Solvent extraction of 99Tc with acetylacetone and thiourea - formation mechanism of Tc(dmpt)3

Solvent extraction behaviour of technetium using hexakis(thiourea)technetium(III) ([Tc(tu)6]3+) and acetylacetone was investigated under various conditions. Although tris-(acetylacetonato)technetium(III) was not extracted by the direct substitution reaction of [Tc(tu)6]3+ with acetylacetone in the presence of a large excess of thiourea, technetium could be extracted with 4,6-dimethylpyrimidine-2(1H)-thione (Hdmpt) which was formed by the reaction of acetylacetone and thiourea. This feature was further confirmed by the extraction of Tc(dmpt)3 from [Tc(tu)6]3+ with Hdmpt. Mechanisms for the formation reaction of Hdmpt from acetylacetone and thiourea and extraction of Tc(dmpt)3 was established. (orig.)