Patent US3062879A successfully refreshed from Google Patents.
US3062879A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparing perfluoroalkanedioic acids
Assignee: EIDP Inc
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Filing: 1961-05-15
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Granted: 1962-11-06
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Expires: 1981-05-15
Abstract
No abstract record available.
Inventors
- 👤 John J Drysdale
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 13:11
CPC Classifications
C; C07; C07C; C07C51/00; C07C51/16; C07C51/305
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
79 words
THE PROCESS FOR PREPARING A PERFLUOROALKANEDIOIC ACID WHICH COMPRISES HEATING A BIS(ALKYLTHIO)PERFLUOROALKANE OF THE FORMULA RS(CF2CF2)NSR WHEREIN R IS AN ALKYL RADICAL OF 1 TO 6 CARBON ATOMS AND N IS AN INTEGER OF FROM 2 TO 20 WITH FROM ABOUT 1 TO ABOUT 4 PARTS BY WEIGHT OF CONCENTRATED SULFURIC ACID OF FROM ABOUT 80% TO 100% STRENGTH AT A TEMPERATURE OF FROM ABOUT 100* C. TO ABOUT 350*C., AND RECOVERING THE PERFLUOROALKANEDIOIC ACID FROM THE REACTION MIXTURE.
Claim 2
Dependent Claim
79 words
THE PROCESS FOR PREPARING A PERFLUOROALKANEDIOIC ACID WHICH COMPRISES HEATING A BIS(ALKYLTHIO)PERFLUOROALKANE OF THE FORMULA RS(CF2CF2)NSR WHEREIN R IS AN ALKYL RADICAL OF 1 TO 6 CARBON ATOMS AND N IS AN INTEGER OF FROM 2 TO 20 WITH FROM ABOUT 1 TO ABOUT 4 PARTS BY WEIGHT OF CONCENTRATED SULFURIC ACID OF FROM ABOUT 80% TO 100% STRENGTH AT A TEMPERATURE OF FROM ABOUT 100* C. TO ABOUT 350*C., AND RECOVERING THE PERFLUOROALKANEDIOIC ACID FROM THE REACTION MIXTURE.
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) | 1965-11-05 | 1966-05-07 | 1966-11-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1969-11-05 | 1970-05-07 | 1970-11-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1973-11-05 | 1974-05-07 | 1974-11-06 | $7700.00 | Window Closed / Lapsed |