JP6328990B2 - Method for synthesizing hydroxymethylfurfural - Google Patents

Description

  The present invention relates to a method for producing 5-hydroxymethylfurfural (HMF). More specifically, the present invention relates to a method for efficiently producing HMF using woody biomass as a direct raw material. In the present invention, cellulose and hemicellulose contained in the woody biomass are saccharified into glucose and fructose from a woody biomass material containing cellulose, glucose, and fructose by subjecting the raw material to treatment using high-temperature and high-pressure water containing alcohol or the like. At the same time as it is decomposed, it provides a new technology for causing a dehydration reaction and stably synthesizing HMF.

  Conventionally, when cellulose or the like contained in biomass is treated under hydrothermal conditions or the like, many compounds mainly having hydrocarbons having 1 to 6 carbon atoms as a basic skeleton are obtained. Among the compounds, it is known that HMF mainly has 6 carbon atoms and can be obtained via the compound shown in Chemical Formula 1 (HMF production route).

  The following points can be cited as reasons why HMF attracts attention in recent years. It is one of the compounds that can be easily obtained from biomass without using petrochemical resources, and it has been reported by recent research that various physiological activities can be seen, and for various manufacturers aiming for environmentally friendly manufacturing, And the utility value as various chemical raw materials, fuel modifiers, etc. has increased rapidly. In fact, by adding HMF to pharmaceuticals, functional foods, cosmetics, bath products, quasi drugs, new antiallergic agents and anti-inflammatory agents that can be manufactured with high safety can be adjusted (patents) Document 1), binder for mold making mixed with HMF (Patent Document 2), and other bioplastics, pharmaceuticals, agricultural chemicals, insecticides, antibacterial agents, fragrances, biofuels, etc. can be manufactured using HMF as a raw material ( Patent Document 3).

  HMF synthesis has been reported in Patent Documents 4 to 8, Non-Patent Documents 1 to 4 and the like using various characteristic methods. However, at the present time, the production method of HMF is synthesized by synthesizing furfural by hydroxymethylation with formaldehyde, and no HMF production route is used. The reason is that it can be easily obtained by dehydration from fructose, but fructose is expensive and the yield from glucose is low.

  In order to solve this problem, various techniques have been developed in the synthesis of glucose to HMF. The methods are roughly classified into two methods, ie, a method by improving the solvent and a method by improving the acid catalyst. For improving the solvent, many techniques using an ionic liquid have been reported. That is, a salt that is liquid at room temperature is used as a solvent, and an acid catalyst such as sulfuric acid or Cr is used there (Non-Patent Document 1). However, when fructose is used as a raw material, butylmethylimidazolium chloride is used as a medium, sulfuric acid is used as an acid catalyst, and the reaction takes place at 120 ° C for 30 minutes. As a result, the yield is 11% (Non-Patent Document 2). Therefore, the yield from glucose is improved to 91% by adding chromium chloride to the catalyst. However, when the raw material is cellulose, 0% and HMF are not generated (Non-patent Document 3). Therefore, the yield of 53% is obtained by further adding hydrochloric acid to the catalyst (Non-patent Document 4).

  When an ionic liquid is used, the ionic liquid itself is a special solvent, and the price is significantly higher than that of a normal solvent. Further, since Cr is used as a catalyst, it is preferable for use in medicines using HMF as a raw material. Absent. Even in reports other than these, the yield of HMF is not high particularly when cellulose is used as a raw material.

JP 2010-248107 A JP 2013-212536 A Special table 2011-506478 gazette JP 2013-231061 A JP 2009-057345 A JP 2007-145736 A Japanese Patent Laid-Open No. 2005-200321 JP-A-2005-232116

Malgorzata E. Zakrzewska, Ewa Bogel-Lukasik, and Rafal Bolgel-Lukasik, Ionic Liquid-Mediated Formation of 5-Hydroxymethylfurfural-A Promising Biomass-Derived Building Block-, Chemical Review, 2011, 111, p.397-417 C. Sievers, I. Musin, T. Marzialetti, M. B. Valenzuela-Olarte, P. K. Agrawal, C. W. Jones, ChemSUSChem, 2009, 2, p.665 S. Lima, P. Neves, M. M. Antunes, M. Pillinger, N. Ignatyev, A. A. Valente, Applyied Catalysis, A, 2009, 363, p.93 J. B. Binder, R. T. Raines, Journal of American Chemical Society, 2009, 131, p. 1979

  The present invention has been made in view of the above-described prior art, and it is efficient without using a catalyst such as Cr while using cellulose as a raw material and using environmentally friendly and easily available water as a medium. An object of the present invention is to provide a method for producing hydroxymethylfurfural.

  As a result of intensive studies to achieve the above object, the present inventors have used a solvent such as water, a relatively inexpensive organic salt such as an ammonium salt and a very small amount of organic acid as a catalyst, and high temperature and high pressure conditions. Below, when the reaction temperature was changed in a plurality of stages, the inventors succeeded in finding a method for synthesizing HMF from cellulose in a high yield with a relatively short reaction time, and completed the present invention.

The present invention has been completed based on these findings, and according to the present invention, the following inventions are provided.
[1] A method for producing 5-hydroxymethylfurfural from a raw material containing at least one of cellulose, oligosaccharides or monosaccharides or a decomposition product of the raw materials, and at least high temperature and high pressure of cellulose, oligosaccharides or monosaccharides In the presence of a quaternary ammonium salt as a catalyst, a reaction solution obtained by adding an organic acid to an aqueous solution or aqueous dispersion of a raw material containing one kind or an aqueous solution containing various sugars obtained by decomposing the raw material is reacted. The method for producing 5-hydroxymethylfurfural, comprising mixing in water or alcohol or a mixed solvent of water and alcohol and changing the reaction temperature from the reaction temperature.

[2] As the reaction solution, a reaction solution obtained by adding carboxylic acid to an aqueous solution or aqueous dispersion of a raw material containing cellulose and oligosaccharide or an aqueous solution containing various sugars obtained by decomposing the raw material, In the above [1], the reaction solution is further reacted while changing the reaction temperature in a plurality of stages including at least two stages including before and after mixing with the water or alcohol or a mixed solvent of water and alcohol. The manufacturing method of 5-hydroxymethyl furfural of description.

[3] Using a high-temperature and high-pressure microreaction device including a T-shaped micromixer, the reaction solution is rapidly mixed with the water or alcohol or a mixed solvent of water and alcohol, and the temperature is rapidly changed. The method for producing 5-hydroxymethylfurfural according to the above [1] or [2], wherein the reaction solution is reacted.

[4] The material according to any one of [1] to [3], wherein the raw material containing at least one of cellulose, oligosaccharide or monosaccharide is woody biomass such as cedar and eucalyptus. A process for producing 5-hydroxymethylfurfural.

[5] In any one of the above [1] to [4], the oligosaccharide is an oligosaccharide composed of at least one monosaccharide of glucose, galactose, mannose, and fructose. The manufacturing method of 5-hydroxymethyl furfural of description.

[6] 5 in any one of [1] to [5] above, wherein the oligosaccharide is at least one disaccharide of sucrose, lactose, maltose, trehalose, tunulose, and cellobiose. -Method for producing hydroxymethylfurfural.

[7] The above [1] to [1], wherein the monosaccharide is at least one of allose, altrose, glucose, mannose, gulose, idose, galactose, talose, psicose, fructose, sorbose, and tagatose [6] The method for producing 5-hydroxymethylfurfural according to any one of [1].

[8] The alcohol is an aliphatic alcohol or aromatic alcohol having 1 to 10 carbon atoms, which is methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, phenol, benzyl The method for producing 5-hydroxymethylfurfural according to any one of [1] to [7] above, which comprises at least one of alcohol, salicyl alcohol, cuminyl alcohol, and phenethyl alcohol.

[9] The 5-hydroxymethyl according to any one of [1] to [8] above, wherein the mixed solvent is mixed under conditions of 200 to 400 ° C. and 0.1 to 50 MPa. Production method of furfural.

[10] The quaternary ammonium salt is a tetrabutylammonium salt, a trioctylmethylammonium salt, or a benzyldimethyloctadecylammonium salt, which is ammonium chloride, ammonium bromide, tetrabutylammonium iodide, tetrabutylammonium bromide, tetrabutyl. The above-mentioned [1], which is one or more salts of ammonium chloride, tetrabutylammonium fluoride, hydroxytetrabutylammonium, tetrabutylammonium hexafluorophosphate, tetrabutylammonium sulfate, and tetrabutylammonium tetrafluoroborate. ] The manufacturing method of 5-hydroxymethyl furfural of any one of [9].

[11] The method for producing 5-hydroxymethylfurfural according to any one of [1] to [10], wherein the organic acid is a carboxylic acid.

[12] The 5-hydroxymethylfurfural of [11] above, wherein the carboxylic acid is at least one of formic acid, acetic acid, trichloroacetic acid, trifluoroacetic acid, propionic acid, and oxalic acid Production method.

  Biomass containing not only saccharides such as glucose dissolved in water but also cellulose that does not dissolve in water such as pulp can be used as a raw material. Generally, it is one of the impurities obtained by hydrothermal decomposition of saccharides, and there is almost no precipitate due to water-insoluble humic compounds. Furthermore, since the hydroxyl group of the produced HMF forms an ether bond with the alcohol or the aldehyde group is protected by forming an acetal, the amount of HMF is prevented from being increased. Furthermore, a salt such as a metal catalyst is not included, and an inexpensive quaternary ammonium salt can be used, and the cost is not so high. As a result, in the case of the flow type or percolate type, the effect of increasing the selectivity and yield of HMF is obtained while the reaction time (residence time) itself is as short as 10 minutes or less.

1 is a schematic diagram of a reaction apparatus used in Example 1. FIG. The weight yield of HMF with respect to the reaction time in Example 1 is shown. The selectivity of HMF with respect to the reaction time in Example 2 is shown. FIG. 3 is a schematic view of a reaction apparatus used in Example 2. The weight yield of HMF with respect to the reaction time in Example 2 is shown. The yield of HMF with respect to the water / ethanol concentration in Example 3 is shown. The yield of HMF with respect to the catalyst concentration in Example 4 is shown. The yield of HMF with respect to various catalysts in Example 5 is shown. The yield of HMF with respect to the reaction pressure in Example 6 is shown.

  The present invention reacts by adding an organic acid to an aqueous solution or aqueous dispersion of a raw material containing at least one of cellulose, oligosaccharides or monosaccharides or an aqueous solution containing various sugars obtained by decomposing the raw materials at high temperature and high pressure. The reaction solution is mixed with water or alcohol or a mixed solvent of water and alcohol in the presence of a quaternary ammonium salt as a catalyst, and the reaction temperature of the reaction solution is changed at a temperature. This is a method for producing 5-hydroxymethylfurfural.

  In the present invention, the raw material may be woody biomass containing cellulose, glucose, or fructose, or a herbaceous biomass raw material. Woody biomass is mainly composed of cellulose and contains hemicellulose and lignin. Biomass includes monosaccharides, disaccharides, trisaccharides, tetrasaccharides, oligosaccharides, and polysaccharides as saccharides. Disaccharides consisting of aldoses belonging to hexose as monosaccharides (allose, altrose, glucose, mannose, gulose, idose, galactose, talose), ketohexoses (psicose, fructose, sorbose, tagatose), hexose (sucrose, (Lactulose, lactose, maltose, trehalose, cellobiose, etc.), as well as trisaccharides, tetrasaccharides, oligosaccharides, and other polysaccharides including cellulose. Moreover, these components do not need to be water-soluble.

  In the present invention, it is preferable that the raw material containing at least one of cellulose, oligosaccharides or monosaccharides is biomass derived from wood such as cedar and eucalyptus, that is, woody biomass is used as a raw material.

  The oligosaccharide is an oligosaccharide composed of at least one monosaccharide of glucose, galactose, mannose and fructose.

  The oligosaccharide is at least one disaccharide of sucrose, lactose, maltose, trehalose, tunulose, and cellobiose.

  The monosaccharide is at least one of allose, altrose, glucose, mannose, gulose, idose, galactose, talose, psicose, fructose, sorbose, and tagatose.

  In the present invention, as the reaction solution, an organic acid is added to an aqueous solution or aqueous dispersion of a raw material containing at least one of cellulose and oligosaccharides or monosaccharides or an aqueous solution containing various sugars obtained by decomposing the raw material. A reaction solution obtained by reacting at high temperature and high pressure is used. More preferably, the reaction solution is further reacted while changing the reaction temperature in a plurality of stages including at least two stages including before and after mixing with water or alcohol or a mixed solvent of water and alcohol.

  The reaction temperature can be changed in a plurality of stages of the two or more stages. The reaction temperature is changed to at least two stages before and after the reaction liquid is mixed with water or alcohol or a mixed solvent of water and alcohol. It means to make it. The first first step is a process of saccharifying cellulose by acid saccharification and extraction.

  The next second stage is a stage in which saccharified sugars are rearranged and dehydrated with a reaction solvent and a catalyst to synthesize HMF. At this time, the reaction is preferably carried out at a higher reaction temperature than in the first stage. In particular, unless the temperature is raised rapidly, dehydration of saccharides, retroaldol reaction, and the like are caused to generate a large amount of impurities. Therefore, it is more preferable to cause the reaction to occur at a predetermined temperature in a short time using a micromixer or the like.

  The reaction method in the present invention can be carried out by any of batch, flow and percolate methods as long as the dehydration reaction can be performed simultaneously with the saccharification / decomposition of the raw material. Of these, the flow type is preferred because of its good reaction and processing efficiency.

  In the present invention, high temperature and high pressure generally refers to water in a supercritical state or a subcritical state if it is high temperature and high pressure water. The supercritical state of water means a state where the boundary line between the liquid and the gas disappears beyond the critical point of water (critical temperature Tc = 374 degrees, critical pressure Pc = 22.1 MPa). The subcritical state refers to a state in which a liquid and a gas coexist in a state where the temperature is 150 ° C. or higher and lower than 374 ° C. and the pressure is 0.4 MPa or higher and lower than 22.1 MPa.

  In the present invention, water or alcohol or a mixed solvent of water and alcohol is used as a reaction solvent. Especially, it is more preferable from the yield of HMF to use water or a mixed solvent of water and alcohol. In the case of a mixed solvent, the alcohol content is preferably more than 0 and 95% by mass, more preferably more than 0 and 70% by mass, and even more preferably 10 to 50% by mass.

  Examples of the water used for the reaction solvent include tap water, distilled water, ion exchange water, pure water, ultrapure water, etc. In order to improve the reaction yield, ion exchange water, distilled water, pure water, etc. It is preferable to use ultrapure water, and it is more preferable to use ion-exchanged water, distilled water, pure water, and ultrapure water in a degassed state.

  As alcohol used as a reaction solvent, C1-C10 aliphatic alcohol or aromatic alcohol can be used. Examples of aliphatic alcohols include methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, and aromatic alcohols such as phenol, benzyl alcohol, salicyl alcohol, cuminyl alcohol, and phenethyl alcohol. It can illustrate and includes any one or more of these. Of these, aliphatic alcohols such as methanol, ethanol, propanol, butanol, pentanol, and hexanol are more preferably used.

  In practice, the reaction temperature can be in the range of 100 ° C. to 500 ° C., but a suitable temperature may be selected according to the content of the reaction. Preferably, it is the range of 200 to 400 degreeC. The reaction in the saccharification / decomposition of the raw material, that is, 150 ° C. to 250 ° C. in the saccharification part and 250 ° C. to 350 ° C. in the next rearrangement / dehydration part is preferable.

  The reaction pressure is not particularly limited as long as the production method of the present invention can be carried out, but a range of 0.1 MPa to 50 MPa is preferable. The range of 5 MPa to 40 MPa is more preferable, the range of 15 MPa to 25 MPa is even more preferable, and HMF can be obtained with higher yield.

  The reaction time is not particularly limited as long as it is within a range where the production method of the present invention can be carried out. The preferred reaction time varies depending on a predetermined temperature (100 ° C. to 500 ° C.) and a predetermined pressure condition (5 MPa to 40 MPa). Usually, both the reaction in saccharification and the rearrangement / dehydration reaction are performed in the batch-type reaction method. For several hours, in the flow type reaction method, it is several tens of minutes or less, and in the percolate type reaction method, it takes about 3 hours. The reaction time in the reaction in saccharification / decomposition requires more time, and the rearrangement / dehydration reaction has a shorter reaction time. For example, in the flow-type reaction method, the reaction time itself is 10 minutes or less as saccharification / rearrangement / dehydration time.

  The saccharification reaction of the raw material of the present invention requires a reaction solvent and a catalyst. As the reaction solvent, it is preferable to use the above-mentioned water or alcohol or a mixed solvent of water and alcohol. Of these, a mixed solvent of water and alcohol (methanol, ethanol, propanol, butanol, etc.) is preferable. By using the mixed solvent, humic acid forms from sugar chains, HMF dimerization, polymerization, etc., blocking during the reaction, etc. Can be suppressed. Here, it is considered that the alcohol reacts with the hydroxyl group of HMF to form an ether or aldol, and has an effect of suppressing the polymerization of HMF.

  As the catalyst, an acid catalyst can be used. For example, organic acids such as formic acid, acetic acid, trichloroacetic acid, trifluoroacetic acid, propionic acid, oxalic acid, and sulfonic acid, and inorganic acids can be exemplified. Of these, formic acid, acetic acid, trichloroacetic acid, trifluoroacetic acid, propionic acid, and oxalic acid are preferably used. The acid catalyst concentration is preferably 1 μM to 1 M with respect to the raw material. More preferably, it is 1 mM-1M.

  The next stage reaction is a stage in which HMF is synthesized by rearrangement and dehydration reaction between a reaction solvent and a catalyst. As the reaction solvent, it is preferable to use the above-mentioned water or alcohol or a mixed solvent of water and alcohol. Among these, it is more preferable to use a mixed solvent of water and alcohol.

  An organic salt is preferably used as a catalyst for the rearrangement / dehydration reaction. Of these, quaternary ammonium salts such as tetrabutylammonium bromide and quaternary alkyl ammonium salts are more preferred. Hereinafter, these are referred to as quaternary ammonium salts. In addition, when the reaction solvent is a mixed solvent of water and alcohol, it is generally considered that salts belonging to the class of phase transfer catalysts are effective.

  The quaternary ammonium salt is a tetrabutylammonium salt, a trioctylmethylammonium salt, or a benzyldimethyloctadecylammonium salt, and is ammonium chloride, ammonium bromide, tetrabutylammonium iodide, tetrabutylammonium bromide, tetrabutylammonium chloride, Examples of the salt include one or more of tetrabutylammonium fluoride, hydroxytetrabutylammonium, tetrabutylammonium hexafluorophosphate, tetrabutylammonium sulfate, and tetrabutylammonium tetrafluoroborate.

  In the step of synthesizing HMF by rearrangement and dehydration reaction, a combination of using a mixed solvent of water and alcohol as a reaction solvent and a catalyst of a quaternary ammonium salt as a catalyst is more preferable, and HMF can be obtained with higher yield. it can.

  The micromixer and microreactor that can be used in the present invention are not particularly limited as long as they can be generally recognized as micromixers and microreactors in the technical field using high-temperature and high-pressure water.

  The micromixer is, for example, a mixer that mixes two or more fluids introduced through a plurality of pipes to generate a mixed fluid, and introduces the first fluid or the mixed fluid after the first fluid and the second fluid. A connecting pipe for derivation, the fluid after the second fluid is introduced through the space formed on the outer periphery of the connecting pipe, and the first fluid is a space provided at the tip of the connecting pipe of the first fluid; This may refer to a micro-mixing device that at least satisfies that it has a structure that mixes the fluid after the second fluid with the fluid after the second fluid, and exemplifies the micro-mixing device disclosed in Japanese Patent Application Laid-Open No. 2013-039503 Can do.

  Moreover, a microreactor usually refers to a reaction device of a very small size, and can be exemplified by a microreactor disclosed in JP2011-224480A.

  The material of the micromixer or microreactor is not particularly limited as long as it is resistant to high temperatures and pressures. For example, Inconel 625 (Ni alloy), Hasteroy (Ni alloy), SUS316, SUS306, SUS304 (stainless steel), Ti, W, etc. Is exemplified. In addition, a resin or the like can be used as long as the material has heat resistance and pressure resistance, and is not particularly limited.

  In the present invention, for example, a high-temperature and high-pressure micromixer can be used for the reaction. As a more specific example, the high-temperature and high-pressure microreaction system shown in FIG. 1 can be preferably used. In addition, any system having the same effect can be used in the same manner. The microreaction system includes a mixing means for mixing high-temperature and high-pressure water and a raw material aqueous solution, a reaction section composed of a reaction tube, an oven facility for storing these, and a temperature condition for the reaction liquid to be controlled to a predetermined temperature. A thermocouple and a reaction tube are provided with a cooler (heat exchanger) for cooling a reaction solution reacted under high-temperature and high-pressure water conditions to a predetermined temperature, a back pressure valve for releasing pressure after cooling, and the like.

  The reaction is not particularly limited as long as the production method of the present invention can be carried out, but the reaction is made of, for example, Inconel 625 or SUS316, and has an outer diameter of 1/16 inch, an inner diameter of 0.5 mm, and a length of 11 m. A tube-type reaction tube can be used. In this case, the outer diameter, inner diameter, length, etc. of the reaction tube can be designed as appropriate for its implementation, and the conditions for the material, outer diameter, inner diameter, length of the reaction tube can be set as appropriate. it can.

  The present invention uses a micro reaction device for high temperature and high pressure including a T-shaped micromixer to rapidly mix the reaction solution into the water or alcohol or a mixed solvent of water and alcohol, and rapidly increase the temperature. The reaction solution can be reacted by changing.

  In the present invention, the yield of HMF is expressed as a percentage of the molar amount of HMF converted from the concentration of HMF in the obtained sample with respect to the number of moles of cellulose contained in the wood flour converted into the amount of glucose. The conversion rate of cellulose is the percentage of the amount of cellulose reacted with respect to the amount of cellulose contained in the wood chip, and the selectivity of HMF is the percentage of the yield of HMF with respect to the conversion rate.

  Next, the present invention will be specifically described based on examples and comparative examples, but the present invention is not limited to the following examples.

[Example 1]
The reaction was performed using an apparatus as shown in FIG. The reactor was a reactor 1 temperature controlled by a heater (SUS316 inner diameter 0.9 cm × length 15 cm (volume 9.53 cm ³ ), and a reactor 2 temperature controlled by a heater (reaction tube length (SUS316 inner diameter 0). 1 cm × length 500 cm (capacity 3.92 cm ³ )), and a device comprising a cooler and a back pressure valve was used, and reactor 1 was filled with unrefined pulp (0.9245 g) and 0.1 μm using a pump. % Formic acid aqueous solution was allowed to flow at 15 MPa, 225 ° C. and 0.5 mL / min, and only the cellulose component contained in the unpurified pulp was introduced into the reactor 2 while performing acid saccharification and extraction. A butylammonium bromide solution (ethanol: water = 1: 1) is heated to 280 ° C. with a heater under the condition of 15 MPa, and the saccharified water of the previous pulp with a T-shaped micromixer The mixture was mixed with the liquid, and the temperature of the mixed solution was rapidly raised to 270 ° C., and then reacted as it was at 270 ° C. in the reactor 2. Acid saccharification + extraction time (retention time) in the reactor 1 at this time Is 1.90 seconds, and the reaction time (residence time) in the reactor 2 is 0.79 seconds, which is a total of 2.7 seconds. The pressure was lowered to obtain a 5-hydroxyfurfural-containing aqueous solution.

  The obtained HMF aqueous solution was sampled every 20 minutes (100 mL), and the content of HMF contained in each sample was immediately analyzed by liquid chromatography (input conditions). The weight yield of the obtained HMF was 71.6% after 240 minutes (FIG. 2, Table 1), and there was almost no residue of unrefined pulp in the reactor 1, and almost 100% was converted. Moreover, the selectivity of each sample was 71.5%-100% (Table 1).

[Example 2]
Under the same conditions as in Example 1, a T-shaped micromixer was installed in the reactor 2, the reaction tube length 2 was kept as it was, the reaction tube length 1 was set to 100 cm, and the catalyst temperature was the same as that of the reactor 2 ( The reaction was carried out at 270 ° C. (FIG. 4). In the T-shaped micromixer, the temperature immediately after mixing drops to about 250 ° C., and then becomes 270 ° C. while staying in the reaction tube 2. As a result, the final weight yield of HMF was 48.3% (FIG. 5) after 240 minutes, and the selectivity in each sample was 59.9% to 100% (FIG. 3).

[Example 3]
Using the same reactor as in Example 2, the ratio of ethanol to water in the catalyst (tetrabutylammonium bromide) solution was examined using glucose as a raw material. Each ethanol ratio was examined under the condition of 0% (water only) to 100% (ethanol only), and a change in the yield of HMF was observed (FIG. 6). The reaction tube length 2 was examined in two ways of 500 cm and 300 cm. As a result, at 500 cm, the maximum was obtained when the ethanol concentration was 50% (HMF yield: 28.6%), and at 300 cm, the maximum was obtained at 10% to 30% (HMF yield: 26. 3%).

[Example 4]
Using the same reactor as in Example 2, the concentration of the catalyst (tetrabutylammonium bromide) was examined using glucose as a raw material. Examination was performed at concentrations of 0 to 0.3M. As a result, it was found that at 15 MPa and 500 cm, the best value (HMF yield: 33.9%) was obtained at 0.1 M (FIG. 7).

[Example 5]
Using the same reaction apparatus as in Example 2, glucose was used as a raw material, various inorganic salts were used as catalysts and dissolved in water for examination, and changes in the yield of HMF were observed (FIG. 8). As a result, the case of only water with no catalyst added was the best (HMF yield: 26.3%), and no significant effect was observed with the inorganic salt.

[Example 6]
Using the same reaction apparatus as in Example 1, glucose was used as a raw material and tetrabutylammonium bromide was used as a catalyst, and changes in the yield of HMF due to the pressure effect were observed (FIG. 9). As a result, when water: ethanol = 50: 50 as a solvent, the HMF yield is almost 100% if it is 15 MPa or more, and in the case of 60:40, it is 10 MPa and almost 100%. In the case of 100: 0 (water only), the yield was 30% even at 15 MPa.

  In the present invention, not only saccharides such as glucose dissolved in water but also biomass containing cellulose that is not soluble in water such as pulp can be used as a raw material. In the synthesis method of the present invention, it is one of impurities generally obtained by hydrothermal decomposition of saccharides, and there is almost no precipitate due to a water-insoluble humic compound. Furthermore, since the hydroxyl group of the produced HMF forms an ether bond with the alcohol or the aldehyde group is protected by forming an acetal, the amount of HMF is prevented from being increased.

  Furthermore, a salt such as a metal catalyst is not included, and an inexpensive quaternary ammonium salt can be used, and the cost is not so high. As a result, in the case of the flow type or percolate type, the effect of increasing the selectivity of HMF to 71% and the yield to 72% is obtained while the reaction time (residence time) itself is as short as 10 minutes or less. .

  The present invention can use, as a raw material, a biomass containing cellulose that is not soluble in water such as pulp as a raw material, as well as sugars such as glucose that dissolves in water, and in the synthesis method of the present invention, in order to prevent a large amount of HMF, There is little production of these impurities. Furthermore, the reaction time (residence time) itself is shorter than before, but the effect of increasing the selectivity and yield of HMF is obtained and useful.

Claims (10)

Two-stage reaction of saccharification reaction, rearrangement reaction and dehydration reaction from raw materials mainly composed of at least one of cellulose, oligosaccharide or monosaccharide obtained from woody biomass such as cedar and eucalyptus A method for producing 5-hydroxymethylfurfural through a process ,
First, in the saccharification reaction, an aqueous solution or aqueous dispersion of a raw material mainly comprising at least one of cellulose, oligosaccharide or monosaccharide obtained from woody biomass such as cedar and eucalyptus , or cedar and eucalyptus In an aqueous solution containing various sugars obtained by decomposing a raw material mainly composed of at least one of cellulose, oligosaccharides or monosaccharides obtained from woody biomass ,
A reaction liquid is produced by reacting a subcritical fluid in a temperature and pressure range of 200 to 400 ° C. and 0.1 to 50 MPa to which an organic acid is added,
Next, in the rearrangement reaction / dehydration reaction, the reaction solution is mixed with water or alcohol or a mixed solvent of water and alcohol in the presence of a quaternary ammonium salt,
A method for producing 5-hydroxymethylfurfural , wherein the reaction solution and the mixed solvent are reacted at a temperature higher than the reaction temperature in the saccharification reaction of the reaction solution before and after mixing with the mixed solvent . As the reaction solution, various sugars obtained by decomposing an aqueous solution or aqueous dispersion of a raw material mainly containing at least one of cellulose, oligosaccharides or monosaccharides obtained from woody biomass such as cedar and eucalyptus In an aqueous solution containing
Using a reaction solution to which carboxylic acid is added,
The reaction liquid is further reacted in a plurality of stages including at least two stages including before and after mixing with water or alcohol or a mixed solvent of water and alcohol while changing the reaction temperature to a high temperature. The method for producing 5-hydroxymethylfurfural according to claim 1.   Using a micro reaction device for high temperature and high pressure including a T-shaped micromixer, the reaction solution is rapidly mixed with the water or alcohol or a mixed solvent of water and alcohol, and the temperature is rapidly changed. The method for producing 5-hydroxymethylfurfural according to claim 1 or 2, wherein the reaction solution is reacted. The 5-hydroxymethyl according to any one of claims 1 to 3 , wherein the oligosaccharide is an oligosaccharide composed of at least one monosaccharide of glucose, galactose, mannose, and fructose. Production method of furfural. 5. The 5-hydroxymethylfurfural of any one of claims 1 to 4 , wherein the oligosaccharide is at least one disaccharide of sucrose, lactose, maltose, trehalose, tulanose, and cellobiose. Production method. The monosaccharide, allose, altrose, glucose, mannose, gulose, idose, galactose, talose, psicose, fructose, sorbose, to any one of claims 1 to 5, characterized in that at least one or more of tagatose A process for producing 5-hydroxymethylfurfural according to item 1. The alcohol is an aliphatic alcohol or aromatic alcohol having 1 to 10 carbon atoms, which is methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, phenol, benzyl alcohol, salicyl The method for producing 5-hydroxymethylfurfural according to any one of claims 1 to 6 , comprising any one or more of alcohol, cuminyl alcohol, and phenethyl alcohol. The quaternary ammonium salt is a tetrabutylammonium salt, a trioctylmethylammonium salt, or a benzyldimethyloctadecylammonium salt, and is ammonium chloride, ammonium bromide, tetrabutylammonium iodide, tetrabutylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium fluoride, hydroxy tetrabutylammonium, tetrabutylammonium hexafluorophosphate, tetrabutylammonium, of claim 1 to 7, characterized in that any one or more salts of tetrabutylammonium tetrafluoroborate The manufacturing method of 5-hydroxymethyl furfural of any one.   The method for producing 5-hydroxymethylfurfural according to any one of claims 1 to 8, wherein the organic acid is a carboxylic acid. The method for producing 5-hydroxymethylfurfural according to claim 9 , wherein the carboxylic acid is at least one of formic acid, acetic acid, trichloroacetic acid, trifluoroacetic acid, propionic acid, and oxalic acid.
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