Process for manufacture of 1,1,1,2-tetrafluoroethane

Abstract

An improved process is disclosed for the manufacture of 1,1,1,2-tetrafluoroethane by the vapor-phase reaction of 2-chloro-1,1,1-trifluoroethane with hydrogen fluoride in the presence of an inorganic chromium (III) catalyst which includes co-feeding molecular chlorine to extend catalyst activity.

I claim: 
     
       1. In a process for the manufacture of 1,1,1,2-tetrafluoroethane which comprises contacting, in the vapor phase at elevated temperature, a mixture of hydrogen fluoride and 2-chloro-1,1,1-trifluoroethane with an inorganic chromium (III) catalyst, the improvement comprising co-feeding an effective amount of elemental chlorine with said mixture of hydrogen fluoride and 2-chloro-1,1,1-trifluoroethane. 
     
     
       2. The process of claim 1 wherein said temperature is from about 300° C. to about 450° C., said mixture of hydrogen fluoride and 1,1,1-trifluoro-2-chloroethane is in molar ratio of hydrogen fluoride to 2-chloro-1,1,1-trifluoroethane of from about 2:1 to about 15:1 and said chlorine co-fee is from about 0.01 to 1 mol % chlorine based on the amount of 2-chloro-1,1,1-trifluoroethane. 
     
     
       3. The process of claim 2 wherein said chlorine co-feed is from about 0.03 to about 0.08 mol % chlorine based on the said 2-chloro-1,1,1-trifluoroethane. 
     
     
       4. The process of claim 3 wherein said temperature is from about 325° C. to about 400° C., said mixture of hydrogen fluoride and 2-chloro-1,1,1-trifluoroethane is in molar ratio of hydrogen fluoride to 2-chloro-1,1,1-trifluoroethane of from about 3:1 to about 0.08 and said chlorine co-feed is from about 0.06 to about 0.08 mol % chlorine based on the said 2-chloro-1,1,1-trifluoroethane.