Carbamoylmethyl sulfoxides as novel extractants for actinides

A novel type of extractant for actinides called bis(dioctylcarbamoylmethyl) sulfoxide is described which neither contains phosphorus nor entails the addition of tributyl phosphate as phase modifier for extraction. This extractant, abbreviated as CMSO, has been found to be freely soluble in dodecane and to form no third phase even with concentrations of nitric acid as high as 10M. The distribution ratios for the extraction of Am(III), Pu(IV) and U(VI) at trace levels have been found to be 13, 220 ad 11, respectively, from 5M nitric acid using 0.2M CMSO in dodecane and those for backextraction have been found to be 2 x 10-4, 8 x 10-3 and 5 x 10-2 using 0.01M nitric acid, 0.1M oxalic acid and 0.35M sodium carbonate, respectively. Similar distribution ratios were obtained with the recycled extractant. Extraction was found to be very rapid. Eu(III) and Sr(II) were found to be moderately extracted with distribution ratios of 2 and 0.77, respectively, while the extraction of Cs(I) was negligible (KD 0.005). (author) 11 refs.; 1 fig.; 1 tab