Patent US3725208A successfully refreshed from Google Patents.
US3725208A
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US
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Process for purification of acrylic acid from aldehydes by distillation with a reagent
Assignee: Nippon Kayaku Co Ltd
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Filing: 1971-08-20
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Granted: 1973-04-03
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Expires: 1991-08-20
Abstract
Abstract A PROCESS FOR THE REMOVAL OF SMALL AMOUNTS OF ALDEHYDE IMPURITIES FROM ACRYLIC ACID COMPRISES ADDING TO THE ACRYLIC ACID MINOR AMOUNTS OF A COMPOUND SELECTED FROM THE GROUP CONSISTING OF SULFURIC ACID, HYDRAZINE, PHENYLHYDRAZINE, ANALINE, MONOETHANOLAMINE, ETHYLENE DIAMINE AND GLYCINE, AND SUBJECTING THE ACRYLIC ACID MIXTURE TO DISTILLATION.
Inventors
- 👤 S Maezawa
- 👤 H Yoshikawa
- 👤 M Hashimoto
- 👤 K Sakamoto
- 👤 J Fujii
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 19:56
CPC Classifications
C; C07; C07C; C07C51/00; C07C51/42; C07C51/487; C07C51/43; C07C51/44; C07C51/50; Y; Y10; Y10S; Y10S203/00; Y10S203/22
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-04-02 | 1976-10-02 | 1977-04-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-02 | 1980-10-02 | 1981-04-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-02 | 1984-10-02 | 1985-04-03 | $7700.00 | Window Closed / Lapsed |