Process for producing 2,3,3,3-tetrafluoropropene

Patent metadata

Field	Value
Publication number	US-9493384-B2
Application number	US-201214348804-A
Country	US
Kind code	B2
Filing date	Sep 29, 2012
Priority date	Jul 6, 2007
Publication date	Nov 15, 2016
Grant date	Nov 15, 2016

Abstract

The present invention relates, in part, to the discovery that the presence of HF in a HCFC-244bb feedstream in a reaction for the preparation of HFO-1234yf results in selectivity changeover from HFO-1234yf to HCFO-1233xf. By substantially removing HF, it is shown that the selectivity to HFO-1234yf via dehydrochlorination of HCFC-244bb is improved.

First claim

What is claimed is:

1. A method for enhancing the selectivity of 2-chloro-1,1,1,2-tetrafluoropropane to 2,3,3,3-tetrafluoropropene in a dehydrochlorination reaction which comprises:
contacting a starting composition comprising 2-chloro-1,1,1,2-tetrahydrofluoropropane with a dehydrochlorination catalyst in a dehydrochlorination reactor that is substantially free of HF such that the amount of HF to the reactor is less than 5000 ppm to produce a final composition comprising 2,3,3,3-tetrafluoropropene.

2. The method of claim 1 , wherein the level of HF within the reactor is less than 500 ppm.

3. The method of claim 1 , wherein the level of HF within the reactor is less than 50 ppm.

4. The method of claim 1 , wherein reducing the HF level of the composition comprises the distilling of the HF, passing the composition through a scrubber, or passing the composition over a solid sorbent.

5. The method of claim 4 , wherein the solid sorbent is selected from the group consisting of alumina, calcium carbonate, sodium carbonate, and sodium aluminate.

6. The process according to claim 1 wherein the dehydrochlorination catalyst is a metal alloy or zero-valent metal.

7. The process according to claim 6 wherein the dehydrochlorination catalyst is Pt, Pd, Rh, Fe, Co, Ni, Cu, Mo, Mn, stainless steel or austenitic-nickel based alloy.

8. The process according to claim 1 conducted at a temperature ranging from about 200° C. to about 800° C.

9. The process according to claim 8 conducted at a temperature ranging from about 300° C. to about 600° C.

10. The process according to claim 9 conducted at temperature ranging from about 400° C. to about 500° C.

11. The process according to claim 1 conducted at a pressure ranging from about 0 to about 300 psig.

12. The process according to claim 11 conducted art a pressure ranging from about 10 to about 100 psig.

13. The process according to claim 12 conducted at a pressure ranging from about 20 to about 70 psig.

14. A process for preparing 2,3,3,3-tetrafluoropropene in a metal dehydrochlorination reactor, said process comprising contacting a starting composition comprising 2-chloro-1,1,1,2-tetrafluoropropane substantially free of HF with a dehydrochlorination catalyst in said reactor, to minimize the tendency of the metal in the reactor to form a hydrofluorination catalyst that catalyzes the formation of 2-chloro-3,3,3-trifluoropropene, said HF being present in amount of less than 5000 ppm.

15. The process according to claim 14 , wherein the HF is present in less than 500 ppm.

16. The process according to claim 15 , wherein the HF is present in less than 50 ppm.

17. The process according to claim 14 wherein the dehydrochlorination catalyst is a metal alloy or zero-valent metal.

18. The process according to claim 17 wherein the dehydrochlorination catalyst is Pt, Pd, Rh, Fe, Co, Ni, Cu, Mo, Mn, stainless steel or austenitic-nickel based alloy.

19. The process according to claim 14 conducted at a temperature ranging from about 200° C. to about 800° C.

20. The process according to claim 19 conducted at a temperature ranging from about 300° C. to about 600° C.

21. The process according to claim 20 conducted at temperature ranging from about 400° C. to about 500° C.

22. The process according to claim 14 conducted at a pressure ranging from about 0 to about 300 psig.

23. The process according to claim 22 conducted at a pressure ranging from about 10 to about 100 psig.

24. The process according to claim 23 conducted at a pressure ranging from about 20 to about 70 psig.

Assignees

• Honeywell Int Inc

Inventors

• Wang Haiyou
• Tung Hsueh Sung

Classifications

• C07C17/25 Primary

  by splitting-off hydrogen halides from halogenated hydrocarbons · CPC title

• C07B35/06

  Decomposition, e.g. elimination of halogens, water or hydrogen halides · CPC title

• B01J27/10

  Chlorides · CPC title

• B01J27/12

  Fluorides · CPC title

• B01J35/0006

  Operations & Transport · mapped topic