US4488937A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Separation of m-xylene from o-xylene by extractive distillation
Assignee: Individual
•
Filing: 1984-04-11
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Granted: 1984-12-18
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Expires: 2004-04-11
Abstract
Abstract m-Xylene is difficult to separate from o-xylene by conventional rectification or distillation because of the close proximity of their boiling points. m-Xylene can be readily separated from o-xylene by using extractive distillation in which the extractive agent is ethyl-2-hydroxybenzoate; propoxypropanol puls 1,4-butanediol; sulfolane plus dimethylsulfoxide plus ethyl benzoate.
Inventors
- 👤 Lloyd Berg
- 👤 An-I Yeh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 15:00
CPC Classifications
C; C07; C07C; C07C7/00; C07C7/04; C07C7/05; C07C7/08
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
60 words
A method for recovering m-xylene from a mixture of m-xylene and o-xylene which comprises distilling a mixture of m-xylene and o-xylene in a rectification column in the presence of an effective amount of an extractive agent, recovering essentially pure m-xylene as overhead product and obtaining the extractive agent and o-xylene from the stillpot or reboiler, the extractive agent includes sulfolane.
Claim 2
Independent Claim
60 words
A method for recovering m-xylene from a mixture of m-xylene and o-xylene which comprises distilling a mixture of m-xylene and o-xylene in a rectification column in the presence of an effective amount of an extractive agent, recovering essentially pure m-xylene as overhead product and obtaining the extractive agent and o-xylene from the stillpot or reboiler, the extractive agent includes sulfolane.
Claim 3
Dependent Claim
57 words
The method of claim 1 in which the extractive agent comprises a mixture of sulfolane and at least on of the group consisting essentially of: adiponitrile, dimethyl-2-hydroxybenzoate, maleic anhydride, phthalic anhydride, dimethylformamide, nitrobenzene, diethylene glycol, dibutyl phthalate, acetophenone, 1,4-butanediol, benzyl alcohol, benzyl, cyanide, methyl benzoate, ethyl benzoate, isophorone, benzoic acid, phenyl acetic acid, ethylene carbonate, propylene carbonate.
References Cited (Backward Citations)
US2721170A
Cited
CA639564A
Cited
CA659726A
Cited
US2456561A
Cited
US2738372A
Cited
US2880253A
Cited
US2957811A
Cited
US3116224A
Cited
US4024028A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-12-18 | 1988-06-18 | 1988-12-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-12-18 | 1992-06-18 | 1992-12-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-12-18 | 1996-06-18 | 1996-12-18 | $7700.00 | Window Closed / Lapsed |