Patent US4041233A successfully refreshed from Google Patents.
US4041233A
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Aldehyde-containing urea-absorbing polysaccharides
Assignee: National Aeronautics and Space Administration
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Filing: 1976-03-15
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Granted: 1977-08-09
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Expires: 1996-03-15
Abstract
Abstract A novel aldehyde-containing polymer (ACP) is prepared by reaction of a polysaccharide with periodate to introduce aldehyde groups onto the C 2 - C 3 carbon atoms and by introduction of ether and ester groups onto the pendant primary hydroxyl to modify solubility characteristics. The ACP is utilized to absorb nitrogen bases such as urea in vitro or in vivo.
Inventors
- 👤 with respect to an invention of Fletcher James C. Administrator of the National Aeronautics and Space Administration
- 👤 William A. Mueller
- 👤 George C. Hsu
- 👤 Harold E. Marsh, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 03:04
CPC Classifications
C; C08; C08B; C08B31/00; C08B31/18; C08B31/185; C08B15/00
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
43 words
A modified polysaccharide containing 10% to 35% by weight of C 2 - C 3 aldehyde groups and in which 0.05 to 0.5 of the amylose units are of the formula: ##STR5## where R is the residue of an ether or ester moiety.
Claim 2
Dependent Claim
43 words
A modified polysaccharide containing 10% to 35% by weight of C 2 - C 3 aldehyde groups and in which 0.05 to 0.5 of the amylose units are of the formula: ##STR5## where R is the residue of an ether or ester moiety.
Claim 3
Dependent Claim
42 words
A polysaccharide according to claim 1 in which R is an alkyl of 1 to 6 carbon atoms, phenyl, alkylated phenyl, carboxyalkyl of 1 to 6 carbon atoms or the ester residue of an alkanonic acid of 1 to 6 carbon atoms.
Claim 4
Dependent Claim
11 words
A polysaccharide according to claim 2 in which R is carboxymethyl.
Claim 5
Dependent Claim
11 words
A polysaccharide according to claim 2 in which R is methyl.
Claim 6
Dependent Claim
14 words
A polysaccharide according to claim 1 having a molecular weight from 30,000 to 14,000,000.
Claim 7
Dependent Claim
11 words
A polysaccharide according to claim 5 selected from starch or cellulose.
Claim 8
Independent Claim
102 words
A method of producing a modified polysaccharide comprising the steps in sequence: modifying 0.05 to 0.5 of the primary hydroxyl groups of the amylose units to introduce an ether or ester group thereon; and oxidizing the C 2 - C 3 hydroxyl groups of the amylose units to dialdehyde groups at pH 4-5 with 0.5 to 1.5 moles of an alkali metal periodate per mole of polysaccharide to introduce from 10% to 35% be weight of C 2 - C 3 aldehyde groups to form amylose units of the formula: ##STR6## where R is the residue of an ether or ester moiety.
Claim 9
Independent Claim
102 words
A method of producing a modified polysaccharide comprising the steps in sequence: modifying 0.05 to 0.5 of the primary hydroxyl groups of the amylose units to introduce an ether or ester group thereon; and oxidizing the C 2 - C 3 hydroxyl groups of the amylose units to dialdehyde groups at pH 4-5 with 0.5 to 1.5 moles of an alkali metal periodate per mole of polysaccharide to introduce from 10% to 35% be weight of C 2 - C 3 aldehyde groups to form amylose units of the formula: ##STR6## where R is the residue of an ether or ester moiety.
References Cited (Backward Citations)
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US2648629A
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US3086969A
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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) | 1980-08-08 | 1981-02-07 | 1981-08-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-08-08 | 1985-02-07 | 1985-08-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-08-08 | 1989-02-07 | 1989-08-09 | $7700.00 | Window Closed / Lapsed |