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US4140741A
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Use of cyclic carbonic acid esters as solvents for poly-(β-hydroxybutyric acid)
Assignee: Agroferm AG
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Filing: 1978-01-12
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Granted: 1979-02-20
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Expires: 1998-01-12
Abstract
Abstract The use of cyclic carbonic acid esters of the formula: ##STR1## wherein R 1 , R 2 , R 3 and R 4 , which may be the same or different, are hydrogen or alkyl with 1 to 6 C-atoms, as a solvent for racemic or optically active poly-(β-hydroxybutyric acid). The preferred embodiment uses hot (120 to 150° C) ethylene carbonate or 1,2-propylene carbonate to extract poly-(β-hydroxybutyric acid) from moist or dry fermentation masses. These solvents have the advantage that the extracted poly-(β-hydroxybutyric acid) is precipitated in good yield from them on cooling. In addition they may be recycled without the need for a solvent regeneration step. These cyclic carbonic acid esters may also be used as the solvent in the processing of poly-(β-hydroxybutyric acid) by e.g. wet spinning.
Inventors
- 👤 Robert M. Lafferty
- 👤 Elmar Heinzle
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 05:56
CPC Classifications
C; C12; C12P; C12P7/00; C12P7/62; C12P7/625; C08; C08G; C08G63/00; C08G63/02; C08G63/06; C08G63/88; C08G63/89
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
109 words
A process which comprises: extracting poly-(β-hydroxybutyric acid) from a moist or dry cell mass of a microorganism which forms poly-(β-hydroxybutyric acid) by suspending the cell mass in a liquid cyclic carbonic acid ester of the formula: ##STR3## wherein R 1 , R 2 , R 3 and R 4 , which are the same or different, are hydrogen or alkyl with 1 to 6 carbon atoms, as a solvent for the poly-(β-hydroxybutyric acid), heating the suspension with stirring to a temperature above 100° C., separating the cell mass from the hot solvent extract, cooling the hot solvent extract to precipitate poly-(β-hydroxybutyric acid), and wet spinning the precipitated poly-(β-hydroxybutyric acid).
Claim 2
Dependent Claim
109 words
A process which comprises: extracting poly-(β-hydroxybutyric acid) from a moist or dry cell mass of a microorganism which forms poly-(β-hydroxybutyric acid) by suspending the cell mass in a liquid cyclic carbonic acid ester of the formula: ##STR3## wherein R 1 , R 2 , R 3 and R 4 , which are the same or different, are hydrogen or alkyl with 1 to 6 carbon atoms, as a solvent for the poly-(β-hydroxybutyric acid), heating the suspension with stirring to a temperature above 100° C., separating the cell mass from the hot solvent extract, cooling the hot solvent extract to precipitate poly-(β-hydroxybutyric acid), and wet spinning the precipitated poly-(β-hydroxybutyric acid).
Claim 3
Dependent Claim
16 words
A process according to claim 1 in which the poly-(β-hydroxybutyric acid) is the dextro optical isomer.
Claim 4
Dependent Claim
78 words
A process which comprises: preparing a solution of poly-(β-hydroxybutyric acid) in a cyclic carbonic acid ester solvent, or mixture thereof, of the formula ##STR4## wherein R 1 , R 2 , R 3 and R 4 , which may be the same or different, are hydrogen or alkyl with 1 to 6 carbon atoms, and wet spinning the solution through a nozzle into an aqueous bath mixture containing at least one of the solvents of the above formula.
Claim 5
Dependent Claim
78 words
A process which comprises: preparing a solution of poly-(β-hydroxybutyric acid) in a cyclic carbonic acid ester solvent, or mixture thereof, of the formula ##STR4## wherein R 1 , R 2 , R 3 and R 4 , which may be the same or different, are hydrogen or alkyl with 1 to 6 carbon atoms, and wet spinning the solution through a nozzle into an aqueous bath mixture containing at least one of the solvents of the above formula.
Claim 6
Dependent Claim
19 words
A process according to claim 3 in which the solvent is ethylene carbonate, 1,2-propylene carbonate or a mixture thereof.
Claim 7
Dependent Claim
91 words
A process for wet spinning chemically synthesized racemic or optically active poly-(β-hydroxybutyric acid) which comprises: dissolving said poly-(β-hydroxybutyric acid) in a liquid cyclic carbonic acid ester of the formula: ##STR5## wherein R 1 , R 2 , R 3 and R 4 , which are the same or different, are hydrogen or alkyl with 1 to 6 carbon atoms, and spinning the solution thus obtained through a nozzle into a precipitating bath consisting of about 50% by vol. water and about 50% by vol. of said liquid cyclic carbonic acid ester.
Claim 8
Dependent Claim
91 words
A process for wet spinning chemically synthesized racemic or optically active poly-(β-hydroxybutyric acid) which comprises: dissolving said poly-(β-hydroxybutyric acid) in a liquid cyclic carbonic acid ester of the formula: ##STR5## wherein R 1 , R 2 , R 3 and R 4 , which are the same or different, are hydrogen or alkyl with 1 to 6 carbon atoms, and spinning the solution thus obtained through a nozzle into a precipitating bath consisting of about 50% by vol. water and about 50% by vol. of said liquid cyclic carbonic acid ester.
Claim 9
Dependent Claim
19 words
A process according to claim 5 in which the solvent is ethylene carbonate, 1,2-propylene carbonate or a mixture thereof.
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) | 1982-02-19 | 1982-08-21 | 1983-02-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-02-19 | 1986-08-21 | 1987-02-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-02-19 | 1990-08-21 | 1991-02-20 | $7700.00 | Window Closed / Lapsed |