Process for the manufacture of hydrofluoroolefins
In this invention we are disclosing a process for the synthesis of hydrocchlorofluoro olefins (HCFO) and/or hydrofluoroolefins (HFO). The process is based on the steps of fluorination of hydrochloropropenes or hydrochloropropanes to form hydrochlorofluoropropenes and/or hydrofluoropropenes, followed by gas phase, catalytic fluorination of the hydrochlorofluoropropenes to form hydrofluoropropenes.
1. A process for producing 1,1,1,2-tetrafluoropropene, comprising the steps of:
a) fluorinating tetrachloropropene to form 2-chloro-3,3,3-trifluoropropene and HCl and first co-products in the presence of a catalyst selected from the group consisting of homogeneous fluorination catalyst selected from the group consisting of SbCl 5 , TiCl 4 , SnCl 4 and heterogenous catalyst comprising a supported or unsupported chromium catalyst, said heterogenous catalyst optionally further comprising a co-catalyst selected from the group consisting of nickel, zinc, cobalt and magnesium and thereafter
b) fluorinating said 2-chloro-3,3,3-tri-fluoropropene, in a gas phase, in the presence of a catalyst selected from the group consisting of supported chromium catalyst, unsupported chromium catalyst and mixtures thereof said chromium catalyst optionally further comprising a co-catalyst selected from the group consisting of nickel, cobalt and magnesium, to form 1,1,1,2-tetrafluoropropene and second co-products.
2. The process of claim 1 wherein the step a) of fluorinating a tetrachloropropene comprises contacting the tetrachloropropene with hydrogen fluoride in the gas phase or the liquid phase.
3. The process of claim 1 further comprising the step of separating HCl from said 2-chloro-3,3,3-tri-fluoropropene and HCl and first co-products prior to fluorinating the 2-chloro-3,3 3-tri-fluoropropene.
4. The process of claim 1 wherein said first co-products comprise pentafluoropropane and chlorotetrafluoropropane.
5. The process of claim 4 wherein said pentafluoropropane comprises 1,1,1,2,2-pentafluoropropane and said chlorotetrafluoropropane comprises 1,1,1,2-tetrafluoro-2-chloropropane.
6. The process of claim 1 further comprising the step of separating said second co-products from said 1,1,1,2-tetrafluoropropene.
7. The process of claim 6 further comprising the step of recycling said separated second co-products to step b.
8. The process of claim 1 wherein said second co-products comprise pentafluoropropane and chlorotetrafluoropropane.
9. The process of claim 8 wherein said pentafluoropropane comprises 1,1,1,2,2-pentafluoropropane and said chlorotetrafluoropropane comprises 1,1,1,2-tetrafluoro-2-chloropropane.
10. The process of claim 2 wherein the ratio of tetrachloropropene to hydrogen fluoride ranges from about 1 to 3 to about 1 to 500.
11. The process of claim 1 wherein the ratio of tetrachloropropene to hydrogen fluoride ranges from about 1 to 10 to about 1 to 200.
12. The process of claim 1 wherein the step of fluorinating the 2-chloro-3,3,3-tri-fluoropropene in a gas phase, in the presence of a catalyst comprises contacting said 2-chloro-3,3,3-tri-fluoropropene with hydrogen fluoride.
13. The process of claim 1 wherein said catalyst is activated prior to use.
14. The process of claim 13 wherein said catalyst is activated at a temperature between 200° and 400° C. in a two step process comprising first contacting with HF followed by contacting with air to produce catalyst of the formula such as CrO m F n , with 1.5<m<3 and 0<n<3.
15. The process of claim 1 wherein said tetrachloropropene is prepared via gas phase fluorination of one or more pentachloropropanes.
16. The process of claim 1 wherein said step of fluorinating tetrachloropropene is carried out in the liquid phase in the presence of a homogenous catalyst.
17. The process of claim 1 wherein said step of fluorinating said tetrachloropropene is carried out in the gas phase in the presence of a heterogenous catalyst.
18. The process of claim 1 wherein said tetrachloropropene is selected from the group consisting of 1,1,1,2-tetrachloropropene, 1,1,2,3-tetrachloropropene and mixtures thereof.
19. The process of claim 18 further comprising the step of isomerizing 1,1,1,2-tetrachloropropene, in the presence of an acid catalyst, to produce 1,1,2,3-tetrachloropropene.