摘要
利用废弃聚酯在乙二醇介质中解聚,其解聚温度为160～200℃,催化剂醋酸锌用量一般为0.03％～0.1％,得到的中间产物为对苯二甲酸双羟乙酯单体(BHET)及少量齐聚物。BHET含量(在一定时间内)随解聚时间增加而增大,解聚温度为200℃时,解聚所需时间最短。分离除去乙二醇后的中间产物与过量甲醇发生酯交换反应,反应温度为58～70℃,催化剂氢氧化钠用量一般在0.05％～0.15％之间,得到的产物DMT含量为96％～98％。
The wasted polyester(PET) are depolymerized at 160～200℃ by using ethylene glycol. Normally, the quantity of zinc acetate used as catalyst is 0.03%～0.1%, obtained intermediates are bis(2-hydroxyethyl) terephthalate (BHET), and a small amoant of oligomers. Within a certain time, the longer the depolymerizing time, the more the content of BHET, when the temperature is at 200℃, the depolymierizing time is shortest. After removing the ethylene glycol, the intermediates react with excessive methanol at 58～70℃, normally, the quantity of sodium hydroxide used as catalyst is 0.05%～0.15%, and the content of DMT in the products is 96%～98%.
关键词
对苯二甲酸酯
DMT
PET
聚酯
解聚
depolymerization, intermediate
polyster(PET) wastes, dimethyl terephthalate(DMT), oligomer.
