Abstract:

Ammoniation of adipic acid is an important method for the production of adiponitrile in industry. The neutralization reaction step is largely affected by the gas-liquid phase mass transfer. The neutralization reaction macrokinetic experiments were conducted in a 1 L semi-continuous stirred reactor. The variation of adipic acid concentration with reaction time was investigated from 210 to 260℃ with 0.2% (mass) phosphoric acid, 600 L·h^-1 ammonia and 1800 r·min^-1 stirring speed. When the concentration of adipic acid was higher than or equal to 0.1 mol·L^-1 at 250℃, the neutralization reaction was controlled by mass transfer and it was first-order with respect to adipic acid with activation energy of 42.9 kJ·mol^-1. When the concentration of adipic acid in the reactor was lower than 0.1 mol·L^-1 at 250℃, the reaction was controlled by reaction and it was second-order under reaction control with activation energy of 52.7 kJ·mol^-1. The calculation values and experimental results were matched well, and the intrinsic reaction kinetic order with respect to adipic acid was two according to the theoretical model. Besides, at 260℃, 0.2% (mass) phosphoric acid, 1800 r·min^-1 stirring speed and the same total pressure (slightly greater than the atmospheric pressure), the variation of adipic acid concentration with reaction time was investigated at a volume flow rate of ammonia between 200 to 600 L·h^-1. The results uncovered that the intrinsic reaction kinetic order with respect to ammonia was one.

Key words: adipic acid, ammonia, adiponitrile, reaction kinetics, multiphase reaction, mass transfer

摘要：

己二酸氨化法是工业上生产己二腈的重要方法之一,其中和反应步骤受气液相传质影响很大。采用体积为1 L的半间歇式反应釜,对己二酸中和反应的宏观动力学进行了研究。在磷酸质量分数为0.2%、搅拌速率为1800 r·min^-1、氨气流量为600 L·h^-1的条件下,实验考察了210～260℃范围内温度对己二酸浓度随时间变化的影响。由实验数据拟合结果表明:在250℃己二酸浓度大于0.1 mol·L^-1时为传质控制阶段,中和反应对于己二酸为一级,反应活化能为42.9 kJ·mol^-1;在250℃己二酸浓度小于0.1 mol·L^-1时为反应控制阶段,中和反应对于己二酸为二级,反应活化能为52.7 kJ·mol^-1。模型计算值与实验值相吻合,并结合理论模型得出对己二酸的本征反应级数为二级。保持总压(略大于常压)、温度260℃、搅拌速率1800 r·min^-1和磷酸质量分数0.2%保持不变,在氨气流量为200～600 L·h^-1的范围内考察了氨气分压对己二酸浓度随时间变化的影响,动力学拟合结果表明对氨气分压的本征反应级数为一级。

关键词: 己二酸, 氨气, 己二腈, 反应动力学, 气液相反应, 传质