Patent US5453167A successfully refreshed from Google Patents.
US5453167A
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Separation of xylenes by extractive distillation
Assignee: Individual
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Filing: 1995-04-07
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Granted: 1995-09-26
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Expires: 2015-04-07
Abstract
Abstract p-Xylene cannot be separated from m-xylene by distillation or rectification because of the proximity of their boiling points. p-Xylene can be separated from m-xylene by means of extractive distillation. Effective agents are 3-ethylphenol and isopropyl palmitate. Effective agents for separating mixtures of p-xylene, m-xylene and o-xylene are 2-butoxyethyl acetate and 1,1,1-trichloroethane.
Inventors
- 👤 Lloyd Berg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 14:49
CPC Classifications
C; C07; C07C; C07C7/00; C07C7/04; C07C7/05; C07C7/08
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
95 words
A method for recovering p-xylene from a mixture of p-xylene and m-xylene which comprises distilling a mixture of p-xylene and m-xylene in the presence of from one to ten parts by weight of an extractive agent per part of p-xylene-m-xylene mixture, recovering the p-xylene as overhead product and obtaining the m-xylene and the extractive agent as bottoms product, wherein said extractive agent consists of one material selected from the group consisting of o-cresol, 3-ethyl phenol, 2,4-dimethyl phenol, 2,6-dimethyl phenol, 2-nitro phenol, 4-nitro phenol, isopropyl palmitate, 3-methoxy ethyl cyano acetate, methyl salicylate and n-butyl cyano acetate.
Claim 2
Independent Claim
95 words
A method for recovering p-xylene from a mixture of p-xylene and m-xylene which comprises distilling a mixture of p-xylene and m-xylene in the presence of from one to ten parts by weight of an extractive agent per part of p-xylene-m-xylene mixture, recovering the p-xylene as overhead product and obtaining the m-xylene and the extractive agent as bottoms product, wherein said extractive agent consists of one material selected from the group consisting of o-cresol, 3-ethyl phenol, 2,4-dimethyl phenol, 2,6-dimethyl phenol, 2-nitro phenol, 4-nitro phenol, isopropyl palmitate, 3-methoxy ethyl cyano acetate, methyl salicylate and n-butyl cyano acetate.
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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) | 1998-09-25 | 1999-03-27 | 1999-09-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-09-25 | 2003-03-27 | 2003-09-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-09-25 | 2007-03-27 | 2007-09-26 | $7700.00 | Window Closed / Lapsed |