Ion-pair extraction of Am(III) and Eu(III) with oligo-pyridine ligand

The ion-pair extraction of Am(III) and Eu(III) using tris(2-pyridyl)carbinol (TPC) and tris(2-pyi-idyl)methoxymethane (TPM) was studied. The distribution ratio of Am(III) and Eu(III) was improved by the addition of TPC or TPM in the presence of picric acid (Hpic) as ion-pair reagent. In chloroform, 1,2-dichloroethane and nitrobenzene systems, the extraction of Am(III) and Eu(III) shows a moderate selectivity of Am(III) over Eu(III). In present study, the extraction equilibrium of Am(HI) and Eu(III) with TPC and Hpic was investigated in detail, in order to elucidate the extraction property of TPC. On the extraction of Am(III) and Eu(III) with TPC and Hpic into 1,2-dichloroethane, three molecules of TPC coordinate to respective trivalent ions (M3+). The extraction equilibrium was found as follows; M3+ + 3TPC + 3pic- -reversible arrow M(TPC)(3)(PiC)(3org). The extraction constants were 10(15.99) for Am(III) and 10(15.06) for Eu(III). (c) 2005 Elsevier B.V All rights reserved.