US2802777A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process of purifying crude 2-pyrrolidone
Assignee: GAF Chemicals Corp
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Filing: 1956-05-10
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Granted: 1957-08-13
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Expires: 1976-05-10
Abstract
No abstract record available.
Inventors
- 👤 Lester J Lohr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 17:40
CPC Classifications
C; C07; C07D; C07D207/00; C07D207/02; C07D207/18; C07D207/22; C07D207/24; C07D207/26; C07D207/263; C07D207/267; C07D201/00; C07D201/16
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
84 words
THE PROCESS FOR PURIFYING 2-PYRROLIDONE COMPRISING THE STEPS OF FORMING A PYRROLIDONE HYDRATE WITH WATER, COOLING THE HYDRATE AND IMPURITIES TO APPROXIMATELY 0* C. TO CRYSTALLIZE THE PYRROLIDONE HYDRATE, SEPARATING THE CRYSTALLINE PYRROLIDONE HYDRATE FROM RESIDUAL IMPURITIES, DISTILLING THE PURE HYDRATE WITH A SUBSTANCE WHICH FORMS AN AZEOTROPIC MIXTURE WITH WATER, WHICH HAS A BOILING POINT REASONABLY NEAR THAT OF WATER, IS NON-REACTIVE WITH THE PYRROLIDONE AND HAS NO NON-VOLATILE IMPURITIES TO REMOVE THE HYDRATE WATER AND FLASH DISTILLING THE PURIFIED PYRROLIDONE UNDER VACUUM.
Claim 2
Dependent Claim
84 words
THE PROCESS FOR PURIFYING 2-PYRROLIDONE COMPRISING THE STEPS OF FORMING A PYRROLIDONE HYDRATE WITH WATER, COOLING THE HYDRATE AND IMPURITIES TO APPROXIMATELY 0* C. TO CRYSTALLIZE THE PYRROLIDONE HYDRATE, SEPARATING THE CRYSTALLINE PYRROLIDONE HYDRATE FROM RESIDUAL IMPURITIES, DISTILLING THE PURE HYDRATE WITH A SUBSTANCE WHICH FORMS AN AZEOTROPIC MIXTURE WITH WATER, WHICH HAS A BOILING POINT REASONABLY NEAR THAT OF WATER, IS NON-REACTIVE WITH THE PYRROLIDONE AND HAS NO NON-VOLATILE IMPURITIES TO REMOVE THE HYDRATE WATER AND FLASH DISTILLING THE PURIFIED PYRROLIDONE UNDER VACUUM.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1960-08-12 | 1961-02-11 | 1961-08-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1964-08-12 | 1965-02-11 | 1965-08-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1968-08-12 | 1969-02-11 | 1969-08-13 | $7700.00 | Window Closed / Lapsed |