US2863922A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Preparation of ketene
Assignee: F Hoffmann La Roche AG
•
Filing: 1956-10-02
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Granted: 1958-12-09
•
Expires: 1976-10-02
Abstract
No abstract record available.
Inventors
- 👤 Sturzenegger August
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 13:24
CPC Classifications
C; C07; C07C; C07C45/00; C07C45/87; C07C45/88
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
51 words
IN A PROCESS FOR MAKING KETENE BY THERMAL DECOMPOSITION OF ACETONE, THE IMPROVEMENT WHICH COMPRISES DECOMPOSING THE ACETONE IN A REACTION VESSEL THE INNER SURFACE OF WHICH IS CONSTRUCTED OF A STEEL HAVING ESSENTIALLY THE COMPOSITION: FROM ABOUT 14% TO ABOUT 18% CHROMIUM, A MAXIMUM OF ABOUT 0.12% CARBON, BALANCE IRON.
Claim 2
Dependent Claim
51 words
IN A PROCESS FOR MAKING KETENE BY THERMAL DECOMPOSITION OF ACETONE, THE IMPROVEMENT WHICH COMPRISES DECOMPOSING THE ACETONE IN A REACTION VESSEL THE INNER SURFACE OF WHICH IS CONSTRUCTED OF A STEEL HAVING ESSENTIALLY THE COMPOSITION: FROM ABOUT 14% TO ABOUT 18% CHROMIUM, A MAXIMUM OF ABOUT 0.12% CARBON, BALANCE IRON.
References Cited (Backward Citations)
US2069243A
Cited
US2393778A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1961-12-08 | 1962-06-09 | 1962-12-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1965-12-08 | 1966-06-09 | 1966-12-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1969-12-08 | 1970-06-09 | 1970-12-09 | $7700.00 | Window Closed / Lapsed |