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US4363704A
Expired / Lapsed
US
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Separation of toluene from non-aromatic hydrocarbons by extractive distillation
Assignee: Individual
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Filing: 1981-11-20
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Granted: 1982-12-14
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Expires: 2001-11-20
Abstract
Abstract Toluene is virtually impossible to separate from similar boiling non-aromatic hydrocarbons by conventional rectification or distillation. Toluene can be readily separated from similar boiling non-aromatic hydrocarbons by using extractive distillation in which the extractive agent is a mixture of phthalic anhydride and/or maleic anhydride plus a suitable solvent. A typical mixture comprises phthalic anhydride, maleic anhydride and glycerol triacetate.
Inventors
- 👤 Lloyd Berg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 17:02
CPC Classifications
C; C07; C07C; C07C63/00; C07C63/14; C07C63/15; C07C63/16; C07C57/00; C07C57/02; C07C57/13; C07C57/145; C07C7/00; C07C7/04; C07C7/05; C07C7/08
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
90 words
A method for separating toluene from close boiling non-aromatic hydrocarbons which comprises distilling a mixture of toluene and close boiling non-aromatic hydrocarbons in a rectification column in the presence of an effective amount of an extractive agent sufficient to provide a relative volatility of 2.5 or greater comprising effective proportions of phthalic anhydride and/or maleic anhydride and a solvent from the group consisting of glycerol triacetate, dimethylformamide, ethyl acetoacetate, acetonyl acetone, acetophenone, 2,4-pentanedione, ethylene glycol phenyl ether, dichlorodiethyl ether, dimethylacetamide, benzophenone, ethylene glycol diacetate, furfural, nitrobenzene, 2-nitrotoluene, sulfolane, phenol, dimethylsulfoxide.
Claim 2
Independent Claim
90 words
A method for separating toluene from close boiling non-aromatic hydrocarbons which comprises distilling a mixture of toluene and close boiling non-aromatic hydrocarbons in a rectification column in the presence of an effective amount of an extractive agent sufficient to provide a relative volatility of 2.5 or greater comprising effective proportions of phthalic anhydride and/or maleic anhydride and a solvent from the group consisting of glycerol triacetate, dimethylformamide, ethyl acetoacetate, acetonyl acetone, acetophenone, 2,4-pentanedione, ethylene glycol phenyl ether, dichlorodiethyl ether, dimethylacetamide, benzophenone, ethylene glycol diacetate, furfural, nitrobenzene, 2-nitrotoluene, sulfolane, phenol, dimethylsulfoxide.
Claim 3
Dependent Claim
23 words
The method of claim 1 in which the extractive agent is phthalic anhydride and a solvent from the group listed in claim 1.
Claim 4
Dependent Claim
23 words
The method of claim 1 in which the extractive agent is maleic anhydride and a solvent from the group listed in claim 1.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-12-13 | 1986-06-14 | 1986-12-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-12-13 | 1990-06-14 | 1990-12-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-12-13 | 1994-06-14 | 1994-12-14 | $7700.00 | Window Closed / Lapsed |