废PET饮料瓶的醇解反应动力学

Kinetics of Glycolysis of Waste PET Beverage Bottles

探讨了以废聚酯 ( polyethyleneterephthalate ,简称PET)瓶和丙二醇 ( propylenegly col,简称PG)为原料 ,以醋酸锌为催化剂的熔融醇解反应实验方法 ,并进行了反应动力学的初步研究 .通过对反应过程中羟值和自由醇含量的定时分析 ,得到 3种不同PET/PG质量比的动力学曲线 ,对该曲线的分析结果表明 :解聚度随丙二醇投料量的增大而增大 ;醇解时间随丙二醇投料量的增大而减少 ;从解聚度、醇解时间及成本综合考虑 ,PET与PG质量比以 50 .0∶50 .0为宜 .实验结果还表明 :解聚度为最大值时的自由醇含量实验值与解聚度为 1 0 0 %时的自由醇含量理论值相符 ,说明本实验方法适合于废PET醇解反应动力学研究 ,醇解产物的化学分析操作也满足精度要求 .

The experimental method and kinetics of the glycolysis of waste PET beverage bottles were studied. Waste PET and propylene glycol(PG) were used as raw materials, and zinc acetate acted as catalyst. During the reaction, samples were collected at regular intervals and stored for determination of hydroxyl values and contents of free glycol later. Three kinetic curves of different formulations were obtained. The results indicate that, glycolytic extent increases with the increasing of content of PG, glycolytic time decreases with the increasing of content of PG; taking consideration of glycolytic extent, glycolytic time and the cost, the mass ratio of PET to PG should be 50.0 to 50.0. Besides, the content of free glycol at the maximal glycolytic extent is agreement with its theoretical value. This result indicates that the experimental method is suitable for study of kinetics of glycolysis and can satisfy the requirement of precision.