Method for preparing 2, 5-furandicarboxaldehyde from fructose through one-pot one-step method

Abstract

The invention provides a method for preparing 2, 5-furandicarboxaldehyde from fructose through a one-pot one-step method, which comprises the following steps: in an air atmosphere, by taking fructose as a raw material, adding an HCP-AQ-Mo-SO3H catalyst, heating and reacting in dimethyl sulfoxide at normal pressure, and dehydrating and oxidizing to obtain 2, 5-furandicarboxaldehyde; the HCP-AQ-Mo-SO3H catalyst can be repeatedly used after being filtered, separated and washed. According to the catalyst, fructose can be directly converted into DFF through dehydration and oxidation reactions in an air environment, reaction atmosphere does not need to be switched, and the operation convenience is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of bio-based polymer monomer preparation technology, and in particular to a one-pot, one-step method for preparing 2,5-furandicarboxaldehyde from fructose. Background Technology

[0002] In recent years, with the gradual depletion of traditional fossil fuels, renewable biomass energy has become the most ideal alternative. The conversion and utilization of biomass energy marks a significant step towards a sustainable energy transition. It is worth noting that biomass resources have many advantages over fossil resources, such as being renewable, widely available, and producing green carbon. Utilizing biomass to partially replace fossil resources can help alleviate some of the energy and environmental problems caused by the overconsumption of these non-renewable resources.

[0003] Lignin, an important component of biomass, has attracted much attention due to its abundant quantity, low cost, easy availability, and low pollution. It can be easily broken down and separated to obtain fructose, one of the six-carbon sugars. Fructose can then be converted into the chemical 5-hydroxymethylfurfural (HMF). Further conversion of HMF yields a series of high-value-added chemicals, including 2,5-furandicarboxaldehyde (DFF), 2,5-furandicarboxylic acid (FDCA), 2,5-furandiethanol (BHMF), and dimethyl 2,5-furandicarboxylate (DMFD). DFF can be used to prepare pharmaceutical intermediates, antibacterial agents, binders, and fluorescent agents, and also has applications in the research of macrocyclic ligands and organic conductors. Furthermore, DFF can be used to synthesize various novel polymer materials, such as biomass-based novel resins, fluorescent materials, polyols, and polyethylene.

[0004] Currently, there are two methods for converting fructose to dimethyl sulfoxide (DFF): one method involves first dehydrating fructose to generate a hydrogen sulfoxide (HMF) intermediate, which is then selectively catalytically oxidized to DFF. This method involves two independent reactions, which are cumbersome and have high production costs. The other method is a one-pot process that directly dehydrates and oxidizes fructose to obtain DFF. This method requires the reaction system to have both dehydration and oxidation capabilities.

[0005] Therefore, developing a bifunctional catalyst that has both dehydration and catalytic oxidation capabilities, enabling the direct conversion of fructose into DFF, is crucial for industrial production. This would improve operational convenience, reduce economic costs, and simplify the reaction process. Summary of the Invention

[0006] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a one-pot, one-step method for preparing 2,5-furandicarboxaldehyde from fructose, which solves the problems of the existing one-pot process for preparing DFF from fructose requiring N2 protection during the dehydration reaction and then being replaced with an O2 environment for catalytic oxidation after dehydration is completed, which is cumbersome and costly.

[0007] To achieve the above and other related objectives, this invention provides a one-pot, one-step method for preparing 2,5-furandicarboxaldehyde from fructose. In an air atmosphere, fructose is used as the raw material, and an HCP-AQ-Mo-SO3H catalyst is added. The reaction is carried out in dimethyl sulfoxide under normal pressure with heating to dehydrate and oxidize the fructose, yielding 2,5-furandicarboxaldehyde. The HCP-AQ-Mo-SO3H catalyst can be reused after filtration, separation, and washing.

[0008] Preferably, the HCP-AQ-Mo-SO3H catalyst is prepared by a method comprising the following steps: (1) 2-hydroxy-N-(quinoline-8-yl)benzamide, p-dichlorobenzyl and anhydrous ferric chloride are dispersed in a first organic solvent and heated in a nitrogen atmosphere. The solid and liquid are separated, the solid is washed and dried to obtain the macromolecular ligand HCP-AQ.

[0009] (2) The molybdenum acetylacetonate and the macromolecular ligand HCP-AQ were heated and reacted in a second organic solvent. The solid and liquid were separated and the resulting solid was washed to obtain HCP-AQ-Mo. (3) Chlorosulfonic acid and HCP-AQ-Mo are stirred and reacted in a third organic solvent at room temperature. The reaction mixture is poured into ice water, filtered and the solid is collected. It is first washed with water until the washing liquid is neutral, then washed three times with methanol. After drying, it is named HCP-AQ-Mo-SO3H, which is the HCP-AQ-Mo-SO3H catalyst.

[0010] The synthetic route of the HCP-AQ-Mo-SO3H catalyst is shown below: .

[0011] The HCP-AQ-Mo-SO3H catalyst was prepared by a method comprising the following steps: (1) 2-hydroxy-N-(quinoline-8-yl)benzamide, p-dichlorobenzyl, anhydrous ferric chloride and organic solvent were added to a reaction flask and reacted at a certain temperature under a nitrogen atmosphere. After the reaction was completed, the solid was collected by filtration and washed with a large amount of methanol until the washing liquid was colorless. Then, the solid was dried under vacuum to obtain the macromolecular ligand HCP-AQ.

[0012] (2) After heating the molybdenum acetylacetonate and the macromolecular ligand HCP-AQ prepared in the previous step in a solvent for a period of time, the solid was collected by filtration, washed with methanol three times, and the obtained solid was dried and recorded as HCP-AQ-Mo.

[0013] (3) Chlorosulfonic acid and HCP-AQ-Mo prepared in the previous step are stirred in dichloromethane for a period of time. The reaction mixture is poured into ice water, filtered and the solid is collected. It is first washed with water until the washing liquid is neutral, then washed three times with methanol. After drying, it is recorded as HCP-AQ-Mo-SO3H, which is the catalyst prepared.

[0014] Preferably, in step (1), the molar ratio of benzamide to dibenzyl chloride and anhydrous ferric chloride is 1:(1-3):(2-5); more preferably, it is 1:(1.15-1.6):(2.5-4).

[0015] Preferably, in step (1), the first organic solvent is selected from toluene, methanol, ethyl acetate, ethanol, dichloromethane and dichloroethane; more preferably, it is dichloroethane.

[0016] Preferably, in step (1), the heating temperature is 50-120°C, more preferably 80-100°C, and the reaction time is 10-30h, more preferably 18-24h.

[0017] Preferably, in step (2), the mass ratio of the macromolecular ligand HCP-AQ to molybdenum acetylacetone is 1:(1-3), more preferably 1:(1.2-2).

[0018] Preferably, in step (2), the second organic solvent is selected from toluene, methanol, ethyl acetate, ethanol and dichloromethane; more preferably, it is methanol.

[0019] Preferably, in step (2), the heating temperature is 50-100°C, more preferably 60-80°C, and the reaction time is 12-48h, more preferably 20-28h.

[0020] Preferably, in step (3), the mass ratio of HCP-AQ-Mo to chlorosulfonic acid is 1:(2-17), more preferably 1:(5-13).

[0021] Preferably, in step (3), the reaction time is 10 to 70 hours, more preferably 20 to 28 hours.

[0022] Preferably, in step (3), the third organic solvent is selected from toluene, methanol, ethyl acetate, ethanol and dichloromethane, more preferably dichloromethane.

[0023] Preferably, in step (3), the reaction time is 10 to 70 hours, and more preferably 30 to 50 hours.

[0024] Preferably, the mass ratio of the HCP-AQ-Mo-SO3H catalyst to fructose is 1:(2-6), more preferably 1:(5-13).

[0025] Preferably, the mass ratio of dimethyl sulfoxide to fructose is (10-25):1, more preferably (15-20):1.

[0026] Preferably, the heating reaction temperature is 120–160°C, more preferably 130–150°C, and the reaction time is 3–15 h, more preferably 8–12 h.

[0027] As described above, the present invention has the following beneficial effects: (1) The catalyst of this invention can realize the one-pot, one-step conversion of fructose directly into DFF through dehydration and oxidation reactions; (2) The present invention uses HCP-AQ-Mo-SO3H as a catalyst for the preparation of DFF from fructose, which has the characteristics of stable catalyst structure and simple separation and recovery. Attached Figure Description

[0028] Figure 1 The image shown is a scanning electron microscope (SEM) image of the HCP-AQ-Mo-SO3H catalyst prepared in Example 1.

[0029] Figure 2 The image shows the X-ray photoelectron spectroscopy (XPS) spectrum of the HCP-AQ-Mo-SO3H catalyst prepared in Example 1.

[0030] Figure 3 The image shows the X-ray diffraction (XRD) pattern of the HCP-AQ-Mo-SO3H catalyst prepared in Example 1.

[0031] Figure 4 The infrared spectrum (IR) of the HCP-AQ-Mo-SO3H catalyst prepared in Example 1.

[0032] Figure 5 The image shows the N2 adsorption-desorption isotherm (BET) of the HCP-AQ-Mo-SO3H catalyst prepared in Example 1. Detailed Implementation

[0033] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0034] It should be noted that the process equipment or apparatus not specifically mentioned in the following embodiments are all conventional equipment or apparatus in the art.

[0035] Furthermore, it should be understood that the existence of other method steps before or after the combined steps, or the insertion of other method steps between these explicitly mentioned steps, does not preclude the existence of other method steps before or after the combined steps, or the insertion of other method steps between these explicitly mentioned steps, unless otherwise stated. It should also be understood that the combined connection relationship between one or more devices / apparatus mentioned in this invention does not preclude the existence of other devices / apparatus before or after the combined devices / apparatus, or the insertion of other devices / apparatus between these explicitly mentioned devices / apparatus, unless otherwise stated. Moreover, unless otherwise stated, the numbering of each method step is merely a convenient tool for identifying each method step, and not for limiting the order of the method steps or limiting the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0036] Example 1 This application provides a method for preparing 2,5-furandicarboxaldehyde in a one-pot, one-step process from fructose, including the following steps: (1) 1.32 g of 2-hydroxy-N-(quinoline-8-yl)benzamide (5 mmol), 1.05 g of p-dichlorobenzyl (6 mmol), 2.445 g of anhydrous ferric chloride (15 mmol) and 40 mL of dichloroethane were added to a reaction flask and reacted at 90 °C for 20 h under a nitrogen atmosphere. After the reaction was completed, the solid was collected by filtration and washed with a large amount of methanol until the washing liquid was colorless. Then the solid was dried under vacuum at 80 °C to obtain the macromolecular ligand HCP-AQ; (2) Add 1.6 g of molybdenum acetylacetonate, 1.2 g of HCP-AQ obtained in the previous step, and 50 mL of methanol to a reaction flask and stir at 70 °C for 24 h. After the reaction is complete, filter and collect the solid, wash the solid three times with methanol, and dry the solid and label it as HCP-AQ-Mo; (3) Add 1.0 g of HCP-AQ-Mo, 5 mL of chlorosulfonic acid and 30 mL of dichloromethane obtained in the previous step to a reaction flask and stir at room temperature for 40 h. After the reaction is complete, slowly add the mixture to 300 mL of ice water. Filter to collect the solid, wash with water until the washing liquid is neutral, then wash with methanol three times, and dry the obtained solid under vacuum at 80 °C. This solid is designated as HCP-AQ-Mo-SO3H catalyst. (4) 180 mg fructose, 60 mg HCP-AQ-Mo-SO3H catalyst and 3 mL DMSO were added to a three-necked flask equipped with a magnetic stir bar and a thermometer, and the reaction was carried out at 140 °C for 10 h. After the reaction was completed, the yield of product DFF was 75% by gas chromatography with internal standard method.

[0037] The characterization results of the HCP-AQ-Mo-SO3H catalyst prepared in this embodiment are as follows: Figures 1-5 As shown: from Figure 1 It can be seen that the scanning electron microscope image of the prepared catalyst HCP-AQ-Mo-SO3H shows that the catalyst has a layered and interconnected structure; the central filamentous structure together constructs a 3D stacked spatial network structure, which exhibits certain slit-like mesoporous characteristics.

[0038] from Figure 2 As can be seen, the XPS spectrum shows two doublets, indicating that molybdenum exists in two oxidation states. The main peaks at 232.9 eV and 236.0 eV are attributed to Mo 3d, respectively. 5 / 2 and Mo 3d 3 / 2 , is Mo 6+ The characteristic signal was observed; simultaneously, another pair of main peaks were observed at 231.6 eV and 234.8 eV, indicating the presence of Mo in the material. 5+ .

[0039] from Figure 3 As can be seen from the XRD pattern analysis, the HCP-AQ, HCP-AQ-Mo, and HCP-AQ-Mo-SO3H spectra all exhibit broad peaks at approximately 16 and 22, which are typical characteristics of amorphous structures. The results indicate that the material maintains a highly disordered amorphous backbone from the initial polymer to the final modified catalyst. The introduction of molybdenum species and subsequent sulfonic acid group modification did not lead to significant crystallization. The three spectra are generally similar, with only minor differences in local intensity or broadening. This confirms that molybdenum and sulfonic acid groups are introduced in a highly dispersed state, without disrupting the amorphous network structure of the polymer, providing an important structural basis for its use as a homogeneous heterogeneous catalyst.

[0040] from Figure 4 It can be seen that the infrared spectrum at 878 cm⁻¹-1 The presence of characteristic absorption peaks at 1030 cm⁻¹, belonging to the Mo-O-Mo bond, directly confirms the successful incorporation of molybdenum into HCP-AQ-Mo and HCP-AQ-Mo-SO₃H materials. Furthermore, at 1030 cm⁻¹... -1 and 1170cm -1 The characteristic absorption peak observed at [location] is attributed to the asymmetric and symmetric stretching vibrations of the O=S=O bonds in the sulfonic acid group; while at 563 cm⁻¹... -1 The absorption peaks appearing at 1650 cm⁻¹ correspond to the stretching vibrations of the CS bonds connecting the sulfonic acid groups to the polymer backbone. These characteristic peaks indicate that the sulfonic acid groups have been covalently bonded to the polymer backbone. -1 1531 cm -1 and 1317 cm -1 The characteristic peak of amide appearing at approximately 3430 cm⁻¹ also indicates the successful introduction of 2-hydroxy-N-(quinoline-8-yl)benzamide; -1 The broad peaks at this point are attributed to overlapping O–H and N–H stretching vibrations. These features collectively indicate the successful formation of a sulfonated hypercrosslinked polymer backbone.

[0041] from Figure 5 It can be seen that the N2 adsorption-desorption test of HCP-AQ-Mo-SO3H shows that its isotherm morphology is complex: in the low pressure region (P / P0<0.1), it shows a type III curve with a small amount of adsorption, indicating that the interaction between the material surface and N2 molecules is weak; in the high pressure region (P / P0>0.4), the curve turns into a type II curve with obvious adsorption jump, and an H3 type hysteresis loop, which characterizes the typical pores of the sheet material, appears. These all point to the existence of a slit-like mesoporous structure in the material. Example 2

[0042] This application provides a method for preparing 2,5-furandicarboxaldehyde in a one-pot, one-step process from fructose, including the following steps: (1) 1.32 g of 2-hydroxy-N-(quinoline-8-yl)benzamide (5 mmol), 1.40 g of p-dichlorobenzyl (8 mmol), 3.24 g of anhydrous ferric chloride (20 mmol) and 40 mL of dichloroethane were added to a reaction flask and reacted at 90 °C for 20 h under a nitrogen atmosphere. After the reaction was completed, the solid was collected by filtration and washed with a large amount of methanol until the washing liquid was colorless. Then the solid was dried under vacuum at 80 °C to obtain the macromolecular ligand HCP-AQ; (2) Add 1.6 g of molybdenum acetylacetonate, 1.2 g of HCP-AQ obtained in the previous step and 50 mL of methanol to a reaction flask, and stir the mixture at 70 °C for 24 h. After the reaction is complete, filter and collect the solid, wash the solid three times with methanol, and dry the solid and label it as HCP-AQ-Mo; (3) Add 1.0 g of HCP-AQ-Mo, 5 mL of chlorosulfonic acid and 30 mL of dichloromethane obtained in the previous step to a reaction flask and stir at room temperature for 40 h. After the reaction is complete, slowly add the mixture to 300 mL of ice water. Filter to collect the solid, wash with water until the washing liquid is neutral, then wash with methanol three times, and dry the obtained solid under vacuum at 80 °C. This solid is designated as HCP-AQ-Mo-SO3H catalyst. (4) 180 mg fructose, 60 mg HCP-AQ-Mo-SO3H catalyst and 3 mL DMSO were added to a three-necked flask equipped with a magnetic stir bar and a thermometer, and the reaction was carried out at 140 °C for 10 h. After the reaction was completed, the yield of product DFF was 73% by gas chromatography with internal standard method. Example 3

[0043] This application provides a method for preparing 2,5-furandicarboxaldehyde in a one-pot, one-step process from fructose, including the following steps: (1) 1.32 g of 2-hydroxy-N-(quinoline-8-yl)benzamide (5 mmol), 1.05 g of p-dichlorobenzyl (6 mmol), 2.445 g of anhydrous ferric chloride (15 mmol) and 40 mL of dichloroethane were added to a reaction flask and reacted at 95 °C for 22 h under a nitrogen atmosphere. After the reaction was completed, the solid was collected by filtration and washed with a large amount of methanol until the washing liquid was colorless. Then the solid was dried under vacuum at 80 °C to obtain the macromolecular ligand HCP-AQ. (2) Add 1.6 g of molybdenum acetylacetonate, 1.0 g of HCP-AQ obtained in the previous step, and 50 mL of methanol to a reaction flask, and stir the mixture at 60 °C for 20 h. After the reaction is complete, filter and collect the solid, wash the solid three times with methanol, and dry the solid and label it as HCP-AQ-Mo; (3) Add 1.0 g of HCP-AQ-Mo, 5 mL of chlorosulfonic acid and 30 mL of dichloromethane obtained in the previous step to a reaction flask and stir at room temperature for 40 h. After the reaction is complete, slowly add the mixture to 300 mL of ice water. Filter to collect the solid, wash with water until the washing liquid is neutral, then wash with methanol three times, and dry the obtained solid under vacuum at 80 °C. This solid is designated as HCP-AQ-Mo-SO3H catalyst. (4) 180 mg fructose, 60 mg HCP-AQ-Mo-SO3H catalyst and 3 mL DMSO were added to a three-necked flask equipped with a magnetic stir bar and a thermometer, and the reaction was carried out at 140 °C for 10 h. After the reaction was completed, the yield of product DFF was 70% by gas chromatography with internal standard method. Example 4

[0044] This application provides a method for preparing 2,5-furandicarboxaldehyde in a one-pot, one-step process from fructose, including the following steps: (1) 1.32 g of 2-hydroxy-N-(quinoline-8-yl)benzamide (5 mmol), 1.05 g of p-dichlorobenzyl (6 mmol), 2.445 g of anhydrous ferric chloride (15 mmol) and 40 mL of dichloroethane were added to a reaction flask and reacted at 90 °C for 20 h under a nitrogen atmosphere. After the reaction was completed, the solid was collected by filtration and washed with a large amount of methanol until the washing liquid was colorless. Then the solid was dried under vacuum at 80 °C to obtain the macromolecular ligand HCP-AQ; (2) Add 2.4 g of molybdenum acetylacetonate, 1.2 g of HCP-AQ obtained in the previous step and 50 mL of methanol to a reaction flask, and stir the reaction at 75 °C for 26 h. After the reaction is complete, filter and collect the solid, wash the solid three times with methanol, and dry the solid and record it as HCP-AQ-Mo; (3) Add 1.0 g of HCP-AQ-Mo, 8 mL of chlorosulfonic acid and 30 mL of dichloromethane obtained in the previous step to a reaction flask and stir at room temperature for 30 h. After the reaction is complete, slowly add the mixture to 300 mL of ice water. Filter to collect the solid, wash with water until the washing liquid is neutral, then wash with methanol three times, and dry the obtained solid under vacuum at 80 °C, and record it as HCP-AQ-Mo-SO3H catalyst; (4) 180 mg fructose, 60 mg HCP-AQ-Mo-SO3H catalyst and 3 mL DMSO were added to a three-necked flask equipped with a magnetic stir bar and a thermometer, and the reaction was carried out at 140 °C for 10 h. After the reaction was completed, the yield of product DFF was 69% by gas chromatography with internal standard method. Example 5

[0045] This application provides a method for preparing 2,5-furandicarboxaldehyde in a one-pot, one-step process from fructose, including the following steps: (1) 1.32 g of 2-hydroxy-N-(quinoline-8-yl)benzamide (5 mmol), 1.05 g of p-dichlorobenzyl (6 mmol), 2.445 g of anhydrous ferric chloride (15 mmol) and 40 mL of dichloroethane were added to a reaction flask and reacted at 90 °C for 20 h under a nitrogen atmosphere. After the reaction was completed, the solid was collected by filtration and washed with a large amount of methanol until the washing liquid was colorless. Then the solid was dried under vacuum at 80 °C to obtain the macromolecular ligand HCP-AQ; (2) Add 1.6 g of molybdenum acetylacetonate, 1.2 g of HCP-AQ obtained in the previous step and 50 mL of methanol to a reaction flask, and stir the reaction at 70 °C for 24 h. After the reaction is completed, filter and collect the solid, wash the solid three times with methanol, and dry the solid and record it as HCP-AQ-Mo; (3) Add 1.0 g of HCP-AQ-Mo, 5 mL of chlorosulfonic acid and 30 mL of dichloromethane obtained in the previous step to a reaction flask and stir at room temperature for 40 h. After the reaction is complete, slowly add the mixture to 300 mL of ice water. Filter to collect the solid, wash with water until the washing liquid is neutral, then wash with methanol three times, and dry the obtained solid under vacuum at 80 °C. This solid is designated as HCP-AQ-Mo-SO3H catalyst. (4) 180 mg fructose, 30 mg HCP-AQ-Mo-SO3H catalyst and 2 mL DMSO were added to a three-necked flask equipped with a magnetic stir bar and a thermometer, and the reaction was carried out at 140 °C for 10 h. After the reaction was completed, the yield of product DFF was 68% by gas chromatography with internal standard method. Example 6

[0046] This application provides a method for preparing 2,5-furandicarboxaldehyde in a one-pot, one-step process from fructose, including the following steps: (1) In a 100 mL three-necked flask, 1.32 g (0.005 mol) of 2-hydroxy-N-(quinoline-8-yl)benzamide, 1.05 g (0.006 mol) of p-dibenzyl chloride, 2.445 g (0.015 mol) of anhydrous ferric chloride, and 40 mL of dichloroethane were added sequentially, and the mixture was reacted at 90 °C for 20 h under a N2 atmosphere. After the reaction was complete, the brown solid was collected by filtration and the precipitate was washed with a large amount of methanol until the filtrate was colorless. Finally, the solid was dried under vacuum at 80 °C. The solid was designated as HCP-AQ; (2) Add 1.6 g of molybdenum acetylacetonate, 1.2 g of HCP-AQ obtained in the previous step and 50 mL of methanol to a reaction flask, and stir the reaction at 70 °C for 24 h. After the reaction is completed, filter and collect the solid, wash the solid three times with methanol, and dry the solid and record it as HCP-AQ-Mo; (3) Add 1.0 g of HCP-AQ-Mo, 5 mL of chlorosulfonic acid and 30 mL of dichloromethane obtained in the previous step to a reaction flask and stir at room temperature for 40 h. After the reaction is complete, slowly add the mixture to 300 mL of ice water. Filter to collect the solid, wash with water until the washing liquid is neutral, then wash with methanol three times, and dry the obtained solid under vacuum at 80 °C, and record it as HCP-AQ-Mo-SO3H catalyst; (4) 180 mg fructose, 60 mg HCP-AQ-Mo-SO3H catalyst and 3 mL DMSO were added to a three-necked flask equipped with a magnetic stir bar and a thermometer, and the reaction was carried out at 120 °C for 12 h. After the reaction was completed, the yield of product DFF was 71% by gas chromatography with internal standard method.

[0047] Catalyst recovery example: The HCP-AQ-Mo-SO3H catalyst used in Example 1 was filtered, washed with methanol, and reused in the one-pot, one-step direct preparation of DFF from fructose, using the same method as in Example 1. The reaction was repeated five times, and the overall reaction results are shown in Table 1.

[0048] Table 1. Recycled catalyst HCP-AQ-Mo-SO3H used in the one-pot, one-step preparation of DFF from fructose.

[0049] As can be seen from Table 1, in the catalytic recovery example, the DFF gradually decreased from 75% in the first cycle to 64% in the fifth cycle. HCP-AQ-Mo-SO3H still maintained high catalytic activity after five catalytic cycles, proving that the catalyst HCP-AQ-Mo-SO3H prepared in this invention has catalytic stability and reusability.

[0050] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for preparing 2,5-furandicarboxaldehyde from fructose in a one-pot, one-step process, characterized in that, In an air atmosphere, using fructose as a raw material, HCP-AQ-Mo-SO3H catalyst is added, and the reaction is carried out in dimethyl sulfoxide under normal pressure to dehydrate and oxidize 2,5-furandicarboxaldehyde. The HCP-AQ-Mo-SO3H catalyst can be reused after filtration, separation, and washing.

2. The method according to claim 1, characterized in that: The HCP-AQ-Mo-SO3H catalyst was prepared by a method comprising the following steps: (1) 2-hydroxy-N-(quinoline-8-yl)benzamide, p-dichlorobenzyl and anhydrous ferric chloride were dispersed in a first organic solvent and heated in a nitrogen atmosphere. The solid and liquid were separated, the solid was washed and dried to obtain the macromolecular ligand HCP-AQ. (2) The molybdenum acetylacetonate and the macromolecular ligand HCP-AQ were heated and reacted in a second organic solvent. The solid and liquid were separated and the resulting solid was washed to obtain HCP-AQ-Mo. (3) Chlorosulfonic acid and HCP-AQ-Mo are stirred and reacted in a third organic solvent at room temperature. The reaction mixture is poured into ice water, filtered and the solid is collected. It is first washed with water until the washing liquid is neutral, then washed three times with methanol. After drying, it is named HCP-AQ-Mo-SO3H, which is the HCP-AQ-Mo-SO3H catalyst.

3. The method according to claim 2, characterized in that: In step (1), the molar ratio of benzamide to dibenzyl chloride and anhydrous ferric chloride is 1:(1-3):(2-5).

4. The method according to claim 2, characterized in that: In step (1), the first organic solvent is selected from toluene, methanol, ethyl acetate, ethanol, dichloromethane and dichloroethane; the heating temperature is 50-120℃ and the reaction time is 10-30h.

5. The method according to claim 2, characterized in that: In step (2), the mass ratio of the macromolecular ligand HCP-AQ to molybdenum acetylacetonate is 1:(1-3).

6. The method according to claim 2, characterized in that: In step (2), the second organic solvent is selected from toluene, methanol, ethyl acetate, ethanol and dichloromethane; the heating temperature is 50-100℃ and the reaction time is 12-48h.

7. The method according to claim 2, characterized in that: In step (3), the mass ratio of HCP-AQ-Mo to chlorosulfonic acid is 1:(2-17); the third organic solvent is selected from toluene, methanol, ethyl acetate, ethanol and dichloromethane; the reaction time is 10-70 h.

8. The method according to claim 1, characterized in that: The mass ratio of the HCP-AQ-Mo-SO3H catalyst to fructose is 1:(2-6).

9. The method according to claim 1, characterized in that: The mass ratio of dimethyl sulfoxide to fructose is (10-25):

1.

10. The method according to claim 1, characterized in that: The heating reaction temperature is 120–160℃, and the reaction time is 3–15 h.

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