US5006255A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Selective permeable membrane for separation of liquid solution
Assignee: Lignyte Co Ltd
•
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 05:53
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.
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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) | 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 |