Method for preparing 2, 5-furandicarboxylic acid

Abstract

The invention relates to the technical field of chemical synthesis, and discloses a method for preparing 2, 5-furandicarboxylic acid, which comprises the following steps: dispersing cobalt nitrate and nickel sulfate into an aqueous solution of polyvinylpyrrolidone at room temperature; adding a sodium borohydride solution to obtain nano colloid; preparing an aqueous suspension of cerium oxide, and adding the aqueous suspension into the nano colloid; centrifugally filtering, and recovering a solid product; washing the solid product; centrifuging, putting solid powder obtained after centrifuging into a drying oven, and drying; and calcining and grinding the solid powder to finally prepare the Co-Ni / CeO2 catalyst. And dissolving 5-hydroxymethylfurfural in water at normal temperature, adding the prepared Co-Ni / CeO2 catalyst and a sodium hypochlorite solution, reacting, and filtering to remove the catalyst, thereby obtaining the 2, 5-furandicarboxylic acid. The method disclosed by the invention has the advantages of no use of strong base, low reaction temperature, short reaction time, few byproducts, greenness and sustainability.

Description

Technical Field

[0001] This invention relates to the field of chemical synthesis technology, and in particular to a method for preparing 2,5-furandicarboxylic acid. Background Technology

[0002] 2,5-Furfurandicarboxylic acid (FDCA) is a white solid powder under normal conditions. It has low water solubility because it is a dicarboxylic acid containing two carboxyl groups. It is more soluble in alkaline solutions but insoluble in strongly acidic solutions, and its chemical properties are relatively stable. FDCA is one of the 13 key bio-based platform compounds being promoted, and it is the only aromatic ring monomer among them with a "rigid" structure. It can replace the benzene ring series in the eight basic petroleum-based platform compounds (triphenyltriene-yne-naphthalene) to synthesize novel biomass-based polyester materials (PEF) with excellent performance. FDCA can also be used to synthesize various important chemical, material, and pharmaceutical intermediates such as 2,5-bis(aminomethyl)tetrahydrofuran and adipic acid through hydrogenation, acylation, and ring-opening reactions. FDCA has a wide range of applications, and in-depth research on its preparation has become an important research topic in the conversion of biomass resources.

[0003] .

[0004] FDCA can be prepared from biomass derivatives such as 5-hydroxymethylfurfural (HMF), furfural, furan, diethylene glycol, and disaccharic acid, among which the oxidation of the biomass platform compound HMF to FDCA is the most promising method. Compared with other methods, this synthetic route is more direct and simpler, and the synthesis efficiency of FDCA is higher.

[0005] Because alkaline substances such as sodium hydroxide, sodium carbonate, and potassium carbonate can promote the hydration steps between water and HMF molecules, thereby reducing the barrier to the conversion of HMF to FDCA, early studies on the oxidation of HMF to prepare FDCA were mostly carried out in alkaline solution systems. However, the large-scale use of homogeneous strong bases not only corrodes equipment, but also requires the neutralization of excess free base with acid during the later product separation, leading to potential environmental pollution and making it difficult to meet the needs of future large-scale industrial production. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a method for preparing 2,5-furandicarboxylic acid, achieving the goals of low reaction temperature, short reaction time, and few byproducts.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows: A method for preparing 2,5-furandicarboxylic acid includes the following steps: (1) Preparation of Co-Ni / CeO2 catalyst: At room temperature, the precursors cobalt nitrate and nickel sulfate were dispersed in an aqueous solution of polyvinylpyrrolidone; the mixture was stirred thoroughly; then, sodium borohydride solution was added dropwise to the well-stirred solution to obtain nanocolloids; next, an aqueous suspension of cerium oxide was prepared and added to the nanocolloids; under room temperature conditions, the mixture was continuously stirred, centrifuged, and filtered to recover the solid product. The recovered solid product was first washed with hot deionized water to remove polyvinylpyrrolidone; subsequently, it was washed further with excess deionized water to remove sodium from the solid. + and Cl - After washing, the solid is centrifuged, and the resulting solid powder is placed in an oven to dry. After drying, the solid powder is calcined. After calcination, the product is ground to finally obtain the Co-Ni / CeO2 catalyst. (2) Preparation of 2,5-furandicarboxylic acid: At room temperature, 5-hydroxymethylfurfural is dissolved in water, and the prepared Co-Ni / CeO2 catalyst and sodium hypochlorite solution are added. After the reaction, the catalyst is removed by filtration to obtain 2,5-furandicarboxylic acid.

[0008] In the above scheme, in step (1), the molar ratio of cobalt nitrate and nickel sulfate is 3:7.

[0009] In the above scheme, in step (1), the mass ratio of polyvinylpyrrolidone to the sum of cobalt nitrate and nickel sulfate in the polyvinylpyrrolidone aqueous solution is 1.2:1.

[0010] In the above scheme, in step (1), the molar ratio of sodium borohydride to the sum of cobalt nitrate and nickel sulfate is 5:1.

[0011] In the above scheme, in step (1), the oven temperature is 60℃ and the drying time is 12h.

[0012] In the above scheme, in step (1), the temperature of the hot deionized water is 90-100℃.

[0013] In the above scheme, in step (2), the mass ratio of Co-Ni / CeO2 catalyst to 5-hydroxymethylfurfural is 2.5:1.

[0014] In the above scheme, in step (2), the reaction temperature is 30-40℃ and the reaction time is 2 h.

[0015] In the above scheme, in step (2), the mass-to-volume ratio of 5-hydroxymethylfurfural to sodium hypochlorite solution is 1:(6.5-9).

[0016] In the above scheme, in step (2), the sodium hypochlorite solution is a sodium hypochlorite solution with an effective chlorine content of 4.5~5%.

[0017] The method for preparing 2,5-furandicarboxylic acid provided by the present invention, through the above technical solution, has the following beneficial effects: 1. The preparation process of this invention uses sodium hypochlorite solution, which can realize the direct and efficient generation of FDCA from HMF, with short reaction time and easy-to-achieve reaction conditions.

[0018] 2. The FDCA prepared by this invention has few impurities, requires no purification treatment, and the yield can reach over 93%.

[0019] 3. The method of the present invention does not use strong alkali, is green, environmentally friendly, low in energy consumption, simple in steps, and low in production cost, making it very suitable for industrial production. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0021] Figure 1 The image shows the in-situ infrared spectrum of furfural oxidation on the Co-Ni / CeO2 catalyst prepared in Example 1 of this invention.

[0022] Figure 2 The XRD patterns are of the Co-Ni / CeO2, Co / CeO2, Ni / CeO2, CeO2(0) and CeO2 catalysts prepared in Example 1 of this invention.

[0023] Figure 3 This is a high-performance liquid chromatogram of 2,5-furandicarboxylic acid prepared in Example 1 of the present invention. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0025] This invention provides a method for preparing 2,5-furandicarboxylic acid, and specific embodiments are as follows: Example 1 (1) Preparation of Co-Ni / CeO2 catalyst: At room temperature, cobalt nitrate [Co(NO3)2] and nickel sulfate (NiSO4) precursors in a molar ratio of 3:7 were weighed and dispersed in an aqueous solution of polyvinylpyrrolidone (PVP). The mass ratio of the sum of Co(NO3)2 and NiSO4 was controlled at 1.2:1. The mixture was thoroughly stirred to ensure uniform dispersion. Subsequently, sodium borohydride (NaBH4) solution was added dropwise to the well-stirred solution, with a molar ratio of sodium borohydride to the sum of Co(NO3)2 and NiSO4 set at 5:1. After the addition was complete, a nanocolloid was obtained. Next, an aqueous suspension of cerium oxide (CeO2) was prepared and added to the nanocolloid. The mixture was stirred continuously for 12 h at room temperature, followed by centrifugation and filtration to recover the solid product.

[0026] The recovered solids were first washed with deionized water at 95°C to remove polyvinylpyrrolidone. Subsequently, they were washed further with excess deionized water to remove sodium from the solids. + and Cl - .

[0027] After washing, the solid was centrifuged. The resulting solid powder was placed in a 60℃ oven and dried using a forced-air drying method. After drying, the solid powder was calcined at 330℃ for 4 hours. After calcination, the product was ground to obtain the final Co-Ni / CeO2 catalyst. The in-situ infrared spectrum is shown below. Figure 1 As shown.

[0028] Reference catalyst: CeO2(0): Prepared by the same method in the absence of Co(NO3)2 and NiSO4; Co / CeO2: The precursor was prepared using the same method with only Co(NO3)2 added; Ni / CeO2: The precursor was prepared using the same method with only NiSO4 added.

[0029] from Figure 1 As can be seen, the dynamic adsorption behavior of the oxidation process on the surface of Co(NO3)2 catalyst was studied using in-situ Fourier transform infrared spectroscopy (FTIR). 2143 cm⁻¹ -1 The transient signal at [location] is attributed to physically adsorbed linear CO species, and its intensity decays rapidly in the initial stage of helium purging (1-10 min), confirming the desorption process of weakly interacting adsorbates. Meanwhile, at 2000-2100 cm⁻¹... -1The characteristic peaks within this range exhibit a slow intensity decay trend, which is speculated to be CO adsorbed by monodentate coordination on the surface of the metal active centers (Co, Ni). This phenomenon indicates the presence of moderately strong chemisorption sites on the catalyst surface (consistent with the conclusion on chemisorption). When the purge time is extended to 20-60 min, the absorption peaks in this region tend to stabilize, combined with the 2150-2200 cm⁻¹ range. -1 The absence of a significant signal within this range suggests that residual CO molecules may be anchored to oxygen vacancy sites on the bimetallic alloy or CeO2 support via strong electron interactions. This is particularly evident in the 2200-2400 cm⁻¹ range. -1 The broadened absorption bands appear within the range, with the signal near 2350 cm⁻¹ attributable to Ce. 3+ -O-CO - The formation of carbonate-like species directly confirms the activation of CO molecules by the CeO2 support through oxygen vacancies. The in-situ analysis results indicate that a synergistic adsorption system exists on the surface of the Co-Ni / CeO2 catalyst, consisting of both active metal sites and support defect sites. The metal sites dominate the chemisorption and activation of CO, while the CeO2 oxygen vacancies participate in the stabilization of reaction intermediates by forming surface carbonate species. This bifunctional adsorption characteristic provides important evidence for the mechanism of action of active sites in the HMF oxidation reaction.

[0030] The XRD patterns of the prepared catalysts are as follows: Figure 2 As shown. From Figure 2 The X-ray diffraction (XRD) analysis results of CeO2 reference material and its metal-doped modified catalysts can be seen. By comparing and analyzing the diffraction patterns of Co-Ni / CeO2, Co / CeO2, Ni / CeO2 and modified CeO2(0), it was found that all samples exhibited typical diffraction peaks of cubic fluorite structure at characteristic angles such as 2θ = 33.2°, 38.6°, 55.7° and 66.4° (PDF#81-0792), indicating that metal doping treatment did not lead to a significant change in the crystal phase structure of the support. It should be noted that although no characteristic diffraction peaks of metal oxides were detected in each modified catalyst (possibly due to the metal loading being below the detection limit of the XRD instrument), the intensity of its main diffraction peaks showed a systematic attenuation compared with the undoped CeO2 support. This phenomenon can be attributed to the lattice distortion effect caused by electron transfer between transition metal species and the CeO2 lattice, and at the same time provides evidence that transition metal ions were successfully immobilized on the support surface through the doping process. The results of this study demonstrate that the proposed catalyst system construction strategy can effectively maintain the integrity of the support structure while achieving controllable loading of the active components.

[0031] (2) Preparation of 2,5-furandicarboxylic acid The oxidation reaction of HMF was carried out in a 100 mL standard side-armed test tube reactor. The specific operation procedure is as follows: First, 0.5 mmol of HMF raw material was accurately weighed and placed in the reaction vessel, followed by the addition of a certain amount of Co-Ni / CeO2 multimetallic composite catalyst. Then, a sodium hypochlorite solution (antifomin, analytical grade) containing 4.5%-5.0% (w / w) of available chlorine was quantitatively transferred as the oxidation medium. The reaction system was fixed in a constant-temperature magnetic stirrer. After the temperature reached the set value, a mechanical stirrer was started under an air pressure of 0.1 MPa, maintaining a constant speed and a predetermined reaction time to complete the catalytic oxidation reaction. After the reaction, the catalyst was removed by filtration, and the FDCA yield was determined to be 93.8% by high-performance liquid chromatography.

[0032] The reaction formula is as follows:

[0033] Depend on Figure 3 The high-performance liquid chromatogram shows that 2,5-furandicarboxylic acid is present at wavelengths of 240 nm-280 nm and retention times of 1.98 min-2.00 min, with a distinct product peak and fewer impurity peaks.

[0034] Comparative Example 1 The difference between this embodiment and Example 1 is that the Co-Ni / CeO2 multimetallic composite catalyst was replaced with the control catalyst CeO2(0), and the calcination temperature was 330℃. All other aspects were the same as in Example 1. The FDCA yield was determined to be 49.0% by high-performance liquid chromatography.

[0035] Comparative Example 2 The difference between this embodiment and Example 1 is that the Co-Ni / CeO2 multimetallic composite catalyst was replaced with the control catalyst Co / CeO2, and the calcination temperature was 330℃. Otherwise, the process was the same as in Example 1. The FDCA yield was determined to be 61.7% by high-performance liquid chromatography.

[0036] Comparative Example 3 The difference between this embodiment and Example 1 is that the Co-Ni / CeO2 multimetallic composite catalyst was replaced with the control catalyst Ni / CeO2, and the calcination temperature was 330℃. All other aspects are the same as in Example 1. The FDCA yield was determined to be 0.12% by high-performance liquid chromatography.

[0037] Comparative Example 4 The difference between this comparative example and Example 1 is that NiSO4 was replaced with niobium oxalate; otherwise, the results are the same as in Example 1. The FDCA yield was determined to be 55.5% by high-performance liquid chromatography.

[0038] Comparative Example 5 The difference between this comparative example and Example 1 is that in step (2), the sodium hypochlorite solution (Anti-Fumin) with an effective chlorine mass fraction of 5% was replaced with the same volume of water, while the rest was the same as in Example 1. After the reaction was completed, the catalyst was removed by filtration, and the FDCA yield was determined to be 7.3% by high performance liquid chromatography.

[0039] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing 2,5-furandicarboxylic acid, characterized in that, Includes the following steps: (1) Preparation of Co-Ni / CeO2 catalyst: At room temperature, the precursors cobalt nitrate and nickel sulfate were dispersed in an aqueous solution of polyvinylpyrrolidone. The mixed solution was stirred thoroughly; then, sodium borohydride solution was added dropwise to the well-stirred solution to obtain nanocolloids; next, an aqueous suspension of cerium oxide was prepared and added to the nanocolloids; under room temperature conditions, the mixture was continuously stirred, centrifuged, and filtered to recover the solid product. The recovered solid product was first washed with hot deionized water to remove polyvinylpyrrolidone; subsequently, it was washed further with excess deionized water to remove sodium from the solid. + and Cl - After washing, the solid is centrifuged, and the resulting solid powder is placed in an oven to dry. After drying, the solid powder is calcined. After calcination, the product is ground to finally obtain the Co-Ni / CeO2 catalyst. (2) Preparation of 2,5-furandicarboxylic acid: At room temperature, 5-hydroxymethylfurfural is dissolved in water, and the prepared Co-Ni / CeO2 catalyst and sodium hypochlorite solution are added. After the reaction, the catalyst is removed by filtration to obtain 2,5-furandicarboxylic acid.

2. The method for preparing 2,5-furandicarboxylic acid according to claim 1, characterized in that, In step (1), the molar ratio of cobalt nitrate to nickel sulfate is 3:

7.

3. The method for preparing 2,5-furandicarboxylic acid according to claim 1, characterized in that, In step (1), the mass ratio of polyvinylpyrrolidone to the sum of cobalt nitrate and nickel sulfate in the aqueous solution of polyvinylpyrrolidone is 1.2:

1.

4. The method for preparing 2,5-furandicarboxylic acid according to claim 1, characterized in that, In step (1), the molar ratio of sodium borohydride to the sum of cobalt nitrate and nickel sulfate is 5:

1.

5. The method for preparing 2,5-furandicarboxylic acid according to claim 1, characterized in that, In step (1), the oven temperature is 60℃ and the drying time is 12h.

6. The method for preparing 2,5-furandicarboxylic acid according to claim 1, characterized in that, In step (1), the temperature of the hot deionized water is 90-100℃.

7. The method for preparing 2,5-furandicarboxylic acid according to claim 1, characterized in that, In step (2), the mass ratio of Co-Ni / CeO2 catalyst to 5-hydroxymethylfurfural is 2.5:

1.

8. The method for preparing 2,5-furandicarboxylic acid according to claim 1, characterized in that, In step (2), the reaction temperature is 30-40℃ and the reaction time is 2 h.

9. The method for preparing 2,5-furandicarboxylic acid according to claim 1, characterized in that, In step (2), the mass-to-volume ratio of 5-hydroxymethylfurfural to sodium hypochlorite solution is 1:(6.5-9).

10. A method for preparing 2,5-furandicarboxylic acid according to claim 1, characterized in that, In step (2), the sodium hypochlorite solution is a sodium hypochlorite solution with an effective chlorine content of 4.5~5%.

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