CA1118381A - Nontoxic cellulose solvent and process for forming and utilizing the same - Google Patents
Nontoxic cellulose solvent and process for forming and utilizing the sameInfo
- Publication number
- CA1118381A CA1118381A CA000322982A CA322982A CA1118381A CA 1118381 A CA1118381 A CA 1118381A CA 000322982 A CA000322982 A CA 000322982A CA 322982 A CA322982 A CA 322982A CA 1118381 A CA1118381 A CA 1118381A
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- Prior art keywords
- solvent
- cellulose
- agent
- acid
- metal
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C13—SUGAR INDUSTRY
- C13K—SACCHARIDES OBTAINED FROM NATURAL SOURCES OR BY HYDROLYSIS OF NATURALLY OCCURRING DISACCHARIDES, OLIGOSACCHARIDES OR POLYSACCHARIDES
- C13K1/00—Glucose; Glucose-containing syrups
- C13K1/02—Glucose; Glucose-containing syrups obtained by saccharification of cellulosic materials
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08B—POLYSACCHARIDES; DERIVATIVES THEREOF
- C08B1/00—Preparatory treatment of cellulose for making derivatives thereof, e.g. pre-treatment, pre-soaking, activation
- C08B1/003—Preparation of cellulose solutions, i.e. dopes, with different possible solvents, e.g. ionic liquids
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C3/00—Pulping cellulose-containing materials
- D21C3/006—Pulping cellulose-containing materials with compounds not otherwise provided for
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E50/00—Technologies for the production of fuel of non-fossil origin
- Y02E50/10—Biofuels, e.g. bio-diesel
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Biochemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Health & Medical Sciences (AREA)
- Materials Engineering (AREA)
- Emergency Medicine (AREA)
- Engineering & Computer Science (AREA)
- General Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Polysaccharides And Polysaccharide Derivatives (AREA)
- Preparation Of Compounds By Using Micro-Organisms (AREA)
- Chemical Or Physical Treatment Of Fibers (AREA)
Abstract
ABSTRACT
A nontoxic cellulose solvent and process for forming and utilizing the same is disclosed. The solvent includes a metal chelating 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 precipitate cellulose therefrom. The recovered cellulose may then be hydrolyzed by cellulose enzyme or acid to yield glucose with lignin being removed either before or after hydrolysis has occurred.
A nontoxic cellulose solvent and process for forming and utilizing the same is disclosed. The solvent includes a metal chelating 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 precipitate cellulose therefrom. The recovered cellulose may then be hydrolyzed by cellulose enzyme or acid to yield glucose with lignin being removed either before or after hydrolysis has occurred.
Description
NO~TOXIC CELLULOSE SOLV~
A~D PROCESS FOR FORMI~G .~ND UTILIZI~G THE SAME
This disclosure relates to a nontoxic cellulose solvent and process for forming and utilizing a cellulose solvent including hydrolyzing recovered cellulose to yield glucose therefrom.
The utilization of cellulosic waste materials, such as cornstalks, sawdusts, straws, bagasse, and the like, has been the subject of strong interest recently, particul-arly with respect to utilization of such waste materials for developing alternate sources of fuels, feedstuffs, 10 chemicals and other useful products.
Cellulosic materials include three principal components -cellulose, hemicellulose and lignin. Methods for extrac-tion of hemicellulose have heretofore been suggested and/or utilized and such extracted hemicellulose can be 15 utilized by many existing methods including hydrolysis, fermentation, pyrolysis, and the l;ike.
Lignin has also been isolated from cellulosic materials and since it is higher in hydrogen and carbon and lower in oxygen content than celIulose and hemicellulose it 20 has the highest fuel utility of the three. Isolated lignin can be burned to generate steam and electricity and can also be used to produce a number of useful products including vanillin, dimethylsulfoxide, dimethyl ~ qk .~ ~
sulfide, and methyl mercaptan and catechol.
Recovery of cellulose and/or utilization of the same, as by hydrolysis to provide glucose, has presented a problem heretofore primarily due to the crystalline structure of the cellulose molecules and the presence therein of a lignin seal.
Attempts have been made to hydrolyze cellulose, and these attempts have included the use of acids or enzymes, but such attempts have not been completely successful, at least not in providing an economically attractive method that is capable of providing a satisfactorily high yield of glucose for the cellulose in such cellulosic materials.
Also, while solvents have been suggested and/or utilized in conjunction with cellulosic materials, improvements in such solvents can still be utilized in recovering cellulose. In this regard, dissolution of pure cellulose using a ferric sodium tartrate complex based solvent has been heretofore suggested.
This invention provides a substantially nontoxic cellulose solvent, comprising a metal chelating agent, a metal, a caustic swelling agent and a stabi]izing agent for stabilizing the solvent. The solvent has been found particularly useful in recovering cellulose from cellulosic .
B
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111831~
materials by contacting the cellulosic materials with the solvent, which may in aqueous or solid form, and precipitating cellulose therefrom. The recovered cellulose may then be hydrolyzed to yield glucose, with lignin being removed either before or after hydrolys-is has occurred.
As is well known, cellulose molecules form highly ordered crystal-line structures. In addition, in cellulosic materials, lignin in middle lamella poses as a physical seal surrounding cellulose fibres in such materials.
The nontoxic solvent of this invention is useful in contacting cel-lulosic materials to dissolve and swell the cellulose in situ, and at the same time repturing the lignin seal. This enables the cellu-lose to be recovered and makes the cellulose very accessible for hydrolysis since it is no longer protected by its crystalline structure or the lignin seal.
A good solvent to extract and dissolve cellulosic materials general-ly has the following components:
~a~ an agent to give high or low pH to loosen the 20 cellulose structure;
(b) a metal to get into the structure;
(c~ an agent that can keep the metal in solution; and (d~ sometimes, an agent to stabilize the solvent.
B
. ~, , .;
Analysis of the chemical nature of known cellulose solvents leads to a generz,lized acronym for these subst-ances oE CXXS. The i-~itial C signifies a chelating agent while the following X signifies a specific type of chelating agent. The S indicates a cellulose swelling agent while the second X specifies the particular swelling agent. The solvent described herein is composed of a metal chelating agent plus a caustic sw~lling agent.
Hence this solvent will be referred to hereinafter as lO cMcs, which denotes Chelating Metal Caustic Swelling.
A general cellulose-dissolving agent is composed of a chelating agent plus a high or low pH swelling agent.
Current economics favor the use of relatively cheap sulfuric acid as a general swelling agent along with a 15 suitable chelating agent (such as the metal ions Ca Zn , etc.). for cellulose dissolution. The inorganic caustic used in`iron tartrate solvent may be replaced by a sultable organic base. Hence, the cellulose solvent of this invention is distinct from the ferric sodium 20 tartrate based solvent mentioned hereinabove with res-pect to dissolving pure cellulose.
The solvent of this invention employs an aqueous solu-tion of 17% sodium tartrate, 6~6% ferric chloride and 7.~/0 caustic which is stabilized by 6~20/c sodium sulfite 25 (all in weight percent). All components of the solvent are easy to handle and nontoxic, which simplifies their use in the proposed process.
Addition of sodium sul~ite in the proportions indicated protects the iron in the solvent against oxidation and does not interfere with the solvent's ability to dissolve cellulose. Use of a ferric sodium tartrate based solvent (as mentioned hereinabove and described by Jayme and later by valtasaari) is not practical in the proposed process since the temperatures required to 10 evaporate the wash water also cause precipitation of the iron sodium tartrate complex with resultant loss of solvent capability. The solvent of this invention does not have this shortcoming.
An example of a particular solvent contains the following:
15 ~ ~ `6 0 about lOg ; Tartaric Acid about 17g NaOH about 229 Na~S03 about 13g + water to a total of 200g.
20 The pretreatment of the cellulosic residue involves contacting the residue with solvent in a 1:4 (residue/
solvent) weight ratio. Water is then added causing the cellulose to reprecipitate. The solvent is then washed from the residue with more water. The diluted solvent :~il83~
(wash solution) is concentrated by vacuum evaporation to its initial concentration and reused. The cellulose in the residue, having been clissolved and the reprecipit-ated in situ on removal o the solvent~ is hydrolyzed by acid or cellulase enzyme to give a quantitative yield of glucose. Lignin is preferably removed after hydrolysis but can be removed after precipitation of cellulose and before hydrolyzing the cellulose to yield glucose. In either case, the lignin is separated by filtration or 10 centrifugation.
An alternative to treating the cellulosic residue with liquid CMCS involves contacting the residue directly with a dry solvent powder. This powder is obtained by treating the liquid CMCS as described previously with 15 approximately 0.5 volumes methyl alcohol per volume of CMCS~ collecting the resulting green precipitate and drying the precipitate to a fine powder. Preliminary experiments utilizing "solid" phase dissolutant of cellulosic residues show that this is a viable approach 20 to cellulose saccharification. The dry powder is mixed thoroughly with the residue. The moisture in the residue dissolves the powder, providing intimate contact-ing of solvent and residue and leading to dissolution of cellulose in situ.
25 An economically viable process for cellulose saccharifi-83~
cation must meet two major constraints. First, the solvent must be recovered and recycled quantitatively.
Second, saccharification of the cellulose must be substantially complete. When the process as described herein employing CMCS solvent is used, both these constraints are met.
Another advantageous feature of the process is that the liquid CMCS solvent is not sensitive to the initial moisture content of the cellulosic residue used. This 10 is not the case with many other cellulose saccharifi-cation processes. Hence, the residue need not be subjected to a drying operation prior to treatment wit~
the solvent.
With regard to the solid phase solvent, several addit-15 Ional economic advantages present themselves. First, it is possible to reduce the ratio of total CMCS solvent to cel~lulosic residue required for cellulose dissolution due to more intimate mixing and contacting~ This in ~ turn reduces both capital and operating costs~ particu-20 larly in steps where the solvent is washed from theresidue. Second, a solid solvent powder also makes possible the centralized manufacture of solvent which can be shipped dry to individual plants utilizing cellu-losic materials. This obviously results in savings in 25 capltal and operating costs. Finally, since the solid 3~
powder combines with the moisture normally found in the residue to dissolve the cellulose in situ, the larger fluid volumes associated with the liquid CMCS solvent are not required and process equipment can be smaller.
Examples of the solvent and process of this invention are as follows:
In Situ Dissolution and Hydrolysis of Corn Residue ta) Preparation of CMCS Solvent:
10 Sodium tartrate, ferric chloride, sodium hydroxide and sodium sulfite are dissolved in water to give a solution containing, respectively, lP/c, 6~/o~ 7~/o and 6.2% of each of the above components. This solvent, which is capable of dissolving up to 40 grams/liter of crystall-15 ine ~-cellulose, is liquid CMCS.
Addition of 0.25 to 1. volume methanol to 1 volume of the above gives a green precipitate which, when filtered off and dried gives a green powder. ~his powder dissol- -ved in water gives a solvent which dissolves cellulose 20 and which has the same efficacy as the original solvent.
The powder is dry CMCS.
(b) Preparation of Enzyme:
Enzyme preparation "CW" was made as follows: Ten grams , 38~
g of enzyme was dissolved in 100 milliliters of water.
~ext, 57 grams of ammonium sulfate was added. Upon mixing, the ammonium sulfate dissolved and a white precipitate formed. This precipitate was separated by centrifugation and re-dissolved in 30 mil~iliters of water. The solution was then desalted using Sephadex G~25 (Pharmacia Corporation) and made up to a final volume of about 100 milliliters.
(c) In Situ Dissolution and Hydrolysis of Corn Residue 10 Corn residue, ground to greater than 40 mesh particle size, and liquid CMCS were combined in a weight ratio 1:4.9 corn residue:CMCS. After standing twelve hours water was added~ causing the cellulose in the corn residue to reprecipitate and the solvent to be washed 15 out. The solvent is recoverable.
The pretreated residue was combined with water, buffer and enzy~e preparation CW to give a solution containiny
A~D PROCESS FOR FORMI~G .~ND UTILIZI~G THE SAME
This disclosure relates to a nontoxic cellulose solvent and process for forming and utilizing a cellulose solvent including hydrolyzing recovered cellulose to yield glucose therefrom.
The utilization of cellulosic waste materials, such as cornstalks, sawdusts, straws, bagasse, and the like, has been the subject of strong interest recently, particul-arly with respect to utilization of such waste materials for developing alternate sources of fuels, feedstuffs, 10 chemicals and other useful products.
Cellulosic materials include three principal components -cellulose, hemicellulose and lignin. Methods for extrac-tion of hemicellulose have heretofore been suggested and/or utilized and such extracted hemicellulose can be 15 utilized by many existing methods including hydrolysis, fermentation, pyrolysis, and the l;ike.
Lignin has also been isolated from cellulosic materials and since it is higher in hydrogen and carbon and lower in oxygen content than celIulose and hemicellulose it 20 has the highest fuel utility of the three. Isolated lignin can be burned to generate steam and electricity and can also be used to produce a number of useful products including vanillin, dimethylsulfoxide, dimethyl ~ qk .~ ~
sulfide, and methyl mercaptan and catechol.
Recovery of cellulose and/or utilization of the same, as by hydrolysis to provide glucose, has presented a problem heretofore primarily due to the crystalline structure of the cellulose molecules and the presence therein of a lignin seal.
Attempts have been made to hydrolyze cellulose, and these attempts have included the use of acids or enzymes, but such attempts have not been completely successful, at least not in providing an economically attractive method that is capable of providing a satisfactorily high yield of glucose for the cellulose in such cellulosic materials.
Also, while solvents have been suggested and/or utilized in conjunction with cellulosic materials, improvements in such solvents can still be utilized in recovering cellulose. In this regard, dissolution of pure cellulose using a ferric sodium tartrate complex based solvent has been heretofore suggested.
This invention provides a substantially nontoxic cellulose solvent, comprising a metal chelating agent, a metal, a caustic swelling agent and a stabi]izing agent for stabilizing the solvent. The solvent has been found particularly useful in recovering cellulose from cellulosic .
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111831~
materials by contacting the cellulosic materials with the solvent, which may in aqueous or solid form, and precipitating cellulose therefrom. The recovered cellulose may then be hydrolyzed to yield glucose, with lignin being removed either before or after hydrolys-is has occurred.
As is well known, cellulose molecules form highly ordered crystal-line structures. In addition, in cellulosic materials, lignin in middle lamella poses as a physical seal surrounding cellulose fibres in such materials.
The nontoxic solvent of this invention is useful in contacting cel-lulosic materials to dissolve and swell the cellulose in situ, and at the same time repturing the lignin seal. This enables the cellu-lose to be recovered and makes the cellulose very accessible for hydrolysis since it is no longer protected by its crystalline structure or the lignin seal.
A good solvent to extract and dissolve cellulosic materials general-ly has the following components:
~a~ an agent to give high or low pH to loosen the 20 cellulose structure;
(b) a metal to get into the structure;
(c~ an agent that can keep the metal in solution; and (d~ sometimes, an agent to stabilize the solvent.
B
. ~, , .;
Analysis of the chemical nature of known cellulose solvents leads to a generz,lized acronym for these subst-ances oE CXXS. The i-~itial C signifies a chelating agent while the following X signifies a specific type of chelating agent. The S indicates a cellulose swelling agent while the second X specifies the particular swelling agent. The solvent described herein is composed of a metal chelating agent plus a caustic sw~lling agent.
Hence this solvent will be referred to hereinafter as lO cMcs, which denotes Chelating Metal Caustic Swelling.
A general cellulose-dissolving agent is composed of a chelating agent plus a high or low pH swelling agent.
Current economics favor the use of relatively cheap sulfuric acid as a general swelling agent along with a 15 suitable chelating agent (such as the metal ions Ca Zn , etc.). for cellulose dissolution. The inorganic caustic used in`iron tartrate solvent may be replaced by a sultable organic base. Hence, the cellulose solvent of this invention is distinct from the ferric sodium 20 tartrate based solvent mentioned hereinabove with res-pect to dissolving pure cellulose.
The solvent of this invention employs an aqueous solu-tion of 17% sodium tartrate, 6~6% ferric chloride and 7.~/0 caustic which is stabilized by 6~20/c sodium sulfite 25 (all in weight percent). All components of the solvent are easy to handle and nontoxic, which simplifies their use in the proposed process.
Addition of sodium sul~ite in the proportions indicated protects the iron in the solvent against oxidation and does not interfere with the solvent's ability to dissolve cellulose. Use of a ferric sodium tartrate based solvent (as mentioned hereinabove and described by Jayme and later by valtasaari) is not practical in the proposed process since the temperatures required to 10 evaporate the wash water also cause precipitation of the iron sodium tartrate complex with resultant loss of solvent capability. The solvent of this invention does not have this shortcoming.
An example of a particular solvent contains the following:
15 ~ ~ `6 0 about lOg ; Tartaric Acid about 17g NaOH about 229 Na~S03 about 13g + water to a total of 200g.
20 The pretreatment of the cellulosic residue involves contacting the residue with solvent in a 1:4 (residue/
solvent) weight ratio. Water is then added causing the cellulose to reprecipitate. The solvent is then washed from the residue with more water. The diluted solvent :~il83~
(wash solution) is concentrated by vacuum evaporation to its initial concentration and reused. The cellulose in the residue, having been clissolved and the reprecipit-ated in situ on removal o the solvent~ is hydrolyzed by acid or cellulase enzyme to give a quantitative yield of glucose. Lignin is preferably removed after hydrolysis but can be removed after precipitation of cellulose and before hydrolyzing the cellulose to yield glucose. In either case, the lignin is separated by filtration or 10 centrifugation.
An alternative to treating the cellulosic residue with liquid CMCS involves contacting the residue directly with a dry solvent powder. This powder is obtained by treating the liquid CMCS as described previously with 15 approximately 0.5 volumes methyl alcohol per volume of CMCS~ collecting the resulting green precipitate and drying the precipitate to a fine powder. Preliminary experiments utilizing "solid" phase dissolutant of cellulosic residues show that this is a viable approach 20 to cellulose saccharification. The dry powder is mixed thoroughly with the residue. The moisture in the residue dissolves the powder, providing intimate contact-ing of solvent and residue and leading to dissolution of cellulose in situ.
25 An economically viable process for cellulose saccharifi-83~
cation must meet two major constraints. First, the solvent must be recovered and recycled quantitatively.
Second, saccharification of the cellulose must be substantially complete. When the process as described herein employing CMCS solvent is used, both these constraints are met.
Another advantageous feature of the process is that the liquid CMCS solvent is not sensitive to the initial moisture content of the cellulosic residue used. This 10 is not the case with many other cellulose saccharifi-cation processes. Hence, the residue need not be subjected to a drying operation prior to treatment wit~
the solvent.
With regard to the solid phase solvent, several addit-15 Ional economic advantages present themselves. First, it is possible to reduce the ratio of total CMCS solvent to cel~lulosic residue required for cellulose dissolution due to more intimate mixing and contacting~ This in ~ turn reduces both capital and operating costs~ particu-20 larly in steps where the solvent is washed from theresidue. Second, a solid solvent powder also makes possible the centralized manufacture of solvent which can be shipped dry to individual plants utilizing cellu-losic materials. This obviously results in savings in 25 capltal and operating costs. Finally, since the solid 3~
powder combines with the moisture normally found in the residue to dissolve the cellulose in situ, the larger fluid volumes associated with the liquid CMCS solvent are not required and process equipment can be smaller.
Examples of the solvent and process of this invention are as follows:
In Situ Dissolution and Hydrolysis of Corn Residue ta) Preparation of CMCS Solvent:
10 Sodium tartrate, ferric chloride, sodium hydroxide and sodium sulfite are dissolved in water to give a solution containing, respectively, lP/c, 6~/o~ 7~/o and 6.2% of each of the above components. This solvent, which is capable of dissolving up to 40 grams/liter of crystall-15 ine ~-cellulose, is liquid CMCS.
Addition of 0.25 to 1. volume methanol to 1 volume of the above gives a green precipitate which, when filtered off and dried gives a green powder. ~his powder dissol- -ved in water gives a solvent which dissolves cellulose 20 and which has the same efficacy as the original solvent.
The powder is dry CMCS.
(b) Preparation of Enzyme:
Enzyme preparation "CW" was made as follows: Ten grams , 38~
g of enzyme was dissolved in 100 milliliters of water.
~ext, 57 grams of ammonium sulfate was added. Upon mixing, the ammonium sulfate dissolved and a white precipitate formed. This precipitate was separated by centrifugation and re-dissolved in 30 mil~iliters of water. The solution was then desalted using Sephadex G~25 (Pharmacia Corporation) and made up to a final volume of about 100 milliliters.
(c) In Situ Dissolution and Hydrolysis of Corn Residue 10 Corn residue, ground to greater than 40 mesh particle size, and liquid CMCS were combined in a weight ratio 1:4.9 corn residue:CMCS. After standing twelve hours water was added~ causing the cellulose in the corn residue to reprecipitate and the solvent to be washed 15 out. The solvent is recoverable.
The pretreated residue was combined with water, buffer and enzy~e preparation CW to give a solution containiny
2.5% residue. Incubation of the mi~ture at 45C for 45 hours gave 7~/c conversion of the ~ -cellulose to glucose.
20 Since the solvent pretreatment and subsequent cellulose reprecipitation was done without first separating the solvent containing dissolved cellulose from the solid residue, this technique was referred to as "in situ' dissolution ~and reprecipitation).
(d) In Situ Dissolution and Hydrolysis of Corn Residue - Control Study Using the same procedure as in Example l(c), corn residue was pretreated, washed, and hydrolyzed with enzyme. In 24 hours, 85% of the ~-cellulose to glucose was obtained.
As a control untreated corn residue was hydrolyzed in the same way. Conversion to glucose in this case was 2~/c.
Buildup of impurities in the solvent stream within a processing operation may be prevented by occasional precipitation of solid CMCS from the liquid stream using 10 methanol as described,above. Small molecular weight impurities would remain in solution while the C~CS solid powder was removed and purified thereby.
EXAMP~E 2 - Recovery of CMCS Solvent 15 (a) Recovery of CMCS from Bagasse;
Sugar cane bagasse mixed with CMCS in a 1:5 weight ratio (1:4 volume ratio) was washed,with water at a ratio of
20 Since the solvent pretreatment and subsequent cellulose reprecipitation was done without first separating the solvent containing dissolved cellulose from the solid residue, this technique was referred to as "in situ' dissolution ~and reprecipitation).
(d) In Situ Dissolution and Hydrolysis of Corn Residue - Control Study Using the same procedure as in Example l(c), corn residue was pretreated, washed, and hydrolyzed with enzyme. In 24 hours, 85% of the ~-cellulose to glucose was obtained.
As a control untreated corn residue was hydrolyzed in the same way. Conversion to glucose in this case was 2~/c.
Buildup of impurities in the solvent stream within a processing operation may be prevented by occasional precipitation of solid CMCS from the liquid stream using 10 methanol as described,above. Small molecular weight impurities would remain in solution while the C~CS solid powder was removed and purified thereby.
EXAMP~E 2 - Recovery of CMCS Solvent 15 (a) Recovery of CMCS from Bagasse;
Sugar cane bagasse mixed with CMCS in a 1:5 weight ratio (1:4 volume ratio) was washed,with water at a ratio of
3 volumes water to 1 volume liquid CMCS. A mass balance based on liquid chromatographic analysis of the wash 20 water showed essentially complete recovery of the solvént.
~b), Concentration of Diluted CMCS
CMCS diluted with up to 3 volumes water was re-concen-.
3~3~
trated at 35C under reduced pressure. The dilution and subsequent reconcentration had no apparent deleter-ious effect on the solvenl: activity of the CMCS.
(c) Recovery of CMCS from Crystalline ~-cellulose Crystalline ~-cellulose~ Avicell, was mixed with 5 volumes CMCS resulting in its dissolution. After standing~ the cellulose was reprecipitated and washed using 3.0 volumes water per volume CMCS. The diluted CMCS was then concentrated to its original strength 10 using evaporation at reduced pressure. The concentr-ated CMCS retained its original solvating power.
The solvent and the process of this invention thus provide that:
a. complete non-destructive hydrolysis of the cellulose 15 in the cellulosic material residue is obtaine~;
b. the process is not sensitive to the moixture content of the residue;
c. the solvent can be simply and efficiently recovered and recycled;
20 d. the solvent i9 relatively easy to handle and creates no safety problems in the work place;
e. the use of dry CMCS solvent allows direct contating of solvent and residue, saving both capital and operat-ing costs;
25 f. the pos~ibility of a centralized facility producing 3~
dry CMCS cellulose solvenl: improves the economic viability of the proposed cellulose saccharification process; and g. the cellulose is dissolved~ reprecipitated and hydrolyzed in situ by cellulase enzyme or acid.
~b), Concentration of Diluted CMCS
CMCS diluted with up to 3 volumes water was re-concen-.
3~3~
trated at 35C under reduced pressure. The dilution and subsequent reconcentration had no apparent deleter-ious effect on the solvenl: activity of the CMCS.
(c) Recovery of CMCS from Crystalline ~-cellulose Crystalline ~-cellulose~ Avicell, was mixed with 5 volumes CMCS resulting in its dissolution. After standing~ the cellulose was reprecipitated and washed using 3.0 volumes water per volume CMCS. The diluted CMCS was then concentrated to its original strength 10 using evaporation at reduced pressure. The concentr-ated CMCS retained its original solvating power.
The solvent and the process of this invention thus provide that:
a. complete non-destructive hydrolysis of the cellulose 15 in the cellulosic material residue is obtaine~;
b. the process is not sensitive to the moixture content of the residue;
c. the solvent can be simply and efficiently recovered and recycled;
20 d. the solvent i9 relatively easy to handle and creates no safety problems in the work place;
e. the use of dry CMCS solvent allows direct contating of solvent and residue, saving both capital and operat-ing costs;
25 f. the pos~ibility of a centralized facility producing 3~
dry CMCS cellulose solvenl: improves the economic viability of the proposed cellulose saccharification process; and g. the cellulose is dissolved~ reprecipitated and hydrolyzed in situ by cellulase enzyme or acid.
Claims (22)
1. A substantially nontoxic cellulose solvent, comprising a metal chelating agent, a metal, a caustic swelling agent and a stabilizing agent stabilizing the solvent.
2. The solvent of claim 1, wherein said solvent is a dry powder.
3. The solvent of claim 1, wherein said metal chelating agent is sodium tartrate, said metal is ferric chloride, and sodium sulfite is the stabilizing agent.
4. The solvent of claim 3, wherein said solvent includes 17% sodium tartrate, 6.6% ferric chloride, and 7.8% caustic stabilized by 6.2% sodium sulfite.
5. The solvent of claim 1, wherein said caustic swelling agent provides a high or low pH to loosen the cellulose structure of contacted cellulose material, and said solvent includes a maintaining agent keeping said metal in solution.
6. The solvent of claim 5, wherein said maintain-ing agent is selected from the group consisting of tartar-ic acid, citric acid, and gluconic acid.
7. The solvent of claim 5, wherein said maintaining agent is tartrate acid, wherein said metallic agent is FeC13, wherein said loosening agent is NaOH, and wherein said stabilizing agent is Na2SO3.
8. The solvent of claim 7, wherein said solvent includes about 10g of FeC13.6H20, about 17g of tartaric acid, about 22g of NaOH, about 13g of Na2SO3 and water to a total of about 200g.
9. A method for preparing a substantially nontoxic aqueous, cellulose solvent, comprising: adding tartaric acid to ferric chloride in water; adding sodium hydroxide;
and adding sodium sulfite to stabilize the aqueous solvent.
and adding sodium sulfite to stabilize the aqueous solvent.
10. A method for preparing a solid cellulose solvent, said method comprising: preparing a CMCS cellulose solvent in liquid form; precipitating said solvent; and separating said precipitate from the solution out of which it was precipitated.
11. The method of claim 9, wherein said solvent is precipitated using about 0.25 to about 1.0 volumes of methyl alcohol for each volume of solvent.
12. A process for recovering cellulose from cellul-osic materials, said process comprising: providing a chelating metal caustic swelling solvent that includes sodium tartrate, ferric chloride and caustic stabilized by sodium sulfite; contacting said cellulosic with said solvent; and precipitating cellulose from cellulosic materials contacted by said solvent.
13. The process of claim 12, wherein said solvent is an aqueous solvent contacting said cellulosic materials.
14. The process of claim 12, wherein said solvent is in solid form and intermixed with said cellulosic mat-erials.
15. The process of claim 12, wherein said cellulosic materials are contacted with solvent with about a 1 to 4 weight ratio of materials to solvent.
16. The process of claim 12, wherein said precipit-ation of cellulose is effected by addition of water.
17. The process of claim 16, wherein said solvent is recovered from said water for reuse by being concen-trated by vacuum evaporation to its initial concentration.
18. The process of claim 12, wherein said cellulose is hydrolyzed by acid and or cellulase enzyme to yield glucose.
19. A process for yielding glucose from cellulose recovered from cellulosic materials, said process comprising:
providing a chelating metal caustic swelling solvent; con-tacting said cellulosic materials with said solvent;
precipitating cellulose from said cellulosic materials contacted by said solvent; and hydrolyzinq said cellulose by acid and or cellulase enzyme to yield glucose.
providing a chelating metal caustic swelling solvent; con-tacting said cellulosic materials with said solvent;
precipitating cellulose from said cellulosic materials contacted by said solvent; and hydrolyzinq said cellulose by acid and or cellulase enzyme to yield glucose.
20. The process of claim 19, wherein the solvent stream is purified by the occasional precipitation of solid CMCS
by methanol to remove impurities.
by methanol to remove impurities.
21. The process of claim 19, wherein lignin is separated by filtration or centrifugation after hydroly-zing to yield glucose.
22. The process of claim 12, wherein said cellulose in left in-situ and subsequently hydrolzed by acid, enzyme, or by a sequence involving both acid and enzyme.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US88447778A | 1978-03-08 | 1978-03-08 | |
| US884,477 | 1978-03-08 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1118381A true CA1118381A (en) | 1982-02-16 |
Family
ID=25384699
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000322982A Expired CA1118381A (en) | 1978-03-08 | 1979-03-08 | Nontoxic cellulose solvent and process for forming and utilizing the same |
Country Status (12)
| Country | Link |
|---|---|
| JP (1) | JPS54154484A (en) |
| AU (1) | AU527242B2 (en) |
| BR (1) | BR7901382A (en) |
| CA (1) | CA1118381A (en) |
| DE (1) | DE2908992A1 (en) |
| FI (1) | FI790788A (en) |
| FR (1) | FR2419350A1 (en) |
| GB (1) | GB2018777B (en) |
| MX (1) | MX150035A (en) |
| PH (1) | PH15126A (en) |
| SE (1) | SE439931B (en) |
| ZA (1) | ZA79912B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2012125174A (en) * | 2010-12-14 | 2012-07-05 | Meiji Univ | Method for producing glucose |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2959500A (en) * | 1956-02-14 | 1960-11-08 | Schweizerische Eidgenossenschaft | Process for the saccharification of cellulose and cellulosic materials |
| GB893822A (en) * | 1958-02-27 | 1962-04-11 | Carl Freudenberg K G A A | Improvements relating to the production of aqueous cellulose gels and sols |
-
1979
- 1979-02-26 ZA ZA79912A patent/ZA79912B/en unknown
- 1979-02-28 GB GB7907043A patent/GB2018777B/en not_active Expired
- 1979-02-28 AU AU44701/79A patent/AU527242B2/en not_active Ceased
- 1979-03-02 SE SE7901898A patent/SE439931B/en not_active IP Right Cessation
- 1979-03-06 DE DE2908992A patent/DE2908992A1/en not_active Withdrawn
- 1979-03-07 MX MX176831A patent/MX150035A/en unknown
- 1979-03-07 JP JP2660079A patent/JPS54154484A/en active Pending
- 1979-03-07 FI FI790788A patent/FI790788A/en not_active Application Discontinuation
- 1979-03-07 BR BR7901382A patent/BR7901382A/en unknown
- 1979-03-08 PH PH22267A patent/PH15126A/en unknown
- 1979-03-08 CA CA000322982A patent/CA1118381A/en not_active Expired
- 1979-03-08 FR FR7906022A patent/FR2419350A1/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| BR7901382A (en) | 1979-10-02 |
| AU4470179A (en) | 1979-09-13 |
| DE2908992A1 (en) | 1979-09-13 |
| FR2419350A1 (en) | 1979-10-05 |
| SE439931B (en) | 1985-07-08 |
| PH15126A (en) | 1982-08-16 |
| MX150035A (en) | 1984-03-05 |
| AU527242B2 (en) | 1983-02-24 |
| GB2018777A (en) | 1979-10-24 |
| SE7901898L (en) | 1979-09-09 |
| ZA79912B (en) | 1980-02-27 |
| FI790788A (en) | 1979-09-09 |
| GB2018777B (en) | 1983-03-30 |
| JPS54154484A (en) | 1979-12-05 |
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