4-Chloro-2-nitrobenzoic acid CAS# 6280-88-2

Firstly, 100g of 4-chloro-2-nitrotoluene is placed in a 1000mL three-necked flask together with 20g of vanadium pentoxide. Take 740g of pre-prepared 75% sulfuric acid solution and add it to the three-necked flask. Install thermometer, reflux distributor, dropping funnel, condenser, stirrer, tail gas absorption device, and vacuum device. Heat the reaction solution to the desired temperature under the stirring condition: turn on the vacuum device to keep the reaction system at a slight negative pressure to facilitate the discharge of more exhaust gas. The reaction temperature and pressure were maintained under stirring, and 110mL of 65% concentrated nitric acid was added slowly dropwise to the reaction mixture in llh. During the dropwise addition of nitric acid, part of the raw material will be evaporated with water Chemicalbook in the form of azeotropes, the distillate obtained by condensation is stratified, the oil phase is returned to the reformer, and the water phase is discharged. After the reaction is completed, maintain the reaction conditions and continue to stir 1l1. The reaction solution is cooled to 100-120°C, 250mL of extractant is added, the system temperature is maintained, stirred for 30min and left to stand, the mixture is stratified, and the aqueous phase is returned to the flask as the next reaction mother liquor. The oil phase was cooled to room temperature and filtered, and the filter cake was dried under vacuum at 50°C to obtain crude 4-chloro-2-nitrobenzoic acid. The crude 4-chloro-2-nitrobenzoic acid was recrystallized with chlorobenzene and dried under vacuum at 50°C to obtain a product with a purity of more than 99%, which has the appearance of a white crystalline powder.

4-Chloro-2-nitrobenzoic acid is an important organic intermediate used in a variety of production fields such as pesticides, pharmaceuticals, and dyestuffs.