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Patent US4871378A successfully refreshed from Google Patents.
US4871378A
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US
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Ultrathin ethylcellulose/poly(4-methylpentene-1) permselective membranes
Assignee: Membrane Technology and Research Inc
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Filing: 1987-12-11
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Granted: 1989-10-03
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Expires: 2007-12-11
Abstract
Abstract An ultrathin, permselective membrane for use in gas or vapor separations. The membrane comprises a permselective layer of ethylcellulose in combination with one or more permselective layers of poly(4-methylpentene-1). The permselective membrane is preferably coated onto a microporous substrate, such as an asymmetric Loeb-Sourirajan type membrane. The resulting membrane has high gas fluxes and selectivities, and can be used, for example, to separate oxygen and nitrogen; hydrogen sulfide from nitrogen, methane or carbon dioxide; hydrogen from nitrogen; sulfur dioxide or ammonia from nitrogen; or water vapor from air. A method of preparing such a membrane is also provided, as is a gas separation process using the membrane.
Inventors
- 👤 Ingo Pinnau
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 15:45
CPC Classifications
B; B01; B01D; B01D71/00; B01D71/06; B01D71/08; B01D71/12; B01D71/22; B01D69/00; B01D69/10; B01D69/106; B01D69/12; B01D69/1216
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
91 words
A membrane useful for gas separation, comprising: an ultrathin, permselective ethylcellulose layer having the general formula ##STR5## wherein the ethoxyl content is in the range 35% to 50%; and an ultrathin, permselective poly(4-methylpentene-1) layer having the formula ##STR6## said poly(4-methylpentene-1) layer forming a coating on one surface of said ethylcellulose layer, said membrane having an O 2 /N 2 selectivity which is greater than the intrinsic O 2 /N 2 selectivity of said ethylcellulose and which is greater than 90% of the intrinsic O 2 /N 2 selectivity of said poly(4-methylpentene-1).
Claim 2
Dependent Claim
91 words
A membrane useful for gas separation, comprising: an ultrathin, permselective ethylcellulose layer having the general formula ##STR5## wherein the ethoxyl content is in the range 35% to 50%; and an ultrathin, permselective poly(4-methylpentene-1) layer having the formula ##STR6## said poly(4-methylpentene-1) layer forming a coating on one surface of said ethylcellulose layer, said membrane having an O 2 /N 2 selectivity which is greater than the intrinsic O 2 /N 2 selectivity of said ethylcellulose and which is greater than 90% of the intrinsic O 2 /N 2 selectivity of said poly(4-methylpentene-1).
Claim 3
Dependent Claim
24 words
The membrane of claim 1, further comprising a microporous support membrane, said ethylcellulose layer forming a coating on one side of said support membrane.
Claim 4
Dependent Claim
15 words
The membrane of claim 1, wherein said ethylcellulose layer is less than 2 microns thick.
Claim 5
Dependent Claim
15 words
The membrane of claim 1, wherein said poly(4-methylpentene-1) layer is less than 2 microns thick.
Claim 6
Dependent Claim
72 words
A process for separating a gas A from a gas B in a first gas mixture containing A and B, comprising the steps of: contacting the feed side of the membrane of claim 1 with said gas mixture; and withdrawing from the permeate side of said membrane a second gas mixture wherein the proportion of gas A is enriched, and the proportion of gas B depleted, compared to said first gas mixture.
Claim 7
Dependent Claim
132 words
A process for producing a membrane useful for gas separation comprising the steps of: preparing an ethylcellulose solution from ethylcellulose having the general formula ##STR7## wherein the ethoxyl content is in the range 35% to 50%; coating said ethylcellulose solution onto a support; drying said coated support, to produce a first ultrathin, permselective layer of ethylcellulose; preparing a poly(4-methylpentene-1) solution from poly(4methylpentene-1) having the formula ##STR8## coating said poly(4-methylpentene-1) solution onto said coated support; and drying said coated support, to produce a second ultrathin, permselective layer of poly(4-methylpentene-1, whereby a composite membrane, having an O 2 /N 2 selectivity which is greater than the intrinsic O 2 /N 2 selectivity of said ethylcellulose and which is greater than 90% of the intrinsic O 2 /N 2 selectivity of said poly(4-methylpentene-1), is formed.
Claim 8
Dependent Claim
132 words
A process for producing a membrane useful for gas separation comprising the steps of: preparing an ethylcellulose solution from ethylcellulose having the general formula ##STR7## wherein the ethoxyl content is in the range 35% to 50%; coating said ethylcellulose solution onto a support; drying said coated support, to produce a first ultrathin, permselective layer of ethylcellulose; preparing a poly(4-methylpentene-1) solution from poly(4methylpentene-1) having the formula ##STR8## coating said poly(4-methylpentene-1) solution onto said coated support; and drying said coated support, to produce a second ultrathin, permselective layer of poly(4-methylpentene-1, whereby a composite membrane, having an O 2 /N 2 selectivity which is greater than the intrinsic O 2 /N 2 selectivity of said ethylcellulose and which is greater than 90% of the intrinsic O 2 /N 2 selectivity of said poly(4-methylpentene-1), is formed.
Claim 9
Dependent Claim
18 words
The process as in claim 6, wherein said ethylcellulose solution contains a maximum ethylcellulose concentration of 5 wt%.
Claim 10
Dependent Claim
18 words
The process as in claim 6, wherein said ethylcellulose solution contains a maximum ethylcellulose concentration of 2 wt%.
Claim 11
Dependent Claim
34 words
The process as in claim 6, wherein said ethylcellulose solution comprises ethylcellulose having the general formula ##STR9## wherein the ethoxyl content is in the range 35% to 50%, dissolved in a monohydric aliphatic alcohol.
Claim 12
Dependent Claim
13 words
The process as in claim 9, wherein said monohydric aliphatic alcohol is 2-propanol.
Claim 13
Dependent Claim
18 words
The process as in claim 6, wherein said poly(4-methylpentene-1) solution contains a maximum poly(4-methylpentene-1) concentration of 5 wt%.
Claim 14
Dependent Claim
18 words
The process as in claim 6, wherein said poly(4-methylpentene-1) solution contains a maximum poly(4-methylpentene-1) concentration of 2 wt%.
Claim 15
Dependent Claim
15 words
The process as in claim 6, wherein said poly(4-methylpentene-1) solution comprises poly(4-methylpentene-1) dissolved in cyclohexane.
References Cited (Backward Citations)
US3767737A
Cited
US3874986A
Cited
US3980456A
Cited
US4132824A
Cited
US4230463A
Cited
US4277344A
Cited
US4243701A
Cited
US4559139A
Cited
US4406673A
Cited
US4533369A
Cited
JPS59137303A
Cited
US4664669A
Cited
US4664681A
Cited
US4581043A
Cited
EP0152011A2
Cited
JPS61125424A
Cited
JPS61278330A
Cited
US4681605A
Cited
US4713292A
Cited
JPS6227025A
Cited
JPS62136224A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-10-02 | 1993-04-03 | 1993-10-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-10-02 | 1997-04-03 | 1997-10-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-10-02 | 2001-04-03 | 2001-10-03 | $7700.00 | Window Closed / Lapsed |