高氯酸介质中单甲基肼与亚硝酸的反应动力学

Reaction Kinetics of Monomethylhydrazine With Nitrous Acid in Perchloric Acid Solution

摘要: 用分光光度法研究了高氯酸介质中单甲基肼(MMH)与亚硝酸(HNO₂)的反应，建立了单甲基肼与亚硝酸的反应速率方程式。高氯酸介质中HNO2和MMH反应的速率方程如下：-dc (HNO₂)/dt=kc (H⁺)^0.9c (MMH) ^1.1c (HNO₂)。
温度4.5 ℃，c₀(ClO^-₄)＝0.50 mol/L时，反应速率常数k＝(46.0±2.7) L²/(mol²•s)，该反应的活化能 E_a=(42.4± 0.1) kJ/mol。以上研究结果表明，在高氯酸介质中，单甲基肼与亚硝酸能很快反应，提高酸度、增大单甲基肼浓度均有利于亚硝酸的还原。

Abstract: The oxidation of monomethylhydrazine(MMH) by nitrous acid was researched in perchloric acid solution with spectrophotometry. The rate equation has been determined as follows: ：-dc (HNO₂)/dt=kc (H⁺)^0.9c (MMH) ^1.1c (HNO₂)。k is (46.0±2.7) L²/(mol²•s) with the initial perchlorate concentration of 0.50 mol/L at the temperature of 4.5 ℃. The corresponding activation energy of the reaction is (42.4±0.1) kJ/mol. The results indicate that oxidation of mono-methylhydrazine(MMH) by nitrous acid is fast. The higher concentration of MMH can accelerate the reduction process of nitrous acid. Higher acidity can also speed up the reduction of nitrous acid.