Processes for selective dehydrohalogenation of halogenated alkanes
View Patent ↗Disclosed are processes for producing halogenated olefins, and preferably tetrafluorinated propene(s), from one or more alkanes having both fluorine substituents and non-fluorine substituents, preferably with a high degree of conversion and selectivity. Preferably the process comprises the use of a catalyzed reaction in which the catalyst is selected from the group consisting of activated carbons, halogentated mono- and di-valent metal oxides, mono- and di-valent Lewis acid metal halides, zero-valent metals, and combinations of these.
1. A process for the production of fluorinated olefins comprising exposing, in a gas phase, a fluorinated and chlorinated alkane stream comprising HCFC-244fa to conditions effective to convert at least about 70% by weight of said alkane stream to an olefin stream comprising HFO-1234ze, wherein said exposing step comprises exposing said alkane stream to a catalyst selected from the group consisting of LiF, NaF, KF, MgF 2 , NiF 2 , LiCl, KCl, MgCl 2 , NiCl 2 , CuCl 2 , ZnCl 2 , NaCl, CsCl, CsF, activated carbon, Fe, Co, Ni, Cu, and combinations of two or more of these, wherein said catalyst is optionally supported by a substrate selected from the group consisting of carbon, activated carbon, graphite, fluorinated graphite, and combinations of two or more of these.
2. The process of claim 1 wherein said exposing step comprises conditions effective to convert at least about 80% by weight of said alkane stream comprising HCFC-244fa to said olefin stream comprising HFO-1234ze.
3. The process of claim 1 wherein said exposing step comprises conditions effective to convert at least about 90% by weight of said alkane stream comprising HCFC-244fa to said olefin stream comprising HFO-1234ze.
4. The process of claim 1 wherein said HFO-1234ze comprises trans-HFO-1234ze.
5. The process of claim 1 wherein said HFO-1234ze comprises cis-HFO-1234ze.
6. The process of claim 1 wherein said HFO-1234ze consists essentially of a mixture of cis-HFO-1234ze and trans-HFO-1234ze.
7. The process of claim 1 wherein said catalyst is LiCl supported on by a carbon substrate.
8. The process of claim 1 wherein said exposing step is conducted under a reaction temperature condition of from about 300° C. to less than about 400° C.
9. The process of claim 1 wherein said exposing step is conducted under a reaction temperature condition of from about 325° C. to about 375° C.
10. The process of claim 1 wherein said exposing step is conducted under a reaction temperature condition of about 350° C.
11. The process of claim 1 wherein said exposing step is conducted under a reaction pressure condition of from about 5 ton to about 200 psig.