The effect of oxidizing agents on the stability of bis (2,4,4-trimethylpentyl) dithiophosphinic acid (НR, Cyanex 301) and its extracts with Cu, Ni, Co, and Zn in decane and toluene was studied. It was shown that the stability of НR and extracts varies in the following series of oxidizing agents: HNO3> H2O2> J2. In a mixture of Cyanex 301 with trioctylamine, the oxidation of the extractant is much more effective than with Cyanex 301 alone. The degree of degradation of Cyanex 301 is higher than that of extracts, which indicates a higher stability of НR salts in comparison with the acid itself. The main oxidation products of Cyanex 301 and its extracts (NiR2 and ZnR2) with HNO3, H2O2 and J2 were determined.

The data obtained can be useful to researchers in studying the extraction of metals with Cyanex 301 in various systems.