US3773846A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the production of high purity meta-xylene
Assignee: Universal Oil Products Co
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Filing: 1972-08-07
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Granted: 1973-11-20
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Expires: 1992-08-07
Abstract
Abstract HIGH PURITY META-XYLENE, ALONG WITH HIGH PURITY PARAXYLENE AND, IF DESIRED, HIGH PURITY ORTHO-XYLENE, IS RECOVERED AND PRODUCED FROM A C8 AROMATIC MIXTURE CONTAINING THE XYLENE ISOMERS AND ETHYL-BENZENE BY A COMBINATION OF FRACTIONATION, SELECTIVE ADSORPTION, FRACTIONAL CRYSTALLIZATION, AND ISOMERIZATION. THE UNIQUE COMBINATION ALLOWS THE RECOVERY OF HIGH PURITY META-XYLENE BY REDUCING THE CONCENTRATION OF PARA-XYLENE AND ORTHO-XYLENE IN THE FEED TO THE META-XYLENE CRYSTALLIZER BELOW THAT OF THE PARA-XYLENE/META-XYLENE EUTECTIC MIXTURE AND THE ORTHOXYLENE/META-XYLENE CUTECTIC MIXTURE.
Inventors
- 👤 C Berger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 09:00
CPC Classifications
C; C07; C07C; C07C7/00; C07C7/005; C07C7/12; C07C7/13
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-11-19 | 1977-05-21 | 1977-11-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-19 | 1981-05-21 | 1981-11-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-19 | 1985-05-21 | 1985-11-20 | $7700.00 | Window Closed / Lapsed |