JP2018090511A - Method for producing furan derivative - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for easily obtaining furan derivative using unpurified hydroxymethylfurfural and/or furfural without purification when carrying out oxidation reaction or reduction reaction in which hydroxymethylfurfural and/or furfural obtained by reacting saccharides such as cellulose, starch, glucose, fructose or the like is a raw material.SOLUTION: In the method, a corresponding compound is easily obtained by oxidation reaction or reduction reaction without purification by removing reaction inhibiting impurities by adding adsorbent such as alumina to biomass-derived hydroxymethyl-furfural solution or furfural solution.SELECTED DRAWING: None

Description

  The present invention relates to a method for producing a furan derivative using furfurals obtained from sugars as a raw material.

  In recent years, global warming has become a global problem, and the development of technologies that utilize biomass as carbon neutral resources and renewable resources is being actively promoted.

  Furfurals are compounds obtained from polysaccharides such as cellulose, hemicellulose and starch, or saccharides such as glucose, xylose and fructose among substances derived from biomass, and particularly from glucose and fructose, the following formula (1 ) (Hereinafter sometimes referred to as “HMF”), and the fact that furfural represented by the following formula (2) is obtained from xylose has already been reported in many literatures. (Patent Document 1).

Biomass-derived furfurals are one of the important candidate compounds for petroleum substitutes that can be used as intermediate raw materials for resins, chemical products, fuels and the like.
For example, in the case of furfural, a method of converting to 2-furfuryl alcohol to use as a raw material for furan resin, a method of converting to furan by a decarbonylation reaction, and then hydrogenating to furan to form tetrahydrofuran is known.
In HMF, a method of reacting 2,5-diformylfuran or 5-formylfuran-2-carboxylic acid obtained by oxidation with a long-chain amine to form a surfactant, or by oxidizing A method using the obtained furan-2,5-dicarboxylic acid or 2,5-bis (hydroxymethyl) furan obtained by selective hydrogenation as a raw material for polyamide, polyester, polyurethane, or the like, or 2,5-bis ( There are known methods such as dimethylfuran obtained by hydrogenolysis of hydroxymethyl) furan or dimethylfuran obtained by direct hydrogenation and hydrogenolysis from HMF, as an alternative to gasoline.

  Compounds such as HMF and furfural obtained from such biomass coexist as impurities such as organic acids such as formic acid and acetic acid, insoluble humic substances, unreacted saccharides, etc. generated during synthesis. It cannot be used for conversion to useful compounds by various reactions such as hydrogenation, hydrogenolysis, esterification, etc., and it is difficult to store for a long time because it decomposes or polymerizes during storage. is necessary.

However, in the purification of HMF, in particular, when water is used as a solvent during the synthesis reaction of HMF, it is difficult to take out HMF from the reaction solution and purify it, and a lot of HMF produced during the purification is often lost.
A plurality of methods for purifying HMF have been reported, but since HMF has a hydroxyl group substituted in the molecule, a reaction such as polymerization easily occurs by heating or the like. Therefore, methods such as distillation cannot be used.

Thus, in Patent Document 2, acetic anhydride is added to the reaction solution as it is to acylate the hydroxyl group, and then a clean HMF is obtained by deacetylating the separated and purified acyl form. Therefore, the purity of HMF is 99% or more, but the yield from the starting material D-fructose is as low as 28%.
Patent Document 3 describes a method of purification by extraction. That is, the reaction solution is filtered to produce water-insoluble impurities, which are anhydrides and sugar condensates due to intermolecular dehydration of sugars, polycondensation products of purified HMFs, and further HMFs, sugars, and reactions. It is considered to be a generic humic substance that is thought to be obtained from intermediates and products obtained by further reacting HMF. After removing these, a hydrophobic solvent is added to the reaction solution by utilizing the fact that HMF is amphiphilic. The HMF is extracted from a reaction solution of HMF obtained with a relatively high selectivity with an HMF purity of 60% or more, and the solvent is distilled off. Then, distilled water, ion-exchanged water or pure water is added to the extract containing HMF. Water is added, and a hydrophobic solvent is added again for extraction and purification. This method can be applied only when the solvent distills out under reduced pressure or takes time, HMF is originally only from a relatively high purity reaction solution, and the final purity of HMF is improved only to about 90%. Can not. Therefore, there is no difference from a general method for purifying organic compounds in that pure HMF requires further operations such as recrystallization, distillation and purification by column chromatography.

  Furthermore, in Patent Document 4, oxidation is performed using a solution after extracting the synthesized HMF with water and replacing the solvent, but this is a technique that can be applied because the purity of HMF is 90% or higher. In the case of HMF with low purity containing humic substances, or HMF that has generated impurities due to long-term storage, etc., oxidation reaction inhibition occurs due to catalyst poisoning by humic substances in the next oxidation step. These are difficult to use.

  Further, in Patent Document 5, furan-2,5-dicarboxylic acid is produced by oxidizing a hydroxymethylfurfural mixture obtained by dehydration reaction of sugars with permanganate in an alkaline environment without separation and purification. However, a large amount of alkali is added to oxidize with a very strong oxidizing agent, and permanganate becomes manganese dioxide after the oxidation reaction, resulting in a large amount of waste. Moreover, although it is suitable for manufacture other than furan-2,5-dicarboxylic acid, it is not suitable for manufacture of 2,5-diformylfuran or 5-formylfuran-2-carboxylic acid.

  Various compounds are synthesized using this purified HMF and furfural. For example, in Patent Document 6, 2,5-diformylfuran is produced from HMF using oxygen as an oxidizing agent in the presence of a catalyst. In Patent Document 7, 2,5-diformylfuran is produced from HMF using an oxidant in the presence of a catalyst. Since all of them use purified HMF, there is an industrial process for purifying HMF. It was a factor of cost improvement.

In general, as shown in Non-Patent Document 1, a method for producing 2,5-diformylfuran from HMF using manganese dioxide or chromium trioxide as an oxidizing agent is disclosed.
However, since purified HMF is used, it is disadvantageous in terms of cost from the price of HMF as a raw material.

US Patent Application Publication No. 2008/0103318 US Patent Application Publication No. 2008/0200698 JP2013-203665A JP 2013-203666 A JP 2007-261990 A Special table 2003-528868 gazette Japanese Patent Application No. 2015-246219

Journal of the American Chemical Society, 1984, vol. 106, p. 7112

  In order to solve the above-mentioned problems, the present invention performs various synthetic reactions using unpurified furfurals without using purified furfurals such as HMF and furfural. It is a production method for easily obtaining a corresponding furan derivative such as diformylfuran and 2-furfuryl alcohol in a high yield and high selectivity, and further provides an easy purification method for the product. It is an object to provide a technique for significantly reducing the cost of synthesis into various compounds using a class.

  As a result of intensive studies to solve the above problems, the present inventors have found that furfurals immediately after synthesis from cellulose, starch, glucose, and fructose contain a lot of organic acids and humic substances. It has been found that it affects the next oxidation reaction and reduction reaction and gives complex products. As a result, adsorbents such as alumina are added to the synthesized aqueous solution, and only impurities that affect these reactions are adsorbed and filtered. Thus, it was found that the next reaction can be carried out without further purification of furfurals. Furthermore, when the adsorbent of alumina does not affect the next reaction, it can be found that a high-purity target can be easily synthesized by coexisting these adsorbents during the reaction, and the above object can be achieved. There was found.

The present invention has been completed based on these findings and is as follows.
[1] An adsorbent is added to a solution containing biomass-derived hydroxymethylfurfural and / or furfural to remove impurities, and then a solution obtained by separating and removing the adsorbent is used to produce a furan derivative. A method for producing a furan derivative.
[2] The method for producing a furan derivative according to [1], wherein the adsorbent is at least one selected from manganese oxide, alumina, silica, titania, magnesia, zirconia, and zeolite.
[3] The method for producing a furan derivative according to [1] or [2], wherein 2,5-diformylfuran is generated by an oxidation reaction of hydroxymethylfurfural.
[4] The method for producing a furan derivative according to [3], wherein oxygen is used as an oxidizing agent and ruthenium-supported alumina is used as a catalyst.
[5] The method for producing a furan derivative according to [3], wherein manganese dioxide is used as an oxidizing agent.
[6] The method for producing a furan derivative according to [1] or [2], wherein 2,5-bis (hydroxymethyl) furan is generated by a reduction reaction of hydroxymethylfurfural.
[7] The method for producing a furan derivative according to [1] or [2], wherein 2,5-dimethylfuran is generated by a reduction reaction of hydroxymethylfurfural.
[8] The method for producing a furan derivative according to [1] or [2], wherein 2-furfuryl alcohol is produced by a reduction reaction of furfural.
[9] The method for producing a furan derivative according to [1] or [2], wherein 2-methylfuran is generated by a reduction reaction of furfural.

  According to the method for producing a furan derivative of the present invention, by using an adsorbent such as alumina for crude furfurals that have not been synthesized and purified, organic acids and humic substances that are generated as impurities during synthesis can be removed. As a result, it is possible to suppress the influence on the next reaction as much as possible, so that the reaction can be carried out using crude furfurals in the same manner as in the case of using purified furfurals. A furan derivative can be obtained with an equivalent selectivity and yield.

  Hereinafter, the present invention will be described in detail.

  The furfurals used in the present invention are biomass-derived compounds made from polysaccharides such as cellulose, hemicellulose, and starch, or sugars such as glucose, xylose, and fructose, and are typically hydroxymethylfurfural (HMF). ) And furfural.

In addition, the furfural is contained in HMF synthesize | combined with biomass. This is because furfural is derived from xylose, which is a monosaccharide from xylan, which is a component of hemicellulose, which is the same class of glucose, which is a monosaccharide of biomass cellulose.
Since furfural has no hydroxyl group, it does not proceed to the oxidation reaction. However, according to the method of the present invention, impurities such as humic substances are removed, so that the crude furfural contained in the crude HMF is also purified furfural. It can be used for the reduction reaction in the same manner as.

  The adsorbent used in the present invention is a solid adsorbent such as alumina that can be easily separated by filtration.

  Examples of the adsorbent used in the present invention include carbon, alumina, silica, zirconia, titania, tin oxide, strontium oxide, calcium oxide, iron oxide, manganese oxide, vanadium oxide, cobalt oxide, copper oxide, zinc oxide, zeolite, and montmorillonite. , Molecular sieves, hydroxyapatite and the like, alumina, zirconia, titania, manganese oxide and zeolite are preferred, and alumina, zeolite and manganese oxide are most preferred.

  The amount of the adsorbent used in the present invention is not particularly limited, and the amount by which impurities contained in the crude HMF solution are sufficiently adsorbed can be determined as appropriate.

  After the adsorbent is added, the adsorbent can be easily separated from the system by filtration, and can be used again as an adsorbent after washing, drying and firing.

The crude HMF solution from which impurities are removed with the adsorbent used in the present invention is a method for producing 2,5-diformylfuran represented by the following formula (3) by an oxidation reaction, and further, the following formula is obtained by oxidation. A method for producing furan-2,5-dicarboxylic acid represented by (4), or a method for producing 2,5-bis (hydroxymethyl) furan represented by the following formula (5) by a reduction reaction; Furthermore, it can be used in a method for producing 2,5-dimethylfuran represented by the following formula (6) by reduction.
In addition, the crude flural solution from which impurities have been removed by the adsorbent used in the present invention is a method for producing 2-furfuryl alcohol represented by the following formula (7) by a reduction reaction, and further reduced to the following. It can be used in a method for producing 2-methylfuran represented by the formula (8).

  The adsorbent used in the present invention can be used for removing impurities from the crude furfurals, but can be added to the previous reaction system to carry out the reaction if it does not affect the reaction.

  Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto. The reaction conversion and yield were determined by the following method.

<Conversion rate>
The conversion rate was determined by the following method.
After calculating | requiring the density | concentration of HMF or a furfural using the analytical curve prepared beforehand from the peak area of HMF or a furfural contained in each crude HMF liquid or a rough furfural liquid with the synthesized reaction liquid, The number of moles of total HMF or furfural contained in the solution was determined. Next, from the solution after the reaction, similarly, the concentration of HMF or furfural is obtained using liquid chromatography, the number of moles of HMF or furfural remaining in the solution after the reaction is obtained, and the remaining amount relative to the number of moles of HMF or furfural used. The percentage of moles of HMF or furfural was taken as the recovery rate. Finally, the difference in recovery from 100% was taken as the conversion rate.
Conversion rate (%) = 100 (%)-recovery rate (%)

<yield>
The yield was determined by the following method.
The number of moles of the target product remaining in the reaction solution was determined from liquid chromatography, and the percentage of the number of moles of the target product obtained relative to the number of moles of HMF or furfural used was defined as the yield.
Yield (%) = number of moles of target product / number of moles of HMF or furfural used × 100 (%)

<Selectivity>
The selectivity was the percentage of the yield of the target product relative to the conversion of HMF or furfural.
Selectivity (%) = target product yield / conversion rate of HMF or furfural × 100 (%)

Example 1
A crude HMF solution (HMF selectivity 30%, HMF-containing concentration 0.1-0.2 M, 400 mL) is obtained by reacting glucose (0.5 mol / L) in a water-butanol mixture (containing 5% butanol) in a flow-through manner. Got. The obtained solution was salted out with sodium chloride, and humic substances were removed by filtration. 400 mL of ethyl acetate was added to the filtrate to extract HMF. The extraction rate was 90%. Moreover, the HMF purity measured by gas chromatography of this extract was improved to about 60 to 80% except when activated carbon or celite was used.
Each adsorbent (100 mg) was added to this extract (1 mL), and the degree of impurity removal was evaluated visually by the degree of decolorization of the extract. Those having a high degree of decolorization were rated as 〇 for those that were particularly good with ◯, and those that were hardly decolored as x.

As a result, it was found that manganese dioxide, alumina, silica, titania, magnesia, zirconia, and zeolite showed good results.
The results are shown in the following table.

(Example 2)
The crude HMF (2.0 g) obtained after distilling off the solvent from the ethyl acetate solution containing crude HMF from which impurities were removed with alumina was placed in a reaction vessel, manganese dioxide was added as an oxidizing agent, and oxidation was performed in a dichloromethane solution. Reaction was performed. After the reaction, the reaction solution was filtered. When the light yellow filtrate was evaporated, a light yellow solid was obtained. The obtained solid was 2,5-diformylfuran and had a purity of 93%. Furthermore, white 2,5-diformylfuran (purity 99% or more) was obtained by performing recrystallization. The yield of 2,5-diformylfuran from HMF was 99% or more, and it was found that the subsequent reaction was equivalent to purified HMF by removing impurities.

(Example 3)
Crude HMF (0.28 g) obtained after distilling off the solvent from the ethyl acetate solution containing crude HMF from which impurities were removed with alumina was placed in a reaction vessel, toluene (5 mL) was added, and 5 wt% ruthenium-supported alumina as a catalyst. And suspended. A gas collection bag filled with oxygen gas was attached to the reaction vessel, and the inside of the reaction vessel was purged with oxygen using an aspirator. After the reaction solution was reacted at 80 ° C. for 42 hours with vigorous stirring, the catalyst was removed by filtration, and the mother liquor was distilled off under reduced pressure to obtain a pale yellow solid. As a result of analyzing the obtained product, the raw material was completely lost, and the yield of the desired 2,5-diformylfuran was 99% or more.
In addition, instead of alumina, when an oxidation reaction was attempted under the same conditions using manganese oxide, silica, titania, zirconia, zeolite, activated carbon, or crude HMF from which impurities were removed with zeolite, the removal was performed with activated carbon and zeolite. The yield of the target 2,5-diformylfuran was 99% or more (see [Table 1] above).

Example 4
100 mg of crude HMF obtained after distilling off the solvent from the ethyl acetate solution containing crude HMF from which impurities were removed with alumina was placed in a reaction vessel, added with 2 mL of water, and suspended by adding 5 wt% platinum-supported mesoporous silica as a catalyst. It was. The inside of the reaction vessel was pressurized to 0.8 MPa with hydrogen gas, and then reacted at 35 ° C. for 2 hours. After the reaction, the catalyst was removed by filtration, the filtrate was distilled off under reduced pressure, and the components obtained by chromatography were analyzed. The conversion was 99% or more and 2,5-bis (hydroxy) represented by the following formula: It was found that methyl) furan was obtained with a selectivity of 98% and a yield of 98%.

  Further, when the reaction was carried out under the same conditions using furfural as a raw material, the conversion rate was 99% or more, and the selectivity for furfuryl alcohol (2-hydroxymethylfuran) represented by the following formula was 95%. Met.

(Example 5)
Under the same conditions as in Example 4, using 100 mg of crude HMF from which impurities were removed using alumina, 5 wt% palladium-supported carbon was placed in the reaction vessel as a catalyst, 1 mL of water was added, and the inside of the reaction vessel was filled with hydrogen gas. After pressurizing to 1 MPa, 10 MPa of carbon dioxide was added and reacted at 80 ° C. for 2 hours. After the reaction, the catalyst was removed by filtration, and the components obtained by chromatography of the filtrate as they were were analyzed. As a result, the conversion was 99% or more and 2,5-dimethylfuran was obtained 99% or more.

  Further, when furfural was performed under the same conditions, the conversion rate was 99% or more, and the yield and selectivity of 2-methylfuran represented by the following formula were both 99% or more.

(Comparative Example 1)
Manganese dioxide was added as an oxidizing agent to HMF purchased from a reagent company (Aldrich, purity 98%, 100 mg), and an oxidation reaction was performed in a dichloromethane solution. After the reaction, the reaction solution was filtered and the filtrate was evaporated to obtain a pale yellow solid. The resulting solid was 2,5-diformylfuran and the purity was 95%. The yield of 2,5-diformylfuran from HMF was 99% or more.

(Comparative Example 2)
Toluene (5 mL) was added to HMF purchased from a reagent company (Aldrich, purity 98%, 98 mg), and 5 wt% ruthenium-supported alumina was suspended as a catalyst. A gas collection bag filled with oxygen gas was attached, and the inside of the reaction vessel was purged with oxygen using an aspirator. The reaction solution was reacted at 80 ° C. for 24 hours with vigorous stirring, then the catalyst was removed by filtration, and the mother liquor was evaporated under reduced pressure. As a result of analyzing the obtained product, the raw material was completely lost, and the yield of the desired 2,5-diformylfuran was 98%.

(Comparative Example 3)
When the HMF solution obtained without adding an adsorbent such as alumina was concentrated and stored in a refrigerator (10 ° C.), the HMF disappeared with the passage of time, and the HMF that was about 30% disappeared after one month. Therefore, the oxidation reaction could not be performed. At room temperature (28 ° C.), 45% of HMF disappeared after 2 days.

Claims (9)

  A furan derivative is produced using a solution obtained by separating and removing an adsorbent after adding an adsorbent to a solution containing biomass-derived hydroxymethylfurfural and / or furfural to remove impurities. A method for producing a furan derivative.   2. The method for producing a furan derivative according to claim 1, wherein the adsorbent is at least one selected from manganese oxide, alumina, silica, titania, magnesia, zirconia, and zeolite.   The method for producing a furan derivative according to claim 1 or 2, wherein 2,5-diformylfuran is produced by an oxidation reaction of hydroxymethylfurfural.   The method for producing a furan derivative according to claim 3, wherein oxygen is used as an oxidizing agent and ruthenium-supported alumina is used as a catalyst.   4. The method for producing a furan derivative according to claim 3, wherein manganese dioxide is used as an oxidizing agent.   The method for producing a furan derivative according to claim 1 or 2, wherein 2,5-bis (hydroxymethyl) furan is produced by a reduction reaction of hydroxymethylfurfural.   The method for producing a furan derivative according to claim 1 or 2, wherein 2,5-dimethylfuran is produced by a reduction reaction of hydroxymethylfurfural.   The method for producing a furan derivative according to claim 1 or 2, wherein 2-furfuryl alcohol is produced by a reduction reaction of furfural.   The method for producing a furan derivative according to claim 1 or 2, wherein 2-methylfuran is produced by a reduction reaction of furfural.