Preparation of 5-chlorosulfonylisophthaloyl chloride for membrane synthesized

5-chlorosulfonylisophthaloyl chloride(CSIC) was an important functional monomer for the synthesis of polyamide reverse osmosis and nanofiltration membrane.Phosphorus pentachloride(PCl5) was used as carbonyl chlorinating agent to prepare 5-chlorosulfonylisophthaloyl chloride(CSIC) from Sodium 3,5-dicarboxybenzenesulfonate,and the top yield of CSIC was 71.4%.Effects of reaction conditions such as the reaction temperature,reaction time and the response ratio on the product yield were discussed: at atmospheric pressure the reaction nearly completed after 12.5 hours while the temperature maintained at 170-180 ℃;If the mole ratio of PCl5 to Sodium 3,5-dicarboxybenzenesulfonate was less than 1∶1,few products could be obtained.When the ratio was between 1∶1 and 2.5∶1,the yield is enhanced by the ratio.As mole ratio is higher than 2.5∶1,the yield is hardly affected.