Correlation of excess enthalpies of mixing in tributylphosphate-N-alkane system

Tsimering, L.; Kertes, A.S.

doi:10.1016/0040-6031(75)85031-3

Cited by 6 publications

(4 citation statements)

References 2 publications

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“…Since the ∠O2PO2 angle is less than 90°, the arrangement in Figure d provides favorable electrostatic interaction between two TBP molecules with the two TBP dipoles in antiparallel alignment with the positively charged P and the negatively charged O2 closest to each other. Thus, the geometry from MD simulation provides an explicit realization for the TBP molecule dimerization conjectured from a variety of experimental evidence. − …”

Section: Resultsmentioning

confidence: 97%

“…An analysis of the PCFs is also useful from a theoretical perspective in providing insight into macroscopic properties of the system as well as how molecules interact in the liquid state bulk phase. Based on a host of experimental techniques, namely, distribution coefficient experiments, infrared spectroscopy, nuclear magnetic resonance, calorimetry, − and vapor pressure osmometry, , it has been suggested that TBP in liquid environment has a tendency for self-association. More recently, Motokawa et al have carried out X-ray and neutron scattering experiments on TBP/ n -octane mixture, and reported observing a peak in X-ray scattering intensity at wave vector q ≈ 0.63–0.68 (corresponding to a wavelength of λ = 2π/ q ≈ 0.94–0.98 nm) which the authors attributed to the average P–P distance in the mixture.…”

Section: Resultsmentioning

confidence: 99%

“…The investigation of TBP and its mixture has led to the probing of molecular level behaviors. In particular, a variety of experiments, such as, distribution coefficient experiments, infrared spectroscopy, nuclear magnetic resonance, calorimetry, − and vapor pressure osmometry, , have been carried out to study the self-association of TBP molecules in the liquid environment.…”

Section: Introductionmentioning

confidence: 99%

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Molecular Dynamics Simulations of Tri-n-butyl-phosphate/n-Dodecane Mixture: Thermophysical Properties and Molecular Structure

2014

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Molecular dynamics simulations of tri-n-butyl-phosphate (TBP)/n-dodecane mixture in the liquid phase have been carried out using two recently developed TBP force field models (J. Phys. Chem. B 2012, 116, 305) in combination with the all-atom optimized potentials for liquid simulations (OPLS-AA) force field model for n-dodecane. Specifically, the electric dipole moment of TBP, mass density of the mixture, and the excess volume of mixing were computed with TBP mole fraction ranging from 0 to 1. It is found that the aforementioned force field models accurately predict the mass density of the mixture in the entire mole fraction range. Commensurate with experimental measurements, the electric dipole moment of the TBP was found to slightly increase with the mole fraction of TBP in the mixture. Also, in accord with experimental data, the excess volume of mixing is positive in the entire mole fraction range, peaking at TBP mole fraction range 0.3-0.5. Finally, a close examination of the spatial pair correlation functions between TBP molecules, and between TBP and n-dodecane molecules, revealed formation of TBP dimers through self-association at close distance, a phenomenon with ample experimental evidence.

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Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Molecular Dynamics Simulations of Tri-n-butyl-phosphate/n-Dodecane Mixture: Thermophysical Properties and Molecular Structure

2014

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“…Osseo-Asare reviewed the experimental evidence, reported before 1991, of the existence of self-associated species in TBP/diluent systems. − The self-association of TBP has been observed by various experimental techniques including partitioning studies, infrared spectroscopy, nuclear magnetic resonance, calorimetry, − and vapor pressure osmometry . These experiments revealed that the self-association of TBP is attributable to dipole–dipole interactions involving the PO groups of the phosphate ester mediated by hydrogen bonding with water, forming TBP dimers. ,− ,− Moreover, in that review on TBP–diluent/H 2 O–acid–metal ion extraction systems, Osseo-Asare proposed that the TBP–acid–metal ion complex consists of a high-order assembly (reverse micelle or microemulsion) in organic diluents.…”

Section: Introductionmentioning

confidence: 99%

Microscopic Structures of Tri-n-butyl Phosphate/n-Octane Mixtures by X-ray and Neutron Scattering in a Wide q Range

et al. 2012

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Tri-n-butyl phosphate (TBP) is an important extractant for separating hexavalent uranium and tetravalent plutonium from used nuclear fuel by solvent extraction. In such solvent extractions using TBP, the organic phase occasionally separates into two organic phases, namely, light and heavy organic phases. The latter one in particular is called the third phase. The purpose of this work is to elucidate the mechanism whereby the third phase forms in biphasic liquid-liquid solvent extraction of heavy metal ions. Toward this end, small- and wide-angle X-ray and neutron scattering (SWAXS and SWANS) experiments were conducted to examine the microscopic structures of TBP/octane mixtures. These investigations of solute associations in TBP-containing organic phases before extraction of heavy metal ions provide insights into system performance. After the extraction of heavy metal ions, for example, the microscopic structures formed in the organic phase are likely to be correlated with the initial microscopic structures, which are revealed here. SWAXS and SWANS, with accurate estimations of incoherent scattering intensities for all solution samples, revealed the following: (i) TBP self-associates in octane, and the average distance between two TBP molecules in the TBP assemblies is evaluated as 0.9-1.0 nm; (ii) the shape of the TBP assembly is ellipsoidal; and (iii) the attractive interaction among TBP assemblies in octane is miniscule, and thus, they tend to be dispersed homogeneously due to the excluded volume effect.

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The enthalpies of mixing of organophosphate esters with hydrocarbons

Marcus

Kolařík

1977

J Solution Chem

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Correlation of excess enthalpies of mixing in tributylphosphate-N-alkane system

Cited by 6 publications

References 2 publications

Molecular Dynamics Simulations of Tri-n-butyl-phosphate/n-Dodecane Mixture: Thermophysical Properties and Molecular Structure

Molecular Dynamics Simulations of Tri-n-butyl-phosphate/n-Dodecane Mixture: Thermophysical Properties and Molecular Structure

Microscopic Structures of Tri-n-butyl Phosphate/n-Octane Mixtures by X-ray and Neutron Scattering in a Wide q Range

The enthalpies of mixing of organophosphate esters with hydrocarbons

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