Medwick T, Abdou H M
J Pharm Sci. 1979 Mar;68(3):301-7. doi: 10.1002/jps.2600680312.
A comprehensive kinetic study was conducted of the reactions of m-nitrobenzhydrazide and some other hydrazines with acetic acid. The overall reaction rate for all of the compounds studied followed pseudo-first-order kinetics. The temperature dependence of the m-nitrobenzhydrazide degradation reaction was determined. The reaction rate dependence on the acetic acid concentration was found to be close to first order. High-pressure liquid chromatography was used extensively in identifying and measuring the appearance or disappearance rates of m-nitrobenzhydrazide degradation products in acetous solution. With m-nitrobenzhydrazide, the major degradation products were N,N'-bis(m-nitrobenzoyl)hydrazine, N-acetyl-N'-m-nitrobenzoylhydrazine, diacetylhydrazine, and hydrazine. The concentration profiles of these products in solution suggested a complex mechanism by which hydrazides react with acetic acid. All eight rate constants at 61 degrees in the suggested mechanism were calculated by an approximation method based on experimental data. The findings in the present study indicate that acetic acid is to be avoided as a solvent for hydrazine derivatives.
对间硝基苯甲酰肼及其他一些肼类与乙酸的反应进行了全面的动力学研究。所研究的所有化合物的总反应速率均遵循准一级动力学。测定了间硝基苯甲酰肼降解反应的温度依赖性。发现反应速率对乙酸浓度的依赖性接近一级。高压液相色谱法被广泛用于鉴定和测量间硝基苯甲酰肼降解产物在醋酸溶液中的生成或消失速率。对于间硝基苯甲酰肼，主要降解产物为N,N'-双（间硝基苯甲酰基）肼、N-乙酰基-N'-间硝基苯甲酰肼、二乙酰肼和肼。这些产物在溶液中的浓度分布表明酰肼与乙酸反应的机制较为复杂。通过基于实验数据的近似方法计算了所提出机制中61摄氏度下的所有八个速率常数。本研究的结果表明，应避免将乙酸用作肼衍生物的溶剂。
