Method for producing high-purity terephthalic acid

A method for producing a high-purity terephthalic acid, the method comprising:

• (a) liquid-phase oxidizing a p-phenylene compound to obtain crude terephthalic acid crystals;
• (b) dissolving the crude terephthalic acid crystals in water and to obtain a mixture, and then subjecting the mixture to catalytic hydrogenation treatment obtain a reaction liquid;
• (c) depressurizing and cooling the reaction liquid after the catalytic hydrogenation treatment in stages with two or more stages of crystallization vessels, to crystallize terephthalic acid and obtain a terephthalic acid slurry containing crystallized terephthalic acid;
• (d) introducing the terephthalic acid slurry into an upper portion of a mother liquor replacement tower, bringing the crystallized terephthalic acid into contact with an upward flow of replacement water introduced from a tower bottom portion of the mother liquor replacement tower while making the crystallized terephthalic acid settle down in the tower, and withdrawing the crystallized terephthalic acid as a withdrawn slurry with the replacement water from a tower lower compartment;
• and
• (e) performing solid-liquid separation of the withdrawn slurry into water and separated terephthalic acid crystals, and drying the separated terephthalic acid crystals,
• wherein, when a throughput of the crude terephthalic acid crystals subjected to the catalytic hydrogenation treatment is Q [ton/hr], and a residence time in a first-stage crystallization vessel of the two or more stages of crystallization vessels is T1 [hr], and a cross-sectional area of the mother liquor replacement tower is A [m2], following conditions (1) to (3) are all satisfied:
• 0.07≤T1≤0.5 (1)
• 0.3≤A/Q≤0.8 (2)
• 0.035≤T1×A/Q≤0.25 (3).