US5360905A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Recovery of caprolactam from oligomers and/or polymers of caprolactam
Assignee: BASF SE
•
Filing: 1993-05-14
•
Granted: 1994-11-01
•
Expires: 2013-05-14
Abstract
Abstract A process for recovering caprolactam from oligomers and/or polymers of caprolactam comprises the following steps: a) treating oligomers and/or polymers of caprolactam with from 1 to 20 parts by weight of water per part by weight of oligomer or polymer at from 200° to 350° C. under superatmospheric pressure with a residence time of from 0.5 to 10 hours to form an aqueous reaction mixture comprising polycaprolactam, monomeric caprolactam and oligomers thereof, and b) passing the aqueous reaction mixture obtained in a) into a fluidized bed of alumina at from 250° to 400° C. to obtain a mixture of steam and caprolactam.
Inventors
- 👤 Hugo Fuchs
- 👤 Claus-Ulrich Priester
- 👤 Gerald Neubauer
- 👤 Erwin Brunner
- 👤 Josef Ritz
- 👤 Michael Kopietz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 18:46
CPC Classifications
C; C07; C07D; C07D201/00; C07D201/02; C07D201/12
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
107 words
A process for recovering caprolactam from oligomers and/or polymers of caprolactam, comprising the following steps: a) treating oligomers and/or polymers of caprolactam with from 1 to 20 parts by weight of water per part by weight of oligomer or polymer at from 200° to 350° C. under superatmospheric pressure with a residence time of from 0.5 to 10 hours in a liquid aqueous phase to form an aqueous reaction mixture comprising polycaprolactam, monomeric caprolactam and oligomers thereof, and b) passing the aqueous reaction mixture obtained in a) into a fluidized bed of alumina at from 250° to 400° C. to obtain a mixture of steam and caprolactam.
Claim 2
Dependent Claim
107 words
A process for recovering caprolactam from oligomers and/or polymers of caprolactam, comprising the following steps: a) treating oligomers and/or polymers of caprolactam with from 1 to 20 parts by weight of water per part by weight of oligomer or polymer at from 200° to 350° C. under superatmospheric pressure with a residence time of from 0.5 to 10 hours in a liquid aqueous phase to form an aqueous reaction mixture comprising polycaprolactam, monomeric caprolactam and oligomers thereof, and b) passing the aqueous reaction mixture obtained in a) into a fluidized bed of alumina at from 250° to 400° C. to obtain a mixture of steam and caprolactam.
Claim 3
Dependent Claim
29 words
The process of claim 1, wherein the water is employed in an amount of from 2 to 10 parts by weight of water per part by weight of oligomer/polymer.
Claim 4
Dependent Claim
17 words
The process of claim 1, wherein stage a) is carried out at from 250° to 300° C.
Claim 5
Dependent Claim
20 words
The process of claim 1, wherein stage a) is carried out at a pressure of from 15 to 200 bar.
Claim 6
Dependent Claim
21 words
The process of claim 1, wherein stage a) is carried out with the additional presence of phosphoric acid or sodium hydroxide.
Claim 7
Dependent Claim
17 words
The process of claim 1, wherein stage b) is carried out at from 290° to 360° C.
Claim 8
Dependent Claim
11 words
The process of claim 1, wherein the alumina used is γ-alumina.
Claim 9
Dependent Claim
19 words
The process of claim 1, wherein the residence time in the fluidized bed is from 0.1 to 30 seconds.
Claim 10
Dependent Claim
30 words
The process of claim 1, wherein the aqueous reaction mixture of stage a) is passed into the fluidized bed of stage b) directly via a nozzle opening without prior depressurization.
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) | 1997-10-31 | 1998-05-02 | 1998-11-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-10-31 | 2002-05-02 | 2002-11-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-10-31 | 2006-05-02 | 2006-11-01 | $7700.00 | Window Closed / Lapsed |