Hot-atom Chemistry of Cobalt-60 Atoms in Neutron Irradiated Organic Solutions of Tris(acetylacetonato)cobalt(III)

Thermal neutron irradiation has been carried out on the solutions of tris(acetylacetonato) cobalt(III) in benzene, ethanol, acetone and acetic acid containing various additives such as metallic salts and mineral acids. The 60Co retention in the irradiated solutions has been found to decrease sharply with the increase in the concentration of various metallic salts. This indicates that the thermal diffusive reactions which contribute greatly to the apparent retention in the irradiated solutions can be suppressed by the addition of adequate metallic salts as scavengers. Salts of the metals which can form more stable complexes with acetylacetone (i.e., Fe(III), Cu(II), Al(III), etc.) work as more effective scavengers in these systems. The upper limit for the primary retention of tris(acetylacetonato)cobalt(III) in the benzene solutions has been estimated as 0.00±0.02%. The use of adequate scavengers appears to be a useful technique to determine the primary retention in the irradiated solution systems. The 60Co retention of the solid complex irradiated at dry ice temperature was 1.4–1.5% irrespective of the organic solvents used for dissolution if they contain ferric chloride, while it increased to 2.0% in the absence of the scavenger.