Carbamoylmethylphosphoryl extractants

Three classes of carbamoylmethylphosphoryl extractants were studied for their ability to extract selected tri-, tetra-, and hexavalent actinides from nitric acid. The three extractants are dihexyl-N,N-diethylcarbamoylmethylphosphonate (DHDECMP), hexyl hexyl-N,N-diethylcarbamoylmethylphosphinate (HHDECMP), and octyl(phenyl)-N,N-diisobutylcarbamoylmethylphos-phine oxide 0< >D[IB]CMP0. The above three extrac-trants were compared on the basis of nitric acid and extractant dependencies for Am(III), solubility of complexes on loading with Nd(III) and U(VI), and selectivity of actinide(III) over fission products. 

We have studied the extractant behavior of a series of compounds containing the carbamoylmethylphosphoryl (CMP) moiety in which the basicity of the phosphoryl group and the steric bulk of the substituent group are varied (10,LL). These studies have led to the development of extractants which have combinations of substituent groups that impart to the resultant molecule improved ability to extract Am(III) from nitric acid and to withstand hydrolytic degradation. At the same time good selectivity of actinides over most fission products and favorable solubility properties on actinide loading are maintained (11). 

Distribution ratio of Am(III) versus aqueous nitric acid cone, for carbamoylmethylphosphoryl type extractants, extractant cone. = 0.5 M. 

TABLE III. Equations and Thermodynamic Parameters for the Extraction of Am(III) from Nitrate Media by Carbamoylmethylphosphoryl Derivatives... 

FPY and FQY—See Fluorescence photon and quantum yield Free energy of extraction of Am(III) by carbamoylmethylphosphoryl... 

Uranium(VI) and plutonium(IV) are separated from each other and from fission products by TBP, although phosphonates have better distribution coefficients than phosphates for Th and Carbamoylmethylphosphoryl (CMP) extractants are... 

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