Process for dissolution of highly fluorinated ion-exchange polymers

Abstract

Highly fluorinated ion-exchange polymers achieve dissolution in aqueous tetrahydrofuran at lower pressures and temperatures than in other solvents, with few or no side products being formed.

1 . A process for making a liquid composition of highly fluorinated ion-exchange polymer comprising 
 a) contacting the polymer with aqueous tetrahydrofuran, and    b) heating said polymer in contact with aqueous tetrahydrofuran to form the liquid composition.    
     
     
         2 . The process of  claim 1  wherein said aqueous tetrahydrofuran is comprised of water and tetrahydrofuran in a ratio of about 10:90 to about 90:10 weight %.  
     
     
         3 . The process of  claim 1  wherein said aqueous tetrahydrofuran is comprised of water and tetrahydrofuran in a ratio of about 45:55 to about 55:45 weight %.  
     
     
         4 . The process of  claim 1  wherein said aqueous tetrahydrofuran is comprised of less than about 50 weight % tetrahydrofuran.  
     
     
         5 . The process of  claim 1  wherein the polymer comprises about 1 to about 15 weight % of the combined weight of polymer and water and tetrahydrofuran.  
     
     
         6 . The process of  claim 1  wherein said polymer in contact with aqueous tetrahydrofuran is heated to a temperature of about 150° C. to about 300° C.  
     
     
         7 . The process of  claim 1  wherein said polymer in contact with aqueous tetrahydrofuran is heated in a autoclave.  
     
     
         8 . The process of  claim 1  wherein said highly fluorinated ion-exchange polymer is in the acid form, sodium ion form or potassium ion form, or a combination thereof.  
     
     
         9 . The process of  claim 1  wherein said highly fluorinated ion-exchange polymer is in the acid form.  
     
     
         10 . The process of  claim 1  wherein said ion-exchange polymer is perfluorinated.  
     
     
         11 . The process of  claim 1  wherein said ion-exchange polymer has an ion-exchange ratio of about 3 to about 33.  
     
     
         12 . The process of  claim 1  wherein said ion-exchange polymer has an ion-exchange ratio of about 8 to about 23.  
     
     
         13 . The process of  claim 1  wherein said composition is substantially free of products from reactions of the solvent during preparation of said composition.  
     
     
         14 . A liquid composition consisting essentially of ion-exchange polymer in aqueous tetrahydrofuran, at least about 50% of the total number of halogen and hydrogen atoms in said ion-exchange polymer being fluorine atoms.  
     
     
         15 . The liquid composition of  claim 14  wherein the aqueous tetrahydrofuran is from about 10:90 weight % water:tetrahydrofuran to about 90:10 weight % water:tetrahydrofuran.  
     
     
         16 . The liquid composition of  claim 14  wherein the aqueous tetrahydrofuran is from about 45:55 weight % water:tetrahydrofuran to about 55:45 weight % water:tetrahydrofuran.  
     
     
         17 . The liquid composition of  claim 14  wherein said ion-exchange polymer is in the acid form.  
     
     
         18 . The liquid composition of  claim 14  wherein said ion-exchange polymer is about 1 to about 15 weight % of the combined weights of the polymer and aqueous tetrahydrofuran.  
     
     
         19 . The liquid composition of  claim 14  wherein said ion-exchange polymer is perfluorinated.  
     
     
         20 . The liquid composition of  claim 14  wherein said ion-exchange polymer has an ion-exchange ratio of about 3 to about 33.  
     
     
         21 . The liquid composition of  claim 14  wherein said ion-exchange polymer has an ion-exchange ratio of about 8 to about 23.  
     
     
         22 . The liquid composition of  claim 14  wherein said composition contains less than about 3 weight % organic materials other than said tetrahydrofuran and those associated with said ion exchange polymer.