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US4079045A
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Esterification of terephthalic acid with an alkylene glycol in the presence of a pyridine dicarboxylic acid compound
Assignee: Honeywell International Inc
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Filing: 1976-06-30
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Granted: 1978-03-14
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Expires: 1996-06-30
Abstract
Abstract The esterification of an aromatic dicarboxylic acid with an alkylene glycol containing 2 to 10 carbon atoms is described under conditions of direct esterification wherein the resultant polyester has low ether content. The dicarboxylic acid is esterified with the alkylene glycol in the presence of a compound of the formula <IMAGE> wherein M is H, an alkali metal selected from the group consisting of lithium, sodium and potassium or an alkaline earth metal selected from the group calcium and magnesium.
Inventors
- 👤 Stanley David Lazarus
- 👤 Joseph Donald DeCaprio
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 11:53
CPC Classifications
C; C08; C08G; C08G63/00; C08G63/68; C08G63/685; C08G63/6854; C08G63/6856; C08G63/78; C08G63/82
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
131 words
A process for the preparation of a linear high molecular weight fiber forming polyester which comprises esterifying terephthalic acid with ethylene glycol under direct esterification conditions in an inert atmosphere at a pressure of at least atmospheric and in the presence of from about 0.25 to about 1.0 weight percent based on the weight of the terephthalic acid, of a heterocyclic compound selected from the group consisting of pyridine dicarboxylic acid (2,4), pyridine dicarboxylic acid (2,5), pyridine dicarboxylic acid (2,6) and pyridine dicarboxylic acid (3,5), the molecular ratio of total acid to glycol in said esterification being between 1.0:1.1 and 1.0:1.7, the temperature range being between about 200° to about 300° C., whereby the diethylene glycol incorporated into the polyester is significantly reduced and the dyeability of the polyester is improved.
Claim 2
Dependent Claim
131 words
A process for the preparation of a linear high molecular weight fiber forming polyester which comprises esterifying terephthalic acid with ethylene glycol under direct esterification conditions in an inert atmosphere at a pressure of at least atmospheric and in the presence of from about 0.25 to about 1.0 weight percent based on the weight of the terephthalic acid, of a heterocyclic compound selected from the group consisting of pyridine dicarboxylic acid (2,4), pyridine dicarboxylic acid (2,5), pyridine dicarboxylic acid (2,6) and pyridine dicarboxylic acid (3,5), the molecular ratio of total acid to glycol in said esterification being between 1.0:1.1 and 1.0:1.7, the temperature range being between about 200° to about 300° C., whereby the diethylene glycol incorporated into the polyester is significantly reduced and the dyeability of the polyester is improved.
Claim 3
Dependent Claim
14 words
The process of claim 1 wherein said heterocyclic compound is pyridine dicarboxylic acid (2,5).
Claim 4
Dependent Claim
14 words
The process of claim 1 wherein said heterocyclic compound is pyridine dicarboxylic acid (2,6).
Claim 5
Dependent Claim
32 words
The process of claim 1 wherein said direct esterification is carried out in the presence of about 0.5 weight percent based on the weight of said terephthalic acid, of said heterocyclic compound.
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) | 1981-03-13 | 1981-09-12 | 1982-03-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-03-13 | 1985-09-12 | 1986-03-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-03-13 | 1989-09-12 | 1990-03-14 | $7700.00 | Window Closed / Lapsed |