is kept at 0 deg c to facilitate the reaction the tlc tracking is performed after being completely dropped the solution reacts for 1 hour and the complete reaction is detected by means of tlc a sodium bicarbonate saturated solution is added under the ice bath until the water phase is alkaline then the solution is separated an organic phase is added into a saturated sodium thiosulfate solution while in stirring until the organic phase becomes a colorless transparent solution then the solution is separated the organic phase is washed by utilizing a saturated saline solution dried by anhydrous sodium sulfate filtered and washed by dichloromethane the filtrate and the washing solution are mixed to obtain a mixture the rotary evaporation is performed on the mixture to remove the solvent to constant weight to obtain 215 g of white powdered solid and the content detected by hplc is 96 83 hnmr 400 hz cdcl3 u03b4 7 96 m 2h 7 38 m 2h 5 27 m 1h 4 36 m 1h 3 96 m 1h 2 56 s 3h synthesizing the compound 2 bromo 3 chloro 1 4 methylsulfonyl phenyl 1 acetone adding 160 g of 2 bromo 3 chloro 1 4 methylmercapto phenyl 1 acetone and 600 g of acetonitrile into a 2500 ml three opening bottle stirring to dissolve the raw material adding 5 g of catalyst na 2 wo 4 2h 2 o dropwise adding 375 g of 30 hydrogen peroxide when the hydrogen peroxide is dropped controlling the temperature in the reaction solution not to be higher than 60 deg c after the.