Assessment of ligand extraction properties: an intercomparison campaign amongst EUROPARTners

Abstract

An intercomparison campaign was organized at the beginning of the European FP6 EUROPART Integrated Project, among the partners involved in the assessment of the extracting properties of novel ligands, in order to check their accuracy and reliability when determining metal cation distribution ratios. Three different extracting systems, presenting various selectivity and affinity towards trivalent actinides were selected: (i) CMPO, (ii) TPTZ and (iii) BTP. Although some differences could be pointed out in the implementation of liquid-liquid extraction tests, the distribution ratios measured by the nine partners were fairly reproducible (< 20% deviation) for the first two extracting systems. However, large discrepancies occurred when testing the third extracting system, due to its strong hydrolytic instability, thus pointing out the difficulty of assessing extraction properties of instable ligands.

2,6-Bis(5-(2,2-dimethylpropyl)-1H-pyrazol-3-yl)pyridine as a Ligand for Efficient Actinide(III)/Lanthanide(III) Separation

“…The separation factor is SF Am(III)/Eu(III) = D Am(III) / D Eu(III) . Distribution ratios (which were 10 –3 < D < 10 3 , see Results and Discussion) typically are reproducible within ±20% …”

“…241 Distribution ratios (which were 10 −3 < D < 10 3 , see Results and Discussion) typically are reproducible within ±20%. 42 TRLFS Titration. The TRLFS titration experiments were performed using a stock solution of 6.67 × 10 −6 mol/L Cm(III) (89.7% 248 Cm, 0.1% 247 Cm, 9.4% 246 Cm, 0.1% 245 Cm, 0.3% 244 ■ RESULTS AND DISCUSSION Ligand Synthesis.…”

6-(3,5-Dimethyl-1H-pyrazol-1-yl)-2,2′-bipyridine as Ligand for Actinide(III)/Lanthanide(III) Separation

“…Distribution ratios usually are reproducible within ±20% . Distribution ratios outside the range of 10 −3 < D < 10 3 may bear significantly larger errors and should be regarded with caution.…”

Complexation and Extraction of Trivalent Actinides and Lanthanides by Triazinylpyridine N-Donor Ligands

“…The first synthesis of tridentate 2,6-bis(1,2,4-triazin-3-yl)pyridine ligands is described by Case . As shown in Scheme , the BTP ligands are synthesized by condensation reaction of pyridine-2,6-dicarbohydrazonamide with a 1,2-diketone. ,, In this manner, BTP compounds with various alkyl groups were prepared and tested for their complexation properties and their ability to extract and separate trivalent actinides from lanthanides (Figure left): R = H, , methyl, ,,− ethyl, ,,,,− n -propyl ,,,− ,,− ,− i -propyl, ,,− ,,,− n -butyl, ,, i -butyl, , pentyl, hexyl, heptyl, octyl, phenyl, , p -tolyl, and p - tert -butylphenyl . A few BTPs substituted in the 4-position of the pyridine ring were also synthesized (Appendix): MeO-BTP and Cl-BTP .…”