Patent US3764543A successfully refreshed from Google Patents.
US2580221A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Catalytic dehydrogenation of piperazine to pyrazine
Assignee: Wyeth Holdings LLC
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Filing: 1946-04-12
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Granted: 1951-12-25
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Expires: 1966-04-12
Abstract
No abstract record available.
Inventors
- 👤 Dixon James Kenneth
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 14:43
CPC Classifications
C; C07; C07D; C07D241/00; C07D241/02; C07D241/10; C07D241/12
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
59 words
THE METHOD OF PRODUCING PYRAZINE WHICH COMPRISES COMPLETELY VAPORIZING PIPERAZINE; PASSING THE VAPORIZED MATERIAL OVER A CATALYST,SELECTED FROM THE GROUP CONSISTING OF MATERIALS OF THE FORMULAE M AND MO, WHERE M REPRESENTS COBALT, NICKEL AND COPPER, AND FE2O3, TEMPERATURES OF FROM 350*-450* C.; CONDESING THE CONDENSABLE PORTION OF THE REACTED VAPORS AND ISOLATING THE PYRAZINE CONTENT OF THE CONDENSATE.
Claim 2
Independent Claim
59 words
THE METHOD OF PRODUCING PYRAZINE WHICH COMPRISES COMPLETELY VAPORIZING PIPERAZINE; PASSING THE VAPORIZED MATERIAL OVER A CATALYST,SELECTED FROM THE GROUP CONSISTING OF MATERIALS OF THE FORMULAE M AND MO, WHERE M REPRESENTS COBALT, NICKEL AND COPPER, AND FE2O3, TEMPERATURES OF FROM 350*-450* C.; CONDESING THE CONDENSABLE PORTION OF THE REACTED VAPORS AND ISOLATING THE PYRAZINE CONTENT OF THE CONDENSATE.
References Cited (Backward Citations)
US2184235A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1954-12-24 | 1955-06-25 | 1955-12-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1958-12-24 | 1959-06-25 | 1959-12-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1962-12-24 | 1963-06-25 | 1963-12-25 | $7700.00 | Window Closed / Lapsed |