Hydrochloric Acid → Disodium

Participants

Reaction Steps

A 41.0 g portion of recrystallized 3-amino-5-hydroxy-2,7-naphthalenedisulfonic acid and 16.5 g of sodium acetate trihydrate are dissolved in 250 ml of distilled water, then 44.55 g of m-nitrobenzoyl chloride is added all at once along with 120 ml of 1 N sodium hydroxide and a small amount of diethyl ether. The resulting mixture is shaken for 5 minutes, another 120 ml of 1 N sodium hydroxide and a small amount of diethyl ether. The resulting mixture is shaken for 5 minutes, another 120 ml of 1 N sodium hydroxide is added and the mixture is shaken for 1/2 hour. The latter addition and shaking is repeated two more times. The resulting mixture is acidified to Congo Red indicator paper with concentrated hydrochloric acid and allowed to stand at 5° C. for 17 hours. The solution is filtered and the filtrate allowed to stand until a precipitate forms. The precipitate is stirred with about 400 ml of diethyl ether and collected to give 5-hydroxy-3-m-nitrobenzamido-2,7-naphthalenedisulfonic acid, disodium salt.

Provenance & Evidence