二甲基羟胺还原Np(Ⅵ)的反应动力学

李小该; 何辉; 叶国安; 唐洪彬; 蒋德祥; 肖松涛

二甲基羟胺还原Np(Ⅵ)的反应动力学

中国原子能科学研究院放射化学研究所,北京102413

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- 收稿日期: 1899-12-31
- 修回日期: 1899-12-31
- 刊出日期: 2010-10-19

Reaction Kinetics Between N, N-Dimethylhydroxylamine and Neptunium(Ⅵ)

China Institute of Atomic Energy, P. O. Box 275(26), Beijing 102413, China

摘要

摘要: 用分光光度法研究了HNO₃介质中二甲基羟胺(DMHAN)还原Np(Ⅵ)的动力学。通过考察还原剂浓度和酸度等条件对Np(Ⅵ)动力学过程的影响，确定了反应的动力学速率方程为-dc(Np(Ⅵ))/dt=kc(Np(Ⅵ))c(DMHAN)/c^0.6(H⁺)，在温度θ＝25℃、离子强度I＝4.0 mol/kg时，速率常数k＝289.8(mol/L)-0.4/min。研究了离子强度、c(U(Ⅵ))和温度等因素对反应的影响。结果表明，离子强度和c(U(Ⅵ))对反应速率无显著影响，25℃时反应活化能为53.3kJ/mol；随着温度的升高，反应速率加快。并在此基础上推测了可能的反应机理。
- 二甲基羟胺 /
- Np(Ⅵ) /
- 反应动力学 /
- 反应机理
Abstract: The reaction kinetics between dimethylhydroxylamine (DMHAN) and Np(Ⅵ) in nitric acid media was studied by spectrophotometry. By investigating the influence of DMHAN concentration and acidity on the reaction, the reaction rate equation is obtained: -dc(Np(Ⅵ))/dt=kc(Np(Ⅵ))c(DMHAN)/c^0.6(H⁺), and the rate constant is 289.8(mol/L)-0.4/min at 25℃ and I=4.0mol/kg. The effects of ionic strength, c(U(Ⅵ)), and temperature were also investigated. The results show that the ionic strength and c(U(Ⅵ)) have no obvious effects on the reaction. The reaction activation energy was found to be 53.3 kJ/mol(25℃) by plotting the reaction rate constant against the reciprocal of reaction temperature. The negative activation energy implies that rising temperature will accelerate the reaction. Based on the above results, the reaction mechanism was explored.
- dimethylhydroxylamine /
- Np(Ⅵ) /
- kinetics /
- mechanism of redox reaction

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参考文献(12)

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二甲基羟胺还原Np(Ⅵ)的反应动力学

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出版历程

Reaction Kinetics Between N, N-Dimethylhydroxylamine and Neptunium(Ⅵ)

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