FTIR spectroscopic investigations on the aggregation behaviour of N,N,N′,N′-tetraoctyldiglycolamide and N,N-dioctylhydroxyacetamide in n-dodecane during the extraction of Nd(III) from nitric acid medium

A multi-faceted approach to probe organic phase composition in TODGA systems with 1-alcohol phase modifiers

“…As the Ln-DGA complex C O frequency is red-shifted, this indicates a weaker C O bond associated with the Ln-DGA complex compared to the stronger C O bond in the (DGA)(HNO 3 ) 1-2 adducts. 33 This behavior is not isolated to the systems considered herein, but has been reported with DOHyA, 33 D 3 DODGA, 38 T2EHDGA, 39 TODGA, 33 TODGA (+DHOA), 40 TODGA (+1-octanol), 40 and TODGA (+DOHyA) 33 systems. These studies involved increasing the concentration of Nd at constant extractant and HNO 3 concentrations, where higher Nd concentrations resulted in larger Ds.…”

“…A complete shift of C O stretches, has been correlated with TPF, where polar–polar interactions of the extracted species dominate the solution. 33 Across the Ln period, the LOC decreases, 15 suggesting the behavior observed in FT-IR carbonyl intensities might be a product of organic phase micro-structure approaching that found in TPF.…”

“…This is consistent with previous TODGA and T2EHDGA literature values for the C]O stretch. 30,33,34 Upon the addition of 5 vol% 1-alcohol, 1-hexanol and 1-decanol have a shoulder that is red-shied in comparison to the C]O stretch of the no modier system. A red shi (or decreasing frequency) is observed when the C]O bond, in this case, weakens.…”

TODGA-DOHyA: Physicochemical Insights into a Stable Solvent System for Nuclear Reprocessing

“…In view of this, diglycolamides (DGAs), a class of extractants, were studied extensively and were found to be suitable candidates for the partitioning of trivalent metal ions from HLLW. − Among these, N,N,N’N’ -tetraoctyldiglycolamide (TODGA) in a nonpolar diluent, n -dodecane ( n -DD), was considered as a promising system for the partitioning of trivalent f-ions from the HLLW. ,, However, it has certain limitations such as early third-phase formation when contacted with higher concentrations of nitric acid and/or trivalent metal ions from nitric acid. In this view, several researchers have proposed various methods to prevent third-phase formation during the solvent extraction procedure. ,− The addition of phase modifiers to the extractant system has been found to be one of the effective options for the prevention of third-phase formation. − N,N -dioctyl hydroxyl acetamide (DOHyA) serves as a good phase modifier for the TODGA/ n -DD system during the extraction of trivalent metal ions from HLLW via solvent extraction procedure. − The structures of TODGA and DOHyA are shown in Figure .…”

“…These physical properties of the solvent are likely to be affected upon radiolysis, which may affect the performance of the solvent systems toward the separation of metal ions. − Hence the stability of the solvent system toward radiation is one of the important property to be investigated to be employed for the separation of minor trivalent actinides from high active nuclear waste. Extensive studies on the solvent extraction and third-phase formation behavior of 0.15 mol kg –1 of TODGA and 0.29 mol kg –1 of DOHyA in n -DD toward trivalent metal ions is already reported. , However, the physico-chemical properties and their variation as a function of the absorbed dose are limited in the literature. Hence, the aim of the present investigation is to determine the physico-chemical behavior of the combined solvent system (0.15 mol kg –1 of TODGA and 0.29 mol kg –1 of DOHyA in n -DD) at various temperatures and absorbed gamma doses.…”