| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for reducing attachment of an oxidation catalyst to a product in precise oxidation terephthalic acid process. SOLUTION: This method for producing an aromatic carboxylic acid comprises (1) a main liquid phase oxidation step for oxidizing an alkylbenzene with an oxygen- containing gas in the presence of a catalyst in a lower aliphatic acid carboxylic acid solvent in a first reaction area to provide slurry containing an aromatic carboxylic acid, (2) a step for additionally oxidizing the reaction mixture from the step 1 with an oxygen-containing gas without feed of the alkylbenzene in a second reaction area to provide crude slurry containing the aromatic carboxylic acid, (3) a step for additionally oxidizing crude slurry from the step 2 with oxygen-containing gas without feed of the alkylbenzene in a third reaction area having a temperature higher than that of the second reaction area to provide purified slurry containing the aromatic carboxylic acid, (4) a crystallization step for lowering purified slurry from the step 3 to proper temperature and pressure, (5) a separation step of the aromatic carboxylic acid for feeding the purified slurry from the step 4 onto a horizontal filtration face filter, (6) a step for washing the aromatic carboxylic acid from the step 5 with a lower carboxylic acid solvent and (7) a step for drying purified aromatic carboxylic acid from the step 6 to provide a product. |
