Process for isomerizing a (hydro)fluoropropene
A process for isomerising a (hydrohalo)fiuoroalkene, the process comprising contacting the (hydrohalo)fluoroalkene with a catalyst comprising an unsupported Lewis acid, a chromia-containing catalyst containing at least one additional metal, an alumina, a supported liquid catalyst, and mixtures thereof.
1. A process for isomerizing a (hydro)fluoropropene, the process comprising contacting the (hydro)fluoropropene with a zinc/chromia catalyst containing 0.1 to 20% by weight of zinc, wherein the (hydro)fluoropropene is selected from the monofluoropropene 1-fluoropropene (CH 3 CH═CHF), the difluoropropenes 1,2-difluoropropene (HFC═CFCH 3 ) and 1,3- difloropropene(HFC═CHCF 2 H), the trifluoropropenes 1,2,3,-trifluoropropene(HFC═CFCH 2 F) and 1,3,3trifluoropropene (HFC═CHCF 2 H), the tetrafluoropropenes 1,3,3,3-tetrafluoropropene (HFC═CHCF 3 ) and 1,2,3,3,tetrafloropropene(HFC═CFCF 2 H),and the pentafloropropene 1,2,3,3,3,-pentafloropropene (HFC═CFCF 3 ).
2. The process according to claim 1 wherein the isomerization results in the changing of the ratio of the E and Z isomers.
3. The process according to claim 2 wherein the ratio of the Z isomer to the E isomer increases.
4. The process according to claim 2 , wherein the isomerization is carried out as an in situ step in the synthesis of the (hydro) fluoropropene.
5. A process according to claim 4 wherein the isomerization results in a changing of the ratio of the E to Z isomer compared to what it would have been if the catalyst had not been utilized.
6. The process according to claim 2 wherein the ratio of E to Z isomers changes from that which is the kinetic equilibrium from the reaction preparing the (hydro) fluoropropene.
7. The process according to claim 1 wherein the resultant (hydro) fluoropropene is recovered.
8. The process according to claim 1 , wherein the zinc in the chromia-containing catalyst is present at a level of at least 1% by weight of the catalyst.
9. The process according to claim 1 , wherein the zinc in the chromia-containing catalyst is present at a level of no more than 10% by weight of the catalyst.
10. The process according to claim 1 conducted at a temperature of from −50 to 400 ° C.
11. The process according to claim 1 conducted at a pressure of from 0 to 30 bara.
12. The process according to claim 1 conducted in the presence of HF.
13. A process for making a (hydro) fluoropropene composition comprising a level of a Z isomer of (hydro) fluoropropene enhanced beyond the level of the Z isomer when the (hydro) fluoropropene was formed, or beyond the kinetic equilibrium level of the Z isomer, comprising the step of using a zinc/chromia catalyst containing 0.1 to 20% by weight of zinc, wherein the (hydro)fluoropropene is selected from the monofluoropropene 1-fluoropropene (CH 3 CH═CHF), the difluoropropenes 1,2-difluoropropene (HFC═CFCH 3 ) and 1,3-difluoropropene (HFC═CHCH 2 F), the trifluoropropenes 1,2,3trifluoropropene (HFC═CFCH 2 F) and 1,3,3-trifluoropropene (HFC═CHCF 2 H), the tetrafluoropropenes 1,3,3,3-tetrafluoropropene (HFC═CHCF 3 ) and 1,2,3,3-tetrafluoropropene (HFC═CFCF 2 H), and the pentafluoropropene 1,2,3,3,3-pentafluoropropene (HFC═CFCF 3 ).
14. A process according to claim 13 in which the step which enhances the level of Z isomer in the compositions is a clean up step.
15. A process according to claim 1 wherein the (hydro)fluoropropene is 1,2,3,3,3-pentafluoropropene (CF 3 CF═CHF).
16. A process according to claim 1 wherein the (hydro)fluoropropene is 1,3,3,3-tetrafluoropropene (CF 3 CH═CHF).