Patent US3290329A successfully refreshed from Google Patents.
US3290329A
Expired / Lapsed
US
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Purification of pyrrolidone
Assignee: BASF SE
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Filing: 1964-11-25
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Granted: 1966-12-06
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Expires: 1984-11-25
Abstract
No abstract record available.
Inventors
- 👤 Doerfel Helmut
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 16:28
CPC Classifications
C; C08; C08G; C08G69/00; C08G69/02; C08G69/08; C08G69/14; C08G69/24; C07; C07D; C07D201/00; C07D201/16
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
48 words
A PROCESS FOR PURIFYING TECHNICAL GRADE PYRROLIDONE INTENDED FOR POLYMERIZATION WHICH COMPRISES RECRYSTALLIZING THE PYRROLIDONE AT FROM -70* TO +20*C. FROM A MEMBER SELECTED FROM THE GROUP CONSISTING OF AN ALKANOL HAVING ONE TO SIX CARBON ATOMS, AN ALKANONE HAVING THREE TO SEVEN CARBON ATOMS AND MIXTURES THEREOF.
Claim 2
Dependent Claim
48 words
A PROCESS FOR PURIFYING TECHNICAL GRADE PYRROLIDONE INTENDED FOR POLYMERIZATION WHICH COMPRISES RECRYSTALLIZING THE PYRROLIDONE AT FROM -70* TO +20*C. FROM A MEMBER SELECTED FROM THE GROUP CONSISTING OF AN ALKANOL HAVING ONE TO SIX CARBON ATOMS, AN ALKANONE HAVING THREE TO SEVEN CARBON ATOMS AND MIXTURES THEREOF.
References Cited (Backward Citations)
US2802777A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1969-12-05 | 1970-06-06 | 1970-12-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1973-12-05 | 1974-06-06 | 1974-12-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1977-12-05 | 1978-06-06 | 1978-12-06 | $7700.00 | Window Closed / Lapsed |