9-氨基壬酸缩聚反应的动力学研究

9-氨基壬酸在恒沸的惰性介质中进行缩聚反应,生成的水,立即被介质蒸汽带走,用此法,缩聚反应极快.在十五分钟内,反应程度p,即已达到95％以上,三小时后,P可达99％以上,分子量M_n可达40000,这些都是前人没有做到的。 由于P可达99％以上,此法有可能研究缩聚反应的全过程。发现9-氨基壬酸的缩聚,从开始到p=99％,遵循二级反应。此后由于体系过分粘稠,反应速度随分子量增高即端基减少而变慢,反应转变为三级。

KINETIC STUDY ON THE POLYCONDENSATION OF 9- AMINO-PELARGONIC ACID

9-Amino-pelargonic acid was polycondensed in boiling inert paraffin hydrocarbon medium. The water formed during the reaction was immediately carried away by the vapor of the medium. By using this method. the polycondensation, ran very rapidly, and the extent of reaction p, reached more than 95%, within 15 min, and after three hours heating, p surpassed 99%. The average molecular weight became over 40,000. These results have never been achieved by other authors reported in literatures.Because p can be pushed to over 99%, it is possible to study the complete course of this polycondensation reaction It was found that the reaction followed a second order kinetics from the begining up to p=99%, beyond which the system became so viscous that a viscosity factor should be considered. Since the increase of viscosity will decrease the reaction rate, and the increase of molecular weight, i.e. a decrease of the concentration of the end group. will increase the viscosity, it follows that the decrease of the concentration of the end group will decrease the reaction rate, such that, the reaction changes into a third order kinetics as the extent of reaction goes over 99%.