Integrated process for fluoro-olefin production
View Patent ↗Disclosed is a process for the manufacture of HFO-1234yf from TCP in three integrated steps that include hydrofluorination of TCP (tetrachloropropene) to HCFC-1233xf in the vapor phase followed by hydrofluorination of HCFC-1233xf to HCFC-244bb in the liquid phase which is then followed by dehydrochlorination in liquid or vapor phase to produce HFO-1234yf. The vapor phase hydrofluorination is carried out at a higher pressure than the liquid phase hydrofluorination, thereby eliminating the need for compression and/or intermediate recovery. Also, any HCl generated from this reaction is fed to the liquid phase hydrofluorination section to promote agitation and mixing. This results in a more economical process from an initial capital and operating cost versus conducting the 3-steps sequentially.
1. A process for the manufacture of HFO-1234yf from 1,1,2,3-tetrachloropropene (TCP) in three integrated steps comprising;
hydrofluorinating TCP in a vapor phase at a first pressure to form an HCFC-1233xf containing effluent comprising HCFC-1233xf and HCl;
hydrofluorinating HCFC-1233xf in a liquid phase or a liquid phase followed by vapor phase at a second pressure that is lower than the first pressure to form an HCFC-244bb containing effluent, wherein HCl from the HCFC-1233xf containing effluent is also provided to the hydrofluorination of HCFC-1233xf; and
dehydrochlorinating HCFC-244bb in a liquid or vapor phase to produce a HFO-1234yf containing effluent.
2. The process of claim 1 , wherein the TCP is hydrofluorinated in the presence of a catalyst selected from the group consisting of Cr 2 O 3 , Sb/C, FeCl 3 , Cr 2 O 3 /Al 2 O 3 , Cr 2 O 3 /AlF 3 , Cr 2 O 3 /C, CoC 2 /Cr 2 O/Al 2 O 3 , NiCl 2 /Cr 2 O 3 /Al 2 O 3 , CoCl 2 /AlF 3 and combinations thereof.
3. The process of claim 1 , wherein the hydrofluorination of TCP occurs in a reactor selected from the group consisting of a single reactor, a multistage reactor, or a series of reactors, using a combination of one or more recycle streams, HF and TCP.
4. The process of claim 1 , wherein the HCFC-1233xf containing effluent further comprises HCl, excess HF and unreacted TCP.
5. The process of claim 4 , wherein unreacted TCP is separated from the HCFC-1233xf effluent and recycled.
6. The process of claim 1 , wherein HCFC-1233xf is hydrofluorinated in the presence of a catalyst selected from the group consisting of SbCl 3 , SbCl 5 , SbF 5 , TiCl 4 , SnCl 4 and combinations thereof.
7. The process of claim 1 , wherein the HCFC-244bb containing effluent further comprises HCl, excess HF, and unreacted HCFC-1233xf.
8. The process of claim 7 , wherein unreacted HCFC-1233xf is separated from the HCFC-244bb effluent and recycled.
9. The process of claim 7 , wherein the HCFC-244bb effluent is treated with a catalyst stripper to remove unreacted HF and any catalyst that is present.
10. The process of claim 9 , wherein the unreacted HF and catalyst are recycled.
11. The process of claim 9 , wherein, after treatment with the catalyst stripper, HCl is removed from the HCFC-244bb effluent.
12. The process of claim 7 , wherein, after treatment with the catalyst stripper, the unreacted HCFC-1233xf in the HCFC-244bb effluent is hydrofluorinated in the presence of a catalyst to form a second HCFC-244bb effluent.
13. The process of claim 12 , wherein the catalyst is SbCl 5 supported on carbon.
14. The process of claim 12 , wherein, after the unreacted HCFC-1233xf is hydrofluorinated, HCl is removed from the second HCFC-244bb effluent.
15. The process of claim 7 , wherein excess HF is recovered from the HCFC-244bb effluent.
16. The process of claim 15 , wherein HF is recovered by cooling and phase separation of the HCFC-244bb effluent to provide a first layer rich in organics and a second layer rich in HF.
17. The process of claim 15 , wherein the HF is recovered by phase separation and azeotropic distillation.
18. The process of claim 15 , wherein the HF is recovered by absorption into sulfuric acid.
19. The process of claim 1 , wherein HCFC-244bb is dehydrochlorinated in the vapor phase in the presence of a catalyst comprising Cr 2 O 3 .
20. The process of claim 1 , wherein HCFC-244bb is dehydrochlorinated in the vapor phase in the presence of at least one metal halide catalyst.
21. The process of claim 20 , wherein the metal halide catalyst is a mono-, bi-, or tri-valent metal halide.
22. The process of claim 20 , wherein a component metal of the metal halide catalyst is selected from the group consisting of Cr 3+ , Fe 3+ , Mg 2+ , Ca 2 +, Ni 2 +, Zn 2+ , Pd 2+ , Li + , Na + , K + , and Cs + and a component halogen of the metal halide catalyst is selected from the group consisting of F − , Cl − , Br − , and I − .
23. The process of claim 20 , wherein the metal halide catalyst is selected from the group consisting of LiF, NaF, KF, CsF, MgF 2 , CaF 2 , LiCl, NaCl, KCl, CsCl and combinations thereof.
24. The process of claim 1 , wherein HCFC-244bb is dehydrochlorinated in the liquid phase in the presence of an aqueous base solution.
25. The process of claim 24 , wherein the aqueous base solution is either NaOH or KOH.
26. The process of claim 1 , wherein the HFO-1234yf effluent further comprises HCl and unreacted HCFC-244bb.
27. The process of claim 26 , wherein the HFO-1234yf effluent is deacidified in absorption equipment, then dried and compressed.
28. The process of claim 27 wherein HFO-1234yf is recovered and unreacted HCFC-244bb is recycled.