Process for the manufacture of fluorinated olefins
View Patent ↗Provided are methods for producing fluorinated organic compounds, which preferably comprises converting at least one compound of formula (I) CH 2 XCHZCF 3 to at least one compound of formula (II) CHX═CZCF 3 where X and Z are independently H or F, with the proviso that X and Z are not the same. The converting step comprises catalytically reacting at least one compound of formula (I), preferably via dehydrogenation or oxidative dehydrogenation. In another aspect, the inventive method of preparing fluorinated organic compounds comprises converting a reaction stream comprising at least one pentafluoropropene to a product stream comprising at least one pentafluoropropane and at least one compound of formula (I), separating out the compound of formula (I) from the product stream, and converting the compound of formula (I) separated from the product stream to at least one compound of formula (II), wherein the conversion the compound of formula (I) to 3,3,3-trifluoropropyne is substantially limited.
1. A method of converting a first reaction stream comprising at least one pentafluoropropene to final product streams comprising at least one tetrafluoropropene, comprising the steps of:
(a) reacting said first reaction stream with hydrogen in the presence of a hydrogenation catalyst to obtain a first product stream comprising at least one pentafluoropropane and at least one compound of formula (I):
CH 2 XCHZCF 3 (I)
wherein X and Z are each independently H or F, with the proviso that X and Z are not the same;
(b) separating said at least one compound of formula (I) from said first product stream to obtain a separated product stream (i) and a second reaction stream (ii), wherein (i) comprises a higher weight percent of said at least one compound of formula (I) than (ii); and separately processing (i) and (ii) into final product streams by
(c) reacting said second reaction stream (ii) under dehydrofluorination reaction conditions effective to produce at least one compound of formula (II):
CHX═CZCF 3 (II)
wherein X and Z are each independently H or F, with the proviso that X and Z are not the same; and
(d) reacting said separated product stream (i) containing at least one compound of formula (I) with a dehydrogenation catalyst or combination of dehydrogenation catalysts under conditions effective to produce at least one compound of formula (II);
wherein the reaction conditions are effective to substantially limit the concentration of 3,3,3-trifluoropropyne formed in said final product streams.
2. The method of claim 1 , wherein the reaction conditions are effective to substantially limit the concentration of 3,3,3-trifluoropropyne formed in said final product streams to less than about 100 parts per million.
3. The method of claim 1 , wherein the reaction conditions are effective to substantially limit the concentration of 3,3,3-trifluoropropyne formed in said final product streams to less than about 50 parts per million.
4. The method of claim 1 , wherein the reaction conditions are effective to substantially limit the concentration of 3,3,3-trifluoropropyne formed in said final product streams to less than about 20 parts per million.
5. The method of claim 1 wherein step (d) further comprises exposing separated product stream (i) to one or more oxidants.
6. The method of claim 5 wherein said one or more oxidants are selected from the group consisting of O 2 , CO 2 , N 2 O and mixtures of two or more thereof.
7. The method of claim 1 wherein said dehydrogenation catalyst comprises one or more Group VIII noble metals supported on a metal oxyfluoride support.
8. The method of claim 7 wherein said one or more Group VIII noble metals is selected from the group consisting of Pt, Rh, Ru, Pd, and mixtures thereof.
9. The method of claim 7 wherein said metal oxyfluoride support is selected from the group consisting of oxyfluorides of Zr, Al, Ga, Cr, La, Y, Fe, Mg, and mixtures thereof.
10. The method of claim 1 wherein said dehydrogenation catalyst comprises a metal oxyfluoride catalyst.
11. The method of claim 10 wherein said metal oxyfluoride catalyst is selected from the group consisting of oxyfluorides of Ni, Co, Mg, Al, Ga, Cr, La, Y, Fe, Zr, and mixtures thereof.