【摘要】 报道了用分光光度法研究硝酸体系中偏二甲基肼还原Ｎｐ（Ⅵ）的动力学。研究了偏二甲基肼浓度、酸度、温度、离子强度、ＵＯ２２＋浓度等因素对反应速率的影响，求出了反应的动力学方程。实验结果表明：偏二甲基肼还原Ｎｐ（Ⅵ）—→Ｎｐ（Ⅴ）的速度较快，但不能进一步还原Ｎｐ（Ⅴ）—→Ｎｐ（Ⅳ），提高偏二甲基肼浓度、降低酸度、升高温度均有利于加快反应速率。离子强度和ＵＯ２２＋浓度对反应速率的影响很小更多还原

【Abstract】 The kinetic study of neptunium reduction with 1,1 dimethylhydrazine in nitric acid system with spectrophotometry has been performed.The effects,such as 1,1 dimethylhydrazine concentration,acidity,temperature,ionic strength and UO 2 2+ are investigated.The results show that Np(Ⅵ) can be rapidly reduced to Np(Ⅴ) by 1,1 dimethylhydrazine and no further reduction of Np(Ⅴ) to Np(Ⅳ) is observed under usual conditions.The reaction rate can be accelerated by increasing 1,1 dimethylhydrazin concentration and temperature,and decreasing acidity.The apparent activation energy ( E a) of this reduction is 47.2 kJ/mol.The influences of UO 2 2+ and the ionic strength of solution on reaction rate are negligible.The reaction rate equation can be expressed as follows:- d c Np (Ⅵ) d t=kc Np(Ⅵ) c (CH 3) 2NNH 2 c 0 9 HNO 3 更多还原