Process to manufacture 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb)
The invention provides an improved process to manufacture 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) by reacting 2-chloro-3,3,3,-trifluoropropene (HCFO-1233xf) with hydrogen fluoride, in a liquid phase reaction in the presence of hydrogen chloride and a liquid phase fluorination catalyst. The hydrogen chloride is added into the reaction from an external source at a pressure of about 100 psig or more. The HCFC-244bb is an intermediate in the production of 2,3,3,3-tetrafluoropropene-1 (HFO-1234yf).
1. A process for the production of 2,3,3,3-tetrafluoropropene which comprises:
(i) continuously reacting 2-chloro-3,3,3,-trifluoropropene with hydrogen fluoride, in a liquid phase reaction and co-feeding hydrogen chloride, in the presence of a liquid phase fluorination catalyst to produce a composition comprising 2-chloro-1,1,1,2-tetrafluoropropane, wherein the hydrogen chloride is added into the reaction from an external source at a pressure of about 100 psig or more;
(ii) dehydrohalogenating the 2-chloro-1,1,1,2-tetrafluoropropane under conditions effective to produce 2,3,3,3-tetrafluoropropene; wherein
(iii) said 2-chloro-3,3,3,-trifluoropropene is produced by a process comprising fluorinating 1,1,2,3-tetrachloropropene with hydrogen fluoride to produce an intermediate product comprising hydrogen fluoride, 2-chloro-3,3,3,-trifluoropropene and hydrogen chloride;
(iv) removing from said intermediate product at least a portion of said hydrogen chloride;
and (v) introducing at least a portion of the hydrogen chloride removed in said step (iv) into said liquid phase reaction of step (i).
2. The process of claim 1 wherein the reacting of step (i) is conducted in a liquid phase reaction vessel.
3. The process of claim 1 wherein the dehydrohalogenating reacting of step (ii) is conducted continuously.
4. The process of claim 1 wherein the mole ratio of hydrogen fluoride to 2-chloro-3,3,3-trifluoropropene fed to the reaction of step (i) is from about 1:1 to about 50:1.
5. The process of claim 1 wherein the mole ratio of hydrogen chloride to 2-choro-3,3,3-trifluoropropene fed to the reaction of step (i) is from about 0.1:1 to about 10:1.
6. The process of claim 1 wherein the liquid phase fluorination catalyst comprises SbCl 5 , SbCl 3 , SbF 5 , SnCl 4 , TaCl 5 , Tin 4 , NbCl 5 , MoCl 6 , FeCl 3 , CrF 3 , Cr2O3, a fluorinated species of SbCl 5 , a fluorinated species of SbCl 3 , a fluorinated species of SnCl 4 , a fluorinated species of TaCl 5 , a fluorinated species of TiCl 4 , a fluorinated species of NbCl 5 , a fluorinated species of MoCl 6 , a fluorinated species of FeCl 3 , a fluorinated species of Cr 2 O 3 , or combinations thereof.
7. The process of claim 1 wherein the reacting of step (i) is conducted at a temperature of from about 30° C. to about 200° C.
8. The process of claim 1 wherein the reacting of step (i) is conducted at a pressure of up to about 200 psia.