ENVIRONMENTALLY FRIENDLY METHOD FOR PREPARING TEREPHTHALIC ACID EMPLOYING MULTISTEP OXIDATIONS

摘要

The present invention relates to a method for preparing a terephthalic acid via a paraxylene liquid phase oxidation, more particularly comprising a first oxidation reaction to obtain the terephthalic acid and a paratoluic acid in which the paraxylene is oxidized in a first oxidation reactor at 100~170°C in the presence of a water solvent and a first catalyst including a manganese salt and a cobalt salt, and a second oxidation reaction to obtain the terephthalic acid in which the unreacted paraxylene in the first oxidation reaction and a reaction resultant are oxidized in a second oxidation reactor at 150~220°C in the presence of a water solvent and a second catalyst including a manganese salt and a cobalt salt, characterized in that the concentration of paraxylene in the liquid of the first oxidation reactor is adjusted to 30~90 wt %.