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US4058411A Expired / Lapsed US ⏱️ 0.0 years remaining

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
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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

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