Pusup((3)) oxidation in emulsion of 30% tbp-aqueous nitric acid solution containing hydrazine

Behaviour of plutonium (3) in aqueous solutions and two-phase intermingling systems with tributyl phosphate, containing nitric acid and hydrazine is studied. It is established that Pusup((3)) is practically stable in aqueous media in the range of [Pusup((3))]=2.1x10-3-4.2x10-2 mol/l at temperatures from 22 to 62 deg C. In emulsion of 30% TBP in n-dodecane-HNO3 aqueous solution, containing hydrazine (0.15 mol/l), plutonium (3) is oxidated to tetravalent state. Kinetic equation of the reaction has the following form: -d[Pusup((3))]sub(ag) dt=k[Pusup((3))]sup(1.7)x[HNOsub(3)]sub(org)sup(4.5), where k'=12.5+-1.0 lsup(5.2)/molsup(5.2)xmin at 32 deg C and ratio of organic and aqueous solution volumes n=1. It is found that the rate of Pusup((3)) oxidation increases with the temperature and value n increase. It is shown that nitrous acid (or nitrogen oxides) present in tributyl phosphate phase is the direct oxidant of Pusup((3))