Process of making fluoroolefins by thermal decomposition of fluorinated ionomers

Patent metadata

Field	Value
Publication number	US-12286387-B2
Application number	US-202017777837-A
Country	US
Kind code	B2
Filing date	Dec 17, 2020
Priority date	Dec 23, 2019
Publication date	Apr 29, 2025
Grant date	Apr 29, 2025

Abstract

The process produces a fluorinated olefin from a fluorinated copolymer having at least one of sulfonic acid groups, carboxylic acid groups, or salts thereof. The process includes heating the fluorinated copolymer at a first temperature not more than 450° C. to decompose at least one of the sulfonic acid groups, carboxylic acid groups, or salts thereof to form a partially pyrolyzed intermediate and subsequently heating the partially pyrolyzed intermediate at a second temperature of at least 550° C. to produce the fluorinated olefin.

First claim

What is claimed is:

1. A process for producing a fluorinated olefin from a fluorinated copolymer comprising at least one of sulfonic acid groups, carboxylic acid groups, or salts thereof, the process comprising:
heating the fluorinated copolymer at a first temperature not more than 450° C. to decompose the at least one of sulfonic acid groups, carboxylic acid groups, or salts thereof to form a partially pyrolyzed intermediate; and
subsequently heating the partially pyrolyzed intermediate at a second temperature of at least 550° C. to produce the fluorinated olefin.

2. The process of claim 1 , wherein the first temperature is in a range from 300° C. to 450° C., and wherein the second temperature is in a range from 600° C. to 700° C.

3. The process of claim 1 , wherein the fluorinated copolymer comprises at least one of the sulfonic acid groups or carboxylic acid groups.

4. The process of claim 1 , wherein the fluorinated copolymercomprises:
divalent units represented by formula —[CF 2 -CF 2 ]—; and
divalent units independently represented by formula:

or combination thereof,
wherein a and p are each independently 0 to 2, each b and q is independently 2 to 8, each c and r is independently 0 to 2, each e and s is independently 1 to 8, and Z and Z′ are each independently a hydrogen, an alkali-metal cation, or a quaternary ammonium cation.

5. The process of claim 4 , wherein Z and Z′ are each hydrogen.

6. The process of claim 5 , further comprising combining the fluorinated copolymer with an inorganic acid.

7. The process of claim 4 , wherein the fluorinated copolymer comprises divalent units represented by formula

wherein a is 0 or 1, b is 2 or 3, c is 0 or 1, and e is 2 to 4.

8. The process of claim 4 , wherein the fluorinated copolymer further comprises at least one divalent unit represented by formula

wherein Rf is a linear or branched perfluoroalkyl group having from 1 to 8 carbon atoms and optionally interrupted by one or more —O— groups, z is 0, 1, or 2, each n is independently 1, 2, 3, or 4, and m is 0, 1, or 2.

9. The process of claim 1 , wherein the copolymer has an —-SO 3 Z or —CO 2 Z′ equivalent weight in a range from 500 to 2000, wherein Z and Z′ are each independently a hydrogen, an alkali-metal cation, or a quaternary ammonium cation.

10. The process of claim 1 , wherein the fluorinated olefin comprises at least one of tetrafluoroethylene or hexafluoropropylene.

11. The process of claim 1 , wherein at least one of heating or subsequently heating is carried out at least partially with microwave radiation.

12. The process of claim 11 , wherein at least one of the fluorinated copolymer or the partially pyrolyzed intermediate is contacted by microwave active particles.

13. The process of claim 1 , wherein the fluorinated copolymer is a component of a device comprising at least one of a catalyst ink, a polymer electrolyte membrane, a catalyst layer, a gas diffusion layer, a bipolar plate, or an electrolysis cell.

14. The process of claim 13 , further comprising at least one crushing or shredding the device and heating the device while simultaneously heating the fluorinated copolymer.

15. The process of claim 13 , further comprising recovering a metal after producing the fluorinated olefin.

16. The process of claim 15 , wherein the metal comprises at least one of gold, silver, platinum, or palladium.

17. The process of claim 1 , wherein at least one of heating or subsequently heating is carried out in a fluidized bed reactor, agitated reactor, or rotary kiln.

18. The process of claim 1 , wherein at least one of heating or subsequently heating is carried out in the presence of a carrier gas comprising at least one of nitrogen, steam, or a noble gas.

Assignees

• 3M Innovative Properties Company

Inventors

• Thaler Arne
• Schmidt-Rodenkirchen Achim
• Muggli Mark W
• Mierdel Konstantin
• Hintzer Klaus
• Gerdes Thorsten
• Duchesne Denis
• Dahlke Gregg D

Classifications

• Y02E60/50

  Fuel cells · CPC title

• C07C17/367 Primary

  by depolymerisation · CPC title