Preparation method of 5-hydroxymethylfurfural aqueous solution

Abstract

The invention discloses a preparation method of a 5-hydroxymethylfurfural aqueous solution, which comprises the following steps: directly mixing a solid-phase reaction system containing glycosyl biomass and a catalyst with an organic solvent phase, reacting in a reactor in a grinding state, and generating 5-hydroxymethylfurfural from the glycosyl biomass under the action of the catalyst, 5-hydroxymethylfurfural is transferred into an organic solvent phase in the ball milling process. And after the reaction, extracting the organic solvent phase after the reaction by using water as an extracting agent to obtain an aqueous solution of 5-hydroxymethylfurfural. The almost anhydrous reaction condition can effectively inhibit the generation of side reaction of the 5-hydroxymethylfurfural, the 5-hydroxymethylfurfural generated in the solid phase enters the organic solvent phase in time, the reaction selectivity is improved, the energy consumption in the production process is reduced, the aqueous solution of the 5-hydroxymethylfurfural is obtained through the aqueous phase extraction, and the method has the advantages of simple operation and low cost. High-energy-consumption operation processes such as reduced pressure distillation are not needed, and the organic solvent can be recycled.

Description

Technical Field

[0001] The present application relates to a method for preparing a 5-hydroxymethylfurfural aqueous solution, and belongs to the technical field of preparation and synthesis of 5-hydroxymethylfurfural. Background Art

[0002] Biomass materials can be obtained from biological resources, which are renewable and can be produced sustainably through agriculture, forestry and other planting activities without consuming non-renewable resources. This renewability makes biomass materials an environmentally friendly alternative. Biomass materials generally have a lower carbon footprint because they absorb carbon dioxide (CO2) from the atmosphere and store it in their tissues. In contrast, carbon dioxide released by fossil fuels can amplify the problem of global warming. Therefore, the use of biomass materials can help reduce greenhouse gas emissions and climate change. Many biomass materials have good biodegradability and can be naturally degraded and returned to the ecosystem. Compared with traditional plastics and synthetic materials, this property makes biomass materials have great potential in the fields of disposable products, packaging materials, etc., reducing the burden on landfills and pollution. Biomass materials have a wide range of applications in many fields. For example, in the fields of construction and decoration, biomass materials can be used to make floors, wall panels, furniture, etc. In the packaging industry, biomass materials can be used to produce degradable food packaging and disposable containers. In addition, biomass materials can also be used to produce textiles, biomedical materials, biofuels and chemicals, etc. Under the guidance of the "dual carbon goals", bio-based materials are gradually becoming one of the new industrial directions for global scientific and technological innovation and economic development. The bio-based chemical synthesis route using 5-hydroxymethylfurfural (HMF) as a platform compound and then converting it into other high-value-added derivatives is the future development direction.

[0003] The production process of 5-hydroxymethylfurfural is mainly to convert the pretreated biomass into the starting product of 5-hydroxymethylfurfural, namely glucose, by methods such as pyrolysis or acidolysis. This step can be achieved by heating the biomass with an acidic medium (such as sulfuric acid) to hydrolyze cellulose into glucose. Glucose is further converted into 5-hydroxymethylfurfural. This step involves an acid-catalyzed reaction, in which glucose undergoes a dehydration reaction under acidic conditions to produce 5-hydroxymethylfurfural. Commonly used acid catalysts include sulfuric acid, hydrochloric acid, phosphoric acid, etc. In order to improve the yield and selectivity, the reaction conditions need to be optimized. Factors such as reaction temperature, catalyst concentration, and reaction time can affect the generation rate and yield of 5-hydroxymethylfurfural. Related process research can be carried out through experiments and test optimization. After the synthesis reaction, 5-hydroxymethylfurfural needs to be separated and extracted from the reaction system. This can be done by methods such as solvent extraction, distillation, and crystallization. After extraction, purification processes such as crystallization, washing, and filtration can be used to obtain high-purity 5-hydroxymethylfurfural.

[0004] Although the process of catalytic conversion of carbohydrates is relatively mature, due to the high reactivity of 5-hydroxymethylfurfural, it is easy to further undergo side reactions in the water system to form polymers or black rot. The generation of these by-products will lead to low selectivity of the reaction, and will also cause corrosion and blockage of the equipment, making it difficult to clean, making it difficult to carry out the reaction, greatly increasing the maintenance and use costs of the equipment, and having poor economic benefits. 5-Hydroxymethylfurfural can be further deeply oxidized in the aqueous phase to prepare a bio-based raw material with important uses, furandicarboxylic acid. Therefore, the direct preparation of an aqueous solution of 5-hydroxymethylfurfural has great production and economic value, and does not require the traditional high energy consumption extraction and reduced pressure distillation operations to obtain 5-hydroxymethylfurfural crystals, which are then dissolved in the aqueous phase for deep oxidation. Summary of the invention

[0005] According to one aspect of the present application, a method for preparing an aqueous solution of 5-hydroxymethylfurfural is provided, which utilizes ball milling in a solid phase anhydrous system, and after the reaction is completed, 5-hydroxymethylfurfural in an organic solvent is extracted with water to obtain an aqueous solution of 5-hydroxymethylfurfural.

[0006] This application adopts the following technical solutions:

[0007] A method for preparing a 5-hydroxymethylfurfural aqueous solution comprises the following steps:

[0008] S1, mixing a solid phase reaction system containing sugar-based biomass and a catalyst with an organic solvent, grinding and reacting, and obtaining an organic solvent phase containing 5-hydroxymethylfurfural;

[0009] S2, extracting the organic solvent phase with water to obtain the 5-hydroxymethylfurfural aqueous solution.

[0010] Optionally, the water content of the solid phase reaction system is less than 1 wt %.

[0011] Optionally, the water content in the solid phase reaction system is less than 0.01 to 1 wt %.

[0012] Optionally, in the solid phase reaction system, except for the trace or trace amount of water carried by the sugar-based biomass and the catalyst itself or the catalyst itself being present in the form of an aqueous solution, no additional water is added.

[0013] The 5-hydroxymethylfurfural generated in the solid phase is transferred to the organic solvent phase during the reaction process. It can be dissolved in the organic solvent phase at the initial stage of 5-hydroxymethylfurfural generation, avoiding the side reaction of 5-hydroxymethylfurfural in the aqueous system, and inhibiting the side reaction of generating black rot. At the same time, the solid phase and the organic solvent phase are in direct contact in the system, and the water content in the system is low, so that the 5-hydroxymethylfurfural can be effectively avoided from further side reactions, and the discharge of sewage and wastewater in the system can be reduced. The aqueous solution of 5-hydroxymethylfurfural is obtained by aqueous phase extraction, and the organic solvent can be reused without the high-energy consumption operation process such as vacuum distillation. The system for synthesizing 5-hydroxymethylfurfural used in the present method has greater economic benefits, lower system cost, less environmental pollution, simple operation, easy to repeat, low equipment maintenance cost, and can efficiently produce 5-hydroxymethylfurfural aqueous solution.

[0014] Optionally, the weight ratio of the sugar-based biomass, the organic solvent, and the catalyst is 1:(1-100):(0.001-0.05).

[0015] Optionally, the weight ratio of the glycosyl biomass to the organic solvent is selected from any value of 1:1, 1:10, 1:20, 1:30, 1:40, 1:50, 1:60, 1:70, 1:80, 1:90, 1:95 or any range therebetween.

[0016] Optionally, the weight ratio of the glycosyl biomass to the catalyst is selected from any value of 1:0.1, 1:0.2, 1:0.5, 1:0.8, 1:0.1, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5 or any range therebetween.

[0017] Optionally, the grinding reaction conditions include: reaction temperature of 30 to 180° C., and reaction time of 2 to 10 h.

[0018] Optionally, the conditions of the grinding reaction include: the reaction temperature is selected from any value of 30°C, 40°C, 50°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 175°C, 180°C or any range therebetween; the reaction time is selected from any value of 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h or any range therebetween.

[0019] Optionally, the sugar-based biomass is selected from at least one of glucose, fructose, xylose, mannose, galactose, lactose, sucrose, maltose, cellulose and starch;

[0020] Optionally, the cellulose is selected from at least one of cellulose ether, methyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl cellulose and carboxymethyl cellulose.

[0021] Optionally, the organic solvent is selected from at least one of isobutyl acrylate, butyl propionate, butyl butyrate, ethyl isobutyrate, ethyl lactate, butyl lactate, amyl lactate, diethyl maleate, dibutyl maleate, soybean oil, sunflower oil, sesame oil, peanut oil, olive oil, castor oil, cottonseed oil, and isopropyl palmitate.

[0022] Optionally, the catalyst is selected from at least one of a water-soluble acid, a solid acid catalyst, an ionic liquid, an alkoxyaluminum, a phenoxyaluminum, tetrabutyl stannate, an alkoxytitanium, an alkoxyzirconium, ethyl antimonite, butyl antimonite, a halogen compound, a boride, a silicate, an aluminate, a phosphate, and a borate;

[0023] Optionally, the water-soluble acid is selected from at least one of phosphoric acid, hydrochloric acid, sulfuric acid, boric acid, and p-toluenesulfonic acid;

[0024] Optionally, the solid acid catalyst is selected from at least one of a cation exchange resin, a molecular sieve having an acidic site, a sulfide, a natural clay mineral, an amorphous oxide, and a metal organic framework material;

[0025] Optionally, the ionic liquid is selected from at least one of imidazole ionic liquids, pyridine ionic liquids, quaternary ammonium salt ionic liquids, and quaternary phosphonium salt ionic liquids.

[0026] Optionally, the hydrochloric acid is a 35.0-40.0 wt % hydrochloric acid solution.

[0027] Optionally, the sulfuric acid is 95.0-99.0 wt % concentrated sulfuric acid.

[0028] Optionally, the cation exchange resin is selected from sulfonic acid resins.

[0029] Optionally, the molecular sieve having an acidic site is selected from at least one of ZSM-5 molecular sieve, TS-1 molecular sieve, 13X molecular sieve and Y molecular sieve.

[0030] Optionally, the natural clay mineral is selected from kaolin.

[0031] Optionally, the halogen compound includes at least one of sodium chloride, sodium fluoride, magnesium chloride, calcium chloride, barium chloride, chromium chloride, ferric chloride, copper chloride, aluminum chloride, sodium bromide, calcium bromide and magnesium bromide.

[0032] Optionally, the boride includes at least one of boron fluoride, magnesium boride, titanium boride, chromium boride and calcium boride.

[0033] Optionally, the silicate includes at least one of sodium silicate, calcium silicate, magnesium silicate, ammonium silicate and the like.

[0034] Optionally, the aluminate includes at least one of sodium aluminate, calcium aluminate, magnesium aluminate, ammonium aluminate and the like.

[0035] Optionally, the phosphate includes at least one of sodium phosphate, calcium phosphate, magnesium phosphate, ammonium phosphate and the like.

[0036] Optionally, the metal organic framework material is selected from metal organic framework material MIL-125;

[0037] Optionally, the ionic liquid is selected from at least one of 1-hydroxyethyl-3-methylimidazolium chloride, 1-hydroxyethyl-3-methylimidazolium p-toluenesulfonate, 1-hydroxyethyl-2,3-dimethylimidazolium chloride, 1-hydroxyethyl-2,3-dimethylimidazolium p-toluenesulfonate, 1-hydroxyethyl-2,3-dimethylimidazolium nitrate, and 1-hydroxyethyl-2,3-dimethylimidazolium hexafluorophosphate.

[0038] Optionally, in step S1, the grinding reaction is carried out by ball milling;

[0039] Optionally, the reaction is carried out in a reactor; the reactor comprises a rotary ball mill reactor. Optionally, the ball milling rate is 5 to 1000 r / min.

[0040] Optionally, the ball milling rate is selected from any value of 5r / min, 50r / min, 150r / min, 200r / min, 300r / min, 500r / min, 600r / min, 800r / min, 1000r / min or any range therebetween.

[0041] Optionally, the reaction pressure is not particularly limited and may be at normal pressure.

[0042] Optionally, in step S2, the volume ratio of water to the organic solvent phase is 1 to 3:1.

[0043] Optionally, in step S2, the volume ratio of water to the organic solvent phase is any value of 1:1, 1.5:1, 2:1, 2.5:1, 5:1, or any range therebetween.

[0044] Optionally, the extraction is performed 2 to 5 times.

[0045] The extraction 2 to 5 times refers to adding water to the organic solvent phase obtained after the reaction for extraction, and after standing and shaking, the solution is separated into layers. After the water phase is separated, water is added again to the remaining organic solvent phase for extraction, and the operation is repeated multiple times.

[0046] Optionally, in the preparation method, the yield of 5-hydroxymethylfurfural in an organic solvent is greater than 80%.

[0047] Optionally, in the preparation method, the extraction efficiency of 5-hydroxymethylfurfural in the organic solvent after the water extraction reaction is 80% to 95%.

[0048] The beneficial effects of this application include:

[0049] (1) The present application provides a method for preparing an aqueous solution of 5-hydroxymethylfurfural. Compared with the traditional method of a simple aqueous phase reaction system, the preparation process of the present application has a low cost for obtaining a wide range of glycosyl biomass, and there is no aqueous phase, which avoids the phenomenon that 5-hydroxymethylfurfural is more likely to polymerize in the aqueous phase to produce black rot, and has a high conversion rate and selectivity. The solid phase reaction system is directly mixed with the organic solvent extraction phase by ball milling to produce a synergistic effect, and the product is transferred from the solid phase to the organic solvent phase, which can effectively control the occurrence of side reactions, avoid the production of black rot, improve the selectivity of the reaction, and greatly reduce equipment maintenance and labor costs.

[0050] (2) The present application provides a method for preparing a 5-hydroxymethylfurfural aqueous solution. After the reaction is completed, 5-hydroxymethylfurfural in the organic solvent phase of the reaction is extracted with water to obtain a 5-hydroxymethylfurfural aqueous solution. The organic solvent can be reused without the need for energy-intensive vacuum distillation operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 This is the hydrogen nuclear magnetic spectrum of the product synthesized in Example 1 of the present application.

[0052] Figure 2 This is the hydrogen nuclear magnetic spectrum of 5-hydroxymethylfurfural standard.

[0053] Figure 3 This is the carbon nuclear magnetic resonance spectrum of the product synthesized in Example 1 of the present application.

[0054] Figure 4 This is the carbon NMR spectrum of 5-hydroxymethylfurfural standard. DETAILED DESCRIPTION

[0055] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0056] Unless otherwise specified, the raw materials and catalysts in the examples of this application were purchased through commercial channels.

[0057] The analysis method in the examples of this application is as follows:

[0058] Carbon and hydrogen nuclear magnetic spectra were analyzed using a liquid nuclear magnetic spectrometer, model AVANCE II 400M, produced by Bruker Corporation, and the reaction solution was dissolved in a deuterated reagent.

[0059] The 5-hydroxymethylfurfural yield is detected by high performance liquid chromatography, and deionized water is added to mix and constant volume during the detection.

[0060] In the examples of the present application, the yield of 5-hydroxymethylfurfural is calculated in the following manner:

[0061] The liquid chromatography peak area is obtained by configuring the 5-hydroxymethylfurfural content in the standard solution, and the peak area is used as the abscissa and the concentration of 5-hydroxymethylfurfural is used as the ordinate to obtain a standard curve; further, the concentration of 5-hydroxymethylfurfural in the reaction solution after the reaction can be calculated, and the yield of 5-hydroxymethylfurfural can be calculated through the concentration.

[0062] In the examples of the present application, the concentrations of concentrated sulfuric acid and hydrochloric acid used are described as follows:

[0063] Concentrated sulfuric acid: H2SO4 is 98.0wt%;

[0064] Hydrochloric acid: HCl is 37.0 wt%.

[0065] The yield, selectivity and extraction efficiency of 5-hydroxymethylfurfural in the examples of the present application are calculated as follows:

[0066] Yield of 5-hydroxymethylfurfural = number of moles of 5-hydroxymethylfurfural produced / number of moles of reaction substrate added

[0067] Selectivity of 5-hydroxymethylfurfural = number of moles of 5-hydroxymethylfurfural produced / number of moles of reaction substrate involved in the reaction

[0068] The extraction efficiency of 5-hydroxymethylfurfural = the number of moles of 5-hydroxymethylfurfural in the aqueous solution / the number of moles of 5-hydroxymethylfurfural in the organic solvent phase before extraction.

[0069] Example 1

[0070] Add 5g glucose and 16.84g soybean oil to the ball mill reactor, add 0.12g concentrated sulfuric acid as a catalyst under stirring, heat to 120℃, react for 4 hours, and the ball mill speed is 35r / min. The color of the organic extract phase gradually deepens. After the reaction, a small amount of organic solvent phase was taken for high performance liquid chromatography analysis. The results showed that the yield of 5-hydroxymethylfurfural was 83% and the selectivity was 90%. Water (the volume ratio of water to reaction liquid was 2:1) was used in the organic solvent phase after the reaction for multiple extraction operations. The number of extractions was 4 times. After the extraction was completed, the extract was obtained. The extraction efficiency was 93%, and the obtained 5-hydroxymethylfurfural aqueous solution was obtained.

[0071] Example 2

[0072] 8g of methyl cellulose and 30g of isobutyl acrylate were added to an intermittent reactor, and 0.5g of ZSM-5 molecular sieve was added as a catalyst under stirring. The temperature was raised to 120°C, the reaction time was 5 hours, the ball mill speed was 150r / min, and the color of the organic extract phase gradually deepened. The color of the organic extract phase gradually deepened. After the reaction, a small amount of organic solvent phase was taken for high performance liquid chromatography analysis. The results showed that the yield of 5-hydroxymethylfurfural was 88% and the selectivity was 85%. Water (the volume ratio of water to reaction liquid was 3:1) was used in the organic solvent phase after the reaction for multiple extraction operations. The number of extractions was 3 times. After the extraction was completed, an extract was obtained with an extraction efficiency of 92%. The obtained 5-hydroxymethylfurfural aqueous solution was obtained.

[0073] Embodiments 3 to 11

[0074] The specific ingredient types, materials and reaction conditions are shown in Table 1 below. Other operations during the synthesis process are the same as in Example 1.

[0075] Table 1 Raw material composition, ratio and water extraction conditions of Examples 3 to 11

[0076]

[0077] Example 12 Liquid NMR Analysis

[0078] Liquid nuclear magnetic resonance analysis was performed on the 5-hydroxymethylfurfural prepared in Examples 1 to 11. Typical results are as follows: Figure 1 and Figure 3 As shown, Figure 2 and Figure 4 This is the standard spectrum of 5-hydroxymethylfurfural. Figure 1 The hydrogen nuclear magnetic resonance spectrum of 5-hydroxymethylfurfural prepared in Example 1 is as follows: Figure 1 and Figure 2 It can be seen from the comparison that the 5-hydroxymethylfurfural prepared in Example 1 has a typical standard 5-hydroxymethylfurfural hydrogen nuclear magnetic resonance spectrum.

[0079] Figure 3 The carbon nuclear magnetic resonance spectrum of 5-hydroxymethylfurfural prepared in Example 1 is as follows: Figure 3 and Figure 4 It can be seen from the comparison that the 5-hydroxymethylfurfural prepared in Example 1 has a typical standard 5-hydroxymethylfurfural carbon nuclear magnetic resonance spectrum.

[0080] The test results of 5-hydroxymethylfurfural in other embodiments are similar to those described above, and standard 5-hydroxymethylfurfural is obtained through the present application.

[0081] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for preparing a 5-hydroxymethylfurfural aqueous solution, characterized in that: The steps include: S1, mixing a solid phase reaction system containing sugar-based biomass and a catalyst with an organic solvent, grinding and reacting, and obtaining an organic solvent phase containing 5-hydroxymethylfurfural; S2, extracting the organic solvent phase with water to obtain the 5-hydroxymethylfurfural aqueous solution.

2. The preparation method according to claim 1, characterized in that: The water content of the solid phase reaction system is less than 1 wt %.

3. The preparation method according to claim 1, characterized in that: The weight ratio of the sugar-based biomass, the organic solvent and the catalyst is 1:(1-100):(0.001-0.05).

4. The preparation method according to claim 1, characterized in that: The grinding reaction conditions include: reaction temperature of 30 to 180° C., and reaction time of 2 to 10 hours.

5. The preparation method according to claim 1, characterized in that: The sugar-based biomass is selected from at least one of glucose, fructose, xylose, mannose, galactose, lactose, sucrose, maltose, cellulose and starch; Preferably, the cellulose is selected from at least one of cellulose ether, methyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl cellulose and carboxymethyl cellulose.

6. The preparation method according to claim 1, characterized in that: The organic solvent is selected from at least one of isobutyl acrylate, butyl propionate, butyl butyrate, ethyl isobutyrate, ethyl lactate, butyl lactate, amyl lactate, diethyl maleate, dibutyl maleate, soybean oil, sunflower oil, sesame oil, peanut oil, olive oil, castor oil, cottonseed oil, and isopropyl palmitate.

7. The preparation method according to claim 1, characterized in that: The catalyst is selected from at least one of a water-soluble acid, a solid acid catalyst, an ionic liquid, an alkoxy aluminum, a phenoxy aluminum, tetrabutyl stannate, an alkoxy titanium, an alkoxy zirconium, ethyl antimonite, butyl antimonite, a halogen compound, a boride, a silicate, an aluminate, a phosphate, and a borate; Preferably, the water-soluble acid is selected from at least one of phosphoric acid, hydrochloric acid, sulfuric acid, boric acid, and p-toluenesulfonic acid; Preferably, the solid acid catalyst is selected from at least one of a cation exchange resin, a molecular sieve having an acidic site, a sulfide, a natural clay mineral, an amorphous oxide, and a metal organic framework material; Preferably, the ionic liquid is selected from at least one of imidazole ionic liquids, pyridine ionic liquids, quaternary ammonium salt ionic liquids, and quaternary phosphonium salt ionic liquids.

8. The preparation method according to claim 7, characterized in that: The cation exchange resin is selected from sulfonic acid resin; Preferably, the molecular sieve having an acidic site is selected from at least one of ZSM-5 molecular sieve, TS-1 molecular sieve, 13X molecular sieve, and Y molecular sieve; Preferably, the natural clay mineral is selected from kaolin; Preferably, the metal organic framework material is selected from the metal organic framework material MIL-125; Preferably, the ionic liquid is selected from at least one of 1-hydroxyethyl-3-methylimidazolium chloride, 1-hydroxyethyl-3-methylimidazolium p-toluenesulfonate, 1-hydroxyethyl-2,3-dimethylimidazolium chloride, 1-hydroxyethyl-2,3-dimethylimidazolium p-toluenesulfonate, 1-hydroxyethyl-2,3-dimethylimidazolium nitrate, and 1-hydroxyethyl-2,3-dimethylimidazolium hexafluorophosphate.

9. The preparation method according to claim 1, characterized in that: In the step S1, the grinding reaction is carried out by ball milling; Preferably, the ball milling speed is 5 to 1000 r / min.

10. The preparation method according to claim 1, characterized in that: In the step S2, the volume ratio of water to the organic solvent phase is 1 to 3:1; Preferably, the extraction is performed 2 to 5 times.

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