N-(Isoxazol-5-yl)sulphanilamide with CAS 7758-79-4

Industrial production methods include disodium hydrogen phosphate neutralization method and soda ash neutralization method.

1. Disodium hydrogen phosphate and neutralization water of twelve disodium hydrogen phosphate by the ratio of 3:2 add water to dissolve, filtered to remove and add filtrate to neutralizer and neutralization reaction in phosphate mix slowly, pH control in 4.2 ~ 4.6, the reaction solution by evaporating to form crystal film, the cooling crystallization, centrifugal separation, two water sodium dihydrogen phosphate. After drying at 100℃, anhydrous sodium dihydrogen phosphate was prepared. The mother liquor can be returned for dissolving disodium hydrogen phosphate.
2. Soda ash neutralization method: the extracted phosphoric acid is added into the neutralization reactor, and the soda ash solution is slowly added into the neutralization reaction under stirring to generate sodium dihydrogen phosphate, which is filtered, evaporated and concentrated, cooled to 60 ~ 70℃ to precipitate crystallization, and separated by centrifugation to obtain sodium dihydrogen phosphate dihydrate. Anhydrous sodium dihydrogen phosphate was prepared by air drying.