聚酯工业生产中催化剂的作用

根据实验及过程特点分析讨论了催化剂在PTA与EG直缩法生产聚酯的酯化、预缩聚、终缩聚三个阶段中的作用，酯化段，由于端羧基中的H＋本身即为酯化反应催化剂，促进缩聚反应的锑系催化剂对酯化过程基本无影响；在传质影响很小的预缩聚段，同样Sb3＋浓度和同样反应条件下，Sb2O3和SbAc3可以得到相同的催化结果；Sb3＋浓度越高，编聚速率越快；终缩聚段，由于传质的影响，催化剂的作用随聚合度的上升渐渐被弱化。

Effect of catalyst on PET industrial process

Based on experiments and characteristic of process, effects of catalytst on PET industrial processare discussed. In esterification stage, H+ of end-carboxyl itself is the catalyst of the esterification reactions.The polycondensation reaction is catalyzed by compounds of antimony catalyst which doesn' t affect the es-terification reachons. In prepolycondensation stage, with the same concentration of Sb3+ and the same reac-tion condition, the catalyzing results of Sb2O3 and SbAc3 were same. The higher the conentration of antimo-ny ion is, the faster the rate of polycondensation reaction is. In final polycondensation stage, by influence ofmass-transfer, the catalyst has less effect on the reaction with the increasing of the degree of polymeriza-tion.