Process for purifying an ionic liquid

Patent metadata

Field	Value
Publication number	US-10138209-B2
Application number	US-201715486300-A
Country	US
Kind code	B2
Filing date	Apr 13, 2017
Priority date	Jun 14, 2016
Publication date	Nov 27, 2018
Grant date	Nov 27, 2018

Abstract

The invention relates to a process for purifying an ionic liquid comprising dialkylimidazolium ions by means of stripping, wherein water vapor is used at a particular temperature. The process according to the invention is characterized in that the decomposition of the ionic liquid is minimized during the procedure of the process.

First claim

What is claimed is:

1. A process for purifying an ionic liquid of the structure Q + A − , wherein Q + is a 1,3-dialkylimidazolium ion, and wherein A − is selected from the group consisting of: dialkyl phosphate; alkyl sulphate; alkyl sulphonate; alkyl carboxylate; chloride; hydrogen sulphate; dihydrogen phosphate; monoalkyl hydrogen phosphate; and nitrate;
wherein the ionic liquid of the structure Q + A − is subjected to a stripping with water vapour having a temperature of ≤99° C.

2. The process of claim 1 , wherein, in the ionic liquid of the structure Q + A − , Q + is a 1,3-dialkylimidazolium ion, in which the alkyl groups are each independently C 1 -C 10 -alkyl groups, and A − is selected from the group consisting of: dialkyl phosphate, in which the alkyl groups are each independently C 1 -C 10 -alkyl groups; alkyl sulphate, in which the alkyl group is a C 1 -C 10 -alkyl group; alkyl sulphonate, in which the alkyl group is a C 1 -C 10 -alkyl group; alkyl carboxylate, in which the alkyl group is a C 1 -C 10 -alkyl group; chloride; hydrogen sulphate; dihydrogen phosphate; monoalkyl hydrogen phosphate, in which the alkyl group is a C 1 -C 10 -alkyl group; and nitrate.

3. The process of claim 2 , wherein, in the ionic liquid of the structure Q + A − , Q + is a 1,3-dialkylimidazolium ion, in which the alkyl groups are each independently C 1 -C 10 -alkyl groups, and A − is selected from the group consisting of: dialkyl phosphate, in which the alkyl groups are each independently C 1 -C 10 -alkyl groups; alkyl sulphate, in which the alkyl group is a C 1 -C 10 -alkyl group; alkyl sulphonate, in which the alkyl group is a C 1 -C 10 -alkyl group; alkyl carboxylate, in which the alkyl group is a C 1 -C 10 -alkyl group; dihydrogen phosphate; and monoalkyl hydrogen phosphate, in which the alkyl group is a C 1 -C 10 -alkyl group.

4. The process of claim 3 , wherein, in the ionic liquid of the structure Q + A − , Q + is a 1,3-dialkylimidazolium ion, in which the alkyl groups are each independently C 1 -C 10 -alkyl groups, and A − is dialkyl phosphate, in which the alkyl groups are each independently C 1 -C 10 -alkyl groups.

5. The process of claim 4 , wherein Q + is a 1,3-dimethylimidazolium cation or a 1-ethyl-3-methylimidazolium cation.

6. The process of claim 5 , wherein Q + is a 1-ethyl-3-methylimidazolium cation.

7. The process of claim 5 , wherein A − is diethyl phosphate.

8. The process of claim 7 , wherein Q + is a 1-ethyl-3-methylimidazolium cation.

9. The process of claim 1 , wherein the water vapour has a temperature in the range of 10° C. to 90° C.

10. The process of claim 1 , wherein the structure Q + A − has a temperature which is higher than the temperature of the water vapour used.

11. The process of claim 1 , wherein the ionic liquid is passed at least partially over a bed of filling materials or over a structured packing.

12. The process of claim 9 , wherein the structure Q + A − has a temperature which is higher than the temperature of the water vapour used.

13. The process of claim 12 , wherein the ionic liquid is passed at least partially over a bed of filling materials or over a structured packing.

14. The process of claim 13 , wherein, in the ionic liquid of the structure Q + A − , Q + is a 1,3-dialkylimidazolium ion, in which the alkyl groups are each independently C 1 -C 10 -alkyl groups, and A − is selected from the group consisting of: dialkyl phosphate, in which the alkyl groups are each independently C 1 -C 10 -alkyl groups; alkyl sulphate, in which the alkyl group is a C 1 -C 10 -alkyl group; alkyl sulphonate, in which the alkyl group is a C 1 -C 10 -alkyl group; alkyl carboxylate, in which the alkyl group is a C 1 -C 10 -alkyl group; chloride; hydrogen sulphate; dihydrogen phosphate; monoalkyl hydrogen phosphate, in which the alkyl group is a C 1 -C 10 -alkyl group; and nitrate.

15. The process of claim 14 , wherein, in the ionic liquid of the structure Q + A − , Q + is a 1,3-dialkylimidazolium ion, in which the alkyl groups are each independently C 1 -C 10 -alkyl groups, and A − is selected from the group consisting of: dialkyl phosphate, in which the alkyl groups are each independently C 1 -C 10 -alkyl groups; alkyl sulphate, in which the alkyl group is a C 1 -C 10 -alkyl group; alkyl sulphonate, in which the alkyl group is a C 1 -C 10 -alkyl group; alkyl carboxylate, in which the alkyl group is a C 1 -C 10 -alkyl group; dihydrogen phosphate; and monoalkyl hydrogen phosphate, in which the alkyl group is a C 1 -C 10 -alkyl group.

16. The process of claim 15 , wherein, in the ionic liquid of the structure Q + A − , Q + is a 1,3-dialkylimidazolium ion, in which the alkyl groups are each independently C 1 -C 10 -alkyl groups, and A − is dialkyl phosphate, in which the alkyl groups are each independently C 1 -C 10 -alkyl groups.

17. The process of claim 16 , wherein Q + is a 1,3-dimethylimidazolium cation or a 1-ethyl-3-methylimidazolium cation.

18. The process of claim 17 , wherein Q + is a 1-ethyl-3-methylimidazolium cation.

19. The process of claim 17 , wherein A − is diethyl phosphate.

20. The process of claim 19 , wherein Q + is a 1-ethyl-3-methylimidazolium cation.

Assignees

• Evonik Degussa Gmbh

Inventors

• Bahlmann Matthias
• Zehnacker Olivier
• Lütkehaus Markus
• Willy Benjamin
• Escher Werner
• Wang Xinming
• Schneider Rolf
• Hiller Christoph
• Münzner Stefan

Classifications

• C07D233/58 Primary

  with only hydrogen atoms or radicals containing only hydrogen and carbon atoms, attached to ring nitrogen atoms · CPC title

• C07F9/141

  Esters of phosphorous acids · CPC title

• B01D1/14

  with heated gases or vapours {or liquids} in contact with the liquid · CPC title

• C07F9/11

  with hydroxyalkyl compounds without further substituents on alkyl · CPC title