Patent US3855080A successfully refreshed from Google Patents.
US3855080A
Expired / Lapsed
US
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Recovery of caprolactam from oligomers by heating and film distillation
Assignee: BASF SE
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Filing: 1972-07-06
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Granted: 1974-12-17
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Expires: 1992-07-06
Abstract
Abstract Caprolactam is recovered from a mixture which contains caprolactam and oligomers of the same by distillation at temperatures above the melting point of the oligomers or mixture thereof contained in the residue at atmospheric or slightly increased pressure. The process is of importance for removing residues of caprolactam oligomer residues and thus for effluent pollution control.
Inventors
- 👤 L Becker
- 👤 K Kahr
- 👤 G Rapp
- 👤 O Waschka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 07:03
CPC Classifications
C; C07; C07D; C07D201/00; C07D201/16
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
80 words
A CONTINUOUS PROCESS FOR SEPARATING CAPROLACTAM FROM A MIXTURE CONTAINING FROM ABOUT 70 85 PERCENT OF CAPROLACTAN AND FROM 15 TO 30 PERCENT OF OLIGOMERS OF CAPROLACTAM WHICH COMPRISES HEATING SAID MIXTURE OF CAPROLACTAM AND OLIGOMERS TO A TEMPERATURE OF FROM 250* TO 350*C TO OBTAIN A MELT, FEEDING SAID MELT TO A FALLING FILM EVAPORATOR HELD AT ATMOSPHERIC PRESSURE OR SLIGHTLY ABOVE ATMOSPHERIC PRESSURE, WHEREBY CAPROLACTAM IS DISTILLED OFF, AND CONTAINUOUSLY REMOVING SAID OLIGOMERS FROM SAID EVAPORATOR AS BOTTOMS.
Claim 2
Dependent Claim
80 words
A CONTINUOUS PROCESS FOR SEPARATING CAPROLACTAM FROM A MIXTURE CONTAINING FROM ABOUT 70 85 PERCENT OF CAPROLACTAN AND FROM 15 TO 30 PERCENT OF OLIGOMERS OF CAPROLACTAM WHICH COMPRISES HEATING SAID MIXTURE OF CAPROLACTAM AND OLIGOMERS TO A TEMPERATURE OF FROM 250* TO 350*C TO OBTAIN A MELT, FEEDING SAID MELT TO A FALLING FILM EVAPORATOR HELD AT ATMOSPHERIC PRESSURE OR SLIGHTLY ABOVE ATMOSPHERIC PRESSURE, WHEREBY CAPROLACTAM IS DISTILLED OFF, AND CONTAINUOUSLY REMOVING SAID OLIGOMERS FROM SAID EVAPORATOR AS BOTTOMS.
Claim 3
Dependent Claim
22 words
A process as claimed in claim 1, wherein the mixture of caprolactam and oligomers has been obtained from extraction liquids of polycaprolactam.
References Cited (Backward Citations)
US2952675A
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US3252502A
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US3449220A
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US3497500A
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US3600381A
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US3686077A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-12-16 | 1978-06-17 | 1978-12-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-16 | 1982-06-17 | 1982-12-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-16 | 1986-06-17 | 1986-12-17 | $7700.00 | Window Closed / Lapsed |