Method for producing purified ammonium salt of fluorinated bis-sulfonylimide

Abstract

Methods for preparing an ammonium salt and a lithium salt of a fluorinated bis-sulfonylimide by a practical and efficient method with a high yield with a small number of steps. Further, a high purity ammonium salt of a fluorinated bis-sulfonylimide useful for the method for producing a lithium salt is provided. A method for producing a purified particulate solid (II) of a salt represented by the formula (1), which comprises suspending a particulate solid (I) of a salt represented by the formula (1) in a solvent comprising an etheric oxygen atom-containing compound, and separating the solvent by filtration: [HNR 3 ] + [Q 1 -SO 2 —N—SO 2 -Q 2 ] −   (1) wherein each of R′ s which may be the same or different, is a hydrogen atom or a C 1-10 alkyl group, and each of Q 1 and Q 2 which are independent of each other, is a monovalent fluoroorganic group, or Q 1 and Q 2 together form a bivalent fluoroorganic group.

1 . An ammonium salt represented by the following formula (1), which has a purity as measured by NMR of 99 mol % or higher:
   [HNR 3 ] + [Q 1 -SO 2 —N—SO 2 -Q 2 ] −   (1)   wherein R′s which may be the same or different, is a hydrogen atom or a C 1-10  alkyl group, and each of Q 1  and Q 2 , which may be the same or different, is a monovalent fluoroorganic group, or Q 1  and Q 2  together form a bivalent fluoroorganic group.   
     
     
         2 . The ammonium salt according to  claim 1 , wherein R is a methyl group, an ethyl group, a n-propyl group, an isopropyl group or a n-butyl group. 
     
     
         3 . The ammonium salt according to  claim 1 , wherein [HNR 3 ] +  is ammonium, trimethylammonium, triethylammonium, tri-n-propylammonium, triisopropylammonium, tri-n-butylammonium, dimethylethylammonium, methyldiethylammonium, dimethyl-n-propylammonium, methyl-di-n-propylammonium, dimethylisopropylammonium, methyldiisopropylammonium, dimethyl-n-butylammonium, methyl-di-n-butylammonium, diethyl-n-propylammonium, ethyl-di-n-propylammonium, diethylisopropylammonium, ethyldiisopropylammonium, diethyl-n-butylammonium or ethyl-di-n-butylammonium. 
     
     
         4 . The ammonium salt according to  claim 1 , wherein [HNR 3 ] +  is ammonium (NH 4   + ) or triethylammonium. 
     
     
         5 . The ammonium salt according to  claim 1 , wherein each of Q 1  and Q 2  is a monovalent fluoroorganic group. 
     
     
         6 . The ammonium salt according to  claim 5 , wherein each of Q 1  and Q 2  is independently selected from a fluorinated alkyl group, a fluorinated alkenyl group and a fluorinated allyl group. 
     
     
         7 . The ammonium salt according to  claim 5 , wherein each of Q 1  and Q 2  is independently selected from perfluoroalkyl group, a perfluoroalkenyl group and a perfluoroallyl group. 
     
     
         8 . The ammonium salt according to  claim 1 , wherein Q 1  and Q 2  together form a bivalent fluoroorganic group. 
     
     
         9 . The ammonium salt according to  claim 8 , wherein Q 1  and Q 2  together form a perfluoroalkyl group having 1 or 2 carbon atoms, or they together form a C 1-3  perfluoroalkylene group. 
     
     
         10 . The ammonium salt according to  claim 1 , wherein [Q 1 -SO 2 —N—SO 2 -Q 2 ] is represented by one of the following formulae: 
       
         
           
           
               
               
           
         
       
     
     
         11 . The ammonium salt according to  claim 1 , wherein the NMR is  19 F-NMR. 
     
     
         12 . An ammonium salt represented by the following formula (1-1), which has a purity as measured by NMR of 99 mol % or higher: 
       
         
           
           
               
               
           
         
       
     
     
         13 . The ammonium salt according to  claim 12 , wherein the NMR is  19 F-NMR.