Purification of desflurane containing R-123

Abstract

A process for preparing 2-difluoromethoxy-1,1,1,2-tetrafluoroethane (desflurane) comprising the following steps: (a) providing a first mixture comprising desflurane and 2,2-dichloro-1,1,1-trifluoroethane (R-123); (b) adding water to the first mixture to form a second mixture; and (c) fractionally distilling the second mixture to yield a desflurane product purer in R-123 than said the mixture. Also described is a purified desflurane product prepared by the process, and intermediate products comprising water added to a mixture of desflurane and R-123.

1. A process for preparing 2-difluoromethoxy-1,1,1,2-tetrafluoroethane (desflurane) comprising the following steps:
 (a) providing a first mixture comprising desflurane and 2,2-dichloro-1,1,1-trifluoroethane (R-123);  
 (b) adding water to said first mixture to form a second mixture; and  
 (c) fractionally distilling said second mixture to yield a desflurane product purer in R-123 than said first mixture.  
 
   
   
     2. The process according to  claim 1 , wherein said first mixture comprises 1% or less by weight of R-123. 
   
   
     3. The process according to  claim 1 , wherein the first mixture is an anesthetic grade desflurane. 
   
   
     4. The process according to  claim 1 , wherein the amount of water added to said first mixture is 1 to 100% by weight based on the total weight of the first mixture. 
   
   
     5. The process according to  claim 4 , wherein the amount of water added to said first mixture is 3 to 15% by weight based on the total weight of the first mixture. 
   
   
     6. A composition of matter comprising:
 (a) desflurane;  
 (b) R-123; and  
 (c) water.  
 
   
   
     7. The composition according to  claim 6 , which contains 1 to 100% by weight of water based on the total weight of the combination of desflurane and R-123. 
   
   
     8. The composition according to  claim 7 , which contains 3 to 15% by weight of water based on the total weight of the combination of desflurane and R-123. 
   
   
     9. A composition of matter comprising desflurane in admixture with R-123, wherein the amount of R-123 is less than 200 ppm. 
   
   
     10. The composition according to  claim 9 , wherein the amount of R-123 is less than 40 ppm. 
   
   
     11. The composition according to  claim 10 , wherein the amount of R-123 is less than 5 ppm.