# US 5,705,718 A · Process for the purification of 1,1,1,2-tetrafluoroethane

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- Number: US 5,705,718 A
- Document ID: US5705718A
- Status: Granted
- Kind: A
- Application number: 08/730,738
- Filed: 1996-10-15
- Granted: 1998-01-06
- Earliest claimed: 1993-10-13
- Assignees: Elf Atochem S.A.
- Inventors: Bernard Cheminal; Andre Lantz
- Web page: https://patentgrep.com/patent/US5705718A

## CPC

- C07C 17/395: by treatment giving rise to a chemical modification of at least one compound
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS

## Abstract

To remove the unsaturated impurities (in particular 1-chloro-2,2-difluoroethylene and polyfluoropropenes) present in crude 1,1,1,2-tetrafluoroethane (F134a), a gaseous mixture of crude F134a, of hydrofluoric acid and of chlorine is treated in gaseous phase in the presence of a fluorination catalyst at a temperature of between 100.degree. and 300.degree. C. and at a pressure between atmospheric pressure and 2.5 MPa, the molar ratio HF/F134a being between 0.05 and 0.5 and the molar ratio Cl.sub.2 /F134a between 0.0001 and 0.1.

## Claims

### Claim 1

Process for the purification of a crude 1,1,1,2-tetrafluoroethane (F134a) containing unsaturated impurities, comprising treating a gaseous mixture of crude 1,1,1,2-tetrafluoroethane, of hydroluoric acid and of chlorine in gaseous phase at a temperature of between 150.degree. and 275.degree. C. and at a pressure ranging from atmospheric pressure up to 2.5 MPa, in the presence of a fluorination catalyst, the molar ratio HF/F134a being between 0.05 and 0.5 and the molar ratio Cl.sub.2 /F134a being between 0.0001 and 0.1.

### Claim 2 (depends on 1)

Process according to claim 1, wherein the unsaturated impurities are 1-chloro-2,2-difluoroethylene and/or (chloro) fluorinated C.sub.3 or C.sub.4 olefins.

### Claim 3 (depends on 1)

Process according to claim 1, wherein the operation is carried out at a pressure between atmospheric pressure and 1.5 MPa.

### Claim 4 (depends on 1)

Process according to claim 1, wherein the contact time is between 10 and 200 seconds.

### Claim 5 (depends on 4)

Process according to claim 4, wherein the contact time is between 20 and 100 seconds.

### Claim 6 (depends on 1)

Process according to claim 1, wherein the molar ratio HF/F134a is between 0.125 and 0.300.

### Claim 7 (depends on 1)

Process according to claim 1, wherein the molar ratio Cl.sub.2 /F134a is between 0.001 and 0.03.

### Claim 8 (depends on 1)

Process according to claim 1, wherein the fluorination catalyst is a bulk or supported catalyst further based on chromium, iron, manganese, cobalt and/or zinc.

### Claim 9 (depends on 8)

Process according to claim 8, wherein a bulk chromium oxide is used as catalyst.

### Claim 10 (depends on 1)

Process according to claim 1, wherein a nickel fluoride supported on fluorinated alumina is used as catalyst.

### Claim 11 (depends on 1)

Process according to claim 1, wherein a catalyst based on nickel fluoride and on chromium oxide supported on aluminium fluoride is used.

### Claim 12 (depends on 1)

Process according to claim 1, wherein the temperature is between 150.degree. and 225.degree. C.

### Claim 13

Process for the purification of a crude 1,1,1,2-tetrafluoroethane (F134a) containing unsaturated impurities, comprising treating a gaseous mixture of crude 1,1,1,2-tetrafluoroethane, of hydrofluoric acid and of chlorine in gaseous phase at a temperature of between 100.degree. and 300.degree. C. and at a pressure ranging from atmospheric pressure up to 2.5 MPa, in the presence of a fluorination catalyst based on nickel, the molar ratio HF/F134a being between 0.05 and 0.5 and the molar ratio Cl.sub.2 /F134a being between 0.0001 and 0.1.

### Claim 14

Process for the purification of a crude 1,1,1,2-tetrafluoroethane (F134a) containing unsaturated impurities, comprising treating a gaseous mixture of crude 1,1,1,2-tetrafluoroethane, of hydrofluoric acid and of chlorine in gaseous phase at a temperature of between 100.degree. and 300.degree. C. and at a pressure ranging from atmospheric pressure up to 2.5 MPa, in the presence of a fluorination catalyst based on iron, manganese, cobalt and/or zinc, the molar ratio HF/F134a being between 0.05 and 0.5 and the molar ratio Cl.sub.2 /F134a being between 0.0001 and 0.1.