Preparation method of dibenzenesulfonimide

Preparation of bis Benzenesulfonimide, comprising the steps of: a motor equipped with a stirrer, thermometer, reflux condenser, a reaction vessel, into sodium hydroxide and water, sodium hydroxide was completely dissolved was warmed to 50 ~ 57 ℃, was added benzenesulfonamide temperature was controlled at 53 ~ 57 ℃, benzenesulfonamide until completely dissolved, dropwise addition of benzenesulfonyl chloride dropwise for 30 minutes, additional sodium hydroxide solution, the PH value is maintained at 8 to 9 between after incubation the reaction was added dropwise benzenesulfonyl chloride in 2 to 4 hours, then heated to 100-105 deg.] C, refluxed for one hour, cooled to 26 ~ 30 ℃, adjusting the PH value of 4.0 to 7.5 with hydrochloric acid, centrifuges mixing the solid-liquid separation. The present invention makes use of a base is added to precipitate the sodium salt of BBI directly from the filtrate, and benzenesulfonamide better solubility of sodium salt does not precipitate in lye with BBI, so the high purity of the resulting product, good solubility.