i ( t ) = 1 as long as this water molecule is inside the first hydration shell (or leaves for a time period shorter than some lag time, which we take to be 2 ps). N is the total number of water molecules, n ( t ) is the number of water molecules in the first hydration shell at time t , and the ensemble average is taken over all the time origins t ′.…”

Section: Resultsmentioning

confidence: 99%

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Molecular Dynamics Studies on the Effect of Surface Roughness and Surface Tension on the Thermodynamics and Dynamics of Hydronium Ion Transfer Across the Liquid/Liquid Interface

Benjamin

2020

J. Phys. Chem. B

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Molecular dynamics simulations are used to examine the effect of surface roughness and surface tension on the transfer of the classical hydronium ion (H3O+) across the water/1,2-dichloroethane interface. Free energy of transfer, hydration structure, and dynamics as a function of the ion location along the interface normal are calculated with six different values of a control parameter whose variation modifies the surface tension without impacting the bulk properties of the two solvents. Transfer of the classical hydronium ion across the water/1,2-dichloroethan interface involves the cotransfer of three hydration shell water molecules, independent of the surface tension. However, as the interaction between the two liquids weakens, a rise in interfacial tension and decrease in intrinsic water fingering and capillary fluctuations result in fewer water molecules cotransported with the ion in the second shell and a reduction in the length of the finger that the ion is attached to, consistent with the reduced size of the second hydration shell. First shell water residence time and lateral ion diffusion constants vary with the surface tension in a way that is consistent with the abovementioned structural insight.

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“…Several authors have 2 International Journal of Electrochemistry used computer simulations to model the interface and the ion transfer processes (vide infra, Section 4). Several reports using molecular dynamic simulations showed that ion transfer into the organic phase is accompanied by a hydration shell of water molecules [47,57,65,70,[74][75][76][77].…”

Section: Introductionmentioning

confidence: 99%

Simple Ion Transfer at Liquid|Liquid Interfaces

Vallejo

Ovejero

Fernández

et al. 2012

International Journal of Electrochemistry

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The main aspects related to the charge transfer reactions occurring at the interface between two immiscible electrolyte solutions (ITIES) are described. The particular topics to be discussed involve simple ion transfer. Focus is given on theoretical approaches, numerical simulations, and experimental methodologies. Concerning the theoretical procedures, different computational simulations related to simple ion transfer are reviewed. The main conclusions drawn from the most accepted models are described and analyzed in regard to their relevance for explaining different aspects of ion transfer. We describe numerical simulations implementing different approaches for solving the differential equations associated with the mass transport and charge transfer. These numerical simulations are correlated with selected experimental results; their usefulness in designing new experiments is summarized. Finally, many practical applications can be envisaged regarding the determination of physicochemical properties, electroanalysis, drug lipophilicity, and phase-transfer catalysis.

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Molecular dynamics study of hydrated alkali and halide ions in liquid nitrobenzene

Cited by 14 publications

References 34 publications

Uranyl Speciation in the Presence of Specific Ion Gradients at the Electrolyte/Organic Interface

Uranyl Speciation in the Presence of Specific Ion Gradients at the Electrolyte/Organic Interface

Molecular Dynamics Studies on the Effect of Surface Roughness and Surface Tension on the Thermodynamics and Dynamics of Hydronium Ion Transfer Across the Liquid/Liquid Interface

Simple Ion Transfer at Liquid|Liquid Interfaces

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