# US 11,028,029 B2 · Process for the production of 2,3,3,3-tetrafluoropropene

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- Number: US 11,028,029 B2
- Document ID: US11028029B2
- Status: Granted
- Kind: B2
- Application number: 16/758,097
- Filed: 2018-11-08
- Published: 2020-10-22
- Granted: 2021-06-08
- Earliest claimed: 2017-11-13
- Assignees: Arkema France
- Applicants: Arkema France
- Inventors: Bertrand Collier; Dominique Deur-Bert; Anne Pigamo; Laurent Wendlinger
- Web page: https://patentgrep.com/patent/US11028029B2

## CPC

- C07C 17/25: by splitting-off hydrogen halides from halogenated hydrocarbons
- B01J 23/26: Chromium
- C07C 17/206: {the other compound being HX}
- C07C 21/18: containing fluorine
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS

## Abstract

The present invention relates to a process for the production of 2,3,3,3-tetrafluoropropene comprising the stages: i) in a first reactor, bringing 2-chloro-3,3,3-trifluoropropene into contact with hydrofluoric acid in the gas phase in the presence of a catalyst, in order to produce a stream A comprising 2,3,3,3-tetrafluoropropene, HF and unreacted 2-chloro-3,3,3-trifluoropropene; and ii) in a second reactor, bringing hydrofluoric acid into contact, in the gas phase in the presence or absence of a catalyst, with at least one chlorinated compound selected from the group consisting of 1,1,1,2,3-pentachloropropane, 2,3-dichloro-1,1,1-trifluoropropane, 2,3,3,3-tetrachloropropene and 1,1,2,3-tetrachloropropene, in order to produce a stream B comprising 2-chloro-3,3,3-trifluoropropene, characterized in that the stream A obtained in stage i) feeds said second reactor used for stage ii); and in that the pressure at the inlet of said first reactor of stage i) is greater than the pressure at the inlet of said second reactor of stage ii).

## Claims

### Claim 1

A process for the production of 2,3,3,3-tetrafluoropropene comprising the stages:
i. in a first reactor, bringing 2-chloro-3,3,3-trifluoropropene into contact with hydrofluoric acid in the gas phase in the presence of a catalyst, in order to produce a stream A comprising 2,3,3,3-tetrafluoropropene, HF and unreacted 2-chloro-3,3,3-trifluoropropene; and
ii. in a second reactor, bringing hydrofluoric acid into contact, in the gas phase in the presence or absence of a catalyst, with at least one chlorinated compound selected from the group consisting of 1,1,1,2,3-pentachloropropane, 2,3-dichloro-1,1,1-trifluoropropane, 2,3,3,3-tetrachloropropene and 1,1,2,3-tetrachloropropene, in order to produce a stream B comprising 2-chloro-3,3,3-trifluoropropene,
wherein the stream A obtained in stage i) feeds said second reactor used for stage ii); and the pressure at the inlet of said first reactor of stage i) is greater than the pressure at the inlet of said second reactor of stage ii).

### Claim 2 (depends on 1)

The process as claimed in claim 1, wherein the pressure difference between the pressure at the inlet of said first reactor and the pressure at the inlet of said second reactor is from 100 mbar to 3.5 bar.

### Claim 3 (depends on 1)

The process as claimed claim 1, wherein stage i) and stage ii) are carried out in the presence of a catalyst.

### Claim 4 (depends on 3)

The process as claimed in claim 3, wherein the catalyst is based on chromium and also comprises a co-catalyst selected from the group consisting of Ni, Zn, Co, Mn and Mg.

### Claim 5 (depends on 1)

The process as claimed in claim 1, wherein the stream B also comprises 2,3,3,3-tetrafluoropropene, HF, HCl and 1,1,1,2,2-pentafluoropropane.

### Claim 6 (depends on 1)

The process as claimed in claim 1, wherein the stream B is purified in order to form a first stream comprising 2,3,3,3-tetrafluoropropene, HCl and 1,1,1,2,2-pentafluoropropane and a second stream comprising HF and 2-chloro-3,3,3-trifluoropropene.

### Claim 7 (depends on 6)

The process as claimed in claim 6, wherein said second stream is recycled in stage i).

### Claim 8 (depends on 1)

The process as claimed in claim 1, wherein said stream A and said at least one chlorinated compound are brought into contact prior to the entry of these into said second reactor.

### Claim 9 (depends on 1)

The process as claimed in claim 1, wherein the temperature at which stage i) is carried out is different from that at which stage ii) is carried out; and the difference between the temperature at which stage i) is carried out and the temperature at which stage ii) is carried out is greater than 0.2° C. and less than 60° C.

### Claim 10 (depends on 1)

The process as claimed in claim 1, wherein the stream B is cooled to a temperature of less than 100° C., then distilled in order to form a first stream comprising 2,3,3,3-tetrafluoropropene, HCl and 1,1,1,2,2-pentafluoropropane, and a second stream comprising HF and 2-chloro-3,3,3-trifluoropropene and possibly 1,2-dichloro-3,3,3-trifluoropropene; the temperature at the distillation column top is from −35° C. to 10° C. and the distillation is carried out at a pressure from 2 to 6 bara; said second stream obtained at the distillation column bottom is recycled in stage i).

### Claim 11 (depends on 3)

The process as claimed in claim 3, wherein the catalyst is a chromium-based catalyst comprising a chromium oxyfluoride, a chromium oxide, a chromium fluoride or a mixture of these.