| 摘要 |
A method of obtaining 4-amino-3-nitrobenzenesulfonic acid by means of acetanilide sulfonation, nitration of the obtained product, then deacetylation in a mixture of water and ice, and precipitation of the 4-amino-3-nitrobenzenesulfonic acid in the hydrochloric acid environment, characterized in that the solution obtained as a result of nitration of sulfonated acetanilide is introduced into the mixture of water and ice at a voluminal ratio between 1 : 0.5 and 1 : 3.4, preferably 1 : 1, and the obtained mixture is stirred until crystallization begins, and further it is cooled to about minus15 degrees C and filtered, preferably under lowered pressure. The precipitate is washed with a small amount of cooled concentrated hydrochloric acid, and further with diethyl ether, and dried in a temperature between 80 and 100 degrees C, preferably with ventilation, and further the precipitate is suspended in boiling water at a voluminal ratio between 1 : 1.4 and 1 : 5.0, preferably 1 : 1.6, and after cooling, the solution separated from the precipitate is acidified with concentrated hydrochloric acid at a preferable voluminal ratio 1 : 1, and after cooling the crystallized product is separated and dried according to the already known method, or the solution separated from the precipitate is saturated at a temperature close to 0 degree C with gaseous hydrogen chloride.
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