Isomerization of 1,1,3,3-tetrafluoropropene
View Patent ↗The present invention involves methods for isomerization of 1234zc. Also provided are methods for managing 1,1,3,3-tetrafluoropropene produced as a byproduct in a process for synthesizing trans-1,3,3,3-tetrafluoropropene from 245fa, wherein 1234zc is converted into trans/cis-1234ze with the help of a catalyst in the absence of HF and in an isomerization reactor, or is converted into 1234zc and/or 245fa with the help of a catalyst in the presence of HF in a separate reactor or preferably in the same reactor of 245fa dehydrofluorination.
1. A method for isomerizing a compound comprising:
contacting a composition comprising 1,1,3,3-tetrafluoropropene with at least one isomerization catalyst selected from the group consisting of metal halides, halogenated metal oxides, and zero-valent metals or metal alloys, wherein said contacting occurs at a reaction temperature from about 50° C. to about 400° C. to isomerize at least a portion of said 1,1,3,3-tetrafluoropropene into 1,3,3,3-tetrafluoropropene.
2. The method of claim 1 wherein said 1,3,3,3-tetrafluoropropene is trans-1,3,3,3-tetrafluoropropene.
3. The method of claim 1 wherein said 1,3,3,3-tetrafluoropropene is cis-1,3,3,3-tetrafluoropropene.
4. The method of claim 1 wherein said 1,3,3,3-tetrafluoropropene is a mixture of cis-1,3,3,3-tetrafluoropropene and trans-1,3,3,3-tetrafluoropropene.
5. The method of claim 1 wherein said composition further comprises cis-1,3,3,3-tetrafluoropropene and/or 1,1,1,3,3-pentafluoropropane prior to said contacting.
6. The method of claim 1 wherein said isomerization is at least about 95% selective for 1,3,3,3-tetrafluoropropene.
7. The method of claim 1 wherein said isomerization converts at least about 95% of said 1,1,3,3-tetrafluoropropene.
8. The method of claim 1 wherein said contacting step occurs at a pressure of about 2 to about 6 atm.
9. The method of claim 1 wherein said contacting step occurs with a residence time of about 10 to about 60 seconds.
10. A method for producing a fluorinated compound comprising:
reacting a composition comprising 1,1,3,3-tetrafluoropropene in the presence of hydrogen fluoride and at least one catalyst selected from the group consisting of metal halides and halogenated metal oxides wherein said reacting occurs at a reaction temperature from about 100° C. to about 500° C. to convert at least a portion of said 1,1,3,3-tetrafluoropropene into a reaction product comprising at least one of 1,3,3,3-tetrafluoropropene and 1,1,1,3,3-pentafluoropropane.
11. The method of claim 10 wherein said reaction product comprises 1,3,3,3-tetrafluoropropene.
12. The method of claim 10 wherein said reaction product comprises 1,1,1,3,3-pentafluoropropane.
13. The method of claim 10 wherein said reacting comprises forming a reaction mixture comprising 1,1,3,3-tetrafluoropropene and hydrogen fluoride in a 1,1,3,3-tetrafluoropropene:hydrogen fluoride ratio of about 1:10 to about 1:1500.
14. The method of claim 10 wherein said reacting occurs in a vapor phase.
15. The method of claim 1 wherein said contacting step occurs at a pressure of about 1 to about 20 atm.
16. The method of claim 1 wherein said contacting step occurs with a residence time of about 0.5 to about 600 seconds.
17. The method of claim 10 wherein said reacting comprises forming a reaction mixture comprising 1,1,3,3-tetrafluoropropene and hydrogen fluoride in a 1,1,3,3-tetrafluoropropene:hydrogen fluoride ratio of about 1:0.1 to about 1:10000.
18. The method of claim 10 wherein said reacting comprises forming a reaction mixture comprising 1,1,3,3-tetrafluoropropene and hydrogen fluoride in a 1,1,3,3-tetrafluoropropene:hydrogen fluoride ratio of about 1:1 to about 1:2000.
19. The method of claim 10 wherein said contacting step occurs at a pressure of about 1 to about 20 atm.
20. The method of claim 10 wherein said contacting step occurs with a residence time of about 0.5 to about 600 seconds.