Effect of temperature, radiation dose and composition on density, viscosity and volumetric properties of N,N,N′,N′-tetraoctyl diglycolamide (TODGA) and n-dodecane mixture, a promising system for the separation of actinides

Ravi, Jammu; Mishra, Satyabrata; Murali, Remya; Desigan, N.; Pandey, N. K.

doi:10.1007/s10967-021-07724-w

Cited by 9 publications

(21 citation statements)

References 28 publications

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“…A pure TODGA system containing 800 molecules was simulated at 1 bar and 298.15 K as described previously, except that a production run of 20 ns was found to be sufficient. The average density was 0.9373 ± 0.0003 g cm –3 as opposed to experimental values for pure TODGA of 0.910 g cm –3 …”

Section: Resultscontrasting

confidence: 65%

“…The average density was 0.9373 ± 0.0003 g cm −3 as opposed to experimental values for pure TODGA of 0.910 g cm −3 . 82 The system size dependence of this result was found to be negligible. No doubt, the forcefield could be adjusted to give closer agreement with the experimental density, but considerably more experimental data are required to do such a fit reliably.…”

Section: ■ Resultsmentioning

confidence: 83%

“…The average density was 0.9373 ± 0.0003 g cm –3 as opposed to experimental values for pure TODGA of 0.910 g cm –3 . 82 …”

Section: Resultsmentioning

confidence: 99%

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Molecular Dynamics Study of the Aggregation Behavior of N,N,N′,N′-Tetraoctyl Diglycolamide

et al. 2022

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Liquid–liquid extraction is a commonly used technique to separate metals and is a process that has particular relevance to the nuclear industry. There has been a drive to use environmentally friendly ligands composed only of carbon, hydrogen, nitrogen, and oxygen. One example is the i-SANEX process that has been developed to separate minor actinides from spent nuclear fuel. The underlying science of such processes, is, however, both complex and intriguing. Recent research indicates that the liquid phases involved are frequently structured fluids with a hierarchical organization of aggregates. Effective flow-sheet modeling of such processes is likely to benefit from the knowledge of the fundamental properties of these phases. As a stepping stone toward this, we have performed molecular dynamics simulations on a metal free i-SANEX system composed of the ligand N , N , N ′, N ′-tetraoctyl diglycolamide (TODGA), diluent hydrogenated tetrapropylene (TPH), and polar species water and nitric acid. We have also studied the effects of adding n -octanol and swapping TPH for n -dodecane. It would seem sensible to understand this simpler system before introducing metal complexes. Such an understanding would ideally arise from studying the system’s properties over a wide range of compositions. The large number of components, however, precludes a comprehensive scan of compositions, so we have chosen to study a fixed concentration of TODGA while varying the concentrations of water and nitric acid over a substantial range. Reverse aggregates are observed, with polar species in the interior in contact with the polar portions of the TODGA molecules and the organic diluent on the exterior in contact with the TODGA alkyl chains. These aggregates are irregular in shape and grow in size as the amount of water and nitric acid increases. At a sufficiently high polar content, a single extended cluster forms corresponding to the third phase formation. No well-defined bonding motifs were observed between the polar species and TODGA. The cluster size distribution fits an isodesmic model, where the Gibbs energy change of adding a TODGA molecule to a cluster ranges between 4.5 and 7.0 kJ mol –1 , depending on the system composition. The addition of n -octanol was found to reduce the degree of aggregation, with n -octanol acting as a co-surfactant. Exchanging the diluent TPH for n -dodecane also decreased the aggregation. We present evidence that this is due to the greater penetration of n -dodecane into the reverse aggregates. It is known, however, that the propensity for the third phase formation is greater with n -dodecane as the diluent than is the case with TPH, but we argue that these two results are not contradictory. This research casts light on the drivin...

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Section: Resultscontrasting

confidence: 65%

Section: ■ Resultsmentioning

confidence: 83%

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Molecular Dynamics Study of the Aggregation Behavior of N,N,N′,N′-Tetraoctyl Diglycolamide

et al. 2022

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“…[32][33][34] The changes in the physicochemical properties and aggregation behaviour of the radiolytically degraded organic phase are likely to pose a number of problems in the industrial scale solvent extraction procedure. 34,35 In contrast, most of the studies reported in the literature focus only on the extraction and stripping behaviour of actinides and lanthanides, variation in the physical properties of the radiolytically degraded organic phase and characterisation of degraded products. [30][31][32][33][34][35] The studies related to the reverse micellar aggregation behaviour of the irradiated organic phase containing DGAs in n-DD and how the degradation products present in the organic phase affect the polarity of aggregates are scarce.…”

Section: Introductionmentioning

confidence: 99%

“…34,35 In contrast, most of the studies reported in the literature focus only on the extraction and stripping behaviour of actinides and lanthanides, variation in the physical properties of the radiolytically degraded organic phase and characterisation of degraded products. [30][31][32][33][34][35] The studies related to the reverse micellar aggregation behaviour of the irradiated organic phase containing DGAs in n-DD and how the degradation products present in the organic phase affect the polarity of aggregates are scarce. 11,13,31 In view of this, the primary objective of the present work is to understand the reverse micellar aggregation behaviour of the irradiated diglycolamide in n-dodecane solution.…”

Section: Introductionmentioning

confidence: 99%

The fate of reverse micellar aggregation in irradiated diglycolamide inn-dodecane solution

Parvathy

Prathibha

et al. 2023

New J. Chem.

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Feasibility of using the mixture of two symmetrical diglycolamides instead of unsymmetrical diglycolamide solvent for the separation of trivalent actinides

Ravi

Parvathy

Desigan

et al. 2023

J Radioanal Nucl Chem

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Effect of temperature, radiation dose and composition on density, viscosity and volumetric properties of N,N,N′,N′-tetraoctyl diglycolamide (TODGA) and n-dodecane mixture, a promising system for the separation of actinides

Cited by 9 publications

References 28 publications

Molecular Dynamics Study of the Aggregation Behavior of N,N,N′,N′-Tetraoctyl Diglycolamide

Molecular Dynamics Study of the Aggregation Behavior of N,N,N′,N′-Tetraoctyl Diglycolamide

The fate of reverse micellar aggregation in irradiated diglycolamide inn-dodecane solution

Feasibility of using the mixture of two symmetrical diglycolamides instead of unsymmetrical diglycolamide solvent for the separation of trivalent actinides

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