羟基脲与HNO_2的反应动力学及对Pu(Ⅲ)的稳定性研究

Hydroxyurea Reaction With HNO_2 and Pu(Ⅲ) Stabilization

在HNO3溶液中,研究了羟基脲(HU)与HNO2反应的动力学。研究结果表明,反应对HU呈零级,速率方程可表示为:-dc(HNO2)/dt=k0c(HNO2)c1 1(HNO3)c0(HU),在t=10℃,c(HNO2)=5mmol/L时,k0=(0 18±0 01)L1 1·mol-1 1·s-1,反应活化能Ea≈63kJ/mol。在不同离子强度的NaNO3溶液中的研究表明,离子强度变化对反应速率影响不大。分光光度法和萃取法研究表明,过量的HU在HNO3溶液中可以很好地稳定Pu(Ⅲ)。

Reaction kinetics of hydroxyurea(HU) with HNO_2 in nitric acid solution is studied.The results show that the reaction rate follows the equation as:-d c (HNO_2)/d t = k_0c (HNO_2) c ^(1.1)(HNO_3)( c ~0(HU)),where k_0 =(0.18±0.01) L^(1.1)·mol^(-1.1)·s^(-1) at 10 ℃ and c (HNO_2)=5 mmol/L;the activation (energy) is deduced to be about 63 kJ/mol.The reaction appears zero order relative to HU.Kinetic study performed at various NaNO_3 solutions shows that salt ions have little effect on the reaction rate.Excess HU can stabilize Pu(Ⅲ) well in nitric solutions.