Process for the preparation of trifluorinated and tetrafluorinated compounds
The subject of the invention is a process for the preparation of 2,3-dichloro-1,1,1-trifluoropropane by chlorination of 3,3,3-trifluoropropene at a pressure greater than 2 bar. Application in the synthesis of 1234yf.
1. A process for the preparation of 2,3-dichloro-1,1,1-trifluoropropane, comprising chlorinating by chlorination of 3,3,3-trifluoro-propene at a pressure greater than 2 bars.
2. The process according to claim 1 , wherein the pressure is 4 to 50 bars.
3. The process according to claim 1 , carried out in liquid phase.
4. The process according to claim 1 , carried out in absence of added catalyst.
5. A process for the preparation of 2,3,3,3-tetrafluoro-1-propene, comprising:
(i) chlorinating 3,3,3-trifluoropropene to 2,3-di-chloro-1,1,1-trifluoropropane by the process of claim 1 ;
(ii) dehydrochlorinating the 2,3-dichloro-1,1,1-tri-fluoropropane obtained to 2-chloro-3,3,3-trifluoro-1-propene;
(iii) fluorinating the 2-chloro-3,3,3-trifluoro-1-propene obtained to 2,3,3,3-tetrafluoro-1-propene.
6. The process according to claim 5 , in which (iii) is a direct catalytic fluorination.
7. The process according to claim 5 , in which (iii) comprises (iii a ) hydrofluorinating to 1,1,1,2-tetrafluoro-2-chloropropane and (iii b ) hydrofluorinating to 2,3,3,3-tetrafluoro-1-propene.
8. The process according to claim 5 , in which (ii) and (iii) are carried out in gaseous phase.
9. The process according to claim 5 , in which (ii) is carried out in presence of hydrogen.
10. The process according to claim 5 , in which dehydrochlorination is carried out in the presence of HF in an HF/starting product ratio of 1/1 to 5/1.
11. The process according to claim 2 , wherein the pressure is 5 to 20 bars.
12. The process according to claim 2 , wherein the pressure is autogeneous.