Recovery of branched fluorinated emulsifiers

Patent metadata

Field	Value
Publication number	US-9694333-B2
Application number	US-201515302525-A
Country	US
Kind code	B2
Filing date	Apr 15, 2015
Priority date	Apr 18, 2014
Publication date	Jul 4, 2017
Grant date	Jul 4, 2017

Abstract

Described herein is a process for recovering a branched, ether-containing fluorinated emulsifier from an anion exchange resin by (1) contacting the anion exchange resin with a recovery fluid to form an eluate, the recovery fluid comprising an ammonium salt, water, and a water-miscible solvent, wherein the fluorinated emulsifier is of the formula: [Rf-(0-R′f)n-0-CF(CF3)-C(0)0-]i M+1; and (2) separating the anion exchange resin from the eluate.

First claim

What is claimed is:

1. A process for recovering a fluorinated emulsifier from an anion exchange resin, comprising
contacting the anion exchange resin with a recovery fluid to form an eluate, the recovery fluid comprising an ammonium salt, water, and a water-miscible solvent, wherein the fluorinated emulsifier is of the formula:
[Rf—(O—R′f) n —O—CF(CF 3 )—C(O)O − ] i M +i

 wherein Rf is a fluorinated alkyl group comprising 1 to 5 carbon atoms; R′f is a divalent fluorinated group comprising 1 to 5 carbon atoms; n is 0, 1, 2, or 3; and M +i represents a cation having the valance i and i is 1, 2 or 3; and

separating the anion exchange resin from the eluate.

2. The process of claim 1 , wherein the fluorinated emulsifier is selected from at least one of: (i) n=0 and Rf═CF 3 (CF 2 ) 2 —; and (ii) n=1 and Rf═CF 3 — and R′f=—CF(CF 3 )CF 2 —.

3. The process of claim 1 , wherein the ammonium salt is of the formula:
(NR 4 ) n X
wherein each R is independently selected from H and an alkyl group comprising 1-5 carbon atoms; n is 1 or 2; and X is selected from F, Cl, Br, I, and an anionic organic residue.

4. The process of claim 1 , wherein the water-miscible solvent is an aliphatic alcohol having between 1-5 carbon atoms.

5. The process of claim 1 , wherein the recovery fluid is substantially free of a strong acid.

6. The process of claim 1 , wherein the recovery fluid has a pH greater than 6.

7. The process of claim 1 , wherein an amount of the ammonium salt is 0.2 to 5 wt % as compared to the total weight of the recovery fluid.

8. The process of claim 1 , wherein the contacting is conducted at a temperature of 20 to 80° C.

9. The process of claim 1 , wherein the % wt of the water-miscible solvent to the total weight of the recovery fluid is 50 wt % to 99 wt %.

10. The process of claim 1 , further comprising: removing the water and water-miscible solvent from the eluate to provide a concentrate; acidifying the concentrate to generate the free acid form of the fluorinated emulsifier; and distilling the free acid form of the fluorinated emulsifier.

11. The process of claim 1 , further comprising distilling eluate, concentrate, and/or the free acid form of the fluorinated emulsifier.

12. The process of claim 1 , further comprising regenerating the fluorinated emulsifier back to its original form.

13. The process of claim 1 , further comprising removing the water and water-miscible solvent from the eluate to provide a concentrate.

Assignees

• 3M Innovative Properties Co

Inventors

• Hintzer Klaus
• Obermaier Egon
• Thaler Arne

Classifications

• B01F17/0035 Primary

  Operations & Transport · mapped topic

• B01J41/12

  Macromolecular compounds · CPC title

• B01J41/05

  in the strongly basic form · CPC title

• B01J49/57

  for anionic exchangers · CPC title

• B01J49/07 Primary

  containing anionic exchangers · CPC title