US4650851A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Purification of glycolide
Assignee: Deknatel Technology Corp
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Filing: 1986-03-19
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Granted: 1987-03-17
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Expires: 2006-03-19
Abstract
Abstract A process for the purification of glycolide which comprises dissolving the glycolide to be purified in a suitable organic solvent, adding alumina to the resulting solution to form a slurry wherein the alumina is in intimate contact with the dissolved glycolide, stirring the slurry under controlled conditions for a period of 1 to 60 minutes, and filtering to remove the alumina and, if desired, evaporating to remove the solvent and recovering the purified glycolide; and the production of suture-grade polyglycolic acid by the polymerization of the resulting purified glycolide.
Inventors
- 👤 David Rhum
- 👤 Richard S. Matthews
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:50
CPC Classifications
C; C08; C08F; C08F6/00; C08F6/14; C08F6/16; C08G; C08G63/00; C08G63/02; C08G63/06; C08G63/08; C07; C07D; C07D319/00; C07D319/10; C07D319/12
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
71 words
A process for the purification of glycolide which comprises dissolving the glycolide to be purified in a suitable organic solvent, adding alumina to the resulting solution to form a slurry wherein the alumina is in intimate contact with the dissolved glycolide, stirring the slurry under controlled conditions for a period of 1 to 60 minutes, and filtering to remove the alumina, evaporating to remove the solvent and recording the purified glycolide.
Claim 2
Dependent Claim
71 words
A process for the purification of glycolide which comprises dissolving the glycolide to be purified in a suitable organic solvent, adding alumina to the resulting solution to form a slurry wherein the alumina is in intimate contact with the dissolved glycolide, stirring the slurry under controlled conditions for a period of 1 to 60 minutes, and filtering to remove the alumina, evaporating to remove the solvent and recording the purified glycolide.
Claim 3
Dependent Claim
39 words
A process according to claim 1, in which the ratio of glycolide to alumina is from 1:0.01 to 1:10, by weight and said controlled conditions are such that the amount of alumina used is correlated to the contact time.
Claim 4
Dependent Claim
14 words
A process according to claim 1, in which the organic solvent is methylene chloride.
Claim 5
Dependent Claim
13 words
A process according to claim 1, in which the organic solvent is tetrahydrofuran.
Claim 6
Dependent Claim
17 words
A process according to claim 1, in which the steps are conducted under a dry inert atmosphere.
Claim 7
Dependent Claim
13 words
A process according to claim 5, in which the inert atmosphere is nitrogen.
Claim 8
Dependent Claim
78 words
A process for the purification of glycolide according to claim 1, which comprises dissolving about one part by weight of the glycolide to be purified in methylene chloride, adding to the resulting glycolide solution about 0.1 part by weight of granulated alumina and stirring the resultant slurry for about 30 minutes, filtering to remove the alumina, evaporating the methylene chloride and drying the wet, purified glycolide so obtained under vacuum at a temperature of 45° to 50° C.
Claim 9
Dependent Claim
18 words
A process according to claim 7, in which the complete process is conducted under a dry inert atmosphere.
Claim 10
Dependent Claim
13 words
A process according to claim 8, in which the inert atmosphere is nitrogen.
Claim 11
Dependent Claim
23 words
A process for the production of suture-grade polyglycolic acid which comprises polymerizing the purified glycolide prepared by the process according to claim 1.
References Cited (Backward Citations)
US3297033A
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US3463158A
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US3442871A
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US3457280A
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US3435008A
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US3763190A
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US4387264A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-03-16 | 1990-09-15 | 1991-03-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-03-16 | 1994-09-15 | 1995-03-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-03-16 | 1998-09-15 | 1999-03-17 | $7700.00 | Window Closed / Lapsed |