Study On The Synthesis Of P-Aminobenzenesulfonamide

p-Aminobenzenesulfonamide is an important medicine and intermediate, used in the synthesis of sulphanilamide crystal for anti-inflammatory, and other sulfa drugs such as Sulfaguanidine, Sulfa methoxy-triazine, Sulfamethyldiazine. In this paper, p-aminobenzenesulfonamide were produced with acetyl anilide as raw material, via chloro-sulfonation, amination and hydrolysis process. On the basis of this preparation process, a comprehensive waste discharge less routings was obtained via studying the comprehensive utilization of three waste treatment of the production process.1. In the chlorosulfonated process of preparing p-aminobenzenesulfonamide with acetyl anilide, excess chlorosulfonic acid method was used, and the impact of reaction time, reaction temperature, the molar ratio of the raw material, the reaction of the additive, solvent on the yield was studied. In the decomposition process of chlorosulfonation, the addition way of decomposition water was studied. When the molar ratio of acetanilide and chlorosulfonic acid is 1: 4.5, carbon tetrachloride and sodium chloride was added, and the reaction temperature was kept 60 oC for 3h. The mixture of chlorosulfonated was treated by quadratic decomposition method, and the yield was 65.33%. We also studied the impact of P₂O₅ and SOCl₂ on aminobenzenesulfonamide product yield and purity. When 20 g P₂O₅ was added to the reaction chlorosulfonation, 60 oC for 3h, the hundred fold yield of aminobenzene sulfonamide reached 83.98%, 98.11% purity. When 80 g SOCl₂ was added to the reaction chlorosulfonation, 60 oC for 3h, the yield reached 80.18%, 85.55% purity.2. During the animation process,we studied the impact of the reaction time, reaction temperature on the yield of final product. When 20% aqueous ammonia was added, 50 oC for 3h, the yield reached a maximum.3. During the hydrolysis process, the impact of acid hydrolysis conditions, reaction temperature and reactant concentration on the yield of the p-aminobenzenesulfonamide were studied. After the hydrolysis reaction, solution pH value and crystallization temperature were studied. When 40% NaOH was added at 105 oC for 2h, the p H of hydrolysis solution was 6.2, and when the crystallization temperature was 15 oC, the yield reached 69%.4. The hydrogen chloride gas generated in the chloro-sulfonation process was absorbed into 30% hydrochloric acid and the hydrochloric acid could be sold as by-product to make profits; one part of the spent acid generated in the chloro-sulfonation process was used to adjust the pH of reaction mixture after the hydrolysis process, the other was used for the acidification process of dihydroxynaphthalene in our company; the 4-sulfamoylaniline solution was concentrated to increase the product yield, and the final 4-sulfamoylaniline mother liquor was used for the decomposition reaction of chloro-sulfonation products; most of the inorganic salts generated in the concentration process of 4-sulfamoylaniline mother liquid was sodium chloride, which could be used as frozen brine;the condensate water generated in the concentration of 4-sulfamoylaniline mother liquid was used to wash ASC. After the improvement of synthetic technology, the yield of 4-sulfamoylaniline was increased from 69%?for industry? to 72.5%?using excess chlorosulfonic acid?, the cost was decreased correspondingly and the less waste was discharged.