US4705540A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polyimide gas separation membranes
Assignee: EIDP Inc
•
Filing: 1986-04-17
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Granted: 1987-11-10
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Expires: 2006-04-17
Abstract
Abstract A highly permeable aromatic polyimide gas separation membrane and the process of using it are disclosed. The aromatic polyimide has the formula ##STR1## wherein --Ar-- is ##STR2## or mixtures thereof, --X, --X 1 , --X 2 and --X 3 independently are alkyl groups having 1 to 6 carbon atoms or aromatic groups having 6 to 13 carbon atoms, and --Z is --H, --X, --X 1 , --X 2 , or --X 3 ; and R is ##STR3## or mixtures thereof.
Inventors
- 👤 Richard A. Hayes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 08:34
CPC Classifications
B; B01; B01D; B01D71/00; B01D71/06; B01D71/58; B01D71/62; B01D71/64; C; C08; C08G; C08G73/00; C08G73/06; C08G73/10; C08G73/1039; C08G73/1067
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
72 words
A gas separation membrane formed of an aromatic polyimide of the formula ##STR7## where --Ar-- is ##STR8## or mixture thereof, and R is ##STR9## or mixtures thereof and --X, --X 1 , --X 2 , and --X 3 are independently alkyl groups having 1 to 6 carbon atoms or aromatic groups having 6 to 13 carbon atoms, and --Z is --H, --X, --X 1 , --X 2 , or --X 3 .
Claim 2
Dependent Claim
72 words
A gas separation membrane formed of an aromatic polyimide of the formula ##STR7## where --Ar-- is ##STR8## or mixture thereof, and R is ##STR9## or mixtures thereof and --X, --X 1 , --X 2 , and --X 3 are independently alkyl groups having 1 to 6 carbon atoms or aromatic groups having 6 to 13 carbon atoms, and --Z is --H, --X, --X 1 , --X 2 , or --X 3 .
Claim 3
Dependent Claim
25 words
The membrane of claim 1 wherein --X, --X 1 , --X 2 , or --X 3 are --CH 3 or --C 2 H 5 .
Claim 4
Dependent Claim
9 words
The membrane of claim 2 wherein R is ##STR10##
Claim 5
Dependent Claim
118 words
A process of separating two or more gases comprising of steps of bringing a mixture of two or more gases into contact with one side of a permselective membrane which is formed from an aromatic polyimide of the formula ##STR11## where --Ar-- is ##STR12## or or mixtures thereof, and R' is ##STR13## or mixtures thereof and --X, --X 1 , --X 2 , and --X 3 are independently alkyl groups of 1 to 6 carbon atoms, or aromatic group having 6 to 13 carbon atoms and --Z is --H, --X, --X 1 , --X 2 , or --X 3 whereby one of said gases permeates said membrane at a different productivity rate than at least one other gas.
Claim 6
Dependent Claim
118 words
A process of separating two or more gases comprising of steps of bringing a mixture of two or more gases into contact with one side of a permselective membrane which is formed from an aromatic polyimide of the formula ##STR11## where --Ar-- is ##STR12## or or mixtures thereof, and R' is ##STR13## or mixtures thereof and --X, --X 1 , --X 2 , and --X 3 are independently alkyl groups of 1 to 6 carbon atoms, or aromatic group having 6 to 13 carbon atoms and --Z is --H, --X, --X 1 , --X 2 , or --X 3 whereby one of said gases permeates said membrane at a different productivity rate than at least one other gas.
Claim 7
Dependent Claim
24 words
The process of claim 4 wherein --X, --X 1 , --X 2 , --X 3 are --CH 3 or --C 2 H 5 .
Claim 8
Dependent Claim
9 words
The process of claim 5 wherein R is ##STR14##
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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) | 1990-11-09 | 1991-05-11 | 1991-11-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-11-09 | 1995-05-11 | 1995-11-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-11-09 | 1999-05-11 | 1999-11-10 | $7700.00 | Window Closed / Lapsed |