Process for preparing 2,3,3,3-tetrafluoropropene (1234yf)

• US 8,536,388 B2
• Filed: 04/09/2009
• Issued: 09/17/2013
• Est. Priority Date: 10/03/2006
• Status: Active Grant

• Current Assignee: Mexichem, S.A.B. De C.V. (Orbia Advance Corporation, S.A.B. de C.V.)
• Original Assignee: Mexichem, S.A.B. De C.V. (Orbia Advance Corporation, S.A.B. de C.V.)
• Inventors: Smith, John W., McGuiness, Claire E, Sharratt, Andrew Paul
• Primary Examiner(s): Katakam, Sudhakar
• Application Number:
  US12/736,444
• Publication Number:
  US 20110124930A1
• Time in Patent Office: 1,622 Days
• Field of Search: None
• US Class Current: 570/158
• CPC Class Codes: C07C 17/087 to unsaturated halogenated hydrocarbons
• CPC Class Codes: C07C 17/206 the other compound being HX
• CPC Class Codes: C07C 17/25 by splitting-off hydrogen halides from halogenated hydrocarbons
• CPC Class Codes: C07C 17/275 of hydrocarbons and halogenated hydrocarbons
• CPC Class Codes: C07C 19/01 containing chlorine
• CPC Class Codes: C07C 19/08 containing fluorine
• CPC Class Codes: C07C 19/10 and chlorine
• CPC Class Codes: C07C 21/18 containing fluorine

Abstract

The present invention provides a process for its preparation comprising (a) converting 1,1,1-trifluoro-2,3-dichloropropane (243db) to 3,3,3-trifluoro-2-chloro-prop-1-ene (CF₃CCI═CH₂) in the presence of a first catalyst in a first reactor, (b) contacting CF₃CCI═CH₂ with a fluorinating agent in the presence of a second catalyst in a second reactor to produce a compound of formula CF₃CFXCH₃, wherein X═Cl or F, and (c) dehydrohalogenating the compound of formula CF₃CFXCH₃ to produce 2,3,3,3-tetrafluoropropene (1234yf).

Claims

1. A process for preparing 2,3,3,3-tetrafluoropropene (1234yf), the process comprising:

(a) converting 1,1,1-trifluoro-2,3-dichloropropane (243 db) to 3,3,3-trifluoro-2-chloro-prop-1-ene (CF₃CCl═

CH₂, 1233xf) in the presence of a first catalyst in a first reactor;

(b) contacting 1233xf with a fluorinating agent in the presence of a second catalyst in a second reactor to produce a compound of formula CF₃CFXCH₃, wherein X═

Cl or F; and

(c) dehydrohalogenating the compound of formula CF₃CFXCH₃ to produce 1234yf,

wherein the first catalyst and second catalyst are selected from catalysts comprising activated carbon, catalysts comprising alumina, catalysts comprising an oxide of a transition metal, Lewis acid metal halide catalysts and mixtures thereof.

2. A process of claim 1 wherein step (a) is carried out at a temperature of from about −

70 to about 450°

C. and a pressure of from 0 to about 30 bara.

3. A process according to claim 1 wherein step (b) is carried out at a temperature of from about −

100 to about 400°

C. and a pressure of from 0 to about 50 bara.

4. A process according to claim 1 wherein the fluorinating agent is hydrogen fluoride (HF).

5. A process according to claim 1 wherein step (b) is carried out in the vapour phase.

6. A process of claim 5 wherein the second catalyst comprises activated carbon, alumina and/or an oxide of a transition metal.

7. A process of claim 5 wherein step (b) is carried out at a temperature of from about 0 to about 390°

C. and a pressure of from 0.1 to about 30 bara, preferably at a temperature of from about 200 to about 370°

C. and a pressure of from about 1 to about 10 bara.

8. A process of claim 1 wherein step (b) is carried out in the liquid phase.

9. A process of claim 8 wherein the second catalyst is a Lewis acid metal halide catalyst.

10. A process of claim 8 wherein step (b) is carried out at a temperature of from about −

50 to about 250°

C. and a pressure of from about 1 to about 50 bara, preferably at a temperature of from about 10 to about 150°

C. and a pressure of from about 10 to about 30 bara.

11. A process of claim 1 wherein step (a) is conducted in the presence of HF.

12. A process of claim 11 wherein the molar ratio of HF:

organics in step (a) is from about 0.01;

1 to about 50;

1, preferably from about 2;

1 to about 15;

1.

13. A process of claim 4 wherein the molar ratio of HF:

organics in step (b) is from about 1;

1 to about 100;

1, preferably from about 5;

1 to about 40;

1.

14. A process of claim 1 wherein the 1233xf produced in step (a) is purified before being passed to the second reactor in step (b).

15. A process of claim 1 wherein step (c) is carried out at a temperature of from about −

70 to about 1000°

C. and a pressure of from about 1 to about 30 bara.

16. A process of claim 1 wherein step (c) is carried out by metal catalysed dehydrohalogenation.

17. A process of claim 16 wherein step (c) is carried out at a temperature of from about 0 to about 400°

C. and a pressure of from 0.01 to about 25 bara, preferably from about 200 to about 360°

C. and from about 1 to about 10 bara.

18. A process of claim 16 wherein step (c) is conducted in the presence of HF.

19. A process of claim 18 wherein the wherein the molar ratio of HF:

organics in step (c) is from about 0.01;

1 to about 50;

1, preferably from about 2;

1 to about 15;

1.

20. A process of claim 16 wherein step (c) is carried out simultaneously with step (b).

21. A process of claim 15 wherein step (c) is carried out by contacting the compound of formula CF₃CFXCH₃ with a base.

22. A process of claim 21 wherein step (c) is carried out at a temperature of from about −

50 to about 300°

C., preferably from about 20 to about 250°

C.

23. A process of claim 21 wherein the base is selected from the group consisting of:

a metal hydroxide, an alkali metal hydroxide, including sodium hydroxide and potassium hydroxide, an alkaline earth metal hydroxide, including calcium hydroxide a metal amide and mixtures thereof.

24. A process of claim 21 wherein step (c) is carried out in a solvent, preferably wherein the solvent is selected from water, alcohols, diols, polyols, polar aprotic solvents and mixtures thereof, and wherein the process optionally is carried out in the presence of a co-solvent or diluent.

25. A process according to claim 21 wherein step (c) is carried out in the presence of a catalyst.

26. A process of claim 1 comprising the step (iii) of contacting 3,3,3-trifluoropropene (1243zf) with a compound of formula AB to produce a compound of formula CF₃CHACH₂B, wherein A and B represent, independently, H, F, Cl, Br or I, provided that A and B are not both H or F, preferably wherein AB is chlorine and CF₃CHACH₂B is 243 db.

27. A process according to claim 26 comprising the step (ii) of converting 1,1,1,3-tetrachloropropane (250th) to 3,3,3-trifluoropropene (1243zf).

29. A process according to claim 27 comprising the step (i) of telomerising ethylene and carbon tetrachloride (CCL₄) to produce the 1,1,1,3-tetrachlororopane.

30. The process according to claim 25, wherein the catalyst is a crown ether or a quaternary ammonium salt.

28. A process for preparing 1234yf, the process comprising:

(i) telomerising ethylene and carbon tetrachloride (CCl₄) to produce 1,1,1,3-tetrachloropropane (250 fb);

(ii) converting 250fb to 3,3,3-trifluoropropene (1243zf);

(iii) contacting 1243zf with a compound of formula AB to produce a compound of formula CF₃CHACH₂B, wherein A and B represent, independently, H, F, Cl, Br or I, provided that A and B are not both H or F;

(iv) converting the compound of formula CF₃CHACH₂B to 1233xf in the presence of a first catalyst in a first reactor;

(v) contacting 1233xf with a fluorination agent in the presence of a second catalyst in a second reactor to produce a compound of formula CF₃CFXCH₃, wherein X═

Cl or F; and

(vi) dehydrohalogenating the compound of formula CF₃CFXCH₃ to produce 1234y,

wherein the first catalyst and second catalyst are selected from catalysts comprising activated carbon, catalysts comprising alumina, catalysts comprising an oxide of a transition metal, Lewis acid metal halide catalysts and mixtures thereof.