Biomass composition and method for producing same

Abstract

The present invention provides a method for efficiently separating and recovering, from plant-derived biomass, a biomass composition containing, at high purity, mono- and / or poly-carboxylic acids that are highly valuable in industrial applications.　The method according to the present disclosure is a method for producing a biomass composition through steps 1 and 2-1 or steps 1 and 2-2 mentioned below, the biomass composition containing mono- and / or poly-carboxylic acids and having a total content of neutral sugar components and lignin of 70 wt% or less. Step 1: Plant-derived biomass, a solvent at least partially containing water, and a peroxide and / or a peracid are fed into a reaction system and reacted. Step 2-1: The aqueous phase is separated from the post-reaction mixture in step 1. Step 2-2: Water and / or a water-immiscible organic solvent is added to the post-reaction mixture in step 1 for liquid-liquid phase separation, and the aqueous phase is separated.

Description

Biomass composition and method for producing the same

[0001] The present disclosure relates to biomass compositions and methods for producing the same.

[0002] Cell walls of trees and herbs are mainly composed of polysaccharides, including cellulose and hemicellulose, and lignin, which is the most abundant natural aromatic polymer and has attracted attention as a renewable resource.

[0003] However, lignin is only obtained as a by-product in the pulp and paper manufacturing process and the bioethanol production process, and its utilization has not progressed to date.

[0004] For example, Patent Document 1 describes the production of dissolving pulp by subjecting lignocellulose to a hydrolysis-alkali cooking treatment to delignify it.

[0005] Furthermore, Patent Document 2 describes a method in which, by utilizing the property that cellulose dissolves more easily in ionic liquids than lignin, woody biomass is heated in an ionic liquid as a solvent, the cellulose contained in the woody biomass is dissolved in the ionic liquid while reducing its molecular weight, and the lignin is removed as a residue.

[0006] JP 2013-227705 A JP 2009-189277 A

[0007] Furthermore, most of the lignins obtained by the method described in Patent Document 1 are highly condensed and have reduced reactivity. Also, most of the lignins obtained by the method described in Patent Document 2 are modified and have reduced reactivity. Therefore, the industrial utility value of these lignins is low.

[0008] Therefore, an object of the present disclosure is to provide a method for efficiently separating and recovering a biomass composition containing highly purified mono- and / or polycarboxylic acids with high industrial utility value from plant-derived biomass. Another object of the present disclosure is to provide a biomass composition containing highly purified mono- and / or polycarboxylic acids with high industrial utility value.

[0009] As a result of intensive research to solve the above-mentioned problems, the present inventors have found that when plant-derived biomass is reacted with peroxide and / or peracid in a solvent containing at least a portion of water, lignin in the plant-derived biomass is oxidized and / or decomposed to produce water-soluble mono- and / or polycarboxylic acids with high industrial utility value. The present disclosure has been completed based on these findings.

[0010] That is, the present disclosure provides a method for producing a biomass composition, which comprises the steps of Step 1 and Step 2-1, or Step 1 and Step 2-2, and which produces a biomass composition containing mono- and / or polycarboxylic acids and having a total neutral sugar content and lignin content of 70% by weight or less, as calculated by the following method. Step 1: A reaction system is charged with plant-derived biomass, a solvent containing at least a portion of water, and a peroxide and / or peracid, and the resulting mixture is reacted. Step 2-1: An aqueous phase is separated from the reaction solution after Step 1. Step 2-2: Water and / or a water-insoluble organic solvent is added to the reaction solution after Step 1, followed by liquid separation, and the aqueous phase is separated. <Method for Measuring Neutral Sugar Content and Lignin Content> 1. 0.3 mL of 72% by weight sulfuric acid is added to 20 mg of a dried biomass composition, and the mixture is stirred at 30°C for 1 hour. 2. 8.4 mL of water is added, and the mixture is heated and decomposed in an autoclave at 120°C for 1 hour. 3. The reaction product after thermal decomposition is centrifuged to separate the supernatant and precipitate. The precipitate is regarded as lignin, washed with water, dried, and then weighed. 4. The supernatant obtained by the centrifugation is neutralized, and the centrifuged supernatant is filtered through a 0.22 μm syringe filter and analyzed by high-performance liquid chromatography to determine the neutral sugar concentration and calculate the neutral sugar content in the biomass composition.

[0011] The present disclosure also provides a method for producing the biomass composition, further comprising carrying out any one or more of the following steps 3 to 5. Step 3: Mixing the obtained aqueous phase with a water-soluble organic solvent to precipitate insoluble components. Step 4: Fractionating the obtained aqueous phase by filtering using an ultrafiltration membrane. Step 5: Adding a flocculant that interacts with carboxy groups to the obtained aqueous phase to precipitate.

[0012] The present disclosure also provides a method for producing a biomass composition, wherein the resulting biomass composition has a carboxyl group content of 1 mmol or more per gram of dry weight.

[0013] The present disclosure also provides a method for producing said biomass composition, wherein the resulting biomass composition is soluble in an aqueous solution having a pH of 2-7.

[0014] The present disclosure also provides a method for producing the biomass composition, wherein the resulting biomass composition contains nitrogen, potassium, and iron, and the total content of nitrogen, potassium, and iron in the dry matter of the biomass composition is 1000 ppm by weight or more.

[0015] The present disclosure also provides a method for producing the biomass composition, wherein the mono- and / or polycarboxylic acid is at least one compound selected from mono- and / or polycarboxylic acids having a molecular weight of 200 or less and polycarboxylic acids having a molecular weight cutoff by ultrafiltration of 3,000 or more.

[0016] The present disclosure also provides a biomass composition containing at least one compound selected from mono- or polycarboxylic acids having a molecular weight of 200 or less and polycarboxylic acids having a molecular weight cutoff of 3000 or more by ultrafiltration, wherein the total of the neutral sugar content and lignin content measured by the following method is 70% by weight or less. <Method for measuring neutral sugar content and lignin content> 1. 0.3 mL of 72% by weight sulfuric acid is added to 20 mg of dried biomass composition and stirred at 30°C for 1 hour. 2. 8.4 mL of water is added and the mixture is heated and decomposed in an autoclave at 120°C for 1 hour. 3. The reaction product after the heat decomposition is centrifuged to separate the supernatant and precipitate. The precipitate is identified as lignin, washed with water, dried, and then weighed. 4. The supernatant obtained by the centrifugation is neutralized, and the centrifuged supernatant is filtered through a 0.22 μm syringe filter and analyzed by high-performance liquid chromatography to determine the neutral sugar concentration, and the neutral sugar content in the biomass composition is calculated.

[0017] The present disclosure also provides a biomass composition having a carboxyl group content of 1 mmol or more per gram of dry weight of the biomass composition.

[0018] The present disclosure also provides the biomass composition, wherein the biomass composition is soluble in an aqueous solution having a pH of 2-7.

[0019] The present disclosure also provides a biomass composition containing nitrogen, potassium, and iron, wherein the total content of nitrogen, potassium, and iron in the dry matter of the biomass composition is 1000 ppm by weight or more.

[0020] According to the method for producing a biomass composition disclosed herein, lignin contained in plant-derived biomass in a state firmly attached to polysaccharides is oxidized and / or decomposed to form mono- and / or polycarboxylic acids, which are then separated from water-insoluble colored components and recovered in the aqueous phase. The biomass composition thus obtained is less colored and contains a large amount of mono- and / or polycarboxylic acids, making it soluble in aqueous solutions over a wide range of pH (particularly, pH 2 to 7). Therefore, the biomass composition can be used as a flocculant, dispersant, water absorbent, chelating agent, etc. It is also useful as a raw material for plastics and chemical products. The biomass composition also contains nitrogen, potassium, and iron. Therefore, it is also suitable as a soil conditioner, particularly a fertilizer.

[0021] Furthermore, by mixing alcohol with the aqueous phase, water-soluble and alcohol-insoluble components contained in the aqueous phase can be precipitated and recovered. The precipitates include sugar-derived components (e.g., glucomannan, xylan, and their oxides). By removing the precipitates, highly purified lignin-derived mono- and / or polycarboxylic acids can be recovered as water-soluble and alcohol-soluble components contained in the aqueous phase. Furthermore, by fractionating the aqueous phase through filtration using an ultrafiltration membrane, mono- and / or polycarboxylic acids can be separated into high molecular weight mono- and / or polycarboxylic acids useful as binders, etc., and low molecular weight mono- and / or polycarboxylic acids useful as basic chemicals. Furthermore, by adding a flocculant that interacts with carboxy groups to the aqueous phase, mono- and / or polycarboxylic acids can be selectively recovered.

[0022] Furthermore, if lignin is recovered from plant-derived biomass by oxidation and / or decomposition and the recovered components are further separated into mono- and / or polycarboxylic acids and sugar-derived components, a biomass composition with less coloration and more homogeneity can be obtained, and the resulting biomass composition's versatility will be further improved. Another aspect of the present invention provides water-insoluble biomass separated from the water-soluble biomass composition, and a method for producing the same.

[0023] FIG. 1 shows the results of ATR-IR measurement of the biomass composition (1), toluene phase, solid content (1), and raw material cedar wood flour obtained in Example 1. FIG. 2 shows the results of ATR-IR measurement of the 1-propanol soluble matter and 1-propanol insoluble matter (precipitate) of the biomass composition (1) obtained in Example 2, and a comparison mixture of cellulose and hemicellulose. FIG. 3 shows the results of ATR-IR measurement of the residue and filtrate obtained by MWCO 5000 separation obtained in Example 5.

[0024] [Method for Producing Biomass Composition] The method for producing a biomass composition according to the present disclosure is a method for obtaining a biomass composition containing mono- and / or polycarboxylic acids, and having a total neutral sugar content and lignin content of 70% by weight or less, calculated by the following method, through the following steps 1 and 2-1, or 1 and 2-2: Step 1: A reaction system is charged with plant-derived biomass, a solvent containing at least a portion of water, and a peroxide and / or peracid, and the mixture is reacted. Step 2-1: An aqueous phase is separated from the reaction liquid after Step 1. Step 2-2: Water and / or a water-insoluble organic solvent is added to the reaction liquid after Step 1, and the mixture is separated, and the aqueous phase is separated.

[0025] The neutral sugar content and lignin content are measured by the Klason method described below. <Method for measuring neutral sugar content and lignin content> 1. 0.3 mL of 72 wt % sulfuric acid is added to 20 mg of dried biomass composition and stirred at 30°C for 1 hour. 2. 8.4 mL of water is added and thermal decomposition is carried out at 120°C for 1 hour using an autoclave. 3. The reaction product after thermal decomposition is centrifuged to separate the supernatant and precipitate. The precipitate is taken as lignin and is washed with water, dried, and then weighed. 4. The supernatant obtained from the centrifugation is neutralized, and the centrifuged supernatant is filtered through a 0.22 μm syringe filter and analyzed by high-performance liquid chromatography to determine the neutral sugar concentration and calculate the neutral sugar content in the biomass composition.

[0026] (Step 1) Step 1 is a step of charging plant-derived biomass, a solvent containing at least a portion of water, and a peroxide and / or peracid into a reaction system and reacting them. This step enables the plant-derived biomass to be delignified, and the lignin separated from the plant-derived biomass can be extracted into the solvent as oxides and / or decomposition products.

[0027] The reaction of the plant-derived biomass with the peroxide and / or peracid may be carried out in the presence of an ionic liquid and / or an acid catalyst, which enhances the delignification effect of the peroxide or peracid.

[0028] (Plant-derived biomass) Plant-derived biomass includes woody biomass including woody plants and processed products thereof, and herbaceous biomass including herbaceous plants and processed products thereof.

[0029] The plant-derived biomass contains a lignin-polysaccharide complex, which is preferably a structure in which lignin and cellulose are bonded, i.e., lignocellulose.

[0030] The polysaccharides that make up the lignin-polysaccharide complex are preferably cell wall polysaccharides that mainly contain cellulose and hemicellulose.

[0031] Cellulose is a polysaccharide that forms the backbone of plant cell walls and is composed of [CH 10In plant cell walls, several dozen cellulose molecules are bundled together to form microfibrils, and multiple microfibrils then associate in a rope-like fashion to form microfibrils.

[0032] The cellulose content in the plant-derived biomass varies depending on the type of plant used as the raw material for the polysaccharides. When wood is used as the raw material, the cellulose content is approximately 50% by weight. When cotton fiber is used as the raw material, the cellulose content is, for example, 88 to 96% by weight.

[0033] Hemicellulose is a general term for polysaccharides other than cellulose that exist between cellulose microfibrils. Hemicellulose is composed of monosaccharides such as xylose, arabinose, mannose, and galactose, and has the effect of strengthening the cell wall by linking cellulose microfibrils to form a mesh structure.

[0034] Lignin is a polymeric compound in which a three-dimensional network structure is formed by the high degree of polymerization of phenolic compounds (for example, sinapyl alcohol, coniferyl alcohol, p-coumaryl alcohol, etc.).

[0035] Specific examples of plant-derived biomass that can be used include cut or crushed materials (e.g., chips, sawdust, etc.) of at least one plant selected from wood (conifers such as cedar, broad-leaved trees such as eucalyptus, etc.), seed hairs (cotton linters, bombax cotton, kapok, etc.), gin bark (e.g., hemp, mulberry, mitsumata, etc.), and leaves (e.g., Manila hemp, New Zealand hemp, etc.). Furthermore, processed plant-derived biomass, such as waste paper, used clothing, and lignin obtained as a by-product in conventional pulping, can also be used as raw materials.

[0036] (Solvent) The delignification reaction is carried out in a solvent. The solvent contains at least a portion of water. The solvent may contain, together with water, at least one solvent selected from a water-soluble organic solvent and a water-insoluble organic solvent.

[0037] The proportion of water in the total amount of the solvent is, for example, 1% by weight or more, preferably 5% by weight or more, more preferably 10% by weight or more, more preferably 20% by weight or more, and may further be 30% by weight or more, or 40% by weight or more.

[0038] The proportion of the total content of water and the water-soluble organic solvent in the total amount of the solvent is, for example, 1% by weight or more, preferably 5% by weight or more, more preferably 10% by weight or more, more preferably 20% by weight or more, and may further be 30% by weight or more, or 40% by weight or more.

[0039] The proportion of the water-insoluble organic solvent in the total amount of the solvent is, for example, 99% by weight or less, preferably 95% by weight or less, more preferably 90% by weight or less, more preferably 80% by weight or less, and may further be 70% by weight or less, or 60% by weight or less.

[0040] The water used as the solvent may be water contained in plant-derived biomass, or may be water that dissolves peroxides or peracids.

[0041] The water-soluble organic solvent may, for example, be a carboxylic acid.

[0042] Examples of the carboxylic acid include aliphatic monocarboxylic acids such as acetic acid, propionic acid, lactic acid, glycolic acid, and glyoxylic acid; aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, maleic acid, glutamic acid, and malic acid; aliphatic polycarboxylic acids such as citric acid, 1,2,3,4-cyclobutanetetracarboxylic acid, and 1,2,4,5-cyclohexanetetracarboxylic acid; aromatic monocarboxylic acids such as benzoic acid, 2-chlorobenzoic acid, 4-(chloromethyl)benzoic acid, salicylic acid, 1-naphthoic acid, and diphenylacetic acid; aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, and terephthalic acid; and aromatic polycarboxylic acids such as trimesic acid. These may be used alone or in combination of two or more.

[0043] Examples of non-water-soluble organic solvents include hydrocarbon solvents such as pentane, hexane, cyclohexane, heptane, and octane; aromatic hydrocarbon solvents such as benzene, toluene, and xylene; halogenated hydrocarbon solvents such as carbon tetrachloride, trichloroethylene, chloroform, 1,1,1-trichloroethane, methylene dichloride, ethylene dichloride, monochlorobenzene, and chloronaphthalene; and ester solvents such as butyl acetate and ethyl acetate. These can be used alone or in combination of two or more.

[0044] The use of a water-insoluble organic solvent allows the elution of difficult-to-decompose components, such as lignans, terpenes, and lignin, contained in plant-derived biomass, as well as decomposition products of these components, such as aromatic carboxylic acids, aromatic hydroxy acids, aromatic polyols, methoxyphenols, carboxylic acid esters, guaiacol, or peroxides of these compounds, into the water-insoluble organic solvent, thereby enabling the production of a biomass composition containing highly purified mono- and / or polycarboxylic acids in the aqueous phase. Note that either the water-insoluble organic solvent eluate or the aqueous phase compounds have also been detected when a lignin model substance (e.g., a dimer) was treated using the production method of the present invention.

[0045] The aqueous phase may contain, for example, hydroxy acids, polyols, phenols, and the like.

[0046] The amount of solvent used (the total amount when two or more types are used) can be appropriately selected taking into consideration operability, reaction rate, etc., and is, for example, 1 to 50 mL, preferably 3 to 20 mL, per 1 g (dry weight) of plant-derived biomass.

[0047] (Peroxide and / or Peracid) Peroxides and peracids have a delignification effect (i.e., the effect of oxidizing and / or decomposing lignin that forms a complex with polysaccharides in plant-derived biomass, thereby releasing it from the complex).

[0048] The peroxide may be a compound represented by the following formula (a): 11 -O-O-R 12 (a) (wherein, R 11 , R12 are the same or different and represent a hydrogen atom, a monovalent hydrocarbon group, or an acyl group (RCO group; R is a monovalent hydrocarbon group).

[0049] The monovalent hydrocarbon group includes a monovalent aliphatic hydrocarbon group, a monovalent alicyclic hydrocarbon group, a monovalent aromatic hydrocarbon group, and a monovalent group formed by combining these groups.

[0050] Of the monovalent hydrocarbon groups, monovalent aliphatic hydrocarbon groups, monovalent aromatic hydrocarbon groups, and monovalent groups in which two or more of the above groups are bonded are preferred.

[0051] The monovalent aliphatic hydrocarbon group is preferably an aliphatic hydrocarbon group having 1 to 20 carbon atoms, and particularly preferably a linear or branched alkyl group having 1 to 20 carbon atoms (preferably 1 to 10, and particularly preferably 1 to 5).

[0052] The monovalent aromatic hydrocarbon group is preferably an aryl group having 6 to 14 carbon atoms (preferably 6 to 10 carbon atoms), such as a phenyl group or a naphthyl group.

[0053] As the monovalent group formed by bonding two or more groups selected from monovalent aliphatic hydrocarbon groups and monovalent aromatic hydrocarbon groups, an aralkyl group having 7 to 10 carbon atoms, such as a benzyl group, is preferred.

[0054] The peroxide may be, for example, hydrogen peroxide (a compound represented by formula (a), where R 11 , R 12 represents a hydrogen atom); hydroperoxides such as t-butyl hydroperoxide and benzyl hydroperoxide (compounds represented by formula (a), 11 represents a monovalent hydrocarbon group, and R 12 represents a hydrogen atom); peroxides such as di-t-butyl peroxide and benzoyl peroxide (compounds represented by formula (a), 11 , R 12 and the like may be the same or different and each represents a monovalent hydrocarbon group or an acyl group).

[0055] Examples of the peracid include organic peracids such as percarboxylic acids (e.g., performic acid, peracetic acid, trifluoroperacetic acid, perbenzoic acid, metachloroperbenzoic acid, monoperoxyphthalic acid, etc.); and inorganic peracids such as permanganic acid. These may be used alone or in combination of two or more.

[0056] The amount of peroxide or peracid used (the total amount when a peroxide and a peracid are used in combination) is, for example, 1 equivalent or more, preferably 3 equivalents or more, more preferably 5 equivalents or more, and particularly preferably 10 equivalents or more per monomer unit of lignin contained in plant-derived biomass. The upper limit of the amount of peroxide or peracid used is, for example, 30 equivalents, preferably 20 equivalents.

[0057] The amount of peroxide or peracid used (or the total amount when a peroxide and a peracid are used in combination) can be varied depending on the amount of lignin contained in the plant-derived biomass, but is, for example, 0.2 to 5.0 mmol, preferably 0.5 to 5.0 mmol, particularly preferably 0.7 to 4.0 mmol, and most preferably 1.0 to 3.0 mmol per 100 mg of plant-derived biomass. When the amount of peroxide or peracid used is within the above range, the oxidation and / or decomposition reaction of lignin in the plant-derived biomass proceeds rapidly, and the delignification reaction of the plant-derived biomass proceeds, resulting in the production of polysaccharides with an extremely low residual lignin. Furthermore, by suppressing excessive decomposition, polysaccharides with an appropriate molecular weight can be obtained.

[0058] (Ionic Liquid) Ionic liquids react with peroxides or peracids to generate peroxides derived from the ionic liquid. The generated peroxides derived from the ionic liquid have the effect of promoting the progress of the delignification reaction. Furthermore, oxides and / or decomposition products of lignin generated by the delignification reaction are released from the plant-derived biomass and dissolve in water. Therefore, the ionic liquid has the effect of acting as a dissolution promoter, promoting the dissolution of lignin in water.

[0059] An ionic liquid is a salt that is composed of cations and anions and is liquid at room temperature (25° C.).

[0060] Examples of cations constituting the ionic liquid include organic nitrogen-based cations such as imidazolium cation, pyridinium cation, pyrrolidinium cation, and ammonium cation; organic phosphorus-based cations such as phosphonium cation; and organic sulfur-based cations such as sulfonium cation.

[0061] Examples of anions constituting an ionic liquid include halide ions (e.g., Cl - ,Br - , I - ), RfOSO3 - ,p-CH3C6H4SO3 - (tosylate), RfSO3 - , (RfSO2)2N - , BF4 - , PF6 - , (RfSO2)3C - , (CN)2N - , (RfO)2PO2 - The Rf represents a halogenated alkyl group having 1 to 12 carbon atoms.

[0062] Of these, imidazolium salts are preferred as ionic liquids because they have a particularly excellent delignification effect.

[0063] The imidazolium salt is represented, for example, by the following formula (b-1): In the present disclosure, the imidazolium salt also includes a compound represented by the following formula (b-2): (In the above formula (b-1), R 1 , R 3 are the same or different and represent a monovalent hydrocarbon group; R 2 , R 4 , R 5 are the same or different and represent a hydrogen atom or a monovalent hydrocarbon group. - represents a counter anion) (In the above formula (b-2), R 1 represents a monovalent hydrocarbon group, and R 2 , R 4 , R 5 are the same or different and represent a hydrogen atom or a monovalent hydrocarbon group. 6 represents a divalent hydrocarbon group. - indicates an anionic group)

[0064] The monovalent hydrocarbon group includes a monovalent aliphatic hydrocarbon group, a monovalent alicyclic hydrocarbon group, a monovalent aromatic hydrocarbon group, and a monovalent group formed by combining these groups. The monovalent hydrocarbon group may have a substituent, and examples of the substituent include a carboxy group (-COOH), a sulfonic acid group (-SO3H), a phosphate group (H2PO4 - ) etc.

[0065] The monovalent aliphatic hydrocarbon group is preferably an aliphatic hydrocarbon group having 1 to 20 carbon atoms. Examples include linear or branched alkyl groups having about 1 to 20 carbon atoms (preferably 1 to 10, particularly preferably 1 to 5), such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, s-butyl, t-butyl, pentyl, hexyl, decyl, and dodecyl; linear or branched alkenyl groups having about 2 to 20 carbon atoms (preferably 2 to 10, particularly preferably 2 to 3), such as vinyl, allyl, and 1-butenyl; and linear or branched alkynyl groups having about 2 to 20 carbon atoms (preferably 2 to 10, particularly preferably 2 to 3), such as ethynyl and propynyl.

[0066] The monovalent alicyclic hydrocarbon group includes C 3-20 Alicyclic hydrocarbon groups are preferred, and examples thereof include cycloalkyl groups having about 3 to 20 members (preferably 3 to 15 members, particularly preferably 5 to 8 members) such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and cyclooctyl groups; cycloalkenyl groups having about 3 to 20 members (preferably 3 to 15 members, particularly preferably 5 to 8 members) such as cyclopentenyl and cyclohexenyl groups; perhydronaphthalen-1-yl groups, norbornyl groups, adamantyl groups, tricyclo[5.2.1.0] groups, and the like. 2,6 ] decan-8-yl group, tetracyclo[4.4.0.1 2,5 .1 7,10 ] Bridged cyclic hydrocarbon groups such as dodecan-3-yl group and the like can be given.

[0067] The monovalent aromatic hydrocarbon group includes C 6-14 (Especially C 6-10 ) An aryl group is preferred, and examples thereof include a phenyl group and a naphthyl group.

[0068] Of the monovalent hydrocarbon groups, monovalent aliphatic hydrocarbon groups are preferred, and linear or branched alkyl groups or linear or branched alkenyl groups are particularly preferred.

[0069] The divalent hydrocarbon group includes groups in which one hydrogen atom has been removed from the structural formula of the monovalent hydrocarbon group described above.

[0070] Of the divalent hydrocarbon groups, divalent aliphatic hydrocarbon groups are preferred, and linear or branched alkylene groups or linear or branched alkenylene groups are particularly preferred.

[0071] X - As the counter anion in the above, the same examples as the anions constituting the ionic liquid can be mentioned.

[0072] Y - The anionic group in the formula (I) is, for example, —COO - group, -SO3 - group, -HPO4 - group, -PO4 2- groups, etc.

[0073] Among the imidazolium salts, a compound represented by formula (b-1) is particularly preferred, wherein R 1 represents an alkyl group having 1 to 10 carbon atoms, and R 3 represents a hydrocarbon group (preferably an alkyl group having 1 to 10 carbon atoms) having a sulfonic acid group as a substituent, and R 2 , R 4 , R 5 represents a hydrogen atom, and X - is p-CH3C6H4SO3 - and / or a compound represented by formula (b-2), wherein Y - Ga-SO3 - Compounds which are groups are particularly preferred because they are excellent in the effect of accelerating the progress of the delignification reaction.

[0074] The amount of ionic liquid used (the total amount when two or more types of ionic liquids are used) (B) is, for example, 1 to 100 μmol, preferably 5 to 100 μmol, particularly preferably 10 to 50 μmmol, and most preferably 20 to 40 μmol per 100 mg of plant-derived biomass.

[0075] When the ionic liquid is used in the above range, the progress of the delignification reaction can be promoted, and polysaccharides with a low lignin content can be produced efficiently.

[0076] (Acid catalyst) The acid catalyst preferably reacts with a peroxide or peracid to generate a peroxide derived from the acid catalyst. The generated peroxide derived from the acid catalyst exhibits the effect of promoting the progress of the delignification reaction. Furthermore, the oxides and / or decomposition products of lignin generated by the delignification reaction are released from the plant-derived biomass and dissolve in water and / or an organic solvent. Therefore, the acid catalyst has the effect of acting as a dissolution promoter, promoting the dissolution of lignin in water and / or an organic solvent.

[0077] The acid catalyst may be an inorganic acid or an organic acid, and these may be used alone or in combination of two or more.

[0078] Examples of the inorganic acid include sulfuric acid, hydrochloric acid, nitric acid, and phosphoric acid.

[0079] Examples of the organic acid include carboxylic acid, sulfonic acid, phosphonic acid, and phosphinic acid. The organic acid may be a hydrate. When the organic acid has a plurality of acid groups, some of the acid groups may form salts. An organic acid in which some of the acid groups form salts may be liquid at room temperature (25°C). That is, the organic acid may be an ionic liquid.

[0080] Examples of the salts that may be formed by the organic acids include alkali metal salts such as sodium salts and potassium salts; alkaline earth metal salts such as calcium salts and magnesium salts; and amine salts such as imidazole salts and pyridine salts.

[0081] The carboxylic acid is a compound having at least one carboxy group, and examples thereof include monocarboxylic acids such as formic acid, acetic acid, succinic acid, lactic acid, glycolic acid, and glyoxylic acid; and polycarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutamic acid, maleic acid, humic acid, phthalic acids, citric acid, and malic acid.

[0082] The carboxylic acid is preferably a monocarboxylic acid. The carboxylic acid is preferably an aliphatic carboxylic acid. The carboxylic acid is particularly preferably an aliphatic monocarboxylic acid such as glyoxylic acid.

[0083] The sulfonic acid is a compound having at least one sulfonic acid group (SO3H group), and is represented, for example, by the following formula (c): R-(SO3H) n (c) (wherein R represents an n-valent hydrocarbon group or an n-valent heterocyclic group, and n represents an integer of 1 or more)

[0084] Among the n-valent hydrocarbon groups in R, the monovalent hydrocarbon group is 1 Examples of the n-valent hydrocarbon group, where n is an integer of 2 or greater, include groups in which n-1 hydrogen atoms have been removed from the structural formula of the monovalent hydrocarbon group.

[0085] The heterocycle constituting the n-valent heterocyclic group in R includes aromatic heterocycles and non-aromatic heterocycles. Examples of the heterocycle include 3- to 10-membered rings (preferably 4- to 6-membered rings) containing carbon atoms and at least one heteroatom (e.g., oxygen atom, sulfur atom, nitrogen atom, phosphorus atom, etc.) as ring-constituting atoms. The heterocycle may be condensed with a 3- to 8-membered cycloalkane ring.

[0086] As the sulfonic acid, an aromatic sulfonic acid represented by the following formula (c-1) is preferred because it has an excellent effect of accelerating the delignification reaction. (In the above formula, ring Z represents an aromatic hydrocarbon ring or an aromatic heterocyclic ring, and R 2 represents a divalent hydrocarbon group; m represents an integer of 0 or more; and n represents an integer of 1 or more.

[0087] Examples of the aromatic hydrocarbon ring in the ring Z include aromatic hydrocarbon rings having 6 to 14 carbon atoms, such as a benzene ring, a naphthalene ring, and an anthracene ring. A 3- to 8-membered cycloalkane ring may be condensed with the aromatic hydrocarbon ring.

[0088] Examples of the aromatic heterocycle for ring Z include a 3- to 10-membered (preferably 4- to 6-membered) aromatic heterocycle having at least one heteroatom, and a fused ring formed by fusing a 3- to 8-membered cycloalkane ring to the aromatic heterocycle. Specific examples include pyrrole, furan, thiophene, phosphole, pyrazole, imidazole, oxazole, isoxazole, thiazole, indole, benzofuran, benzothiophene, isoindole, isobenzofuran, benzophosphole, benzimidazole, benzoxazole, benzothiazole, benzisoxazole, indazole, benzisothiazole, benzotriazole, purine, pyridine, phosphinine, pyrimidine, pyrazine, pyridazine, triazine, 1,2,4,5-tetrazine, 1,2,3,4-tetrazine, 1,2,3,5-tetrazine, hexazine, quinoline, isoquinoline, quinoxaline, quinazoline, cinnoline, pteridine, phthalazine, acridine, 4aH-phenoxazine, and carbazole.

[0089] The R 2 The divalent hydrocarbon group in is preferably a divalent (saturated) aliphatic hydrocarbon group, particularly preferably an alkylene group having 1 to 10 carbon atoms, and most preferably an alkylene group having 1 to 7 carbon atoms.

[0090] Examples of the compound in which ring Z in formula (c-1) is an aromatic hydrocarbon ring include benzenesulfonic acid; toluenesulfonic acids such as p-toluenesulfonic acid; and naphthalenesulfonic acids such as 1-naphthalenesulfonic acid, 2-naphthalenesulfonic acid, 1,5-naphthalenedisulfonic acid, and 2-naphthylmethanesulfonic acid.

[0091] Examples of the compound in which ring Z in formula (c-1) is an aromatic heterocycle include compounds represented by the following formula (c-1-3), such as 1-methyl-3-(3-sulfopropyl)imidazolium p-toluenesulfonate; and 2-(3-(2-sulfoethyl)-1H-imidazol-1-yl)ethanesulfonate.

[0092] Examples of the phosphonic acids include aliphatic phosphonic acids such as methylphosphonic acid; and aromatic phosphonic acids such as phenylphosphonic acid.

[0093] Examples of the phosphinic acid include aliphatic phosphinic acids such as dimethylphosphinic acid; and aromatic phosphinic acids such as diphenylphosphinic acid.

[0094] Of these, the acid catalyst is preferably a carboxylic acid, a sulfonic acid, or sulfuric acid, more preferably a sulfonic acid or sulfuric acid, particularly preferably a sulfonic acid, and most preferably an aromatic sulfonic acid.

[0095] The amount of acid catalyst used (the total amount when two or more types of acid catalysts are used) (C) can be changed appropriately depending on the type of acid catalyst, but is, for example, 0.01 to 10 mmol, preferably 0.05 to 5 mmol, and particularly preferably 0.1 to 3 mmol per 1 g (dry weight) of plant-derived biomass.

[0096] The amount of carboxylic acid used as the acid catalyst is, for example, 0.1 to 10 mmol, preferably 0.2 to 8 mmol, and particularly preferably 0.3 to 6 mmol, per 1 g (dry weight) of plant-derived biomass.

[0097] The amount of sulfonic acid or sulfuric acid used as the acid catalyst is, for example, 0.01 to 1 mmol, preferably 0.05 to 0.7 mmol, particularly preferably 0.1 to 0.5 mmol, and most preferably 0.15 to 0.4 mmol per 1 g (dry weight) of plant-derived biomass.

[0098] When the acid catalyst is used in the above range, the progress of the delignification reaction can be promoted, and mono- and / or polycarboxylic acids can be recovered efficiently.

[0099] The molar ratio (A / C) of the amount (A) of peroxide and peracid used to the amount (C) of acid catalyst used is, for example, 1 to 400, and the upper limit of the molar ratio is preferably 300, more preferably 2000, and particularly preferably 100. The lower limit of the molar ratio is preferably 10, more preferably 30, particularly preferably 50, and most preferably 70. When the molar ratio is within the above range, the effect of promoting the progress of the delignification reaction can be obtained. Note that the amount (A) used is the total amount of peroxide and peracid used, and the amount of either the peroxide or the peracid used may be zero.

[0100] (Reaction Conditions for Step 1) The reaction atmosphere for step 1 is not particularly limited as long as it does not inhibit the reaction, and may be, for example, any of an air atmosphere, a nitrogen atmosphere, an argon atmosphere, and the like.

[0101] The reaction in step 1 may be carried out under normal pressure, reduced pressure, or increased pressure. In the method of the present disclosure, since a peroxide and / or a peracid is used, the reaction can proceed efficiently even when carried out under normal pressure (for example, under an atmosphere of 0.5 to 5.0 atm).

[0102] The reaction temperature in step 1 is, for example, 120°C or lower, preferably 100°C or lower, more preferably 90°C or lower, even more preferably 85°C or lower, and particularly preferably 80°C or lower. The lower limit of the reaction temperature is, for example, 20°C, preferably 55°C, and particularly preferably 60°C. The reaction time is, for example, 0.5 to 48 hours, preferably 1 to 24 hours, and particularly preferably 2 to 8 hours. The reaction can be carried out by any method, such as a batch method, a semi-batch method, or a continuous method.

[0103] When plant-derived biomass is subjected to the reaction in step 1, lignin constituting the plant-derived biomass is oxidized and / or decomposed to produce mono- and / or polycarboxylic acids. The mono- and / or polycarboxylic acids thus produced are separated from polysaccharides and dissolved in a solvent without condensation.

[0104] The polysaccharide is, for example, a cellulose fiber, and contains at least one monosaccharide selected from glucose, xylose, and mannose as a constituent component.

[0105] (Step 2-1) Step 2-1 is a step of separating and collecting the aqueous phase from the reaction solution after step 1.

[0106] The aqueous phase contains water, a water-soluble organic solvent (when a water-soluble organic solvent is used as the solvent, the water-soluble organic solvent is also included in the aqueous phase), and components that are soluble in these solvents.

[0107] The method for carrying out step 2-1 can be selected depending on the composition of the reaction solution after step 1. When the reaction solution after step 1 is capable of being distinguished into an aqueous phase and a water-insoluble organic solvent, step 2-1 can be carried out, for example, by method 1 selected from the following methods. - The aqueous phase or the water-insoluble organic solvent is removed by direct decantation or with a pipette, and the aqueous phase is separated. - The reaction solution after step 1 is filtered, and the obtained filtrate is mixed and allowed to stand to separate into an aqueous phase and a water-insoluble organic solvent phase, and then the aqueous phase or the water-insoluble organic solvent is removed, and the aqueous phase is separated.

[0108] When the reaction solution after step 1 contains only an aqueous phase, the reaction solution after step 1 can be filtered to separate it from the solid phase and collect the aqueous phase.

[0109] (Step 2-2) Step 2-2 is a step in which water and / or a water-insoluble organic solvent is added to the reaction solution after step 1, followed by separation, and the aqueous phase is separated.

[0110] Step 2-2 can be carried out, for example, by one of the following methods. For example, when the reaction solution after step 1 contains extremely little water or a water-insoluble organic solvent, or when the reaction solution is absorbed into the solid phase and the aqueous phase cannot be distinguished, the following method can be selected: Water and / or a water-insoluble organic solvent is added, followed by stirring and standing to separate the mixture into a water-insoluble organic solvent phase, an aqueous phase, and a solid phase. The upper phase (often the water-insoluble organic solvent phase) is removed by decantation or a pipette, and the solid phase is then removed by filtration or the like, and the aqueous phase is separated. The solid phase removed by the above method may be washed with a water-insoluble organic solvent or a solvent in which the components contained in the aqueous phase have low solubility, followed by adding water to extract the aqueous phase components contained in the solid phase, which may then be added to the aqueous phase. The reaction solution after step 1 is filtered, and the filtrate is washed with a water-insoluble organic solvent or a solvent in which the aqueous phase components have low solubility, followed by adding water to extract the aqueous phase components contained in the filtrate. The reaction solution after step 1 is filtered, and water and / or a water-insoluble organic solvent is added to the filtrate and mixed, and the water-insoluble organic solvent phase and the aqueous phase are separated.

[0111] When the reaction solution after step 1 is water only or a mixture of water and a water-soluble organic solvent, the reaction can be carried out by, for example, one method selected from the following methods. A water-insoluble organic solvent is added to the reaction solution after step 1 (to extract low-water-soluble components into the water-insoluble organic solvent), the reaction solution is separated into a water-insoluble organic solvent phase, an aqueous phase, and a solid phase, and the aqueous phase is separated. The solid phase obtained by the above method may be washed with a water-insoluble organic solvent or a solvent in which the components contained in the aqueous phase are poorly soluble, followed by addition of water to extract the aqueous phase components contained in the solid phase, which is then added to the aqueous phase. The reaction solution after step 1 is filtered, and a water-insoluble organic solvent is added to the filtrate (to extract low-water-soluble components into the water-insoluble organic solvent), the reaction solution is separated into a water-insoluble organic solvent phase and an aqueous phase, and the aqueous phase is separated. The filtrate obtained by the filtration may be washed with a water-insoluble organic solvent or a solvent in which the components contained in the aqueous phase are poorly soluble, followed by addition of water to extract the aqueous phase components contained in the filtrate, which is then added to the aqueous phase.

[0112] Examples of the non-water-soluble organic solvent include the same examples as the non-water-soluble organic solvent that can be used as the solvent.

[0113] The amount of water and / or water-insoluble organic solvent added is, for example, 0.1 to 10 mL, preferably 0.3 to 5 mL, and more preferably 0.5 to 3 mL per 100 mg of plant-derived biomass.

[0114] The biomass composition obtained through Step 2-1 or 2-2 has little coloration and contains a large amount of mono- and / or polycarboxylic acids. The carboxyl group content per gram of dry weight of the obtained biomass composition is, for example, 1 mmol or more, preferably 1.5 mmol or more, more preferably 2.0 mmol or more, particularly preferably 3.0 mmol or more, and most preferably 5.0 mmol or more. The upper limit of the carboxyl group content is, for example, 20 mmol.

[0115] The mono- and / or polycarboxylic acids include low-molecular-weight mono- and / or polycarboxylic acids having a molecular weight of 200 or less (e.g., a molecular weight of 46 to 200) and high-molecular-weight polycarboxylic acids having an ultrafiltration molecular weight cutoff of 3000 or more. Fractionation by ultrafiltration can also be carried out with molecular weights of, for example, 1000, 5000, 10000, or 50000.

[0116] The biomass composition is soluble in aqueous solutions with a wide range of pH, from 2 to 14. Furthermore, since the biomass composition contains a large amount of mono- and / or polycarboxylic acids, it is soluble in aqueous solutions with a pH of from 2 to 7 (preferably from 2 to 5, and particularly preferably from 2 to 4). At room temperature and normal pressure (25°C, 1 atmosphere), the dry weight of the biomass composition that dissolves in 100 mL of an aqueous solution with a pH of from 2 to 7 is, for example, 0.5 g or more, preferably 5 g or more, and particularly preferably 30 g or more.

[0117] Furthermore, in the dried biomass composition, the total content of neutral sugar components and lignin determined by the above method is 70% by weight or less, preferably 50% by weight or less, more preferably 45% by weight or less, even more preferably 40% by weight or less, particularly preferably 30% by weight or less, and most preferably 20% by weight or less.

[0118] The lignin content in the dry matter of the biomass composition is 10% by weight or less, preferably 8% by weight or less, more preferably 5% by weight or less, particularly preferably 3% by weight or less, and most preferably 1% by weight or less.

[0119] The biomass composition also contains nitrogen, potassium, and iron. The total content (element equivalent) of nitrogen, potassium, and iron in the dry matter of the biomass composition is 1,000 ppm by weight or more, preferably 3,000 ppm by weight or more, particularly preferably 5,000 ppm by weight or more, and most preferably 6,000 ppm by weight or more. The upper limit of the total content is, for example, 50,000 ppm by weight. Therefore, the biomass composition is useful as a soil conditioner or fertilizer.

[0120] The potassium content (element equivalent) in the dry matter of the biomass composition is 500 ppm by weight or more, preferably 1000 ppm by weight or more, particularly preferably 3000 ppm by weight or more, and most preferably 5000 ppm by weight or more. The upper limit of the total content is, for example, 30000 ppm by weight.

[0121] The nitrogen content (element equivalent) in the dry matter of the biomass composition is 100 ppm by weight or more, preferably 300 ppm by weight or more, particularly preferably 600 ppm by weight or more, and most preferably 1000 ppm by weight or more. The upper limit of the total content is, for example, 30000 ppm by weight.

[0122] The iron content (element equivalent) in the dry matter of the biomass composition is 10 ppm by weight or more, preferably 30 ppm by weight or more, and particularly preferably 50 ppm by weight or more. The upper limit of the total content is, for example, 2000 ppm by weight.

[0123] The biomass composition has a low phosphorus content, and the phosphorus content (element equivalent) in the dry matter of the biomass composition is 5 ppm by weight or less, preferably 3 ppm by weight or less, and particularly preferably 1 ppm by weight or less. The lower limit of the total content is, for example, 0.01 ppm by weight.

[0124] The biomass composition may be further subjected to one or more of the following steps 3 to 5, as needed. Step 3: A water-soluble organic solvent is mixed with the obtained aqueous phase to precipitate insoluble components. Step 4: The obtained aqueous phase is subjected to a filtration treatment using an ultrafiltration membrane to fractionate it. Step 5: A flocculant that interacts with carboxy groups is added to the obtained aqueous phase to precipitate it. (Step 3) Step 3 is a step in which the aqueous phase obtained in step 2-1 or 2-2 is mixed with a water-soluble organic solvent to precipitate insoluble components.

[0125] Examples of the water-soluble organic solvent include alcohols, ketones, ethers, etc. These may be used alone or in combination of two or more.

[0126] Examples of the alcohol include methanol, ethanol, propanol, butanol, etc. Among these, propanol or butanol is preferred, and propanol (for example, 1-propanol) is particularly preferred.

[0127] Examples of the ketone include acetone and methyl ethyl ketone.

[0128] Examples of the ether include tetrahydrofuran, dioxane, and 1,2-dimethoxyethane.

[0129] The amount of the water-soluble organic solvent used is, for example, 0.1 to 50 mL, preferably 0.5 to 5 mL, per 100 mg of plant-derived biomass.

[0130] Furthermore, by mixing the aqueous phase with a water-soluble organic solvent, components contained in the aqueous phase that are soluble in water but insoluble in the water-soluble organic solvent can be precipitated and recovered.

[0131] The precipitates include sugar-derived components (e.g., glucomannan, xylan, and oxides thereof), etc. The sugar-derived components are useful as food additives, feed, basic chemical raw materials, etc.

[0132] Then, by removing the precipitate, it is possible to recover a highly purified mono- and / or polycarboxylic acid as a component contained in the aqueous phase, which is soluble in water and also in a water-soluble organic solvent. The highly purified mono- and / or polycarboxylic acid can be used as a binder, a flocculant, a dispersant, a water absorbent, a chelating agent, etc., and is also useful as a raw material for plastics and chemical products.

[0133] (Step 4) Step 4 is a step in which the aqueous phase obtained in step 2-1 or 2-2 is fractionated by filtering using an ultrafiltration membrane.

[0134] When an ultrafiltration membrane with a molecular weight cutoff (MWCO) of, for example, 1,000 to 10,000 is used, a high molecular weight polycarboxylic acid is obtained as the filtrate. High molecular weight polycarboxylic acids are useful as binders, flocculants / dispersants, water absorbents, and chelating agents. In addition, low molecular weight mono- and / or polycarboxylic acids are obtained as the filtrate. Low molecular weight mono- and / or polycarboxylic acids are useful as basic chemicals.

[0135] (Step 5) Step 5 is a step of adding a flocculant that interacts with carboxy groups to the aqueous phase obtained in step 2-1 or 2-2 to cause precipitation.

[0136] The flocculant includes inorganic flocculants and organic flocculants, and one flocculant may be used alone or two or more flocculants may be used in combination.

[0137] Examples of inorganic flocculants include iron-based flocculants such as iron oxide, iron chloride, iron nitrate, iron sulfate (such as polyferric sulfate), aluminum sulfate, polyaluminum chloride, and calcium hydroxide, as well as aluminum-based flocculants and calcium-based flocculants.

[0138] Examples of organic flocculants include cationic, nonionic, and anionic polymer flocculants.

[0139] Since the aqueous phase obtained in step 2-1 or 2-2 is acidic, a flocculant that is effective under acidic conditions may be used, or the pH of the aqueous phase obtained in step 2-1 or 2-2 may be adjusted before adding the flocculant. In the biomass composition of the present invention, a flocculant can be appropriately selected and used depending on the application. For example, when the biomass composition is used as a fertilizer, a flocculant containing a nutrient element (e.g., a flocculant containing K, N, Fe, or P) can be used.

[0140] The amount of the flocculant used is, for example, 0.001 to 20 mg per 100 mg of plant-derived biomass.

[0141] When the flocculant is added to the aqueous phase obtained in step 2-1 or 2-2, the mono- and / or polycarboxylic acid interacts with the flocculant and precipitates, and high-purity mono- and / or polycarboxylic acid can be easily recovered by removing the water. The high-purity mono- and / or polycarboxylic acid can be used as a binder, flocculant, dispersant, water absorbent, chelating agent, etc. It is also useful as a raw material for plastics and chemical products.

[0142] The above-described configurations and combinations thereof of the present disclosure are merely examples, and additions, omissions, substitutions, and modifications of the configurations are possible as appropriate within the scope of the present disclosure. Furthermore, the present disclosure is not limited to the embodiments, but is limited only by the claims.

[0143] The present disclosure will be explained in more detail below using examples, but the present disclosure is not limited to these examples.

[0144] Example 1: 10 g of cedar wood flour (10 wt. % moisture content) milled using a Willey mill (1000 μm pass), 2.6 mmol of p-toluenesulfonic acid monohydrate (Fujifilm Wako Pure Chemical Industries, Ltd.) as a catalyst, 20 mL of 30% hydrogen peroxide solution (Fujifilm Wako Pure Chemical Industries, Ltd.), and 40 mL of toluene (Fujifilm Wako Pure Chemical Industries, Ltd.) as a solvent were placed in an eggplant flask and stirred at 60°C for 24 hours to obtain a reaction solution. After cooling, 100 mL of water was added, and the contents were stirred and mixed, then allowed to stand. Upon standing, the mixture separated into a toluene phase, an aqueous phase, and a solid (cellulose fiber) from the top. The toluene phase was collected and removed using a pipette, and the aqueous phase and solid were stirred with an impeller for 3 hours to disperse the clumped cellulose fiber and extract the dissolved components remaining in the fiber. Thereafter, filtration was performed using filter paper with a pore size of 5 μm to obtain filtrate (1) and filtrate (1). 100 mL of water was added to the obtained filtrate (1), and the mixture was stirred and then filtered to obtain filtrate (2) and filtrate (2). The obtained filtrate (1) and filtrate (2) were combined to obtain biomass composition (1). The filtrate (2) was washed with water, a 0.15% aqueous sodium bicarbonate solution, and water in this order, and the water was removed to recover solid content (1).

[0145] The resulting biomass composition (1), toluene phase, and solid content (1) were each dried, and their ratios (yields) to the dry weight of the raw cedar wood flour were determined. As a result, the yield of biomass composition (1) was 56.5 wt%, the yield of the toluene phase component was 4.6 wt%, and the yield of solid content (1) was 41.2 wt%.

[0146] The resulting biomass composition (1) was analyzed by the following method, and the neutral sugar content was 10.8% by weight, the lignin content was 0.3% by weight, and the total of the neutral sugar and lignin contents was 11.1%. The neutral sugar content in the raw cedar wood flour was 55.7% by weight, the lignin content was 35.6% by weight, and the total was 91.3%, indicating that the neutral sugar and lignin contents in biomass composition (1) were significantly reduced.

[0147] <Method for measuring neutral sugar content and lignin content> 1. 0.3 mL of 72 wt% sulfuric acid was added to 20 mg of dried biomass composition and stirred at 30°C for 1 hour. 2. 8.4 mL of water was added, and the mixture was heated at 120°C for 1 hour using an autoclave. 3. The reaction product after thermal decomposition was centrifuged (3500 rpm x 10 minutes) to separate the supernatant and precipitate. The precipitate was treated as lignin, washed with water until neutral, and then freeze-dried for 12 hours or more to completely dry it, after which its weight was measured. 4. The supernatant obtained by the centrifugation was neutralized with barium carbonate (the pH of the supernatant was adjusted to 6-8). The neutralized supernatant was then filtered through a 0.22 μm syringe filter (product name "FILTSTAR Syringe Filter", manufactured by Hawach Scientific) and analyzed by HPLC. The neutral sugar concentration was calculated using a previously prepared calibration curve. Calibration curves were prepared for glucose, mannose, xylose, galactose, and arabinose, and the concentrations in the measurement solutions were quantified, and the amounts of these monosaccharides were converted into the amounts of polysaccharides.

[0148] Measurement by HPLC was carried out under the following conditions: Apparatus: LC-4000 HPLC (manufactured by JASCO Corporation) Column: Aminex HPX-87P (300 x 7.8 mm) (manufactured by Bio-Rad Laboratories) Guard column: Micro-Guard Carbo-P Refill Cartridges (30 x 4.6 mm) (manufactured by Bio-Rad Laboratories) Column temperature: 85°C Mobile phase: water Mobile phase flow rate: 0.6 mL / min Detector: ELSD detector

[0149] IR measurements were performed on the obtained biomass composition (1), toluene phase, solid content (1), and raw material cedar wood flour. The results are shown in Figure 1. Note that the biomass composition (1) was measured before and after neutralization with sodium hydroxide. In Figure 1, 1 is the measurement result for the cedar wood flour, 2 is the measurement result for the solid content (1), 3 is the measurement result for the toluene phase, 4 is the measurement result for the biomass composition (1) after neutralization, and 5 is the measurement result for the biomass composition (1) before neutralization. The biomass composition (1) before neutralization characteristically has a peak at 1715 cm -1In the neutralized biomass composition (1), the peak is at 1585 cm -1 The shift to 1510 cm for solid (1) suggests that this is a carboxyl group. -1 The peaks derived from the aromatic rings of lignin around this point disappear, and the chart is similar to that of cellulose. The toluene phase has a characteristic peak at 2930 cm -1 Taking into consideration other analytical data, it can be estimated that the main components are lignans, terpenes, and their decomposition products.

[0150] The resulting biomass composition (1) was subjected to neutralization titration with 0.2 M aqueous NaOH using an autotitrator, and the carboxyl group content was estimated by subtracting the amount of catalyst used in the reaction. The result was 5.9 mmol / g (dry weight of biomass composition). During the neutralization titration of this biomass composition (1), no precipitate was observed within the pH range of 2 to 7, and the biomass composition was completely dissolved in water.

[0151] Biomass composition (1) was added to 1 g of an aqueous solution having a pH of 2 to 14 at room temperature, and 0.03 g was dissolved.

[0152] In addition, the contents of the major elements (N, P, K, Fe) in the biomass composition (1) and the solid content (1) were analyzed using ICP-MS for P, K, and Fe in samples wet-decomposed with concentrated sulfuric acid and concentrated nitric acid, and N was measured by CHN elemental analysis. The results are shown in Table 1 below. It can be seen that most of the elements contained in the cedar wood flour are contained in the biomass composition (1), and the element concentrations are higher.

[0153]

[0154] Example 2 1 g of the biomass composition (1) and 9 g of 1-propanol were mixed by stirring and then allowed to stand, resulting in the formation of a precipitate. The precipitate was centrifuged (3,500 rpm x 5 minutes) and its dry weight was measured. As a result, the precipitate accounted for 19% by weight of the biomass composition (1).

[0155] ATR-IR measurement was performed on the 1-propanol soluble matter and 1-propanol insoluble matter (precipitate) of the biomass composition (1). Furthermore, ATR-IR measurement was also performed on a mixture of cellulose and hemicellulose as an example of a polysaccharide. The results are shown in FIG. 2. 1 in FIG. 2 is the measurement result for the mixture of cellulose and hemicellulose, 2 is the measurement result for the 1-propanol insoluble matter, and 3 is the measurement result for the 1-propanol soluble matter. From FIG. 2, it can be seen that although both the 1-propanol soluble matter and the 1-propanol insoluble matter have carboxy groups, their structures are significantly different. Furthermore, it can be seen that the 1-propanol soluble matter has more carboxy groups than the 1-propanol insoluble matter and contains highly pure mono- and / or polycarboxylic acids. On the other hand, the 1-propanol insoluble matter has a peak at 800 to 1200 cm -1 It has a structure characteristic of sugars and is found to contain polysaccharide-derived substances.

[0156] Example 3 The same procedure as in Example 2 was carried out except that ethanol was used instead of 1-propanol. As a result, the amount of precipitate was 10% by weight of the biomass composition (1).

[0157] Example 4 The procedure was carried out in the same manner as in Example 2, except that methanol was used instead of 1-propanol. As a result, the amount of precipitate was 4% by weight of the biomass composition (1).

[0158] Example 5 Biomass composition (1) was subjected to ultrafiltration (MWCO: 5000 and 3000) to separate the filtrate from the solid. When the dry weight was measured, the filtrate was 33% and the filtrate was 67% for the MWCO of 3000, and the filtrate was 30% and 70% for the MWCO of 5000.

[0159] ATR-IR measurement was carried out on the filtrate and the filtrate separated by MWCO 5000. The results are shown in Figure 3. In Figure 3, 1 is the measurement result of the filtrate, and 2 is the measurement result of the filtrate. It can be seen that both the filtrate and the filtrate have many carboxy groups. The amount of carboxy groups was measured to be 2.9 mmol / g for the filtrate and 7.2 mmol / g for the filtrate.

[0160] Furthermore, the filtrate obtained by ultrafiltration was measured by HPLC. The results are shown in the table below. The HPLC measurement was carried out under the following conditions: Column: Shodex SH1011, Elution: 20 mM H2SO4, Flow rate: 0.6 mL / min, Column temperature: 60°C, Detector: UV 210 nm

[0161]

[0162] From the above, it was found that the filtrate obtained by ultrafiltration contained mono- and polycarboxylic acids having a molecular weight of 200 or less.

[0163] Example 6: In a round-bottom flask, 20 g of cedar wood flour (containing 10% by weight of moisture) milled using a Willey mill (1000 μm pass), 5.2 mmol of 1-methyl-3-(3-sulfopropyl)imidazolium, 4-methylbenzenesulfonate (manufactured by Angene) as a catalyst, 60 mL of 30% hydrogen peroxide solution, and 140 mL of toluene as a solvent were placed, and the mixture was stirred with a stirring blade at 60 °C for 24 hours to obtain a reaction solution. After allowing the reaction solution to cool, it was filtered using filter paper with a pore size of 5 μm to obtain a residue. Next, methanol was added to wash the residue, and the residue was filtered. 200 mL of water was added to the residue, and the mixture was stirred and mixed to extract, followed by filtration to recover the aqueous phase. The recovered aqueous phase was dried, and the yield of the aqueous phase component was 9.2% by weight. The aqueous phase contained 41.4% neutral sugars by weight, 8.1% lignin by weight, and 49.5% total neutral sugar and lignin content. The aqueous phase was found to contain a large amount of hemicellulose-derived components. The carboxyl group content was 1.2 mmol / g.

[0164] To summarize the above, the configuration of the present disclosure and its variations are described below. [1] A method for producing a biomass composition, comprising the steps of Step 1 and Step 2-1, or Steps 1 and 2-2, below, to obtain a biomass composition containing mono- and / or polycarboxylic acids and having a total neutral sugar content and lignin content of 70% by weight or less, as calculated by the following method. Step 1: A reaction system is charged with plant-derived biomass, a solvent containing at least a portion of water, and a peroxide and / or peracid, and the resulting mixture is reacted. Step 2-1: An aqueous phase is separated from the reaction solution after Step 1. Step 2-2: Water and / or a water-insoluble organic solvent is added to the reaction solution after Step 1, followed by liquid separation, and the aqueous phase is separated. <Method for Measuring the Neutral Sugar Content and Lignin Content> 1. 0.3 mL of 72% by weight sulfuric acid is added to 20 mg of a dried biomass composition, and the mixture is stirred at 30°C for 1 hour. 2. 8.4 mL of water is added, and the mixture is heated and decomposed in an autoclave at 120°C for 1 hour. 3. The reaction product after thermal decomposition is centrifuged to separate the supernatant and precipitate. The precipitate is regarded as lignin, washed with water, dried, and then weighed. 4. The supernatant obtained by the centrifugation is neutralized, and the centrifuged supernatant is filtered through a 0.22 μm syringe filter and analyzed by high-performance liquid chromatography to determine the neutral sugar concentration and calculate the content of neutral sugar components in the biomass composition. [2] The method for producing a biomass composition according to [1], further comprising one or more of the following steps 3 to 5: Step 3: The obtained aqueous phase is mixed with a water-soluble organic solvent to precipitate insoluble components. Step 4: The obtained aqueous phase is subjected to a filtration treatment using an ultrafiltration membrane to fractionate it. Step 5: A flocculant that interacts with carboxy groups is added to the obtained aqueous phase to precipitate it. [3] The method for producing a biomass composition according to [1] or [2], wherein the obtained biomass composition has a carboxy group content of 1 millimole or more per gram of dry weight. [4] The method for producing a biomass composition according to any one of [1] to [3], wherein the obtained biomass composition is soluble in an aqueous solution having a pH of 2 to 7. [5] The method for producing a biomass composition according to any one of [1] to [4], wherein the obtained biomass composition contains nitrogen, potassium, and iron, and the total content of nitrogen, potassium, and iron in the dry matter of the biomass composition is 1000 ppm by weight or more.[6] The method for producing a biomass composition according to any one of [1] to [5], wherein the mono- and / or polycarboxylic acid is at least one compound selected from mono- and / or polycarboxylic acids having a molecular weight of 200 or less and polycarboxylic acids having a molecular weight cutoff by ultrafiltration of 3000 or more. [7] A biomass composition containing at least one compound selected from mono- and / or polycarboxylic acids having a molecular weight of 200 or less and polycarboxylic acids having a molecular weight cutoff by ultrafiltration of 3000 or more, wherein the total of the neutral sugar content and lignin content measured by the following method is 70% by weight or less. <Method for measuring the neutral sugar content and lignin content> 1. To 20 mg of dried biomass composition, 0.3 mL of 72% by weight sulfuric acid is added and stirred at 30°C for 1 hour. 2. 8.4 mL of water is added and the mixture is heated and decomposed in an autoclave at 120°C for 1 hour. 3. The reaction product after the heat decomposition is centrifuged to separate the supernatant and precipitate. The precipitate is regarded as lignin, washed with water, dried, and then weighed. 4. The supernatant obtained by the centrifugation is neutralized, and the centrifuged supernatant is filtered through a 0.22 μm syringe filter and analyzed by high-performance liquid chromatography to determine the neutral sugar concentration and calculate the content of neutral sugar components in the biomass composition. [8] The biomass composition according to [7], which has a carboxyl group content of 1 millimole or more per gram of dry weight of the biomass composition. [9] The biomass composition according to [7] or [8], which is soluble in an aqueous solution of pH 2 to 7.

[10] The biomass composition according to any one of [7] to [9], which contains nitrogen, potassium, and iron, and whose total content of nitrogen, potassium, and iron in the dry matter of the biomass composition is 1,000 ppm by weight or more.

[0165] According to the method for producing a biomass composition disclosed herein, a biomass composition containing a high concentration of lignin-derived mono- and / or polycarboxylic acids can be produced from plant-derived biomass. Furthermore, the biomass composition exhibits little coloration and is soluble in aqueous solutions over a wide range of pH (particularly pH 2 to 7). Therefore, it can be used as a flocculant, dispersant, water absorbent, chelating agent, etc. It is also useful as a raw material for plastics and chemical products. Furthermore, since the biomass composition contains nitrogen, potassium, and iron, it is useful as a soil conditioner, fertilizer, etc.

Claims

1. A method for producing a biomass composition, comprising the steps of Step 1 and Step 2-1, or Steps 1 and 2-2, below, to obtain a biomass composition containing mono- and / or polycarboxylic acids and having a total neutral sugar component content and lignin content of 70% by weight or less, as calculated by the following method: Step 1: A reaction system is charged with plant-derived biomass, a solvent containing at least a portion of water, and a peroxide and / or peracid, and the mixture is reacted. Step 2-1: An aqueous phase is separated from the reaction liquid after Step 1. Step 2-2: Water and / or a water-insoluble organic solvent is added to the reaction liquid after Step 1, followed by liquid separation, and the aqueous phase is separated. <Method for measuring neutral sugar component content and lignin content> 1. 0.3 mL of 72% by weight sulfuric acid is added to 20 mg of a dried biomass composition, and the mixture is stirred at 30°C for 1 hour.

2. Add 8.4 mL of water and autoclave for 1 hour at 120°C.

3. After the thermal decomposition, the reaction mixture is centrifuged to separate the supernatant and precipitate. The precipitate is taken as lignin, washed with water, dried, and weighed.

4. The supernatant obtained by the centrifugation is neutralized, and the centrifuged supernatant is filtered through a 0.22 μm syringe filter and analyzed by high performance liquid chromatography to determine the neutral sugar concentration and calculate the content of neutral sugar components in the biomass composition.

2. The method for producing a biomass composition according to claim 1, further comprising carrying out one or more of the following steps 3 to 5: Step 3: The resulting aqueous phase is mixed with a water-soluble organic solvent to precipitate insoluble components. Step 4: The resulting aqueous phase is subjected to filtration using an ultrafiltration membrane to fractionate it. Step 5: A flocculant that interacts with carboxy groups is added to the resulting aqueous phase to precipitate it.

3. A method for producing a biomass composition according to claim 1 or 2, wherein the carboxyl group content per gram of dry weight of the obtained biomass composition is 1 millimole or more.

4. The method for producing a biomass composition according to claim 1 or 2, wherein the obtained biomass composition is soluble in an aqueous solution having a pH of 2 to 7.

5. A method for producing a biomass composition according to claim 1 or 2, wherein the obtained biomass composition contains nitrogen, potassium, and iron, and the total content of nitrogen, potassium, and iron in the dry matter of the biomass composition is 1000 ppm by weight or more.

6. A method for producing a biomass composition described in claim 1 or 2, wherein the mono- and / or polycarboxylic acid is at least one compound selected from mono- and / or polycarboxylic acids having a molecular weight of 200 or less and polycarboxylic acids having a molecular weight cutoff by ultrafiltration of 3000 or more.

7. A biomass composition containing at least one compound selected from mono- or polycarboxylic acids having a molecular weight of 200 or less and polycarboxylic acids having a molecular weight cutoff by ultrafiltration of 3000 or more, wherein the total of the neutral sugar content and lignin content measured by the following method is 70% by weight or less. <Method for measuring the neutral sugar content and lignin content> 1. Add 0.3 mL of 72% by weight sulfuric acid to 20 mg of dried biomass composition and stir at 30°C for 1 hour.

2. Add 8.4 mL of water and autoclave for 1 hour at 120°C.

3. After the thermal decomposition, the reaction mixture is centrifuged to separate the supernatant and precipitate. The precipitate is taken as lignin, washed with water, dried, and weighed.

4. The supernatant obtained by the centrifugation is neutralized, and the centrifuged supernatant is filtered through a 0.22 μm syringe filter and analyzed by high performance liquid chromatography to determine the neutral sugar concentration and calculate the content of neutral sugar components in the biomass composition.

8. The biomass composition of claim 7, having a carboxyl group content of 1 millimole or more per gram of dry weight of the biomass composition.

9. The biomass composition according to claim 7 or 8, which is soluble in an aqueous solution having a pH of 2 to 7.

10. A biomass composition according to claim 7 or 8, which contains nitrogen, potassium, and iron, and the total content of nitrogen, potassium, and iron in the dry matter of the biomass composition is 1000 ppm by weight or more.

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