Patent US2840553A successfully refreshed from Google Patents.
US2840553A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of preparing caprolactam
Assignee: —
•
Filing: —
•
Granted: 1958-06-24
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Expires: 1975-06-24
Abstract
No abstract record available.
Inventors
No inventors recorded.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:10
CPC Classifications
C; C07; C07D; C07D201/00; C07D201/02; C07D201/08
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
42 words
THE METHOD OF PREPARING E-CAPROLACTAM COMPRISING REACTING A MATERIAL OF THE GROUP CONSISTING OF E-HYDROXYCAPROIC ACID AMIDE, AMMONIUM SALT OF E-HYDROXYCAPROIC ACID, AND MIXTURES THEREOF, IN AQUEOUS AMMONIA SOLUTION UNDER CONDITIONS OF SUPERATMOSPHERIC PRESSURE AND TEMPERATURE FROM ABOUT 250*C. TO ABOUT 300*C.
Claim 2
Independent Claim
42 words
THE METHOD OF PREPARING E-CAPROLACTAM COMPRISING REACTING A MATERIAL OF THE GROUP CONSISTING OF E-HYDROXYCAPROIC ACID AMIDE, AMMONIUM SALT OF E-HYDROXYCAPROIC ACID, AND MIXTURES THEREOF, IN AQUEOUS AMMONIA SOLUTION UNDER CONDITIONS OF SUPERATMOSPHERIC PRESSURE AND TEMPERATURE FROM ABOUT 250*C. TO ABOUT 300*C.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1961-06-23 | 1961-12-23 | 1962-06-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1965-06-23 | 1965-12-23 | 1966-06-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1969-06-23 | 1969-12-23 | 1970-06-24 | $7700.00 | Window Closed / Lapsed |