Patent US4265675A successfully refreshed from Google Patents.
US4265675A
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Nontoxic cellulose solvent and process for forming and utilizing the same
Assignee: Purdue Research Foundation
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Filing: 1979-10-03
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Granted: 1981-05-05
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Expires: 1999-10-03
Abstract
Abstract A nontoxic cellulose solvent and process for forming and utilizing the same. The solvent includes a metal chelating agent, a metal compound, an oxygen scavenging stabilizing agent and a caustic swelling agent with the disclosed solvent being prepared in either aqueous or solid form. The solvent is caused to contact cellulosic materials in order to dissolve cellulose therefrom. The dissolved cellulose may be reprecipitated and may then be hydrolyzed by cellulose enzyme or acid to yield glucose with lignin being removed either before or after hydrolysis has occurred.
Inventors
- 👤 George T. Tsao
- 👤 Bruce E. Dale
- 👤 Michael R. Ladisch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 04:26
CPC Classifications
D; D21; D21C; D21C3/00; D21C3/006; C; C08; C08B; C08B1/00; C08B1/003; C13; C13K; C13K1/00; C13K1/02
Claims Analysis
Total Claims: 37
Claim 1
Independent Claim
23 words
A substantially nontoxic cellulose solvent, comprising: a metal chelating agent; a metal compound; a caustic swelling agent; and an oxygen scavenging stabilizing agent.
Claim 2
Dependent Claim
23 words
A substantially nontoxic cellulose solvent, comprising: a metal chelating agent; a metal compound; a caustic swelling agent; and an oxygen scavenging stabilizing agent.
Claim 3
Dependent Claim
12 words
The solvent of claim 1 wherein said solvent is in liquid form.
Claim 4
Dependent Claim
12 words
The solvent of claim 1 wherein said solvent is in solid form.
Claim 5
Dependent Claim
20 words
The solvent of claim 1 wherein said metal compound is ferric chloride and said caustic swelling agent is sodium hydroxide.
Claim 6
Dependent Claim
17 words
A substantially nontoxic cellulose solvent, comprising: sodium tartrate; ferric chloride; caustic; and an oxygen scavenging stabilizing agent.
Claim 7
Dependent Claim
17 words
A substantially nontoxic cellulose solvent, comprising: sodium tartrate; ferric chloride; caustic; and an oxygen scavenging stabilizing agent.
Claim 8
Dependent Claim
28 words
The solvent of claim 5 wherein said oxygen scavenging stabilizing agent is selected from the group consisting of sodium sulfite, glucose, galactose, other hexoses hydrazine and mixtures thereof.
Claim 9
Dependent Claim
47 words
The solvent of claim 2, which comprises, by weight, from about 3% to about 10% ferric chloride as said metal compound; from about 4% to about 15% sodium hydroxide as said caustic swelling agent; and from about 2.5% to about 11% of said oxygen scavenging stabilizing agent.
Claim 10
Dependent Claim
47 words
The solvent of claim 5, which comprises, by weight, from about 15% to about 20% sodium tartrate; from about 3% to about 10% ferric chloride; from about 4% to about 15% of said caustic; and from about 2.5% to about 11% of said oxygen scavenging stabilizing agent.
Claim 11
Dependent Claim
47 words
The solvent of claim 8, which comprises, by weight, from about 16% to about 18% sodium tartrate; from about 5.5% to about 7.5% ferric chloride; from about 6% to about 9% of said caustic; and from about 4.5% to about 8.5% of said oxygen scavenging stabilizing agent.
Claim 12
Dependent Claim
35 words
The solvent of claim 9, wherein said caustic comprises sodium hydroxide, and wherein said oxygen scavenging stabilizing agent is selected from the group consisting of sodium sulfite, glucose, galactose, other hexoses, hydrazine and mixtures thereof.
Claim 13
Dependent Claim
25 words
The solvent of claim 9, which comprises, by weight, about 17% sodium tartrate, about 6.6% ferric chloride, about 7.8% caustic, and about 6.2% sodium sulfite.
Claim 14
Dependent Claim
62 words
A substantially nontoxic solvent for dissolving and extracting cellulose from cellulosic material, which comprises: a caustic swelling agent for providing a high pH to loosen the cellulose structure of contacted cellulosic material; a metallic agent for giving access to said cellulose structure; a maintaining agent for keeping said metallic agent in solution; and an oxygen scavenging stabilizing agent for stabilizing the solvent.
Claim 15
Dependent Claim
62 words
A substantially nontoxic solvent for dissolving and extracting cellulose from cellulosic material, which comprises: a caustic swelling agent for providing a high pH to loosen the cellulose structure of contacted cellulosic material; a metallic agent for giving access to said cellulose structure; a maintaining agent for keeping said metallic agent in solution; and an oxygen scavenging stabilizing agent for stabilizing the solvent.
Claim 16
Dependent Claim
27 words
The solvent of claim 12, wherein said maintaining agent is selected from the group consisting of tartaric acid, citric acid, glyconic acid and alkali metal salts thereof.
Claim 17
Dependent Claim
39 words
The solvent of claim 13, wherein said maintaining agent is tartaric acid, wherein said metallic agent is FeCl 3 , wherein said loosening agent is NaOH, and wherein said oxygen scavenging stabilizing agent is Na 2 SO 3 .
Claim 18
Dependent Claim
45 words
The solvent of claim 14, which comprises about 10 g. of FeCl 3 .6H 2 O, about 17 g. of tartaric acid, about 22 g. of NaOH, about 13 g. of Na 2 SO 3 , and water to a total of about 200 g.
Claim 19
Independent Claim
34 words
A method for preparing a substantially nontoxic aqueous, cellulose solvent, comprising: adding tartaric acid to ferric chloride in water; adding sodium hydroxide; and adding an oxygen scavenging stabilizing agent to stabilize the aqueous solvent.
Claim 20
Independent Claim
34 words
A method for preparing a substantially nontoxic aqueous, cellulose solvent, comprising: adding tartaric acid to ferric chloride in water; adding sodium hydroxide; and adding an oxygen scavenging stabilizing agent to stabilize the aqueous solvent.
Claim 21
Dependent Claim
28 words
The method of claim 16, wherein said oxygen scavenging stabilizing agent is selected from the group consisting of sodium sulfite, glucose, galactose, other hexoses, hydrazine and mixtures thereof.
Claim 22
Dependent Claim
14 words
The method of claim 16, wherein said oxygen scavenging stabilizing agent is sodium sulfite.
Claim 23
Independent Claim
116 words
A method for preparing a solid cellulose solvent, said method comprising: adding to water a metallic agent which is capable of giving access to the cellulose structure in a cellulosic material and a maintaining agent for keeping said metallic agent in solution; adding a caustic swelling agent and an oxygen scavenging stabilizing agent to the solution formed in the previous step to provide a stabilized aqueous chelating metal caustic solvent; contacting said aqueous chelating metal caustic solvent with at least about 0.2 volumes of a water soluble organic solvent per volume of said aqueous solvent to precipitate a solid cellulose solvent; and separating said precipitated cellulose solvent from the mother liquor from which it was precipitated.
Claim 24
Independent Claim
116 words
A method for preparing a solid cellulose solvent, said method comprising: adding to water a metallic agent which is capable of giving access to the cellulose structure in a cellulosic material and a maintaining agent for keeping said metallic agent in solution; adding a caustic swelling agent and an oxygen scavenging stabilizing agent to the solution formed in the previous step to provide a stabilized aqueous chelating metal caustic solvent; contacting said aqueous chelating metal caustic solvent with at least about 0.2 volumes of a water soluble organic solvent per volume of said aqueous solvent to precipitate a solid cellulose solvent; and separating said precipitated cellulose solvent from the mother liquor from which it was precipitated.
Claim 25
Dependent Claim
68 words
The method of claim 19, wherein said metallic agent comprises ferric chloride; wherein said maintaining agent is selected from the group consisting of tartaric acid, citric acid, gluconic acid and alkali metal salts and mixtures thereof; wherein said caustic swelling agent comprises sodium hydroxide; and wherein said oxygen scavenging stabilizing agent is selected from the group consisting of sodium sulfite, glucose, galactose, other hexoses, hydrazine and mixtures thereof.
Claim 26
Dependent Claim
35 words
The method of claim 20, wherein said solid cellulose solvent is precipitated using from about 0.25 to about 5.0 volumes of methyl alcohol as said organic solvent for each volume of aqueous solvent being contacted.
Claim 27
Dependent Claim
54 words
A process for recovering cellulose from cellulosic materials, said process comprising: contacting a cellulosic material with an oxygen scavenger stabilized chelating metal caustic swelling solvent to dissolve the crystalline native cellulose contained in said cellulosic material and to transform the crystalline cellulose to an amorphous state; and precipitating said amorphous cellulose from said solvent.
Claim 28
Dependent Claim
54 words
A process for recovering cellulose from cellulosic materials, said process comprising: contacting a cellulosic material with an oxygen scavenger stabilized chelating metal caustic swelling solvent to dissolve the crystalline native cellulose contained in said cellulosic material and to transform the crystalline cellulose to an amorphous state; and precipitating said amorphous cellulose from said solvent.
Claim 29
Dependent Claim
40 words
The process of claim 22, wherein said chelating metal caustic swelling solvent includes sodium tartrate, ferric chloride, and caustic stabilized by an oxygen scavenger selected from the group consisting of sodium sulfite, glucose, galactose, other hexoses, hydrazine and mixtures thereof.
Claim 30
Dependent Claim
26 words
The process of claim 23, wherein said chelating metal caustic swelling solvent comprises an aqueous solvent at the time when the cellulosic material is contacted therewith.
Claim 31
Dependent Claim
37 words
The process of claim 23, wherein said chelating metal caustic swelling solvent is in solid form when the cellulosic material is contacted therewith, and wherein said solvent and the cellulosic material are intermixed during the contacting step.
Claim 32
Dependent Claim
31 words
The process of claim 22, wherein the cellulosic material is contacted with said chelating metal caustic swelling solvent in a weight ratio of from about 10:1 to about 1:10 cellulosic material:solvent.
Claim 33
Dependent Claim
18 words
The process of claim 22, wherein said precipitation of said amorphous cellulose is effected by addition of water.
Claim 34
Dependent Claim
22 words
The process of claim 27, wherein said chelating metal caustic swelling solvent is recovered from said water and is concentrated for recycle.
Claim 35
Dependent Claim
68 words
A process for recovering cellulose from a cellulosic material, said process comprising: providing a chelating metal caustic swelling solvent, said solvent comprising sodium tartrate, ferric chloride, caustic, and sodium sulfite; contacting a cellulosic material with said solvent in about a 10:1 to 1:10 weight ratio of cellulosic material to solvent; and adding water to precipitate cellulose from the solution formed by contacting the cellulosic material with said solvent.
Claim 36
Dependent Claim
68 words
A process for recovering cellulose from a cellulosic material, said process comprising: providing a chelating metal caustic swelling solvent, said solvent comprising sodium tartrate, ferric chloride, caustic, and sodium sulfite; contacting a cellulosic material with said solvent in about a 10:1 to 1:10 weight ratio of cellulosic material to solvent; and adding water to precipitate cellulose from the solution formed by contacting the cellulosic material with said solvent.
Claim 37
Dependent Claim
18 words
The process of claim 29, wherein said cellulose is hydrolyzed by acid and/or cellulase enzyme to yield glucose.
References Cited (Backward Citations)
US3251716A
Cited
US4024335A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-05-04 | 1984-11-03 | 1985-05-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-05-04 | 1988-11-03 | 1989-05-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-05-04 | 1992-11-03 | 1993-05-05 | $7700.00 | Window Closed / Lapsed |