US4717394A
Expired / Lapsed
US
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Polyimide gas separation membranes
Assignee: LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
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Filing: 1986-10-27
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Granted: 1988-01-05
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Expires: 2006-10-27
Abstract
Abstract Semi-flexible aromatic polyimides, prepared by polycondensation of dianhydrides with diamines having alkyl substituents on all ortho positions to the amine functions, or with mixtures of diamines, some components having substituents on all positions ortho to the amine functions, are disclosed. Membranes formed from this class of polyimides have improved environmental stability and superior gas permeability. The range of gas permeation properties observed allows for the tailoring of membrane material for widely diverse gas separations. The high permeabilities of some gases from multicomponent mixtures is due to the optimization of the molecular free volume in the polymer.
Inventors
- 👤 Richard A. Hayes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 05:45
CPC Classifications
C; C08; C08G; C08G73/00; C08G73/06; C08G73/10; C08G73/1039; B; B01; B01D; B01D71/00; B01D71/06; B01D71/58; B01D71/62; B01D71/64; C08G73/1057; C08G73/1064; C08G73/1067; C08G73/1071; C08G73/1075
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
159 words
A process for separating gases comprising bringing two or more gases under pressuer into contact with a membrane formed of an aromatic polyimide comprising units of the formula ##STR11## where --Ar-- is ##STR12## or mixtures thereof, R is ##STR13## or mixtures thereof, --Ar'-- is ##STR14## or mixtures thereof, ##STR15## is ##STR16## or mixtures thereof, and --R"-- is ##STR17## where n=0 to 4, alkylene radicals of 1 to 3 carbon atoms or mixtures thereof, --X, --X 1 , --X 2 , and --X 3 are independently alkyl groups having 1 to 6 carbon atoms preferably methyl or ethyl, or aromatic groups of 6 to 13 carbon atoms, Z is --H, --X, --X 1 , --X 2 , or --X 3 W is 5% to 100% Q is 5% to 100% Y is 100% minus W V is 100% minus V Y plus V is at least 5%, whereby at least one of said gases is enriched upon permeating the membrane.
Claim 2
Dependent Claim
159 words
A process for separating gases comprising bringing two or more gases under pressuer into contact with a membrane formed of an aromatic polyimide comprising units of the formula ##STR11## where --Ar-- is ##STR12## or mixtures thereof, R is ##STR13## or mixtures thereof, --Ar'-- is ##STR14## or mixtures thereof, ##STR15## is ##STR16## or mixtures thereof, and --R"-- is ##STR17## where n=0 to 4, alkylene radicals of 1 to 3 carbon atoms or mixtures thereof, --X, --X 1 , --X 2 , and --X 3 are independently alkyl groups having 1 to 6 carbon atoms preferably methyl or ethyl, or aromatic groups of 6 to 13 carbon atoms, Z is --H, --X, --X 1 , --X 2 , or --X 3 W is 5% to 100% Q is 5% to 100% Y is 100% minus W V is 100% minus V Y plus V is at least 5%, whereby at least one of said gases is enriched upon permeating the membrane.
Claim 3
Dependent Claim
26 words
The The process of claim 1 wherein --X, --X 1 , --X 2 , or --X 3 are --CH 3 or --C 2 H 5 .
Claim 4
Dependent Claim
12 words
The process of claim 2 wherein R is ##STR18## or mixtures thereof.
Claim 5
Dependent Claim
132 words
A gas separation membrane formed of an aromatic polyimide comprising units of the formula ##STR19## where --Ar-- is ##STR20## or mixtures thereof, --R-- is ##STR21## or mixtures thereof, --Ar'-- is ##STR22## or mixtures thereof, ##STR23## is ##STR24## or mixtures thereof, and --R"-- is ##STR25## where n=0 to 4, alkylene radicals of 1 to 3 carbon atoms or mixtures thereof, --X, --X 1 , --X 2 , and --X 3 are independently alkyl groups having 1 to 6 carbon atoms preferably methyl or ethyl, or aromatic groups of 6 to 13 carbon atoms, Z is --H, --X, --X 1 , --X 2 , or X 3 W is 5% to 100% Q is 5% to 100% Y is 100% minus W V is 100% minus V Y plus V is at least 5%.
Claim 6
Dependent Claim
132 words
A gas separation membrane formed of an aromatic polyimide comprising units of the formula ##STR19## where --Ar-- is ##STR20## or mixtures thereof, --R-- is ##STR21## or mixtures thereof, --Ar'-- is ##STR22## or mixtures thereof, ##STR23## is ##STR24## or mixtures thereof, and --R"-- is ##STR25## where n=0 to 4, alkylene radicals of 1 to 3 carbon atoms or mixtures thereof, --X, --X 1 , --X 2 , and --X 3 are independently alkyl groups having 1 to 6 carbon atoms preferably methyl or ethyl, or aromatic groups of 6 to 13 carbon atoms, Z is --H, --X, --X 1 , --X 2 , or X 3 W is 5% to 100% Q is 5% to 100% Y is 100% minus W V is 100% minus V Y plus V is at least 5%.
Claim 7
Dependent Claim
13 words
The membrane of claim 4 wherein Y plus V is 10 to 50%.
Claim 8
Dependent Claim
25 words
The membrane of claim 5 wherein --X, --X 1 , --X 2 , or --X 3 are --CH 3 or --C 2 H 5 .
Claim 9
Dependent Claim
9 words
The membrane of claim 6 wherein Y is --0.
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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) | 1991-01-04 | 1991-07-06 | 1992-01-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-01-04 | 1995-07-06 | 1996-01-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-01-04 | 1999-07-06 | 2000-01-05 | $7700.00 | Window Closed / Lapsed |