US4879044A
Expired / Lapsed
US
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Highly aromatic anisotropic polyurea/urethane membranes and their use for the separation of aromatics from non aromatics
Assignee: ExxonMobil Technology and Engineering Co
•
Filing: 1989-02-03
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Granted: 1989-11-07
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Expires: 2009-02-03
Abstract
Abstract An anisotropic elastomeric membrane preferably made from polyurea/urethane has been prepared. These anisotropic membranes are made from the corresponding polymeric material by preparing the polymeric material in a good solvent containing less than 5 vol % non-solvent, producing a film of the polymer solution on a support with a maximum pore size less than 20 microns, subjecting the film to conditions such that the solvent vapor pressure-time factor is 1000 mm Hg-min. or less, preferably 200 mm Hg-min or less, most preferably approaching 0 mm Hg-min and quenching the membrane film in a non-solvent yielding a three-layered anisotropic membrane. The preferred anisotropic membranes made from the polyurea/urethane copolymer, useful for the separation of aromatics from mixtures thereof with non-aromatics and saturates, in, for example, a naphtha feed stream, are characterized by possessing a urea index of at least about 20% but less than 100%, an aromatic carbon content of at least about 15 mole percent, a functional group density of at least about 10 per 1000 grams of polymer and a C=O/NH ratio of less than about 8.0.
Inventors
- 👤 Joseph L. Feimer
- 👤 Bernd A. Koenitzer
- 👤 Robert C. Schucker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 20:01
CPC Classifications
C; C10; C10G; C10G31/00; C10G31/11; B; B01; B01D; B01D63/00; B01D63/02; B01D67/00; B01D67/0002; B01D67/0009; B01D69/00; B01D69/12; B01D69/1216; B01D71/00; B01D71/06; B01D71/76; C08; C08G; C08G18/00; C08G18/06; C08G18/08; C08G18/10; B01D2325/00; B01D2325/02; B01D2325/022; B01D71/54
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
33 words
An anisotropic membrane: comprising layers of aromatic polyurea/urethane, including a thin dense layer, a thin non-continuous skin and an open porous structure between the aforesaid thin dense layer and the thin non-continuous skin.
Claim 2
Dependent Claim
33 words
An anisotropic membrane: comprising layers of aromatic polyurea/urethane, including a thin dense layer, a thin non-continuous skin and an open porous structure between the aforesaid thin dense layer and the thin non-continuous skin.
Claim 3
Dependent Claim
60 words
The anisotropic aromatic polyurea/urethane membrane of claim 1 further characterized in that it possesses a urea index of at least about 20% but less than 100%, an aromatic carbon content of at least about 15 mole %, a functional group density Σ(C═O+NH) per 1000 grams of polymer greater than about 10 and a C═O+NH ratio of less than about 8.
Claim 4
Dependent Claim
48 words
The anisotropic aromatic polyurea/urethane membrane of claim 2 wherein the urea index at least about 40% but less than 100% aromatic carbon content is at least about 20 mole %, the functiona group density is greater than about 12 and the C═O+NH ratio is less than about 5.
Claim 5
Independent Claim
30 words
A method comprising separating aromatics from a mixture of aromatics with non-aromatics-saturates by contacting the mixture with one side of an anisotropic aromatic polyurea/urethane membrane characterized by possessing three layers.
Claim 6
Independent Claim
30 words
A method comprising separating aromatics from a mixture of aromatics with non-aromatics-saturates by contacting the mixture with one side of an anisotropic aromatic polyurea/urethane membrane characterized by possessing three layers.
Claim 7
Dependent Claim
60 words
The method of claim 4 wherein the anisotropic aromatic polyurea/urethane membrane is characterized by possessing a urea index of at least about 20% but less than 100%, an aromatic carbon content of at least about 15 mole %, a functional group density Σ(C═O+NH) per 1000 grams polymer greater than about 10 and a C═O/NH ratio of less than about 8.
Claim 8
Dependent Claim
51 words
The method of claim 5 wherein the anisotropic aromatic polyurea/urethane membrane has a urea index of at least about 40% but less than 100%, an aromatic carbon content of at least about 20, a functional group density of greater than about 12 and a C═O/NH ratio of less than about 5.
Claim 9
Dependent Claim
87 words
The method of claim 4, 5 or 6 wherein the anisotropic polyurea/urethane membrane is made by preparing a polyurea/urethane copolymer in a good solvent which contains less than about 5 volume percent non-solvent to produce a casting solution, depositing a film of said casting solution on a support substrate having a maximum pore size of less than 20 microns, subjecting the film to conditions such that the solvent vapor pressure-time factor is about 1000 mm Hg-min or less, and quenching said film on a nonsolvent quenching medium.
Claim 10
Dependent Claim
47 words
The method of claim 7 wherein the high boiling solvent is dimethylformamide and contains about 0 volume percent non-solvent, the support substrate is non-porous glass, metal or release paper, the solvent vapor pressure-time factor is about 200 mm Hg-min. or less and the quenching medium is water.
Claim 11
Dependent Claim
24 words
The method of claim 6 wherein the separation of aromatics from non-aromatics and saturates using the anisotropic polyurea/urethane membrane is conducted under pervaporation conditions.
Claim 12
Dependent Claim
24 words
The method of claim 7 wherein the separation of aromatics from non-aromatics and saturates using the anisotropic polyurea/urethane membrane is conducted under pervaporation conditions.
Claim 13
Dependent Claim
24 words
The method of claim 4 wherein the separation of aromatics from non-aromatics and saturates using the anisotropic polyurea/urethane membrane is conducted under pervaporation conditions.
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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) | 1992-11-06 | 1993-05-08 | 1993-11-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-11-06 | 1997-05-08 | 1997-11-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-11-06 | 2001-05-08 | 2001-11-07 | $7700.00 | Window Closed / Lapsed |