Extraction of Np(VII) by phenolic extractants from strongly basic solutions

Features of the extractive behavior of Np(VI) and -(VII) from basic solutions using aminomethyl derivatives of substituted phenols (KAAP) and oligomers of alkylphenol (DSBP) are found. The maximal extraction is observed under conditions where Np exists as hydroxo ions since the extraction occurs by loss of OH- from the hydroxo species and of H+ from the hydroxyl groups of the reagent. The shape of the 13C NMR spectra of the KAAP extracts confirms that NP is complexed by displacing H+ of the extractant hydroxyl groups by metal and is consistent with paramagnetic Np in the organic phase. Judging from the absorption data, it seems that the rate of Np(VII) reduction to Np(VI) increases with increasing extractant concentration and duration of extraction. It is found that Np(VI) is extracted by phenol extractants more slowly and with smaller distribution coefficients than Np(VII)