US4428776A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cellulosic semipermeable membranes containing silicon compounds
Assignee: Standard Oil Co
•
Filing: 1982-06-23
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Granted: 1984-01-31
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Expires: 2002-06-23
Abstract
Abstract Semipermeable membranes prepared from at least one cellulosic polymer, such as cellulose triacetate, and containing at least one silicon compound, such as tetraethoxy silane, are useful for the separation of various gaseous mixtures into their constituent parts, such as separating natural gas into enriched fractions of carbon dioxide and methane.
Inventors
- 👤 George S. Li
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 00:45
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/22; B01D53/228; B01D71/00; B01D71/06; B01D71/08; B01D71/12; B01D71/14; B01D71/22
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
149 words
A semipermeable membrane useful for separating a gaseous mixture of carbon dioxide and methane into enriched fractions of each, the membrane prepared from at least one cellulosic polymer and at least one silicon compound of the formulae ##STR2## where each R is independently a hydrogen radical, a halide radical, or an aliphatic, cycloaliphatic or aromatic radical or an inertly-substituted derivative of any one of them, with the provisoes that where R is directly bonded to oxygen, R is not a halide radical and in formula I when n is zero, at least one R is a radical other than hydrogen; n is an integer of 0-4; p is an integer of at least 1; q is an integer of 1-3; and the silicon compound comprises between about 5 and about 50 weight percent of the membrane, based on the combined weight of the silicon compound and the cellulosic polymer.
Claim 2
Dependent Claim
149 words
A semipermeable membrane useful for separating a gaseous mixture of carbon dioxide and methane into enriched fractions of each, the membrane prepared from at least one cellulosic polymer and at least one silicon compound of the formulae ##STR2## where each R is independently a hydrogen radical, a halide radical, or an aliphatic, cycloaliphatic or aromatic radical or an inertly-substituted derivative of any one of them, with the provisoes that where R is directly bonded to oxygen, R is not a halide radical and in formula I when n is zero, at least one R is a radical other than hydrogen; n is an integer of 0-4; p is an integer of at least 1; q is an integer of 1-3; and the silicon compound comprises between about 5 and about 50 weight percent of the membrane, based on the combined weight of the silicon compound and the cellulosic polymer.
Claim 3
Dependent Claim
17 words
The membrane of claim 1 where the cellulosic polymer is an ester or ether derivative of cellulose.
Claim 4
Dependent Claim
23 words
The membrane of claim 2 where the cellulosic polymer is at least one of methyl cellulose, ethyl cellulose, cellulose diacetate and cellulose triacetate.
Claim 5
Dependent Claim
19 words
The membrane of claim 3 where the silicon compound is at least one of formulae I, II and III.
Claim 6
Dependent Claim
39 words
The membrane of claim 4 where each R is independently a hydrogen radical, a halide radical, a C 1 -C 8 alkyl, C 5 -C 7 cycloalkyl or phenyl radical or an inertly-substituted derivative of any one of them.
Claim 7
Dependent Claim
27 words
A membrane of claim 5 where the silicon compound is at least one of a disiloxane, a tetraalkoxy silane, a dialkyldialkoxy silane, a polysiloxane and a trisiloxane.
Claim 8
Dependent Claim
34 words
The membrane of claim 6 where the silicon compound comprises between about 10 and about 30 weight percent of the membrane, based upon the combined weight of the silicon compound and the cellulosic polymer.
Claim 9
Dependent Claim
16 words
The membrane of claim 7 where the membrane has a thickness less than about 25 mils.
Claim 10
Dependent Claim
12 words
The membrane of claim 7 where the membrane is a hollow fiber.
Claim 11
Dependent Claim
15 words
The membrane of claim 7 where the membrane is a coating on an underlying substrate.
References Cited (Backward Citations)
US3440264A
Cited
US3657113A
Cited
US3754375A
Cited
US3781378A
Cited
USRE30351E
Cited
US4171987A
Cited
US4106948A
Cited
US4230463A
Cited
US4214020A
Cited
US4305823A
Cited
US4180552A
Cited
US4305824A
Cited
US4374933A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-01-30 | 1987-08-01 | 1988-01-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-01-30 | 1991-08-01 | 1992-01-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-01-30 | 1995-08-01 | 1996-01-31 | $7700.00 | Window Closed / Lapsed |