288 results about "Acetanilide" patented technology

The invention relates to a synthetic method of p-aminobenzenesulfonamide, which is characterized by successively includes the following steps: (a) adding chlorosulfonic acid into a reaction kettle, controlling the temperature to be 40-50 DEG C, adding acetanilide, increasing the temperature to 55-60 DEG C and performing a reaction for 1-2 h to obtain a first mixture; (b) adding dichloroethane, increasing the temperature to 65-75 DEG C, dropwisely adding a catalyst and SOCl2, and continuously performing the reaction for 1-3 h; (c) controlling the temperature in the reaction kettle to be 15-20 DEG C, dropwisely adding the mixed liquid obtained in the step (b) into ammonia water being 22-25% in mass concentration, stirring the liquid for 0.5-1 h, increasing the temperature to 40-42 DEG C and continuously performing the reaction with stirring for 1-2 h, and filtering the liquid to obtain a crude product of the p-aminobenzenesulfonamide; and (d) adding the crude product in a hydrolysis kettle, adding a NaOH solution being 20-30% in mass concentration, heating the mixture to 90-95 DEG C to perform reflux hydrolysis for 2-3 h, adding an acid solution to regulate the pH value to 6.5-6.7, performing centrifugation, and drying a filter residue to obtain the p-aminobenzenesulfonamide. In the method, the addition quantities of the reactants are accurately controlled so that the use amount of the chlorosulfonic acid is reduced. The method is reduced in cost and is increased in yield and purity of the product.