Claims
- 1. A method of refining solid reaction grade 2-acrylamido-2-methylpropane sulfonic acid which has not previously undergone the dissolution and recrystallization steps used in the Lubrizol refining procedure, consisting of the steps:
- mixing a quantity of the solid acid with a quantity of a liquid monohydric alcohol without significant dissolution of the acid;
- agitating the mixture;
- separating the solid acid from the alcohol; and
- drying the acid to substantially remove any remaining alcohol.
- 2. The method of claim 1 wherein the mixture contains about 25-35% by weight of the acid.
- 3. The method of either of the foregoing claims 1 or 2 wherein the mixture is heated for a time, the heating temperature being below that which would cause any significant dissolution of the acid in the alcohol.
- 4. The method of either of the foregoing claims 1 or 2 wherein the mixture is heated to a temperature below the boiling point of the alcohol.
- 5. The method of either of the foregoing claims 1 or 2 wherein the mixture is heated to a temperature between about 25.degree. C. to about 60.degree. C.
- 6. The method of claim 5 wherein the heating period is between about 1/2 hour and about 24 hours.
- 7. The method of claim 1 wherein separation of the acid from the alcohol is effected by filtration.
- 8. The method of claim 1 wherein separation of the acid from the alcohol is effected by centrifugation.
- 9. The method of claim 1 wherein drying of the refined acid is effected by vacuum drying.
- 10. The method of claim 1 wherein drying of the refined acid is effected by heating under a vacuum or at ambient pressure.
- 11. The method of claim 10 wherein the heating temperature is between about 25.degree. C. and 70.degree. C.
- 12. The method of claim 1 wherein the alcohol is selected from the group consisting of methyl alcohol, ethyl alcohol, isopropyl alcohol and mixtures thereof.
- 13. The method of claim 12 wherein the alcohol is anhydrous methyl alcohol.
- 14. The method of claim 12 wherein the alcohol is anhydrous isopropyl alcohol.
- 15. The method of claim 12 wherein the alcohol is absolute ethyl alcohol.
- 16. The method of claim 3 wherein the mixture is cooled before separation of the acid from the alcohol is effected.
- 17. The method of claim 11 wherein the drying is effected for a period of between about 2-3 hours.
- 18. The method of claim 9 wherein drying is effected in a rotary vacuum dryer.
- 19. A method of refining solid reaction grade 2-acrylamido-2-methylpropane sulfonic acid which has not previously undergone the dissolution and recrystallization steps used in the Lubrizol refining procedure, consisting of the steps:
- mixing the solid acid in an alcohol selected from the group consisting of methyl alcohol, ethyl alcohol, isopropyl alcohol, and mixtures thereof without substantial dissolution of the acid;
- agitating the mixture for between about 1/2 to 2 hours at a temperature of between about 25.degree.-60.degree. C.;
- separating the solid acid from the alcohol; and
- drying the acid.
- 20. The method of claim 19 wherein the mixture contains about 25-35% by weight acid.
- 21. The method of claim 19 wherein separation is by filtering or centrifugation.
- 22. The method of claim 19 wherein drying is effected under vacuum at 50.degree. C. for between about 2-3 hours.
- 23. The method of claim 22 wherein the vacuum level is about 1 mm Hg pressure.
- 24. The method of claim 19 wherein the methyl alcohol is anhydrous.
- 25. The method of claim 19 wherein the mixture is cooled to about 20.degree. C. or less before separation is effected.
- 26. The method of claim 25 wherein the mixture is held at the cooling temperature for about 11/2 hours prior to separation of the acid from the alcohol.
- 27. The method of claim 19 wherein the percent by weight of the acid is 30%.
- 28. The method of claim 19 wherein the mixing time is about 2 hours.
- 29. The method of claim 19 wherein the mixing temperature is about 40.degree. C.
- 30. The method of claim 19 wherein the isopropyl alcohol is anhydrous.
- 31. The method of claim 19 wherein the ethyl alcohol is absolute.
Parent Case Info
This is a continuation-in-part application of copending patent application Ser. No. 123,356, filed Feb. 21, 1980, entitled "REFINING OF 2-ACRYLAMIDO-2-METHYLPROPANE SULFONIC ACID", now abandoned. This continuation-in-part application is assigned to the same assignee as is the parent application i.e., Medtronic, Inc.
Non-Patent Literature Citations (3)
Entry |
"Process for the Production of Refined AMPS", 12/76. |
Weissberger, "Separation & Purification", Part I, 2nd ed. (1956), pp. 548-549, 742-744. |
Lubrizol Corp. Brochure. |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
123356 |
Feb 1980 |
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