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US4337215A
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Process for purifying 2-acrylamido-2-methylpropanesulfonic acid
Assignee: Mitsubishi Chemical Corp
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Filing: 1979-01-31
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Granted: 1982-06-29
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Expires: 1999-01-31
Abstract
Abstract This disclosure relates to a process for the purification of 2-acrylamido-2-methylpropanesulfonic acid, which comprises dissolving said sulfonic acid in hydrous acetic acid of a water content of 3 to 80% by weight at 60 DEG to 110 DEG C. and subjecting the resulting solution to recrystallization. The purified product thus obtained is useful particularly as a starting material in preparing a high-molecular-weight polymer or copolymer.
Inventors
- 👤 Shunichi Doi
- 👤 Masatake Kamogawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 08:02
CPC Classifications
C; C07; C07C; C07C303/00; C07C303/42; C07C309/00; C07C309/01; C07C309/02; C07C309/03; C07C309/13; C07C309/14; C07C309/15
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
39 words
A process for purifying 2-acrylamido-2-methylpropanesulfonic acid, which comprises dissolving crystals of 2-acrylamido-2-methylpropanesulfonic acid in hydrous acetic acid having a water content of 3 to 80% by weight at 60° to 110° C. and subjecting the resulting solution to recrystallization.
Claim 2
Dependent Claim
39 words
A process for purifying 2-acrylamido-2-methylpropanesulfonic acid, which comprises dissolving crystals of 2-acrylamido-2-methylpropanesulfonic acid in hydrous acetic acid having a water content of 3 to 80% by weight at 60° to 110° C. and subjecting the resulting solution to recrystallization.
Claim 3
Dependent Claim
26 words
A process according to claim 1, wherein the weight ratio of the hydrous acetic acid to the crystals of 2-acrylamido-2-methylpropanesulfonic acid is from 2/1 to 7/1.
Claim 4
Dependent Claim
23 words
A process according to claim 1 or 2, wherein the water content of the hydrous acetic acid is 5 to 40% by weight.
Claim 5
Dependent Claim
21 words
A process according to claim 1 or 2, wherein the temperature for the dissolution of crystals is 80° to 100° C.
Claim 6
Dependent Claim
41 words
A process according to claim 1, wherein after dissolving the crystals of 2-acrylamido-2-methylpropanesulfonic acid in the hydrous acetic acid, the water content of the hydrous acetic acid is reduced by adding acetic anhydride or glacial acetic acid, thereby recrystallizing 2-acrylamido-2-methylpropanesulfonic acid.
Claim 7
Dependent Claim
35 words
A process according to claim 1, wherein after dissolving the crystals of 2-acrylamido-2-methylpropanesulfonic acid in the hydrous acetic acid, the water content of the hydrous acetic acid is reduced by distillation, thereby recrystallizing 2-acrylamido-2-methylpropanesulfonic acid.
Claim 8
Dependent Claim
22 words
A process according to claim 1, wherein the mother liquor from which the crystals have been separated is re-used as the solvent.
Claim 9
Dependent Claim
17 words
A process according to claim 1 wherein the solution is subjected to recrystallization by cooling the solution.
References Cited (Backward Citations)
GB1090779A
Cited
DE2523616A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-06-28 | 1985-12-28 | 1986-06-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-06-28 | 1989-12-28 | 1990-06-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-06-28 | 1993-12-28 | 1994-06-29 | $7700.00 | Window Closed / Lapsed |