CA1119982A - Process for recovering and utilizing cellulose using sulfuric acid - Google Patents
Process for recovering and utilizing cellulose using sulfuric acidInfo
- Publication number
- CA1119982A CA1119982A CA000322981A CA322981A CA1119982A CA 1119982 A CA1119982 A CA 1119982A CA 000322981 A CA000322981 A CA 000322981A CA 322981 A CA322981 A CA 322981A CA 1119982 A CA1119982 A CA 1119982A
- Authority
- CA
- Canada
- Prior art keywords
- cellulose
- sulfuric acid
- acid
- residue
- dilute
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
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
-
- 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
- D21C3/04—Pulping cellulose-containing materials with acids, acid salts or acid anhydrides
Abstract
Abstract A process is disclosed for recovering cellulose using sulfuric acid and utilizing the recovered cellulose by hydrolyzing to yield glucose. Cellu-losic raw materials are hydrolyzed by dilute sulfuric acid to remove hemicellulose, after which the solid residue is separated and concentrated sulfuric aicd is added thereto to dissolve cellulose in the solid residue. After blending and mixing of the resi-due in the concentrated sulfuric acid under closely controlled reaction conditions, cellulose is repre-cipitated by addition of water or an organic solvent such as methanol. The recovered cellulose can then be hydrolyzed by cellulase enzymes and/or dilute acids to provide a high yield of glucose. High level re-covery and reconcentration of the sulfuric acid is also disclosed.
Description
Process for Recovering_and Utilizing Cellulose Using Sulfuric Acid This invention relates to a process for recovering cellulose from cellulosic materials, said process comprising: hydrolyz-ing cellulosic ma-terials with dilute acid at about 1~1C and removing hemicellulose; adding concentrated acid -to said res-idue to dissolve cellulose therein at room temperature; blend-ing and mixing said residue in said concentra-ted acid; and reprecipitating said cellulose by dilu-ting said acid with a selected solvent.
The utilization of cellulosic waste materials, such as corn-stalk, sawdusts, straws, bagasse, and the like, has been the subject of strong i.nterest recently, particularly with respect to utilization of such waste materials for developing alternate sources of fuels, feeds~uff, chemicals and other useful products.
Cellulosic materials include three principle components --cellulose, hemicellulose and lignin. Methods for extraction of hemicellulose have heretofore been suggested and/or util-ized and such extracted hemicellulose can be utilized by many existing methods including hydrolysis t fermentation, pyrolsis, and the like.
Lignin has also been isolated from cellulosic materials and since it is higher in hydrogen and carbon and lower in oxygen content than cellulose and hemicellulose it has the highest fuel of the three. Isolated lignin can ----------Bl .
be burned to generate steam and electricity and canalso be used to produce a number of useEul products including v~nillin, dimethylsulfoxide, dimethyl sul-fide, and methyl mercaptan and catechol.
5 Recovery of cellulose and/or utilization of the same, as by hydrolysis to provide glucose, has presented a problem heretofore primarily due to the crystalling structure o~ the cellulos~ molecules and the presence therein of a lignin seal.
10 Attempts have been made to hydrolyze cellulose, and these attempts have included the use of acids or en-zymes, but such attempts have not been completely successful, at least not in providing an economically attractive method that is capable o~ providing a sat-lS isfactorily high yield of glucose for the.cellulosein such cellulosic materials.
The use of acids including sulfuric acid in hydrolysis o~ cellulosic materials to produce glucose has been known for many decades. In general, all previously 20 reported processes of cellulose hydrolysis using sul-furic aci.d can be classified illtO two large groups;
Those using dilute sulfuric acid and those usi.ng con-centrated sul.furic acid. The dilute acicl process typically involves a sulfuric aci.d solution containing ,. _ somewhere from 5 to 50 grams of H2S04 in a kilogram of aqueous solution. At a temperature of somewhere from 150C to 350C, cellulosic materials such as wood chips suspended in the dilute acid will be hydro-S lyzed to produce glucose from cellulose and five car~bong sugars from hemicellulose. Since the reaction temperature is usually above the boiling point of the dilute acid, the hydrolysis reaction has to be carried out in pressurized reactors. At a high t mperature, glucose and five carbon sugars will also be catalyzed by the acid to form furfural and its derivatives which often react further to form undesirable by-products.
The dilute acid process has thus not been generally successful in obtaining glucose from cellulose in high yields and at low costs~ Typically, a dilute acid process gives a glucose yield of about 50% or less based upon available cellulose, hampered by the forma-tion of useless by-products. The dilute acid processes have been well known and extensi~ely studied by many researchers.
There are also a number of reports on processes of cellulose hydrolysis using concentrated sulfuric acid.
For instance, there is a relatively recent report by Bose et al. ~See Bharaki Bose, T.R. Ingle and J.L.
Bose, "Saccharification of Groundnut Shell Pulp with Sulfuric Acid", Indian Journal of Technoloyy,Vol. II, September 1973, Pages 391-393) and an earlier report by Dunning and La-throp (See J.W. Dunning and E.C.
Lathrop, "The Saccharification of Agricultural Resi-dues", Industrial and Enyineering Chemistry, Vol. 37 1945, Pages 24-29). In general, a concentrated sul-furic acid containing typically 750 grams of H2SO4 in a kilogram of acid was added to a finely divided cel-lulosic matexial. After soaking and much blending and mixing, 8 ~o 10 volumes of water was added to di-1~ lute the acid. The mixture was then refluxed for a fewhours at atmospheric pressure ~o produce glucose.
Typically, 90~ to 93~ yie]d of glucose based upon available cellulose can be obtained by this method with-out much byproduct formation. The previously reported concentrated sulfuric acid processes, however, suf~Eer Erom the fact that a large amount of acid is used.
After the completion of the hydrolysis, both the acid and the glucose are dissolved in the same aqueous sol-ution. An equally large amount of alkali (usually lime) must then be utilized to n~utralize the acid before the sugars can be utilized as, for example, a carbon source in a yeast fermentation. In these pro-cesses, the pro~lem of disposal of a large amount of calcium sulfate as a by-product must be faced in ad-dition to the high costs for purchasing both tha acidand the alkali.
This invention provides an improved process for re-covering cellulose from cellulosic materials utilizing acid~ preferably sulfuric acid, and the recovered cel-lulose may be hydrolyzed to yield glucose. The pre-5 fer,red porcess includes hydrolyzing cellulose materialwith dilute acid, removing liquid hemicellulose hydro-lysate, and adding concentrated acid, blending and mix-ing the remaining hydxolysate in the concentrated acid, and then reprecipitating the cellulose by dilut~
10 ing the acid with water or an organic solvent such as methanol. The acid utilized is preferably sulfuric acid which may be recovered to a high degree, and the recovered cellulose is hydrolyzed with either cel-lulase enzymes, or dilute acids or combinations o~
15 enzymes and acids to provide a high yield of glucose.
This disclosure provides an improved process utilizing sulfuric acid for xecovering cellulose from available cellulosic materials with much o~ the acid recovered for recycle and thus enabling a low chemical cost.
20 A high yield of glucose is obtained from the recovered cellulose by hydrolyzing the cellulose with cellu-lase enzymes and/or dilute acids.
In the process of this invention, cellulosic raw ma-terials/ such as corn stover, is first hydrolyzed with 25 either fresh or recycled dilute sulfuric acid under mild conditions to remove hemicellulose, This step involves well known reac~ion conditions (typically 1.9~ H2~O4 at 121C for 50 minutes). The liquid hemi-cellulose hydrolysate, a~ter neutrali2ation with lime, S can be used as a fermentation medium. This step is typically illustrated by the following example:
Preparation of Lignocellulose 10 grams o corn residue (mesh size larger than 40) is blended in 500 milliliters normal sulfuric acid solu-tion. It is heated up in a two liter beaker with con-denser, then mildly boiled or one hourO Afterwards it is filtered and washed with one liter hot water in a glass filter, then washed with acetone till all the color comes out. It is transferred onto a piece of aluminum foil and may be optionally air dried over-night.
The solid residue containing mostly cellulose and lignin, is filtered or cetrifuged to remove the hemi-~ellulose hydrolysate.
Then a concentrated sulfuric acid is added with the acid strength being preferably between about 60 to 90% (a 60% sulfuric acid contains 600 gram H~SO4 in 1000 grams of acid solution). At this acid strength, cellulose can be dissolved in the acid solution. This --7~
step is illustrated by t:he following exampl~s:
Example 1 One millili~er 70~ sulfuric acid is occasionally stir-B red with 0.4 gram ~vicel (microcrystal.line cellulose 5 from FMC Corp.T~pe PH101) for half an hour at room temperature, then dilute with 3 ml CH30F~ (99~ reagent grade). The mixture is filtered, there is 0.3% sugar loss in the filtrate. (As determined by the well ]cnown Anthrone method). Then the mixture is washed with water 10 until slightly acidic~ 3.6 milligrams of this pre-treated amorphous cellulose is taken out, and added 0.4 milliliter NaCH3COO PH=5 bu~fer solution and 0.04 milliliter cellulase enzyme, 90~ conversion of the cellulose to glucose can be achieved in the ~irst three 15 hours.
Example 2 The procedure and reagents are the same as Example 1, except 4 ml H20 is used to dilute the acid mixture instead of 3ml C~30H. Then the sugar loss in the fil-20 trate is 7.8% and the solid residue has the same acces-sibility to enzyme as in Example 1.
Example 3 0,6 milliliter 65% H2S04 is mixed with 0.1 gm ligno-cellulose (prepared by the pretreatment step described above) and sub~ected to the same procedure as Example 1, except it is diluted ~ith 2 milliliter CH30H, there is 1.03~ sugar loss in the filtrate, and 90~ cellulosP
conversion can be achieved within ten hours.
5 The wet mixture is then blended and mixed (during this blending and mixing, most of the cellulose is dissol-ved into the concentrated acid~ in the presence of the concentrated sulfuric acid and by a close control of the reaction conditions including temperature t time, 10 acid strength, and acid-to-solid ration. Cellulose is then re-precipitated out by diluting the acid with 2 to 5 volumes of water or an organic solvent such as methanol upon the completion of the blending and mixing.
Close control of the reaction conditions is important 15 and is the key to successful recovery of sulfuric acid and effectlve hydrolyzing of the re-precipitated cel-lulose to yield glucose. If, for example, the reaction time is too long, cellulose molecules may be hydrolyzed too far and a large portion of it be.comes solubilized 20 since cellodextrins oE DP ~deyree of polymerizationj less than 7 are soluble in water. When this occurs, that portion of the carbohydrates is l.ost because there is no easy and inexpensive way of separating soluble sugars from sulfuric acid. It is believed that this is 25 the main reason that makes known concentrated sulfuric ., acid processes of cellulose hydrolysis unworkable due to the large expenses for the acid and also an alkali to neutralize the acid in order to make a good use of the soluble sugars.
5 In this invention, with a proper control of the reac-tion conditions when the cellulose-lignin mixture is blended and ~umbled together with a concentra~ed sul-furic acid, it has been found that 97% or so by weight of the initial cellulose will be in a solid form after 10 addition oE 2 to 5 volumes of water to the mixture upon the completion of the blending and tumbling. If an organic solvent such as methanol is added instead of water, even a higher percentage (i.e. larger than 97~
or so) of the initial cellulose will b~e reprecipitated.
15 ~lso in this invention, immediately af~er addition of
The utilization of cellulosic waste materials, such as corn-stalk, sawdusts, straws, bagasse, and the like, has been the subject of strong i.nterest recently, particularly with respect to utilization of such waste materials for developing alternate sources of fuels, feeds~uff, chemicals and other useful products.
Cellulosic materials include three principle components --cellulose, hemicellulose and lignin. Methods for extraction of hemicellulose have heretofore been suggested and/or util-ized and such extracted hemicellulose can be utilized by many existing methods including hydrolysis t fermentation, pyrolsis, and the like.
Lignin has also been isolated from cellulosic materials and since it is higher in hydrogen and carbon and lower in oxygen content than cellulose and hemicellulose it has the highest fuel of the three. Isolated lignin can ----------Bl .
be burned to generate steam and electricity and canalso be used to produce a number of useEul products including v~nillin, dimethylsulfoxide, dimethyl sul-fide, and methyl mercaptan and catechol.
5 Recovery of cellulose and/or utilization of the same, as by hydrolysis to provide glucose, has presented a problem heretofore primarily due to the crystalling structure o~ the cellulos~ molecules and the presence therein of a lignin seal.
10 Attempts have been made to hydrolyze cellulose, and these attempts have included the use of acids or en-zymes, but such attempts have not been completely successful, at least not in providing an economically attractive method that is capable o~ providing a sat-lS isfactorily high yield of glucose for the.cellulosein such cellulosic materials.
The use of acids including sulfuric acid in hydrolysis o~ cellulosic materials to produce glucose has been known for many decades. In general, all previously 20 reported processes of cellulose hydrolysis using sul-furic aci.d can be classified illtO two large groups;
Those using dilute sulfuric acid and those usi.ng con-centrated sul.furic acid. The dilute acicl process typically involves a sulfuric aci.d solution containing ,. _ somewhere from 5 to 50 grams of H2S04 in a kilogram of aqueous solution. At a temperature of somewhere from 150C to 350C, cellulosic materials such as wood chips suspended in the dilute acid will be hydro-S lyzed to produce glucose from cellulose and five car~bong sugars from hemicellulose. Since the reaction temperature is usually above the boiling point of the dilute acid, the hydrolysis reaction has to be carried out in pressurized reactors. At a high t mperature, glucose and five carbon sugars will also be catalyzed by the acid to form furfural and its derivatives which often react further to form undesirable by-products.
The dilute acid process has thus not been generally successful in obtaining glucose from cellulose in high yields and at low costs~ Typically, a dilute acid process gives a glucose yield of about 50% or less based upon available cellulose, hampered by the forma-tion of useless by-products. The dilute acid processes have been well known and extensi~ely studied by many researchers.
There are also a number of reports on processes of cellulose hydrolysis using concentrated sulfuric acid.
For instance, there is a relatively recent report by Bose et al. ~See Bharaki Bose, T.R. Ingle and J.L.
Bose, "Saccharification of Groundnut Shell Pulp with Sulfuric Acid", Indian Journal of Technoloyy,Vol. II, September 1973, Pages 391-393) and an earlier report by Dunning and La-throp (See J.W. Dunning and E.C.
Lathrop, "The Saccharification of Agricultural Resi-dues", Industrial and Enyineering Chemistry, Vol. 37 1945, Pages 24-29). In general, a concentrated sul-furic acid containing typically 750 grams of H2SO4 in a kilogram of acid was added to a finely divided cel-lulosic matexial. After soaking and much blending and mixing, 8 ~o 10 volumes of water was added to di-1~ lute the acid. The mixture was then refluxed for a fewhours at atmospheric pressure ~o produce glucose.
Typically, 90~ to 93~ yie]d of glucose based upon available cellulose can be obtained by this method with-out much byproduct formation. The previously reported concentrated sulfuric acid processes, however, suf~Eer Erom the fact that a large amount of acid is used.
After the completion of the hydrolysis, both the acid and the glucose are dissolved in the same aqueous sol-ution. An equally large amount of alkali (usually lime) must then be utilized to n~utralize the acid before the sugars can be utilized as, for example, a carbon source in a yeast fermentation. In these pro-cesses, the pro~lem of disposal of a large amount of calcium sulfate as a by-product must be faced in ad-dition to the high costs for purchasing both tha acidand the alkali.
This invention provides an improved process for re-covering cellulose from cellulosic materials utilizing acid~ preferably sulfuric acid, and the recovered cel-lulose may be hydrolyzed to yield glucose. The pre-5 fer,red porcess includes hydrolyzing cellulose materialwith dilute acid, removing liquid hemicellulose hydro-lysate, and adding concentrated acid, blending and mix-ing the remaining hydxolysate in the concentrated acid, and then reprecipitating the cellulose by dilut~
10 ing the acid with water or an organic solvent such as methanol. The acid utilized is preferably sulfuric acid which may be recovered to a high degree, and the recovered cellulose is hydrolyzed with either cel-lulase enzymes, or dilute acids or combinations o~
15 enzymes and acids to provide a high yield of glucose.
This disclosure provides an improved process utilizing sulfuric acid for xecovering cellulose from available cellulosic materials with much o~ the acid recovered for recycle and thus enabling a low chemical cost.
20 A high yield of glucose is obtained from the recovered cellulose by hydrolyzing the cellulose with cellu-lase enzymes and/or dilute acids.
In the process of this invention, cellulosic raw ma-terials/ such as corn stover, is first hydrolyzed with 25 either fresh or recycled dilute sulfuric acid under mild conditions to remove hemicellulose, This step involves well known reac~ion conditions (typically 1.9~ H2~O4 at 121C for 50 minutes). The liquid hemi-cellulose hydrolysate, a~ter neutrali2ation with lime, S can be used as a fermentation medium. This step is typically illustrated by the following example:
Preparation of Lignocellulose 10 grams o corn residue (mesh size larger than 40) is blended in 500 milliliters normal sulfuric acid solu-tion. It is heated up in a two liter beaker with con-denser, then mildly boiled or one hourO Afterwards it is filtered and washed with one liter hot water in a glass filter, then washed with acetone till all the color comes out. It is transferred onto a piece of aluminum foil and may be optionally air dried over-night.
The solid residue containing mostly cellulose and lignin, is filtered or cetrifuged to remove the hemi-~ellulose hydrolysate.
Then a concentrated sulfuric acid is added with the acid strength being preferably between about 60 to 90% (a 60% sulfuric acid contains 600 gram H~SO4 in 1000 grams of acid solution). At this acid strength, cellulose can be dissolved in the acid solution. This --7~
step is illustrated by t:he following exampl~s:
Example 1 One millili~er 70~ sulfuric acid is occasionally stir-B red with 0.4 gram ~vicel (microcrystal.line cellulose 5 from FMC Corp.T~pe PH101) for half an hour at room temperature, then dilute with 3 ml CH30F~ (99~ reagent grade). The mixture is filtered, there is 0.3% sugar loss in the filtrate. (As determined by the well ]cnown Anthrone method). Then the mixture is washed with water 10 until slightly acidic~ 3.6 milligrams of this pre-treated amorphous cellulose is taken out, and added 0.4 milliliter NaCH3COO PH=5 bu~fer solution and 0.04 milliliter cellulase enzyme, 90~ conversion of the cellulose to glucose can be achieved in the ~irst three 15 hours.
Example 2 The procedure and reagents are the same as Example 1, except 4 ml H20 is used to dilute the acid mixture instead of 3ml C~30H. Then the sugar loss in the fil-20 trate is 7.8% and the solid residue has the same acces-sibility to enzyme as in Example 1.
Example 3 0,6 milliliter 65% H2S04 is mixed with 0.1 gm ligno-cellulose (prepared by the pretreatment step described above) and sub~ected to the same procedure as Example 1, except it is diluted ~ith 2 milliliter CH30H, there is 1.03~ sugar loss in the filtrate, and 90~ cellulosP
conversion can be achieved within ten hours.
5 The wet mixture is then blended and mixed (during this blending and mixing, most of the cellulose is dissol-ved into the concentrated acid~ in the presence of the concentrated sulfuric acid and by a close control of the reaction conditions including temperature t time, 10 acid strength, and acid-to-solid ration. Cellulose is then re-precipitated out by diluting the acid with 2 to 5 volumes of water or an organic solvent such as methanol upon the completion of the blending and mixing.
Close control of the reaction conditions is important 15 and is the key to successful recovery of sulfuric acid and effectlve hydrolyzing of the re-precipitated cel-lulose to yield glucose. If, for example, the reaction time is too long, cellulose molecules may be hydrolyzed too far and a large portion of it be.comes solubilized 20 since cellodextrins oE DP ~deyree of polymerizationj less than 7 are soluble in water. When this occurs, that portion of the carbohydrates is l.ost because there is no easy and inexpensive way of separating soluble sugars from sulfuric acid. It is believed that this is 25 the main reason that makes known concentrated sulfuric ., acid processes of cellulose hydrolysis unworkable due to the large expenses for the acid and also an alkali to neutralize the acid in order to make a good use of the soluble sugars.
5 In this invention, with a proper control of the reac-tion conditions when the cellulose-lignin mixture is blended and ~umbled together with a concentra~ed sul-furic acid, it has been found that 97% or so by weight of the initial cellulose will be in a solid form after 10 addition oE 2 to 5 volumes of water to the mixture upon the completion of the blending and tumbling. If an organic solvent such as methanol is added instead of water, even a higher percentage (i.e. larger than 97~
or so) of the initial cellulose will b~e reprecipitated.
15 ~lso in this invention, immediately af~er addition of
2 to 5 volumes of water or an organic solvent such as methanol, the entire mixture is 'filtered or centrifu-ged to recover some 90% or more o~ the diluted sulEur-ic acid which is re-concentrated in an evaporator to 20 remove excess water or the added methanol before re-cycle. The filter or centri;Euge cake i5 then washed with water to generate a dilute acid which can be re-cycled to the early step of hemicellulose hydrolysis described above.
The cellulose, even though in a solid form, has now been partially hydrolyzed to a lower DP than vrigi-nally and has its internal structures and lignin seals totally disrupted, and thus can be readily and com-5 pletely hydrolyzed to glucose by a dilute acid and/orby cellulase enzymes after pEI adjustment.
As can be appreciated from the foregoing, the process of this invention take~ advantage of the fact that be-fore overly hydrolyzed to become soluble, cellulose 10 molecules can ba re-precipitated from;~a concentrated sul~uric acid solution by dilution with water or an organic solvent such as methanol. The reprecipitated cellulose can be readily and completely hydrolyzed by enzymes and/or dilute acids to glucose. The repreci-lS pitation allows the separation and thus allows a highlevel of acid recycle which cuts down the chemical cost drastically.
The cellulose, even though in a solid form, has now been partially hydrolyzed to a lower DP than vrigi-nally and has its internal structures and lignin seals totally disrupted, and thus can be readily and com-5 pletely hydrolyzed to glucose by a dilute acid and/orby cellulase enzymes after pEI adjustment.
As can be appreciated from the foregoing, the process of this invention take~ advantage of the fact that be-fore overly hydrolyzed to become soluble, cellulose 10 molecules can ba re-precipitated from;~a concentrated sul~uric acid solution by dilution with water or an organic solvent such as methanol. The reprecipitated cellulose can be readily and completely hydrolyzed by enzymes and/or dilute acids to glucose. The repreci-lS pitation allows the separation and thus allows a highlevel of acid recycle which cuts down the chemical cost drastically.
Claims (20)
1. A process for recovering cellulose from cellu-losic materials, said process comprising: hydrolyzing cellulosic materials with dilute acid at about 121°C
and removing hemicellulose; adding concentrated acid to said residue to dissolve cellulose therein at room temp-erature; blending and mixing said residue in said concen-trated acid; and reprecipitating said cellulose by di-luting said acid with a selected solvent.
and removing hemicellulose; adding concentrated acid to said residue to dissolve cellulose therein at room temp-erature; blending and mixing said residue in said concen-trated acid; and reprecipitating said cellulose by di-luting said acid with a selected solvent.
2. The process of Claim 1 wherein said dilute acid and said concentrated acid is sulfuric acid.
3. The process of Claim 2 wherein said concentrated sulfuric acid has the strength of about 60 to 90%.
4. The process of Claim 2 wherein said blending and mixing of said residue in said concentrated sulfuric acid includes close control of the reaction conditions.
5. The process of Claim 1 wherein the solvent is water and about 2 to 5 volumes of water are added to said concentrated sulfuric acid to reprecipitate said cellulose.
6. The process of Claim 1 wherein said solvent is methanol.
7. The process of Claim 5 wherein about 97% by weight of cellulose is reprecipitated in solid form.
8. The process of Claim 1 wherein said concen-trated acid is recovered after addition of said solvent thereto and reconcentrated.
9. The process of Claim 8 wherein a high level of acid recycle is achieved.
10. The process of Claim 9 wherein about 90% or more of said acid is recycled.
11. The process of Claim 1 wherein said repreci-pitated cellulose has a lowered DP and has its inter-nal structure and lignin seal disrupted whereby said cellulose may be readily substantially completely hydrolyzed to yield glucose.
12. The process of Claim 11 wherein said hydro-lysis of cellulose to glucose is effected by cellu-lase enzymes.
13. The process of claim 1 wherein liquid hemicel-lulose hydrolysate is formed by hydrolyzing the cellu-losic materials with dilute acid, which after neutrali-zation with lime, may be used as a fermentation medium.
14. A process for recovering cellulose from cellu-losic materials, said process comprising: hydrolyzing cellulosic materials with dilute sulfuric acid at about 121°C to remove hemicellulose; separating solid residue including cellulose and lignin after removal of hemicel-lulose by one of filtration and centrifugation; adding concentrated sulfuric acid having a strength of between about 60% to 90% to said solid residue to dissolve the cellulose therein at room temperature; blending and mixing said solid material in said concentrated sul-furic acid under closely controlled reaction conditions;
and reprecipitating the cellulose by addition of a sel-ected solvent to said concentrated sulfuric acid after blending and mixing of said solid residue therein.
and reprecipitating the cellulose by addition of a sel-ected solvent to said concentrated sulfuric acid after blending and mixing of said solid residue therein.
15. A process for providing a high yield of glu-cose from cellulose recovered from cellulosic materials, said process comprising: hydrolyzing cellulose materials with dilute sulfuric acid to remove hemicellulose at about 121°C; separating the solid residue after removal of hemicellulose; adding concentrated sulfuric acid to said residue to dissolve cellulose therein at room temp-erature; blending and mixing said residue in said con-centrated sulfuric acid; reprecipitating said cellulose by diluting said sulfuric with acid water or solvent such as methanol; and hydrolyzinq said cellulose by exposure to cellulase enzymes to yield glucose therefrom.
16. A process for providing a high yield of glu-cose from cellulose recovered from cellulose materials, said process comprising: hydrolyzing cellulose mater-ials with dilute sulfuric acid to remove hemicellulose at about 121°C; separating the solid residue after re-moval of hemicellulose; adding concentrated sulfuric acid to said residue to dissolve cellulose therein at room temperature; blending and mixing said residue in said concentrated sulfuric acid; reprecipitating said cellulose by diluting said sulfuric acid with water or solvent such as methanol; and hydrolyzing said cellulose by exposure to dilute acids to yield glucose therefrom.
17. A process according to Claim 16 in which said hydrolysis is achieved by exposing said cellulose to a combination of dilute acid and cellulose enzymes.
18. A process for recovering cellulose from cellu-losic materials, said process comprising: hydrolyzing cellulosic materials with dilute sulfuric acid to re-move hemicellulose at about 121°C; separating solid residue including cellulose and lignin after removal of liquid hemicellulose hydrolysate by one of filtra-tion and centrifugation; washing the wet solid residue and removing the washing liquid from the residue by filtration, centrifugation, drying and/or evaporation;
adding concentrated sulfuric acid having a strength of between about 60% to 90% to said solid residue to dis-solve the cellulose therein at room temperature; blend-ing and mixing said solid material in said concentrated sulfuric acid under closely controlled reaction condi-tions; and reprecipitating the cellulose by addition of a selected solvent to said concentrated sulfuric acid after blending and mixing of said solid residue therein.
adding concentrated sulfuric acid having a strength of between about 60% to 90% to said solid residue to dis-solve the cellulose therein at room temperature; blend-ing and mixing said solid material in said concentrated sulfuric acid under closely controlled reaction condi-tions; and reprecipitating the cellulose by addition of a selected solvent to said concentrated sulfuric acid after blending and mixing of said solid residue therein.
19. The process of Claim 11 wherein said hydro-lysis of cellulose to glucose is effected by cellulase.
20. The process of Claim 11 wherein said hydro-lysis of cellulose o glucose is effected by cellulase enzymes and dilute acids.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US88448078A | 1978-03-08 | 1978-03-08 | |
| US884,480 | 1978-03-08 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1119982A true CA1119982A (en) | 1982-03-16 |
Family
ID=25384705
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000322981A Expired CA1119982A (en) | 1978-03-08 | 1979-03-08 | Process for recovering and utilizing cellulose using sulfuric acid |
Country Status (12)
| Country | Link |
|---|---|
| JP (1) | JPS54160801A (en) |
| AU (1) | AU521301B2 (en) |
| BR (1) | BR7901385A (en) |
| CA (1) | CA1119982A (en) |
| DE (1) | DE2908993A1 (en) |
| FI (1) | FI65801C (en) |
| FR (1) | FR2419351A1 (en) |
| GB (1) | GB2017710B (en) |
| MX (1) | MX151469A (en) |
| PH (1) | PH15122A (en) |
| SE (1) | SE7901899L (en) |
| ZA (1) | ZA79913B (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS56501311A (en) * | 1979-10-23 | 1981-09-17 | ||
| US4564595A (en) * | 1980-10-20 | 1986-01-14 | Biomass International Inc. | Alcohol manufacturing process |
| EP0344371A1 (en) * | 1988-05-31 | 1989-12-06 | Uop Inc. | Hydrolysis of corn kernel hulls to monosaccharides |
| DE19637909A1 (en) * | 1996-09-18 | 1998-03-19 | Infan Ingenieurgesellschaft Fu | Scrap wood processing by multistage chemical decomposition, saccharification and fermentation |
| IN2013MU03417A (en) * | 2013-10-29 | 2015-07-17 | Indian Oil Corp Ltd | |
| CN105625077A (en) * | 2016-03-27 | 2016-06-01 | 张耀忠 | Preparation method for nano-cellulose |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1641771A (en) * | 1921-03-26 | 1927-09-06 | Meiler Ludolf | Process for the production of glucose from materials containing cellulose |
| DE407412C (en) * | 1921-03-27 | 1924-12-12 | Heinrich Scholler | Process for the production of pure, isolated grape sugar from cellulosic material |
| FR851147A (en) * | 1938-03-16 | 1940-01-03 | Improvements in processes for the saccharification of cellulose, for obtaining, from woody substances, sugar solutions suitable for the production of industrial alcohol | |
| US2752270A (en) * | 1949-01-31 | 1956-06-26 | Bergin Ag Deutsche | Process of hydrolyzing wood in preparing crystalling glucose |
| FR1039819A (en) * | 1951-07-12 | 1953-10-09 | Bergin Ag Deutsche | Process for the preparation of crystallized grape sugar by hydrolysis of cellulosic substances |
| US3397198A (en) * | 1964-06-18 | 1968-08-13 | Dahlia S. Greidinger | Degraded cellulose and its manufacture |
-
1979
- 1979-02-26 ZA ZA79913A patent/ZA79913B/en unknown
- 1979-02-28 GB GB7907045A patent/GB2017710B/en not_active Expired
- 1979-02-28 AU AU44696/79A patent/AU521301B2/en not_active Ceased
- 1979-03-02 SE SE7901899A patent/SE7901899L/en not_active Application Discontinuation
- 1979-03-06 DE DE2908993A patent/DE2908993A1/en not_active Withdrawn
- 1979-03-07 JP JP2660179A patent/JPS54160801A/en active Pending
- 1979-03-07 FI FI790791A patent/FI65801C/en not_active IP Right Cessation
- 1979-03-07 BR BR7901385A patent/BR7901385A/en unknown
- 1979-03-07 MX MX176829A patent/MX151469A/en unknown
- 1979-03-08 CA CA000322981A patent/CA1119982A/en not_active Expired
- 1979-03-08 FR FR7906025A patent/FR2419351A1/en active Granted
- 1979-03-08 PH PH22268A patent/PH15122A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| DE2908993A1 (en) | 1980-01-03 |
| MX151469A (en) | 1984-11-29 |
| AU4469679A (en) | 1979-09-13 |
| FI790791A (en) | 1979-09-09 |
| FR2419351A1 (en) | 1979-10-05 |
| AU521301B2 (en) | 1982-03-25 |
| SE7901899L (en) | 1979-09-09 |
| GB2017710B (en) | 1983-02-23 |
| ZA79913B (en) | 1980-02-27 |
| BR7901385A (en) | 1979-10-02 |
| FI65801B (en) | 1984-03-30 |
| PH15122A (en) | 1982-08-10 |
| FI65801C (en) | 1984-07-10 |
| FR2419351B1 (en) | 1985-05-10 |
| GB2017710A (en) | 1979-10-10 |
| JPS54160801A (en) | 1979-12-19 |
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