| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for obtaining high-quality bis-β-hydroxyethyl terephthalate from crude bis-β-hydroxyethyl terephthalate through evaporation or distillation. SOLUTION: This method for purifying crude bis-β-hydroxyethyl terephthalate comprises the following steps: a mixture containing the crude bis-β-hydroxyethyl terephthalate <=50 ppm in the total content of (i) cations including Na, Mg, Ca, Fe, Co, Zn, Ti, Sn, Sb, Ge and P and (ii) anions including halogens, NO2, NO3, PO4 and SO4 and >10 wt.% in ethylene glycol content is subjected to initial evaporation or distillation to distill off low-boiling compound(s) therein together with the ethylene glycol, and the resultant evaporation or distillation residues are then subjected to evaporation or distillation under reduced pressures.
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