Catalytic gas phase fluorination
View Patent ↗The invention relates to a fluorination process, alternately comprising reaction stages and regeneration stages, wherein the reaction stages comprise reacting a chlorinated compound with hydrogen fluoride in gas phase in the presence of a fluorination catalyst to produce a fluorinated compound, and the regeneration stages comprise contacting the fluorination catalyst with an oxidizing agent-containing gas flow.
1. A fluorination process, comprising a preliminary activation stage which comprises contacting a fluorination catalyst with an oxidizing agent-containing gas flow that does not contain hydrogen fluoride, alternately comprising reaction stages and regeneration stages, wherein the reaction stages comprise reacting a chlorinated compound with hydrogen fluoride in gas phase in the presence of a fluorination catalyst to produce a fluorinated compound, and the regeneration stages comprise contacting the fluorination catalyst with an oxidizing agent-containing gas flow, wherein the alternation between the reaction stages and regeneration stages is regulated in a pre-determined, fixed manner, and wherein the preliminary activation stage, the reaction stages and the regeneration stages take place in a single reactor.
2. The process of claim 1 , wherein the oxidizing agent-containing gas flow of the regeneration stage is an oxygen-containing gas flow.
3. The process of claim 1 , wherein the regeneration stage comprises contacting the fluorination catalyst with the oxidizing agent-containing gas flow for at least 2 hours.
4. The process of claim 1 , wherein the oxidizing agent-containing gas flow of the regeneration stage contains hydrogen fluoride in addition to the oxidizing agent, and wherein the proportion of oxidizing agent in the oxidizing agent-containing gas flow of the regeneration stage is from 2 to 98 mol %, relative to the total amount oxidizing agent and hydrogen fluoride.
5. The process of claim 1 , wherein the oxidizing agent-containing gas flow of the regeneration stage does not contain hydrogen fluoride.
6. The process of claim 5 , wherein the oxidizing agent-containing gas flow of the regeneration stage is air.
7. The process of claim 1 , wherein the regeneration stage comprises contacting the fluorination catalyst with a hydrogen fluoride gas flow, either:
before contacting the fluorination catalyst with the oxidizing agent-containing gas flow; or
after contacting the fluorination catalyst with the oxidizing agent-containing gas flow.
8. The process of claim 1 , wherein the activation stage comprises a preliminary step of reacting the chlorinated compound with hydrogen fluoride in gas phase in the presence of the fluorination catalyst, prior to contacting the chlorinated compound with the oxidizing agent-containing gas flow.
9. The process of claim 1 , wherein the oxidizing agent-containing gas flow is contacted with the fluorination catalyst during the regeneration stage at a temperature of from 250 to 500° C.
10. The process of claim 1 , wherein the fluorinated compound is a fluoroolefin.
11. The process of claim 1 , wherein the chlorinated compound is selected from the group consisting of hydrochlorocarbons, hydrochlorofluorocarbons and hydrochlorofluoroolefins.
12. The process of claim 1 , wherein the fluorination catalyst is supported on a support comprising fluorinated alumina, fluorinated chromia, fluorinated activated carbon or graphite carbon.
13. The process of claim 1 , wherein the fluorination catalyst is an unsupported catalyst.
14. The process of claim 1 , wherein the fluorination catalyst further comprises a co-catalyst comprising Co, Zn, Mn, Mg, V, Mo, Te, Nb, Sb, Ta, P, Ni or mixtures thereof, and wherein said co-catalyst is present in an amount from about 1-10 wt % of said fluorination catalyst.
15. The process of claim 1 , wherein the fluorination catalyst is a mixed chromium/nickel catalyst, the atomic ratio of nickel to chromium being from 0.5 to 2.
16. The process of claim 1 , wherein the chlorinated compound is 2-chloro-3,3,3-trifluoro-1-propene, and wherein the molar ratio of hydrogen fluoride to 2-chloro-3,3,3-trifluoro-1-propene is from 3:1 to 150:1.
17. The process of claim 1 , wherein the reaction stages are carried out at a pressure of from 1 to 20 bars.
18. The process of claim 1 , wherein the reaction stages are carried out at a temperature of from 200 to 450° C.
19. The process of claim 1 , wherein the contact time between hydrogen fluoride and the chlorinated compound during the reaction stages is from 6 to 100 s.
20. The process of claim 1 , wherein the reaction stages are carried out in the presence of oxygen as the oxidizing agent, the ratio of oxygen being from 0.05 to 15 mole %, with respect to the total amount of chlorinated compound and oxygen.