Patent US5819155A successfully refreshed from Google Patents.
Patent US4676872A successfully refreshed from Google Patents.
US4676872A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Separation of m-xylene from o-xylene by extractive distillation with adiponitrile and mixtures thereof
Assignee: Individual
•
Filing: 1986-04-21
•
Granted: 1987-06-30
•
Expires: 2006-04-21
Abstract
Abstract m-Xylene is difficult to separate from o-xylene by conventional distillation or rectification 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 is adiponitrile or a mixture of it with certain high boiling organic compounds. Typical examples of effective agents are: adiponitrile; adiponitrile and 1,4-butanediol; adiponitrile, ethylene carbonate and benzyl alcohol.
Inventors
- 👤 Lloyd Berg
- 👤 An-I Yeh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 16:01
CPC Classifications
C; C07; C07C; C07C7/00; C07C7/04; C07C7/05; C07C7/08
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
61 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 about one part of extractive agent per part of x-xylene-o-xylene mixture, recovering m-xylene as overhead product and obtaining the extractive agent and o-xylene from the stillpot, the extractive agent consists of adiponitrile.
Claim 2
Independent Claim
61 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 about one part of extractive agent per part of x-xylene-o-xylene mixture, recovering m-xylene as overhead product and obtaining the extractive agent and o-xylene from the stillpot, the extractive agent consists of adiponitrile.
Claim 3
Independent Claim
113 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 recitification column in the presence of about one part of extractive agent per part of m-xylene-o-xylene mixture, recovering m-xylene as overhead product and obtaining the extractive agent and o-xylene from the stillpot, the extractive agent consists of adipontrile and at least one material from the group consisting of diethylene glycol, hydroquinone, nitrobenzene, tetraethylene glycol, benzyl butyl phthalate, methyl p-hydroxybenzoate, ethylene glycol phenyl ether, bis phenol-A, benzyl alcohol, butyl benzoate, dimethyl phthalate, diphenyl isophthalate, diethyl phthalate, dihexyl phthalate, triisononyl mellitate, ethyl acetoacetate, propylene glycol, methyl benzyl alcohol and butyl cyclohexyl phthalate.
Claim 4
Independent Claim
113 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 recitification column in the presence of about one part of extractive agent per part of m-xylene-o-xylene mixture, recovering m-xylene as overhead product and obtaining the extractive agent and o-xylene from the stillpot, the extractive agent consists of adipontrile and at least one material from the group consisting of diethylene glycol, hydroquinone, nitrobenzene, tetraethylene glycol, benzyl butyl phthalate, methyl p-hydroxybenzoate, ethylene glycol phenyl ether, bis phenol-A, benzyl alcohol, butyl benzoate, dimethyl phthalate, diphenyl isophthalate, diethyl phthalate, dihexyl phthalate, triisononyl mellitate, ethyl acetoacetate, propylene glycol, methyl benzyl alcohol and butyl cyclohexyl phthalate.
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) | 1990-06-29 | 1990-12-29 | 1991-06-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-06-29 | 1994-12-29 | 1995-06-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-06-29 | 1998-12-29 | 1999-06-30 | $7700.00 | Window Closed / Lapsed |