Process for production of monosulfonium salts, cationic polymerization initiators, curable compositions, and products of curing

Abstract

A monosulfonium salt in which very little unreacted raw material remains, which has a purity of at least 96%, and which has one sulfonio group in its molecule is manufactured without a refining step. After (a) an aryl compound, (b) a sulfoxide compound, (c) a dehydrating agent, and (d) a BF 4 , PF 6 , AsF 6 , or SbF 6 salt of an alkali metal or an alkaline earth metal are introduced into a reaction system, (e) an inorganic acid is added, so that the aryl compound (a) and the sulfoxide compound (b) are subjected to dehydration condensation.

1 . A method manufacturing a monosulfonium salt represented by the general formula (1):  
       
         
           
           
               
               
           
         
         (in the formula, Ar denotes an optionally substituted aryl group; R 1  and R 2  denote each one of the same or different, optionally substituted heterocyclic groups or hydrocarbon groups; and X −  denotes BF 4   − , PF 6   − , AsF 6   − , or SbF 6   − ),  
         characterized in that (a) an aryl compound, (b) a sulfoxide compound, (c) a dehydrating agent, and (d) a BF 4 , PF 6 , AsF 6 , or SbF 6  salt of an alkali metal or an alkaline earth metal are introduced into a reaction system, followed by introduction of (e) an inorganic acid so that the aryl compound (a) and the sulfoxide compound (b) are subjected to dehydration condensation.  
       
     
     
         2 . The manufacturing method described in  claim 1 , wherein (e) the inorganic acid is sulfuric acid.  
     
     
         3 . The manufacturing method described in  claim 1 , wherein (f) an organic solvent having a boiling point not higher than 100° C. and (g) an organic solvent having a boiling point of 150° C. or higher are added to the reaction solution obtained by the dehydration condensation of the aryl compound (a) and the sulfoxide compound (b), followed by removal of the organic solvent (f) added to said reaction solution by distillation.  
     
     
         4 . A cationic polymerization initiator characterized by comprising the monosulfonium salt obtained by the manufacturing method described in  claim 1 .  
     
     
         5 . A curable composition characterized by comprising the cationic polymerization initiator described in  claim 4  and a cationically polymerizable compound.  
     
     
         6 . A cured material formed by curing of the curable composition described in  claim 5.