Patent US5006255A successfully refreshed from Google Patents.
US5006255A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Selective permeable membrane for separation of liquid solution
Assignee: Lignyte Co Ltd
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Filing: 1988-10-11
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Granted: 1991-04-09
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Expires: 2008-10-11
Abstract
Abstract A novel selective permeable membrane is made by cross-linking of chitosan by aldehyde, preferably by dialdehyde. The dialdehyde cross-linked membrane has a remarkably high separation efficiency for water-alcohol solution due to hydrophilic property of chitosan and its very dense structure obtained by the cross-linking of chitosan with dialdehyde.
Inventors
- 👤 Tadashi Uragami
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 06:10
CPC Classifications
B; B01; B01D; B01D1/00; B01D1/0011; B01D1/0041; B01D1/0052; B01D71/00; B01D71/06; B01D71/08; C; C08; C08B; C08B37/00; C08B37/0006; C08B37/0024; C08B37/0027; C08B37/003
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
78 words
A process of selectively separating water from a liquid solution containing water and an organic solvent, which comprises contacting the solution with a permeable membrane made of chitosan cross-linked with a dialdehyde and having the following general formula: ##STR3## wherein n represents an integer of 200 to 20,000, and R represents a group of formula: --(CH 2 ) m --wherein m represents an integer of 1 or more, or ##STR4## whereby water selectively vaporizes and permeates the membrane.
Claim 2
Dependent Claim
78 words
A process of selectively separating water from a liquid solution containing water and an organic solvent, which comprises contacting the solution with a permeable membrane made of chitosan cross-linked with a dialdehyde and having the following general formula: ##STR3## wherein n represents an integer of 200 to 20,000, and R represents a group of formula: --(CH 2 ) m --wherein m represents an integer of 1 or more, or ##STR4## whereby water selectively vaporizes and permeates the membrane.
Claim 3
Dependent Claim
24 words
A process according to claim 1, wherein the chitosan has a molecular weight of between 50,000 to 5,000,000 and is 60 to 100% deacetylated.
Claim 4
Dependent Claim
23 words
A process according to claim 1, wherein the dialdehyde is a glyoxal, malondialdehyde, succindialdehyde, glutardialdehyde, adipicdialdehyde, maleindialdehyde, phthaldialdehyde, isophthaldialdehyde, telephthaldialdehyde or dialdehyde starch.
Claim 5
Dependent Claim
73 words
A process of selectively separating water from an aqueous solution containing ethyl alcohol, which comprises contacting the solution with a membrane made of chitosan cross-linked with a dialdehyde and having the following general formula: ##STR5## wherein n represents an integer of 200 to 20,000, and R represents a group of formula: --(CH 2 ) m --wherein m represents an integer of 1 or more, or whereby water selectively vaporizes and permeates the membrane.
Claim 6
Dependent Claim
73 words
A process of selectively separating water from an aqueous solution containing ethyl alcohol, which comprises contacting the solution with a membrane made of chitosan cross-linked with a dialdehyde and having the following general formula: ##STR5## wherein n represents an integer of 200 to 20,000, and R represents a group of formula: --(CH 2 ) m --wherein m represents an integer of 1 or more, or whereby water selectively vaporizes and permeates the membrane.
Claim 7
Dependent Claim
24 words
A process according to claim 4, wherein the chitosan has a molecular weight of between 50,000 to 5,000,000 and is 60 to 100% deacetylated.
Claim 8
Dependent Claim
23 words
A process according to claim 4, wherein the dialdehyde is a glyoxal, malondialdehyde, succindialdehyde, glutardialdehyde, adipicdialdehyde, maleindialdehyde, phthaldialdehyde, isophthaldialdehyde, telephthaldialdehyde or dialdehyde starch.
References Cited (Backward Citations)
US2788316A
Cited
US2953502A
Cited
US3415719A
Cited
US3455792A
Cited
US3562116A
Cited
US4111810A
Cited
US3962158A
Cited
US4125708A
Cited
US4406096A
Cited
US4808313A
Cited
US4708947A
Cited
US4814132A
Cited
US4659590A
Cited
US4719016A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-04-08 | 1994-10-08 | 1995-04-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-04-08 | 1998-10-08 | 1999-04-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-04-08 | 2002-10-08 | 2003-04-09 | $7700.00 | Window Closed / Lapsed |