Patent US4833237A successfully refreshed from Google Patents.
US4833237A
Expired / Lapsed
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Process for producing granular porous chitosan
Assignee: Fujibo Holdings Inc
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Filing: 1987-02-05
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Granted: 1989-05-23
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Expires: 2007-02-05
Abstract
Abstract A process for producing granular porous chitosan of extremely uniform particle size and having uniform fine pores on the spherical surface and cut cross sectional face. The process comprises dissolving a low molecular weight chitosan into an aqueous acidic solution, pouring the solution into a basic solution and thereby coagulating the product to precipitate porous chitosan.
Inventors
- 👤 Yoshihide Kawamura
- 👤 Hiroaki Tanibe
- 👤 Itsuo Kurahashi
- 👤 Hiroshi Seo
- 👤 Saburo Nakajima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 12:27
CPC Classifications
C; C08; C08L; C08L5/00; C08L5/08; C08B; C08B37/00; C08B37/0006; C08B37/0024; C08B37/0027; C08B37/003
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
76 words
A process for producing granular porous chitosan, which comprises dissolving a chitosan having a mean molecular weight of 10,000 to 230,000 in an amount of from 2 to 20% by weight into an aqueous acidic solution, thereby forming an intermediate solution consisting essentially of said chitosan and said aqueous acidic solution; and pouring said intermediate solution into a basic solution to precipitate porous chitosan having a specific surface area of 15 to 98 m 2 /g.
Claim 2
Dependent Claim
76 words
A process for producing granular porous chitosan, which comprises dissolving a chitosan having a mean molecular weight of 10,000 to 230,000 in an amount of from 2 to 20% by weight into an aqueous acidic solution, thereby forming an intermediate solution consisting essentially of said chitosan and said aqueous acidic solution; and pouring said intermediate solution into a basic solution to precipitate porous chitosan having a specific surface area of 15 to 98 m 2 /g.
Claim 3
Dependent Claim
27 words
The process according to claim 1, wherein the basic solution comprises a base and water; a base, water and an alcohol; or a base and an alcohol.
Claim 4
Dependent Claim
28 words
The process according to claim 2, wherein the basic solution is selected from the group consisting of NaOH-water system, NaOH-alcohol-water system, ethylenediamine-alcohol system, ammonia-water system and ammonia-alcohol-water system.
Claim 5
Dependent Claim
51 words
The process according to claim 1, further comprising reacting said porous chitosan with an organic diisocyanate in an amount of 0.2 to 2.0 moles per mole of glucosamine residue of said porous chitosan in a polar solvent to provide a product having a bed volume recovery rate of 56 to 98%.
Claim 6
Dependent Claim
36 words
The process according to claim 4, wherein the organic diisocyanate is selected from the group consisting of 4,4'-diphenylmethane diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate, naphthalene diisocyanate, 1,4-cyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, xylylene diisocyanate, isophorone diisocyanate and hexamethylene diisocyanate.
Claim 7
Dependent Claim
18 words
The process according to claim 5, wherein the organic diisocyanate is hexamethylene diisocyanate, xylylene diisocyante or 4,4'-diphenylmethane diisocyanate.
Claim 8
Dependent Claim
120 words
A granular porous chitosan prepared by a process which comprises: dissolving a chitosan having a mean molecular weight of 10,000 to 230,000 in an amount of from 2 to 20% by weight into an aqueous acidic solution, thereby forming an intermediate solution consisting essentially of said chitosan and said aqueous acidic solution; pouring said intermediate solution into a basic solution to precipitate porous chitosan having a specific surface area of 15 to 98 m 2 /g; and reacting said porous chitosan with an organic diisocyanate in an amount of 0.2 to 2.0 moles per mole of glucosamine residue of said porous chitosan in a polar solvent to provide a product having a bed volume recovery rate of 56 to 98%
Claim 9
Dependent Claim
120 words
A granular porous chitosan prepared by a process which comprises: dissolving a chitosan having a mean molecular weight of 10,000 to 230,000 in an amount of from 2 to 20% by weight into an aqueous acidic solution, thereby forming an intermediate solution consisting essentially of said chitosan and said aqueous acidic solution; pouring said intermediate solution into a basic solution to precipitate porous chitosan having a specific surface area of 15 to 98 m 2 /g; and reacting said porous chitosan with an organic diisocyanate in an amount of 0.2 to 2.0 moles per mole of glucosamine residue of said porous chitosan in a polar solvent to provide a product having a bed volume recovery rate of 56 to 98%
Claim 10
Dependent Claim
29 words
A granular porous chitosan according to claim 7 wherein the basic solution comprises a base and water; a base, water and an alcohol; or a base and an alcohol.
Claim 11
Dependent Claim
30 words
A granular porous chitosan according to claim 8, wherein the basic solution is selected from the group consisting of NaOH-water system, NaOH-alcohol-water system, ethylenediamine-alcohol system, ammonia-water system and ammonia-alcohol-water system.
Claim 12
Dependent Claim
38 words
A granular porous chitosan according to claim 4, wherein the organic diisocyanate is selected from the group consisting of 4,4'-diphenylmethane diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate, naphthalene diisocyanate, 1,4-cyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, xylylene diisocyanate, isophorone diisocyanate and hexamethylene diisocyanate.
Claim 13
Dependent Claim
20 words
A granular porous chitosan according to claim 10, wherein the organic diisocyanate is hexamethylene diisocyanate, xylylene diisocyanate or 4,4'-diphenylmethane diisocyanate.
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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) | 1992-05-22 | 1992-11-21 | 1993-05-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-05-22 | 1996-11-21 | 1997-05-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-05-22 | 2000-11-21 | 2001-05-23 | $7700.00 | Window Closed / Lapsed |