间歇TPA法制备PET过程中DEG生成规律及控制方法

FORMATION AND CONTROL OF DEC DURING THE PET PRODUCTION BY BATCH TPA PROCESS

我们在二升间歇装置中,对高纯度对苯二甲酸(TPA)和乙二醇(EG)直接酯化缩聚(简称TPA法)时的酯化温度、酯化压力、酯化时间及醚键抑止剂的添加量,作了一系列的试验。其结果表明:采用TPA法制备PET主要在酯化阶段生成副产物DEG,其量占总量80％。其次是缩聚阶段;提高酯化反应速度,宜用加压法来实现,一般反应压力4.0×10~5Pa、反应温度250℃;及时除去反应系统中多余的EG;添加适量的醚键抑止剂可有效地降低DEG的生成。

A series of experiments is carried out in a 2 liter reactor on the technological condition of direct esterfication polymerization of TPA and EG, in respect of temperature, time and pressure in. the esterfication as well as the amount of ether-link inhibitor. The result shows in the production of PET by TPA process the DEG ty-product which forms mainly in the esterfication stage accounts for the 80% of the total amount, the esterfication reaction can be speed up by the increasing pressure applied which is around 4×10 Pa in general with a temperature of 250℃. The formation of DEG can be reduced effectively by the remove of excess EG promptly in the reaction system and the addition of suitable amount of ether-link inhibitor.