Synthesis of Anthranilic acid

Dissolve 80 g of sodium hydroxide in 300 mL of cold water, pour the solution to RBF in an ice bath. Then start vigorous stirring and add very slowly 21 mL of bromine, when the solution becomes yellowish clear and has cooled down to 0°C, add 59 g of phthalimide and then add 55 g of sodium hydroxide dissolved in 200 mL of water. Then stir for 1 minute and remove from the ice bath, then heat the mixture to 70°C for 20 minutes and cool down in an ice bath. Then with vigorous stirring under an ice bath, add conc. hydrochloric acid until the solution becomes neutral. Then transfer the solution to a very big beaker and with vigorous stirring slowly add glacial acetic acid until no more bubbling occurs. Filter and wash with water, dry in an oven. Recrystallize in hot ethanol.



Al of the bromine has reacted with the NaBrO


After addition of the phthalimide the solution slurried



Agitation of the mixture


When heated all of the compounds dissolved


The solution was cooled down in an ice bath and slowly the solution was neutralized with HCl


The solution was transferred to a large beaker and glacial acid was added very slowly


When adding the acetic acid the solution foams a lot, stop adding when no bubbling occurs anymore after addition


Filter and wash with water twice


98-99% pure anthranilic acid

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