N-diethyloctadecanamide (DEODA) in toluene has been studied. The effects of concentration of both aqueous phase nitric acid and DEODA as well as temperature on extraction distribution have been considered. The structure of the extracted species has also been confirmed by the FT-IR spectra. Extraction constant Kex at low nitric acid concentration and the thermodynaxnic constants of the extraction reaction are obtained. There is no third phase formation under the experimental conditions
which shows that DEODA is one of promising extractants in nuclear fuel reprocessing.