US4585526A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Separation of m-xylene from o-xylene by extractive distillation
Assignee: Individual
•
Filing: 1984-10-01
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Granted: 1986-04-29
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Expires: 2004-10-01
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 comprises propoxypropanol; propoxypropanol and 1,4-butanediol; ethyl benzoate and ethylene glycol phenyl ether and benzyl alcohol.
Inventors
- 👤 Lloyd Berg
- 👤 An-I Yeh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 14:36
CPC Classifications
C; C07; C07C; C07C7/00; C07C7/04; C07C7/05; C07C7/08
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
56 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 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 comprises propoxypropanol.
Claim 2
Independent Claim
56 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 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 comprises propoxypropanol.
Claim 3
Dependent Claim
33 words
The method of claim 1 in which the extractive agent comprises a mixture of propoxypropanol and at least one of the group consisting essentially of: propylene glycol, 1,4-butanediol, 1,5-pentanediol, hexylene glycol, diethylene glycol.
References Cited (Backward Citations)
US2721170A
Cited
US2456561A
Cited
GB736856A
Cited
US2957811A
Cited
US3089829A
Cited
US3114784A
Cited
GB1020175A
Cited
US3328267A
Cited
GB1151606A
Cited
US4299668A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-04-28 | 1989-10-28 | 1990-04-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-04-28 | 1993-10-28 | 1994-04-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-04-28 | 1997-10-28 | 1998-04-29 | $7700.00 | Window Closed / Lapsed |