| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing bis(2-hydroxyethyl)terephthalate from a polyester, by which the bis(2-hydroxyethyl)terephthalate having a high quality and a low acid value can stably be produced from the polyester containing polyethylene terephthalate as a main component and having an average water content of 0.5 to 3.0 wt.%.SOLUTION: The method for producing the bis(2-hydroxyethyl)terephthalate from the polyester containing polyethylene terephthalate as a main component and having an average water content of 0.5 to 3.0 wt.% is characterized by sequentially comprising the following stepes (a) to (b): the step (a): a step of depolymerizing the polyester with ethylene glycol at a temperature of 170 to 280°C; and the step (b): a step of distilling off the ethylene glycol from the depolymerization reaction product obtained in the step (a) at pressure of 20.0 to 60.0 kPa, until a difference between the weight of the ethylene glycol added in the step (a) and the weight of the ethylene glycol distilled off gives a weight ratio of 0.3 to 2.0 to the polyester added in the step (a), wherein the amount of the ethylene glycol distilled off in the step (b) is ≥5.0 wt.% on the basis of the depolymerization product obtained in the step (a). |
