US2806861A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Purification of maleic anhydride
Assignee: Monsanto Chemicals Ltd
•
Filing: 1955-07-28
•
Granted: 1957-09-17
•
Expires: 1975-07-28
Abstract
No abstract record available.
Inventors
- 👤 Cummings Howard David
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 21:33
CPC Classifications
C; C07; C07C; C07C51/00; C07C51/54; C07C51/573
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
31 words
IN A PROCESS FOR PURIFYING MALEIC ANHYDRIDE, THE STEP COMPRISING HEATING MALEIC ANHYDRIDE IN THE PRESENCE OF AT LEAST 0.1% BY WEIGHT OF MANGANESE DIOXIDE AND RECOVERING THE PURIFIED MALEIC ANHYDRIDE.
Claim 2
Dependent Claim
31 words
IN A PROCESS FOR PURIFYING MALEIC ANHYDRIDE, THE STEP COMPRISING HEATING MALEIC ANHYDRIDE IN THE PRESENCE OF AT LEAST 0.1% BY WEIGHT OF MANGANESE DIOXIDE AND RECOVERING THE PURIFIED MALEIC ANHYDRIDE.
References Cited (Backward Citations)
US2734854A
Cited
US2134531A
Cited
US2296218A
Cited
US2309167A
Cited
US2308588A
Cited
US2343536A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1960-09-16 | 1961-03-18 | 1961-09-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1964-09-16 | 1965-03-18 | 1965-09-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1968-09-16 | 1969-03-18 | 1969-09-17 | $7700.00 | Window Closed / Lapsed |