Methods for removal of sulfur dioxide (SO2) from trifluoroacetyl chloride (TFAC)

Patent metadata

Field	Value
Publication number	US-11987553-B2
Application number	US-202117466704-A
Country	US
Kind code	B2
Filing date	Sep 3, 2021
Priority date	Sep 11, 2020
Publication date	May 21, 2024
Grant date	May 21, 2024

Abstract

Impurities such as sulfur dioxide (SO 2 ) are removed from trifluoroacetyl chloride (TFAC) through distillation, adsorption, or a combination thereof, and/or including the formation of an azeotrope or azeotrope-like composition including effective amounts of sulfur dioxide (SO 2 ) and trifluoroacetyl chloride (TFAC). The trifluoroacetyl chloride (TFAC) thus purified may then be used in the manufacture of trifluoroiodomethane (CF 3 I). Also disclosed are azeotropes and azeotrope like compositions of sulfur dioxide (SO 2 ) and trifluoroacetyl chloride (TFAC).

First claim

The invention claimed is:

1. A method for removing sulfur dioxide (SO 2 ) from trifluoroacetyl chloride (TFAC), comprising the steps of:
conveying a feed stream to a distillation column, the feed stream comprising trifluoroacetyl chloride (TFAC) and sulfur dioxide (SO 2 );
forming an azeotrope or azeotrope-like composition consisting essentially of effective amounts of trifluoroacetyl chloride (TFAC) and sulfur dioxide (SO 2 );
collecting the distillate from the distillation column, the distillate comprising the azeotrope or azeotrope-like composition; and
collecting a bottoms product from the distillation column, the bottoms product consisting essentially of trifluoroacetyl chloride (TFAC).

2. A method for removing sulfur dioxide (SO 2 ) from trifluoroacetyl chloride (TFAC), comprising the steps of:
conveying a feed stream to a distillation column, the feed stream comprising trifluoroacetyl chloride (TFAC), and sulfur dioxide (SO 2 );
forming an azeotrope or azeotrope-like composition consisting essentially of effective amounts of trifluoroacetyl chloride (TFAC) and sulfur dioxide (SO 2 );
collecting the distillate from the distillation column, the distillate comprising the azeotrope or azeotrope-like composition;
collecting a bottoms product from the distillation column;
contacting the bottoms product from the distillation column with a solid adsorbent; and
collecting a product stream consisting essentially of trifluoroacetyl chloride (TFAC).

3. The method of claim 1 , further comprising the steps of:
contacting the distillate with a solid adsorbent; and
collecting a product stream consisting essentially of trifluoroacetyl chloride (TFAC).

4. The method of claim 1 , further comprising the steps of:
contacting the bottoms product from the distillation column with a first solid adsorbent;
collecting a product stream consisting essentially of trifluoroacetyl chloride (TFAC);
contacting the distillate from the distillation column with a second solid adsorbent; and
collecting a product stream consisting essentially of trifluoroacetyl chloride (TFAC).

5. The method of claim 1 , further comprising, prior to the conveying step, the steps of:
contacting a feed stream with a first solid adsorbent, the feed stream comprising trifluoroacetyl chloride (TFAC) and sulfur dioxide (SO 2 ); and
collecting a product stream comprising trifluoroacetyl chloride (TFAC) and sulfur dioxide (SO 2 ).

6. The method of claim 5 , wherein the bottoms product includes sulfur dioxide (SO 2 ) in an amount of about 100 ppm or less.

7. The method of claim 1 , wherein the azeotrope or azeotrope-like composition comprises from about 25 wt. % to about 99 wt. % of trifluoroacetyl chloride (TFAC) and from about 1 wt. % to about 75 wt. % of sulfur dioxide (SO 2 ).

8. The method of claim 1 , wherein the bottoms product includes sulfur dioxide (SO 2 ) in an amount of about 100 ppm or less.

9. The method of claim 3 , wherein the bottoms product includes sulfur dioxide (SO 2 ) in an amount of about 100 ppm or less.

10. The method of claim 4 , wherein the bottoms product includes sulfur dioxide (SO 2 ) in an amount of about 100 ppm or less.

11. The method of claim 2 , wherein the azeotrope or azeotrope-like composition comprises from about 25 wt. % to about 99 wt. % of trifluoroacetyl chloride (TFAC) and from about 1 wt. % to about 75 wt. % of sulfur dioxide (SO 2 ).

12. The method of claim 2 , further comprising the steps of:
contacting the distillate with a solid adsorbent; and
collecting a product stream consisting essentially of trifluoroacetyl chloride (TFAC).

13. The method of claim 12 , wherein the bottoms product includes sulfur dioxide (SO 2 ) in an amount of about 100 ppm or less.

14. The method of claim 2 , further comprising the steps of:
contacting the bottoms product from the distillation column with a first solid adsorbent;
collecting a product stream consisting essentially of trifluoroacetyl chloride (TFAC);
contacting the distillate from the distillation column with a second solid adsorbent; and
collecting a product stream consisting essentially of trifluoroacetyl chloride (TFAC).

15. The method of claim 14 , wherein the bottoms product includes sulfur dioxide (SO 2 ) in an amount of about 100 ppm or less.

16. The method of claim 2 , further comprising, prior to the conveying step, the steps of:
contacting a feed stream with a first solid adsorbent, the feed stream comprising trifluoroacetyl chloride (TFAC) and sulfur dioxide (SO 2 ); and
collecting a product stream comprising trifluoroacetyl chloride (TFAC) and sulfur dioxide (SO 2 ).

17. The method of claim 16 , wherein the bottoms product includes sulfur dioxide (SO 2 ) in an amount of about 100 ppm or less.

18. The method of claim 2 , wherein the solid adsorbent comprises one or more of carbon molecular sieves, zeolite powder, silica gel, activated alumina, activated carbon, and combinations of the foregoing.

19. The method of claim 18 , wherein the solid adsorbent comprises carbon molecular sieves.

20. The method of claim 3 , wherein the solid adsorbent comprises carbon molecular sieves.

Assignees

• Honeywell Int Inc

Inventors

• Kopkalli Haluk
• Wang Haiyou
• Yang Terris
• Mcclaine Jennifer W
• Wilcox Richard
• Close Joshua
• Mallepally Rajendar

Classifications

• C07C71/00 Primary

  Esters of oxyacids of halogens · CPC title

• B01D3/36 Primary

  Azeotropic distillation · CPC title

• B01D53/02

  by adsorption, e.g. preparative gas chromatography {(solid sorbent compositions B01J20/00, preparation of inorganic compounds or elements C01)} · CPC title

• B01J20/18

  Synthetic zeolitic molecular sieves · CPC title

• C07C51/64 Primary

  Separation; Purification; Stabilisation; Use of additives · CPC title