| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a simple chemical recycling method for recovering DMT (dimethyl terephthalate) and an alkylene glycol by a continuous depolymerization reaction using a waste polyalkylene terephthalate and methanol. SOLUTION: This method for recovering dimethyl terephthalate comprises continuously charging a polyalkylene terephthalate into a melting tank in the presence of distillation residues and/or an alkylene glycol, melting and converting the charged polyalkylene terephthalate into low mol.wt. products, continuously extracting the obtained melted product, transferring the extracted melted product into a depolymerization reaction tank and subsequently subjecting the transferred product to a depolymerization reaction using methanol. Therein, the free alkylene glycol component in the melting tank is controlled to 0.15-1.25 mole equivalent ratio based on the terephthalic acid component in the distillation residues, and the temperature of the melted product in the melting tank is also controlled to a range of 220-280 deg.C.</p> |
