| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for purifying a crude bishydroxyalkyl terephthalate(BHET) or the like, which can be applied to a chemical recycle system for PET or the like in improved efficiency without generating wastes by recycling a concentration product generated on the filtration treatment of the crude BHET without disposing of the concentration product. SOLUTION: This method for purifying a crude bishydroxyalkyl terephthalate comprising a depolymerization process for depolymerizing a polyalkylene terephthalate to produce the crude bishydroxyalkyl terephthalate and a purification process for filtering the obtained crude bishydroxyalkyl terephthalate and then purifying the filtered product, characterized by returning the concentration product filtered off by the filtration in the purification process to the depolymerization process.
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