US3223731A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Recovery of diacid and diamine components of polyamide hydrolyzates
Assignee: Imperial Chemical Industries Ltd
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Filing: 1962-09-04
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Granted: 1965-12-14
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Expires: 1982-09-04
Abstract
No abstract record available.
Inventors
- 👤 Craig John Thorburn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 09:49
CPC Classifications
C; C07; C07C; C07C209/00; C07C209/82; C07C209/86; C07C27/00; C07C51/00; C07C51/06
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
173 words
A PROCESS FOR THE RECOVERY OF CONSTITUENT DIAMINE AND DIACID FROM A SYNTHETIC FIBRE-FORMING POLYAMIDE OBTAINED BY CONDENSING A DIAMINE SELECTED FROM THE GROUP CONSISTING OF ALIPHATIC AND AROMATIC DIAMINES WITH A DICARBOXYLIC ACID SELECTED FROM THE GROUP CONSISTING OF ALIPHATIC AND AROMATIC DICARBOXYLIC ACIDS, WHICH COMPRISES HYDROLIZING SAID POLYAMIDE UNDER PRESSURE IN AN INERT ATMOSPHERE AT A TEMPERATURE BETWEEN 160*C. AND THE TEMPERATURE OF DECOMPOSITION IN THE PRESENCE OF AN AQUEOUS SOLUTION CONTAINING AT LEST 20% EXCESS EQUIVALENTS OF AN ALKALI METAL HYDROXIDE, EXTRACTING THE DIAMINE FROM THE HYDROLYSIS PRODUCT WITH AN ORGANIC SOLVENT FOR SAID DIAMINE CAPABLE OF FORMING A TWO PHASE SYSTEM WHEN ADDED TO THE HYDROLYSIS PRODUCT AND HAVING A BOILING POINT SUFFICIENTLY REMOTE FROM THAT OF HE DIAMINE TO PERMIT SEPARATION OF SAID SOLVENT FROM SAID DIAMINE BY DISTILLATION, SAID SOLVENT BEING AN ALCOHOL FROM THE GROUP CONSISTING OF AN ALIPHATIC ALCOHOL COTAINING FROM 3 TO 8 CARBON ATOMS AND A CYCLOALIPHATIC ALCOHOL, AND SEPARATING THE SOLVENT SOLUTION OF DIAMINE FROM THE RESIDUAL AQUEOUS SOLUTION OF DIACID SALT.
Claim 2
Dependent Claim
173 words
A PROCESS FOR THE RECOVERY OF CONSTITUENT DIAMINE AND DIACID FROM A SYNTHETIC FIBRE-FORMING POLYAMIDE OBTAINED BY CONDENSING A DIAMINE SELECTED FROM THE GROUP CONSISTING OF ALIPHATIC AND AROMATIC DIAMINES WITH A DICARBOXYLIC ACID SELECTED FROM THE GROUP CONSISTING OF ALIPHATIC AND AROMATIC DICARBOXYLIC ACIDS, WHICH COMPRISES HYDROLIZING SAID POLYAMIDE UNDER PRESSURE IN AN INERT ATMOSPHERE AT A TEMPERATURE BETWEEN 160*C. AND THE TEMPERATURE OF DECOMPOSITION IN THE PRESENCE OF AN AQUEOUS SOLUTION CONTAINING AT LEST 20% EXCESS EQUIVALENTS OF AN ALKALI METAL HYDROXIDE, EXTRACTING THE DIAMINE FROM THE HYDROLYSIS PRODUCT WITH AN ORGANIC SOLVENT FOR SAID DIAMINE CAPABLE OF FORMING A TWO PHASE SYSTEM WHEN ADDED TO THE HYDROLYSIS PRODUCT AND HAVING A BOILING POINT SUFFICIENTLY REMOTE FROM THAT OF HE DIAMINE TO PERMIT SEPARATION OF SAID SOLVENT FROM SAID DIAMINE BY DISTILLATION, SAID SOLVENT BEING AN ALCOHOL FROM THE GROUP CONSISTING OF AN ALIPHATIC ALCOHOL COTAINING FROM 3 TO 8 CARBON ATOMS AND A CYCLOALIPHATIC ALCOHOL, AND SEPARATING THE SOLVENT SOLUTION OF DIAMINE FROM THE RESIDUAL AQUEOUS SOLUTION OF DIACID SALT.
References Cited (Backward Citations)
US2840606A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1968-12-13 | 1969-06-14 | 1969-12-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1972-12-13 | 1973-06-14 | 1973-12-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1976-12-13 | 1977-06-14 | 1977-12-14 | $7700.00 | Window Closed / Lapsed |