US3904609A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for the preparation of pure lactam from its primary solutions in an organic solvent
Assignee: SNIA Viscosa SpA
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Filing: 1973-07-18
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Granted: 1975-09-09
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Expires: 1993-07-18
Abstract
Abstract A method for the preparation of pure lactam is disclosed wherein a primary solution of the lactam in an organic phenolic solvent is supplemented by a compound miscible with the solution which is compatible with the primary solvent and is a solvent for the primary solvent but not for the lactam and susceptible of giving rise to precipitation of the lactam, the lactam being then separated from the mixture of the primary solvent and the compound which is a solvent for said primary solvent.
Inventors
- 👤 Roberto Mattone
- 👤 Giancarlo Sioli
- 👤 Luigi Giuffre
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 06:41
CPC Classifications
C; C07; C07D; C07D201/00; C07D201/16
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
116 words
A METHOD FOR THE PREPARATION OF A PURE CAPROLACTAM FROM A DILUTED ACIDIC SOLUTION THEREOF, COMPRISING FIRST EXTRACTING THE CAPROLACTAM FROM THE SAID DILUTED ACIDIC SOLUTION THEREOF WITH A PRIMARY SUBSTITUTED PHENOL SOLVENT TO FORM A CAPROLACTAM-CONTAINING PRIMARY SOLUTION, SUPPLEMENTING SAID PRIMARY SOLUTION WITH A COMPOUND COMPATIBLE WITH SAID PRIMARY SOLVENT, AND SELECTED FROM THE GROUP CONSISTING OF CYCLOHEXANE, TOLUENE, BENZENE, AND ALIPHATIC, AROMATIC AND CHLORINATED HYDROCARBONS, AND WITH A SECONDARY SOLVENT FOR THE CAPROLACTAM, WHICH NOT COMPATIBLE WITH THE PRIMARY SOLVENT, TO PROMOTE FORMATION OF AN EXTRACTED CAPROLACTAM-CONTAINING SECONDARY SOLUTION, WHEREBY PRECIPITATION PHENOMENA IS PROMOTED, AND THEN SEPARATING THE CAPROLACTAM-CONTAINING SECONDARY SOLUTION FROM THE MIXTURE OF THE PRIMARY SOLVENT AND THE COMPOUND COMPATIBLE THEREWITH, AND
Claim 2
Independent Claim
116 words
A METHOD FOR THE PREPARATION OF A PURE CAPROLACTAM FROM A DILUTED ACIDIC SOLUTION THEREOF, COMPRISING FIRST EXTRACTING THE CAPROLACTAM FROM THE SAID DILUTED ACIDIC SOLUTION THEREOF WITH A PRIMARY SUBSTITUTED PHENOL SOLVENT TO FORM A CAPROLACTAM-CONTAINING PRIMARY SOLUTION, SUPPLEMENTING SAID PRIMARY SOLUTION WITH A COMPOUND COMPATIBLE WITH SAID PRIMARY SOLVENT, AND SELECTED FROM THE GROUP CONSISTING OF CYCLOHEXANE, TOLUENE, BENZENE, AND ALIPHATIC, AROMATIC AND CHLORINATED HYDROCARBONS, AND WITH A SECONDARY SOLVENT FOR THE CAPROLACTAM, WHICH NOT COMPATIBLE WITH THE PRIMARY SOLVENT, TO PROMOTE FORMATION OF AN EXTRACTED CAPROLACTAM-CONTAINING SECONDARY SOLUTION, WHEREBY PRECIPITATION PHENOMENA IS PROMOTED, AND THEN SEPARATING THE CAPROLACTAM-CONTAINING SECONDARY SOLUTION FROM THE MIXTURE OF THE PRIMARY SOLVENT AND THE COMPOUND COMPATIBLE THEREWITH, AND
Claim 3
Dependent Claim
64 words
A method as claimed in claim 1, wherein the separation of the caprolactam is carried out in a single step process by adding to said primary solution a mixture of said compound which acts as a secondary solvent but which is incompatible with the primary solvent and the compound which is compatible with and a solvent for the primary solvent but not for caprolactam.
Claim 4
Dependent Claim
26 words
A method according to claim 1, wherein the primary solvent is a phenol substituted by at least an aliphatic substituent having at least three carbon atoms.
Claim 5
Dependent Claim
15 words
A method according to claim 1, wherein the secondary solvent for the lactam is water.
Claim 6
Dependent Claim
61 words
A method according to claim 1, wherein the addition to the primary solution of the secondAry solvent for the lactam and the solvent for the primary solvent are carried out simultaneously in a liquid-liquid extraction apparatus from which there are obtained the secondary solution of the lactam and a mixture of the primary solvent and of the solvent for the latter.
Claim 7
Dependent Claim
22 words
A method according to claim 1, wherein the operations described therein are preceded by a concentration of the primary solution by evaporation.
Claim 8
Dependent Claim
43 words
A method according to claim 1, wherein the primary solution of caprolactam is obtained by extraction of the primary solvent for caprolactam from acidic reaction mixtures as obtained by Beckmann rearrangement of cyclohexanoneoxime and by nitrosation in an acidic medium of cycloaliphatic compounds.
Claim 9
Dependent Claim
97 words
A method according to claim 3, wherein the lactam in the form of a dilute acidic solution is first extracted with said substituted phenol solvent, and after extraction the mixture is distilled to remove a part of the alkylated phenolic solvent, and then the impure caprolactam residue is mixed with cyclohexane and water, and the aqueous layer is then successively extracted with cyclohexane and the cyclohexane layer is successively extracted with water, then the cyclohexane is distilled off from the combined cyclohexane phases and the water is distilled off from the combined aqueous phases to obtain caprolactam.
References Cited (Backward Citations)
US2737511A
Cited
US3145198A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-08 | 1979-03-10 | 1979-09-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-08 | 1983-03-10 | 1983-09-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-08 | 1987-03-10 | 1987-09-09 | $7700.00 | Window Closed / Lapsed |