A catalyst for the production of 2,5-furandicarboxaldehyde from glucose and its preparation method

Abstract

This invention discloses a catalyst for the production of 2,5-furandicarboxaldehyde from glucose and its preparation method. The catalyst uses ZSM-5 molecular sieve as a support, and through loading active components Nb and Ni, a multi-active-center system with a highly efficient synergistic effect is constructed via a staged heat treatment process involving oxidative calcination at 500 °C and hydrogen reduction at 400 °C. This invention utilizes the kinetic matching between the Nb and Ni components and the acid sites of the support to achieve an integrated and highly efficient conversion of glucose to DFF in DMF solvent, with a raw material conversion rate reaching up to 99%. Through the spatial synergy of the bimetallic active sites, the reaction intermediate 5-HMF can be produced and used immediately, effectively inhibiting coking and the formation of humic acid. This catalyst is not dependent on precious metals and possesses characteristics such as high activity, good stability, and excellent carbon balance, giving it a significant competitive advantage in the field of high-value utilization of biomass.

Description

Technical Field

[0001] This invention relates to the fields of biomass resource utilization and heterogeneous catalysis technology, specifically to a catalyst for the production of 2,5-furandicarboxaldehyde (DFF) from glucose and its preparation method. Background Technology

[0002] With the increasing depletion of petrochemical resources and the growing severity of environmental problems, the production of high-value-added chemicals from renewable biomass resources has become a research hotspot in the field of sustainable development. Among numerous biomass platform compounds, DFF, due to its symmetrical aldehyde and furan rings in its molecular structure, is widely used in the synthesis of pharmaceutical intermediates, novel self-healing resins, high-performance polymers (such as polyesters and polyamides), and fuel additives.

[0003] The preparation of DFF from readily available and inexpensive glucose typically involves a cascade reaction pathway: glucose-fructose-5-hydroxymethylfurfural (HMF)-DFF. This pathway involves three core steps: glucose isomerization (L-acid catalysis), fructose dehydration (B-acid catalysis), and selective oxidation of HMF (oxidation site catalysis). However, existing technologies face the following significant challenges in achieving this integrated conversion:

[0004] First, intermediate stability and side reaction control: The intermediate 5-HMF has extremely high chemical reactivity and readily undergoes self-polymerization in acidic reaction systems, or condenses with unreacted monosaccharides to generate dark black, insoluble polymeric byproducts—humins. The formation of humins not only severely reduces the carbon balance and DFF selectivity of the reaction, but also coats the surface of the catalyst's active sites, leading to rapid catalyst deactivation due to carbon buildup.

[0005] Secondly, multi-site catalytic mismatch: Traditional integrated catalytic systems often struggle to balance the rates of isomerization, dehydration, and oxidation. Insufficient activity at oxidation sites can lead to a large accumulation of 5-HMF within the pores, thereby inducing the aforementioned coking side reactions.

[0006] Finally, there is the issue of dependence on precious metals and cost: most catalysts currently capable of achieving efficient HMF oxidation rely on precious metals such as Ru, Pd, and Pt. Precious metal catalysts are not only expensive, but also susceptible to poisoning by oxygen-containing functional groups in complex biomass reaction systems, resulting in poor stability for repeated use.

[0007] Therefore, developing a low-cost, non-precious metal multifunctional composite catalyst that precisely controls the distribution of Lewis acid (L acid) and Brønsted acid (B acid) and combines it with efficient redox sites to achieve the "on-demand" synergistic conversion of intermediate 5-HMF is of great practical significance for inhibiting humin formation, improving DFF selectivity, and promoting the industrial utilization of biomass resources. Summary of the Invention

[0008] The purpose of this invention is to provide a catalyst for the production of 2,5-furandicarboxaldehyde from glucose and its preparation method, which solves the problems of catalyst deactivation caused by the generation of a large amount of byproduct humic acid in existing catalytic processes and the poor stability of catalysts when reused.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] A method for preparing a catalyst for the production of 2,5-furandicarboxaldehyde from glucose specifically includes the following steps:

[0011] S1: Impregnation: The precursor solution of Nb and the precursor solution of Ni are mixed with ZSM-5 after high-temperature calcination in a muffle furnace using a co-impregnation method, and stirred at 40~80 ℃.

[0012] S2: Oxidative roasting: After drying the material at 70~100 ℃, it is roasted at a constant temperature of 300~500 ℃ in an air atmosphere in a muffle furnace;

[0013] S3: Reduction treatment: The roasted material is heated to 200~400 ℃ in a tube furnace under a reducing atmosphere of H2 for constant temperature reduction.

[0014] In step S1, the precursor of Nb is ammonium niobate oxalate hydrate, and the precursor of Ni is nickel nitrate hexahydrate.

[0015] The loading of Nb in the catalyst is 1-5 wt%, and the loading of Ni in the catalyst is 1-5 wt%.

[0016] The catalyst has a specific surface area of ​​257.48-304.67 m². 2 / g, with an average pore size of 2.39-2.87 nm and a pore volume of 0.15-0.22 cm³. 3 / g.

[0017] The preferred calcination temperature in the muffle furnace during step S2 is 500 °C.

[0018] The preferred calcination temperature for the tubular furnace in step S3 is 400 ℃.

[0019] The specific method for preparing 2,5-furandicarboxaldehyde from glucose is as follows: by weight, 0.10~0.20 parts of glucose, 0.01~0.03 parts of Nb-Ni@ZSM-5 catalyst and 15-20 parts of organic solvent are mixed, heated to 100~180 ℃ in a closed environment under air atmosphere, and refluxed to carry out the catalytic reaction.

[0020] Preferably, the organic solvent is one or more of DMF, DMSO, and GVL, and more preferably, the organic solvent is DMF.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] High conversion rate and selectivity: The glucose conversion rate reaches over 99%, and the DFF selectivity is significantly better than that of conventional acid catalysts.

[0023] Good cycle stability: The catalyst can be easily recovered by centrifugation. The activity is stable in the first 3 cycles and only slightly decreases in the 5th cycle, showing excellent potential for industrial application.

[0024] Low cost: It successfully avoids the use of precious metals and achieves efficient integrated conversion by using equivalent non-precious metals. Attached Figure Description

[0025] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without any creative effort.

[0026] Figure 1 This invention relates to the N2 adsorption-desorption curves and pore size distribution of the Nb-Ni@ZSM-5 catalyst.

[0027] Figure 2 This is a TEM image of the 2%Nb-5%@ZSM-5 catalyst of the present invention.

[0028] Figure 3 This is the XRD pattern of the Nb-Ni@ZSM-5 catalyst of the present invention.

[0029] Figure 4 This is an XPS plot of the 2%Nb-5%@ZSM-5 catalyst of the present invention.

[0030] Figure 5 This is the Py-IR spectrum of the 2%Nb-5%@ZSM-5 catalyst of the present invention.

[0031] Figure 6 This is a schematic diagram of the structure of Nb-Ni@ZSM-5 according to the present invention. Detailed Implementation

[0032] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0033] A method for preparing a catalyst for the production of 2,5-furandicarboxaldehyde from glucose specifically includes the following steps:

[0034] S1: Impregnation: The precursor solution of Nb and the precursor solution of Ni are mixed with ZSM-5 calcined at high temperature in a muffle furnace using a co-impregnation method, and stirred at 40~80 ℃ for 12~24 h.

[0035] S2: Oxidative roasting: After drying the material at 70~100 ℃, the temperature is programmed to rise to 300~500 ℃ in an air atmosphere in a muffle furnace and roasted at a constant temperature for 3~5 h;

[0036] S3: Reduction treatment: The calcined material is heated to 200~400 ℃ in a tube furnace under a reducing atmosphere of H2 and reduced at a constant temperature for 2~4 h.

[0037] In one or more embodiments, the precursor of Nb in step S1 is ammonium niobate oxalate hydrate, and the precursor of Ni is nickel nitrate hexahydrate.

[0038] In one or more embodiments, the catalyst has a specific surface area of ​​257.48-304.67 m². 2 / g, with an average pore size of 2.39-2.87 nm and a pore volume of 0.15-0.22 cm³. 3 / g.

[0039] In step S1 of this invention, the precursors of Nb and Ni are loaded onto the surface of ZSM-5 using an impregnation method. Then, in step S2, air calcination is performed to allow Nb to be highly dispersed as NbO. x The species form is anchored on the carrier surface (forming an Nb–O–Si / Nb–O–Al structure), allowing Ni to exist in a metallic state. 0 With Ni in oxidized state 2+ The coexisting forms are highly dispersed on the carrier surface and in the pores, among which Ni 2+ Stable anchoring is achieved by forming a Ni-O-Si / Ni-O-Al structure, and it is combined with the in-situ formed Ni 0 Nanoclusters construct a metal-oxide interface with highly redox activity. The final step, S3, reduces the Ni oxide to elemental Ni. Nb in the catalyst exists in a high valence state (Nb...). 5+The presence of Nb species on the surface, exhibiting a coordinated unsaturated state and strong electron pair acceptance, allows for the formation of effective Lewis acid sites on the support surface. These sites are specifically responsible for isomerizing glucose into fructose. The existing Brønsted acid sites on ZSM-5 then dehydrate the generated fructose, converting it into the intermediate 5-HMF. Reduced Ni not only assists in the initial activation of glucose molecules but, more importantly, reacts rapidly with the 5-HMF generated from the acid sites in an air atmosphere, undergoing a selective oxidation reaction to generate DFF. This invention, through the introduction of Nb and Ni bimetals and the porous structure of ZSM-5, constructs a highly efficient cascade catalytic cycle, effectively solving the problem of intermediate coking (humin) caused by slow reaction steps in traditional catalysts, thus achieving a glucose conversion rate of up to 99%.

[0040] In one or more embodiments, the Nb loading in the catalyst is 1-5 wt%, for example, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, or any two of the above values.

[0041] In one or more embodiments, the Ni loading in the catalyst is 1-5 wt%, for example, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, or any two of the above values. The Nb or Ni loading refers to the mass of the corresponding substance in ZSM-5.

[0042] In one or more embodiments, the muffle furnace calcination temperature in step S2 is preferably 500 °C, for example, 300 °C, 325 °C, 350 °C, 375 °C, 400 °C, 425 °C, 450 °C, 475 °C, 500 °C, or any two of the above values.

[0043] In one or more embodiments, the calcination temperature of the tubular furnace in step S3 is preferably 400 °C, for example, 200 °C, 225 °C, 250 °C, 275 °C, 300 °C, 325 °C, 350 °C, 375 °C, 400 °C, or any two of the above values.

[0044] The specific method for preparing 2,5-furandicarboxaldehyde from glucose is as follows: by weight, 0.10~0.20 parts of glucose, 0.01~0.03 parts of Nb-Ni@ZSM-5 catalyst and 15-20 parts of organic solvent are mixed, heated to 100~180 ℃ in a closed environment under air atmosphere, and refluxed to carry out the catalytic reaction.

[0045] In one or more embodiments, the reaction temperature for the conversion of glucose to DFF is preferably 180 °C, for example, 100 °C, 110 °C, 120 °C, 130 °C, 140 °C, 150 °C, 160 °C, 170 °C, 180 °C, or any two of the above values.

[0046] In one or more embodiments, the catalytic reaction time is 1 to 12 hours, preferably 6 hours, for example 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, or 12 hours.

[0047] Preferably, the organic solvent is one or more of DMF, DMSO, and GVL. More preferably, the organic solvent is DMF, whose strong polarity can effectively stabilize the transition state during the isomerization process and promote the mass transfer and activation of air oxygen on the catalyst surface.

[0048] Example 1:

[0049] A method for preparing a catalyst for the production of 2,5-furandicarboxaldehyde from glucose specifically includes the following steps:

[0050] S1: Impregnation: The co-impregnation method is adopted, and the ammonium oxalate solution of niobate, nickel nitrate solution and ZSM-5 calcined at high temperature in muffle furnace are mixed and stirred at 80 ℃ for 12 h;

[0051] S2: Oxidative roasting: After drying the material at 105 °C, it is heated to 500 °C in an air atmosphere in a muffle furnace and roasted at a constant temperature for 4 h.

[0052] S3: Reduction treatment: The calcined material was heated to 400 ℃ in a tube furnace under a reducing atmosphere of H2 and reduced at a constant temperature for 2 h to obtain 2%Nb-5%Ni@ZSM-5 catalyst.

[0053] Examples 2-5

[0054] Except for the loading of Nb and Ni, the conditions in Examples 2-5 are the same as those in Example 1, as detailed in Table 1.

[0055] Comparative Example 1

[0056] The difference between this comparative example and Example 1 is that no ammonium niobate oxalate solution was added to the raw materials and the Nb loading was 5%, resulting in a 5% Nb@ZSM-5 catalyst.

[0057] Comparative Example 2

[0058] The difference between this comparative example and Example 1 is that nickel nitrate solution was not added to the raw materials, and 5%Ni@ZSM-5 was finally obtained.

[0059] Comparative Example 3

[0060] The difference between this comparative example and Example 1 is that step S3 was not performed. A large accumulation of 5-HMF was detected during the reaction (instantaneous yield exceeding 15%), the final DFF yield was only 31%, and the reaction solution was dark in color due to intermediate polymerization.

[0061] The catalysts prepared in the above examples were subjected to BET tests, and the results are shown in Table 1. The 2%Nb-5%Ni@ZSM-5 catalyst prepared in Example 1 had a specific surface area of ​​273.34 m². 2 / g, the pore distribution shows that micropores and mesopores coexist, confirming that the molecular sieve structure is intact and has excellent mass transfer channels after continuous heat treatment.

[0062] Table 1

[0063]

[0064] Figure 2 and 3 The XRD and TEM results of the prepared catalyst show that the catalyst maintains the typical MFI topology, with no metal segregation peaks, and the molecular sieve structure remains intact; the reduced Ni nanoclusters are uniformly distributed in size between 2-5 nm, exhibiting atomic-level high dispersion.

[0065] Figure 4 and 5 XPS and Py-IR analyses of the prepared catalyst showed that the active components Nb and Ni were highly dispersed on the ZSM-5 surface, significantly increasing the Lewis acid content of the system. This specific L / B acid ratio (1:1.14) ensured a perfect match between the isomerization and dehydration rates, providing ample precursors for the subsequent Ni-catalyzed 5-HMF oxidation. Figure 4 As shown in (a), in the 2%Nb-5%Ni@ZSM-5 bimetallic catalyst sample, Nb 3d 5 / 2 The binding energy is 207.48 eV, indicating that Nb is in the form of Nb. 5+ The oxidized state remains stable and has not been reduced to a lower oxidation state by hydrogen. For example... Figure 4 As shown in (b), a distinct Ni appears at 853.13 eV. 0 Characteristic peaks, and Ni at 855.95 eV. 2+ The main peak and the satellite peak at 861.66 eV are also clearly visible. The high binding energy sides of 873.63 eV and 879.92 eV correspond to Ni, respectively. 2+ with Ni 0 Ni 2p 1 / 2 Spin-orbit splitting peak.

[0066] Characterization results show that the active components Nb and Ni were successfully supported on the ZSM-5 molecular sieve support, and the preparation process did not damage the framework structure of the support. The active components were uniformly dispersed on the support surface, and the total acid content of the catalyst reached 0.85-1.2 mmol / g (the content of Li and B acids was quantitatively estimated by pyridine adsorption infrared spectroscopy, and the total acid content was obtained by summing the two). The specific surface area of ​​the prepared catalyst reached 273.34 m² / g, and the pore size distribution was relatively uniform. The average pore size of the catalyst was about 2.68 nm, which is beneficial to the diffusion and mass transfer of molecular substrates.

[0067] Application examples

[0068] The method for preparing DFF from glucose is as follows:

[0069] S1: By weight, 0.10 g of glucose, 15 mL of organic solvent and 0.03 g of the catalyst prepared in the examples and comparative examples were placed in a round-bottom flask. The rotor speed was set to 600 r / min, a condenser was connected, and reflux was performed. The catalytic reaction temperature was 180 °C. After isomerization and oxidation reactions, glucose was converted into DFF.

[0070] S2: The mixture obtained in step S1 was filtered, the solid Nb-Ni@ZSM-5 catalyst was recovered, the liquid product was diluted in a certain proportion and then detected by liquid chromatography. The glucose conversion rate, DFF yield and 5-HMF content were calculated, as shown in Table 2.

[0071] In the embodiments of the present invention, the conversion rate and selectivity were calculated using the external standard method of liquid chromatography, with 2,5-furandicarboxaldehyde standard selected as the external standard, and the standard curve was determined. The calculation formula is as follows:

[0072]

[0073]

[0074] Table 2

[0075]

[0076] The results above, along with real-time HPLC monitoring showing that the highest instantaneous yield of 5-HMF using the Nb-Ni@ZSM-5 catalyst was only 4.1%, indicate that the Nb-Ni@ZSM-5 catalyst solves the problem of intermediate coking (humin) caused by the slow reaction in a certain step of traditional catalysts, thus achieving a maximum glucose conversion rate of 99%. The 2%Nb-5%Ni@ZSM-5 catalyst showed the best catalytic effect. The 2%Nb-5%Ni@ZSM-5 catalyst will be recycled for reuse. This will be done in steps S3-S4.

[0077] S3: The 2%Nb-5%Ni@ZSM-5 catalyst recovered in step S2 is washed with anhydrous ethanol at least 5 times, and then dried in an oven at 80~100℃ overnight to obtain the 2%Nb-5%Ni@ZSM-5 catalyst after one recycling.

[0078] S4: The 2%Nb-5%Ni@ZSM-5 catalyst obtained in step S3 was used again as a catalyst for the glucose-to-DFF conversion reaction. The reaction steps were the same as in S1, S2, and S3, resulting in a 2%Nb-5%Ni@ZSM-5 catalyst that could be recycled twice. This cycle was repeated 5 times. The glucose conversion rate and DFF yield were calculated during the process. The results are shown in Table 3.

[0079] Table 3

[0080]

[0081] As can be seen from the data in Table 3, the composite acid catalyst prepared in this invention exhibits excellent structural stability and catalytic durability. In five consecutive cycles, the conversion rate of glucose showed extremely high stability, only slightly fluctuating from 99% initially to 98.9%, indicating that the catalyst has a robust framework structure and that the acidic active sites (B acid and L acid) are not easily lost or deactivated in the reaction system. The yield of the target product DFF remained above 59.10% in the first three cycles, showing good catalytic activity; by the fifth cycle, the yield dropped to 50.6%. Although the DFF yield fluctuated, the conversion rate of the raw material glucose remained at a high level of over 98%, proving that the acidic framework structure of the catalyst has excellent stability. The slow decrease in the DFF yield is mainly attributed to: (1) as the number of cycles increases, the trace amounts of humin-like byproducts generated in the reaction system undergo physical adsorption in the molecular sieve channels, which shields some of the oxidation active sites; (2) after multiple centrifugation and washing processes, the catalyst experienced slight mechanical loss and loss of metal species. Despite slight fluctuations in activity, the catalyst maintained a 98% conversion rate and a high DFF generation capacity after multiple cycles, demonstrating that the Nb-Ni@ZSM-5 catalyst has good potential for industrial application.

Claims

1. A method for preparing a catalyst for the production of 2,5-furandicarboxaldehyde from glucose, characterized in that, Includes the following steps: S1: Impregnation: The precursor solution of Nb and the precursor solution of Ni are mixed with ZSM-5 after high-temperature calcination in a muffle furnace using a co-impregnation method, and stirred at 40~80 ℃. S2: Oxidative roasting: After drying the material at 70~100 ℃, it is roasted at a constant temperature of 300~500 ℃ in an air atmosphere in a muffle furnace; S3: Reduction treatment: The roasted material is heated to 200~400 ℃ in a tube furnace under a reducing atmosphere of H2 for constant temperature reduction.

2. The method for preparing the catalyst for the production of 2,5-furandicarboxaldehyde from glucose according to claim 1, characterized in that, In step S1, the precursor of Nb is ammonium niobate oxalate hydrate, and the precursor of Ni is nickel nitrate hexahydrate.

3. The method for preparing the catalyst for the production of 2,5-furandicarboxaldehyde from glucose according to claim 1, characterized in that, The loading of Nb in the catalyst is 1-5 wt%, and the loading of Ni in the catalyst is 1-5 wt%.

4. The method for preparing the catalyst for the production of 2,5-furandicarboxaldehyde from glucose according to claim 1, characterized in that, The catalyst has a specific surface area of ​​257.48-304.67 m². 2 / g, with an average pore size of 2.39-2.87 nm and a pore volume of 0.15-0.22 cm³. 3 / g.

5. The method for preparing the catalyst for the production of 2,5-furandicarboxaldehyde from glucose according to claim 1, characterized in that, In step S2, the calcination temperature in the muffle furnace is 500 ℃.

6. The method for preparing the catalyst for the production of 2,5-furandicarboxaldehyde from glucose according to claim 1, characterized in that, In step S3, the calcination temperature of the tubular furnace is 400 ℃.

7. The catalyst prepared by the method according to any one of claims 1-6.

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