N,N,N′,N′-tetraoctyldiglycolamide (TODGA), in n-dodecane, effectively separates trivalent metal ions but triggers early third-phase formation in the presence of higher metal ion concentrations from nitric acid. To mitigate this, N,N-dioctyl-2-hydroxyacetamide (DOHyA), a phase modifier for TODGA, forms a combined solvent system composed of TODGA+DOHyA/n-DD (n-DD = n-dodecane), which efficiently separates trivalent metal ions from radioactive waste. However, understanding the physicochemical behavior and radiolytic stability of this solvent before industrial-scale application is crucial. Hence, this study investigates the density and viscosity of TODGA+DOHyA/n-DD and the results obtained were compared with the individual systems. The results revealed a decrease in viscosity and density with increasing temperatures at all doses, and the solvents follow the trend as 0.15 mol kg^–1 of TODGA + 0.29 mol kg^–1 of DOHyA/n-DD > TODGA/n-DD > DOHyA/n-DD. In addition, although the density and viscosity increases with the gamma dose in all systems, TODGA + DOHyA/n-DD displays minimal change, signifying exceptional stability under irradiation. Thermodynamic parameters revealed weak molecular interactions in TODGA + DOHyA/n-DD. In summary, this study highlights the stability of TODGA + DOHyA/n-DD, with minor density and viscosity changes under irradiation, spotlighting its potential for nuclear reprocessing.

中文翻译：

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TODGA-DOHyA：对核后处理稳定溶剂系统的物理化学见解

正十二烷中的N,N,N',N'-四辛基二甘醇酰胺 (TODGA)可有效分离三价金属离子，但在硝酸中金属离子浓度较高的情况下会引发早期第三相形成。为了缓解这一问题， TODGA 的相改性剂N,N -二辛基-2-羟基乙酰胺 (DOHyA) 形成了由 TODGA+DOHyA/ n -DD ( n -DD = n -十二烷) 组成的组合溶剂系统，可有效分离来自放射性废物的三价金属离子。然而，在工业规模应用之前了解这种溶剂的物理化学行为和辐射分解稳定性至关重要。因此，本研究研究了 TODGA+DOHyA/ n -DD的密度和粘度，并将所得结果与各个系统进行了比较。结果显示，在所有剂量下，粘度和密度随着温度的升高而降低，并且溶剂遵循以下趋势：0.15 mol kg ^–1 TODGA + 0.29 mol kg ^–1 DOHyA/ n -DD > TODGA/ n -DD > DOHyA / n -DD。此外，尽管所有系统中的密度和粘度都随着伽马剂量的增加而增加，但 TODGA + DOHyA/ n -DD 的变化很小，这表明在辐照下具有出色的稳定性。热力学参数揭示了 TODGA + DOHyA/ n -DD 中较弱的分子相互作用。总之，本研究强调了 TODGA + DOHyA/ n -DD 的稳定性，在辐照下密度和粘度变化较小，突出了其用于核后处理的潜力。