US5441608A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Separation of xylenes by extractive distillation
Assignee: Individual
•
Filing: 1994-05-23
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Granted: 1995-08-15
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Expires: 2014-05-23
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 1,1,2-trichloroethane. 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 18:04
CPC Classifications
C; C07; C07C; C07C7/00; C07C7/04; C07C7/05; C07C7/08
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
79 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, and 2,4-dimethyl phenol.
Claim 2
Independent Claim
79 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, and 2,4-dimethyl phenol.
Claim 3
Independent Claim
67 words
A method for recovering m-xylene from a mixture of m-xylene and p-xylene which comprises distilling a mixture of m-xylene and p-xylene in the presence of from one to ten parts by weight of an extractive agent per part of m-xylene--p-xylene mixture, recovering the m-xylene as overhead product and obtaining the p-xylene and the extractive agent as bottoms product, wherein said extractive agent consists of 1,1,1-trichloroethane or 1,1,2-trichloroethane.
Claim 4
Independent Claim
67 words
A method for recovering m-xylene from a mixture of m-xylene and p-xylene which comprises distilling a mixture of m-xylene and p-xylene in the presence of from one to ten parts by weight of an extractive agent per part of m-xylene--p-xylene mixture, recovering the m-xylene as overhead product and obtaining the p-xylene and the extractive agent as bottoms product, wherein said extractive agent consists of 1,1,1-trichloroethane or 1,1,2-trichloroethane.
Claim 5
Independent Claim
71 words
A method for recovering p-xylene from a mixture of p-xylene, m-xylene and o-xylene which comprises distilling a mixture of p-xylene, m-xylene and o-xylene in the presence of from one to ten parts by weight of an extractive agent per part of p-xylene--m-xylene--o-xylene mixture, recovering the p-xylene as overhead product and obtaining the m-xylene, o-xylene and the extractive agent as bottoms product, wherein said extractive agent consists of 2-butoxyethyl acetate or 1,1,1-trichloroethane.
Claim 6
Independent Claim
71 words
A method for recovering p-xylene from a mixture of p-xylene, m-xylene and o-xylene which comprises distilling a mixture of p-xylene, m-xylene and o-xylene in the presence of from one to ten parts by weight of an extractive agent per part of p-xylene--m-xylene--o-xylene mixture, recovering the p-xylene as overhead product and obtaining the m-xylene, o-xylene and the extractive agent as bottoms product, wherein said extractive agent consists of 2-butoxyethyl acetate or 1,1,1-trichloroethane.
Claim 7
Independent Claim
86 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 two materials selected from the group consisting of 3-ethyl phenol, 2-nitrophenol, 2,4-dimethyl phenol, 2,6-dimethyl phenol, 4-nitro-phenol, 2-butoxyethyl acetate and n-butyl cyano acetate.
Claim 8
Independent Claim
86 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 two materials selected from the group consisting of 3-ethyl phenol, 2-nitrophenol, 2,4-dimethyl phenol, 2,6-dimethyl phenol, 4-nitro-phenol, 2-butoxyethyl acetate 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) | 1998-08-14 | 1999-02-13 | 1999-08-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-08-14 | 2003-02-13 | 2003-08-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-08-14 | 2007-02-13 | 2007-08-15 | $7700.00 | Window Closed / Lapsed |