Kinetics of reactions of Np and Pu ions with hydrazine derivatives. I. Reaction between Np(VI) and methylhydrazine

The kinetics of the reaction between Np(VI) and methylhydrazine obeys the equation -d(Np(VI))/dt = k (Np(VI))/(CH/sub 3/N/sub 2/H/sub 4//sup +/)/(H/sup +/), where k = 32.1 +/- 1.8 and 52.7 +/- 1.7 min/sup -5/ at 25/sup 0/C and ionic strength ..mu.. = 2 and the activation energy is 56.9 +/- 0.8 and 58.6 +/- 0.4 kJ/mole in HClO/sub 4/ HNO/sub 3/ solutions respectively. The reaction mechanism includes a slow stage of electron transition between the NpO/sub 2//sup 2 +/ ions and the CH/sub 3/N/sub 2/H/sub 3/ molecules. The methyldiazenium cations formed at this stage subsequently decompose or are oxidized by the NpO/sub 2//sup 2 +/ ions.