Specific features of decomposition of hydroxamic acids in two-phase nitric acid systems with alcohols and TBP, as applied to 99Mo stripping

Abstract

Hydrolysis is the prevalent mechanism of decomposition of benzo- and caprinohydroxamic acids (HAs) in nitric and perchloric acid solutions and in the equilibrium organic phase based on heptanol, decanol, and 30% TBP in С13 paraffin diluent. In the nitric acid system with alcohols, HAs undergo autocatalytic oxidation at temperatures raised over 50°С. In the case of BHA, the process occurs in both phases taken separately and on their mixing. In the case of caprinohydroxamic acid poorly soluble in HNO₃ solutions, the autocatalytic process occurs only at 70–80°С on mixing the phases; it tends to fade as the phase ratio n = О/A is increased from 1 to 10. This trend determines the conditions for Mo stripping in this system. In the practice of the ⁹⁹Mo production, the stripping efficiency can be increased by repeated contact with the addition of non-salt complexing agents (H₂O₂, H₂C₂O₄, CH₃CONHOH) into the system.