Solubility of diaryl[dialkylcarbamoylmethyl]phosphind oxides in nitric acid solutions

Bidentate reagents, diaryl[dialkylcarbamoylmethyl]phosphine oxides (CMPOs), are promising as efficient extractants for recovery of actinides from wastes of radiochemical industry. A method for determining solubility of neutral bidentate organophosphorus compounds (NBOPCs), in particular diaryl[dialkylcarbamoylmethyl]phosphine oxides (CMPOs), in aqueous solutions of acids has been proposed. The method is based on the considerable increase in extraction of some elements-transplutonium (TPE), rare-earth (RE), iron(III), uranium(VI), etc.-from acid solution upon addition of small amounts of perchloric acid. The concentration of CMPO in an aqueous acid solution is determined by the following procedure: aliquots of HClO4 and any of the above radioactive isotopes were added to CMPO solution in nitric (or other) acid, the isotope was extracted with pure solvent as CMPO complex, and then the concentration was indirectly determined from the distribution coefficient using log Del = f ([R]) calibrating curve. The curve was plotted from the results of extraction of the isotope from the mixture of perchloric acid and nitric acid in which the concentration of the reagent was determined. The solubilities of three phenyl-substituted at the phosphorus atoms CMPOs with butyl, octyl, and isoamyl substituents at the nitrogen atom were measured in 3 M nitric acid