REACTION OF H2O2 WITH SUSPENSIONS OF NP(OH)(4) AND PU(OH)(4) IN ALKALI SOLUTION

In 0.5-16 M NaOH solution purged with Ar hydrogen peroxide oxidizes wi thin some minutes freshly formed Np(OH)(4) to Np(V), which reacts with excess H2O2 to form a colored complex passing into the solution. The oxidation rate decreases with increasing NaOH concentration. The incre ase of H2O2 concentration accelerates the reaction. The stability of t he complex depends on the H2O2 concentration and temperature. In 4 M N aOH freshly formed Pu(OH)(4) is appreciably oxidized by H2O2 Twenty mi nutes after mixing of the reagents the plutonium concentration in solu tion was found to be 1 x 10(-4) M. In 12 M NaOH the solution turns bro wn in 10 min after the mixing. The absorption spectrum of this solutio n is identical to that of the Pu(V) peroxide complex. The additives of copper, cobalt, and iron salts accelerate the Pu(IV) oxidation.