Thermodynamic Approach of Uranium(VI) Extraction by N,N-(2–ethylhexyl)Isobutyramide

The study of extraction of U(VI) from LiNO3 media by N,N-(2-ethylhexyl)isobutyramide (DEHiBA) in dodecane has been performed at 25.00 °C using isothermal titration microcalorimetry. The raw heat measured is a sum of contributions. To obtain the net extraction enthalpy variation, different heats have to be evaluated as the dilution of amide into dodecane phase which has been measured and subtracted. The microcalorimetric extraction results are then compared to data obtained by Van’t Hoff classical method. The extraction enthalpies obtained by both methods are similar. This first study allowed to define the experimental calorimetric conditions and will be followed by determination with other actinides and amides.