硝酸介质中单甲基肼与亚硝酸的反应动力学

Reaction Kinetics of Mono-methylhydrazine With Nitrous Acid in Nitric Acid Medium

摘要: 采用分光光度法研究硝酸介质中单甲基肼(MMH)与亚硝酸(HNO2)的反应。HNO2和MMH反应动力学速率方程为－dc(HNO2)/dt=kc(H+)c1.1(NO－3)c1.1(MMH)c(HNO2)。当t＝2.6 ℃、c(NO－3)＝0.50 mol/L时，反应速率常数k=(115±2) (mol/L)－3.2•s－1，反应活化能Ea=(37.8±0.1) kJ/mol。研究结果表明：在硝酸介质中，甲基肼与亚硝酸能快速反应；提高酸度、MMH浓度或硝酸根浓度均有利于亚硝酸的还原。

Abstract: The oxidation of mono-methylhydrazine (MMH) with nitrous acid in nitric acid medium was researched. The rate equation was determined as follows: －dc(HNO2)/dt=kc(H+)c1.1(NO－3)c1.1(MMH)c(HNO2). The k is (115±2) (mol/L)－3.2•s－1 and the corresponding activation energy Ea is (37.8±0.1) kJ/mol with the nitrate concentration of 0.50 mol/L at the temperature of 2.6 ℃. The result indicates that the oxidation of MMH with nitrous acid is fast. The increase in the acidity and the concentration of MMH or NO－3 can speed the reduction of nitrous acid.