US4582642A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Recovery of caprolactam from process residues
Assignee: Honeywell International Inc
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Filing: 1984-06-27
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Granted: 1986-04-15
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Expires: 2004-06-27
Abstract
Abstract This invention is a method to recover caprolactam from a combined stream of mother liquor from a caprolactam crystallizer and other lactam containing aqueous streams, the improvement comprising steam distilling the combined stream at a temperature of from between about 180 DEG C. to 235 DEG C. in the absence of any depolymerization agent such as phosphoric acid; so that the residue from the steam distilling remains fluid; relatively low levels of caprolactam remain in the residue; less residue is generated; the recovered caprolactam has improved high quality; and losses of caprolactam due to side reactions are reduced.
Inventors
- 👤 Lamberto Crescentini
- 👤 William B. Fisher
- 👤 Richard E. Mayer
- 👤 Joseph D. DeCaprio
- 👤 Ronald K. Nilsen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 17:13
CPC Classifications
C; C07; C07D; C07D201/00; C07D201/16
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
97 words
In a method to recover caprolactam from a combined, concentrated stream of mother liquor from a caprolactam crystallizer and other concentrated lactam containing aqueous streams, the improvement comprising steam distilling said combined stream at a temperature of from between about 180° C. to 235° C. in the absence of any depolymerization agent such as phosphoric acid; so that the residue from said steam distilling remains fluid; relatively low levels of caprolactam remain in said residue; less said residue is generated; the recovered caprolactam has improved high quality; and losses of caprolactam due to side reactions are reduced.
Claim 2
Dependent Claim
97 words
In a method to recover caprolactam from a combined, concentrated stream of mother liquor from a caprolactam crystallizer and other concentrated lactam containing aqueous streams, the improvement comprising steam distilling said combined stream at a temperature of from between about 180° C. to 235° C. in the absence of any depolymerization agent such as phosphoric acid; so that the residue from said steam distilling remains fluid; relatively low levels of caprolactam remain in said residue; less said residue is generated; the recovered caprolactam has improved high quality; and losses of caprolactam due to side reactions are reduced.
Claim 3
Dependent Claim
89 words
In a method to recover caprolactam from a concentrated stream of mother liquor from a caprolactam crystallizer, the improvement comprising steam distilling said concentrated stream at a temperature of from between about 180° C. to 235° C. in the absence of any depolymerization agent such as phosphoric acid; so that the residue from said steam distilling remains fluid; relatively low levels of caprolactam remain in said residue; less said residue is generated; the recovered caprolactam has improved high quality; and losses of caprolactam due to side reactions are reduced.
Claim 4
Dependent Claim
89 words
In a method to recover caprolactam from a concentrated stream of mother liquor from a caprolactam crystallizer, the improvement comprising steam distilling said concentrated stream at a temperature of from between about 180° C. to 235° C. in the absence of any depolymerization agent such as phosphoric acid; so that the residue from said steam distilling remains fluid; relatively low levels of caprolactam remain in said residue; less said residue is generated; the recovered caprolactam has improved high quality; and losses of caprolactam due to side reactions are reduced.
References Cited (Backward Citations)
US4148793A
Cited
US4107160A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-04-14 | 1989-10-14 | 1990-04-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-04-14 | 1993-10-14 | 1994-04-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-04-14 | 1997-10-14 | 1998-04-15 | $7700.00 | Window Closed / Lapsed |