Catalytic gas phase fluorination
View Patent ↗The present invention relates to a fluorination process, comprising: an activation stage comprising contacting a fluorination catalyst with an oxidizing agent-containing gas flow for at least one hour; and at least one reaction stage comprising reacting a chlorinated compound with hydrogen fluoride in gas phase in the presence of the fluorination catalyst, so as to produce a fluorinated compound.
1. A fluorination process, comprising:
an activation stage comprising three successive steps:
1) contacting a fluorination catalyst with hydrogen fluoride;
2) reacting a chlorinated compound with hydrogen fluoride in the gas phase in the presence of the fluorination catalyst; and
3) contacting the fluorination catalyst with an oxidizing agent-containing gas flow that does not contain HF for at least one hour; and
at least one reaction stage comprising reacting the chlorinated compound with hydrogen fluoride in the gas phase in the presence of the activated fluorination catalyst, so as to produce a fluorinated compound; wherein the activation stage and the reaction stage take place in a single reactor.
2. The process of claim 1 , further comprising a plurality of reaction stages alternating with a plurality of regeneration stages, wherein the plurality of reaction stages comprise reacting the chlorinated compound with hydrogen fluoride in gas phase in the presence of the fluorination catalyst, and the plurality of regeneration stages comprise contacting the fluorination catalyst with an oxidizing agent-containing gas flow.
3. The process of claim 2 , wherein the oxidizing agent-containing gas flow of the activation stage and/or the regeneration stages is an oxygen-containing gas flow.
4. The process of claim 2 , wherein the activation stage and/or the regeneration stages comprise contacting the fluorination catalyst with the oxidizing agent-containing gas flow for at least 2 hours.
5. The process of claim 2 , wherein the oxidizing agent-containing gas flow of the regeneration stages 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 stages is preferably from 2 to 98 mol % relative to the total amount of oxidizing agent and hydrogen fluoride.
6. The process of claim 2 , wherein the oxidizing agent-containing gas flow of the regeneration stages does not contain hydrogen fluoride.
7. The process of claim 6 , wherein the oxidizing agent-containing gas flow of the activation stage and/or the regeneration stages is air.
8. The process of claim 2 , 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.
9. The process of claim 2 , wherein the oxidizing agent-containing gas flow is contacted with the fluorination catalyst during the activation stage and/or the regeneration stages 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 in the at least one reaction stage, the chlorinated compound is 2-chloro-3,3,3-trifluoro-1-propene and 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 11 , 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, the ratio of oxygen being from 0.05 to 15 mole %, with respect to the total amount of chlorinated compound and oxygen.
21. The fluorination process of claim 1 , wherein steps 2 and 3 of the activation stage are repeated.