Studies on the Parallel Synthesis and Evaluation of New Heterocyclic Extractants for the Partitioning of Minor Actinides

Abstract

Multiple parallel synthesis and evaluation have been combined in order to identify new nitrogen heterocycles for the partitioning of minor actinides(III) such as americium(III) from lanthanides such as europium(III). An array of triazine‐containing molecules was made using multiple parallel syntheses from diketones and amide hydrazides. An excess of each of the resulting purified reagents was dissolved in 1,1,2,2‐tetrachloroethane containing 2‐bromodecanoic acid, and equilibrated with an aqueous solution containing the radiotracers ¹⁵²Eu and ²⁴¹Am in nitric acid ([Eu] + [Am] < 400 nanomol dm⁻³). Gamma counting of the organic and aqueous phases led to the identification of several new reagents for the selective extraction of americium(III). In particular, 6‐(2‐pyridyl)‐2‐(5,6‐dialkyl‐1,2,4‐triazaphenyl)pyridines were found to be effective reagents for the separation of americium(III) from europium(III), (SF_Am/Eu was ca. 30 in [HNO₃] = 0.013 mol/L).

Keywords:

• Parallel synthesis
• Parallel analysis
• Partitioning
• Minor actinides
• Nitrogen heterocycles
• 1,2,4‐Triazines
• Americium(III)
• Europium(III)

Acknowledgment

We thank the Nuclear Fission Safety Program of the European Union for support under the PARTNEW contract (F1KW‐CT‐2000‐00087).