Catalyst for catalytic synthesis of 2, 5-furandicarboxylic acid, preparation method and application

Abstract

The invention discloses a catalyst for catalytic synthesis of 2, 5-furandicarboxylic acid as well as a preparation method and application of the catalyst, and the preparation method of the catalyst comprises the following steps: (1) obtaining a molecular sieve modified by nitrogen species as a catalyst carrier; and (2) mixing transition metal salt with the molecular sieve modified by nitrogen species, and roasting at high temperature to obtain the transition metal oxide catalyst coated with the nitrogen modified molecular sieve. The 2, 5-furandicarboxylic acid is prepared by using 5-hydroxymethylfurfural as a raw material and using the catalyst for catalytic oxidation in a containing atmosphere, the method is simple to operate and mild in condition, the catalyst has high stability and good reusability, and the production process of the 2, 5-furandicarboxylic acid is economical and environment-friendly.

Description

Technical Field

[0001] The invention relates to a catalyst for catalytically synthesizing 2,5-furandicarboxylic acid, a preparation method and application thereof, and belongs to the field of chemistry and chemical engineering. Background Art

[0002] Biomass is a renewable organic carbon resource widely found in nature. The development of efficient catalytic conversion technology to convert biomass resources into high-value chemicals is of great significance for achieving sustainable development. 5-Hydroxymethylfurfural (HMF) is an important bio-based platform molecule that can be prepared by hydrolysis, isomerization and dehydration of cellulose and hemicellulose. The selective oxidation product of HMF, 2,5-furandicarboxylic acid (FDCA), has a unique furan ring structure and dicarboxylic acid functional group, and is an important monomer for the synthesis of bio-based polyethylene 2,5-furandicarboxylate (PEF). It is worth noting that PEF has similar structural characteristics to traditional petroleum-based polyethylene terephthalate (PET), and has excellent biodegradability and gas barrier properties. It has passed the EU food safety certification and shows broad application prospects in packaging materials and other fields. Therefore, it is of great research and application value to design an efficient catalytic process to achieve efficient and highly selective oxidation of biomass-based raw material HMF to prepare FDCA. At present, the process of preparing HMF from biomass raw materials such as cellulose and glucose has become relatively mature, which has laid a solid foundation for establishing a new process for catalytic oxidation of HMF to synthesize FDCA based on the biomass route.

[0003] In the traditional synthesis process, HMF oxidation to prepare FDCA mainly adopts stoichiometric oxidation and homogeneous oxidation. The stoichiometric oxidation method usually uses KMnO 4 、N 2 O 4 , HNO 3 However, these oxidants are not only highly corrosive to the reaction equipment, but also produce a large amount of pollutants, which is not in line with the principles of green chemistry. 2+ / Mn 2+ / Br - or Co 2 + / Zn 2+ / Br - Catalytic system, using oxygen-containing gas as oxidant; although this method avoids the use of stoichiometric oxidant, the FDCA yield is generally low, the metal ions in the catalyst system are difficult to effectively recover, the bromine co-catalyst is highly corrosive, and toxic brominated byproducts are produced. These technical bottlenecks restrict the industrial application of traditional HMF oxidation process.

[0004] Compared with stoichiometric oxidation and homogeneous catalytic methods, heterogeneous catalytic oxidation has significant advantages in product separation, catalyst recycling, catalytic efficiency and environmental friendliness. As an ideal heterogeneous catalyst carrier, molecular sieve materials can effectively disperse and stabilize metal active components by coating and confinement, and can accurately control reaction selectivity and significantly improve catalytic performance. Therefore, the development of transition metal catalysts based on molecular sieve carriers is expected to provide an efficient and economical catalytic solution for HMF oxidation reactions. The acid-base properties of molecular sieves can be regulated by organic functionalization modification, and suitable conditions can be created for the loading and coating of metal active components. Based on this, the precise design of the molecular sieve pore microenvironment to construct transition metal active centers, synthesize catalysts with high stability and high activity, and then achieve highly selective catalytic oxidation of HMF has become a research hotspot in the current catalysis field and has received widespread attention. Summary of the invention

[0005] According to one aspect of the present invention, a method for preparing a catalyst for catalytic synthesis of 2,5-furandicarboxylic acid is provided, wherein a molecular sieve is modified by a nitrogen-containing organic matter, and then a metal active component is introduced to obtain a transition metal oxide catalyst coated with a nitrogen-modified molecular sieve. In the present invention, the metal oxide active component in the catalyst structure is coated in the pores of the molecular sieve to form a uniformly dispersed nanostructure to improve the stability and catalytic activity of the catalyst. The catalyst can efficiently catalytically oxidize 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid in an oxygen-containing atmosphere and under mild conditions.

[0006] The carrier of the molecular sieve-coated transition metal oxide catalyst is at least one of SBA-15, TS-1, ZSM-5, MCM-41, KIT-6, Beta or HY molecular sieves; the active component of the transition metal oxide is iron oxide (Fe x O y ), cobalt oxide (Co x O y ), copper oxide (Cu x O y ), manganese oxide (Mn x O y ) or vanadium oxide (V x O y ), derived from at least one of nitrates, sulfates, acetates, and acetylacetonates of transition metals of iron, cobalt, copper, manganese, and vanadium; the nitrogen-modified structure of the catalyst is derived from 2,2'-bipyridine, 2,2'-bipyridylamine, terpyridine, o-phenanthroline, dicyandiamide, melamine, urea, triethylamine, ethylenediamine, diethylenetriamine, acrylamide, lysine, histidine, or C 3 N 4 At least one of .

[0007] The transition metal oxide component in the catalyst is uniformly dispersed and has a nanometer size between 5 and 50 nm; the loading amount of the metal component in the catalyst is 3.0 wt% to 30.0 wt%.

[0008] The molecular sieve-coated transition metal oxide catalyst is obtained by an impregnation-pyrolysis method or a ball milling-pyrolysis method, and the specific preparation steps are as follows: (1) adding the dealuminated molecular sieve to a solution of nitrogen-containing organic matter, heating and stirring, then removing the solvent, and performing high-temperature pyrolysis in an inert atmosphere to obtain a nitrogen-modified molecular sieve; (2) adding the nitrogen-modified molecular sieve to a solution containing a transition metal salt, after ultrasonic treatment, heating and stirring, loading the metal component, then removing the solvent, using a muffle furnace, calcining in an air atmosphere to obtain the nitrogen-modified molecular sieve-coated transition metal oxide catalyst; optionally, the nitrogen-modified molecular sieve is directly mixed with the transition metal salt, ball milled in a ball mill, the two are uniformly mixed, and then calcined in an air atmosphere to obtain the nitrogen-modified molecular sieve-coated transition metal oxide catalyst.

[0009] The concentration of the nitrogen-containing organic matter in step (1) is 0.2-2M; the mass ratio of the nitrogen-containing organic matter to the molecular sieve is 0.1-1; the stirring temperature is 25-80°C, and the stirring time is 0.5-10h; the pyrolysis temperature is 300-500°C, and the pyrolysis time is 1-5h.

[0010] The concentration of the transition metal salt solution in step (2) is 0.01-0.1M; the mass ratio of the transition metal salt to the nitrogen-doped molecular sieve is 0.1-0.5; the stirring temperature is 25-60°C, and the stirring time is 2-10h; the ball milling time is 2-10h, and the temperature is room temperature; the calcination temperature is 400-800°C, and the calcination time is 1-5h.

[0011] The method for removing the solvent in steps (1) and (2) is to remove the solvent by rotary evaporation.

[0012] The above catalyst synthesis conditions are mild and easy to operate. The catalyst obtained by the above technology is low-cost, stable in performance, and has good reusability and recyclability.

[0013] The second aspect of the present invention provides an application method for synthesizing 2,5-furandicarboxylic acid using the above-mentioned catalyst, comprising: in a kettle reactor or a round-bottom flask, contacting a nitrogen-modified molecular sieve-coated transition metal oxide catalyst with a raw material 5-hydroxymethylfurfural, reacting and acidifying in the presence of an alkaline additive, water and an oxygen-containing atmosphere to obtain 2,5-furandicarboxylic acid.

[0014] The molar concentration of the 5-hydroxymethylfurfural is 0.5-1.5 mol / L.

[0015] The alkaline additive is LiOH, Li 2 CO 3 , CH 3 COOLi, NaOH, Na 2 CO 3 、NaHCO 3 , CH 3 COONa, KOH, K 2 CO 3 , KHCO 3 , CH 3 At least one of COOK; the molar ratio of the alkaline additive to 5-hydroxymethylfurfural is 1:1 to 4:1.

[0016] The molar ratio of the metal component of the catalyst to 5-hydroxymethylfurfural is 0.05:1 to 0.2:1.

[0017] The oxygen-containing atmosphere is oxygen or air. The oxygen-containing atmosphere is added in the following ways: introducing the oxygen-containing atmosphere into the reaction system at a gas pressure of normal pressure to 2.0 MPa; introducing the oxygen-containing atmosphere by bubbling at a gas flow rate of 5 to 60 mL / min.

[0018] The reaction temperature is 50-120° C. and the reaction time is 5-12 hours.

[0019] The acidification process uses sulfuric acid or hydrochloric acid aqueous solution with a concentration of 0.1 to 1 M and an acidification time of 5 to 30 minutes.

[0020] According to the present invention, a molecular sieve-coated transition metal oxide catalyst is used, air or oxygen is used as an oxygen source, and the reaction is carried out for 5 to 12 hours at a reaction temperature of 50 to 120° C. and a reaction pressure of normal pressure to 2.0 MPa, so that 5-hydroxymethylfurfural is efficiently and highly selectively catalytically oxidized to 2,5-furandicarboxylic acid, and the conversion rate of 5-hydroxymethylfurfural and the yield of 2,5-furandicarboxylic acid both reach more than 90%.

[0021] In the present invention, the prepared catalyst can catalyze the oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid in green solvent water with oxygen or air as an oxidant, and the conversion rate of 5-hydroxymethylfurfural and the yield of 2,5-furandicarboxylic acid are both above 90%. The method is simple to operate and has mild conditions; the product separation process is simple, efficient and low-cost, and is a new method for preparing 2,5-furandicarboxylic acid based on biomass-based raw materials, which has good application prospects.

[0022] The beneficial effects that the present invention can produce include: (1) The catalyst prepared by the preparation method provided by the present invention encapsulates the metal oxide in the pores of the nitrogen-modified molecular sieve, and the metal species exists in the form of nanoparticles, which has stability and high activity during the reaction process; (2) The present invention uses a transition metal catalyst coated with a nitrogen-modified molecular sieve to achieve efficient catalytic oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid under mild conditions, saving energy consumption and reducing product separation costs; (3) The preparation method provided by the present invention has the advantages of low transition metal catalyst production cost and small amount of use; (4) The catalyst preparation method and the application method for synthesizing 2,5-furandicarboxylic acid provided by the present invention are innovative and have strong promotion and application value. DETAILED DESCRIPTION

[0023] The present invention is described in detail below in conjunction with embodiments, but the present invention is not limited to these embodiments.

[0024] Unless otherwise specified, the raw materials in the examples of the present invention were purchased from commercial sources.

[0025] In the embodiments of the present invention, the raw material conversion rate and product selectivity are calculated based on the molar amount of the substance, and the calculation formula is as follows: (1) Raw material conversion rate = (raw material added amount - raw material remaining amount) / raw material added amount * 100% (2) Product selectivity = molar amount of product / molar amount of all products.

[0026] Example 1: Add the dealuminated SBA-15 molecular sieve (the mass ratio of melamine to molecular sieve is 0.5) to 50 mL of melamine ethanol solution (concentration is 0.5M), stir at 80°C for 5h, remove the solvent by rotary evaporation, dry in an oven at 80°C for 12h, and heat the obtained product in nitrogen at a heating rate of 10°C / min, and keep it at 600°C for 4h to obtain Me-SBA-15, where Me indicates that the nitrogen-doped structure of the SBA-15 molecular sieve is derived from melamine. Add Me-SBA-15 (the mass ratio of cobalt acetate to Me-SBA-15 is 0.2) to 50 mL of cobalt acetate ethanol solution (concentration is 0.1M), fully sonicate, then stir at 60°C for 5h, remove the solvent by rotary evaporation, and dry in an oven at 80°C for 12h. Heat the obtained product in air at a heating rate of 20°C / min, and keep it at 500°C for 6h to obtain Co x O y / Me-SBA-15-WI catalyst (Co: 5.3wt%), WI indicates that the transition metal salt is introduced into the molecular sieve structure by impregnation method.

[0027] Co x O y / Me-SBA-15-WI catalyst, 0.015mol5-hydroxymethylfurfural, 0.06molNaHCO 3 and 20 mL of deionized water were added to a stainless steel autoclave with a polytetrafluoroethylene liner, wherein the metal: 5-hydroxymethylfurfural = 0.15:1 (mol:mol). The temperature was raised to 100 °C by an automatic temperature controller, and 1.0 MPa of oxygen was added for 10 hours. The pressure was kept constant during the reaction. The reaction product was acidified and analyzed by HPLC to obtain the reactant conversion rate and product selectivity. The catalyst was recovered and used again for the catalytic oxidation of 5-hydroxymethylfurfural, and was reused 4 times. After the reaction, HPLC was used for analysis. The reaction results are shown in Table 1.

[0028] Example 2: Add dealuminated SBA-15 molecular sieve (mass ratio of dicyandiamide to molecular sieve is 0.5) to 50mL ethanol solution of dicyandiamide (concentration is 0.5M), stir at 80°C for 5h, remove solvent by rotary evaporation, dry in oven at 80°C for 12h, heat the obtained product in nitrogen at a heating rate of 10°C / min, keep at 600°C for 4h, and obtain DCD-SBA-15, where DCD indicates that the nitrogen-doped structure of SBA-15 molecular sieve is derived from dicyandiamide. Add DCD-SBA-15 (mass ratio of cobalt acetate to DCD-SBA-15 is 0.2) to 50mL ethanol solution of cobalt acetate (concentration is 0.1M), sonicate thoroughly, then stir at 60°C for 5h, remove solvent by rotary evaporation, and dry in oven at 80°C for 12h, heat the obtained product in air at a heating rate of 20°C / min, and keep at 500°C for 6h, and obtain Co x O y / DCD-SBA-15-WI catalyst (Co: 4.8wt%), WI indicates that the transition metal salt is introduced into the molecular sieve structure by impregnation method.

[0029] Co x O y / DCD-SBA-15-WI catalyst, 0.015mol5-hydroxymethylfurfural, 0.06molNaHCO 3 and 20 mL of deionized water were added to a stainless steel autoclave with a polytetrafluoroethylene liner, wherein the metal: 5-hydroxymethylfurfural = 0.15:1 (mol:mol). The temperature was raised to 100 °C by an automatic temperature controller, and 1.0 MPa of oxygen was added for 10 hours. The pressure was kept constant during the reaction. The reaction product was acidified and analyzed by HPLC to obtain the reactant conversion rate and product selectivity. The catalyst was recovered and used again for the catalytic oxidation of 5-hydroxymethylfurfural. It was reused 4 times and analyzed by HPLC after the reaction. The reaction results are shown in Table 1.

[0030] Example 3: Add dealuminated ZSM-5 molecular sieve (mass ratio of dicyandiamide to molecular sieve is 0.5) to 50mL ethanol solution of dicyandiamide (concentration is 0.5M), stir at 80°C for 5h, remove solvent by rotary evaporation, dry in an oven at 80°C for 12h, and heat the obtained product in nitrogen at a heating rate of 10°C / min, and keep it at 600°C for 4h to obtain DCD-ZSM-5, where DCD indicates that the nitrogen-doped structure of ZSM-5 molecular sieve is derived from dicyandiamide. Add DCD-ZSM-5 (mass ratio of cobalt acetate to DCD-ZSM-5 is 0.2) to 50mL ethanol solution of cobalt acetate (concentration is 0.1M), fully ultrasonicate, then stir at 60°C for 5h, remove solvent by rotary evaporation, and dry in an oven at 80°C for 12h, and heat the obtained product in air at a heating rate of 20°C / min, and keep it at 500°C for 6h to obtain Co x O y / DCD-ZSM-5-WI catalyst (Co: 5.2wt%), WI indicates that the transition metal salt is introduced into the molecular sieve structure by impregnation method.

[0031] Co x O y / DCD-ZSM-5-WI catalyst, 0.015mol5-hydroxymethylfurfural, 0.06molNaHCO 3 and 20 mL of deionized water were added to a stainless steel autoclave with a polytetrafluoroethylene liner, wherein the metal: 5-hydroxymethylfurfural = 0.15:1 (mol:mol). The temperature was raised to 100 °C by an automatic temperature controller, and 1.0 MPa of oxygen was added for 10 hours. The pressure was kept constant during the reaction. The reaction product was acidified and analyzed by HPLC to obtain the reactant conversion rate and product selectivity. The catalyst was recovered and used again for the catalytic oxidation of 5-hydroxymethylfurfural. It was reused 4 times and analyzed by HPLC after the reaction. The reaction results are shown in Table 1.

[0032] Example 4: Add the dealuminated HY molecular sieve (the mass ratio of dicyandiamide to molecular sieve is 0.5) to 50 mL of ethanol solution of dicyandiamide (concentration is 0.5M), stir at 80°C for 5h, remove the solvent by rotary evaporation, and dry in an oven at 80°C for 12h. The obtained product is heated in nitrogen at a heating rate of 10°C / min and maintained at 600°C for 4h to obtain DCD-HY, where DCD indicates that the nitrogen-doped structure of the HY molecular sieve is derived from dicyandiamide. Add DCD-HY (the mass ratio of cobalt acetate to DCD-HY is 0.2) to 50 mL of ethanol solution of cobalt acetate (concentration is 0.1M), fully sonicate, then stir at 60°C for 5h, remove the solvent by rotary evaporation, and dry in an oven at 80°C for 12h. The obtained product is heated in air at a heating rate of 20°C / min and maintained at 500°C for 6h to obtain Cox O y / DCD-HY-WI catalyst (Co: 4.9wt%), WI indicates that the transition metal salt is introduced into the molecular sieve structure by impregnation method.

[0033] Co x O y / DCD-HY-WI catalyst, 0.015mol5-hydroxymethylfurfural, 0.06molNaHCO 3 and 20 mL of deionized water were added to a stainless steel autoclave with a polytetrafluoroethylene liner, wherein the metal: 5-hydroxymethylfurfural = 0.15:1 (mol:mol). The temperature was raised to 100 °C by an automatic temperature controller, and 1.0 MPa of oxygen was added for 10 hours. The pressure was kept constant during the reaction. The reaction product was acidified and analyzed by HPLC to obtain the reactant conversion rate and product selectivity. The catalyst was recovered and used again for the catalytic oxidation of 5-hydroxymethylfurfural. It was reused 4 times and analyzed by HPLC after the reaction. The reaction results are shown in Table 1.

[0034] Example 5: Add the dealuminated SBA-15 molecular sieve (the mass ratio of dicyandiamide to molecular sieve is 0.5) to 50 mL of ethanol solution of dicyandiamide (concentration is 0.5M), stir at 80°C for 5h, remove the solvent by rotary evaporation, and dry in an oven at 80°C for 12h. The obtained product is heated in nitrogen at a heating rate of 10°C / min and maintained at 600°C for 4h to obtain DCD-SBA-15. DCD indicates that the nitrogen-doped structure of SBA-15 molecular sieve is derived from dicyandiamide. Add DCD-SBA-15 (the mass ratio of manganese acetate to DCD-SBA-15 is 0.2) to 50 mL of ethanol solution of manganese acetate (concentration is 0.1M), fully sonicate, then stir at 60°C for 5h, remove the solvent by rotary evaporation, and dry in an oven at 80°C for 12h. The obtained product is heated in air at a heating rate of 20°C / min and maintained at 500°C for 6h to obtain Mn x O y / DCD-SBA-15-WI catalyst (Mn: 5.5wt%), WI means that the transition metal salt is introduced into the molecular sieve structure by impregnation method.

[0035] Mn x O y / DCD-SBA-15-WI catalyst, 0.015mol5-hydroxymethylfurfural, 0.06molNaHCO 3and 20mL of deionized water were added to a stainless steel autoclave with a polytetrafluoroethylene liner, wherein the metal: 5-hydroxymethylfurfural = 0.15:1 (mol:mol). The temperature was raised to 100°C by an automatic temperature controller, and 1.0MPa of oxygen was added for 10 hours. The pressure was kept constant during the reaction. The reaction product was acidified and analyzed by HPLC to obtain the reactant conversion rate and product selectivity. The catalyst was recovered and used again for the catalytic oxidation of 5-hydroxymethylfurfural, and was reused 4 times. After the reaction, HPLC was used to analyze the reaction results. The catalyst was recovered and used again for the catalytic oxidation of 5-hydroxymethylfurfural, and was reused 4 times. After the reaction, HPLC was used to analyze the reaction results. The results are shown in Table 1.

[0036] Example 6: Add dealuminated SBA-15 molecular sieve (mass ratio of dicyandiamide to molecular sieve is 0.5) to 50 mL of ethanol solution of dicyandiamide (concentration is 0.5M), stir at 80°C for 5h, remove solvent by rotary evaporation, dry in oven at 80°C for 12h, heat the obtained product in nitrogen at a heating rate of 10°C / min, and keep at 600°C for 4h to obtain DCD-SBA-15, where DCD indicates that the nitrogen-doped structure of SBA-15 molecular sieve is derived from dicyandiamide. Add DCD-SBA-15 (mass ratio of copper acetate to DCD-SBA-15 is 0.2) to 50 mL of ethanol solution of copper acetate (concentration is 0.1M), sonicate thoroughly, then stir at 60°C for 5h, remove solvent by rotary evaporation, and dry in oven at 80°C for 12h, heat the obtained product in air at a heating rate of 20°C / min, and keep at 500°C for 6h to obtain Cu x O y / DCD-SBA-15-WI catalyst (Cu: 4.6wt%), WI indicates that the transition metal salt is introduced into the molecular sieve structure by impregnation method.

[0037] Cu x O y / DCD-SBA-15-WI catalyst, 0.015mol5-hydroxymethylfurfural, 0.06molNaHCO 3 and 20 mL of deionized water were added to a stainless steel autoclave with a polytetrafluoroethylene liner, wherein the metal: 5-hydroxymethylfurfural = 0.15:1 (mol:mol). The temperature was raised to 100 °C by an automatic temperature controller, and 1.0 MPa of oxygen was added for 10 hours. The pressure was kept constant during the reaction. The reaction product was acidified and analyzed by HPLC to obtain the reactant conversion rate and product selectivity. The catalyst was recovered and used again for the catalytic oxidation of 5-hydroxymethylfurfural. It was reused 4 times and analyzed by HPLC after the reaction. The reaction results are shown in Table 1.

[0038] Example 7: To 50 mL of an ethanol solution of dicyandiamide (concentration of 0.5 M), dealuminated SBA-15 molecular sieve (mass ratio of dicyandiamide to molecular sieve is 0.5) was added, the mixture was stirred at 80°C for 5 h, the solvent was removed by rotary evaporation, and the mixture was dried in an oven at 80°C for 12 h. The resulting product was heated in nitrogen at a heating rate of 10°C / min and maintained at 600°C for 4 h to obtain DCD-SBA-15, where DCD indicates that the nitrogen-doped structure of the SBA-15 molecular sieve is derived from dicyandiamide. DCD-SBA-15 (the mass ratio of cobalt acetate to DCD-SBA-15 is 0.1, and the mass ratio of copper acetate to DCD-SBA-15 is 0.1) was added to 50 mL of a mixed ethanol solution of cobalt acetate and copper acetate (the concentrations of cobalt acetate and copper acetate were both 0.05 M), and the mixture was fully sonicated, followed by stirring at 60 ° C for 5 h, and the solvent was removed by rotary evaporation, and the mixture was dried in an oven at 80 ° C for 12 h. The obtained product was heated in air at a heating rate of 20 ° C / min and maintained at 500 ° C for 6 h to obtain Co x Cu y O z / DCD-SBA-15-WI catalyst (Co: 3.1wt%, Cu: 2.1wt%), WI means that the transition metal salt is introduced into the molecular sieve structure by impregnation method.

[0039] Co x Cu y O z / DCD-SBA-15-WI catalyst, 0.015mol5-hydroxymethylfurfural, 0.06molNaHCO 3 and 20 mL of deionized water were added to a stainless steel autoclave with a polytetrafluoroethylene liner, wherein the metal: 5-hydroxymethylfurfural = 0.15:1 (mol:mol). The temperature was raised to 100 °C by an automatic temperature controller, and 1.0 MPa of oxygen was added for 10 hours. The pressure was kept constant during the reaction. The reaction product was acidified and analyzed by HPLC to obtain the reactant conversion rate and product selectivity. The catalyst was recovered and used again for the catalytic oxidation of 5-hydroxymethylfurfural. It was reused 4 times and analyzed by HPLC after the reaction. The reaction results are shown in Table 1.

[0040] Example 8: To 50 mL of an ethanol solution of dicyandiamide (concentration of 0.5 M), dealuminated SBA-15 molecular sieve (mass ratio of dicyandiamide to molecular sieve is 0.5) was added, the mixture was stirred at 80°C for 5 h, the solvent was removed by rotary evaporation, and the mixture was dried in an oven at 80°C for 12 h. The resulting product was heated in nitrogen at a heating rate of 10°C / min and maintained at 600°C for 4 h to obtain DCD-SBA-15, where DCD indicates that the nitrogen-doped structure of the SBA-15 molecular sieve is derived from dicyandiamide. DCD-SBA-15 (the mass ratio of cobalt acetate to DCD-SBA-15 is 0.1, and the mass ratio of manganese acetate to DCD-SBA-15 is 0.1) was added to 50 mL of a mixed ethanol solution of cobalt acetate and manganese acetate (the concentrations of cobalt acetate and manganese acetate were both 0.05 M), and the mixture was fully sonicated, followed by stirring at 60 ° C for 5 h, and the solvent was removed by rotary evaporation, and the mixture was dried in an oven at 80 ° C for 12 h. The obtained product was heated in air at a heating rate of 20 ° C / min and maintained at 500 ° C for 6 h to obtain Co x Mn y O z / DCD-SBA-15-WI catalyst (Co: 2.5wt%, Mn: 2.6wt%), WI means that the transition metal salt is introduced into the molecular sieve structure by impregnation method.

[0041] Co x Mn y O z / DCD-SBA-15-WI catalyst, 0.015mol5-hydroxymethylfurfural, 0.06molNaHCO 3 and 20 mL of deionized water were added to a stainless steel autoclave with a polytetrafluoroethylene liner, wherein the metal: 5-hydroxymethylfurfural = 0.15:1 (mol:mol). The temperature was raised to 100 °C by an automatic temperature controller, and 1.0 MPa of oxygen was added for 10 hours. The pressure was kept constant during the reaction. The reaction product was acidified and analyzed by HPLC to obtain the reactant conversion rate and product selectivity. The catalyst was recovered and used again for the catalytic oxidation of 5-hydroxymethylfurfural. It was reused 4 times and analyzed by HPLC after the reaction. The reaction results are shown in Table 1.

[0042] Example 9: Add the dealuminated TS-1 molecular sieve (the mass ratio of o-phenanthroline to molecular sieve is 0.75) to 50 mL of ethanol solution of o-phenanthroline (concentration is 1.0 M), stir at 60°C for 5 h, remove the solvent by rotary evaporation, dry in an oven at 80°C for 12 h, and heat the obtained product in nitrogen at a heating rate of 20°C / min, and keep it at 800°C for 2 h to obtain Phen-TS-1, where Phen indicates that the nitrogen-doped structure of TS-1 molecular sieve is derived from o-phenanthroline. Add Phen-TS-1 (the mass ratio of acetylacetonato vanadium to Phen-TS-1 is 0.2) to 50 mL of mixed ethanol solution of acetylacetonato vanadium (concentration of acetylacetonato vanadium is 0.05 M), sonicate thoroughly, then stir at 80°C for 5 h, remove the solvent by rotary evaporation, and dry in an oven at 80°C for 12 h. Heat the obtained product in air at a heating rate of 20°C / min, and keep it at 600°C for 5 h to obtain V x O y / Phen-TS-1-WI catalyst (V: 6.1wt%), WI indicates that the transition metal salt is introduced into the molecular sieve structure by impregnation method.

[0043] V x O y / Phen-TS-1-WI catalyst, 0.01mol5-hydroxymethylfurfural, 0.06molNaOH and 20mL deionized water were added to a three-necked flask, wherein metal:5-hydroxymethylfurfural=0.2:1 (mol:mol). The temperature was raised to 60°C by an automatic temperature controller, and oxygen was added to the reaction system at a rate of 40mL / min by bubbling method, and the reaction was continued for 12 hours. The reaction product was acidified and analyzed by HPLC to obtain the reactant conversion rate and product selectivity. The catalyst was recovered and used again for catalytic oxidation of 5-hydroxymethylfurfural, and was reused 4 times. After the reaction, HPLC was used for analysis. The reaction results are shown in Table 1.

[0044] Example 10: Add the dealuminated HY molecular sieve (the mass ratio of o-phenanthroline to molecular sieve is 0.75) to 50 mL of ethanol solution of o-phenanthroline (concentration is 1.0 M), stir at 60°C for 5 h, remove the solvent by rotary evaporation, dry in an oven at 80°C for 12 h, and heat the obtained product in nitrogen at a heating rate of 20°C / min, and keep it at 800°C for 2 h to obtain Phen-HY, where Phen indicates that the nitrogen-doped structure of the HY molecular sieve is derived from o-phenanthroline. Add Phen-HY (the mass ratio of acetylacetonatovanadium to Phen-HY is 0.2) to 50 mL of mixed ethanol solution of acetylacetonatovanadium (concentration of acetylacetonatovanadium is 0.05 M), fully ultrasonicate, then stir at 80°C for 5 h, remove the solvent by rotary evaporation, and dry in an oven at 80°C for 12 h. Heat the obtained product in air at a heating rate of 20°C / min, and keep it at 600°C for 5 h to obtain V x O y / Phen-HY-WI catalyst (V: 5.1wt%), WI indicates that the transition metal salt is introduced into the molecular sieve structure by impregnation method.

[0045] V x O y / Phen-HY-WI catalyst, 0.01mol5-hydroxymethylfurfural, 0.06molNaOH and 20mL deionized water were added to a three-necked flask, wherein metal:5-hydroxymethylfurfural=0.2:1 (mol:mol). The temperature was raised to 60°C by an automatic temperature controller, and oxygen was added to the reaction system at a rate of 40mL / min by bubbling method for 12 hours. The reaction product was acidified and analyzed by HPLC to obtain the reactant conversion rate and product selectivity. The catalyst was recovered and used again for catalytic oxidation of 5-hydroxymethylfurfural, and was reused 4 times. After the reaction, HPLC was used for analysis. The reaction results are shown in Table 1.

[0046] Example 11: 50 mL of 3 N 4 The dealuminated ZSM-5 molecular sieve (C 3 N 4 The mass ratio of the molecular sieve to the molecular sieve is 0.5), stirred at 60°C for 10h, the solvent was removed by rotary evaporation, and the product was dried in an oven at 80°C for 12h. The product was heated at a heating rate of 10°C / min in nitrogen and maintained at 700°C for 2h to obtain C 3 N 4 -ZSM-5, C 3 N 4 It indicates that the nitrogen-doped structure of ZSM-5 molecular sieve comes from C 3 N 4 . Cobalt acetate, manganese acetate and C 3 N4 -ZSM-5 mixed (cobalt acetate and C 3 N 4 -ZSM-5 mass ratio is 0.16, manganese acetate and C 3 N 4 -ZSM-5 mass ratio is 0.04), followed by ball milling at 400 rpm for 6 h in a ball mill, and the obtained product was heated at a heating rate of 20 °C / min in air and maintained at 500 °C for 6 h to obtain Co x Mn y O z / C 3 N 4 -ZSM-5-BM catalyst (Co: 3.9wt%, Mn: 0.7wt%), BM indicates that the transition metal salt was introduced into the molecular sieve structure by ball milling.

[0047] Co x Mn y O z / C 3 N 4 -ZSM-5-BM catalyst, 0.015mol5-hydroxymethylfurfural, 0.03molNa 2 CO 3 and 20 mL of deionized water were added to a stainless steel autoclave with a polytetrafluoroethylene liner, wherein metal: 5-hydroxymethylfurfural = 0.15:1 (mol:mol). The temperature was raised to 120°C by an automatic temperature controller, and 1.0 MPa of oxygen was added for 5 hours. The pressure was kept constant during the reaction. The reaction product was acidified and analyzed by HPLC to obtain the reactant conversion rate and product selectivity. The catalyst was recovered and used again for the catalytic oxidation of 5-hydroxymethylfurfural. It was reused 4 times and analyzed by HPLC after the reaction. The reaction results are shown in Table 1.

[0048] Example 12: 50 mL of 3 N 4 The dealuminated ZSM-5 molecular sieve (C 3 N 4 The mass ratio of the molecular sieve to the molecular sieve is 0.5), stirred at 60°C for 10h, the solvent was removed by rotary evaporation, and the product was dried in an oven at 80°C for 12h. The product was heated at a heating rate of 10°C / min in nitrogen and maintained at 700°C for 2h to obtain C 3 N 4 -ZSM-5, C 3 N 4 It indicates that the nitrogen-doped structure of ZSM-5 molecular sieve comes from C 3 N 4 . Cobalt acetate, copper acetate and C3 N 4 -ZSM-5 mixed (cobalt acetate and C 3 N 4 The mass ratio of copper acetate to C 3 N 4 -ZSM-5 mass ratio is 0.04), followed by ball milling at 400 rpm for 6 h in a ball mill, and the obtained product was heated in air at a heating rate of 20 °C / min and maintained at 500 °C for 6 h to obtain Co x Cu y O z / C 3 N 4 -ZSM-5-BM catalyst (Co: 4.4wt%, Cu: 1.2wt%), BM indicates that the transition metal salt was introduced into the molecular sieve structure by ball milling.

[0049] Co x Cu y O z / C 3 N 4 -ZSM-5-BM catalyst, 0.015mol5-hydroxymethylfurfural, 0.03molNa 2 CO 3 and 20 mL of deionized water were added to a stainless steel autoclave with a polytetrafluoroethylene liner, wherein metal: 5-hydroxymethylfurfural = 0.15:1 (mol:mol). The temperature was raised to 120°C by an automatic temperature controller, and 1.0 MPa of oxygen was added for 5 hours. The pressure was kept constant during the reaction. The reaction product was acidified and analyzed by HPLC to obtain the reactant conversion rate and product selectivity. The catalyst was recovered and used again for the catalytic oxidation of 5-hydroxymethylfurfural. It was reused 4 times and analyzed by HPLC after the reaction. The reaction results are shown in Table 1.

[0050] Example 13: To 50 mL of 2,2'-bipyridine ethanol solution (concentration 0.5 M), add dealuminated KIT-6 molecular sieve (the mass ratio of 2,2'-bipyridine to molecular sieve is 0.75), stir at 80°C for 5 h, remove the solvent by rotary evaporation, and dry in an oven at 80°C for 12 h. The resulting product is heated in nitrogen at a heating rate of 20°C / min and maintained at 500°C for 4 h to obtain Bpy-KIT-6, where Bpy indicates that the nitrogen-doped structure of the KIT-6 molecular sieve is derived from 2,2'-bipyridine. Bpy-KIT-6 (the mass ratio of manganese nitrate to Bpy-KIT-6 is 0.4) was added to 50 mL of ethanol solution of manganese nitrate (concentration of 0.1 M), and then the mixture was fully sonicated and stirred at 80 ° C for 5 h. The solvent was removed by rotary evaporation and dried in an oven at 80 ° C for 12 h. The obtained product was heated in air at a heating rate of 20 ° C / min and maintained at 500 ° C for 6 h to obtain Mn x O y / Bpy-KIT-6-WI catalyst (Mn: 7.8wt%), WI means that the transition metal salt is introduced into the molecular sieve structure by impregnation method.

[0051] Mn x O y / Bpy-KIT-6-WI catalyst, 0.015mol5-hydroxymethylfurfural, 0.06molNaHCO 3 and 20 mL of deionized water were added to a stainless steel autoclave with a polytetrafluoroethylene liner, wherein metal: 5-hydroxymethylfurfural = 0.15:1 (mol:mol). The temperature was raised to 120 °C by an automatic temperature controller, and 1.0 MPa of oxygen was added for 12 hours. The pressure was kept constant during the reaction. The reaction product was acidified and analyzed by HPLC to obtain the reactant conversion rate and product selectivity. The catalyst was recovered and used again for catalytic oxidation of 5-hydroxymethylfurfural, and was reused 4 times. After the reaction, HPLC was used for analysis. The reaction results are shown in Table 1.

[0052] Example 14: Add the dealuminated KIT-6 molecular sieve (the mass ratio of 2,2'-bipyridine to molecular sieve is 0.75) to 50 mL of 2,2'-bipyridine ethanol solution (concentration is 0.5M), stir at 80°C for 5 hours, remove the solvent by rotary evaporation, and dry in an oven at 80°C for 12 hours. The obtained product is heated in nitrogen at a heating rate of 20°C / min and maintained at 500°C for 4 hours to obtain Bpy-KIT-6, where Bpy indicates that the nitrogen-doped structure of KIT-6 molecular sieve is derived from 2,2'-bipyridine. Manganese nitrate is mixed with Bpy-KIT-6 (the mass ratio of manganese nitrate to Bpy-KIT-6 is 0.4), and then ball-milled in a ball mill at a speed of 400 rpm for 6 hours. The obtained product is heated in air at a heating rate of 20°C / min and maintained at 500°C for 6 hours to obtain Mn x O y / Bpy-KIT-6-BM catalyst (Mn: 8.3wt%), BM indicates that the transition metal salt is introduced into the molecular sieve structure by ball milling.

[0053] Mn x O y / Bpy-KIT-6-BM catalyst, 0.015mol5-hydroxymethylfurfural, 0.06molNaHCO 3 and 20 mL of deionized water were added to a stainless steel autoclave with a polytetrafluoroethylene liner, wherein metal: 5-hydroxymethylfurfural = 0.15:1 (mol:mol). The temperature was raised to 120 °C by an automatic temperature controller, and 1.0 MPa of oxygen was added for 12 hours. The pressure was kept constant during the reaction. The reaction product was acidified and analyzed by HPLC to obtain the reactant conversion rate and product selectivity. The catalyst was recovered and used again for catalytic oxidation of 5-hydroxymethylfurfural, and was reused 4 times. After the reaction, HPLC was used for analysis. The reaction results are shown in Table 1.

[0054] Table 1 Catalytic oxidation results of 5-hydroxymethylfurfural on different catalysts

[0055]

[0056] HMF: 5-hydroxymethylfurfural; FFCA: 5-formyl-2-furancarboxylic acid; FDCA: 2,5-furandicarboxylic acid.

Claims

1. A catalyst for catalytic synthesis of 2,5-furandicarboxylic acid, characterized in that: The catalyst is a molecular sieve-coated transition metal oxide catalyst, the active component of the catalyst is a transition metal oxide, selected from at least one of iron oxide, cobalt oxide, copper oxide, manganese oxide or vanadium oxide; the source of the active component is selected from at least one of nitrates, sulfates, acetates and acetylacetonates of transition metals of iron, cobalt, copper, manganese and vanadium; The catalyst carrier is a nitrogen species-modified molecular sieve, and the molecular sieve is selected from at least one of SBA-15, TS-1, ZSM-5, MCM-41, KIT-6, Beta or HY molecular sieves; The nitrogen species in the catalyst support structure is derived from nitrogen-containing organic matter, and the nitrogen-containing organic matter is selected from at least one of 2,2'-bipyridine, 2,2'-bipyridineamine, terpyridine, o-phenanthroline, dicyandiamide, melamine, urea, triethylamine, ethylenediamine, diethylenetriamine, acrylamide, lysine, histidine or C3N4.

2. A method for preparing a catalyst for catalytic synthesis of 2,5-furandicarboxylic acid according to claim 1, characterized in that: The preparation method of the nitrogen species modified molecular sieve comprises: adding the molecular sieve into an ethanol solution containing nitrogen-containing organic matter, performing an impregnation reaction, then removing the solvent, and thermally decomposing in an inert atmosphere to obtain the nitrogen species modified molecular sieve.

3. The method for preparing the catalyst for catalytic synthesis of 2,5-furandicarboxylic acid according to claim 2, characterized in that: The impregnation method of nitrogen-containing organic matter is heating and stirring impregnation, the temperature is 25-80°C, and the time is 0.5-10h; the concentration of nitrogen-containing organic matter is 0.2-2M, and the mass ratio of the nitrogen-containing species to the molecular sieve is 0.1-1; after impregnation, the pyrolysis temperature is 300-500°C, the heating rate is 5-10°C / min, and the pyrolysis time is 1-5h.

4. The method for preparing the catalyst for catalytic synthesis of 2,5-furandicarboxylic acid according to claim 2, characterized in that: The preparation method of the nitrogen-modified molecular sieve coated metal oxide catalyst is as follows: adding the nitrogen-modified molecular sieve to an ethanol solution containing a transition metal salt to carry out an impregnation reaction, then removing the solvent, and calcining in an air atmosphere to obtain the nitrogen-modified molecular sieve coated transition metal oxide catalyst; or mixing the nitrogen-modified molecular sieve with the transition metal salt by a solid grinding method, and then calcining in an air atmosphere to obtain the nitrogen-modified molecular sieve coated transition metal oxide catalyst.

5. The method for preparing the catalyst for catalytic synthesis of 2,5-furandicarboxylic acid according to claim 4, characterized in that: The impregnation method of the transition metal salt is heating and stirring impregnation, the stirring temperature is 25-60°C, and the stirring time is 2-10 hours; the concentration of the transition metal salt solution is 0.01-0.1M, and the mass ratio of the transition metal salt to the nitrogen-doped molecular sieve is 0.1-0.5; after impregnation, the calcination temperature is 400-800°C, the heating rate is 5-10°C / min, the calcination time is 1-5 hours, the calcination atmosphere is selected from at least one of nitrogen or argon, the nitrogen species modified molecular sieve and the transition metal salt are mixed by mechanical grinding in a ball mill, the rotation speed of the ball mill is 200-800 rpm, and the ball milling time is 2-10 hours.

6. The method for preparing the catalyst for catalytic synthesis of 2,5-furandicarboxylic acid according to claim 2, characterized in that: The loading amount of the metal component in the nitrogen-modified molecular sieve-coated metal oxide catalyst is 3.0 wt% to 30.0 wt%, and the content of the nitrogen species is 2.0 wt% to 20.0 wt%.

7. Use of the catalyst for catalytic synthesis of 2,5-furandicarboxylic acid according to claim 1, characterized in that: 5-Hydroxymethylfurfural is contacted with a catalyst in an oxygen-containing atmosphere to react and prepare 2,5-furandicarboxylic acid.

8. Use of the catalyst for catalytic synthesis of 2,5-furandicarboxylic acid according to claim 7, characterized in that: The method comprises the following steps: mixing the catalyst, 5-hydroxymethylfurfural, an alkaline additive and water, and reacting them in an oxygen-containing atmosphere; the reaction temperature is 50-120° C., the reaction time is 5-12 hours, and the reaction pressure is normal pressure to 2.0 MPa; after the reaction is completed, adding acid to obtain 2,5-furandicarboxylic acid.

9. Use of the catalyst for catalytic synthesis of 2,5-furandicarboxylic acid according to claim 8, characterized in that: The alkaline additive is selected from at least one of LiOH, Li2CO3, CH3COOLi, NaOH, Na2CO3, NaHCO3, CH3COONa, KOH, K2CO3, KHCO3, and CH3COOK; the molar ratio of the alkaline additive to 5-hydroxymethylfurfural is 1:1 to 4:1; and the molar ratio of the metal component in the catalyst to 5-hydroxymethylfurfural is 0.05:1 to 0.2:1.

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