电动势法研究HAN与Fe^(3+)氧化还原反应动力学

Reaction Kinetic Between Hydroxylamine Nitrate and Fe^(3+) by Measuring Potential of Fe^(3+)/Fe^(2+)

采用电动势法研究了硝酸体系中硝酸羟胺(HAN)还原Fe3+离子的反应动力学,得到了动力学表观速率方程-dc(Fe3+)/dt=kc0.62(HAN)c-2.80(H+)c(Fe3+)c-0.85(Fe2+);当温度为50℃、离子强度I=1.0mol/L时,表观速率常数k=(2.9±0.1)×10-6(mol/L)3.02/s,反应表观活化能Ea=(125±3)kJ/mol。硝酸根的存在对反应起到抑制作用,离子强度的增大对反应有促进作用。

The kinetic study of the reaction between hydroxylamine nitrate（HAN） and Fe3＋ in nitric acid solution was performed by measuring the potential of Fe3＋/Fe2＋.The effects of the concentration of HAN,the concentration of nitric acid,ionic strength,temperature and the concentration of Fe3＋ on the reaction rate were also studied.The apparent rate equation may be expressed as follows：-dc（Fe3＋）/dt=kc0.62（HAN）c-2.80（H＋）c（Fe3＋）c-0.85（Fe2＋） The apparent rate constant is（2.9±0.1）×10-6（mol/L）3.02/s at 50 ℃ and I=1.0 mol/L and the apparent reaction activation energy is（125±3） kJ/mol.NO-3 can depress the reaction and increasing ionic strength can promote the reaction.