Method for fluorodecarboxylation

Abstract

The present invention is directed to a method for replacing a carboxylic acid group with a fluorine .[.group.]. in a halogenated aliphatic carboxylic acid compound having the formula, R-COOH, to prepare a fluorinated product having the formula, R-F, wherein R is a halogenated aliphatic group including straight- and branched-chain aliphatic groups selected from the group consisting of halogenated aliphatic and .Iadd.halogenated .Iaddend.alkoxy-substituted .[.halogenated.]. aliphatic groups, wherein the method comprises the step of (a) reacting the halogenated aliphatic carboxylic acid compound with bromine trifluoride, and (b) recovering the fluorinated product.

We claim: 
     
       1. A method for replacing a carboxylic acid group with a fluorine .[.group.]. in a halogenated aliphatic carboxylic acid compound having the formula, R-COOH, to prepare a fluorinated product having the formula, R-F, wherein R is a halogenated aliphatic group including straight- and branched-chain aliphatic groups selected from the group consisting of halogenated aliphatic and .Iadd.halogenated .Iaddend.alkoxy-substituted .[.halogenated.]. aliphatic groups, wherein the method comprises the steps of: (a) reacting the halogenated aliphatic carboxylic acid compound with bromine trifluoride; and   (b) recovering the fluorinated product.   
     
     
       2. The method according to claim 1, wherein R is a halogenated aliphatic group selected from the group consisting of hexyl, pentyl, butyl, propyl, ethyl, and methyl. 
     
     
       3. The method according to claim 1, wherein R is a halogenated lower-alkoxy lower-alkyl group. 
     
     
       4. The method according to claim 3, wherein the lower-alkoxy group is selected from the group consisting of hexoxy, pentoxy, butoxy, propoxy, ethoxy, and methoxy. 
     
     
       5. The method according to claim 1, wherein bromine trifluoride and the halogenated aliphatic carboxylic acid compound are present in an equivalent ratio from about 2:3 to about 3:1 respectively. 
     
     
       6. The method according to claim 5, wherein bromine trifluoride and the halogenated aliphatic carboxylic acid compound are present in an equivalent ratio from about 2:3 to about 1:1, respectively. 
     
     
       7. The method according to claim 1, wherein the halogenated aliphatic carboxylic acid compound is reacted with bromine trifluoride in an inert solvent. 
     
     
       8. The method according to claim 7, wherein the inert solvent is selected from the group consisting of dichloromethane, chloroform, carbon tetrachloride, and mixtures thereof. 
     
     
       9. The method according to claim 1, wherein the halogenated aliphatic carboxylic acid compound is a fluorinated aliphatic carboxylic acid compound. 
     
     
       10. The method according to claim 9, wherein R is a fluorinated aliphatic group selected from the group consisting of hexyl, pentyl, butyl, propyl, ethyl, and methyl. 
     
     
       11. The method according to claim 9, wherein R is a fluorinated lower-alkoxy lower-alkyl group. 
     
     
       12. The method according to claim 11, wherein the lower-alkoxy group is selected from the group consisting of hexoxy, pentoxy, butoxy, propoxy, ethoxy, and methoxy. 
     
     
       13. The method according to claim 9, wherein bromine trifluoride and the fluorinated aliphatic carboxylic acid compound are present in an equivalent ratio from about 2:3 to about 3:1, respectively. 
     
     
       14. The method according to claim 13, wherein bromine trifluoride and the fluorinated aliphatic carboxylic acid compound are present in an equivalent ratio from about 2:3 to about 1:1, respectively. 
     
     
       15. The method according to claim 9, wherein the fluorinated aliphatic carboxylic acid compound is reacted with bromine trifluoride in an inert solvent. 
     
     
       16. The method according to claim 15, wherein the inert solvent is selected from the group consisting of dichloromethane, chloroform, carbon tetrachloride, and mixtures thereof. 
     
     
       17. The method according to claim 9, wherein the fluorinated aliphatic carboxylic acid compound is .[.1,1,1,3,3,3-hexafluoro-(2-propoxy)acetic.]. .Iadd.2-(1-trifluoromethyl-2,2,2-trifluoroethoxy)acetic .Iaddend.acid. 
     
     
       18. The method according to claim 9, wherein the fluorinated aliphatic carboxylic acid compound is (2,2,2-trifluoroethoxy)acetic acid. 
     
     
       19. The method according to claim 9, wherein the fluorinated product is 2-fluoromethoxy-1,1,1,3,3,3-hexafluoropropane. 
     
     
       20. The method according to claim 9, wherein the fluorinated product is fluoromethoxy-2,2,2-trifluoroethane.