US4299668A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Separation of ethylbenzene from para- and meta-xylenes by extractive distillation
Assignee: International Synthetic Rubber Co Ltd
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Filing: 1981-02-23
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Granted: 1981-11-10
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Expires: 2001-02-23
Abstract
Abstract Ethylbenzene and para-xylene and/or meta-xylene are difficult to separate by distillation because they boil only 2.3 C.° and 3.1 C.° apart. Ethylbenzene can be readily separated from the xylenes by using extractive distillation in which the extractive distillation agent is a mixture of pentachlorophenol admixed with certain chlorinated and/or oxygenated organic compounds boiling higher than the xylenes. A typical mixture comprises pentachlorophenol, benzene hexachloride and 1,2,4-trichlorobenzene.
Inventors
- 👤 Lloyd Berg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 14:42
CPC Classifications
C; C07; C07C; C07C7/00; C07C7/04; C07C7/05; C07C7/08
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
67 words
A method for separating ethylbenzene from p-xylene and/or m-xylene which comprises distilling in a substantially anhydrous condition a mixture of ethylbenzene, p-xylene and/or m-xylene in a rectification column in the presence of an effective amount of an extractive agent comprising pentachlorophenol and one or more other compounds drawn from the group comprising 2,4-dichlorotoluene, 1,2,4-trichlorobenzene, 1,2,4,5-tetrachlorobenzene, polychlorobenzenes (a mixture of tetra- and pentachlorobenzenes), benzene hexachloride, 2,3,4,6-tetrachlorophenol, 1,2,3-trichloropropane, n-butoxyethanol.
Claim 2
Independent Claim
67 words
A method for separating ethylbenzene from p-xylene and/or m-xylene which comprises distilling in a substantially anhydrous condition a mixture of ethylbenzene, p-xylene and/or m-xylene in a rectification column in the presence of an effective amount of an extractive agent comprising pentachlorophenol and one or more other compounds drawn from the group comprising 2,4-dichlorotoluene, 1,2,4-trichlorobenzene, 1,2,4,5-tetrachlorobenzene, polychlorobenzenes (a mixture of tetra- and pentachlorobenzenes), benzene hexachloride, 2,3,4,6-tetrachlorophenol, 1,2,3-trichloropropane, n-butoxyethanol.
Claim 3
Dependent Claim
15 words
The method of claim 1 in which the extractive agent is pentachlorophenol, 2,3,4,6-tetrachlorophenol and 1,2,4-trichlorobenzene.
Claim 4
Dependent Claim
15 words
The method of claim 1 in which the extractive agent is pentachlorophenol, 2,3,4,6-tetrachlorophenol and 2,4-dichlorotoluene.
Claim 5
Dependent Claim
16 words
The method of claim 1 in which the extractive agent is pentachlorophenol, benzene hexachloride and 2,4-dichlorotoluene.
Claim 6
Dependent Claim
16 words
The method of claim 1 in which the extractive agent is pentachlorophenol, polychlorobenzenes, 1,2,4,5-tetrachlorobenzene and n-butoxyethanol.
Claim 7
Dependent Claim
16 words
The method of claim 1 in which the extractive agent is pentachlorophenol, polychlorobenzenes 1,2,4,5-tetrachlorobenzene and 2,4-dichlorotoluene.
Claim 8
Dependent Claim
17 words
The method of claim 1 in which the extractive agent is pentachlorophenol, polychlorobenzenes, benzene hexachloride and 1,2,4-trichlorobenzene.
Claim 9
Dependent Claim
15 words
The method of claim 1 in which the extractive agent is pentachlorophenol, polychlorobenzenes and 1,2,4-trichlorobenzene.
Claim 10
Dependent Claim
15 words
The method of claim 1 in which the extractive agent is pentachlorophenol, polychlorobenzenes and 1,2,3-trichloropropane.
Claim 11
Dependent Claim
16 words
The method of claim 1 in which the extractive agent is pentachlorophenol, benzene hexachloride and 1,2,4-trichlorobenzene.
Claim 12
Dependent Claim
16 words
The method of claim 1 in which the extractive agent is pentachlorophenol, polychlorobenzenes and benzene hexachloride.
Claim 13
Dependent Claim
14 words
The method of claim 1 in which the extractive agent is pentachlorophenol and 2,3,4,6-tetrachlorophenol.
References Cited (Backward Citations)
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US2532031A
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US2567228A
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US2799629A
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US3105017A
Cited
US3356593A
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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) | 1984-11-09 | 1985-05-11 | 1985-11-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-11-09 | 1989-05-11 | 1989-11-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-11-09 | 1993-05-11 | 1993-11-10 | $7700.00 | Window Closed / Lapsed |