WO2013146085A1 - Method for producing 5-hydroxymethyl furfural - Google Patents

Abstract

The present invention relates to: a method for producing 5-hydroxymethyl furfural (HMF), which comprises the steps a-c described below; and a method for producing 5-hydroxymethyl furfural oxide, which comprises the steps a-d described below. Each of the methods simply and economically produces high-purity 5-hydroxymethyl furfural or an oxide thereof from a starting sugar material. Step a: A step wherein the staring sugar material is subjected to a dehydration reaction in the presence of a reaction solvent, thereby producing HMF in the reaction solvent and obtaining a reaction solvent containing HMF. Step b: A step wherein HMF is extracted from the reaction solvent containing HMF, which has been obtained in step a, into a hydrophobic solvent, thereby obtaining a hydrophobic solvent containing HMF. Step c: A step wherein HMF is extracted from the hydrophobic solvent containing HMF, which has been obtained in step b, into water, thereby obtaining an aqueous solution containing HMF. Step d: A step wherein HMF which has been obtained in step c is oxidized.

Description

Method for producing 5-hydroxymethylfurfural

The present invention relates to a method for producing 5-hydroxymethylfurfural and its oxide.

5-Hydroxymethylfurfural (hereinafter also referred to as “HMF”) is expected as an intermediate raw material for PET substitute resins, fuels, chemicals, surfactants, cosmetics and the like as a biorefinery base material. In addition, due to the multifaceted pharmacological action such as anticoagulant action of blood, in recent years, it is expected to develop into pharmaceuticals (for example, sickle cell remedy) and functional foods.

2,5-furandicarboxylic acid (hereinafter also referred to as “FDCA”), 2,5-diformylfuran (hereinafter referred to as “DFF”), which is an oxide of 5-hydroxymethylfurfural (hereinafter also referred to as “HMF”). 2-carboxy-5-formylfuran (hereinafter also referred to as “CFF”), 5-hydroxymethyl-2-furancarboxylic acid (hereinafter also referred to as “HMFA”), 5-acetoxymethyl-2- Furan carboxylic acid (hereinafter also referred to as “AcMFA”) is a useful compound as an intermediate for fine chemicals, pharmaceuticals, and agricultural chemicals. Among these, FDCA has a high utility value as an intermediate in various fields such as monomers for resins and toner binders, pharmaceuticals, agricultural chemicals, insecticides, antibacterial agents, perfumes, and the like. DFF is attracting attention as a polymer monomer, a crosslinking agent, and the like. Similar applications are also expected for HMF oxides other than FDCA and DFF.

It is known that HMF is produced by intramolecular dehydration of a raw material containing a hexose skeleton (see, for example, Patent Document 1 and Non-Patent Documents 1 to 3). Moreover, when synthesizing HMF, it is known that many byproducts such as levulinic acid, formic acid, sugar condensate, HMF polymer, humin-like substance are generated.

In addition to these by-products, as a technique for obtaining high-purity HMF from HMF contaminants in which residual raw materials, reaction intermediates, reaction solvents and catalysts are present, for example, distillation under high vacuum conditions and a short distillation path at low temperature Methods and distillation methods in which polyethylene glycol is added are known (see, for example, Patent Documents 2 and 3).
In addition, as other techniques for obtaining high-purity HMF from HMF contaminants after the synthesis reaction, a technique for separating HMF and HMF dimer using an adsorbent and a purification method by column chromatography are known. (For example, see Patent Documents 3 to 5).

As a method for producing 5-hydroxymethylfurfural oxide, HMF is generated by dehydration reaction of a saccharide containing a hexose sugar skeleton, and then HMF is oxidized using permanganate in an alkaline environment ( Patent Document 6). As a method using oxygen as an oxidizing agent, a method of oxidizing HMF in the presence of a platinum group metal catalyst (see Patent Document 7), a method of oxidizing HMF in the presence of bromine and a metal catalyst (see Patent Document 8), A method of oxidizing HMF in an acetic acid solvent in the presence of a metal bromide catalyst (see Patent Document 9 and Non-Patent Document 4) is known.

JP-A-55-53280 US Patent Application Publication No. 2008/0200698 US Patent Application Publication No. 2011/0137052 JP 2007-277198 A U.S. Pat. No. 4,740,605 JP 2007-261990 A Japanese Patent Laid-Open No. 2-88569 JP 2011-84540 A Special table 2003-528868 gazette

The present invention relates to a method for producing 5-hydroxymethylfurfural having the following steps a to c and a method for producing 5-hydroxymethylfurfural oxide having the following steps a to d.
Step a: A step of dehydrating a sugar raw material in the presence of a reaction solvent to produce 5-hydroxymethylfurfural in the reaction solvent to obtain a reaction solvent containing 5-hydroxymethylfurfural Step b: obtained in Step a Extracting 5-hydroxymethylfurfural into a hydrophobic solvent from the obtained reaction solvent containing 5-hydroxymethylfurfural to obtain a hydrophobic solvent containing 5-hydroxymethylfurfural Step c: obtained in Step b Extracting 5-hydroxymethylfurfural into water from a hydrophobic solvent containing 5-hydroxymethylfurfural to obtain an aqueous solution containing 5-hydroxymethylfurfural Step d: 5-hydroxymethylfurfural obtained in Step c Oxidation process

The HMF purification techniques described in Patent Documents 2 to 5 have problems in productivity, such as low yields. In addition, it is necessary to dispose of the adsorbing / separating agent or a complicated regeneration process after the purification treatment, which is not environmentally friendly or economical.
In the method for producing 5-hydroxymethylfurfural oxide using permanganate described in Patent Document 6, the oxidation reaction can be performed without purifying the raw material HMF synthesized from the sugar raw material. However, since permanganate is a homogeneous catalyst and is difficult to use for recycling, there is a problem that separation operation and catalyst disposal become complicated and productivity and economy are poor.
In addition, the methods described in Patent Documents 7 to 9 and Non-Patent Document 4 can obtain 5-hydroxymethylfurfural oxide with a good yield, and the catalyst can be reused. However, since by-products generated when producing HMF from a sugar raw material cause reaction inhibition and catalyst activity reduction, a complicated purification step of HMF by high vacuum distillation or column chromatography is necessary. There is a problem in economy.
Therefore, the present invention relates to a method for producing highly pure 5-hydroxymethylfurfural and its oxide easily and economically from a sugar raw material.

The present inventors have found that the above problem can be solved by an extraction method using two or more solvents having low miscibility and an oxidation reaction.

That is, the present invention relates to a method for producing 5-hydroxymethylfurfural having the following steps a to c and a method for producing 5-hydroxymethylfurfural oxide having the following steps a to d.
Step a: A step of dehydrating a sugar raw material in the presence of a reaction solvent to produce 5-hydroxymethylfurfural in the reaction solvent to obtain a reaction solvent containing 5-hydroxymethylfurfural Step b: obtained in Step a Extracting 5-hydroxymethylfurfural into a hydrophobic solvent from the obtained reaction solvent containing 5-hydroxymethylfurfural to obtain a hydrophobic solvent containing 5-hydroxymethylfurfural Step c: obtained in Step b Extracting 5-hydroxymethylfurfural into water from a hydrophobic solvent containing 5-hydroxymethylfurfural to obtain an aqueous solution containing 5-hydroxymethylfurfural Step d: 5-hydroxymethylfurfural obtained in Step c Oxidation process

According to the present invention, high-purity HMF and its oxide can be efficiently and efficiently produced from a sugar raw material by a simple extraction operation and an oxidation reaction.

The method for producing 5-hydroxymethylfurfural of the present invention has the following a to c.
The method for producing 5-hydroxymethylfurfural oxide (hereinafter also referred to as “HMF oxide”) of the present invention includes the following steps a to d.
Step a: A step of dehydrating a sugar raw material in the presence of a reaction solvent to produce 5-hydroxymethylfurfural in the reaction solvent to obtain a reaction solvent containing 5-hydroxymethylfurfural Step b: obtained in Step a Extracting 5-hydroxymethylfurfural into a hydrophobic solvent from the obtained reaction solvent containing 5-hydroxymethylfurfural to obtain a hydrophobic solvent containing 5-hydroxymethylfurfural Step c: obtained in Step b Extracting 5-hydroxymethylfurfural into water from a hydrophobic solvent containing 5-hydroxymethylfurfural to obtain an aqueous solution containing 5-hydroxymethylfurfural Step d: 5-hydroxymethylfurfural obtained in Step c Oxidation process

The reason why high-purity HMF can be produced by the production method of the present invention is not clear, but in step b, substances having a higher polarity than HMF (sugar, sugar condensate, acid, catalyst, etc.) are removed, and step c Thus, it is presumed that impurities generated during the synthesis reaction of HMF from the sugar raw material are efficiently removed by removing substances (HMF polymer, humin-like substance, etc.) having a lower polarity than HMF.
The reason why HMF oxide can be produced efficiently and with high productivity by the production method of the present invention is not clear, but an intermediate raw material in which HMF and impurities are efficiently separated can be obtained through steps a to c. Therefore, it is estimated that this is because an oxidation reaction with a good yield can be performed.

<Step a>
Step a in the production method of the present invention is a step of obtaining a reaction solvent containing HMF by dehydrating a sugar raw material in the presence of the reaction solvent to produce HMF in the reaction solvent.

(Reaction form)
The reaction form of step a is not particularly limited, and may be a batch type, a semi-batch type, a continuous type, or a combination of these. From the viewpoint of improving productivity, semi-batch reaction and continuous reaction are preferable, and from the viewpoint of easy operation, batch reaction is preferable.

(Sugar raw material)
The sugar raw material used in step a may be naturally derived or artificially synthesized, or a mixture of two or more of them. Specific examples of the sugar raw material include one or more saccharides selected from the group consisting of monosaccharides, disaccharides, oligosaccharides, and polysaccharides.
Examples of the monosaccharide include one or more selected from the group consisting of fructose, glucose, galactose, mannose, and sorbose. Examples of the disaccharide include one or more selected from the group consisting of sucrose, maltose, cellobiose and lactose. The oligosaccharide is one or more selected from the group consisting of any monosaccharide combination, and the polysaccharide is any one selected from the group consisting of any monosaccharide combination, starch, cellulose and inulin. Or 2 or more types are mentioned.
The sugar raw material is selected from the group consisting of a sugar solution derived from starch, sugarcane, sugar beet, soybean, etc., which is a mixture containing the saccharide, and a purified intermediate and a purified byproduct obtained from the sugar solution. One or two species selected from the group consisting of purified sugar, crude sugar, molasses, invert sugar, and isomerized sugar obtained from a sugar solution derived from a seed or two or more kinds, for example, starch, sugarcane, sugar beet, soybean, etc. The above can be used.

The sugar raw material used in step a is preferably a sugar raw material containing fructose from the viewpoint of economically and efficiently producing HMF and its oxide.
Examples of the sugar raw material containing fructose include, for example, fructose, a mixture of fructose and an arbitrary monosaccharide, a disaccharide combining fructose and an arbitrary monosaccharide, an oligosaccharide combining fructose and an arbitrary monosaccharide, and fructose. A high-fructose corn syrup, its refined intermediate, and its by-products; a sugar solution derived from soybean sugar, sugarcane and sugar beet, and a refined sugar and a crude sugar obtained from the sugar solution , Waste molasses, and invert sugar; and one or more selected from the group consisting of inulin. Examples of monosaccharides that can be combined with fructose include one or more selected from the group consisting of glucose, galactose, mannose, and sorbose. Among these, from the viewpoint of economically and efficiently producing HMF and its oxide, one or more selected from the group consisting of glucose, mannose, and galactose are preferable, and glucose is more preferable.
As a sugar raw material containing fructose, it is obtained from a sugar solution derived from a mixture of glucose and fructose, fructose, sucrose, inulin, sugarcane and sugar beet, from the viewpoint of economically and efficiently producing HMF and its oxide. One or more kinds selected from the group consisting of purified sugar, crude sugar and molasses are more preferred.

When using a sugar raw material that does not contain fructose or has a low fructose content, pre-treatment may be performed in advance to increase the fructose content. Specific examples of the pretreatment include isomerization treatment, hydrolysis treatment, acid treatment, base treatment and the like with enzymes and chemical substances. Among these, from the viewpoint of productivity and economy, pretreatment using an enzyme is preferred, and pretreatment including isomerase treatment is preferred. Further, when the pretreatment is not performed, the sugar raw material may be treated in the step a in the same manner as the pretreatment to generate fructose in the reaction system.

In the step a, the concentration of the sugar raw material in the reaction solvent is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and more preferably 0.5% by mass or more from the viewpoint of achieving both improvement in reaction rate and improvement in HMF yield. Preferably it is 1 mass% or more, More preferably, it is 3 mass% or more, Preferably it is 80 mass% or less, More preferably, it is 70 mass% or less, More preferably, it is 60 mass% or less, More preferably, it is 50 mass% or less.

(Dehydration reaction)
The synthesis reaction of HMF from the sugar raw material in step a is a three-molecule dehydration reaction from hexose, mainly fructose. This dehydration reaction is preferably performed using a reaction solvent and a catalyst from the viewpoint of improving the productivity of HMF and improving the purity of the obtained HMF.

(Reaction solvent)
The reaction solvent used in step a is preferably a polar solvent from the viewpoint of improving the productivity of HMF and its oxide and improving the purity of the obtained HMF. Preferred polar solvents include one or more selected from the group consisting of water, highly polar aprotic organic solvents, and ionic liquids.
As water, 1 type, or 2 or more types chosen from the group which consists of distilled water, ion-exchange water, and pure water is mentioned.
Examples of the highly polar aprotic organic solvent include dimethyl sulfoxide, sulfolane, dimethylacetamide, N, N-dimethylformamide, N-methylmorpholine, N-methyl-2-pyrrolidinone, 1,3-dimethyl-2-imidazo. Examples thereof include one or more selected from the group consisting of lydinone, hexamethylphosphoric triamide, tetramethylurea, acetonitrile, ethylene glycol dimethyl ether, acetone, methyl ethyl ketone, 1,4-dioxane and tetrahydrofuran. The high polar aprotic organic solvent preferably has a water-octanol distribution coefficient (Log P value) of less than 0.3, more preferably 0.2 or less, and 0.1 or less. More preferred is 0 or less.
Examples of the ionic liquid include imidazolium salts such as 1-ethyl-3-methylimidazolium chloride; pyrrolidinium salts such as 1-butyl-1-methylpyrrolidinium bromide; 1-butyl-1-methylpiperidi Piperidinium salts such as nitrotriflate; pyridinium salts such as 1-butylpyridinium tetrafluoroborate; ammonium salts such as tetrabutylammonium chloride; phosphonium salts such as tetrabutylammonium bromide; sulfonium salts such as triethylsulfonium bis (trifluoromethanesulfonyl) imide 1 type (s) or 2 or more types chosen from the group which consists of are mentioned.
Of these, water, dimethyl sulfoxide, dimethylacetamide, N, N-dimethylformamide, N-methyl-2-pyrrolidinone, from the viewpoint of improving the productivity of HMF and its oxides, improving the purity of HMF, operability and economy, One or more kinds selected from the group consisting of acetone, methyl ethyl ketone, sulfolane, imidazolium salts, pyridinium salts, and tetrahydrofuran are more preferable, and water, dimethyl sulfoxide, N-methyl-2-pyrrolidinone, dimethylacetamide, acetone, imidazo One or more selected from the group consisting of a lithium salt and tetrahydrofuran is more preferable, and one or more selected from the group consisting of water, dimethyl sulfoxide, acetone, imidazolium salts, and tetrahydrofuran is more preferable.

(Hydrophobic solvent)
In the present invention, from the viewpoint of improving the productivity of HMF and its oxide, suppressing the formation of by-products, and improving the purity of HMF, when water is used as the reaction solvent, step a and step b described later are simultaneously performed. Preferably it is done. Specifically, by performing the dehydration reaction in step a in the presence of water and a hydrophobic solvent, while generating HMF in water, at least a part of the generated HMF is transferred into the hydrophobic solvent, It is preferable to obtain water containing HMF and a hydrophobic solvent containing HMF.

The hydrophobic solvent used when performing step a and step b at the same time is miscible with water from the viewpoint of improving the productivity of HMF and its oxides, suppressing the formation of by-products, and improving the purity of HMF. It is preferable that the aqueous phase and the hydrophobic solvent phase are phase-separated. Specifically, the water-octanol partition coefficient (Log P value) is preferably 0.4 or more, more preferably 0.5 or more, preferably 10 or less, more preferably 7 or less, and even more preferably 5 or less. is there.
Furthermore, as a hydrophobic solvent used when performing step a and step b at the same time, productivity of HMF and its oxide is improved, formation of by-products is suppressed, purity of HMF is improved, reaction temperature and catalyst From the viewpoint of stability to the above, preferably, one kind selected from the group consisting of aliphatic ketones, aliphatic alcohols, aliphatic esters, aliphatic ethers, aromatic hydrocarbons and halogenated hydrocarbons or 2 or more, more preferably methyl isobutyl ketone (hereinafter also referred to as “MIBK”), cyclohexanone, n-butanol, 2-butanol, n-amyl alcohol, cyclohexanol, dichloromethane, trichloromethane, toluene, xylene, benzene , Cumene, benzonitrile, chlorobenzene, dichloroethane, isophorone, ethyl acetate, One or more selected from the group consisting of propyl acid and butyl acetate, more preferably one selected from the group consisting of methyl isobutyl ketone, cyclohexanone, n-butanol, 2-butanol, toluene, and isophorone Or they are 2 or more types, More preferably, they are 1 type, or 2 or more types chosen from the group which consists of methyl isobutyl ketone, isophorone, and toluene.

The amount of the hydrophobic solvent used when performing step a and step b at the same time is preferably relative to water used as a reaction solvent from the viewpoints of economy, suppression of HMF by-product formation, and reduction of equipment load. Is 0.01% by mass or more, more preferably 0.1% by mass or more, further preferably 0.2% by mass or more, more preferably 1% by mass or more, still more preferably 2% by mass or more, and further preferably 5% by mass. Or more, more preferably 10% by mass or more, preferably 100000% by mass or less, more preferably 50000% by mass or less, still more preferably 25000% by mass or less, still more preferably 10,000% by mass or less, and further preferably 7500% by mass or less. More preferably, it is 5000 mass% or less, More preferably, it is 2500 mass% or less.

(Reaction temperature)
The reaction temperature in step a is preferably 50 ° C. or higher, more preferably 60 ° C. or higher, from the viewpoint of improving the reaction rate and suppressing the production of byproducts, although it depends on the type of catalyst used, the reaction solvent and the reaction type. More preferably, it is 70 ° C. or higher, more preferably 80 ° C. or higher, more preferably 90 ° C. or higher, more preferably 100 ° C. or higher, preferably 300 ° C. or lower, more preferably 280 ° C. or lower, still more preferably 270 ° C. or lower. More preferably, it is 260 ° C. or less, more preferably 250 ° C. or less, and further preferably 240 ° C. or less.

(Reaction pressure)
The reaction pressure in step a depends on the type of catalyst used, the reaction solvent, and the reaction type, but is preferably 0.01 MPa or more, more preferably from the viewpoint of improving the reaction rate, reducing the amount of by-products generated, and reducing the equipment load. Is 0.05 MPa or more, more preferably 0.1 MPa or more, preferably 40 MPa or less, more preferably 20 MPa or less, still more preferably 15 MPa or less.

(catalyst)
In step a, the dehydration reaction is preferably performed in the presence of a catalyst from the viewpoint of improving the productivity of HMF and improving the selectivity of HMF. As the catalyst, either a homogeneous catalyst or a heterogeneous catalyst can be used, and an acid catalyst is preferred.
For example, as homogeneous catalysts, inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid and boric acid; sulfonic acids such as p-toluenesulfonic acid and xylenesulfonic acid; formic acid, acetic acid, levulinic acid, oxalic acid, fumaric acid, Examples thereof include one or more selected from the group consisting of carboxylic acids such as maleic acid and citric acid; and neutralized salts thereof.
Examples of heterogeneous catalysts include strongly acidic cation exchange resins represented by amberlist, amberlite, diamond ion, etc .; zeolite, alumina, silica-alumina, silica-magnesia, silica-titania, titania, tin- Metal oxides such as titania and niobia, clays, sulfuric acid immobilization catalysts represented by sulfated zirconia; phosphoric acid immobilization catalysts represented by phosphorylated titania; heteropoly acids, Lewis acids such as aluminum chloride and chromium chloride 1 type or 2 types or more chosen from the group which consists of metal salt which has an effect | action; and these mixtures are mentioned.

Among these, as the catalyst used in step a, from the viewpoint of improving the yield of HMF and its oxides and economical efficiency, inorganic acids, carboxylic acids, strongly acidic cation exchange resins, sulfuric acid-immobilized catalysts, and phosphoric acid One or more selected from the group consisting of immobilized catalysts are preferred, more preferably one or more selected from the group consisting of inorganic acids, carboxylic acids, and strongly acidic cation exchange resins, more preferably Is one or two selected from the group consisting of hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, boric acid, formic acid, acetic acid, levulinic acid, oxalic acid, fumaric acid, maleic acid, citric acid, and neutralized salts thereof More preferably, one or more selected from the group consisting of sulfuric acid, hydrochloric acid, phosphoric acid, formic acid, acetic acid, levulinic acid, oxalic acid, boric acid and neutralized salts thereof, more preferably sulfuric acid, hydrochloric acid Phosphoric acid, and is one or more selected from the group consisting of neutralized salt.

(Amount of catalyst used)
The amount of catalyst used in step a is the same as the sugar raw material when a homogeneous catalyst is used from the viewpoints of improving the pH of the reaction system, the productivity of HMF and its oxide, suppressing the production of by-products, and economy. It is preferable that it is 0.001 mass% or more with respect to it, More preferably, it is 0.005 mass% or more, More preferably, it is 0.01 mass% or more, More preferably, it is 0.025 mass% or more, More preferably, it is 0.05. It is preferably not less than 50% by weight, more preferably not more than 30% by weight, still more preferably not more than 20% by weight, still more preferably not more than 15% by weight, and still more preferably not more than 10% by weight. This is not the case when a heterogeneous catalyst is used, for example, when a continuous reaction using a catalyst fixed bed is performed.

(Neutralization process)
When an acid catalyst is used in step a, or when the reaction system is in an acidic state, from the viewpoint of improving the productivity of HMF and its oxides and improving the purity of HMF, the step after the completion of the reaction or the steps described later It is preferable to neutralize after completion of b, and more preferably neutralize after completion of the reaction.
Preferred neutralizing agents include basic substances such as anion exchange resins, basic zeolites, alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal carbonates, alkaline earth metal carbonates, organic amines. 1 type (s) or 2 or more types chosen from the group which consists of a kind, calcium oxide, magnesium oxide, and ammonium salt. Among these, from the viewpoint of improving productivity and economic efficiency of HMF and its oxides, a group consisting of alkali metal hydroxide, alkaline earth metal hydroxide, alkali metal carbonate, alkaline earth metal carbonate and organic amine 1 type or 2 types or more selected from are preferable, and 1 type or 2 types or more selected from the group consisting of alkali metal hydroxides and alkaline earth metal hydroxides are more preferable.

When neutralization is performed, from the viewpoint of improving the yield of HMF and improving the purity of HMF, the pH of the solution after neutralization is preferably 4 or more, more preferably 5 or more, still more preferably 6 or more, and preferably 10 or less. 9 or less is more preferable, and 8 or less is more preferable.

(Removal of insoluble matter)
In step a, insoluble matter may be generated during the reaction depending on the reaction conditions, catalyst type, catalyst amount, sugar raw material, and concentration thereof. This insoluble matter is an anhydrous sugar or sugar condensate due to intramolecular and intermolecular dehydration of sugar in the sugar raw material, HMF polymer, HMF, sugar raw material, reaction intermediate, and HMF overreaction product due to condensation polymerization between HMFs. Presumed to be humic substances produced from This insoluble matter is preferably removed by filtration or centrifugation as necessary. The removal step may be performed after step b or step c described later.

<Process b>
Step b in the method of the present invention is a step of obtaining a hydrophobic solvent containing HMF by extracting HMF into a hydrophobic solvent from the reaction solvent containing HMF obtained in the step a.
As specific examples of the extraction method in step b, a reaction solvent containing HMF and a hydrophobic solvent are mixed, and HMF is extracted into the hydrophobic solvent, or the solvent is once distilled off from the reaction solvent containing HMF. After obtaining a concentrate, a method of extracting HMF in a hydrophobic solvent by adding a solvent that can be used as the reaction solvent and a hydrophobic solvent to the concentrate, a reaction solvent containing HMF, or the concentration Examples thereof include a method in which a hydrophobic solvent and a salt or an organic solvent are added to the product to extract HMF into the hydrophobic solvent. Examples of the salt used here include one selected from the group consisting of chloride, sulfate, bromide, iodide, nitrate, and carbonate of a metal selected from, for example, sodium, potassium, calcium, and magnesium. Or 2 or more types are mentioned. Examples of the organic solvent include one or more selected from the group consisting of methanol, ethanol, and isopropanol.
When step a and step b are performed at the same time, after step a and step b are performed at the same time, the step b of extracting HMF into a hydrophobic solvent from the water containing HMF obtained in step a is further performed. Preferably it is done.

From the viewpoint of economy, reduction of equipment load, and improvement of HMF extraction efficiency, the reaction solvent containing HMF obtained in step a may be appropriately concentrated before performing step b. In this case, examples of the concentration method include concentration under reduced pressure, a method using an osmotic membrane, transpiration, freeze drying, and the like. In the case of concentration under reduced pressure, from the viewpoint of the thermal stability of HMF, it is preferably performed at 150 ° C. or lower, more preferably 120 ° C. or lower, more preferably 100 ° C. under sufficient reduced pressure conditions that can distill off the reaction solvent. ° C or lower, more preferably 80 ° C or lower.

When the reaction solvent containing HMF obtained in step a is concentrated before carrying out step b, it is added to the hydrophobic solvent used in step b from the viewpoint of improving the amount of solution and operability and improving the HMF purity. Water may be added. The water used is preferably one or more selected from the group consisting of distilled water, ion-exchanged water and pure water from the viewpoints of economic efficiency and HMF purity improvement.

(Hydrophobic solvent)
The hydrophobic solvent used in step b is low in miscibility with water from the viewpoint of improving the productivity of HMF and its oxides, suppressing the formation of by-products, and improving the purity of HMF, and is an aqueous phase-hydrophobic solvent. It is preferable that the phases are separated. In addition, from the same viewpoint, the hydrophobic solvent preferably has a water-octanol distribution coefficient (Log P value) of 0.3 or more, more preferably 0.4 or more, still more preferably 0.5 or more, More preferably, it is 10 or less.

Preferred hydrophobic solvents used in step b include aliphatic ketones, aliphatic ethers, aliphatic alcohols, aliphatic esters, lactones, aromatic hydrocarbons having a water-octanol partition coefficient of 0.3 or more. 1 type (s) or 2 or more types chosen from the group which consists of a group, aliphatic hydrocarbons, halogenated hydrocarbons, and hydrophobic ionic liquids. Among these, aliphatic ketones, aliphatic ethers, aliphatic alcohols, aliphatic esters, fatty acid amides, aromatic hydrocarbons from the viewpoint of extraction efficiency of HMF and suppression of the amount of hydrophobic solvent dissolved in water 1 type or 2 or more types selected from the group consisting of hydrocarbons, aliphatic hydrocarbons, and halogenated hydrocarbons, more preferably 3-methyl-2-butanone, methyl isobutyl ketone, diisobutyl ketone, 5- Methyl-3-heptanone, cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, isophorone, tetrahydrofuran, furfural, furfuryl alcohol, n-butanol, 2-butanol, n-amyl alcohol, isopentyl alcohol, hexyl alcohol, Chloromethane, dichloromethane, trichloromethane, Consists of trichloroethane, diethyl ether, methyl-tert-butyl ether, diisopropyl ether, toluene, xylene, benzene, cumene, dichloroethane, decane, decene, dodecane, dodecene, hexane, pentane, petroleum ether, ethyl acetate, propyl acetate, and butyl acetate One or more selected from the group, more preferably methyl isobutyl ketone, cyclohexanone, n-butanol, 2-butanol, n-amyl alcohol, dichloromethane, trichloromethane, diethyl ether, methyl-tert-butyl ether, diisopropyl ether 1 or more selected from the group consisting of toluene, dichloroethane, hexane, ethyl acetate, propyl acetate, and butyl acetate, more preferably methyl isobutyl ketone, One or more selected from the group consisting of rohexanone, 2-butanol, dichloromethane, trichloromethane, diethyl ether, diisopropyl ether, ethyl acetate, butyl acetate, toluene, dichloroethane, and hexane.

The extraction can be performed by, for example, batch extraction or countercurrent extraction. The temperature at the time of extraction is preferably 5 ° C. or higher, more preferably 10 ° C. or higher, further preferably 15 ° C. or higher, preferably 120 ° C. or lower, more preferably 100 ° C. or lower, from the viewpoint of the thermal stability of HMF. More preferably, it is 80 degrees C or less.
The amount of the hydrophobic solvent used per extraction process is not particularly limited. From the viewpoint of improving the extraction efficiency of HMF, for example, when performing a batch extraction method, the mass ratio of the reaction solvent or water (reaction solvent) Or water / hydrophobic solvent), preferably 1/100 or more, more preferably 1/50 or more, further preferably 1/20 or more, preferably 10/1 or less, more preferably 5/1 or less, Preferably it is 2/1 or less.

(Removal of insoluble matter)
In step b, insoluble matter may be generated depending on the type of sugar raw material, solvent, catalyst, and the like used. This is presumed to be humic substances produced from anhydrous sugar, sugar condensate, HMF polymer by condensation polymerization of HMF, and HMF, sugar raw material, reaction intermediate and HMF overreaction product. This insoluble matter is preferably removed by filtration, centrifugation or the like, if necessary. The removal step may be performed after step b or after step c described later.

<Process c>
Step c in the method of the present invention is a step of obtaining an aqueous solution containing HMF by extracting HMF into water from the hydrophobic solvent containing HMF obtained in the aforementioned step b.
As specific examples of the extraction method in step b, a method of extracting HMF into water by mixing a hydrophobic solvent containing HMF and water, or once distilling off the hydrophobic solvent from the hydrophobic solvent containing HMF And a method of extracting HMF into water by adding a hydrophobic solvent and water.

From the viewpoint of reducing the equipment load and improving the extraction efficiency of HMF, the hydrophobic solvent used in the extraction of step b may be distilled off after step b and before step c to concentrate HMF.
Examples of the method for concentrating HMF include vacuum concentration, a method using an osmotic membrane, and transpiration. In the case of concentration under reduced pressure, from the viewpoint of the thermal stability of HMF, it is preferably performed at 150 ° C. or lower, more preferably 120 ° C. or lower, and more preferably 120 ° C. or lower, under a sufficient reduced pressure condition capable of distilling off the hydrophobic solvent. 100 ° C. or lower, more preferably 80 ° C. or lower.

When the HMF extract obtained in step b is concentrated to obtain an HMF concentrate, and then the extraction operation in step c is performed, in addition to water, it is hydrophobic in addition to water from the viewpoint of improving the amount of solution, operability, and HMF purity. A suitable solvent may be added as appropriate. As the hydrophobic solvent used in step c, a hydrophobic solvent that can be used in step b can be used, and examples thereof include the same specific examples and preferred examples as described in step b. The hydrophobic solvent used in step c may be the same as or different from the hydrophobic solvent used in step b.

The water used in step c is one or two selected from the group consisting of distilled water, ion-exchanged water, and pure water from the viewpoints of economic efficiency, HMF purity improvement, and HMF oxide productivity. The above is preferable. In step c, from the viewpoint of improving extraction efficiency and operability during extraction and shortening the work process, one or more organic solvents may be further mixed with water. Preferred organic solvents include one or more selected from the group consisting of methanol, ethanol, propanols, butanols, acetonitrile, tetrahydrofuran, dioxanes, acetone, and methyl ethyl ketone. Among these, from the viewpoint of improving the purity of HMF, one or more selected from the group consisting of methanol, ethanol, and isopropanol is preferable, and more preferably, one or two selected from the group consisting of methanol and isopropanol. More than species, more preferably isopropanol.

The mixing ratio of water and the hydrophobic solvent containing HMF in step c is not particularly limited. From the viewpoint of improving the extraction efficiency of HMF, for example, when performing a batch type extraction method, [water / The hydrophobic solvent containing HMF] is preferably 1/100 or more, more preferably 1/50 or more, still more preferably 1/20 or more, preferably 100/1 or less, more preferably 20/1. Hereinafter, it is more preferably 10/1 or less.

After the completion of step c, the aqueous solution used for extraction may be distilled off and concentrated. Examples of the concentration method include concentration under reduced pressure, a method using an osmotic membrane, transpiration, lyophilization, and the like. In the case of concentration under reduced pressure, from the viewpoint of the thermal stability of HMF, it is preferably performed at 150 ° C. or lower, more preferably 120 ° C. or lower, more preferably 100 ° C. under a sufficient reduced pressure condition that water can be distilled off. Below, it is 80 degrees C or less more preferably. At this time, it is preferable to distill off a gas such as nitrogen from the viewpoint of the obtained HMF purity. Or it is also preferable from the viewpoint of HMF purity improvement to add and distill off the solvent which forms an azeotrope with water, for example, methanol, ethanol, isopropanol, or acetone.

<Step (c-2)>
The production method of the present invention preferably includes a step (c-2) (hereinafter sometimes referred to as “step c-2”) for further purifying HMF from the aqueous solution containing HMF obtained in step c. Preferable purification methods include, for example, one or more selected from the group consisting of dehydration, crystallization and recrystallization, solvent extraction, adsorption treatment, column chromatography, and distillation.
In the case of dehydration, for example, drying under reduced pressure or using a dehydrating agent such as sodium sulfate or molecular sieves is performed.
In the case of recrystallization, for example, it is performed by cooling to a temperature at which HMF is recrystallized.
In the case of solvent extraction, the solvent to be used is preferably one that has low miscibility with water used in step c and phase separation of the aqueous phase and the hydrophobic solvent phase.
As the preferable solvent used in the solvent extraction in step c-2, the above-mentioned hydrophobic solvent is preferable. The hydrophobic solvent preferably has a water-octanol partition coefficient (Log P value) of 0.5 or more, more preferably 1.0 or more, still more preferably 1.3 or more, and even more preferably 5 or less. 1 type, or 2 or more types selected from the group consisting of xylene and hexane. Of these, toluene is preferable from the viewpoint of improving the HMF purity.
In the case of adsorption treatment, depending on the impurities in the solution after step c and its concentration, for example, silica, activated carbon, white clay, adsorption treatment resin, ion exchange resin, or the like can be used.
Among these, from the viewpoint of the purity of the obtained HMF, one or more selected from the group consisting of dehydration, recrystallization, solvent extraction, and adsorption treatment is preferable, and from the group consisting of dehydration, recrystallization, and solvent extraction. One or more selected are more preferable, and recrystallization is more preferable.

<Process d>
Step d in the method of the present invention is a step of oxidizing the HMF obtained in step c or step c-2.
The method for oxidizing HMF is not particularly limited, but preferred methods include (1) a method of oxidizing HMF by contacting it with an oxidizing gas in an organic acid solvent in the presence of a metal catalyst and a halogen compound (hereinafter referred to as “the HMF”). (Also referred to as “oxidation method 1”), and (2) a method in which an oxidizing gas and HMF are brought into contact with each other in the presence of a catalyst containing at least one metal element selected from Groups 8 to 11 of the periodic table. (Hereinafter also referred to as “oxidation method 2”).

(Oxidation method 1)
The oxidation method 1 is a method of oxidizing HMF in contact with an oxidizing gas in an organic acid solvent in the presence of a metal catalyst and a halogen compound.

(Reaction format)
The reaction of the oxidation method 1 may be carried out by any of batch, semi-continuous and continuous methods.
The batch method is a method in which the raw material HMF and the whole amount of the catalyst are charged in a reactor in advance, an oxidizing gas is passed through the reaction solution to perform an oxidation reaction, and the reaction solution is recovered at a time after the reaction is completed.
The semi-continuous method is, for example, a method in which the entire amount of the catalyst is charged into the reactor, the oxidation reaction is performed while continuously supplying the raw material HMF and the oxidizing gas to the reactor, and the reaction liquid is recovered at once after the reaction is completed. It is.
The continuous method is a method in which an oxidation reaction is performed while continuously supplying all of the raw material HMF, the catalyst, and the oxidizing gas to the reactor, and the reaction solution is continuously recovered.
In industrial implementation, the continuous type or semi-continuous type is preferable from the viewpoint of operation efficiency.

(Organic acid solvent)
The organic acid solvent used in the oxidation method 1 is preferably one or more selected from the group consisting of acetic acid, propionic acid, and a mixed solvent of acetic acid / acetic anhydride from the viewpoint of reaction yield and solvent recovery. Is more preferable.
The amount of the organic acid solvent used is not particularly limited, but from the viewpoint of productivity, the mass ratio of [organic acid solvent / HMF] is preferably 1.0 or more, more preferably 3 or more, still more preferably 5 or more, and 30 or less. Is preferable, 20 or less is more preferable, and 15 or less is still more preferable.

(catalyst)
The metal catalyst used in the oxidation method 1 is preferably one or more selected from the group consisting of a cobalt-based catalyst and a manganese-based catalyst. The cobalt-based catalyst and the manganese-based catalyst are not particularly limited as long as they can be dissolved in the reaction solvent at the reaction temperature.
Examples of the cobalt-based catalyst include one or more selected from the group consisting of cobalt inorganic acid salts (eg, bromide, carbonate, etc.) and organic acid salts (eg, acetate, propionate, etc.). It is done. Among these, from the viewpoint of availability and economy, preferably one or more selected from the group consisting of cobalt acetate, cobalt bromide, cobalt sulfate, cobalt nitrate, cobalt carbonate, cobalt chloride, and cobalt. Yes, more preferably one or more selected from the group consisting of cobalt acetate and cobalt bromide, still more preferably cobalt acetate, and hydrates thereof may be used.
Examples of the manganese-based catalyst include one or more selected from the group consisting of inorganic salts of manganese (eg, bromide, carbonate, etc.) and organic acid salts (eg, acetate, propionate, etc.). It is done. Among these, from the viewpoint of availability and economy, preferably one or more selected from the group consisting of manganese acetate, manganese bromide, manganese sulfate, manganese nitrate, manganese carbonate, manganese chloride, and manganese. Yes, more preferably one or more selected from the group consisting of manganese acetate and manganese bromide, still more preferably manganese acetate, and hydrates thereof may be used.

The halogen compound used in the oxidation method 1 may be any halogen compound that can be dissolved in a reaction solvent at a reaction temperature and can supply a halogen ion. Examples thereof include one or more selected from the group consisting of cobalt salts, manganese salts, ammonium salts, and organic halides.
Among these, from the viewpoint of reactivity, one or two or more selected from the group consisting of bromine, sodium bromide, potassium bromide, cobalt bromide, and manganese bromide are preferable.
Cobalt bromide and manganese bromide can serve as both the cobalt catalyst and the halogen compound.

(Oxidation catalyst amount)
The amount of the metal catalyst used in the oxidation method 1 is preferably 0.1 mol% or more with respect to the raw material HMF obtained by the method including steps a to c, from the viewpoint of reactivity and the yield of HMF oxide. More preferably 0.5 mol% or more, still more preferably 1.0 mol% or more, preferably 60.0 mol% or less, more preferably 40.0 mol% or less, still more preferably 15.0 mol% or less. It is.
The amount of the cobalt-based catalyst used in the oxidation method 1 is preferably 0.1 mol% or more with respect to the raw material HMF obtained by the method including steps a to c from the viewpoint of reactivity and the yield of HMF oxide. More preferably 0.5 mol% or more, still more preferably 1.0 mol% or more, preferably 30.0 mol% or less, more preferably 20.0 mol% or less, still more preferably 15.0 mol%. It is as follows.
The amount of the manganese-based catalyst used in the oxidation method 1 is preferably 0.1 mol% or more with respect to the raw material HMF obtained by the method including steps a to c from the viewpoint of reactivity and the yield of HMF oxide. More preferably, it is 0.5 mol% or more, more preferably 1.0 mol% or more, preferably 30 mol% or less, more preferably 20.0 mol% or less.
The amount of the halogen compound used in oxidation method 1 is preferably 0.01 mol% or more with respect to the raw material HMF obtained by the method including steps a to c, from the viewpoint of reactivity and the yield of HMF oxide. More preferably, it is 0.1 mol% or more, Preferably it is 20.0 mol% or less, More preferably, it is 15.0 mol% or less, More preferably, it is 10.0 mol% or less.

(Oxidizing gas supply method, pressure, flow rate)
The oxidizing gas used in the oxidation method 1 may be oxygen, air, and a mixed gas of two or more selected from the group consisting of oxygen, air, and inert gas for dilution (nitrogen, argon, etc.).
The method for supplying the oxidizing gas is not particularly limited as long as it can be supplied to the reactor at a predetermined pressure and flow rate. The oxidizing gas may be circulated in the gas phase space or may be blown from the liquid.

A typical supply method of the oxidizing gas is a mixture of air and an inert gas for dilution (nitrogen, argon, etc.) using a known mixer, and a predetermined pressure and / or a predetermined flow rate as a mixed gas in which the oxygen concentration is controlled. This is a method of supplying to the reactor.
The higher the pressure of the oxidizing gas, the higher the reactivity, as long as the reaction solvent can maintain a liquid phase at the reaction temperature. However, if the pressure is too high, the capital investment for securing confidentiality increases, and the preparation time before and after the reaction often increases, which increases the possibility of reducing productivity. From these viewpoints, the pressure of the oxidizing gas is preferably 0.01 MPa or more, more preferably 0.1 MPa or more, preferably 10 MPa or less, more preferably 8 MPa or less, and still more preferably 5 MPa or less.
As the flow rate of the oxidizing gas increases, the reactivity increases. However, if the flow rate is too high, the capital investment for supply increases and the amount of exhaust gas increases, resulting in a decrease in economic efficiency. Accordingly, the flow rate of the oxidizing gas is preferably 1 L / min or more per 1.0 mol of charged HMF, more preferably 2 L / min or more, and preferably 20 L / min or less, and 10 L / min or less. More preferably.

(Reaction temperature)
The reaction temperature of the oxidation reaction 1 is preferably 50 ° C. or higher, more preferably 60 ° C. or higher, still more preferably 80 ° C. or higher, still more preferably 90 ° C. or higher, further preferably 100 ° C. or higher, more preferably 250 ° C. from the viewpoint of reactivity. The following is preferable, 240 ° C. or lower is more preferable, 230 ° C. or lower is further preferable, 220 ° C. or lower is further preferable, and 200 ° C. or lower is further preferable.

(Purification)
From the viewpoint of improving the purity, the HMF oxide may be purified after completion of the oxidation reaction, and can be purified by a known method such as JP-A-2001-288139. For example, when the HMF oxide is FDCA, a liquid containing water is added to the HMF oxide obtained by filtration after completion of the oxidation reaction to form a slurry, which is heated and dissolved in the presence of the hydrogenation catalyst. It can refine | purify by performing a hydrogenation process and subjecting the obtained reaction material to crystallization and solid-liquid separation. It is preferable to dry the solid obtained by solid-liquid separation after the purification step as it is to obtain a product. Furthermore, after adding water and washing | cleaning newly, the solid substance isolate | separated into solid and liquid may be dried and it may be set as a product.

(Oxidation method 2)
The oxidation method 2 is a method in which an oxidizing gas and HMF are brought into contact with each other and oxidized in the presence of a catalyst containing at least one metal element selected from Groups 8 to 11 of the periodic table.

(Oxidation catalyst)
The catalyst used in the oxidation method 2 is a catalyst containing one or more metal elements selected from the group consisting of Groups 8 to 11 of the periodic table (hereinafter also referred to as “noble metal catalyst”).
The noble metal catalyst is one or two selected from the group consisting of ruthenium, rhodium, palladium, osmium, iridium, platinum, gold, and cobalt (hereinafter also referred to as “platinum group elements”) from the viewpoint of catalytic activity. It is preferable to contain the above elements, more preferably one or more elements selected from the group consisting of palladium, gold, ruthenium and platinum, and more preferably selected from the group consisting of palladium and platinum. More preferably, one or more elements are contained.

Further, when the noble metal catalyst contains one or more elements selected from the group consisting of platinum group elements (hereinafter, also referred to as “catalyst first component”), as a catalyst component, tin, bismuth, It is preferable to contain one or more elements selected from the group consisting of selenium, zinc, lead, tellurium and antimony (hereinafter also referred to as “catalyst second component”).
Further, when the noble metal catalyst contains a first catalyst component and a second catalyst component, the catalyst component is further selected from one or more elements selected from rare earth elements (hereinafter also referred to as “catalyst third component”). ) Can be contained.
The ratio of the first catalyst component to the second catalyst component is preferably 0.001 or more, more preferably 0.005 or more in terms of the [catalyst second component / catalyst first component] atomic ratio, from the viewpoint of catalyst activity. 0.01 or more is more preferable, 10 or less is preferable, 7 or less is more preferable, and 6 or less is more preferable. In addition, the ratio of the first catalyst component to the third catalyst component is preferably 0.01 or more, and more preferably 5 or less in terms of the [catalyst third component / catalyst first component] atomic ratio.

The noble metal catalyst used in the oxidation method 2 is preferably used as a supported catalyst supported on a carrier. The carrier is preferably an inorganic carrier such as activated carbon, alumina, silica gel, activated clay, diatomaceous earth, clay, zeolite, silica, silica-alumina, silica-magnesia, silica-titania, titania, tin-titania, niobium, zirconia, and ceria. 1 type (s) or 2 or more types chosen from the group which consists of are mentioned. Of these, one or more selected from the group consisting of alumina, silica, titania, ceria, and activated carbon are more preferable.
The total supported amount of the first catalyst component is preferably 0.1% by mass or more, more preferably 1% by mass or more, further preferably 2.0% by mass or more, preferably 20% by mass or less, based on the total amount of the supported catalyst. More preferably, it is 15 mass% or less, More preferably, it is 13 mass% or less.
The total supported amount of the second catalyst component is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, still more preferably 0.05% by mass or more, preferably 20% by mass, based on the total amount of the supported catalyst. % Or less, more preferably 15% by mass or less, and still more preferably 10% by mass or less.
The total supported amount of the third catalyst component is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, still more preferably 0.1% by mass or more, preferably 20% by mass, based on the total amount of the supported catalyst. % Or less, more preferably 15% by mass or less, and still more preferably 5% by mass or less.

The noble metal catalyst used in the oxidation method 2 can be produced by a known method such as JP-A-62-269746. For example, an aqueous solution of a compound containing an element of the first catalyst component (palladium chloride, chloroplatinic acid, etc.), an aqueous solution of a compound containing the element of the second catalyst component (bismuth chloride, antimony pentachloride, etc.), It can be produced by a method in which an aqueous solution of a compound containing three elements (cerium chloride, lanthanum chloride, etc.) is adsorbed on a carrier such as activated carbon in water in a lump or divided and then the catalyst component is reduced.
The amount of the noble metal catalyst used is preferably 0.0001% by mass or more, more preferably 0.001% by mass or more, and still more preferably the total amount of the first catalyst component in the noble metal catalyst with respect to HMF from the viewpoint of catalyst activity. Is 0.01% by mass or more, preferably 2.0% by mass or less, more preferably 1.5% by mass or less, and still more preferably 1.0% by mass or less.
When the noble metal catalyst includes the first catalyst component and the second catalyst component, the total amount of the first catalyst component and the second catalyst component is preferably 0.0001% by mass or more with respect to HMF, and more preferably. Is 0.001% by mass or more, preferably 4.0% by mass or less, more preferably 3.0% by mass or less.
When the noble metal catalyst includes the first catalyst component, the second catalyst component, and the third catalyst component, the total amount of the first catalyst component, the second catalyst component, and the third catalyst component is preferably 0 with respect to the HMF. It is 0.001 mass% or more, More preferably, it is 0.01 mass% or more, Preferably it is 6.0 mass% or less, More preferably, it is 4.0 mass% or less.

(solvent)
In the oxidation method 2, it is preferable to use a solvent. As the solvent, water is preferable from the viewpoints of availability, economy and safety. Moreover, an organic solvent can also be used as needed. From the viewpoint of improving the productivity of the HMF oxide, the concentration of water in the liquid phase at the time of preparation is usually 0% by mass or more, preferably 5% by mass or more, and usually 99% by mass or less, and 95% by mass or less. Is preferable, and 80 mass% or less is more preferable.

(Oxidizing gas)
The oxidizing gas used in the oxidation method 2 is the same as the oxidizing gas used in the oxidation method 1 described above.
In the oxidation reaction of oxidation method 2, the amount of dissolved oxygen in the liquid phase is preferably 1 ppm or less, more preferably 0 to 0.8 ppm, and still more preferably 0 to 0.5 ppm, and then an oxidizing gas such as oxygen is supplied. It is preferable to start. In this way, the reaction proceeds promptly even in the initial reaction.
Before starting the supply of oxidizing gas, the amount of dissolved oxygen in the liquid phase is 1 ppm or less. (1) In the liquid phase, helium, argon, nitrogen, carbon dioxide, methane, ethane, propane, etc. (2) Add methanol, ethanol, propanol, formaldehyde, acetaldehyde, propionaldehyde, hydrogen, etc. that react with oxidizing gas to the reaction solution. Methods and the like. Among these, the method (1) is preferable from the viewpoints of operability and safety.
In the case of using an oxygen-containing mixed gas, the oxygen concentration in the gas to be blown is preferably 10% by volume or more, more preferably 20% by volume or more, but particularly preferably oxygen alone is blown.

(Reaction temperature)
The reaction temperature in the oxidation reaction by the oxidation method 2 is preferably 30 ° C. or higher, more preferably 35 ° C. or higher, still more preferably 40 ° C. or higher, preferably 200 ° C. or lower, from the viewpoints of oxygen solubility and low energy. Preferably it is 180 degrees C or less, More preferably, it is 150 degrees C or less.

(Reaction pressure)
Although the reaction pressure may be normal pressure, it is usually 0.01 MPa or more, usually 3.0 MPa or less, preferably 2.0 MPa or less, more preferably 1.5 MPa or less.

(Alkaline substance)
The oxidation of HMF by the oxidation method 2 is preferably performed in a liquid phase containing an alkaline substance. Examples of alkaline substances include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, alkaline earth metal hydroxides such as magnesium hydroxide and calcium hydroxide, alkali metal carbonates, and alkaline earth metal carbonates. 1 type (s) or 2 or more types selected from the group which consists of. Of these, alkali metal hydroxides are preferred from the viewpoints of reactivity and economy.
From the viewpoint of reaction rate and suppression of side reaction of HMF, it is preferable to use an alkaline substance in such an amount that the pH of the liquid phase is preferably 7.5 or more, more preferably pH 8 or more, more preferably pH 13 or less.

When the oxidation of HMF by oxidation method 2 is carried out in a liquid phase containing an alkaline substance, HMF, FDCA, and carboxylic acids are included in the liquid phase after completion of the reaction and after removal of the catalyst by a method such as filtration or centrifugation. Is dissolved in the form of a salt with an alkaline substance. If necessary, it can be acidified with a mineral acid such as hydrochloric acid to obtain an oxide of HMF.
From the viewpoint of simplifying the acidification step and improving productivity, it is preferable to oxidize HMF in water or an organic solvent without using an alkaline substance.

(5-hydroxymethylfurfural oxide)
Examples of the 5-hydroxymethylfurfural oxide of the present invention include 2,5-furandicarboxylic acid (FDCA), diformylfuran (DFF), 2-carboxy-5-formylfuran (CFF), 5-hydroxymethyl-2- One or more selected from the group consisting of furan carboxylic acid (HMFA) and 5-acetoxymethyl-2-furan carboxylic acid (AcMFA) can be mentioned, and the reaction conditions in step d can be appropriately selected for oxidation. By performing the reaction, a desired product can be produced. Among these, 2,5-furandicarboxylic acid (FDCA) is preferable from the viewpoint of usefulness as a chemical raw material.

The present invention discloses the following 5-hydroxymethylfurfural and its oxide with respect to the above-described embodiment.
<1> A method for producing 5-hydroxymethylfurfural, comprising the following steps a to c.
Step a: A step of dehydrating a sugar raw material in the presence of a reaction solvent to produce 5-hydroxymethylfurfural in the reaction solvent to obtain a reaction solvent containing 5-hydroxymethylfurfural Step b: obtained in Step a Extracting 5-hydroxymethylfurfural into a hydrophobic solvent from the obtained reaction solvent containing 5-hydroxymethylfurfural to obtain a hydrophobic solvent containing 5-hydroxymethylfurfural Step c: obtained in Step b Extracting 5-hydroxymethylfurfural into water from a hydrophobic solvent containing 5-hydroxymethylfurfural to obtain an aqueous solution containing 5-hydroxymethylfurfural

<2> The sugar raw material used in step a is preferably a sugar raw material containing fructose, more preferably fructose, a mixture of fructose and any monosaccharide, a disaccharide combining fructose and any monosaccharide, fructose Oligosaccharides combining sucrose and any monosaccharide, and polysaccharides combining fructose and any saccharose; high fructose corn syrup, its purified intermediates and by-products; derived from soy sugar liquor, sugarcane and sugar beet Sugar solution, and purified sugar, crude sugar, molasses, and invert sugar obtained from the sugar solution; and one or more selected from the group consisting of inulin, more preferably a mixture of glucose and fructose, fructose, sucrose, Purified sugar, crude sugar and waste from inulin and sugar solution derived from sugarcane and sugar beet It is one or more selected from the group consisting of honey, production method of 5-hydroxymethyl furfural according to <1>.
<3> Monosaccharide is preferably one or more selected from the group consisting of glucose, galactose, mannose and sorbose, more preferably one or more selected from the group consisting of glucose, mannose and galactose More preferably, the method for producing 5-hydroxymethylfurfural according to the above <2>, which is glucose.
<4> The concentration of the sugar raw material in the reaction solvent in step a is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, still more preferably 1% by mass or more, and further preferably 3% by mass or more. Preferably 80% by mass or less, more preferably 70% by mass or less, further preferably 60% by mass or less, and further preferably 50% by mass or less, according to any one of <1> to <3>. A process for producing 5-hydroxymethylfurfural.
<5> The reaction solvent used in step a is preferably a polar solvent, more preferably one or more selected from the group consisting of water, a highly polar aprotic organic solvent, and an ionic liquid, and more preferably Is one or two selected from the group consisting of water, dimethyl sulfoxide, dimethylacetamide, N, N-dimethylformamide, N-methyl-2-pyrrolidinone, acetone, methyl ethyl ketone, sulfolane, imidazolium salts, pyridinium salts, and tetrahydrofuran More preferably, one or more selected from the group consisting of water, dimethyl sulfoxide, N-methyl-2-pyrrolidinone, dimethylacetamide, acetone, imidazolium salts, and tetrahydrofuran, more preferably water, dimethyl sulfoxide, Acetone, imidazo Um salts, and is one or more selected from the group consisting of tetrahydrofuran, the <1> to <4> method for producing 5-hydroxymethyl furfural as claimed in any one of.

<6> The water-octanol partition coefficient of the hydrophobic solvent used in step b is preferably 0.3 or more, more preferably 0.4 or more, still more preferably 0.5 or more, and even more preferably 10 or less. The method for producing 5-hydroxymethylfurfural according to any one of <1> to <5>.
<7> The hydrophobic solvent used in step b is preferably an aliphatic ketone, an aliphatic ether, an aliphatic alcohol, an aliphatic ester, a lactone, an aromatic hydrocarbon, an aliphatic hydrocarbon, a halogen One or more selected from the group consisting of hydrofluoric hydrocarbons and hydrophobic ionic liquids, more preferably aliphatic ketones, aliphatic ethers, aliphatic alcohols, aliphatic esters, fatty acid amides , Aromatic hydrocarbons, aliphatic hydrocarbons, and halogenated hydrocarbons, one or more selected from the group consisting of halogenated hydrocarbons, more preferably 3-methyl-2-butanone, methyl isobutyl ketone, diisobutyl ketone 5-methyl-3-heptanone, cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, isophorone, tetrahydrofuran, Furfural, furfuryl alcohol, n-butanol, 2-butanol, n-amyl alcohol, isopentyl alcohol, hexyl alcohol, chloromethane, dichloromethane, trichloromethane, trichloroethane, diethyl ether, methyl-tert-butyl ether, diisopropyl ether, toluene, One or more selected from the group consisting of xylene, benzene, cumene, dichloroethane, decane, decene, dodecane, dodecene, hexane, pentane, petroleum ether, ethyl acetate, propyl acetate, and butyl acetate, more preferably methyl Isobutyl ketone, cyclohexanone, n-butanol, 2-butanol, n-amyl alcohol, dichloromethane, trichloromethane, diethyl ether, methyl-tert-butyl ether, di One or more selected from the group consisting of isopropyl ether, toluene, dichloroethane, hexane, ethyl acetate, propyl acetate, and butyl acetate, more preferably methyl isobutyl ketone, cyclohexanone, 2-butanol, dichloromethane, trichloromethane, diethyl 5-hydroxymethyl according to any one of the above <1> to <6>, which is one or more selected from the group consisting of ether, diisopropyl ether, ethyl acetate, butyl acetate, toluene, dichloroethane, and hexane Production method of furfural.

<8> The reaction solvent used in step a is water. In step a, a sugar raw material is subjected to a dehydration reaction in the presence of water and a hydrophobic solvent, and water containing 5-hydroxymethylfurfural and 5-hydroxymethylfurfural The method for producing 5-hydroxymethylfurfural according to any one of <1> to <7>, wherein the step a and the step b are simultaneously performed by obtaining a hydrophobic solvent containing:
<9> The water-octanol partition coefficient of the hydrophobic solvent is preferably 0.4 or more, more preferably 0.5 or more, preferably 10 or less, more preferably 7 or less, and even more preferably 5 or less. The method for producing 5-hydroxymethylfurfural as described in <8> above.
<10> The hydrophobic solvent is preferably one selected from the group consisting of aliphatic ketones, aliphatic alcohols, aliphatic esters, aliphatic ethers, aromatic hydrocarbons and halogenated hydrocarbons 2 or more, more preferably methyl isobutyl ketone, cyclohexanone, n-butanol, 2-butanol, n-amyl alcohol, cyclohexanol, dichloromethane, trichloromethane, toluene, xylene, benzene, cumene, benzonitrile, chlorobenzene, dichloroethane , Isophorone, ethyl acetate, propyl acetate and butyl acetate, or more preferably selected from the group consisting of methyl isobutyl ketone, cyclohexanone, n-butanol, 2-butanol, toluene and isophorone. Select from group 5-hydroxy as described in <8> or <9> above, which is one or more selected from the group consisting of methyl isobutyl ketone, isophorone, and toluene. A method for producing methylfurfural.
<11> The amount of the hydrophobic solvent used is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, still more preferably 0.2% by mass or more, and further preferably 1% by mass with respect to water. Or more, more preferably 2% by mass or more, further preferably 5% by mass or more, further preferably 10% by mass or more, preferably 100000% by mass or less, more preferably 50000% by mass or less, and further preferably 25000% by mass or less. More preferably, it is 10,000% by mass or less, more preferably 7500% by mass or less, further preferably 5000% by mass or less, and still more preferably 2500% by mass or less, according to any one of <8> to <10> above. -A process for producing hydroxymethylfurfural.
<12> After the completion of step b, before step c, the hydrophobic solvent used in the extraction in step b is distilled off, HMF is concentrated, and the resulting HMF concentrate is mixed with hydrophobic solvent and water. The method for producing 5-hydroxymethylfurfural according to any one of <1> to <11>, wherein the extraction is performed in the step c.
<13> The process for producing 5-hydroxymethylfurfural according to any one of <1> to <12>, which comprises the following step c-2.
Step c-2: One or more selected from the group consisting of the aqueous solution containing HMF obtained in Step c, preferably from dehydration, crystallization and recrystallization, solvent extraction, adsorption treatment, column chromatography and distillation. More preferably, one or more selected from the group consisting of dehydration, recrystallization, solvent extraction, and adsorption treatment, more preferably one or two selected from the group consisting of dehydration, recrystallization, and solvent extraction More preferably, the step of purifying HMF by recrystallization

<14> A method for producing 5-hydroxymethylfurfural oxide, comprising the step d of oxidizing 5-hydroxymethylfurfural obtained by the production method according to any one of <1> to <13>.
<15> The oxidation of 5-hydroxymethylfurfural in step d is performed by contacting with an oxidizing gas in the presence of a metal catalyst and a halogen compound in an organic acid solvent in the presence of a metal catalyst and a halogen compound. Production method of furfural oxide.
<16> The organic acid solvent is preferably one or more selected from the group consisting of acetic acid, propionic acid, and a mixed solvent of acetic acid / acetic anhydride, more preferably acetic acid, more preferably acetic acid. A process for producing 5-hydroxymethylfurfural oxide.
<17> The method for producing 5-hydroxymethylfurfural oxide according to <15> or <16>, wherein the metal catalyst is one or more selected from a cobalt catalyst and a manganese catalyst.
<18> The cobalt-based catalyst is preferably one or more selected from the group consisting of cobalt acetate, cobalt bromide, cobalt sulfate, cobalt nitrate, cobalt carbonate, cobalt chloride, and cobalt, more preferably cobalt acetate and The method for producing 5-hydroxymethylfurfural oxide according to <17>, wherein one or more selected from the group consisting of cobalt bromide, more preferably cobalt acetate.
<19> The manganese-based catalyst is preferably one or more selected from the group consisting of manganese acetate, manganese bromide, manganese sulfate, manganese nitrate, manganese carbonate, manganese chloride, and manganese, and more preferably acetic acid. The method for producing 5-hydroxymethylfurfural oxide according to the above <17>, which is one or more selected from the group consisting of manganese and manganese bromide, and more preferably manganese acetate.
<20> The halogen compound is preferably one selected from the group consisting of bromine, chlorine, fluorine, and iodine, and hydrides, alkali metal salts, cobalt salts, manganese salts, ammonium salts, and organic halides of these halogens. Or more, more preferably one or more selected from the group consisting of bromine, sodium bromide, potassium bromide, cobalt bromide, and manganese bromide, <15> to <19> The method for producing 5-hydroxymethylfurfural oxide according to any one of the above.
<21> The amount of the metal catalyst used is preferably 0.1 mol% or more, more preferably 0.5 mol% or more, still more preferably 1. mol% or more based on the raw material HMF obtained by the method including steps a to c. Any one of the above <15> to <20>, which is 0 mol% or more, preferably 60.0 mol% or less, more preferably 40.0 mol% or less, and still more preferably 15.0 mol% or less. A process for producing the 5-hydroxymethylfurfural oxide as described.
The amount of <22> halogen compound used is preferably 0.01 mol% or more, more preferably 0.1 mol% or more, preferably 20 mol% or more with respect to the raw material HMF obtained by the method including steps a to c. The production of 5-hydroxymethylfurfural oxide according to any one of <15> to <21>, which is 0.0 mol% or less, more preferably 15.0 mol% or less, and still more preferably 10.0 mol% or less. Method.

<23> The oxidation of 5-hydroxymethylfurfural in step d is performed by contacting with an oxidizing gas, preferably in the presence of a catalyst containing at least one metal element selected from Groups 8 to 11 of the periodic table. The method for producing 5-hydroxymethylfurfural oxide according to any one of <14> to <22>.
<24> The catalyst containing at least one metal element selected from the group consisting of Groups 8 to 11 of the periodic table is preferably from the group consisting of ruthenium, rhodium, palladium, osmium, iridium, platinum, gold, and cobalt. One or more elements selected, more preferably one or more elements selected from the group consisting of palladium, gold, ruthenium and platinum, more preferably selected from the group consisting of palladium and platinum The method for producing 5-hydroxymethylfurfural oxide according to the above <23>, which contains one or more elements.
<25> The catalyst preferably contains at least one metal element selected from the group consisting of ruthenium, rhodium, palladium, osmium, iridium, platinum, gold, and cobalt as the first catalyst component, and the second catalyst component The method for producing an oxide of 5-hydroxymethylfurfural according to the above <23> or <24>, which contains at least one element selected from the group consisting of tin, bismuth, selenium, tellurium and antimony.
<26> The 5-hydroxymethylfurfural oxide according to <25>, wherein the catalyst preferably further contains one or more elements selected from the group consisting of rare earth elements as the third component of the catalyst. Production method.
<27> The ratio of the catalyst first component to the catalyst second component is preferably 0.001 or more, more preferably 0.005 or more, and still more preferably 0, in terms of the atomic ratio of [catalyst second component / catalyst first component]. The method for producing an oxide of 5-hydroxymethylfurfural according to the above <25> or <26>, which is 0.01 or more, preferably 10 or less, more preferably 7 or less, and even more preferably 6 or less.
<28> The catalyst is preferably a supported catalyst supported on a carrier, and the carrier is preferably an inorganic carrier, more preferably activated carbon, alumina, silica gel, activated clay, diatomaceous earth, clay, zeolite, silica, silica-alumina. One or more selected from the group consisting of silica, magnesia, silica-titania, titania, tin-titania, niobium, zirconia, and ceria, more preferably the group consisting of alumina, silica, titania, ceria, and activated carbon The method for producing an oxide of 5-hydroxymethylfurfural according to any one of <23> to <27>, which is one or more selected from the group consisting of:
<29> The total amount of the first catalyst component in the catalyst containing one or more metal elements selected from the group consisting of Groups 8 to 11 of the periodic table is preferably 0.0001 mass relative to HMF. % Or more, more preferably 0.001% by mass or more, further preferably 0.01% by mass or more, preferably 2.0% by mass or less, more preferably 1.5% by mass or less, and still more preferably 1.0% by mass. The method for producing an oxide of 5-hydroxymethylfurfural according to any one of <23> to <28>, wherein the oxide is 5% by mass or less.
<30> The total amount of the catalyst first component and the catalyst second component is preferably 0.0001% by mass or more, more preferably 0.001% by mass or more, preferably 4.0% by mass with respect to HMF. % Or less, more preferably 3.0% by mass or less, The method for producing an oxide of 5-hydroxymethylfurfural according to any one of <25> to <29> above.
<31> The total use amount of the first catalyst component, the second catalyst component, and the third catalyst component is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, preferably with respect to HMF. The method for producing an oxide of 5-hydroxymethylfurfural according to any one of <26> to <30>, wherein is 6.0% by mass or less, more preferably 4.0% by mass or less.
<32> 5-hydroxymethylfurfural oxide is preferably 2,5-furandicarboxylic acid, diformylfuran, 2-carboxy-5-formylfuran, 5-hydroxymethyl-2-furancarboxylic acid, and 5-acetoxy The 5-hydroxy according to any one of <14> to <31>, which is one or more selected from the group consisting of methyl-2-furancarboxylic acid, more preferably 2,5-furandicarboxylic acid A method for producing methylfurfural oxide.

Hereinafter, examples and the like specifically showing the present invention will be described. In the following examples and comparative examples, “%” means “mass%” unless otherwise specified.

<Sugar conversion and hexose content>
Measurement was performed by high performance liquid chromatography. The sugar content in the biomass raw material was also calculated by the following method. Moreover, it measured by the following measuring method 1 or measuring method 2 according to the kind of sugar raw material.
(Measurement method 1)
・ Detector: CAD
Column: Shodex Asahipak NH2P-50 4E
・ Temperature: 25 ℃
・ Eluent: a) Acetonitrile b) Water containing 30% methanol ・ Flow rate: 1.0 mL / min ・ Measurement sample dilution solvent: Pure water (Measurement method 2)
・ Detector: RI
Column: ICSep COREGEL-87H
・ Temperature: 80 ℃
-Eluent: water containing 0.1% trifluoroacetic acid-Flow rate: 0.6 mL / min
・ Measurement sample dilution solvent: pure water

<HMF yield, HMF extraction rate, organic acid content>
Measurement was performed by high performance liquid chromatography.
・ Detector: RI
Column: ICSep COREGEL-87H
・ Temperature: 80 ℃
・ Eluent: Water containing 0.1% trifluoroacetic acid ・ Flow rate: 0.6 mL / min
・ Measurement sample dilution solvent: pure water

<HMF purity>
Measurement was performed by gas chromatography.
-GC equipment: 6850, manufactured by Agilent Technologies
・ Column: DB-WAX (30 m × 0.25 mm × 0.25 μm) manufactured by Agilent Technologies
・ Detector: FID
Carrier: Helium gas, 24.5 mL / min Temperature rising conditions: 40 ° C. held for 10 minutes, heated from 40 ° C. to 230 ° C. at 10 ° C./min. Thereafter, maintained at 230 ° C for 8 minutes.
Carrier gas: Helium, 24.5 mL / min Internal standard: Tetradecane Measurement sample diluent solvent: Acetone

<Water content in HMF composition>
Measurement was performed by volumetric titration using a Karl Fischer moisture meter.

<HMF oxidation composition>
Measurement was performed by high performance liquid chromatography.
・ Detector: UV
・ Column: L-column2 ODS
・ Temperature: 40 ℃
-Eluent: water containing 0.1% trifluoroacetic acid, methanol containing 0.1% trifluoroacetic acid-Flow rate: 1.0 mL / min

<Water-octanol partition coefficient of solvent (Log P value)>
The water-octanol partition coefficient of the hydrophobic solvent used in the examples is as shown in Table 1.
The “Log P value” in this specification means the logarithmic value of the 1-octanol / water partition coefficient of the solvent, and is calculated using the fragment approach by SRC's LOGKOW / KOWWIN Program of KowWin (Syracuse Research Corporation, USA). The KowWin Program methodology is described in the following journal article: Meylan, WM and PH Howard. 1995. Atom / fragment contribution method for using octanol-water partition coefficients. J. Pharm. Sci. 84: 83- 92.).
The fragment approach is based on the chemical structure of the compound and takes into account the number of atoms and the type of chemical bond. The LogP value is a numerical value generally used for relative evaluation of the hydrophilicity / hydrophobicity of an organic compound.

Example 1 (Production of HMF from fructose)
(Process a and Process b)
1L glass solenoid valve autoclave (made by pressure-resistant glass industry), 40g of D-fructose (made by Wako Pure Chemical Industries) as sugar raw material, 80g of ion-exchanged water as reaction solvent, MIBK (Wako Pure Chemical Industries, Ltd.) as hydrophobic solvent 320 g manufactured by Kogyo Co., Ltd., LogP value: 1.31) and 4.0 g phosphoric acid (purity 85%, manufactured by Sigma-Aldrich Japan Co., Ltd.) were charged as a catalyst. After sealing the container, the internal space was sufficiently replaced with nitrogen. Thereafter, the contents were heated to 140 ° C. with sufficient stirring, and then reacted for 3 hours while keeping the temperature and stirring. The gauge pressure during the reaction was 0.4 MPa.
After the reaction was completed, the contents were cooled while maintaining stirring until the temperature of the contents became 30 ° C or lower. After cooling, the content was filtered, and the filtrate was agitated and neutralized by adding 50% aqueous sodium hydroxide dropwise to adjust the pH of the content to 7. After neutralization, the contents were filtered to remove insoluble matters.
After removing insoluble matter, samples were taken from each of the aqueous solution layer and MIBK solution layer, diluted with pure water, and the peak areas of D-fructose and HMF were measured by high performance liquid chromatography. From the peak areas of D-fructose and 5-hydroxymethylfurfural in the obtained chromatogram, the D-fructose and 5-hydroxymethylfurfural concentration-area relations prepared in advance were used to determine the D- When the fructose and HMF concentrations were calculated, the conversion of D-fructose was 93%, and it was confirmed that 73% (20.4 g) of HMF was formed based on the molar amount of D-fructose charged.

(Process b)
Each of the aqueous solution layer and the MIBK solution layer of the filtrate obtained after the completion of the reaction in (Step a and Step b) and after neutralization was separated. The obtained aqueous solution phase was transferred to a separatory funnel, and 0.5 times mass of MIBK was added to the aqueous solution phase to separate and extract HMF in the aqueous solution layer. This extraction operation was performed three times, and the MIBK solution layer obtained by the extraction operation was mixed with the MIBK solution layer after completion of the reaction separated and neutralized, and the MIBK solution layer was mixed with a rotary evaporator (50 ° C. warm bath). Was distilled off and HMF was concentrated. When measured by high performance liquid chromatography in the same manner as in step a, the mass of HMF in the concentrate was 20.1 g, and the HMF extraction recovery rate was 98.6%. Further, the concentrated solution and tetradecane (internal standard substance) were mixed and diluted with acetone (manufactured by Wako Pure Chemical Industries, Ltd.), and the peak areas of HMF and tetradecane were measured by gas chromatography. From the peak area ratio of 5-hydroxymethylfurfural and tetradecane and the sample preparation mass ratio in the obtained chromatogram, the relational expression of the area ratio-mass ratio of 5-hydroxymethylfurfural and tetradecane prepared in advance was used. The HMF purity in the sample was calculated, and the HMF purity was 82.2% by mass. The water content in the HMF concentrate was 2.6% by mass.
The same operation was performed to obtain 11.0 g of HMF concentrate (HMF purity: 79.7%).
Further, the same operation was performed to obtain 4.1 g of HMF concentrate (HMF purity 80.3%).

(Process c)
After weighing 1.0 g (HMF purity 82.2%) of the HMF concentrate obtained in the above (step b), this was transferred to a separatory funnel, and 5.0 g of MIBK was added to dilute the HMF concentrate. 7.5 g of ion-exchanged water was added, and a liquid separation extraction operation of HMF in the organic solvent layer was performed. This extraction operation was performed three times, and the aqueous solution obtained by the extraction operation was concentrated with a rotary evaporator (50 ° C. warm bath) to obtain an HMF concentrate. The extraction recovery rate of HMF and the HMF purity in the HMF concentrate were measured in the same manner as in step b of Example 1. The HMF extraction rate into the aqueous layer was 88.5%, and the HMF purity in the HMF concentrate was 83. The content of water in the 0% by mass HMF concentrate was 13.3% by mass. The residual amount of MIBK in the concentrate was below the detection limit as measured by gas chromatography.

Examples 2-4
Example 1 except that in Step c, 5.0 g of cyclohexanone (Example 2), dichloromethane (Example 3), and ethyl acetate (Example 4) were used in place of the methyl isobutyl ketone used in Example 1. HMF concentrate was obtained in the same manner as above. Table 2 shows the HMF extraction rate into the aqueous layer in step c, the HMF purity in the HMF concentrate, and the moisture content.

Examples 5 to 10
In Step c, instead of methyl isobutyl ketone used in Example 1, butyl acetate (Example 5), diethyl ether (Example 6), diisopropyl ether (Example 7), methyl isobutyl ketone / n-hexane = 1 / 1 (mass ratio) (Example 8), methyl isobutyl ketone / toluene = 1/1 (mass ratio) (Example 9), 2-butanol / n-hexane = 1/1 (mass ratio) (Example 10) ) Was used in the same manner as in Example 1 except that 10.0 g was used and the amount of ion-exchanged water used was changed to 15.0 g. Table 2 shows the HMF extraction rate into the aqueous layer in step c, the HMF purity in the HMF concentrate, and the moisture content.

Example 11 (Production of HMF from molasses 1)
(Process a and Process b)
As a raw material for sugar, 40 g of molasses containing 24.4% by mass of sucrose, 7.0% by mass of glucose, 9.9% by mass of fructose and 25.4% by mass of water, reaction temperature of 150 ° C., reaction time The reaction and cooling were carried out in the same manner as in Example 1 except that was changed to 1 hour. The gauge pressure during the reaction was 0.5 MPa. After cooling, the contents were filtered to remove solids, and then analyzed in the same manner as in Example 1. As a result, the conversion rate of sucrose was 99%, the conversion rate of fructose was 92%, the conversion rate of glucose was 42%, and production of 12.4% (4.97 g) of HMF based on the mass of the charged molasses. It was confirmed.

(Process b)
The filtrate obtained after the completion of the reaction (step a and step b) and after cooling was separated into an aqueous solution layer and a methyl isobutyl ketone solution layer. The separated aqueous solution layer (22.5 g) and methyl isobutyl ketone solution layer (100.2 g) were mixed and neutralized by adding an 8N aqueous sodium hydroxide solution dropwise with stirring to adjust the pH of the filtrate to 7.
Then, the liquid separation extraction operation of HMF in an aqueous solution layer was performed by the method similar to the process b of Example 1. The HMF content in the aqueous solution layer after the extraction operation was 0.045 g, the HMF content in the methyl isobutyl ketone solution layer was 1.350 g, and the HMF extraction recovery was 96.8%.
Thereafter, the obtained methyl isobutyl ketone solution layer was concentrated in the same manner as in Example 1 to obtain an HMF concentrate. The HMF purity in the concentrate was 73.3% by mass. The water content in the HMF concentrate was 2.7% by mass.

(Process c)
4.7 g of the HMF concentrate obtained in the above (step b) was prepared. The extraction operation was performed in the same manner as in Example 1 except that 4.7 g of the HMF concentrate prepared above, 50 g of dichloromethane as a hydrophobic solvent, and 30 g of ion-exchanged water were used, and the extraction operation was performed four times. A concentrate was obtained. The HMF extraction rate into the aqueous layer was 96.7%, and the HMF purity in the HMF concentrate was 96.0%. The residual amount of dichloromethane in the concentrate was 0.05% by mass or less as measured by gas chromatography. The water content in the HMF concentrate was 3.2% by mass. The results are shown in Table 3.

Example 12 (Production of HMF from molasses 2)
Step a and step b were performed in the same manner as in Example 11 to prepare 6.5 g of HMF concentrate (HMF purity: 73.6%).
Next, as step c, Example 5 was carried out except that 6.5 g of the HMF concentrate prepared above, 19.6 g of methyl isobutyl ketone and 19.6 g of ion-exchanged water were used as the hydrophobic solvent, and the extraction operation was performed 5 times. In the same manner as in No. 11, an HMF concentrate was obtained. The HMF extraction rate into the aqueous layer was 87.9%, and the HMF purity in the HMF concentrate was 92.1%. The residual amount of methyl isobutyl ketone in the concentrate was 0.05% by mass or less as measured by gas chromatography. The water content in the HMF concentrate was 3.9% by mass. The results are shown in Table 3.

Example 13
(Step c-2: Solvent extraction)
1.49 g of the HMF concentrate prepared in the same manner as in Steps a to c of Example 1 was dissolved in 1.5 ml of ethyl acetate. The obtained ethyl acetate solution was slowly added dropwise to 50 ml of toluene in a glass beaker and stirred. After completion of dropping, the solution was allowed to stand and the organic solvent layer was separated. The residue obtained after separating the organic solvent layer was again dissolved in 1.5 ml of ethyl acetate and collected.
The recovered ethyl acetate solution was again subjected to the same steps as above to separate the organic solvent layer. The obtained organic solvent layers were mixed and concentrated with a rotary evaporator (50 ° C. warm bath) to obtain 1.20 g of an orange HMF concentrate. The HMF purity in the concentrate was 98.2%.

Example 14
(Step c-2: Recrystallization)
1.20 g of the HMF concentrate obtained in Example 13 was dissolved in 100 g of toluene and allowed to cool and stand in a freezer at −30 ° C. to precipitate light yellow needle crystals. The toluene solution was collected and concentrated with a rotary evaporator (50 ° C. warm bath), and the same operation was performed twice. The crystals were washed with sufficiently cooled toluene and dried under reduced pressure to obtain 0.86 g of pale yellow needle crystals. The HMF purity of the pale yellow needle crystal was 99% or more.

Example 15 (Production of HMF from molasses 3)
(Process a)
In an autoclave (manufactured by Nitto Koatsu Co., Ltd.) equipped with a 100 mL Teflon (registered trademark) container, 6.0 g of molasses used in Example 11 as a sugar raw material, 53.7 g of ion-exchanged water as a reaction solvent, and sulfuric acid ( 0.3 g of Wako Pure Chemical Industries, Ltd. was charged. After sealing the container, the internal space was sufficiently replaced with nitrogen. Thereafter, the contents were heated to 150 ° C. with sufficient stirring, and then the reaction was carried out for 2.5 hours while maintaining the temperature and stirring.
After the reaction was completed, the contents were cooled while maintaining stirring until the temperature of the contents became 30 ° C or lower. After cooling, the filtrate contents were neutralized by dropwise addition of 8N aqueous sodium hydroxide while stirring to adjust the pH of the filtrate contents to 7. After neutralization, the contents were filtered to remove insolubles, and an aqueous solution of HMF was obtained. The obtained aqueous solution phase was collected, diluted with pure water, and measured by liquid chromatography. As a result, production of 0.46 g of HMF was confirmed. This corresponds to 30% on a molar basis of sucrose, glucose and fructose in the charged molasses.

(Process b)
The aqueous solution of HMF obtained in the same method step a as above is mixed and transferred to a separatory funnel, 0.33 times the mass of methyl isobutyl ketone is added to the aqueous solution phase, and the separation extraction operation of HMF in the aqueous solution layer is performed. Went. This extraction operation was performed 4 times, the methyl isobutyl ketone solution layer obtained by the extraction operation was mixed, methyl isobutyl ketone was distilled off with a rotary evaporator (50 ° C. warm bath), and HMF was concentrated. When measured by high performance liquid chromatography, the mass of HMF in the concentrate was 0.7 g, the purity was 81 mass%, and the HMF extraction recovery was 76%.

(Process c)
Transfer the HMF concentrate obtained in step b to a separatory funnel, add 5.0 g of ethyl acetate as a hydrophobic solvent, dilute the HMF concentrate, add 5.0 g of ion-exchanged water, and in the organic solvent layer The liquid separation extraction operation of HMF was performed. This extraction operation was performed 5 times, and the aqueous solution obtained by the extraction operation was concentrated with a rotary evaporator (50 ° C. warm bath) to obtain an HMF concentrate. When the HMF extraction recovery rate and the HMF purity in the HMF concentrate were measured, the HMF extraction rate into the aqueous layer was 96.7%, and the HMF purity in the HMF concentrate was 88.7% by mass. The water content in the HMF concentrate was 3.1% by mass.

Example 16 (Production of HMF from molasses 4)
(Process a)
A 200 mL glass four-necked flask was charged with 16.2 g of molasses used in Example 11 as a sugar raw material, 64.8 g of dimethyl sulfoxide (manufactured by Sigma-Aldrich Japan) as a reaction solvent, and 1.6 g of phosphoric acid as a catalyst. It is. Nitrogen was passed through the inner space of the container at a rate of 50 ml / min, and the contents were heated to 140 ° C. while sufficiently stirring the contents, and then the reaction was carried out for 3 hours while keeping the temperature and stirring.
After the reaction was completed, the contents were cooled while maintaining stirring until the temperature of the contents became 30 ° C or lower. After cooling, analysis was performed in the same manner as in Example 1. As a result, the conversion rate of sucrose was 99% or more, the conversion rate of fructose was 99% or more, the conversion rate of glucose was 28%, and 14.8% (2.38 g) of HMF based on the mass of the charged molasses. Confirmed the generation of.

(Process b)
A dimethyl sulfoxide solution containing 7.7 g of HMF obtained by the same method as in the above step a was distilled under reduced pressure at 0.6 kPa to distill off the dimethyl sulfoxide to obtain 24.2 g of an HMF concentrate. To the obtained HMF concentrate, 105.0 g of ion-exchanged water was added to dilute the concentrate.
A double mass of dichloromethane was added to 25.0 g of the obtained aqueous solution, and a separation extraction operation of HMF in the aqueous solution layer was performed. This extraction operation was performed 3 times, the dichloromethane solution layer obtained by the extraction operation was mixed, dichloromethane was distilled off with a rotary evaporator (50 ° C. warm bath), and HMF was concentrated. When measured by high performance liquid chromatography, the mass of HMF in the concentrate was 0.34 g, the purity was 61.6 mass%, and the content of dimethyl sulfoxide was 19.4 mass%. The extraction recovery rate of HMF was 76.2%.

(Process c)
Transfer the HMF concentrate obtained in step b to a separatory funnel, add 10.0 g of dichloromethane as a hydrophobic solvent, dilute the HMF concentrate, and then add 7.0 g of ion-exchanged water and 0.1 g of isopropanol. Then, liquid separation extraction operation of HMF in the organic solvent layer was performed. This extraction operation was performed 4 times, and the aqueous solution obtained by the extraction operation was concentrated with a rotary evaporator (50 ° C. warm bath) to obtain an HMF concentrate. When the extraction recovery rate of HMF and the HMF purity in the HMF concentrate were measured, the HMF extraction rate into the aqueous layer was 94.5%, and the HMF purity in the HMF concentrate was 74.5% by mass. The water content in the HMF concentrate was 1.6% by mass, and the content of dimethyl sulfoxide was 19.6% by mass.

Example 17 (HMF production 5 from waste molasses)
Step a was performed in the same manner as in Example 16.
The same extraction operation as in Step b of Example 16 was performed except that methyl isobutyl ketone was used as the hydrophobic solvent in Step b of Example 16. The mass of HMF in the concentrate was 0.40 g, the purity was 61.1% by mass, and the content of dimethyl sulfoxide was 3.3% by mass. The extraction recovery rate of HMF was 91.8%.
The extraction operation was performed in the same manner as in Step c of Example 16, except that methyl isobutyl ketone was used as the hydrophobic solvent in Step c of Example 16. The HMF extraction rate into the aqueous layer was 83.5%, and the HMF purity in the HMF concentrate was 69.0% by mass. Further, the water content in the HMF concentrate was 2.9% by mass, and the content of dimethyl sulfoxide was 4.3% by mass.

Example 18 (Production of HMF from fructose)
(Process c: Water extraction purification)
5.5 g (HMF purity 82.2%) of the HMF concentrate obtained in step b of Example 1 was weighed, transferred to a separatory funnel, and dichloromethane (Wako Pure Chemical Industries, Log P value: 1. 25) After adding 40.0 g and diluting the HMF concentrate, 1.0 g of isopropyl alcohol (manufactured by Kanto Chemical Co., Inc.) and 20.0 g of ion-exchanged water are added, and the separation and extraction of HMF in the organic solvent layer is performed. It was. This extraction operation was performed 5 times, and the aqueous solution obtained by the extraction operation was concentrated with a rotary evaporator (50 ° C. warm bath) to obtain an HMF concentrate. The HMF extraction rate into the aqueous layer was 92%, and the HMF purity in the HMF concentrate was 97.0%.

Example 19 (Production of HMF from fructose)
(Process c: Water extraction purification)
5.0 g (purity 82.2%) of the HMF concentrate obtained by the same operation as in step b of Example 1 was weighed, transferred to a separatory funnel, and cyclohexanone (manufactured by Sigma-Aldrich Japan) 40.0 g. After diluting the HMF concentrate, 20.0 g of ion-exchanged water was added, and the separation and extraction of HMF in the organic solvent layer was performed. This extraction operation was performed 5 times, and the aqueous solution obtained by the extraction operation was concentrated with a rotary evaporator (50 ° C. warm bath) to obtain an HMF concentrate. The HMF extraction rate into the aqueous layer was 51.0%, and the HMF purity in the HMF concentrate was 95.9%.

Example 20 (Production of HMF from fructose)
(Step c-2: Solvent extraction purification)
1.5 g of the HMF concentrate obtained in step c of Example 1 was dissolved in 1.5 ml of ethyl acetate (Wako Pure Chemical Industries, Ltd., Log P value: 0.73). The obtained ethyl acetate solution was slowly added dropwise while stirring 50 ml of toluene (manufactured by Wako Pure Chemical Industries, Ltd.) in a glass beaker in advance. After completion of dropping, the solution was allowed to stand and the organic solvent layer was separated. The residue was again dissolved in 1.5 ml of ethyl acetate and collected. The collected ethyl acetate solution was again subjected to the above step, and the organic solvent layer was separated. The obtained organic solvent layers were mixed and concentrated with a rotary evaporator (50 ° C. warm bath) to obtain 1.2 g of orange HMF concentrate. The HMF purity in the concentrate was 98.2%.

Example 21 (Production of HMF from fructose)
(Step c-2: Recrystallization purification)
1.2 g of the HMF concentrate obtained in Example 20 was dissolved in 100 g of toluene and allowed to cool and stand at −30 ° C. to precipitate pale yellow needle crystals. The toluene solution was collected and concentrated with a rotary evaporator (50 ° C. warm bath), and the same operation was repeated twice. The obtained crystals were washed with sufficiently cooled toluene and dried under reduced pressure. 0.9 g of pale yellow needle crystals were obtained.
The same operation was repeated to obtain 4.5 g of pale yellow needle crystals. The HMF purity in the concentrate was 96.7%.

Example 22 (Production of 2,5-furandicarboxylic acid (FDCA) by oxidation method 1)
HMF (purity 97.0%) 3.97 g obtained in Example 18 in a 500 mL titanium solenoid valve autoclave (manufactured by Nitto High Pressure Co., Ltd.), 44.89 g of acetic acid (manufactured by Wako Pure Chemical Industries, Ltd.), 0.27 g Of cobalt acetate (manufactured by Wako Pure Chemical Industries, Ltd.), 0.47 g of manganese acetate (manufactured by Sigma Aldrich Japan), and 0.10 g of sodium bromide (manufactured by Wako Pure Chemical Industries, Ltd.) were charged. After sealing the container, the internal space was sufficiently replaced with oxygen. Thereafter, the contents were heated to 150 ° C. with sufficient stirring, and maintained at 0.3 MPa while supplying oxygen to the internal space. Thereafter, the reaction was carried out for 3 hours while maintaining the temperature and stirring. After the reaction was completed, the contents were cooled while maintaining stirring until the temperature of the contents became 30 ° C or lower. After cooling, the contents were filtered to separate the solid and the filtrate, and the solid and the filtrate were diluted with a mixed solution of pure water and methanol and measured by liquid chromatography.
HMF measured the peak area of HMF in the chromatogram obtained by the UV detection method (absorption wavelength: 254 nm), and calculated the concentration in the sample using the HMF concentration-area relational expression prepared in advance. . As a result, the conversion of HMF was 100% based on the amount of HMF charged, and the yield of HMF oxide was 80.9% (3.78 g). Among them, the yield of FDCA was 73.8% (3.52 g), and the yield of DFF was 7.1% (0.27 g).

Example 23 (Production of FDCA and formylfuran (DFF) by oxidation method 1)
4.53 g of HMF (purity 96.7%) obtained in Example 21, 41.93 g of acetic acid (manufactured by Wako Pure Chemical Industries, Ltd.), 0.26 g of cobalt acetate, 0.52 g of manganese acetate, 0.14 g The reaction was conducted under the same conditions as in Example 22 except that sodium bromide was charged, and measurement was performed by liquid chromatography.
As a result, the conversion of HMF was 99.9% based on the amount of HMF charged, and the yield of HMF oxide was 84.2% (4.42 g). Among them, the yield of FDCA was 71.0% (3.85 g), and the yield of DFF was 13.1% (0.57 g).

Comparative Example 1 (Production of HMF from fructose)
(Step c-2: Adsorption treatment purification)
Purified by column chromatogram using 6.37 g (HMF content: 3.96 g, HMF purity: 62.2%) of the HMF concentrate obtained in step b of Example 1 (step c was not carried out). . In a glass column container, 200 g of silica (Silica Gel 60N, 40-50 μm, manufactured by Kanto Chemical Co., Inc.) and a developing solvent were mixed and put. The developing solvent used was prepared by mixing acetone (made by Wako Pure Chemical Industries) and hexane (made by Wako Pure Chemical Industries) at 1: 1 (volume ratio). The HMF concentrate was fractionated into a test tube by a certain amount by a column, and the solvent was distilled off to obtain 4.1 g of HMF concentrate. The HMF recovery rate was 99.7%, and the HMF purity in the concentrate was 94.7%.

Comparative Example 2 (Production of FDCA by oxidation method 1)
10.0 g of HMF (purity 79.7%) obtained by step b of Example 1 (step c not carried out), 48.85 g of acetic acid, 0.31 g of cobalt acetate, 0.59 g of manganese acetate, The reaction was conducted under the same conditions as in Example 22 except that 0.14 g of sodium bromide was charged, and the measurement was performed by liquid chromatography.
As a result, the conversion of HMF was 99.9% based on the amount of HMF charged, and FDCA was confirmed as a HMF oxide in a yield of 1.3% (0.12 g).

Comparative Example 3 (Production of FDCA, DFF, and CFF by oxidation method 1)
Other than charging 3.92 g of HMF (purity 94.7%) obtained in Comparative Example 1, 46.05 g acetic acid, 0.07 g cobalt acetate, 0.15 g manganese acetate, 0.06 g sodium bromide. Were reacted under the same conditions as in Example 22 and measured by liquid chromatography.
As a result, the conversion of HMF was 94.1% based on the amount of HMF charged, and the yield of HMF oxide was 0.5% (0.018 g). Among them, the yield of FDCA was 0.3% (0.012 g), the yield of DFF was 0.1% (0.003 g), and the yield of CFF was 0.1% (0.003 g).

Example 24 (Production of 2,5-furandicarboxylic acid (FDCA) by oxidation method 2)
A catalyst (Evonik Deguss, Inc.) in which a 50 ml glass three-necked flask was loaded with 1.71 g of HMF (purity 95.9%) obtained in Example 19, 4% palladium, 1% platinum, 5% bismuth on activated carbon. Manufactured, water content 53.7%) 0.19 g and ion-exchanged water 12.92 g. Next, a stirring blade (crescent moon type), an oxygen gas introduction pipe, a discharge pipe and a thermometer were attached to the flask. The liquid phase was stirred at 400 rpm, and the temperature of the reaction liquid (liquid phase) was increased to 60 ° C. in 16 minutes while flowing nitrogen at 50 ml / min. Next, an oxidation reaction was carried out for 24 hours while 2.15 g of a 48% aqueous sodium hydroxide solution (25.80 mmol as sodium hydroxide) and oxygen were blown at a rate of 100 mol% / hour (to the HMF charge ratio).
After completion of the reaction, the catalyst was filtered off from the reaction solution to obtain an aqueous solution of HMF. The aqueous phase was collected, diluted with a mixture of pure water and methanol, and measured by liquid chromatography. As a result, the conversion of HMF was 99.6% based on the amount of HMF charged, and FDCA (sodium salt type) was confirmed as the HMF oxide in a yield of 37.3% (0.97 g).

Example 25 (Production of FDCA by oxidation method 2)
HMF obtained by Example 20 (purity 98.2%) 1.21 g, 4% palladium, 1% platinum, catalyst having 5% bismuth supported on activated carbon (manufactured by Evonik Degussa, water content 53.7%) 0.18 g and 9.07 g of ion-exchanged water were respectively added, and the temperature of the reaction solution (liquid phase) was increased to reach 60 ° C. in 23 minutes, and 1.79 g of 48% sodium hydroxide aqueous solution (sodium hydroxide The same operation as in Example 24 was performed except that the reaction was performed for 27 hours.
As a result, the conversion of HMF was 100% on the basis of the amount of HMF charged, and FDCA (sodium salt type) was confirmed as the HMF oxide in a yield of 56.0% (1.03 g).

Comparative Example 4 (Production of FDCA and CFF by oxidation method 2)
HMF (purity 80.3%) obtained by step b of Example 1 (purity 80.3%) 3.57 g, catalyst with 4% palladium, 1% platinum, 5% bismuth supported on activated carbon (Evonik Degussa Co., Ltd. (water content 53.7%) was charged with 0.38 g and ion-exchanged water 27.76 g. The temperature of the reaction solution (liquid phase) reached 60 ° C. in 15 minutes, and 48% The same operation as in Example 24 was performed except that 4.01 g of sodium hydroxide aqueous solution (48.12 mmol as sodium hydroxide) was added and the reaction was performed for 30 hours.
As a result, the conversion of HMF was 100% based on the amount of HMF charged, and the yield of HMF oxide was 26.9% (1.08 g). Among them, the yield of FDCA (sodium salt type) was 25.9% (1.04 g), and the yield of CFF was 1.0% (0.04 g).

According to the above Examples 1 to 21, it can be seen that high-purity 5-hydroxymethylfurfural can be efficiently and economically produced by a simple extraction operation using a hydrophobic solvent and a reaction solvent. Furthermore, according to the above Examples 22 to 25, high-purity 5-hydroxymethylfurfural oxide is efficiently and economically produced by simply oxidizing the 5-hydroxymethylfurfural obtained as described above. I can see that
On the other hand, in Comparative Examples 2 to 4 where the step c according to the method of the present invention is not performed, it can be seen that even if the step d is performed, the oxidation is inhibited and 5-hydroxymethylfurfural oxide cannot be obtained in good yield.

The HMF obtained by the production method of the present invention is expected to be used as an intermediate raw material for PET substitute resins, fuels, chemicals, surfactants, cosmetics and the like as a biorefinery base material, and to be used for pharmaceuticals and functional foods. Development is also expected. Further, the HMF oxide obtained by the production method of the present invention can be suitably used as an intermediate in the fields of resins, toner binder monomers, pharmaceuticals, agricultural chemicals, fragrances and the like.

Claims (12)

1. A process for producing 5-hydroxymethylfurfural, comprising the following steps a to c.
   Step a: A step of dehydrating a sugar raw material in the presence of a reaction solvent to produce 5-hydroxymethylfurfural in the reaction solvent to obtain a reaction solvent containing 5-hydroxymethylfurfural Step b: obtained in Step a Extracting 5-hydroxymethylfurfural into a hydrophobic solvent from the obtained reaction solvent containing 5-hydroxymethylfurfural to obtain a hydrophobic solvent containing 5-hydroxymethylfurfural Step c: obtained in Step b Extracting 5-hydroxymethylfurfural into water from a hydrophobic solvent containing 5-hydroxymethylfurfural to obtain an aqueous solution containing 5-hydroxymethylfurfural
2. The production of 5-hydroxymethylfurfural according to claim 1, wherein the reaction solvent used in step a is one or more selected from the group consisting of water, a highly polar aprotic organic solvent, and an ionic liquid. Method.
3. The method for producing 5-hydroxymethylfurfural according to claim 1 or 2, wherein the hydrophobic solvent used in step b has a water-octanol partition coefficient of 0.3 or more.
4. The hydrophobic solvent used in step b is one selected from the group consisting of methyl isobutyl ketone, cyclohexanone, 2-butanol, dichloromethane, trichloromethane, diethyl ether, diisopropyl ether, ethyl acetate, butyl acetate, toluene, dichloroethane, and hexane Alternatively, the method for producing 5-hydroxymethylfurfural according to any one of claims 1 to 3, wherein two or more are used.
5. The reaction solvent used in step a is water, and in step a, a sugar raw material is subjected to a dehydration reaction in the presence of water and a hydrophobic solvent, and water containing 5-hydroxymethylfurfural and hydrophobic containing 5-hydroxymethylfurfural. The method for producing 5-hydroxymethylfurfural according to any one of claims 1 to 4, wherein the step a and the step b are simultaneously performed by obtaining a neutral solvent.
6. The method for producing 5-hydroxymethylfurfural according to any one of claims 1 to 5, further comprising the following step c-2.
   Step c-2: From the aqueous solution containing 5-hydroxymethylfurfural obtained in Step c, 5-hydroxymethyl by one or more selected from the group consisting of dehydration, recrystallization, solvent extraction, and adsorption treatment Process for purifying furfural
7. A method for producing 5-hydroxymethylfurfural oxide, comprising a step d of oxidizing 5-hydroxymethylfurfural obtained by the production method according to any one of claims 1 to 6.
8. The oxidation of 5-hydroxymethylfurfural oxide in step d is performed by contacting with an oxidizing gas in an organic acid solvent in the presence of a metal catalyst and a halogen compound. Production method.
9. The method for producing 5-hydroxymethylfurfural oxide according to claim 8, wherein the metal catalyst is one or more selected from the group consisting of a cobalt-based catalyst and a manganese-based catalyst.
10. The oxidation of 5-hydroxymethylfurfural in step d is carried out in contact with an oxidizing gas in the presence of a catalyst containing one or more metal elements selected from Groups 8 to 11 of the periodic table. Item 10. The method for producing 5-hydroxymethylfurfural oxide according to any one of Items 7 to 9.
11. The catalyst contains one or more metal elements selected from the group consisting of ruthenium, rhodium, palladium, osmium, iridium, platinum, gold, and cobalt, and tin, bismuth, selenium, tellurium, as the second metal, The method for producing an oxide of 5-hydroxymethylfurfural according to claim 10, comprising at least one element selected from the group consisting of: and antimony.
12. 5-hydroxymethylfurfural oxide is 2,5-furandicarboxylic acid, diformylfuran, 2-carboxy-5-formylfuran, 5-hydroxymethyl-2-furancarboxylic acid, and 5-acetoxymethyl-2-furan The method for producing 5-hydroxymethylfurfural oxide according to any one of claims 6 to 11, which is one or more selected from the group consisting of carboxylic acids.