| 摘要 |
A method for preparing naphthalene dicarboxylic acid is provided to improve purity, color and economical efficiency and to allow naphthalene dicarboxylic acid to be applied directly to the polymerization of polyethylene naphthalate without additional purification. A method for preparing naphthalene dicarboxylic acid comprises the steps of oxidizing dimethyl naphthalene in the presence of a catalyst system and a solvent by using a system comprising a reactant manufacturing bath(1), an oxidation reactor(2), a crystallization bath(3), a solid/liquid separation device(4), a stock solution storage bath(5), an evaporator(6), an instant cooler(7) and a centrifuge(8); recirculating the some part of the discharged stock solution to the oxidation reactor through the reactant manufacturing bath after naphthalene dicarboxylic acid is recovered at a solid/liquid separation device; and transferring the some part of the stock solution to a centrifuge through the evaporator and the instant cooler to crystallize the organic impurities and to remove it, and transferring the remaining catalyst system to the reaction manufacturing bath.
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