高氯酸介质中单甲基肼与亚硝酸的反应动力学

用分光光度法研究了高氯酸介质中单甲基肼(MMH)与亚硝酸(HNO_2)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(HNO_2)/dt=kc(H~+)~(0.9)c(MMH)~(1.1)c(HNO_2).温度4.5 ℃, c_0(ClO_4~-)＝0.50 mol/L时,反应速率常数k＝(46.0±2.7) L~2/(mol~2·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.

Reaction Kinetics of Monomethylhydrazine With Nitrous Acid in Perchloric Acid Solution

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(HNO_2)/dt=kc(H~+)~(0.9)c(MMH)~(1.1)c(HNO_2), k is (46.0±2.7) L~2/(mol~2·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.