US3892798A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for introducing terephthalic acid into a reaction
Assignee: Davy Ashmore AG
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Filing: 1972-09-11
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Granted: 1975-07-01
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Expires: 1992-09-11
Abstract
Abstract Terephthalic acid is introduced into a reaction zone maintained under a reaction pressure by compressing a powdered terephthalic acid, adding the compressed acid to a portion removed from the reaction in a ratio of about 1 to 33% by weight acid to removed portion, homogenizing the resultant mixture and returning it to the reaction zone.
Inventors
- 👤 Rudolf Heeg
- 👤 Alfred Striebich
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 17:32
CPC Classifications
C; C08; C08G; C08G63/00; C08G63/78; C08G63/785
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
157 words
IN A PROCESS FOR INTRODUCING POWDERED TEREPHTHALIC ACID INTO A REACTION MIXTURE OF TEREPHTHALIC ACID, PARTIALLY ESTERIFIED IED WITH ETHYLENE GLYCOL INA PRESSURIZED REACTION VESSEL IN AN ESTERIFICATION REACTION ZONE MAINTAINED AT SUPERATMOSPHERIC PRESSURE WHEREIN THE ETHYLENE GLYCOL IS INTRODUCED ONLY DIRECTLY INTO THE REACTION VESSEL, THE IMPROVED PROCESS FOR ADDING THE TEREPHTHALIC ACID TO THE REACTION MIXTURE WHICH COMPRISES REMOVING A PORTION OF THE REACTION MIXTURE FROM THE REACTION ZONE, RAISING THE PRESSURE OF THE POWERED TEREPHTHALIC ACID TO SUBSTANTIALLY THE PRESSURE OF THE REACTION ZONE, ADDING THE PRESSURIZED POWERED ACID TO THE REMOVED PORTION OF THE REACTION MIXTURE, WITHOUT INTERMEDIATE COOLING OF SAID REMOVED PORTION OF THE REACTION MIXTURE OR ETHYLENE GLYCOL ADDITION THERETO IN A QUANTITIVTIVE RATIO OF POWERED ACID TO REMOVED PORTION OF THE REACTION MIXTURE OF ABOUT 1 TO 33% BY WEIGHT, HOMOGENENIZING THE RESULTANT MIXTURE OF ABOUT 1 TO 33% BY AND RETURNING THE RESULTANT HOMOGENIZED MIXTURE TO THE REACTION MIXTURE.
Claim 2
Dependent Claim
157 words
IN A PROCESS FOR INTRODUCING POWDERED TEREPHTHALIC ACID INTO A REACTION MIXTURE OF TEREPHTHALIC ACID, PARTIALLY ESTERIFIED IED WITH ETHYLENE GLYCOL INA PRESSURIZED REACTION VESSEL IN AN ESTERIFICATION REACTION ZONE MAINTAINED AT SUPERATMOSPHERIC PRESSURE WHEREIN THE ETHYLENE GLYCOL IS INTRODUCED ONLY DIRECTLY INTO THE REACTION VESSEL, THE IMPROVED PROCESS FOR ADDING THE TEREPHTHALIC ACID TO THE REACTION MIXTURE WHICH COMPRISES REMOVING A PORTION OF THE REACTION MIXTURE FROM THE REACTION ZONE, RAISING THE PRESSURE OF THE POWERED TEREPHTHALIC ACID TO SUBSTANTIALLY THE PRESSURE OF THE REACTION ZONE, ADDING THE PRESSURIZED POWERED ACID TO THE REMOVED PORTION OF THE REACTION MIXTURE, WITHOUT INTERMEDIATE COOLING OF SAID REMOVED PORTION OF THE REACTION MIXTURE OR ETHYLENE GLYCOL ADDITION THERETO IN A QUANTITIVTIVE RATIO OF POWERED ACID TO REMOVED PORTION OF THE REACTION MIXTURE OF ABOUT 1 TO 33% BY WEIGHT, HOMOGENENIZING THE RESULTANT MIXTURE OF ABOUT 1 TO 33% BY AND RETURNING THE RESULTANT HOMOGENIZED MIXTURE TO THE REACTION MIXTURE.
Claim 3
Dependent Claim
60 words
A process according to claim 1 wherein the reaction zone comprises multiple reaction stages, each stage comprising a separate vessel for the esterification of terephthalic acid, and having a first and subsequent reaction stages and a partial stream is removed after the first esterification stage and, after addition of terephthalic acid and homogenization thereto is returned to this first stage.
Claim 4
Dependent Claim
87 words
A process according to claim 2 wherein after a stage subsequent to the first stage, a partial stream is removed, combined with the partial stream removed from the first esterification stage and the resultant mixture returned to the first stage, said process further characterized in that the partial stream from the first stage amounts to at least 50% of the sum of any partial streams from all the subsequent stages and the partial streams from the further stages are progressively smaller as the number of stages increases.
Claim 5
Dependent Claim
29 words
A process according to claim 3, wherein the partial streams from the subsequent esterification stages are pressurized to the pressure of the partial stream from the first esterification stage.
Claim 6
Dependent Claim
27 words
A process according to claim 1 wherein the pressure of the return mixture is increased during the homogenization to at least the pressure of the reaction mixture.
Claim 7
Dependent Claim
16 words
A process according to claim 1 wherein heat is supplied to the mixture during the homogenization.
Claim 8
Dependent Claim
36 words
A process according to claim 1 wherein less than 85% of the powdered terephthalic acid has a finest granule size less than 40 Mu and the balance has a granule size between 40 and 800 Mu
Claim 9
Dependent Claim
28 words
A process according to claim 1 wherein the terephthalic acid is added so that the final mixture has a ratio of acid between 1.6 and 25% by weight.
Claim 10
Dependent Claim
30 words
A process according to claim 1 wherein the terephthalic acid-containing mixture is homogenized through the use of rates of shear of 2.5 X 103 to 1.25 X 105 sec 1.
References Cited (Backward Citations)
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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) | 1978-06-30 | 1978-12-30 | 1979-07-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-30 | 1982-12-30 | 1983-07-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-30 | 1986-12-30 | 1987-07-01 | $7700.00 | Window Closed / Lapsed |