Method for producing fluorinated alkane, method for separating and recovering amidine base, and method for using recovered amidine base

Abstract

A method for producing a fluorinated alkane represented by the formula (2): R2-F (R2 represents an alkyl group having 3 to 5 carbon atoms) is provided. An alcohol having 3 to 5 carbon atoms is fluorinated by a fluorinating agent represented by the formula (1): R1SO2F (R1 represents a methyl group, an ethyl group or an aromatic group) in the absence of a solvent, and in the presence of a phosphazene base.

1 . A method for producing a fluorinated alkane represented by the formula (2): R 2 -F (R 2  represents an alkyl group having 3 to 5 carbon atoms), wherein an alcohol having 3 to 5 carbon atoms is fluorinated by a fluorinating agent represented by the formula (1): R 1 SO 2 F (R 1  represents a methyl group, an ethyl group or an aromatic group) in the absence of a solvent, and in the presence of a phosphazene base. 
     
     
         2 . The method for producing a fluorinated alkane according to  claim 1 , wherein the reaction is performed by adding the fluorinating agent to the mixture of the alcohol having 3 to 5 carbon atoms and the base at 60° C. to 150° C. 
     
     
         3 . The method for producing a fluorinated alkane according to  claim 1 , wherein the fluorinating agent is methanesulfonyl fluoride. 
     
     
         4 . The method for producing a fluorinated alkane according to  claim 1 , wherein the fluorinated alkane is 2-fluorobutane. 
     
     
         5 . A method for separating and recovering an amidine base from an amidine base-sulfonate complex represented by the following formula (5): 
       
         
           
           
               
               
           
         
       
       (in the formula, R 1  represents a methyl group, an ethyl group or an aromatic group, and n is 0 or 2), the method comprising:
 a step (I) of adding an alkaline aqueous solution to a solution obtained by dissolving an amidine base-sulfonate complex in an aromatic hydrocarbon, to precipitate a sulfonic acid alkali metal salt; 
 a step (II) of adding water to the solution having the sulfonic acid alkali metal salt precipitated obtained in the step (I) to dissolve the sulfonic acid alkali metal salt, separating the aqueous layer having the sulfonic acid alkali metal salt dissolved and the layer of the aromatic hydrocarbon solution containing the amidine base from each other, and removing the aqueous layer having the sulfonic acid alkali metal salt dissolved; and 
 a step (III) of distilling off the aromatic hydrocarbon from the aromatic hydrocarbon solution containing the amidine base obtained in the step (II). 
 
     
     
         6 . The method for separating and recovering an amidine base according to  claim 5 , wherein the amidine base-sulfonate complex is obtained from the reaction mixture obtained by performing a reaction of fluorinating an alcohol having 3 to 5 carbon atoms, by using a fluorinating agent represented by the formula (1): R 1 SO 2 F (R 1  represents a methyl group, an ethyl group, or an aromatic group) in the absence of a solvent and in the presence of an amidine base represented by the following formula (4): 
       
         
           
           
               
               
           
         
       
       (in the formula, n is 0 or 2). 
     
     
         7 . The method for separating and recovering an amidine base according to  claim 5 , wherein the amidine base-sulfonate complex is 1,8-diazabicyclo[5.4.0]undec-7-ene-methanesulfonate complex. 
     
     
         8 . The method for separating and recovering an amidine base according to  claim 5 , comprising, after the step (II) and before the step (III), a step (IV) of removing moisture contained in the aromatic hydrocarbon solution containing the amidine base obtained in the step (II). 
     
     
         9 . The method for separating and recovering an amidine base according to  claim 8 , wherein the step (IV) is a step of removing the moisture contained in the aromatic hydrocarbon solution containing the amidine base obtained in the step (II) by using a Dean-Stark water separator. 
     
     
         10 . The method for separating and recovering an amidine base according to  claim 5 , wherein the amidine base is 1,8-diazabicyclo[5.4.0]undec-7-ene. 
     
     
         11 . A method for using a recovered amidine base, wherein the amidine base separated and recovered by the method according to  claim 5  is used as the base in the reaction of producing a fluorinated alkane represented by the formula (2): R 2 -F (R 2  represents an alkyl group having 3 to 5 carbon atoms) by fluorinating an alcohol having 3 to 5 carbon atoms in the presence of a base by a fluorinating agent represented by the formula (1): R 1 SO 2 F (R 1  represents a methyl group, an ethyl group or an aromatic group).