Dielectric Behavior of Aqueous Binary Mixtures of Hydrophobic Solutes

Prabhu, P. V. S. S.; Ramanamurti, M. V.

doi:10.1246/bcsj.65.1716

Cited by 7 publications

(2 citation statements)

References 12 publications

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“…The SPC-E with a modified TraPPE model is closer to the experimental values [47], compared with the TIP4P-Ew. Another set of experimental data concerning ∆ε mix dependence on composition was reported in [53]. Again, the minimum value of the excess mixing static dielectric constant was observed at X dme ≈ 0.3.…”

Section: Self-diffusion Coefficients and The Dielectric Constantmentioning

confidence: 85%

Isobaric-isothermal molecular dynamics computer simulations of the properties of water-1,2-dimethoxyethane model mixtures

Gujt¹,

Domínguez²,

Sokołowski³

et al. 2017

Condens. Matter Phys.

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Isothermal-isobaric molecular dynamics simulations have been performed to examine a broad set of properties of the model water-1,2-dimethoxyethane (DME) mixture as a function of composition. The SPC-E and TIP4P-Ew water models and the modified TraPPE model for DME were applied. Our principal focus was to explore the trends of behaviour of the structural properties in terms of the radial distribution functions, coordination numbers and number of hydrogen bonds between molecules of different species, and of conformations of DME molecules. Thermodynamic properties, such as density, molar volume, enthalpy of mixing and heat capacity at constant pressure have been examined. Finally, the self-diffusion coefficients of species and the dielectric constant of the system were calculated and analyzed.

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Section: Self-diffusion Coefficients and The Dielectric Constantmentioning

confidence: 85%

Isobaric-isothermal molecular dynamics computer simulations of the properties of water-1,2-dimethoxyethane model mixtures

Gujt¹,

Domínguez²,

Sokołowski³

et al. 2017

Condens. Matter Phys.

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show abstract

“…The measurements of the excess dielectric constant also show strong deviation from ideal mixture behavior, including a maximum at X DME = 0.32 . The authors also tried to explain this behavior by formation of clusters.…”

Section: Theory Experiment and Previous Simulationsmentioning

confidence: 88%

Molecular Dynamics Simulations of 1,2-Dimethoxyethane/Water Solutions. 1. Conformational and Structural Properties

1998

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Molecular dynamics simulations of solutions of 1,2-dimethoxyethane (DME) and water have been performed in order to investigate the conformations of DME and the local solution structure as a function of solution composition and temperature. The simulations employ a previously developed force field based upon ab initio quantum chemistry calculations of DME/water interactions. The DME conformer populations show a strong dependence on temperature and solution composition and are quite different in aqueous solutions from those found in the gas phase or neat liquid. An analysis of the dependence of the conformer population distribution on temperature allows us to estimate the relative free energies of solvation for different conformers in water solution, which are found to be primarily energetic in origin for dilute solutions. The conformation dependence of the solvation free energy, resulting in "hydrophilic" and "hydrophobic" conformers, is explained in terms of differences in polar interactions between DME and neighboring water molecules. Analysis of the local structure of water around different DME conformers reveals that the degree of DME/water hydrogen bonding is nearly independent of the DME conformer for dilute solutions. The extent of water/water hydrogen bonding is also found to be nearly independent of composition over a wide composition range. To maintain a nearly constant level of water-water hydrogen bonding with increasing DME concentration, water is not randomly distributed in the system on a nearest-neighbor length scale but rather tends to form clusters of 4-5 molecules. The entropic penalty associated with this water structure increases with increasing DME concentration and temperature, thereby increasing the free energy of hydrophilic conformers relative to hydrophobic conformers.

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Solvatochromism in Alcohol‐Water Mixtures: Effects of the Molecular Structure of the Probe

Novaki

Seoud

1997

Ber Bunsenges Phys Chem

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Solvatochromic behavior of 2,6‐diphenyl‐4‐(2,4,6‐triphenyl‐1‐pyridinio)‐1‐phenolate (RB), 1‐methyl‐8‐oxyquinolinium betaine (QB), sodium 1‐methyl‐8‐oxyquinolinium betaine‐5‐sulphonate (QBS), and 1‐methyl‐3‐oxypyridinium betaine (PB) was studied UV/Vis spectrophotometrically in binary mixtures of water with methanol, ethanol, 1‐propanol, 2‐methyl‐2‐propanol, ethane‐1,2‐diol, 2‐methoxyethanol, and 2‐n‐butoxyethanoI. The solvent polarity parameter, ET (in kcal/mole), was calculated from the position of the longest‐wavelength absorption band of the solvatochromic probe, and was then correlated with χw, the mole fraction of water in the mixture. Except for PB in aqueous methanol, aqueous ethanol and aqueous 1‐propanol, plots of ET versus χw are not linear because of preferential solvation of the probe by one component of the mixed solvent and, when applicable, because of solvent microheterogeneity. In the same aqueous alcohol mixtures, deviation from linearity in the ET versus χw plots increases as a function of the increasing hydrophobic character of the probe. For the same solvatochromic probe in different aqueous mixtures, the above mentioned deviation increases as a function of increasing the chain length of the alcohol. Preferential solvation of the probe is described in terms of the so called “solvent fractionation factor, ϕs”, whose value indicates the relationship between composition of the solvation shell of the probe, and composition of the bulk solvent. In the absence of solvent microheterogeneity, all values of ϕs are less than unity, which indicates preferential solvation of the probe molecule by the alcohol. An attempt to evaluate contributions from preferential solvation and solvent microheterogeneity to solvatochromism in aqueous methanol, and aqueous THF showed that the approach used by Park et al. [J. Phys. Org. Chem. 7, 757 (1994)] is not applicable.

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Dielectric Behavior of Aqueous Binary Mixtures of Hydrophobic Solutes

Cited by 7 publications

References 12 publications

Isobaric-isothermal molecular dynamics computer simulations of the properties of water-1,2-dimethoxyethane model mixtures

Isobaric-isothermal molecular dynamics computer simulations of the properties of water-1,2-dimethoxyethane model mixtures

Molecular Dynamics Simulations of 1,2-Dimethoxyethane/Water Solutions. 1. Conformational and Structural Properties

Solvatochromism in Alcohol‐Water Mixtures: Effects of the Molecular Structure of the Probe

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