Patent US3156683A successfully refreshed from Google Patents.
US3156683A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Purification of caprolactam
Assignee: —
•
Filing: —
•
Granted: 1964-11-10
•
Expires: 1981-11-10
Abstract
No abstract record available.
Inventors
No inventors recorded.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 12:18
CPC Classifications
C; C07; C07D; C07D201/00; C07D201/02; C07D201/04; C07D201/16; C07D201/08; C07D223/00; C07D223/02; C07D223/06; C07D223/08; C07D223/10
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
128 words
IN A PROCESS FOR THE PURIFICATION OF CAPROLACTAM PRODUCED BY THE BECKMANN REARRANGEMENT OF CYCLOHEXANONE OXIME, THE STEPS WHICH COMPRISE REFLUXING SUBSTANTIALLY ANHYDROUS CAPROLACTAM AT PRESSURES RANGING FROM ABOUT 5 TO ABOUT 50 MM. AND AT LIQUID TEMPERATURES RANGING FROM ABOUT 115 TO ABOUT 175*C., WHILE CONTINUALLY BUBBLING THROUGH THE LIQUID CAPROLACTAM A GAS INERT TO CAPROLACTAM SELECTED FROM THE GROUP CONSISTING OF NITROGEN, NEON, ARGON, XENON, CARBON DIOXIDE, METHANE, AND HYDROGEN, CONDENSING THE REFLUXING CAPROLACTAM AT TEMPERATURES RANGING FROM ABOUT 20*C. TO ABOUT 100*C., SAID REFLUX BEING CONTINUED UNTIL THE CAPROLACTAM CONTAINS LESS THAN 25 P.P.M. OF VOLATILE BASE CALCULATED QUANTITATIVELY AS AMMONIA AND THEN DISTILLING THE CAPROLACTAM AT TEMPERATURES RANGING FROM 115 TO ABOUT 175*C. AND AT PRESSURES RANGING FROM ABOUT 5 TO ABOUT 50 MM.
Claim 2
Dependent Claim
128 words
IN A PROCESS FOR THE PURIFICATION OF CAPROLACTAM PRODUCED BY THE BECKMANN REARRANGEMENT OF CYCLOHEXANONE OXIME, THE STEPS WHICH COMPRISE REFLUXING SUBSTANTIALLY ANHYDROUS CAPROLACTAM AT PRESSURES RANGING FROM ABOUT 5 TO ABOUT 50 MM. AND AT LIQUID TEMPERATURES RANGING FROM ABOUT 115 TO ABOUT 175*C., WHILE CONTINUALLY BUBBLING THROUGH THE LIQUID CAPROLACTAM A GAS INERT TO CAPROLACTAM SELECTED FROM THE GROUP CONSISTING OF NITROGEN, NEON, ARGON, XENON, CARBON DIOXIDE, METHANE, AND HYDROGEN, CONDENSING THE REFLUXING CAPROLACTAM AT TEMPERATURES RANGING FROM ABOUT 20*C. TO ABOUT 100*C., SAID REFLUX BEING CONTINUED UNTIL THE CAPROLACTAM CONTAINS LESS THAN 25 P.P.M. OF VOLATILE BASE CALCULATED QUANTITATIVELY AS AMMONIA AND THEN DISTILLING THE CAPROLACTAM AT TEMPERATURES RANGING FROM 115 TO ABOUT 175*C. AND AT PRESSURES RANGING FROM ABOUT 5 TO ABOUT 50 MM.
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) | 1967-11-10 | 1968-05-11 | 1968-11-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1971-11-10 | 1972-05-11 | 1972-11-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1975-11-10 | 1976-05-11 | 1976-11-10 | $7700.00 | Window Closed / Lapsed |