JP2011224499A - Method for producing sugar or its derivative - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing sugar or its derivative by decomposing and saccharizing lignocellulose-based actual biomass more quickly with high efficiency.SOLUTION: A solid acid catalyst and lignocellulose-based actual biomass are brought into contact with each other under irradiation of microwaves to decompose and saccharize the lignocellulose-based real biomass.

Description

  The present invention relates to a method for producing sugar or a derivative thereof, and more particularly, to a preferable method for producing sugar or a derivative thereof by decomposing and saccharifying cellulosic biomass.

  In recent years, attempts have been made to convert and use recyclable biomass produced by plants such as cellulose into useful substances. When cellulose is used, it is preferable to decompose cellulose into its constituent monosaccharides, oligosaccharides or derivatives thereof. The decomposition product thus obtained can be metabolized by organisms including many microorganisms and can be easily used industrially.

  Cellulose naturally contains cellulose crystal structure and is complexed with hemicellulose and lignin having a complicated three-dimensional structure (hereinafter, the cellulosic material having such a complex structure is referred to as lignocellulosic real biomass). Present in the plant body. For this reason, cellulose is hardly degradable. In addition, as a method for decomposing cellulose, conventionally, there are an enzyme method using an enzyme derived from a cellulolytic microorganism, a sulfuric acid method using sulfuric acid, and the like. However, in the enzymatic method, the degradation rate is slow, and in order to degrade cellulose in the plant body, that is, cellulose in lignocellulosic real biomass, pretreatment of such real biomass was essential. Moreover, since the enzyme is expensive, high productivity could not be obtained. On the other hand, in the sulfuric acid method, lignocellulosic real biomass can be directly processed, but it requires a lot of processes for separation of saccharified cellulose and tends to be excessively decomposed.

  Therefore, in recent years, in order to facilitate the saccharification of cellulose in lignocellulosic real biomass, development of a pretreatment method for lignocellulosic real biomass, a catalyst having high decomposition activity, and the like has been advanced. For example, various methods have been attempted in which lignocellulose-based real biomass is pretreated with microwaves and then decomposed with an enzyme (Non-Patent Documents 1 and 2). In addition, a method of saccharifying lignocellulosic real biomass using a solid catalyst (Non-patent Document 3) has also been attempted. Furthermore, studies have been made to promote enzymatic saccharification of lignocellulosic real biomass by pretreatment by mechanochemical treatment (Non-patent Document 4).

Process Biochemistry, 40, 3082-3086 (2005) Biosystems Engineering, 93, 279-283 (2006) Angew. Chem. Int. Ed., 45, 5161-5163 (2006) J. Jpn. Pet. Inst., Vol.51, No.5, 264-273 (2008)

  However, although the separation of cellulose from lignocellulosic real biomass is promoted by pretreatment with microwaves, the conversion efficiency finally obtained by enzyme treatment is excellent considering the process and enzyme cost I couldn't. Even when a solid catalyst is used, high conversion efficiency has not been obtained. Furthermore, even if mechanochemical treatment is used, the pretreatment time and the enzyme treatment time are still considerable, and efficient saccharification is difficult.

  Accordingly, an object of the present invention is to provide a method for producing sugar or a derivative thereof by degrading and saccharifying lignocellulosic real biomass more quickly and efficiently.

  The present inventors can promote the saccharification reaction beyond the expectation by contacting the lignocellulosic real biomass and the solid acid catalyst under microwave irradiation, and the cellulose can be obtained without any pretreatment for the lignocellulosic real biomass. And he discovered that hemicellulose can be rapidly and efficiently decomposed and saccharified, and the present invention was completed. According to the present invention, the following means are provided.

  According to the present invention, the step of bringing a solid acid catalyst and lignocellulosic real biomass into contact with each other under microwave irradiation to decompose the lignocellulosic real biomass and saccharify the sugar or a derivative thereof. A manufacturing method is provided. In this production method, the lignocellulosic real biomass may have an average particle size of 10 μm to 10 mm. The lignocellulose-based real biomass and the solid acid catalyst may be contacted at 130 ° C. or higher and 200 ° C. or lower. According to this production method, glucose, its disaccharide and oligosaccharide can be obtained from cellulose, and xylose, its disaccharide and oligosaccharide can be obtained from hemicellulose.

Further, the solid acid catalyst is preferably a solid having a Bronsted acid point, and the Bronsted acid point is selected from the group consisting of —OH group, —CO ₂ H group and —SO ₃ H group. It can be 1 type or 2 types or more. It is preferable that graphite oxide (GO) is provided as the solid acid catalyst. Also preferred graphene having a -SO ₃ H group.

  In the production method of the present invention, it is preferable that the saccharification step uses a microwave irradiation apparatus including a cavity resonator as a reaction chamber.

  According to the present invention, there is provided a method for producing a saccharified product of hemicellulose from lignocellulosic real biomass, wherein the lignocellulosic real biomass and solid acid catalyst are brought into contact with each other under microwave irradiation. A method is provided comprising a saccharification step of saccharifying xylose. Hemicellulose can be efficiently decomposed by contacting lignocellulosic real biomass with a solid acid catalyst under microwave irradiation.

It is a figure which shows the saccharification result under the microwave irradiation of a cedar fine powder and a solid acid catalyst. It is a figure which shows the saccharification result using the oil bath of a cedar fine powder and a solid acid catalyst. It is a figure which shows a saccharification result when a eucalyptus fine powder, a eucalyptus coarse powder, and a solid acid catalyst are made to contact at 160 degreeC under microwave irradiation. It is a figure which shows the saccharification result at 160 degreeC in the oil bath of a eucalyptus fine powder and a eucalyptus coarse powder. It is a figure which shows the relationship between the reaction temperature of a bagasse 1 fine powder, a glucose saccharification rate, and a xylose saccharification rate. It is a figure which shows the relationship between the reaction temperature, glucose saccharification rate, and xylose saccharification rate of bagasse 2 fine powder and bagasse 2 coarse powder.

  The present invention relates to a method for producing sugar and its derivatives from lignocellulosic real biomass. According to the present invention, lignocellulosic real biomass can be efficiently decomposed to produce sugar or a derivative thereof. More specifically, glucose and xylose can be rapidly obtained from lignocellulosic real biomass while suppressing pretreatment such as pulverization of the lignocellulosic real biomass. That is, the inventors of the present invention performed microwave treatment in the presence of a solid acid catalyst for each of the lignocellulosic real biomass coarse powder and fine powder, and surprisingly, the particle size of the lignocellulosic real biomass was Despite this, they have found that they exhibit almost the same conversion efficiency behavior. This has largely reversed the common knowledge of those skilled in the art that the particle size of lignocellulosic real biomass powder greatly affects the subsequent saccharification efficiency.

  The present inventors infer that the improvement in the degradation performance of lignocellulosic real biomass by solid acid catalyst and microwave irradiation is due to the synergistic effect of the solid acid catalyst and microwave irradiation. That is, the lignocellulosic real biomass is coordinated or adsorbed to the solid acid catalyst, so that the molecular bond in the lignocellulosic real biomass is weakened, and those having polar functional groups such as hydroxyl groups It is thought that the reaction rate increases due to the action.

  On the other hand, a molecule having a dipole, such as a molecule having a polar group, selectively absorbs microwaves to obtain energy such as rotational motion and promotes polarization. In the microwave reaction field, the molecule having a dipole selectively absorbs the microwave and is rapidly heated by frictional heat due to rotation or vibration. In particular, when it has a hydroxyl group, the effect is considered to be increased. Since water, cellulose, and the solid acid catalyst all have a hydroxyl group, microwave absorption is large, and synergistic effects increase the reaction rate. It is thought. Furthermore, the microwave heating can reduce the activation energy as compared with the conventional external heating, and the lignocellulosic real biomass and the solid acid catalyst are both dielectrics and the reaction proceeds in an electric field. It is considered that a reaction (hydrolysis reaction) that cleaves a chemical bond (such as a glycoside bond) is promoted by a synergistic effect of such actions. In addition, the above reasoning does not restrain this invention.

  According to the production method disclosed in this specification, lignocellulosic real biomass can be decomposed quickly and efficiently at a low temperature as compared with the conventional method. In particular, even if it is not a finely pulverized sample having an average particle diameter of less than 100 μm, it can be efficiently decomposed. Moreover, since rapid heating and cooling can be performed by irradiation with microwaves, excessive decomposition of the decomposed product can be suppressed, so that high yield and high quality saccharification can be expected. Furthermore, after the reaction, a liquid (solution) containing a saccharified product can be easily separated by a conventional solid-liquid separation means such as filtration or centrifugation, and the solid acid catalyst can be separated and recovered from the reaction system. Furthermore, it is easy to repeatedly use the recovered catalyst. Furthermore, since saccharification can be performed without using chemicals such as sulfuric acid, the method has an advantage of reducing the environmental load. In addition, since microwaves can selectively reduce the molecular weight of lignin, it is possible to promote the decomposition and saccharification of cellulose from real biomass. Hereinafter, embodiments for carrying out the present invention will be described in detail.

(Method for producing sugar or derivative thereof)
The production method of the present invention can comprise a step of bringing a solid acid catalyst and lignocellulosic real biomass into contact with each other under microwave irradiation to decompose and saccharify the lignocellulosic real biomass. As a result, glucose and xylose, which are useful substances that many organisms can metabolize lignocellulosic real biomass, which is reproducible or unused, are also useful substances that can be converted into industrially useful industrial materials. Can be efficiently converted into monosaccharides, oligosaccharides or derivatives thereof.

(Lignocellulosic real biomass)
In the present invention, lignocellulosic real biomass refers to a material containing at least cellulose and having hemicellulose and lignin and having these composite structures in a plant body. Here, examples of cellulose include a polymer in which glucose is polymerized by β-1,4-glycoside bonds and derivatives thereof. The degree of polymerization of glucose is not particularly limited. The cellulose may be crystalline cellulose or non-crystalline cellulose. In addition, examples of the derivative include derivatives such as carboxymethylation, aldehyde formation, or esterification. Cellulose may be cellooligosaccharide or cellobiose, which is a partially decomposed product thereof. Further, cellulose may be a complex with β-glucoside, which is a glycoside, and pectin.

  Examples of lignocellulosic real biomass include lignocellulosic materials in a state in which lignin and the like are combined in the woody parts and leaf parts of woody plants such as cedar, cypress and eucalyptus, and the leaves, stems and roots of herbaceous plants. . Examples of such lignocellulosic materials include rice straw, wheat straw, corn stover, bagasse and other agricultural waste, collected trees, branches, dead leaves, etc. or chips obtained by defibrating these, sawdust, chips, etc. It may be a waste from a sawmill factory, a forest residue such as thinned wood or damaged trees, and a construction waste.

  The lignocellulose-based real biomass preferably has an average particle size of 10 μm or more and 10 mm or less. Even in this range, the lignocellulosic real biomass is efficiently decomposed. More preferably, it is 100 μm or more and 10 mm or less. This is because energy costs are required to make the average particle diameter less than 100 μm, and when the average particle diameter exceeds 10 mm and becomes too large, the saccharification rate tends to decrease. Considering the energy cost of the pulverization treatment, it is more preferably 150 μm or more, further preferably 200 μm or more, further preferably 250 μm or more, and further more preferably 500 μm or more. In consideration of the saccharification rate, the upper limit is more preferably 8 mm or less, further preferably 6 mm or less, still more preferably 5 mm or less, still more preferably 4 mm or less, It is also preferable that it is 2 mm or less. The lignocellulosic real biomass having such an average particle size can be obtained by pulverizing for an appropriate time by a pulverization method known to those skilled in the art such as a vibration mill.

  As the average particle size of the lignocellulose-based real biomass, for example, a sieving method or a laser diffraction / scattering method is used. For example, after sieving a sample using a plurality of sieves, the weight of the powder remaining on the sieve was measured, the weight fraction was calculated, and was shown as 50% of the integrated percentage. In particular, in the case of fine powder, it has been confirmed that an average particle diameter comparable to that of the sieving method can be obtained as a measurement result by using the laser diffraction scattering method together.

(Solid acid catalyst)
The solid acid catalyst used in this invention will not be specifically limited if it is a solid acid catalyst which has the activity which can decompose | disassemble lignocellulosic real biomass. From the viewpoint of decomposing cellulose in lignocellulosic real biomass, the solid acid catalyst preferably has an activity of cleaving at least β-1, 4 glycosidic bonds between glucoses. Moreover, from the viewpoint of decomposing various hemicelluloses, it is preferable to have an activity of cleaving glycosidic bonds between the constituent monosaccharides of such hemicelluloses.

The solid acid catalyst preferably has a Bronsted acid point. By having a Bronsted acid point, examples of the dipole Bronsted acid point include oxygen acids such as —OH group, —CO ₂ H group, —SO ₃ H group, and PO ₃ H group. However, it is not limited to these. A —CO ₂ H group and a —SO ₃ H group are preferable. This is because these carbon-based solid materials having Bronsted acid points are effective in decomposing lignocellulosic real biomass. Note that “the solid acid catalyst has a Bronsted acid point” also includes the case where the solid acid catalyst has a Bronsted acid point in the presence of water. That is, it may be a site that functions as an acid point as a result of a certain element (functional group, ion, etc.) on the solid acid catalyst strongly attracting the hydroxide ionic liquid in the presence of water. Whether the solid acid catalyst has a Bronsted acid point can be determined by a known method using infrared spectroscopy. For example, it is possible to adsorb pyridine on the surface of the solid acid catalyst and detect specific absorption (1540 cm ⁻¹ ) of pyridinium ions adsorbed to the Bronsted acid point.

  The solid acid catalyst may be a multi-way catalyst having other catalytic active sites including a Lewis acid point in addition to the Bronsted acid point as described above. The active site is appropriately selected depending on the type of substrate. In consideration of the effect of microwave irradiation, the active site is preferably a catalytically active site having a dipole.

  Examples of the solid acid catalyst include carbon-based solid materials, silicate compounds, and solid superacids. These can function as solid acid catalysts for cellulosic materials irradiated with microwaves. As a solid acid catalyst, 1 type (s) or 2 or more types can be selected suitably, and can be used.

(Carbon-based solid material)
The carbon-based solid material preferably includes graphene, graphite oxide, activated carbon, and derivatives thereof. Of these, graphite oxide (GO) and its derivatives, and activated carbon and its derivatives are preferable. This is because all of these carbon-based solid materials inherently have Bronsted acid points on the surface. More preferably, graphite oxide is provided. In addition, graphene having a —SO ₃ H group is provided.

As the graphite oxide, those synthesized by a known method can be used. Such methods include, for example, Hammers WS, Offeman RE.J.Am.Chem.Soc., 1958,80,1339, Brodie BC.Ann.Chim.Phys.1860,59,466, Staudenmaier L.Ber.Dtsch.Chem. Ges. 1898, 31, 1484. Typically, the method of Hummers et al. Specifically, put graphite powder and sodium nitrate in a reaction vessel, add an appropriate amount of concentrated sulfuric acid (d1.84), cool it in an ice bath, and use potassium permanganate powder as an oxidizing agent for about 1 hour. And then stir for another 2 hours. After returning to room temperature and continuing stirring, the resulting slurry-like reaction mixture is slowly added to water, and the precipitate is removed by centrifugation, washed and dried under reduced pressure to convert graphite oxide (GO) as a brown powder. Obtainable. Any natural or artificial graphite can be used as the starting material. Graphite oxide can usually be provided with OH groups and CO ₂ H groups.

Derivatives of carbon-based solid materials, for example, sulfonated products (sulfated graphite oxide (SGO)), which is one of graphite oxide derivatives, and graphene (graphene sulfonated products) having —SO ₃ H groups are known documents. (“Synthesis Conditions and Catalysis of Carbon-Based Solid Strong Acid” The Chemical Society of Japan 85th Spring Meeting (2005), 2B5-43, JP-A No. 2004-238111, JP-A No. 2009-25283) In addition, for example, graphite oxide can be obtained by heat treatment in fuming sulfuric acid. The obtained powder is preferably in its H ⁺ form.

  For example, graphite oxide and its sulfonated product and graphene sulfonated product do not show high cellulose decomposition activity under microwave irradiation, but show high lignocellulosic real biomass decomposition activity under microwave irradiation. Can show. Therefore, graphite oxide and its sulfonated product and graphene sulfonated product are preferably used as a solid acid catalyst used under microwave irradiation.

Activated carbon is a carbon-based porous material activated by chemically or physically treating various carbon-containing materials selected from plant materials, coal materials, petroleum materials, and moving material materials. The sulfonated product of activated carbon can be obtained, for example, by heat-treating activated carbon in fuming sulfuric acid. The resulting powder is preferably in its H ⁺ form.

(Silicate compound)
The silicate compound means a silicate compound or a salt thereof and a compound having a polymerized structure thereof. Silicate compounds may be collected from nature, may be processed natural products, or may be artificially or semi-artificially synthesized. Preferably, it is a silicate compound having a two-dimensional or three-dimensional network skeleton or a compound having a polymerized structure of the salt.

Examples of the silicate compound include clay minerals. The clay mineral is a layered compound having a polysiloxane structure at least in part. In general, clay minerals are formed in layers in a sheet in which metal ions such as aluminum, magnesium, sodium, calcium, and silicate compounds are connected. Examples of the clay mineral include smectite clay minerals such as montmorillonite, beidellite, nontronite, saponite, hectorite, and acid clay. In addition, modified clay minerals obtained by acid-treating them to modify H ⁺ are also suitable clay minerals for the present invention. The H ⁺ -modified clay mineral here refers to the use of the clay mineral as a raw material, and by elution of metal ions (Al, Mg, etc.) contained in the crystal of the clay mineral by acid treatment at a high temperature, newly adding excess silicic acid. It was created and is insoluble in water and shows Bronsted acidity. As an example of the production method, for example, activated clay, after crushing smectite clay minerals such as montmorillonite, granulated, treated with sulfuric acid and water at 90 degrees for several hours, after sufficient washing, It can be obtained by drying at 110 ° C. H ⁺ modified clay minerals can be obtained commercially as well as synthesized as described above. Typical examples of the H ⁺ -modified clay mineral include activated clay and K-10 montmorillonite.

Examples of the silicate compound include zeolite which is an aluminosilicate having fine pores in the crystal. Zeolite may be natural or synthetic, but synthetic zeolite is preferably used in view of availability and homogeneity. Examples of zeolite include ZSM-5, mordenite, beta zeolite, Y-type zeolite, MCM-22, FSM-16, aluminum phosphate condensate (AlPO ₄ -n), TS-1, TS-2, and SAPO series. Is mentioned. Zeolite also includes zeolite-related compounds such as mesoporous silica, organic / inorganic hybrid, organic complex structure (Metal-Organic-Framework), etc. "Science & Technology Co., Ltd. 2008). Further, the zeolite may be H ⁺ type zeolite obtained by calcining NH ₄ ⁺ type into a H ⁺ type by a known method. The above-mentioned various zeolites are commercially available, edited by Hiroo Tominaga, “Zeolite Science and Application”, Kodansha Scientific 1987, Yoshio Ono and Kenaki Yajima “Zeolite Science and Engineering” Kodansha Science Tyfik 2000, supervised by Akira Takashi and Yoichi Nishimura, “New Developments in Zeolite Catalyst Development”, CMC Publishing 2004, etc., can be synthesized by those skilled in the art based on these descriptions. As the zeolite, one or more kinds of various zeolites can be appropriately selected and used.

(Solid super strong acid)
The solid superacid is “Hammet acidity function (H ₀ ) <− 11.93” (“superstrong acid / superbase” by Kozo Tabe and Ryoji Noyori, Kodansha Scientific, 1980), 100% sulfuric acid. A solid acid exhibiting stronger acid strength. Examples of the solid super strong acid used in the present invention include those having a sulfate or a tungsten oxide supported on a hydroxide or oxide such as titanium, zirconium, hafnium, iron, aluminum, silicon, or tin as a carrier. It is done. Specifically, sulfated zirconia (SO ₄ / ZrO ₂ ), SO ₄ / SnO ₂ , SO ₄ / HfO ₂ , SO ₄ / TiO ₂ , SO ₄ / Al ₂ O ₃ , SO ₄ / Fe ₂ O ₃ , SO ₄ / SiO ₂ , WO ₃ / ZrO ₂ , MoO ₃ / ZrO ₂ , WO ₃ / SnO ₂ , WO ₃ / TiO ₂ , WO ₃ / Fe ₂ O ₃ and B ₂ O ₃ / ZrO ₂ . As the solid acid catalyst, one or more selected from such solid superacids are appropriately selected and used.

The solid superacid can be obtained, for example, by carrying a calcination after supporting a sulfate radical or a tungsten oxide precursor on the carrier as described above. Examples of sulfate radical precursors include sulfuric acid, ammonium sulfate, sulfuryl chloride, thionyl chloride, SO ₂ gas, and examples of tungsten oxide precursors include ammonium metatungstate and ammonium paratungstate. 12 tungstophosphoric acid and the like. As the loading method, a known appropriate method can be adopted, and after dissolving in a suitable solvent such as water, a method of suspending the carrier and drying the solvent can be adopted. When using a precursor that easily reacts with water such as sulfuryl chloride or thionyl chloride, it is desirable to use a solvent such as hexane or methylene chloride. For example, sulfated zirconia can be prepared by a method similar to the method for preparing sulfated zirconia by the Catalytic Society Reference Catalyst Committee. It is desirable to heat and dry before use and to wash away sulfate radicals released in water in advance.

  As a method for developing strong acidity, it is generally employed to calcine the catalyst on which the precursor thus obtained is supported. The firing temperature for this purpose is appropriately selected depending on the combination of the carrier and the sulfate radical precursor or the tungsten oxide precursor. Specifically, in the case of a sulfate group-zirconium oxide combination, the range is preferably 500 ° C. to 800 ° C., more preferably in the range of 600 ° C. to 700 ° C., and in the case of a tungsten oxide-zirconium oxide combination, preferably 700 ° C. It is -1,000 degreeC, More preferably, it is the range of 800 degreeC-900 degreeC. However, what is necessary is just to obtain what corresponds to the above-mentioned definition of super strong acid after baking, and it is not limited to these conditions. Confirmation that it is a super strong acid is, for example, `` J.Chem.Soc.Chem.Commun.1259 (1989) '', `` J.Chem.Soc.Chem.Commun.1148 (1979) '', `` J.Chem.Soc Chem. Commun. 1851 (1980) ”,“ J. Am. Chem. Soc. 101, 6439 (1979) ”, etc., can be carried out by skeletal isomerization of paraffin and measurement of acid strength.

(Microwave)
Although it does not specifically limit as a microwave, The frequency (about 300 MHz or more and about 30 GHz or less) used for the heating of water can be used. Preferably, it is 0.6 GHz or more and 10 GHz or less. A typical example is one having a frequency of about 2.45 GHz, but is not limited thereto. The frequency may be set according to the Bronsted acid point of the solid acid catalyst. The output is not particularly limited.

  The microwave irradiation is performed using a microwave irradiation apparatus including a cavity resonator for microwave irradiation. The cavity resonator is for resonating the microwave irradiated from the microwave generating means. The cavity resonator may be any of a single mode rectangular cavity resonator, a single mode cylindrical cavity resonator, or a multimode microwave oven (microwave oven). The single-mode cavity resonator has an advantage that the reaction tube contents can be rapidly heated, so that the reaction can be performed in an extremely short time. On the other hand, the multimode microwave oven does not need to control the resonance in the cavity resonator, and has an advantage that the reactant can be placed at an arbitrary position. From the viewpoint of heating rate and heating efficiency, the cavity resonator is preferably a single mode system.

  When the cavity resonator is a single mode system, the reaction vessel in which the substrate and the solid acid catalyst are introduced is inserted at the position where the electric field component in the cavity resonator is maximized (the position of the antinode of the standing wave). The On the other hand, when the cavity resonator is a multimode system, the position of the reaction vessel is not particularly limited. The cavity resonator is usually made of aluminum, copper, brass or the like, but stainless steel may be used when heat resistance is required.

  Further, in the case of the single mode method, the cross-sectional dimension of the cavity resonator is determined according to the microwave frequency so that resonance can be obtained. For example, in the case of a rectangular parallelepiped resonator, when the microwave frequency is 2.45 GHz, the cross-sectional dimension (height dimension in the direction perpendicular to the microwave traveling direction × width dimension) is about 55 mm × 110 mm. . Further, in this case, a reaction vessel is inserted in a direction perpendicular to the traveling direction of the microwave at the substantially center of the rectangular parallelepiped cavity resonator.

There are various single-mode electromagnetic field modes, but TE _10n (n is an integer) mode is preferably used in order to obtain a high electric field strength. Here, the first subscript “1” means that the number of standing waves (1/2 wavelengths) in the width direction of the rectangular parallelepiped cavity resonator is one. The second subscript “0” means that the standing wave in the height direction of the rectangular parallelepiped cavity resonator is zero. Furthermore, the third subscript “n” means that the number of standing waves along the microwave traveling direction of the rectangular parallelepiped cavity resonator is n. In order to increase the electric field strength, n is preferably 3 or less. The reactor used this time is n = 1.

  The resonance state of the cavity resonator is a state in which the frequency of the cavity resonator matches the microwave frequency. In this state, the microwave reflectivity (= reflected power × 100 / incident power) is almost zero. Become. However, since the cross-sectional dimensions of the cavity resonator are designed so as to obtain resonance when the cavity resonator is empty, a reaction vessel is inserted into the cavity resonator, or the contents are contained in the reaction vessel. In some cases, resonance may not be achieved. In such a case, it is necessary to adjust the resonance of the cavity resonator. For this reason, an instrument for changing the opening area of the opening into which the microwave is incident is provided at one end of the cavity resonator.

  In addition, about the medium, temperature conditions, pressure conditions, time conditions, etc. in a catalytic reaction, it can set suitably. The medium is not particularly limited, but preferably contains a polar solvent containing water from the viewpoint of promoting the reaction. Examples of the polar solvent include lower alcohols such as methanol, ethanol, and propanol, dimethyl sulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMAc) acetonitrile, and dioxane.

  In addition to the water contained in the cellulosic material, the water may be any of liquid, gas, and solid as long as it is supplied to the surface of the solid acid catalyst under microwave irradiation. As the medium, water, a polar organic solvent compatible / incompatible with water, a non-polar organic solvent compatible / incompatible with water, or a mixed solvent of two or more of these can be used. . The configuration of the medium is determined as appropriate. The catalytic reaction can also be carried out in a dispersed state while stirring in a suitable medium with the solid acid catalyst and the cellulosic material. The catalytic reaction may be carried out in a dispersed state by stirring with water and an incompatible organic solvent as a medium, or may be carried out in any of the separated two-phase systems.

  Although reaction temperature is not specifically limited, It can carry out at room temperature (1 degreeC or more) to 300 degrees C or less. Preferably, it is 80 degreeC or more and 250 degrees C or less. Even within this range, the cellulosic material can be efficiently decomposed. In particular, it is preferable to contact the solid acid catalyst and the lignocellulosic real biomass at 130 ° C. or higher and 200 ° C. or lower. Within this range, good saccharification rates from lignocellulosic real biomass to glucose and xylose can be ensured. If it is less than 130 ° C. and more than 200 ° C., the saccharification rate to xylose tends to decrease rapidly, and if it is less than 130 ° C. and more than 200 ° C., the saccharification rate to glucose tends to decrease. Preferably, it is 130 degreeC or more and 180 degrees C or less.

  In the case of herbaceous lignocellulosic real biomass such as bagasse, it is more preferably 130 ° C. or higher and 170 ° C. or lower. More preferably, it is 130 degreeC or more and 160 degrees C or less. More preferably, it is 135 degreeC or more and 155 degrees C or less, More preferably, it is 135 degreeC or more and 145 degrees C or less. In particular, such a temperature range is also a preferable temperature range for saccharification of xylose from herbaceous lignocellulosic real biomass. Moreover, even if it is a herbaceous type, 150 degreeC or more and 170 degrees C or less may be suitable for the kind of lignocellulosic real biomass. Further, preferably, 155 ° C. or more and 165 ° C. or less may be suitable.

  Furthermore, in woody lignocellulosic real biomass such as cedar, the temperature is preferably 150 ° C. or higher and 170 ° C. or lower, and more preferably 155 ° C. or higher and 165 ° C. or lower. Such a temperature range is a preferable temperature range for saccharification of xylose from woody lignocellulosic real biomass.

  In microwave treatment of lignocellulosic real biomass in the presence of a solid acid catalyst, the lignocellulosic real biomass can be appropriately dispersed in an appropriate reaction medium such as water. Typically, it is preferable to add lignocellulosic real biomass in a proportion of 1% by mass or more and 10% by mass or less with respect to the reaction medium. In addition, when the addition amount of lignocellulose-type real biomass with respect to a reaction medium increases, there exists a tendency for the conversion efficiency to glucose and xylose to fall. Preferably, they are 3 mass% or more and 7 mass% or less with respect to the reaction medium. Further, the amount of the solid acid catalyst added to the reaction medium is not particularly limited, but typically, the solid acid catalyst can be added at a ratio of 1% by mass to 10% by mass with respect to the reaction medium. In addition, when the addition amount of the solid acid catalyst with respect to a reaction medium falls, there exists a tendency for the conversion efficiency to glucose and xylose to fall. Preferably, they are 3 mass% or more and 7 mass% or less with respect to the reaction medium.

  In addition, when controlling decomposition | disassembly of lignocellulosic real biomass, you may make it cool the heating state by a microwave using a cooling means. The reaction time is not particularly limited. The reaction time is appropriately set according to the microwave irradiation output, and is usually from several minutes to several hours, but preferably within 60 minutes. This is because if it exceeds 60 minutes, the saccharification rate of xylose tends to decrease. More preferably, it is within 50 minutes.

  By such catalytic reaction, sugar or a derivative thereof can be obtained by decomposing lignocellulosic real biomass. Examples of the sugar include a constituent monosaccharide of hemicellulose in addition to glucose which is a constituent monosaccharide of cellulose. Examples of the sugar include cellulose-derived oligosaccharides having a molecular weight of 4000 or less (cellobiose, cellotriose, cellotetraose, cellohexaose, etc.) and hemicellulose-derived oligosaccharides. Derivatives include sugar alcohols, sugar esters, sugar thiols, sugar phosphates, sugar salts of these sugars, and internal dehydration products. Note that not all of these are generated by the catalytic reaction. The resulting sugar or derivative thereof differs depending on the reaction conditions and the like as well as the type of cellulosic material used for the substrate.

  The saccharification step of this production method is also a step suitable for saccharification of xylose from lignocellulosic real biomass. Therefore, this manufacturing method can also be implemented as a saccharification method of xylose from lignocellulosic real biomass. That is, production of saccharified hemicellulose from lignocellulosic real biomass, comprising a saccharification step of saccharifying xylose in lignocellulosic real biomass by contacting lignocellulosic real biomass with a solid acid catalyst under microwave irradiation A method is also provided. Therefore, for example, after the saccharification step of xylose from lignocellulose-based real biomass by microwave irradiation under a solid acid catalyst, the saccharification step of cellulose may be further performed on the processed product of the saccharification step. Cellulose saccharification usually requires a higher temperature than xylose saccharification. Therefore, by carrying out saccharification of xylose at a low temperature, it is possible to efficiently saccharify cellulose by reducing the lignocellulose structure at a low energy cost as a whole.

  As described above, according to the production method of the present invention, even lignocellulosic real biomass can be rapidly and efficiently decomposed and saccharified to obtain a sugar derived from lignocellulosic real biomass or a derivative thereof.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not limited to a following example.

  In this example, a microwave heating apparatus (2.45 GHz) that includes a single mode resonator (cavity) and can monitor temperature and pressure was used as the microwave irradiation apparatus. The reaction solution was prepared in a 5 ml pressure-resistant test tube, 0.03 g of cedar powder (average particle size of about 200 μm), 0.03 g of graphite oxide powder as a solid acid catalyst, and 3 ml of distilled water were added and stirred. Sealed with a bottle kit (aluminum seal cap with Teflon stopper). The reaction conditions were initial pressure 0.1 MPa, rapid heating while monitoring the temperature from room temperature by microwave irradiation, and after reaching 140 ° C., 160 ° C. and 190 ° C., respectively, maintained for 30 minutes, immediately cooling the container, It returned to room temperature.

  Thereafter, the reaction solution was taken out from the cavity and analyzed. For analysis of the reaction solution, the supernatant obtained by centrifuging the reaction solution was collected, glucose and xylose were quantified with a biosensor (manufactured by Oji Scientific), and the glucose saccharification rate and the xylose saccharification rate were calculated. In addition, as a comparative example, the same solid acid catalyst as used in the examples was used, and microwave treatment was not performed, but treatment was performed for the same time in an oil bath at the same temperature condition, and glucose and xylose in the reaction solution were quantified. Similarly, the saccharification rate was calculated. The calculation formula was as follows. The results are shown in FIGS.

Glucose saccharification rate = mass glucose in reaction solution after treatment / cellulose mass of starting material × 100
Xylose saccharification rate = mass of xylose in the reaction solution after treatment / mass of hemicellulose as starting material × 100

  In addition, cedar powder was made into the powder of the said average particle diameter by the grinding | pulverization process for a maximum of 30 minutes using a vibration mill. The composition of the cedar powder was performed according to the description of the Van Soest method, Proc. Nutr. Soc., 32, 123, 1973. The composition was calculated excluding moisture and by-product extracts. The analysis results of the composition are shown in Table 1.

  As shown in FIG. 1, when heated by microwave irradiation in the presence of a solid acid catalyst, the xylose saccharification rate exhibits a maximum (about 40%) at about 160 ° C., and the glucose saccharification rate increases with temperature. It became about 20% at ° C. On the other hand, as shown in FIG. 2, in the comparative example by oil bath heating, xylose had a saccharification rate of about 35% at 190 ° C., but at 160 ° C., the saccharification rate was just over 20%. Moreover, the glucose saccharification rate stopped at a level exceeding 10% for the first time at 190 ° C. That is, when compared at 160 ° C., the saccharification rate of xylose according to Example 1 is about twice that of the comparative example, and according to Example 1, it can be seen that saccharification treatment can be performed at a temperature 30 ° C. lower than that of the comparative example. It was.

  In this example, 0.03 g of eucalyptus fine powder (average particle size of about 200 μm) and 0.03 g of eucalyptus coarse powder (average particle size of about 200 μm) were used as lignocellulose-based real biomass, respectively, and the reaction temperature was set to 160 ° C. Except for varying the reaction time, the same operation as in Example 1 was performed to obtain each reaction solution, and glucose and xylose were quantified to calculate the glucose saccharification rate and the xylose saccharification rate. The effect was investigated. In addition, as a comparative example, the same solid acid catalyst as in the example was used, and microwave treatment was not performed, but the oil bath was used for the same time under the same temperature condition to determine glucose and xylose in the reaction solution. The saccharification rate was calculated in the same manner as in 1. The results are shown in FIG. 3 for the results of microwave irradiation and FIG. 4 for the results of the oil bath. The eucalyptus powder used was subjected to composition analysis in the same manner as in Example 1. The results are also shown in Table 1.

  As shown in FIG. 3, according to saccharification by microwave irradiation in the presence of a solid acid catalyst, there was no significant difference in the saccharification rate of glucose and saccharification rate of eucalyptus fine powder and eucalyptus crude powder. It was found that at 160 ° C., saccharification of xylose was promoted and showed a good saccharification rate, and the reaction time was preferably within 60 minutes, more preferably within 50 minutes. Moreover, as shown in FIG. 4, in the comparative example by oil bath heating, although there is no big difference between fine powder and coarse powder, the xylose saccharification rate remained at about 40% even after 60 minutes of reaction. Moreover, when compared with reaction time 30 minutes, it turned out that the saccharification rate to xylose by microwave irradiation reaches 2.5 to 3 times.

  In this example, 0.3 g of bagasse 1 fine powder (average particle size of about 200 μm) and 0.3 g of solid acid catalyst (graphite oxide powder) were used, and the reaction temperatures were 100 ° C., 120 ° C., 140 ° C., 160 ° C. and A reaction solution was obtained in the same manner as in Example 1 except that the temperature was 190 ° C., and glucose and xylose were quantified to calculate a glucose saccharification rate and a xylose saccharification rate. The results are shown in FIG. The bagasse 1 fine powder used was subjected to composition analysis in the same manner as in Example 1. The results are also shown in Table 1.

  As shown in FIG. 5, the saccharification rate of xylose is highest at a temperature of 130 ° C. or higher and 160 ° C. or lower, more specifically, 135 ° C. or higher and 155 ° C. or lower, more specifically 135 ° C. or higher and 145 ° C. or lower. The value (60%) was exhibited. On the other hand, the glucose saccharification rate increased at 130 ° C., and became substantially constant (30%) at 140 ° C. or higher. From the above, it was found that the above temperature range is a preferable reaction temperature for this type of powder, and as a result, a high saccharification rate of 60% was obtained with respect to the xylose saccharification rate.

In this example, 0.3 g of bagasse 2 coarse powder (average particle size 2 mm or less) and 0.3 g of bagasse 2 fine powder (average particle size 100 μm), 0.3 g of solid acid catalyst (graphene having —SO ₃ H group) Except that the reaction temperature is 140 ° C., 160 ° C. and 190 ° C., and the reaction solution is obtained in the same manner as in Example 1, and glucose and xylose are quantified. Calculated. The results are shown in FIG. The used bagasse 2 fine powder and the bagasse 2 coarse powder were subjected to composition analysis in the same manner as in Example 1. The results are also shown in Table 1.

  As shown in FIG. 6, regarding the xylose saccharification rate, no significant difference was observed between the bagasse 2 fine powder and the bagasse 2 coarse powder. Moreover, regarding the glucose saccharification rate, it was found that the bagasse 2 coarse powder tends to decrease the glucose saccharification rate as the reaction temperature increases. Further, regarding the reaction temperature, it was found that 150 ° C. or more and 170 ° C. or less exhibited a stable saccharification rate for both the glucose saccharification rate and the xylose saccharification rate, and each showed a maximum value at 155 ° C. or more and 165 ° C. or less. From the above, it was found that by adopting a reaction temperature in the above range, a glucose saccharification rate of 70% and a xylose saccharification rate of 20% can be obtained even with a coarse powder regardless of the average particle diameter of the powder. Bagasse 2 is significantly different from bagasse 1 in its saccharification form, but even in bagasse, cellulose is preferentially saccharified into glucose depending on the site (stem, leaf) and its ratio. It is inferred that this is because there are cases where hemicellulose is preferentially saccharified to xylose, but this does not restrict the present invention.

Claims (11)

A method for producing sugar or a derivative thereof from lignocellulosic real biomass,
A process comprising: bringing a solid acid catalyst and the lignocellulosic real biomass into contact with each other under microwave irradiation to decompose and saccharify the lignocellulosic real biomass.   The manufacturing method of Claim 1 whose average particle diameter of the said lignocellulose-type real biomass is 10 micrometers or more and 10 mm or less.   The said saccharification process is a manufacturing method of Claim 1 or 2 including the process which makes the said solid acid catalyst and the said lignocellulosic real biomass contact at the temperature of 130 degreeC or more and 200 degrees C or less. The lignocellulosic real biomass is a herbaceous lignocellulosic real biomass,
The said saccharification process is a manufacturing method in any one of Claims 1-3 including the process which the said lignocellulosic real biomass and the said solid acid catalyst are made to contact at the temperature of 130 degreeC or more and 160 degrees C or less. The lignocellulosic real biomass is a woody lignocellulosic real biomass,
The said saccharification process is a manufacturing method in any one of Claims 1-3 including the process which the said lignocellulose-type real biomass and the said solid acid catalyst are made to contact at the temperature of 150 to 170 degreeC.   The said solid acid catalyst is a manufacturing method in any one of Claims 1-5 which is a solid which has a Bronsted acid point.   The manufacturing method according to claim 1, wherein the solid acid catalyst is a graphite-based solid acid catalyst having a Bronsted acid point. The Bronsted acid sites are, -OH group is -CO ₂ H group and -SO ₃ 1 kind selected from the group consisting of H group or two or more, The method according to claim 6 or 7. The solid acid catalyst is a graphene comprising graphite oxide (GO) or -SO 3 _H group, The process according to any one of claims 1 to 7.   The said saccharification process is a manufacturing method in any one of Claims 1-9 using a microwave irradiation apparatus provided with a cavity resonator as a reaction chamber. A method for producing a saccharified hemicellulose from lignocellulosic real biomass,
A method comprising a saccharification step in which lignocellulosic real biomass and a solid acid catalyst are brought into contact with each other under microwave irradiation to saccharify xylose in the lignocellulosic real biomass.

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