A method for producing 2,5-furan dicarboxylic acid using a manganese-doped nickel sulfide electrocatalyst at an industrial current density
By using a manganese-doped nickel sulfide electrocatalyst on a carbon felt support to electrocatalyze the oxidation of 5-hydroxymethylfurfural to produce 2,5-furandicarboxylic acid at industrial-grade current density, the problems of high cost, low current density, and environmental pollution in existing technologies have been solved, achieving efficient, green, and environmentally friendly FDCA production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- TAIZHOU RES INST ZHEJIANG UNIV OF TECH
- Filing Date
- 2022-12-09
- Publication Date
- 2026-05-15
AI Technical Summary
Existing FDCA synthesis processes suffer from problems such as high raw material and catalyst costs, complex production processes, low current density during electrolytic synthesis, and environmental pollution, making it difficult to meet the requirements for industrial-scale production.
2,5-furandicarboxylic acid was produced by electrocatalytic oxidation of 5-hydroxymethylfurfural using a manganese-doped nickel sulfide electrocatalyst at an industrial-grade current density. A three-dimensional carbon felt was used as a support, and the voltage and current were controlled by an electrochemical workstation. The reaction conditions were mild, and the products were separated by extraction with alkaline solution and organic solvent.
It achieves efficient and stable catalytic conversion of HMF to FDCA under high current density, with good product selectivity, high reaction yield, large throughput, short production cycle, green and environmentally friendly, and low cost.
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Figure CN116590724B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a method for synthesizing organic chemical products, and more particularly to a method for producing 2,5-furandicarboxylic acid using a manganese-doped nickel sulfide electrocatalyst at an industrial-grade current density. Background Technology
[0002] As a renewable non-fossil resource, biomass is considered a potential alternative to meet the stringent requirements of environmental protection and sustainable development. 5-Hydroxymethylfurfural (HMF) is an acid-catalyzed dehydration product of C6 carbohydrates, which is refined into fuels and chemicals with high energy density through catalytic oxidation, hydrogenation, and condensation reactions. 2,5-Furfurandicarboxylic acid (FDCA), oxidized from HMF, can serve as an important monomer in various polyesters of many bio-based polymers. Furthermore, the market demand for FDCA is continuously increasing due to the development of many new applications in recent years. Therefore, the synthesis of FDCA is very important. The main methods for synthesizing FDCA include chemical oxidation, biological oxidation, and electrochemical catalytic oxidation, most of which use HMF as a starting material. Chemical oxidation methods require sophisticated equipment, and the catalysts are mostly precious metals (such as Pt, Au, and Pd), which are expensive. At the same time, the reaction requires high temperatures (100-200℃) and long reaction times, making this preparation route unsuitable for the industrial production of FDCA. In the bio-oxidation method, bio-enzymes are used as catalysts. Due to the strict requirements of bio-enzymes on reaction conditions, deviations in reaction conditions will directly lead to a decrease in enzyme activity or even inactivation, which cannot meet the requirements for industrial production of FDCA.
[0003] In recent years, electrochemical catalytic oxidation (e-catalytic oxidation) has attracted widespread attention due to its mild reaction conditions, ease of control, cleanliness, and economy, showing promising application prospects. Currently, significant progress has been made in the electrocatalytic oxidation of HMF at <100 mA / cm². 2 At current densities above 500 mA / cm², the performance of many non-noble metal electrocatalysts has approached, or even surpassed, that of noble metal catalysts (Nat. Commun., 2022, 13, 3125; Chem. Mater., 2022, 34, 3123; ACS Energy Letters, 2016, 1, 386; J. Am. Chem. Soc., 2016, 138, 13639; Angew. Chem. Int. Ed., 2016, 55, 9913-9917). However, at current densities above 500 mA / cm², the performance of many non-noble metal electrocatalysts has reached or even surpassed that of noble metal catalysts (Nat. Commun., 2022, 13, 3125; Chem. Mater., 2022, 34, 3123; ACS Energy Letters, 2016, 1, 386; J. Am. Chem. Soc., 2016, 138, 13639; Angew. Chem. Int. Ed., 2016, 55, 9913-9917). 2 However, there are few reports on electrocatalysts that can efficiently and stably catalyze the conversion of HMF into the high-value-added chemical FDCA at high current densities. Therefore, breakthroughs in the preparation technology of high-performance electrocatalysts are of great significance for the electrocatalytic oxidation of HMF to FDCA. Summary of the Invention
[0004] The purpose of this invention is to overcome the problems of high cost of raw materials and catalysts, complex production process, low current density in electrolytic synthesis, and environmental pollution in the existing FDCA synthesis process. The invention provides a method for the electrocatalytic oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) under high current density. The process is green and environmentally friendly, the production process is simple, the catalyst cost is low, the product 2,5-furandicarboxylic acid has good selectivity, high reaction yield and throughput, and short production cycle.
[0005] A method for producing 2,5-furandicarboxylic acid using a manganese-doped nickel sulfide electrocatalyst at industrial-grade current densities involves controlling voltage and current using an electrochemical workstation and conducting the reaction in an H-type electrolytic cell. The cathode and anode chambers are separated by a cation exchange membrane. In the anode chamber, the manganese-doped nickel sulfide electrocatalyst serves as the working electrode. The manganese-doped nickel sulfide electrocatalyst comprises a three-dimensional carbon felt support and manganese-doped nickel sulfide supported on the carbon felt. 5-hydroxymethylfurfural is used as the reaction substrate dissolved in 0.1-2.0 mol / L water. The anode was prepared using an alkaline solution of 0.1-2.0 mol / L; in the cathode chamber, a platinum sheet was used as the counter electrode, and an alkaline solution of 0.1-2.0 mol / L was used as the cathode solution; the electrocatalytic oxidation reaction was carried out in a constant temperature water bath at 20-100℃, a current of 100-500 mA, and a cell voltage of 1-30 V for 10-300 minutes. After the reaction, the reaction solution was cooled and extracted with an organic solvent to obtain an organic extract. The organic layer was then distilled under normal pressure to obtain 2,5-furandicarboxylic acid. The reaction equation is as follows:
[0006]
[0007] Furthermore, the loading of the manganese-doped nickel sulfide on the carbon felt is 3-5 mg / cm³. 2 The size of the manganese-doped nickel sulfide electrocatalyst is 1×1 cm. 2 -5×5cm 2 Preferably 2×2cm 2 .
[0008] This invention defines a method for preparing the manganese-doped nickel sulfide electrocatalyst, comprising the following steps:
[0009] 1) According to the feeding ratio, dissolve the non-precious metal nickel raw material and manganese raw material in 50-100mL of water respectively, then add thiourea, and ultrasonically disperse at room temperature for 30 minutes. This is called solution A. The non-precious metal nickel raw material is nickel nitrate, nickel chloride, nickel acetylacetonate or nickel acetate; the manganese raw material is manganese nitrate, manganese acetate, manganese tetroxide or manganese acetylacetonate; the molar ratio of manganese raw material to nickel raw material is 1:10-5:10, and the molar ratio of non-precious metal nickel to thiourea is 1:1-1:5.
[0010] 2) Add solution A and the carbon felt support from step 1) to a hydrothermal reactor and react hydrothermally at 80-240℃ for 5-24 hours. After the reaction is complete, cool to room temperature, remove the carbon felt support, wash with distilled water and ethanol, and then vacuum dry at 60℃ to obtain the manganese-doped nickel sulfide electrocatalyst, abbreviated as Mn. x -NiS / GF (x is 0.1 to 0.5).
[0011] Preferably, in step 1), the non-precious metal nickel raw material is nickel nitrate, and the manganese raw material is a 50% aqueous solution of manganese nitrate; in step 2), the hydrothermal temperature is 120-180℃, and the hydrothermal time is 10-16 hours.
[0012] Furthermore, the volume of both the cathode chamber and the anode chamber is 10-100 mL; the volume of the anolyte used is 50-500 mmol / L, calculated based on the concentration of 5-hydroxymethylfurfural.
[0013] Preferably, the volume of the anolyte used is 50-100 mmol / L, calculated based on the concentration of 5-hydroxymethylfurfural.
[0014] The alkaline solution is a potassium hydroxide solution, sodium hydroxide solution, sodium carbonate solution, or sodium bicarbonate solution, with a concentration of 0.5-1.0 mol / L.
[0015] Preferably, during the electrocatalytic oxidation reaction, the current is 100-500mA, the cell voltage is 2-10V, the reaction temperature is 20-50℃, and the reaction time is 20-200 minutes.
[0016] Furthermore, the organic solvent used for extraction is ethyl acetate, dichloromethane, chloroform, or toluene.
[0017] By employing the above-described technology, the beneficial effects achieved by the present invention compared to the prior art are as follows:
[0018] (1) The three-dimensional graphite felt used in the process of the present invention is used as a carrier for loading metal. Since graphite felt has high electronic conductivity, large specific surface area and high structural stability, when metal is loaded on graphite felt, the conductivity of electrocatalyst is greatly improved, so that its HMF electro-oxidation reaction can obtain high current density.
[0019] (2) The manganese-doped nickel sulfide electrocatalyst used in this invention has a large number of active sites on its surface, which are beneficial to the adsorption of the reaction substrate HMF and the desorption of the product FDCA.
[0020] (3) The process method of the present invention has mild electrocatalytic oxidation reaction conditions, is green and pollution-free, and optimizes Mn. 0.2The NiS / GF electrocatalyst yielded a high HMF conversion rate of 98%, a good FDCA yield (97%), and a high Faraday efficiency (94%).
[0021] (4) This invention operates at 500 mA / cm 2 The HMF electrocatalytic oxidation was carried out at an industrial-grade current density with a fast reaction rate and a very short reaction time, and the synthesized FDCA flux reached 4.5 g / h, which is higher than the HMF electrocatalytic oxidation performance reported to date.
[0022] (5) The present invention uses water as a reaction solvent, which is low in cost. The alkaline reaction solution can be reused and does not produce harmful gases or harmful waste liquids. Therefore, the method has low toxicity, is green and environmentally friendly, and the reaction is easy to control. Attached Figure Description
[0023] Figure 1a Mn in Example 1 0.2 SEM image of NiS / GF catalyst at 2 μm;
[0024] Figure 1b Mn in Example 1 0.2 SEM image of NiS / GF catalyst at 200 nm;
[0025] Figure 1c The graph shows the change in the reaction of electrocatalytic oxidation of HMF to FDCA in Example 1 over time. Detailed Implementation
[0026] The technical solution of the present invention will be further described in detail below through specific embodiments and in conjunction with the accompanying drawings.
[0027] Example 1: Mn 0.2 Synthesis of NiS / GF catalyst and its electrocatalytic oxidation of HMF to FDCA
[0028] (1) According to the feeding ratio, take 582mg of nickel nitrate, 72mg of manganese nitrate aqueous solution (mass concentration 50%) and 152mg of thiourea respectively and dissolve them in 80mL of water. Disperse them ultrasonically at room temperature for 30 minutes. This solution is called A.
[0029] (2) Combine solution A from step (1) with a carbon felt carrier (approximately 2×3cm in size). 2 The carbon felt was added to a hydrothermal reactor and reacted hydrothermally at 140°C for 14 hours. After cooling to room temperature, the carbon felt was removed, washed twice alternately with distilled water and ethanol, and then vacuum dried at 60°C to obtain the manganese-doped nickel sulfide electrocatalyst, labeled as Mn. 0.2 -NiS / GF. Scanning electron microscope (SEM) image as shown. Figure 1a and 1bAs shown. From Figure 1a , Figure 1b It can be found that Mn 0.2 -NiS / GF catalysts exhibit a nanosheet morphology.
[0030] The Mn prepared in Example 1 0.2 The catalytic performance of the NiS / GF catalyst was tested using the following method: Mn 0.2 -NiS / GF catalyst trimming is approximately 1×1cm 2 The size is directly used as the working electrode. The current is controlled by a galvanometer, and the reaction is carried out in an H-type electrolytic cell. The anode and cathode chambers are 10 mL in volume and separated by a cation exchange membrane. 10 mL of 1.0 mol / L KOH aqueous solution is used as the electrolyte solution for both the anode and cathode chambers. In the anode chamber of the electrolytic cell, the prepared Mn... 0.2 -NiS / GF catalyst is used as the working electrode; in the cathode chamber of the electrolyzer, a platinum electrode is used as the counter electrode;
[0031] S1: Using HMF (5-hydroxymethylfurfural) as a reactant, add 126 mg of HMF to the electrolyte solution in the anode chamber;
[0032] S2: Place the entire electrolytic cell in a constant temperature water bath to control the reaction system temperature at 20℃, stir, control the current at 500mA, control the voltage range at 2-5V, and react for 20 minutes.
[0033] S3: After cooling the anolyte solution from step S2 to room temperature, it is extracted with dichloromethane to separate the layers. The dichloromethane phase is then evaporated and separated to obtain the FDCA product. The reaction results are tested as the reaction time progresses. Figure 1c As shown. Figure 1c This graph shows the changes in the raw material HMF and its oxidation products over time. HMF is the raw material, FDCA is the main product, and 2,5-furandicarboxaldehyde (DFF), 5-hydroxymethyl-2-furancarboxylic acid (HMFCA), or 5-formylfuran-2-carboxylic acid (FFCA) are the byproducts. Figure 1c It can be seen that as the reaction time increases, the amount of raw material HMF gradually decreases, while the amount of main product FDCA gradually increases. Specifically, when the reaction reaches 20 minutes, the conversion rate of HMF is 98%, the yield of FDCA is 97%, the calculated Faraday efficiency reaches 94%, and the flux of FDCA is 4.5 g / h.
[0034] Example 2: Mn 0.1 Synthesis of NiS / GF catalyst and its electrocatalytic oxidation of HMF to FDCA
[0035] (1) According to the feeding ratio, take 582mg of nickel nitrate, 36mg of manganese nitrate aqueous solution (mass concentration 50%) and 304mg of thiourea respectively and dissolve them in 50mL of water. Disperse them ultrasonically at room temperature for 30 minutes. This solution is called A.
[0036] (2) Combine solution A from step (1) with a carbon felt carrier (approximately 2×2cm in size). 2 The carbon felt was added to a hydrothermal reactor and reacted hydrothermally at 120°C for 16 hours. After cooling to room temperature, the carbon felt was removed, washed twice alternately with distilled water and ethanol, and then vacuum dried at 60°C to obtain the manganese-doped nickel sulfide electrocatalyst, labeled as Mn. 0.1 -NiS / GF.
[0037] The Mn prepared in Example 2 0.1 The catalytic performance of the NiS / GF catalyst was tested using the following method: Mn 0.1 -NiS / GF catalyst trimming is approximately 1×1cm 2 The size is directly used as the working electrode. The current is controlled by a galvanometer, and the reaction is carried out in an H-type electrolytic cell. The anode and cathode chambers are 20 mL in volume and separated by a cation exchange membrane. 20 mL of 0.5 mol / L KOH aqueous solution is used as the electrolyte solution for both the anode and cathode chambers. In the anode chamber of the electrolytic cell, the prepared Mn... 0.1 -NiS / GF catalyst is used as the working electrode; in the cathode chamber of the electrolyzer, a platinum electrode is used as the counter electrode;
[0038] S1: Using HMF (5-hydroxymethylfurfural) as a reactant, add 252 mg of HMF to the electrolyte solution in the anode chamber;
[0039] S2: Place the entire electrolytic cell in a constant temperature water bath to control the reaction system temperature at 30℃, stir, control the current at 500mA, control the voltage range at 2-10V, and react for 50 minutes.
[0040] S3: After cooling the electrolyte solution in the anode chamber of step S2 to room temperature, it is extracted and separated by ethyl acetate. The ethyl acetate phase is then evaporated and separated to obtain the FDCA product. When the reaction reaches 50 minutes, the conversion rate of HMF is 93%, the yield of FDCA is 90%, the calculated Faraday efficiency is 87%, and the flux of FDCA is 4.1 g / h.
[0041] Example 3: Mn 0.3 Synthesis of NiS / GF catalyst and its electrocatalytic oxidation of HMF to FDCA
[0042] (1) According to the feeding ratio, take 582mg of nickel nitrate, 107mg of manganese nitrate aqueous solution (mass concentration 50%) and 152mg of thiourea respectively and dissolve them in 70mL of water. Disperse them ultrasonically at room temperature for 30 minutes. This solution is called A.
[0043] (2) Combine solution A from step (1) with a carbon felt carrier (approximately 1×2cm in size). 2 The carbon felt was added to a hydrothermal reactor and reacted hydrothermally at 120°C for 14 hours. After cooling to room temperature, the carbon felt was removed, washed twice alternately with distilled water and ethanol, and then vacuum dried at 60°C to obtain the manganese-doped nickel sulfide electrocatalyst, labeled as Mn. 0.3 -NiS / GF.
[0044] The Mn prepared in Example 3 0.3 The catalytic performance of the NiS / GF catalyst was tested using the following method: Mn 0.3 -NiS / GF catalyst trimming is approximately 1×1cm 2 The size is directly used as the working electrode. The current is controlled by a galvanometer, and the reaction is carried out in an H-type electrolytic cell. The anode and cathode chambers are 15 mL in volume and separated by a cation exchange membrane. 10 mL of 1.0 mol / L KOH aqueous solution is used as the electrolyte solution for both the anode and cathode chambers. In the anode chamber of the electrolytic cell, the prepared Mn... 0.3 -NiS / GF catalyst is used as the working electrode; in the cathode chamber of the electrolyzer, a platinum electrode is used as the counter electrode;
[0045] S1: Using HMF (5-hydroxymethylfurfural) as a reactant, add 126 mg of HMF to the electrolyte solution in the anode chamber;
[0046] S2: Place the entire electrolytic cell in a constant temperature water bath to control the reaction system temperature at 40℃, stir, control the current at 500mA, control the voltage range at 2-10V, and react for 25 minutes.
[0047] S3: After cooling the electrolyte solution in the anode chamber of step S2 to room temperature, it is extracted and separated by dichloromethane. The dichloromethane phase is then evaporated and separated to obtain the FDCA product. When the reaction reaches 25 minutes, the conversion rate of HMF is 96%, the yield of FDCA is 94%, the calculated Faraday efficiency is 92%, and the flux of FDCA is 4.3 g / h.
[0048] Example 4: Mn 0.4 Synthesis of NiS / GF catalyst and its electrocatalytic oxidation of HMF to FDCA
[0049] (1) According to the feeding ratio, take 582mg of nickel nitrate, 143mg of manganese nitrate aqueous solution (mass concentration 50%) and 456mg of thiourea respectively and dissolve them in 80mL of water. Disperse them ultrasonically at room temperature for 30 minutes. This solution is called A.
[0050] (2) Combine solution A from step (1) with a carbon felt carrier (approximately 2×2cm in size). 2 The carbon felt was added to a hydrothermal reactor and reacted hydrothermally at 140°C for 10 hours. After cooling to room temperature, the carbon felt was removed, washed twice alternately with distilled water and ethanol, and then vacuum dried at 60°C to obtain the manganese-doped nickel sulfide electrocatalyst, labeled as Mn. 0.4 -NiS / GF.
[0051] The Mn prepared in Example 4 0.4 The catalytic performance of the NiS / GF catalyst was tested using the following method: Mn 0.4 -NiS / GF catalyst trimming is approximately 1×1cm 2 The size is directly used as the working electrode. The current is controlled by a galvanometer, and the reaction is carried out in an H-type electrolytic cell. The anode and cathode chambers are 50 mL in volume and separated by a cation exchange membrane. 50 mL of 0.5 mol / L KOH aqueous solution is used as the electrolyte solution for both the anode and cathode chambers. In the anode chamber of the electrolytic cell, the prepared Mn... 0.4 -NiS / GF catalyst is used as the working electrode; in the cathode chamber of the electrolyzer, a platinum electrode is used as the counter electrode;
[0052] S1: Using HMF (5-hydroxymethylfurfural) as a reactant, add 630 mg of HMF to the electrolyte solution in the anode chamber;
[0053] S2: Place the entire electrolytic cell in a constant temperature water bath to control the reaction system temperature at 50℃, stir, control the current at 500mA, control the voltage range at 2-10V, and react for 110 minutes.
[0054] S3: After cooling the electrolyte solution in the anode chamber of step S2 to room temperature, it is extracted and separated by dichloromethane. The dichloromethane phase is then evaporated and separated to obtain the FDCA product. When the reaction reaches 110 minutes, the conversion rate of HMF is 95%, the yield of FDCA is 93%, the calculated Faraday efficiency is 89%, and the flux of FDCA is 3.9 g / h.
[0055] Example 5: Mn 0.5 Synthesis of NiS / GF catalyst and its electrocatalytic oxidation of HMF to FDCA
[0056] (1) According to the feeding ratio, take 582mg of nickel nitrate, 179mg of manganese nitrate aqueous solution (mass concentration 50%) and 760mg of thiourea respectively and dissolve them in 80mL of water. Disperse them ultrasonically at room temperature for 30 minutes, and call it solution A;
[0057] (2) Combine solution A from step (1) with a carbon felt carrier (approximately 2×2cm in size). 2 The carbon felt was added to a hydrothermal reactor and reacted hydrothermally at 120°C for 16 hours. After cooling to room temperature, the carbon felt was removed, washed twice alternately with distilled water and ethanol, and then vacuum dried at 60°C to obtain the manganese-doped nickel sulfide electrocatalyst, labeled as Mn. 0.5 -NiS / GF.
[0058] The Mn prepared in Example 5 0.5 The catalytic performance of the NiS / GF catalyst was tested using the following method: Mn 0.5 -NiS / GF catalyst trimming is approximately 1×1cm 2 The size is directly used as the working electrode. The current is controlled by a galvanometer, and the reaction is carried out in an H-type electrolytic cell. The anode and cathode chambers are 100 mL in volume and separated by a cation exchange membrane. A 100 mL solution of 1.0 mol / L KOH is used as the electrolyte solution for both the anode and cathode chambers. In the anode chamber of the electrolytic cell, the prepared Mn... 0.5 -NiS / GF catalyst is used as the working electrode; in the cathode chamber of the electrolyzer, a platinum electrode is used as the counter electrode;
[0059] S1: Using HMF (5-hydroxymethylfurfural) as a reactant, add 1260 mg of HMF to the electrolyte solution in the anode chamber;
[0060] S2: Place the entire electrolytic cell in a constant temperature water bath to control the reaction system temperature at 30℃, stir, control the current at 500mA, control the voltage range at 2-10V, and react for 200 minutes.
[0061] S3: After cooling the electrolyte solution in the anode chamber of step S2 to room temperature, it is extracted and separated by dichloromethane. The dichloromethane phase is then evaporated and separated to obtain the FDCA product. When the reaction time reaches 200 minutes, the conversion rate of HMF is 92%, the yield of FDCA is 88%, the calculated Faraday efficiency is 86%, and the flux of FDCA is 3.7 g / h.
[0062] Example 6: Synthesis of NiS / GF catalyst and its electrocatalytic oxidation of HMF to FDCA
[0063] (1) According to the feeding ratio, 582 mg of nickel nitrate and 152 mg of thiourea were dissolved in 80 mL of water and ultrasonically dispersed at room temperature for 30 minutes, which is called solution A;
[0064] (2) Combine solution A from step (1) with a carbon felt carrier (approximately 2×3cm in size). 2 The carbon felt was added to a hydrothermal reactor and reacted hydrothermally at 140°C for 14 hours. After cooling to room temperature, the carbon felt was removed, washed twice alternately with distilled water and ethanol, and then dried under vacuum at 60°C to obtain the manganese-doped nickel sulfide electrocatalyst, labeled as NiS / GF.
[0065] The catalytic performance of the NiS / GF catalyst prepared in Example 6 was tested using the following methods:
[0066] The NiS / GF catalyst was cut to approximately 1×1 cm. 2 The catalyst, of which the catalyst is sized, is used directly as the working electrode. The current is controlled by a galvanometer, and the reaction is carried out in an H-type electrolytic cell. The anode and cathode chambers are 10 mL in volume and separated by a cation exchange membrane. A 10 mL 1.0 mol / L KOH aqueous solution is used as the electrolyte solution for both the anode and cathode chambers. In the anode chamber, the prepared NiS / GF catalyst is used as the working electrode; in the cathode chamber, a platinum electrode is used as the counter electrode.
[0067] S1: Using HMF (5-hydroxymethylfurfural) as a reactant, add 126 mg of HMF to the electrolyte solution in the anode chamber;
[0068] S2: Place the entire electrolytic cell in a constant temperature water bath to control the reaction system temperature at 20℃, stir, control the current at 500mA, control the voltage range at 2-5V, and react for 20 minutes.
[0069] S3: After cooling the electrolyte solution in the anode chamber of step S2 to room temperature, it is extracted and separated by dichloromethane. The dichloromethane phase is then evaporated and separated to obtain the FDCA product. When the reaction reaches 20 minutes, the conversion rate of HMF is 86%, the yield of FDCA is 84%, the calculated Faraday efficiency is 82%, and the flux of FDCA is 3.2 g / h.
[0070] Example 7: Synthesis of Ni / GF catalyst and its electrocatalytic oxidation of HMF to FDCA
[0071] (1) According to the feeding ratio, 582 mg of nickel nitrate was dissolved in 50 mL of water and ultrasonically dispersed at room temperature for 30 minutes, which is called solution A;
[0072] (2) Combine solution A from step (1) with a carbon felt carrier (approximately 2×3cm in size). 2 The carbon felt was added to a hydrothermal reactor and reacted hydrothermally at 140°C for 14 hours. After cooling to room temperature, the carbon felt was removed, washed twice alternately with distilled water and ethanol, and then dried under vacuum at 60°C to obtain the manganese-doped nickel sulfide electrocatalyst, labeled as Ni / GF.
[0073] The catalytic performance of the Ni / GF catalyst prepared in Example 7 was tested using the following methods:
[0074] The Ni / GF catalyst was cut to approximately 1×1 cm. 2 The size of the electrode is directly used as the working electrode. The current is controlled by a galvanometer, and the reaction is carried out in an H-type electrolytic cell. The anode and cathode chambers are 10 mL in volume and separated by a cation exchange membrane. A 10 mL 1.0 mol / L KOH aqueous solution is used as the electrolyte solution for both the anode and cathode chambers. In the anode chamber, the prepared Ni / GF catalyst is used as the working electrode; in the cathode chamber, a platinum electrode is used as the counter electrode.
[0075] S1: Using HMF (5-hydroxymethylfurfural) as a reactant, add 126 mg of HMF to the electrolyte solution in the anode chamber;
[0076] S2: Place the entire electrolytic cell in a constant temperature water bath to control the reaction system temperature at 20℃, stir, control the current at 500mA, control the voltage range at 2-5V, and react for 20 minutes.
[0077] S3: After cooling the electrolyte solution in the anode chamber of step S2 to room temperature, it is extracted and separated by dichloromethane. The dichloromethane phase is then evaporated and separated to obtain the FDCA product. When the reaction reaches 20 minutes, the conversion rate of HMF is 82%, the yield of FDCA is 78%, the calculated Faraday efficiency is 76%, and the flux of FDCA is 2.8 g / h.
[0078] For the electrocatalytic oxidation of HMF to FDCA, compared with the seven catalysts prepared above (Mn 0.2 -NiS / GF, Mn 0.1 -NiS / GF, Mn 0.3 -NiS / GF, Mn 0.4 -NiS / GF, Mn 0.5 -NiS / GF, NiS / GF, Ni / GF), the results are shown in Table 1.
[0079] Table 1 Catalytic effects of catalysts in Examples 1-7
[0080]
[0081] As shown in Table 1, compared with Examples 6 and 7, Example 1 of the present invention exhibits superior catalytic performance, with an FDCA flux as high as 4.5 g / h. This indicates that Mn doping significantly enhances the activity of the NiS electrocatalyst, which may be due to Mn promoting the activity of NiS. 2+ Ni is first formed during electrocatalytic oxidation. 3+The (NiOOH) intermediate state makes it easier for the substrate HMF to be adsorbed on the catalyst surface for electrocatalytic oxidation, and the product FDCA is then desorbed from the surface after the reaction.
[0082] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Other variations and modifications are possible without departing from the technical solutions described in the claims.
Claims
1. A method for preparing 2,5-furandicarboxylic acid using a manganese-doped nickel sulfide electrocatalyst at an industrial-grade current density, characterized in that... The voltage and current are controlled by an electrochemical workstation, and the reaction is carried out in an H-type electrolytic cell. The cathode chamber and the anode chamber are separated by a cation exchange membrane. In the anode chamber, a manganese-doped nickel sulfide electrocatalyst is used as the working electrode. The manganese-doped nickel sulfide electrocatalyst is composed of a three-dimensional carbon felt support and manganese-doped nickel sulfide supported on the carbon felt. 5-hydroxymethylfurfural is used as the reaction substrate and dissolved in an alkaline solution of 0.1-2.0 mol / L as the anolyte. In the cathode chamber, a platinum sheet serves as the counter electrode, and a 0.1-2.0 mol / L alkaline solution is used as the catholyte. The electrocatalytic oxidation reaction is carried out in a constant-temperature water bath at 20-100℃, a current of 100-500 mA, and a cell voltage of 1-30 V for 10-300 minutes. After the reaction, the reaction solution is cooled and extracted with an organic solvent to obtain an organic extract. The organic layer is then distilled under normal pressure to obtain 2,5-furandicarboxylic acid. The reaction equation is as follows: 。 2. The method for preparing 2,5-furandicarboxylic acid at industrial-grade current density using a manganese-doped nickel sulfide electrocatalyst according to claim 1, characterized in that... The loading of the manganese-doped nickel sulfide on the carbon felt is 3-5 mg / cm³. 2 .
3. The method for preparing 2,5-furandicarboxylic acid at industrial-grade current density using a manganese-doped nickel sulfide electrocatalyst according to claim 2, characterized in that... The preparation method of the manganese-doped nickel sulfide electrocatalyst includes the following steps: 1) According to the feeding ratio, dissolve the non-precious metal nickel raw material and manganese raw material in 50-100mL of water respectively, then add thiourea, and ultrasonically disperse at room temperature for 30 minutes. This is called solution A. The non-precious metal nickel raw material is nickel nitrate, nickel chloride, nickel acetylacetonate or nickel acetate; the manganese raw material is manganese nitrate, manganese acetate, manganese tetroxide or manganese acetylacetonate; the molar ratio of manganese raw material to nickel raw material is 1:10-5:10, and the molar ratio of non-precious metal nickel to thiourea is 1:1-1:
5. 2) Add solution A and carbon felt support from step 1) into a hydrothermal reactor and react hydrothermally at 80-240℃ for 5-24 hours. After the reaction is completed, cool to room temperature, remove the carbon felt support, wash with distilled water and ethanol, and then vacuum dry at 60℃ to obtain the manganese-doped nickel sulfide electrocatalyst.
4. The method for preparing 2,5-furandicarboxylic acid at an industrial-grade current density using a manganese-doped nickel sulfide electrocatalyst according to claim 3, characterized in that: In step 1), the non-precious metal nickel raw material is nickel nitrate, and the manganese raw material is a 50% manganese nitrate aqueous solution. In step 2), the hydrothermal temperature is 120-180 ℃ and the hydrothermal time is 10-16 hours.
5. A method for producing 2,5-furandicarboxylic acid at an industrial-grade current density using a manganese-doped nickel sulfide electrocatalyst according to claim 1 or 2, characterized in that... The volume of both the cathode and anode chambers is 10-100 mL; the volume of anolyte used is 50-500 mmol / L, calculated based on the concentration of 5-hydroxymethylfurfural.
6. The method for preparing 2,5-furandicarboxylic acid at industrial-grade current density using a manganese-doped nickel sulfide electrocatalyst according to claim 5, characterized in that... The volume of anolyte used is 50-100 mmol / L, calculated based on the concentration of 5-hydroxymethylfurfural.
7. A method for preparing 2,5-furandicarboxylic acid at an industrial-grade current density using a manganese-doped nickel sulfide electrocatalyst according to claim 1 or 2, characterized in that... The alkaline solution is a potassium hydroxide solution, sodium hydroxide solution, sodium carbonate solution, or sodium bicarbonate solution, with a concentration of 0.5-1.0 mol / L.
8. A method for preparing 2,5-furandicarboxylic acid at an industrial-grade current density using a manganese-doped nickel sulfide electrocatalyst according to claim 1 or 2, characterized in that... When performing electrocatalytic oxidation, the current is 100-500 mA, the cell voltage is 2-10 V, the reaction temperature is 20-50 ℃, and the reaction time is 20-200 minutes.
9. A method for preparing 2,5-furandicarboxylic acid at an industrial-grade current density using a manganese-doped nickel sulfide electrocatalyst according to claim 1 or 2, characterized in that... The organic solvent used for extraction is ethyl acetate, dichloromethane, chloroform, or toluene.