US4264501A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the recovery of pyrrolidone-2
Assignee: Stamicarbon BV
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Filing: 1978-05-04
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Granted: 1981-04-28
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Expires: 1998-05-04
Abstract
Abstract A process is described for the recovery of 2-pyrrolidone monomer from polypyrrolidone waste material by heating the latter in the presence of a small amount of strong acid, and distilling off the said monomer.
Inventors
- 👤 Edmond H. J. P. Bour
- 👤 Sijbrandus E. Schaafsma
- 👤 Jean M. M. Warnier
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 16:08
CPC Classifications
C; C07; C07D; C07D201/00; C07D201/02; C07D201/12
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
73 words
A process for the recovery of 2-pyrrolidone monomer from polypyrrolidone starting materials which consists essentially in treating said starting materials with from about 0.05 to about 10 percent by weight of the polypyrrolidone, an inorganic or organic acid compound having a boiling point of at least 225° C., then heating at a temperature between about 200° C. and the melting point of said starting material and recovering the resultant pyrrolidone-2 monomer by distillation.
Claim 2
Dependent Claim
73 words
A process for the recovery of 2-pyrrolidone monomer from polypyrrolidone starting materials which consists essentially in treating said starting materials with from about 0.05 to about 10 percent by weight of the polypyrrolidone, an inorganic or organic acid compound having a boiling point of at least 225° C., then heating at a temperature between about 200° C. and the melting point of said starting material and recovering the resultant pyrrolidone-2 monomer by distillation.
Claim 3
Dependent Claim
20 words
Process according to claim 1, wherein said treatment is effected at a pressure of between about 0.5 and 1.0 bar.
Claim 4
Dependent Claim
26 words
Process according to claim 1, wherein said acid compound is used in an amount of between about 0.1 and 5.0% by weight, based on the polypyrrolidone.
Claim 5
Dependent Claim
39 words
Process according to claim 1, wherein said acid compound is selected from the group consisting of phosphoric acid, phosphorous acid, boric acid, sulphuric acid, mono- and bi-cyclic aromatic sulphonic acids and aliphatic and aromatic mono-, di- and tri-carboxylic acids.
Claim 6
Dependent Claim
12 words
Process according to claim 1, wherein said acid compound is phosphoric acid.
Claim 7
Dependent Claim
93 words
Process for the recovery of 2-pyrrolidone monomer from polypyrrolidone starting materials, wherein said starting material is heated to a temperature of between 200° C. and the melting point of the starting material at a pressure of between 0.5 and 0.95 bar in the presence of between 0.1 and 10% weight of a strong inorganic acid, having a boiling point of at least 225° C. the reaction mixture being heated by the introduction of superheated steam therein, and recovering 2-pyrrolidone as an aqeous solution by condensation of the vapor mixture, optionally under rectifying conditions.
Claim 8
Dependent Claim
93 words
Process for the recovery of 2-pyrrolidone monomer from polypyrrolidone starting materials, wherein said starting material is heated to a temperature of between 200° C. and the melting point of the starting material at a pressure of between 0.5 and 0.95 bar in the presence of between 0.1 and 10% weight of a strong inorganic acid, having a boiling point of at least 225° C. the reaction mixture being heated by the introduction of superheated steam therein, and recovering 2-pyrrolidone as an aqeous solution by condensation of the vapor mixture, optionally under rectifying conditions.
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) | 1984-04-27 | 1984-10-27 | 1985-04-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-04-27 | 1988-10-27 | 1989-04-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-04-27 | 1992-10-27 | 1993-04-28 | $7700.00 | Window Closed / Lapsed |