Process for the preparation of 1,1,1,3,3-pentafluoropropane

Abstract

1,1,1,3,3-pentafluoropropane is produced by reaction between 1,1,1,3,3-pentachloropropane and hydrogen fluoride in the presence of a hydrofluorination catalyst. The 1,1,1,3,3-pentachloropropane may advantageously be obtained by reaction between vinyl chloride and tetrachloromethane in the presence of a telomerization catalyst and of a nitrile.

1 - 18 . (canceled)  
   
   
       19 . In a process for the preparation of 1,1,1,3,3-pentafluoropropane according to which 1,1,1,3,3-pentachloropropane is reacted with hydrogen fluoride in the presence of a hydrofluorination catalyst, the improvement which comprises carrying out the reaction in a liquid reaction mixture at a temperature and a pressure at which the 1,1,1,3,3-pentafluoropropane is at least partially in gaseous form.  
   
   
       20 . The process according to  claim 19  which further comprises drawing off a gas stream containing 1,1,1,3,3-pentafluoropropane from the liquid reaction mixture whereby 1,1,1,3,3-pentafluoropropane is isolated from said reaction mixture.  
   
   
       21 . The process according to  claim 20 , wherein 1,1,1,3,3-pentafluoropropane is isolated continuously from the reaction mixture.  
   
   
       22 . The process according to  claim 20 , wherein the reaction is carried out continuously.  
   
   
       23 . The process of  claim 19 , which comprises conducting the reaction continuously in a liquid phase and maintaining a molar ratio of the catalyst to 1,1,1,3,3-pentachloropropane maintained from 0.001 to 1,000.  
   
   
       24 . The process of  claim 19 , wherein the molar ratio of the catalyst to 1,1,1,3,3-pentachloropropane is greater than 0.5.  
   
   
       25 . The process of  claim 19 , wherein 1,1,1,3,3-pentafluoropropane and hydrogen chloride are drawn off in the gaseous phase as they are being formed.  
   
   
       26 . The process of  claim 19 , wherein the hydrofluorination catalyst is selected from the group consisting of tin and antimony chlorides, fluorides and chlorofluorides.  
   
   
       27 . The process of  claim 19 , wherein the catalyst is antimony pentachloride.  
   
   
       28 . The process of  claim 19 , wherein from 5 to 100 moles of hydrogen fluoride are used per mole of 1,1,1,3,3-pentachloropropane.  
   
   
       29 . The process of  claim 19 , wherein the reaction is carried out at a temperature of approximately 50 to 150° C. and at a pressure from 2 to 40 bar.  
   
   
       30 . The process of  claim 19 , wherein the 1,1,1,3,3-pentachloropropane is prepared by reaction between vinyl chloride and tetrachloromethane.  
   
   
       31 . The process of  claim 19 , wherein the process is carried out in a reactor equipped with a device for drawing off a gas stream.  
   
   
       32 . The process of  claim 31 , wherein said device contains a distillation column and a reflux condenser mounted above the reactor.  
   
   
       33 . A process for the preparation of 1,1,1,3,3-pentafluoropropane which comprises reacting 1,1,1,3,3-pentachloropropane with hydrogen fluoride in the presence of a hydrofluorination catalyst, and which comprises carrying out the reaction in a liquid reaction mixture at a temperature and a pressure at which the 1,1,1,3,3-pentafluoropropane is at least partially in gaseous form.