| 摘要 |
PURPOSE: A method for preparing polyethylene terephthalate is provided, to prevent the deterioration of the heat resistance and the color of a resin due to the use of the terephthalic acid of a low purity. CONSTITUTION: The method comprises the steps of reacting terephthalic acid containing the terephthalic acid of a low purity with ethylene glycol to prepare bis-(β-oxyethyl)terephthalate by esterification using the acetate-based compound represented by the formula I and the base compound represented by the formula II; and polycondensation reacting the bis-(β -oxyethyl)terephthalate to obtain polyethylene terephthalate, wherein M is a monovalent or divalent metal; n is 1 or 2; m is 2 or 3; and R is an alkyl group of C1-C8. The terephthalic acid comprises only the terephthalic acid of a low purity or both the terephthalic acid of a low purity and the terephthalic acid of a high purity.
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