| abstract |
(57) [Summary] [PROBLEMS] To prevent a distillate containing a low-concentration, low-temperature solvent from refluxing from a distillation column to an oxidation reaction column in the event of an emergency shutdown of the device, and to facilitate restarting of the device. In addition, a method for producing an aromatic carboxylic acid capable of reducing the size of a distillation column is proposed. SOLUTION: In a reaction solvent containing an aliphatic carboxylic acid in an oxidation reactor 1, an alkyl aromatic compound is liquid-phase oxidized with an oxygen-containing gas in the presence of an oxidation catalyst to produce an aromatic carboxylic acid, and an oxidized exhaust gas is discharged. 1. Distillation is performed by introducing into the first distillation column 2, and the exhaust gas from the distillation column is introduced into the second distillation column 3 via the intercooler 4 or the side reboiler to perform distillation, The distillate of the second distillation column 3 is returned to the first distillation column 2 via the pump 5, but when the apparatus is stopped in an emergency, it is withdrawn from the line L5 so that the low-concentration, low-temperature reflux liquid is removed from the oxidation reactor. This prevents a return to 1 and facilitates restarting the device. |