Method for making dimethyl sulfone from dimethyl sulfoxide and hydrogen peroxide

• US 20020004614A1
• Filed: 07/02/2001
• Published: 01/10/2002
• Est. Priority Date: 07/05/2000
• Status: Active Grant

• Current Assignee: Sloss Industries Corporation (New WEI, Inc.)
• Original Assignee: Sloss Industries Corporation (New WEI, Inc.)
• Inventors: Jones, Charles, Friedrich, Joyce D., Alwis, Wima K., Paschal, John C.
• Granted Patent: US 6,552,231 B2
• Time in Patent Office: Days
• US Class Current: 568/28
• CPC Class Codes: C07C 315/02 by formation of sulfone or sulfoxide groups by oxidation of sulfides, or by formation of sulfone groups by oxidation of sulfoxides
• CPC Class Codes: C07C 315/06 Separation; Purification; Stabilisation; Use of additives
• CPC Class Codes: C07C 317/04 of an acyclic saturated carbon skeleton

Abstract

The present invention provides a process for synthesizing dimethyl sulfone by the oxidation of dimethyl sulfoxide with hydrogen peroxide.

Claims

1. A method for making crystalline dimethyl sulfone comprising:

(a) simultaneously adding dimethyl sulfoxide and an aqueous solution of hydrogen peroxide to a preheated, stainless steel reaction vessel precharged with an aqueous solution of dimethyl sulfone at a rate sufficient to maintain the reaction temperature below about 120°

C.;

(b) distilling water from the reaction mixture;

(c) adding water to the reaction mixture to form a dilute reaction solution;

(d) heating and filtering the heated reaction solution;

(e) cooling the reaction solution to crystallize out the dimethyl sulfone; and

(f) filtering or centrifuging the crystallized dimethyl sulfone.

2. The method according to claim 1 wherein the vessel and heel contents are pre-heated to between about 70°

C. and 120°

C.

3. The method according to claim 1 wherein the aqueous hydrogen peroxide solution is at a concentration between 40 and 60%.

4. The method according to claim 1 wherein the molar ratio of hydrogen peroxide to dimethyl sulfoxide is about 1.2.

5. The method according to claim 1 wherein the water distilled from the system during the course of the reaction is approximately 50% of the total system.

6. The method according to claim 1 wherein the water added to the reaction is about equal to the water removed from the reaction by distillation.

7. The method according to claim 1 wherein the reaction solution is cooled to about 2°

C. to 25°

C. to crystallize out the dimethyl sulfone.

8. The method according to claim 7 wherein the reaction solution is cooled to about 5°

C. to crystallize out the dimethyl sulfone.

9. The method according to claim 1 wherein the filtered or centrifuged dimethyl sulfone is washed with ice cold water and dried under vacuum between about 25°

C. and 80°

C.

10. The method according to claim 9 wherein the filtered or centrifuged dimethyl sulfone is washed with ice cold water and dried under vacuum between about 60°

C. and 70°

C.

11. Dimethyl sulfone is prepared as a white, crystalline, pure, free-flowing solid in accordance with the process described in claim 1.

12. A method for making flaked dimethyl sulfone comprising:

(a) simultaneously adding dimethyl sulfoxide and an aqueous solution of hydrogen peroxide to a preheated, stainless steel reaction vessel precharged with an aqueous solution of dimethyl sulfone at a rate sufficient to maintain the reaction temperature below about 120°

C.;

(b) distilling water from the reaction mixture;

(c) cooling the reaction mixture to below 80°

C.;

(d) adjusting the pH of the reaction mixture to about between 8 and 9;

(e) distilling water and forerun from the reaction mixture at atmospheric pressure followed by vacuum of at least 40 mm Hg and then followed by vaccum of 20-30 mm Hg.

(f) distilling the product at about 160-175°

C. as a colorless oil that solidifies upon cooling; and

(g) flaking the product to provide a flowable material.

13. The method according to claim 12 wherein the vessel and heel contents are pre-heated to between about 70°

C. and 120°

C.

14. The method according to claim 12 wherein the aqueous hydrogen peroxide solution is at a concentration between 40 and 60%.

15. The method according to claim 12 wherein the molar ratio of hydrogen peroxide to dimethyl sulfoxide is about 1.2.

16. The method according to claim 12 wherein the water distilled from the system during the course of the reaction is approximately 50% of the total system.

17. The method according to claim 12 wherein the reaction mixture is cooled to below 80°

C.

18. The method according to claim 12 wherein the pH of the reaction mixture is cautiously adjusted to about between 8 and 9 with 10% caustic.

19. The method according to claim 12 wherein water and forerun are distilled from the reaction mixture at atmospheric pressure.

20. The method according to claim 12 wherein vacuum (at least 40 mm Hg, followed by 20-30 mm Hg) is applied to the system.

21. The method according to claim 12 wherein the product is distilled at about 160-175°

C. as a colorless oil that solidifies upon cooling.

22. The method according to claim 12 wherein the purified product is then flaked to produce a flowable material.

23. Dimethyl sulfone is prepared as a white, flaked, pure, free-flowing solid in accordance with the process described in claim 12.