Refined ethylene sulfite

Abstract

Refined ethylene sulfite exhibits excellent storage stability when used as a constituent of an electrolyte. Ethylene sulfite is formed by a step of reacting ethylene glycol and thionyl chloride to producing raw ethylene sulfite, a rectifying step for rectifying the raw ethylene sulfite, and a refining process for refining the raw ethylene sulfite or the rectified ethylene sulfite conducted before or after the rectifying step. The refining process is at least one process selected from the group consisting of a washing process, a dehydration process by total reflux distillation, a second rectifying process, and an absorbing process. Refined ethylene sulfite contains chloroethanol in an amount of not more than 1000 ppm.

1 . Ethylene sulfite produced by reacting ethylene glycol with thionyl chloride, 
 said ethylene sulfite containing chloroethanol in an amount of not more than 1000 ppm.    
     
     
         2 . Ethylene sulfite as set forth in  claim 1 , wherein said ethylene sulfite contains ethylene glycol in an amount of not more than 2000 ppm.  
     
     
         3 . Ethylene sulfite as set forth in  claim 1 , wherein said ethylene sulfite is obtained by a method of reacting ethylene glycol with thionyl chloride by a process including a rectification A, and providing at least one process which is another purification selected from the group consisting of washing with basic water, dehydration by refluxing, distillation (rectification B), and absorption before or after the rectification A.  
     
     
         4 . Ethylene sulfite as set forth in  claim 3 , wherein said method further comprises a simple distillation process of said raw ethylene sulfite or rectified ethylene sulfite which is conducted before said refining process.  
     
     
         5 . Ethylene sulfite as set forth in  claim 3 , wherein said absorbing process employs at least one absorbent selected from the group consisting of complex metal oxide, activated carbon and metal oxide.