| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for efficiently producing a high-purity aliphatic dicarboxylic acid or aromatic carboxylic acid. SOLUTION: A carboxylic acid is efficiently produced through a process (reaction process 1) for bringing a substrate (e.g. cyclohexane or paraxylene) into contact with oxygen in the presence of an imide compound (e.g. N- hydroxyphthalimide or N-acetoxyphthalimide), processes (crystallization process 2, filtration and washing process 3) for separating a crystallization component containing a carboxylic acid (e.g. adipic acid or terephthalic acid) and a noncrystalline component containing a catalyst and/or a by-product from the reaction mixture and processes (crystallization process 5, filtration and washing process 6 and drying process 7) for separating and purifying the carboxylic acid (e.g. adipic acid or terephthalic acid) from the crystallization component. Optionally, the reaction mixture from a reactor 1 may be fed to a concentration process. |
