Patent US4794263A successfully refreshed from Google Patents.
Patent US2935183A successfully refreshed from Google Patents.
Patent US2933672A successfully refreshed from Google Patents.
US4154729A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Continuous extraction of caprolactam from crude lactam
Assignee: BASF SE
•
Filing: 1977-11-03
•
Granted: 1979-05-15
•
Expires: 1997-11-03
Abstract
Abstract In a process for the continuous extraction of caprolactam from crude lactam by means of benzene in counter-current, in which crude lactam is fed into the upper part of an extraction zone and benzene into the lower part, a solution of caprolactam in benzene is taken off at the top and an aqueous solution containing impurities is taken off at the bottom, the improvement that water is additionally fed into the upper part of the extraction zone and a part of the aqueous solution, containing impurities, obtained at the bottom of the extraction zone is recycled into the extraction zone. Caprolactam is used for the manufacture of nylon.
Inventors
- 👤 Hugo Fuchs
- 👤 Uwe Brand
- 👤 Klaus Kartte
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 02:16
CPC Classifications
C; C07; C07D; C07D201/00; C07D201/16
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
99 words
In a process for the continuous extraction of caprolactam from crude lactam by means of benzene in counter-current, in which crude lactam is fed into the upper part of an extraction zone and benzene into the lower part, a solution of caprolactam in benzene is taken off at the top and an aqueous solution containing impurities is taken off at the bottom, wherein the improvement comprises: additionally feeding water into the upper part of the extraction zone and recycling a part of the aqueous solution, conntaining impurities, obtained at the bottom of the extraction zone into the extraction zone.
Claim 2
Dependent Claim
99 words
In a process for the continuous extraction of caprolactam from crude lactam by means of benzene in counter-current, in which crude lactam is fed into the upper part of an extraction zone and benzene into the lower part, a solution of caprolactam in benzene is taken off at the top and an aqueous solution containing impurities is taken off at the bottom, wherein the improvement comprises: additionally feeding water into the upper part of the extraction zone and recycling a part of the aqueous solution, conntaining impurities, obtained at the bottom of the extraction zone into the extraction zone.
Claim 3
Dependent Claim
34 words
A process as set forth in claim 1, in which a total of from 17 to 25 parts by weight of water are additionally fed in per 100 parts by weight of crude lactam.
Claim 4
Dependent Claim
32 words
A process as set forth in claim 1, in which from 0.09 to 0.36 times the amount of aqueous solution, containing impurities, obtained at the bottom of the extraction zone is recycled.
Claim 5
Dependent Claim
39 words
A process as set forth in claim 1, in which the additional water fed in, and the recycled part of the aqueous solution containing impurities, are fed into the extraction zone above the feed point of the crude lactam.
Claim 6
Dependent Claim
29 words
A process as set forth in claim 1, in which the recycled amount of aqueous solution containing impurities is fed into the extraction zone together with the crude lactam.
Claim 7
Dependent Claim
21 words
A process as set forth in claim 1, in which the extraction is carried out at from 40° to 60° C.
Claim 8
Dependent Claim
30 words
A process as set forth in claim 1, in which the amount by weight of benzene used is from 2 to 12 times the amount by weight of crude lactam.
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) | 1982-05-14 | 1982-11-13 | 1983-05-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-05-14 | 1986-11-13 | 1987-05-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-05-14 | 1990-11-13 | 1991-05-15 | $7700.00 | Window Closed / Lapsed |