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Patent US4058411A successfully refreshed from Google Patents.
US4058411A
Expired / Lapsed
US
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Decrystallization of cellulose
Assignee: BIOLOGICAL ENERGY Corp A CORP OF DE
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Filing: 1976-08-30
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Granted: 1977-11-15
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Expires: 1996-08-30
Abstract
Abstract A method for decrystallizing cellulose in natural cellulosic material which comprises admixing phosphoric acid with the cellulosic material to form a gel therewith, admixing tetrahydrofuran with the gel to extract the phosphoric acid forming a solution therewith and a precipitate of amorphous cellulose and recovering tetrahydrofuran and phosphoric acid from the solution for reuse in the process.
Inventors
- 👤 Winthrop D. Bellamy
- 👤 Fred F. Holub
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 05:16
CPC Classifications
C; C12; C12N; C12N1/00; C12N1/22; C08; C08B; C08B15/00; C13; C13K; C13K1/00; C13K1/02; Y; Y02; Y02P; Y02P20/00; Y02P20/50; Y02P20/582; Y10; Y10S; Y10S435/00; Y10S435/804
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
224 words
A process for decrystallizing cellulose in natural cellulosic material which comprises grinding said natural cellulosic material to a size of about 1 millimeter or less in diameter and length, admixing at ambient temperature phosphoric acid with the ground natural cellulosic material to form a gel-like mixture, said phosphoric acid ranging in concentration from 80 weight % to 85 weight % and being used in an amount sufficient to form said gel-like mixture, said phosphoric acid ranging in amount from 3 to 10 parts for one part of said cellulosic material transforming the crystalline regions of said cellulose to amorphous form, admixing at ambient temperature an aqueous solution of tetrahydrofuran with said gel-like mixture to extract said phosphoric acid therefrom forming a solution therewith and a precipitate of amorphous cellulose, said aqueous solution of tetrahydrofuran being comprised of 1 part of water for about 30 to 100 parts of tetrahydrofuran, said tetrahydrofuran being used in an amount sufficient to extract the phosphoric acid in at least a substantial amount, separating the resulting phosphoric acid-tetrahydrofuran solution from said precipitate, admixing the resulting separated precipitate with water at ambient temperature to form a water suspension thereof, and separating and recovering at least a substantial amount of said tetrahydrofuran and said phosphoric acid from the resulting phosphoric acid-tetrahydrofuran solution by distilling said tetrahydrofuran from said phosphoric acid-tetrahydrofuran solution.
Claim 2
Dependent Claim
224 words
A process for decrystallizing cellulose in natural cellulosic material which comprises grinding said natural cellulosic material to a size of about 1 millimeter or less in diameter and length, admixing at ambient temperature phosphoric acid with the ground natural cellulosic material to form a gel-like mixture, said phosphoric acid ranging in concentration from 80 weight % to 85 weight % and being used in an amount sufficient to form said gel-like mixture, said phosphoric acid ranging in amount from 3 to 10 parts for one part of said cellulosic material transforming the crystalline regions of said cellulose to amorphous form, admixing at ambient temperature an aqueous solution of tetrahydrofuran with said gel-like mixture to extract said phosphoric acid therefrom forming a solution therewith and a precipitate of amorphous cellulose, said aqueous solution of tetrahydrofuran being comprised of 1 part of water for about 30 to 100 parts of tetrahydrofuran, said tetrahydrofuran being used in an amount sufficient to extract the phosphoric acid in at least a substantial amount, separating the resulting phosphoric acid-tetrahydrofuran solution from said precipitate, admixing the resulting separated precipitate with water at ambient temperature to form a water suspension thereof, and separating and recovering at least a substantial amount of said tetrahydrofuran and said phosphoric acid from the resulting phosphoric acid-tetrahydrofuran solution by distilling said tetrahydrofuran from said phosphoric acid-tetrahydrofuran solution.
Claim 3
Dependent Claim
28 words
A process according to claim 1 wherein said aqueous solution of tetrahydrofuran contains at least 1 part of tetrahydrofuran for each part of phosphoric acid to be extracted.
Claim 4
Dependent Claim
55 words
A process according to claim 1 wherein about 0.01 part to 0.5 part of surfactant is admixed with 100 parts of said concentrated H 3 PO 4 acid, said surfactant being soluble and stable in said concentrated H 3 PO 4 acid at room temperature and having no significant deleterious effect on said cellulosic material.
References Cited (Backward Citations)
US1906429A
Cited
US3658588A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-11-14 | 1981-05-16 | 1981-11-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-11-14 | 1985-05-16 | 1985-11-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-11-14 | 1989-05-16 | 1989-11-15 | $7700.00 | Window Closed / Lapsed |