Catalytic gas phase fluorination of 1233xf to 1234yf
View Patent ↗The present invention provides a process for preparing 1234yf, comprising: (i) contacting 1233xf with hydrogen fluoride HF in gas phase in the presence of a fluorination catalyst under conditions sufficient to produce a reaction mixture; (ii) separating the reaction mixture into a first stream comprising HCl, 1234yf and a second stream comprising HF, unreacted 1233xf and 245cb; (iii) recycling at least a part of the second stream at least in part back to step (i). The present invention also provides a process for preparing 1234yf, comprising: (i) contacting 1233xf with hydrogen fluoride HF in gas phase in the presence of a fluorination catalyst under conditions sufficient to produce a reaction mixture; (ii) separating the reaction mixture into HCl and a stream containing the fluorinated products; (iii) separating said stream containing the fluorinated products into a first stream comprising 1234yf and a second stream comprising HF, unreacted 1233xf and 245cb; (iv) recycling at least a part of the second stream at least in part back to step (i).
1. A process for preparing 2,3,3,3-tetrafluoropropene (1234yf), comprising:
(i) contacting 2-chloro-3,3,3-trifluoro-1-propene (1233xf) with hydrogen fluoride HF in the gas phase in the presence of a fluorination catalyst under conditions sufficient to produce a reaction mixture;
(ii) separating the reaction mixture into a first stream comprising HCl and 2,3,3,3-tetrafluoropropene (1234yf), and a second stream comprising HF, unreacted 2-chloro-3,3,3-trifluoro-1-propene (1233xf), and 1,1,1,2,2-pentafluoropropane (245cb);
(iii) recycling at least a part of the second stream comprising unreacted 2-chloro-3,3,3,-trifluoro-1-propene (1233xf) and 1,1,1,2,2-pentafluoropropane (245cb) back to step (i),
wherein an equilibrium between 1,1,1,2,2-pentafluoropropane (245cb) and 2,3,3,3-tetrafluoropropene (1234yf) is displaced to 2,3,3,3-tetrafluoropropene (1234yf), and
(iv) converting at least a portion of the unreacted 2-chloro-3,3,3,-trifluoro-1-propene (1233xf) into 2,3,3,3-tetrafluoropropene (1234yf).
2. The process of claim 1 , further comprising separating the first stream into HCl and 2,3,3,3-tetrafluoropropene (1234yf).
3. A process for preparing 2,3,3,3-tetrafluoropropene (1234yf), comprising:
(i) contacting 2-chloro-3,3,3-trifluoro-1-propene (1233xf) with hydrogen fluoride HF in the gas phase in the presence of a fluorination catalyst under conditions sufficient to produce a reaction mixture;
(ii) separating the reaction mixture into HCl and a stream comprising fluorinated products;
(iii) separating said stream comprising fluorinated products into a first stream comprising 2,3,3,3-tetrafluoropropene (1234yf) and a second stream comprising HF, unreacted 2-chloro-3,3,3-trifluoro-1-propene (1233xf), and 1,1,1,2,2-pentafluoropropane (245cb);
(iv) recycling at least a part of the second stream comprising unreacted 2-chloro-3,3,3,-trifluoro-1-propene (1233xf) and 1,1,1,2,2-pentafluoropropane (245cb) back to step (i),
wherein an equilibrium between 1,1,1,2,2-pentafluoropropane (245cb) and 2,3,3,3-tetrafluoropropene (1234yf) is displaced to 2,3,3,3-tetrafluoropropene (1234yf), and
(v) converting at least a portion of the unreacted 2-chloro-3,3,3,-trifluoro-1-propene (1233xf) into 2,3,3,3-tetrafluoropropene (1234yf).
4. The process of claim 1 , wherein the reaction mixture obtained in step (i) comprises 2,3,3,3-tetrafluoropropene (1234yf) and 1,1,1,2,2-pentafluoropropane (245cb) in a molar ratio ranging from 1:5 to 3:1.
5. The process of claim 4 , wherein the reaction mixture obtained in step (i) comprises 2,3,3,3-tetrafluoropropene (1234yf), 1,1,1,2,2-pentafluoropropane (245cb), and 1,1,1,2-tetrafluoro-2-chloropropane (244bb), wherein the molar ratio of 245cb to 244bb ranges from 1:1 to 70:1.
6. The process of claim 3 , wherein the reaction mixture obtained in step (i) comprises 2,3,3,3-tetrafluoropropene (1234yf) and 1,1,1,2,2-pentafluoropropane (245cb) in a molar ratio ranging from 1:5 to 3:1.
7. The process of claim 1 , wherein the reaction mixture obtained in step (i) comprises 2,3,3,3-tetrafluoropropene (1234yf), 1,1,1,2,2-pentafluoropropane (245cb), and 1,1,1,2-tetrafluoro-2-chloropropane (244bb), wherein the molar ratio of 245cb to 244bb ranges from 1:1 to 70:1.
8. The process of claim 1 , wherein the molar ratio of HF to 1233xf in step (i) ranges from 3:1 to 150:1.
9. The process of claim 3 , wherein the molar ratio of HF to 1233xf in step (i) ranges from 3:1 to 150:1.
10. The process of claim 1 , wherein step (i) is carried out at a pressure ranging from 3 to 20 bars.
11. The process of claim 3 , wherein step (i) is carried out at a pressure ranging from 3 to 20 bars.
12. The process of claim 1 , wherein step (i) is carried out at a temperature ranging from 200 to 450° C.
13. The process of claim 3 , wherein step (i) is carried out at a temperature ranging from 200 to 450° C.
14. The process of claim 1 , wherein step (i) is carried out with a contact time ranging from 6 to 100 sec.
15. The process of claim 3 , wherein step (i) is carried out with a contact time ranging from 6 to 100 sec.
16. The process of claim 1 , wherein step (i) is carried out in the presence of O 2 and/or Cl 2 .
17. The process of claim 16 , wherein the ratio of O 2 and/or Cl 2 to 2-chloro-3,3,3-trifluoro-1-propene (1233xf) ranges from 0.05 to 15 mole %.
18. The process of claim 3 , wherein step (i) is carried out in the presence of O 2 and/or Cl 2 .
19. The process of claim 18 , wherein the ratio of O 2 and/or Cl 2 to 2-chloro-3,3,3-trifluoro-1-propene (1233xf) ranges from 0.05 to 15 mole %.
20. The process of claim 1 , wherein the step of separating into a first stream and a second stream comprises a distillation step.
21. The process of claim 3 , wherein the step of separating into a first stream and a second stream comprises a distillation step.
22. The process of claim 1 , wherein step (i) is carried out in the presence of a polymerization inhibitor.
23. The process of claim 22 , wherein the polymerization inhibitor comprises p-methoxyphenol, t-amylphenol, limonene, d,l-limonene, a quinone, a hydroquinone, an epoxide, an amine, or a mixture thereof.
24. The process of claim 3 , wherein step (i) is carried out in the presence of a polymerization inhibitor.
25. The process of claim 24 , wherein the polymerization inhibitor comprises p-methoxyphenol, t-amylphenol, limonene, d,l-limonene, a quinone, a hydroquinone, an epoxide, an amine, or a mixture thereof.
26. The process of claim 1 , wherein step (i) is carried out in the presence of a catalyst comprising Ni—Cr.
27. The process of claim 3 , wherein step (i) is carried out in the presence of a catalyst comprising Ni—Cr.
28. The process of claim 1 , wherein said catalyst is supported on a support comprising fluorinated alumina, fluorinated chromia, fluorinated activated carbon, graphite carbon, or a combination thereof.
29. The process of claim 3 , wherein said catalyst is supported on a support comprising fluorinated alumina, fluorinated chromia, fluorinated activated carbon, graphite carbon, or a combination thereof.
30. The process of claim 1 , wherein step (i) is carried out in the presence of a supported or unsupported chromium catalyst.
31. The process of claim 3 , wherein step (i) is carried out in the presence of a supported or unsupported chromium catalyst.
32. The process of claim 1 , wherein said fluorination catalyst comprises a co-catalyst comprising Ni, Co, Zn, Mn, or a mixture thereof.
33. The process of claim 32 , wherein the amount of co-catalyst ranges from about 1-10 wt % of said fluorination catalyst.
34. The process of claim 3 , wherein said fluorination catalyst comprises a co-catalyst comprising Ni, Co, Zn, Mn, or a mixture thereof.
35. The process of claim 34 , wherein the amount of co-catalyst ranges from about 1-10 wt % of said fluorination catalyst.
36. The process of claim 1 , further comprising activating the fluorination catalyst with a fluorine-comprising compound.
37. The process of claim 3 , further comprising activating the fluorination catalyst with a fluorine-comprising compound.
38. The process of claim 1 , wherein said process is continuous.
39. The process of claim 3 , wherein said process is continuous.