Radiolytic stability ofN,N-dialkyl amide: effect on Pu(iv) complexes in solution

Abstract

The radiolytic degradation of three N,N-dialkyl amide ligands relevant to nuclear fuel reprocessing was studied. The degradation of these ligands: N,N di-2-ethyhexylbutyramide (DEHBA), N,N di-2-ethyhexylisobutyramide (DEHiBA) and N,N di-2-ethyhexyl-3-dimethylbutanamide (DEHDMBA) was examined to evaluate the effect of the structure on the formation of degradation products as well as to compare alpha induced degradation to gamma induced degradation. In situ alpha radiolysis by introduction of plutonium(iv) as the alpha source in the solution and ex situ gamma radiolysis with Co as the gamma source were compared. Upon identification of the main degradation products, a degradation scheme was proposed. The effects of radiation on the stability of Pu-monoamide complexes were discussed. Theoretical calculations were also performed to determine bond dissociation energy and estimate the relative strength of the bond in the molecule. The results show that neither the type of radiation (alpha vs. gamma) nor the structure modification (introduction of branching on the alkyl chain off the carbonyl carbon) of the molecule significantly impact the formation of degradation products under the conditions studied. Moreover, it was observed that the overall stability of the monoamide remains good and that Pu complexation is not greatly affected by either alpha or gamma irradiation.

Effect of metal complexation on diglycolamide radiolysis: a comparison between ex situ gamma and in situ alpha irradiation

“…ESI-MS generally used to identify organic compounds in solution can also be used to probe metallic complexes existing in solution. 60,[83][84][85][86][87][88][89][90][91][92][93][94][95] The ESI-MS spectrum was collected for each TODGA-Am solution in order to identify the species coming from the free ligand or being involved in metallic complexes. The main species identified before degradation in these systems are the free ligand and Am spcies.…”

Effects of Gamma Irradiation on the Extraction Properties of Innovative Stripping Solvents for i-SANEX/GANEX Processes

“…The solution of 241 Am­(NO 3 ) 3 in 1 mol/L HNO 3 , used at Politecnico di Milano, was supplied by Eurostandard CZ (Czech Republic). Meanwhile, the radioactive solutions containing 239 Pu­(IV), 241 Am­(III), and 244 Cm­(III) used at the CEA laboratory were prepared by dissolving weighed amounts of the respective oxides in HNO 3 , followed by careful purification by using ion-exchange chromatography and verification of the oxidation state by using UV–vis spectrophotometry, as described elsewhere. − In particular, the composition of these stock solutions was as follows: 0.017% 238 Pu, 96.91% 239 Pu, 2.99% 240 Pu, 0.065% 241 Pu, and 0.009% 242 Pu for Pu; 98.74% 241 Am, <0.02% 242 Am, and 1.25% 243 Am for Am; and mainly 244 Cm for Cm. The TODGA ligand was provided by the Institute for Nuclear Waste Disposal at the Karlsruhe Institute of Technology, Germany.…”

Alpha radiolysis of DOTA ligand in aqueous solutions with helium ion beams

“…Almost a third of DOTA was degraded after irradiation with a dose of 110 kGy. In order to identify the degradation products, electrospray ionization mass spectrometry (ESI-MS), which is a highly sensitive technique for the identification of organic degradation products in relatively low concentration, was used (Drader et al, 2017(Drader et al, , 2018. In the case of the DOTA molecule, as for polyaminocarboxylic acid, both positive and negative ionization mode can be used (Künnemeyer et al, 2008(Künnemeyer et al, , 2009Audras et al, 2014;Zarzana et al, 2015).…”