Patent US4420612A successfully refreshed from Google Patents.
US4420612A
Expired / Lapsed
US
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Catalyst membrane
Assignee: National Institute of Advanced Industrial Science and Technology
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Filing: 1983-02-28
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Granted: 1983-12-13
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Expires: 2003-02-28
Abstract
Abstract A catalyst membrane including a porous polytetrafluoroethylene membrane having grafted thereon polystyrenesulfonic acid. The catalyst membrane is useful for hydrolyzing water soluble organic substances such as polysaccharides.
Inventors
- 👤 Seiichi Aiba
- 👤 Kazuhisa Hiratani
- 👤 Tsutomu Nakagawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 21:35
CPC Classifications
C; C13; C13K; C13K1/00; C13K1/06; B; B01; B01D; B01D61/00; B01D67/00; B01D67/0081; B01D67/0093; B01D67/00931; B01D71/00; B01D71/06; B01D71/30; B01D71/32; B01J; B01J14/00; B01J14/005; B01J31/00; B01J31/02; B01J31/06; B01J31/08; B01J31/10; B01J35/00; B01J35/30; B01J35/391; B01J35/395; B01D2311/00; B01D2311/26; B01D2311/2696; B01D2323/00; B01D2323/38; B01D2323/385; B01J35/34; B01J35/36
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
56 words
A method of hydrolyzing an acid-catalyzable, water soluble organic substance, comprising contacting a solution containing said substance with a catalyst membrane which comprises a porous polytetrafluoroethylene membrane having grafted thereon polystyrenesulfonic acid, wherein said porous polytetrafluoroethylene membrane has a thickness of 30 to 200 u and an average pore size diameter of 0.1 to 1.2 u.
Claim 2
Independent Claim
56 words
A method of hydrolyzing an acid-catalyzable, water soluble organic substance, comprising contacting a solution containing said substance with a catalyst membrane which comprises a porous polytetrafluoroethylene membrane having grafted thereon polystyrenesulfonic acid, wherein said porous polytetrafluoroethylene membrane has a thickness of 30 to 200 u and an average pore size diameter of 0.1 to 1.2 u.
Claim 3
Dependent Claim
43 words
A method as set forth in claim 1, wherein said solution is contacted with one side of said catalyst membrane, with the other side thereof being contacted with water so that the hydrolysis product may diffuse through said catalyst membrane into said water.
Claim 4
Dependent Claim
57 words
A method as set forth in claim 1, wherein said catalyst membrane is prepared by a process comprising the steps of: providing a porous polytetrafluoroethylene membrane; grafting polystyrene on said polytetrafluoroethylene membrane; and reacting said membrane having polystyrene grafted thereon with a sulfonating agent to incorporate sulfonic acid groups into the benzene nuclei of the grafted polystyrene.
Claim 5
Dependent Claim
41 words
A method as set forth in claim 3, wherein said porous polytetrafluoroethylene membrane has a perviousness such that air can pass therethrough at a flow rate of about 0.85-16 liters per min. per square centimeter of said membrane at 25° C.
Claim 6
Dependent Claim
22 words
A method as set forth in claim 1, wherein said organic substance is a carboxylic acid ester, an amide or a polysaccharide.
Claim 7
Dependent Claim
20 words
A method as set forth in claim 5, wherein said organic substance has a molecular weight of 1000 to 50000.
Claim 8
Dependent Claim
24 words
A method as set forth in claim 6, wherein said organic substance is a fatty acid ester, a fatty amide, starch, dextrin or amylose.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-12-12 | 1987-06-13 | 1987-12-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-12-12 | 1991-06-13 | 1991-12-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-12-12 | 1995-06-13 | 1995-12-13 | $7700.00 | Window Closed / Lapsed |