Dimethyl Dibutyl Research Articles

Understanding the complexation of the Eu3+ ion with TODGA, CMPO, TOPO and DMDBTDMA: Extraction, luminescence and theoretical investigation

A comparative study was carried out to understand the complexation behavior of the Eu3+ ion with important reagents, namely TODGA (N,N,N′,N′ tetraoctyl diglycolamide), CMPO (octyl (phenyl)-N, N-diisobutyl carbamoyl methyl phosphine oxide), DMDBTDMA (dimethyl dibutyl tetradecyl malonamide) and TOPO (tri-n-octyl phosphine oxide) in dodecane, used for the separation of actinides and lanthanides from lab and nuclear high-level wastes, by experimental (extraction and luminescent) and theoretical means. A solvent extraction study revealed the metal–ligand stoichiometry as 1:3 for all the systems with the extraction efficiency TOPO>CMPO>TODGA>DMDBTDMA at 1M HNO3, while TODGA>CMPO>DMDBTDMA>TOPO at 3M HNO3. A luminescence investigation revealed the presence of single species in the extracted complex for all the systems, with no inner sphere water molecules for all the systems except for DMDBTDMA which had one inner sphere water molecule. The high intensity of the 5D0–7F2 transition revealed the presence of Eu3+ ions in an asymmetric environment with the local point group symmetry C3v for the TODGA and DMDBTDMA complexes, compared to C3h symmetry for the CMPO and TOPO complexes. Judd–Offelt parameters, radiative, non-radiative lifetimes, branching ratio, transition probabilities and quantum efficiencies for all the complexes were estimated and compared. Three O-donor atoms from each TODGA molecule coordinated to the Eu3+ ion in the first coordination sphere, while three CMPO units were found to be coordinated in a monodentate fashion. For the Eu-TOPO complex, three O donor atoms from each of the three TOPO molecules and six O donor atoms from three nitrate ions were coordinated. Out of three DMDBTDMA ligands, one was found to be coordinated in a bidentate mode, whereas two were in a monodentate mode, along with three nitrate ligands bonding in a monodentate fashion.

Extraction of actinides using N, N, N′, N′-tetraoctyl diglycolamide (TODGA): a thermodynamic study

Summary The effect of temperature on the extraction behaviour of Am(III), Pu(IV) and U(VI) from nitric acid medium was studied employing N,N,N′,N′-tetraoctyl diglycolamide (TODGA) in n-dodecane. The two-phase equilibrium constants (log K′ex) were calculated and compared with those of other extractants proposed for actinide partitioning, viz. octyl-(phenyl)-N,N-diisobutylcarbamoylmethyl phosphine oxide (CMPO) and N,N,N′,N′-dimethyl dibutyl tetradecyl malonamide (DMDBTDMA). Thermodynamic parameters, viz. ΔG, ΔH and ΔS for the extraction of actinides by TODGA were also compared with those of CMPO and DMDBTDMA. These studies indicate that the extraction processes of Am(III) and U(VI) are enthalpy driven whereas entropy factor counteracts the extraction. However, in the case of Pu(IV), the extraction process is enthalpy as well as entropy favoured. Role of diluent on the loading of Nd(III) in 0.1 M TODGA has also been investigated.

Amides and diamides as promising extractants in the back end of the nuclear fuel cycle: an overview

Abstract An overview of the work carried out on the development of amides/diamides as alternate extractants in the back end of fuel cycle has been given. Whereas a straight chain amide, viz. N,N-dihexyl octanamide (DHOA) is a promising alternate to tri-n-butyl phosphate (TBP) in the reprocessing of irradiated uranium-based fuels, a branched chain amide, viz. N,N-di(2-ethylhexyl) isobutyramide (D2EHIBA) has been found suitable for the selective recovery of 233 U from irradiated Th. DHOA has been found to extract Pu more efficiently than TBP under uranium loading conditions. On the other hand, significant improvement in the separation of 233 U from Th and fission products has been achieved by employing 0.5 M D2EHIBA in n-dodecane as compared to that of 5% TBP (the THOREX solvent). Stripping behaviour of U for DHOA and D2EHIBA is better than that of TBP. N,N′,N,N′-dimethyl dibutyl tetradecyl malonamide (DMDBTDMA) has been evaluated for the partitioning of minor actinides (MA) from high-level nuclear waste with large uranium content (∼20 g/l). Designed amide ligands, viz. D2EHIBA showed improved separation of the desired actinide constituents like Pu (mainly 239 Pu ) and 233 U over the fission products and the major matrix elements like U and Th.

Uptake of Metal Ions by Extraction Chromatography Using Dimethyl Dibutyl Tetradecyl-1,3-malonamide (DMDBTDMA) as the Stationary Phase

The uptake of several actinides and fission products such as U(VI), Pu(IV), Am(III), Eu(III), Cs(I), and Sr(II) from nitric acid solutions by a novel extraction chromatographic resin containing dimethyl dibutyl tetradecyl-1,3-malonamide (DMDBTDMA) has been investigated. The order of uptake follows the order Pu(IV) U(VI) Am(III) ∼ Eu(III) Sr(II) ∼ Cs(I). The possibility of this resin material sorbing trace concentrations of actinide ions from nitric acid solutions containing relatively larger amounts of Nd(III) and U(VI), as well as from simulated pressurized heavy water reactor (PHWR) waste solution, has been evaluated. The uptake of Am(III) in the presence of NaNO3, as well as in the presence of a macro concentration of Fe(III), has been investigated. The capacity of the resin for Am(III) and the elution behavior of the actinide ions from the resin were also studied.

Preparation and characterization of poly(N-hexyl-pyrrole 2N,N'-dimethyl dibutyl malonamide) thin films exhibiting chelating properties. Application to the chemical fixation of actinide elements

Une nouvelle methode de preparation de sources minces radioactives est basee sur deux etapes: - (1) la preparation de films minces et - (2) l'incorporation d'elements radioactifs par un procede de chelation. Nous presentons quelques proprietes du monomere N-hexyl-pyrrole 2N,N'dimethyl dibutyl malonamide. Les films minces sont obtenus par electropolymerisation de ce monomere dans l'acetonitrile. Cette methode permet la synthese de polymeres d'epaisseur controlee contenant des ligands chelatants. Le coefficient de distribution limite et le rendement de fixation ont ete determines pour l'uranium(VI) dans un milieu nitrique de trempage.

EXTRACTION BY N,N,N',N-TETRAALKYL -2 ALKYL PROPANE -1,3 DIAMIDES. I. H2O, HNO3and HClO4

ABSTRACT The extracting properties of substituted diamides were investigated. The auto-association of N,N'-dimethyl dibutyl tetradecyl malonamide (DMDBTDMA) : (C4H9(CH3)NCO)2CHC14H29 in benzene and in TPH (aliphatic hydrocarbon) was shown by NMR using mass-action model. The degree of aggregation depends on the diluent, the diamide concentration and the acidity. The extraction of HNO3 and HClO4 was investigated by distribution measurements and IR spectroscopy. HNO3 extraction is explained by the competing formation of four adducts : whose the equilibrium constants for 0,72 mol.l-1 amide in TPH are 0.167, 0.215, 5.19-10-3 and 3.7-10-4, respectively, on a molal scale. HClO4 is extracted by a reaction involving the competing formation of the two adducts . Their equilibrium constants for 0.697 mol.1-1 amide in TPH are 0.649 and 1.71, respectively, on a molal scale. V(C=O) IR absorption shifts indicate that in are linked by hydrogen bonds, whereas in is transferred from one molecule of acid to one C=O of the DM...