无酸体系中水合肼和尿素反应合成联二脲动力学

Kinetics of Biurea Synthesis from Hydrazine Hydrate and Urea in Acid-free Environment

为了考察无酸环境下水合肼和尿素合成联二脲的反应特性,在封闭式间歇反应釜中测定了不同温度下反应物水合肼浓度和终产物联二脲的质量随时间的变化,以了解水合肼和尿素的反应规律。计算了反应体系中游离氨浓度并测定了联二脲在水中的溶解度。结果表明:氨基脲合成和联二脲合成均为可逆反应,对所有组分均表现为一级反应。建立了氨基脲合成和联二脲合成的反应动力学模型,得到了不同温度下的反应平衡常数、反应速率常数和动力学模型参数。建立的动力学方程预测结果和实验数据吻合良好,可用于后续工程应用的优化设计。

To investigate the characteristics of biurea synthesis from hydrazine hydrate and urea in acid-free environment,the concentration of hydrazine hydrate and the mass of biurea were measured in a closed batch reactor at different temperatures.The concentration of free ammonia in the reaction system was calculated and the solubility of biurea in water was determined.The results showed that the reactions of semicarbazide synthesis and biurea synthesis were both reversible,and they were first-order reactions with respect to all components.The kinetic models for the reactions of semicarbazide synthesis and biurea synthesis were established.The equilibrium constants,reaction rate constants and kinetic model parameters at different temperatures were obtained.The predicted results were in good agreement with the experimental data,which can be used for the optimization design of subsequent engineering applications.