乙异羟肟酸对Fe(Ⅲ)与羟胺反应动力学的影响

Effects of Acethydroxamic Acid on Kinetic of Reaction Between Hydroxylamine and Fe(Ⅲ)

摘要: 采用分光光度法，对硝酸体系中羟胺（HAN）还原Fe(Ⅲ)的动力学进行了研究，得出了反应速率方程为-dc(Fe(Ⅲ))/dt=k•c^0.56(Fe(Ⅲ))•c^0.88(HAN)，表观速率常数k=-(4.08±0.15)×10^-4 (mol/L)^-0.44•s^-1；并研究了乙异羟肟酸（AHA）与Fe(Ⅲ)络合对该氧化还原反应的影响，结果显示，反应速率方程变为-dc(Fe(Ⅲ))/dt=-(2.83×10^-4-536c³(AHA))•c^0.76(Fe(Ⅲ))•c^0.60(HAN)，反应速率常数随AHA浓度增大而降低，且与AHA浓度的3次方成线性关系，Fe(Ⅲ)浓度对反应速率影响增大，而HAN浓度对反应速率影响减小。

Abstract: The kinetic of the reaction between hydroxylamine and Fe(Ⅲ) in nitric acid solution was studied by spectrophotometry. The apparent rate equation may be expressed as follows:
-dc(Fe(Ⅲ))/dt=k•c^0.56(Fe(Ⅲ))•c^0.88(HAN)
The apparent rate constant is =-(4.08±0.15)×10^-4 (mol/L)^-0.44•s^-1. The effects of acethydroxamic acid on the reaction were also studied. The apparent rate equation is converted into:
-dc(Fe(Ⅲ))/dt=-(2.83×10^-4-536c³(AHA))•c^0.76(Fe(Ⅲ))•c^0.60(HAN)
The apparent rate constant decreases with the increase of the concentration of AHA and is linearly related to the cubic of the concentration of AHA. The effect of the concentration of Fe(Ⅲ) on the apparent rate increases, while that of the concentration of HAN decreases.