A method for preparing a selective oxidation catalyst and its use in the synthesis of 2,5-diformylfuran

Abstract

The invention discloses a method for preparing a selective oxidation catalyst and its use in synthesizing 2,5-diformylfuran. The method for preparing the selective oxidation catalyst comprises: S1, impregnating a carbonaceous material with an aqueous solution containing nitrogen element, drying and then performing a first roasting in an inert gas to obtain a nitrogen-doped carbon carrier; S2, mixing the nitrogen-doped carbon carrier with an active metal component compound solution to obtain a first mixture; S3, performing a first drying and a first reduction on the first mixture. The selective oxidation catalyst can catalyze 2,5-diformylfuran with high selectivity, slowing down the process of the product continuing to undergo an oxidation reaction.

Description

Technical Field

[0001] The present application relates to the field of chemistry and chemical engineering, and in particular, to a method for preparing a catalyst and a method for selectively oxidizing 5-hydroxymethylfurfural to synthesize 2,5-diformylfuran. Background Art

[0002] With the consumption of fossil fuels and their impact on the environment, the search for sustainable alternative energy and chemicals has received widespread attention worldwide. Biomass resources are widely available, cheap, and abundant in reserves. More importantly, they have a high proportion of carbohydrates. 5-Hydroxymethylfurfural (HMF), an important biomass-based platform compound, can be produced by acid-catalyzed dehydration of carbohydrates such as fructose, glucose, and cellulose. HMF has hydroxymethyl and aldehyde functional groups and has active chemical properties. It can be used to synthesize a series of platform compounds such as 2,5-furandicarboxylic acid (FDCA) and 2,5-diformylfuran (DFF) through selective oxidation or hydrogenation reduction. DFF can be used to prepare pesticide intermediates, fungicides, and heterocyclic compounds. Achieving efficient oxidation of HMF to produce DFF will help open up the biomass utilization path from cellulose to HMF and then to chemical raw materials, laying an important foundation for replacing fossil resources in the future.

[0003] At present, HMF is selectively oxidized to prepare DFF, mainly using chemical oxidants such as manganese dioxide, chromium trioxide, sodium hypochlorite, etc. in stoichiometric amounts, but the environmental pollution is relatively serious, the reaction time is long, the amount of oxidant and reaction solvent is large, and the product yield is very low, which is not suitable for large-scale industrial production. In recent years, some researchers have used oxygen or air as an oxidant, such as the prior art CN109174153A, which uses 5-hydroxymethylfurfural as a raw material, oxygen or air as an oxidant, a CN material of nitrogen-doped carbon material as a catalyst, and acetic acid as a solvent, and can obtain up to 98% of the target product, but the reaction requires the addition of 65-68% concentrated nitric acid, which has safety and corrosion problems. In addition, the reactant concentration is less than 1%, which will involve the problem of large-scale wastewater and waste reagent treatment, which is not conducive to industrial scale-up application.

[0004] Therefore, there is an urgent need in the art to further improve catalyst activity and cycle stability to increase the conversion rate of 5-hydroxymethylfurfural and the selectivity of 2,5-diformylfuran. Summary of the invention

[0005] The purpose of the present disclosure is to provide an efficient and stable supported metal catalyst and to develop a mild, green and environmentally friendly reaction system to oxidize 5-hydroxymethylfurfural to prepare 2,5-diformylfuran with high selectivity.

[0006] In order to achieve the above object, the present disclosure provides a first aspect of a method for preparing a selective oxidation catalyst, the method comprising:

[0007] S1, impregnating the carbonaceous material with an aqueous solution containing nitrogen, drying it, and then performing a first calcination in an inert gas to obtain a nitrogen-doped carbon support;

[0008] S2, mixing the nitrogen-doped carbon support with an active metal component compound solution to obtain a first mixture;

[0009] S3, subjecting the first mixture to a first drying and a first reduction.

[0010] Optionally, the specific surface area of ​​the carbonaceous material is 200-2500m 2 / g, preferably 800-1800m 2 / g; the carbon-containing material is selected from at least one of activated carbon, carbon black, carbon nanotubes, graphene and graphene oxide, preferably activated carbon and / or carbon black; the aqueous solution containing nitrogen element is selected from ammonia solution and / or urea solution; the mass ratio of the carbon-containing material to the nitrogen element is 30:1-1:2, preferably 25:1-1:1.

[0011] Optionally, the active metal component compound is selected from soluble metal compounds of Group VIII metals; optionally, the soluble metal compound of Group VIII metals is at least one of nitrates, acetates, soluble carbonates, chlorides and soluble complexes of Group VIII metals; the Group VIII metal is selected from at least one of rhodium, palladium and ruthenium; preferably, the active metal component compound is a chloride of Group VIII metal; further preferably, the active metal component compound is ruthenium chloride.

[0012] Optionally, based on the mass of the catalyst, the mass fraction of the active metal component element is 1%-25%, preferably 5%-15%.

[0013] Optionally, in step S1, the impregnation conditions include: the impregnation temperature is 15-40°C, preferably 20-30°C; the impregnation time is 12-36 hours, preferably 18-24 hours; the first calcination conditions include: the calcination temperature is 1000-1500°C, preferably 1100-1300°C; the calcination time is 2-12 hours, preferably 4-8 hours;

[0014] In step S2, the mixing is isochoric impregnation mixing; the mixing conditions include: the mixing temperature is 15-40° C., preferably 20-30° C.; the mixing time is 12-36 hours, preferably 18-28 hours;

[0015] In step S3, the first drying conditions include: drying temperature of 60-140°C, preferably 90-120°C; drying time of 6-24 hours, preferably 10-18 hours; the first reduction conditions include: carried out in a reducing atmosphere containing hydrogen; preferably, the reducing atmosphere contains 10-100 volume % hydrogen and 0-90 volume % inert gas; reduction temperature of 200-800°C, preferably 350-650°C; reduction time of 2-6 hours, preferably 2.5-4.5 hours.

[0016] A second aspect of the present disclosure provides a selective oxidation catalyst, the selective oxidation catalyst comprising a nitrogen-doped carbon support and an active metal component; the specific surface area of ​​the nitrogen-doped carbon support is 200-2500 m 2 / g; in the nitrogen-doped carbon carrier, the mass fraction of nitrogen is 0.01-5% by weight, and the mass fraction of oxygen is 3-15% by weight; based on the weight of the selective oxidation catalyst, the content of the active metal component is 1-25% by weight.

[0017] Optionally, the N 1s In the spectrum, there is a characteristic peak between 399-400.5ev.

[0018] Optionally, the active metal component compound is selected from oxides of Group VIII metals; preferably, the oxide of Group VIII metals is an oxide of at least one of rhodium, palladium and ruthenium; further preferably, the oxide of Group VIII metals is an oxide of ruthenium.

[0019] The third aspect of the present disclosure provides a method for preparing 2,5-diformylfuran, the preparation method comprising:

[0020] SS1, dissolving 5-hydroxymethylfurfural in an organic solvent to obtain a mixed solution;

[0021] SS2, adding a selective oxidation catalyst to the mixed solution to carry out an oxidation reaction;

[0022] Wherein, the selective oxidation catalyst is the selective oxidation catalyst prepared by the above-mentioned preparation method or the above-mentioned selective oxidation catalyst.

[0023] Optionally, the mass ratio of the organic solvent to 5-hydroxymethylfurfural is 2-50:1, preferably 5-20:1; the molar ratio of 5-hydroxymethylfurfural to the active metal component in the selective oxidation catalyst is 80-450:1, preferably 100-320:1; optionally, the organic solvent is selected from one or more of toluene, dioxane, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethyl sulfoxide, tetrahydrofuran, pyridine and acetonitrile.

[0024] Optionally, in step SS2, the conditions of the oxidation reaction include: oxygen partial pressure of 0.05MPa-2MPa, preferably 0.5MPa-1MPa; reaction temperature of 50°C-200°C, preferably 80°C-120°C; reaction time of 0.5h-10h, preferably 1h-4h.

[0025] Through the above technical solution, the present disclosure has the following beneficial effects:

[0026] (1) The present disclosure, by nitrogen doping the carbonaceous material, can obtain a noble metal catalyst with a high loading, maintain the utilization rate of the active metal, improve the activity of the catalyst, and appropriately reduce the amount of the catalyst, thereby saving costs; on the other hand, by modifying the carrier, it is beneficial to desorb the product from the catalyst surface, avoiding further oxidation of the product to generate other by-products. Therefore, the use of the catalyst can promote the catalytic conversion of high-concentration reactants to obtain highly selective target products.

[0027] (2) The reaction solvents used in the present invention are all conventional organic solvents, which are cheap and easily available, and air or oxygen is used as the oxygen source, avoiding the use of organic oxidants such as nitrates, thereby simplifying the post-processing steps of the product and avoiding the problem of acid-containing wastewater discharge, thereby reducing energy consumption, being green and environmentally friendly, and having broad industrial application prospects.

[0028] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0030] Figure 1 is the XPS spectrum of the nitrogen-doped carbon support of Example 1;

[0031] Figure 2 is the XPS spectrum of the nitrogen-doped carbon support of Example 2;

[0032] Figure 3is the XPS spectrum of the nitrogen-doped carbon support of Example 3. DETAILED DESCRIPTION

[0033] The specific embodiments of the present disclosure are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure, and are not used to limit the present disclosure.

[0034] A first aspect of the present disclosure provides a method for preparing a selective oxidation catalyst, the method comprising:

[0035] S1, impregnating the carbonaceous material with an aqueous solution containing nitrogen, drying it, and then performing a first calcination in an inert gas to obtain a nitrogen-doped carbon support;

[0036] S2, mixing the nitrogen-doped carbon support with an active metal component compound solution to obtain a first mixture;

[0037] S3, subjecting the first mixture to a first drying and a first reduction.

[0038] The present invention provides a method for nitrogen doping modification of carbonaceous materials, which uses nitrogen-doped carbon materials as carriers to prepare catalysts loaded with precious active metal components, and can catalyze the production of 2,5-diformylfuran with high selectivity, slowing down the process of the product's continued oxidation reaction.

[0039] According to the first aspect of the present disclosure, the specific surface area of ​​the carbonaceous material may be 200-2500m 2 / g, preferably 800-1800m 2 / g; the carbon-containing material can be selected from at least one of activated carbon, carbon black, carbon nanotubes, graphene and graphene oxide, preferably activated carbon and / or carbon black; the aqueous solution containing nitrogen element can be selected from ammonia solution and / or urea solution; the mass ratio of the carbon-containing material to the nitrogen element can be 30:1-1:2, preferably 25:1-1:1.

[0040] According to the first aspect of the present disclosure, the XPS analysis of the nitrogen-doped carbon support is 1s The spectrum has characteristic peaks between 399ev-400.5ev.

[0041] According to the first aspect of the present disclosure, the active metal component compound can be selected from soluble metal compounds of Group VIII metals; optionally, the soluble metal compound of Group VIII metals is at least one of nitrates, acetates, soluble carbonates, chlorides and soluble complexes of Group VIII metals; the Group VIII metal can be selected from at least one of rhodium, palladium and ruthenium; preferably, the active metal component compound is a chloride of Group VIII metal; further preferably, the active metal component compound is ruthenium chloride.

[0042] According to the first aspect of the present disclosure, based on the mass of the catalyst, the mass fraction of the active metal component element may be 1%-25%, preferably 5%-15%.

[0043] According to the first aspect of the present disclosure, in step S1, the impregnation conditions may include: an impregnation temperature of 15-40°C, preferably 20-30°C; an impregnation time of 12-36 hours, preferably 18-24 hours; the first calcination conditions may include: a calcination temperature of 1000-1500°C, preferably 1100-1300°C; a calcination time of 2-12 hours, preferably 4-8 hours;

[0044] In step S2, the mixing may be isochoric impregnation mixing; the mixing conditions may include: a mixing temperature of 15-40° C., preferably 20-30° C.; a mixing time of 12-36 hours, preferably 18-28 hours;

[0045] In step S3, the first drying conditions may include: a drying temperature of 1000-1500°C, preferably 90-120°C; a drying time of 0.2-12 hours, preferably 10-18 hours; the first reduction conditions may include: carried out in a reducing atmosphere containing hydrogen; preferably, the reducing atmosphere contains 10-100 volume % hydrogen and 0-90 volume % inert gas; the reduction temperature is 200-800°C, preferably 350-650°C; the reduction time is 2-6 hours, preferably 2.5-4.5 hours.

[0046] A second aspect of the present disclosure provides a selective oxidation catalyst, the selective oxidation catalyst comprising a nitrogen-doped carbon support and an active metal component; the specific surface area of ​​the nitrogen-doped carbon support is 200-2500 m 2 / g; in the nitrogen-doped carbon carrier, the mass fraction of nitrogen is 0.01-5% by weight, and the mass fraction of oxygen is 3-15% by weight; based on the weight of the selective oxidation catalyst, the content of the active metal component is 1-25% by weight.

[0047] According to the second aspect of the present disclosure, the N of the nitrogen-doped carbon support analyzed by XPS is 1s In the spectrum, there is a characteristic peak between 399-400.5ev.

[0048] According to the second aspect of the present disclosure, the active metal component compound can be selected from oxides of Group VIII metals; preferably, the oxide of Group VIII metals is an oxide of at least one of rhodium, palladium and ruthenium; further preferably, the oxide of Group VIII metals is an oxide of ruthenium.

[0049] The third aspect of the present disclosure provides a method for preparing 2,5-diformylfuran, the preparation method comprising:

[0050] SS1, dissolving 5-hydroxymethylfurfural in an organic solvent to obtain a mixed solution;

[0051] SS2, adding a selective oxidation catalyst to the mixed solution to carry out an oxidation reaction;

[0052] Wherein, the selective oxidation catalyst is the selective oxidation catalyst prepared by the above-mentioned preparation method or the above-mentioned selective oxidation catalyst.

[0053] The preparation method of 2,5-diformylfuran disclosed in the present invention can increase the single-pass processing amount of 5-hydroxymethylfurfural, and ensure that a highly selective target product is obtained under the condition of high reactant concentration.

[0054] According to the third aspect of the present disclosure, the mass ratio of the organic solvent to 5-hydroxymethylfurfural can be 2-50:1, preferably 5-20:1; the molar ratio of 5-hydroxymethylfurfural to the active metal component in the selective oxidation catalyst is 80-450:1, preferably 100-320:1; optionally, the organic solvent is selected from one or more of toluene, dioxane, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethyl sulfoxide, tetrahydrofuran, pyridine and acetonitrile.

[0055] According to the third aspect of the present disclosure, in step SS2, the oxidation reaction can be carried out under an oxygen atmosphere or an air atmosphere, and the conditions of the oxidation reaction may include: an oxygen partial pressure of 0.05MPa-2MPa, preferably 0.5MPa-1MPa; a reaction temperature of 50°C-200°C, preferably 80°C-120°C; and a reaction time of 0.5h-10h, preferably 1h-4h.

[0056] The present disclosure is further described in detail by examples. The raw materials used in the examples can be obtained through commercial sources. Among them, the activated carbon is coconut shell charcoal, and the manufacturers include Beijing Dalihongye Technology Co., Ltd. and Calgon Carbon (Suzhou) Co., Ltd. (brand 107C); carbon black includes EC-300J, EC-600JD, ECP-600JD, VXC72, and Blackpearls 2000.

[0057] Example 1

[0058] This example is used to illustrate the preparation of the nitrogen-doped carbon material disclosed in the present invention.

[0059] 1 g of Calgon Carbon 107C activated carbon was immersed in 15 mL of 0.7 wt% urea aqueous solution for 24 h; dried in an oven at 100°C; then placed in a tubular furnace, heated to 1200°C at a rate of 10°C / min in an argon atmosphere, and kept at a constant temperature for 3 h; after natural cooling, a nitrogen-doped carbon carrier was obtained, which was numbered as carbon carrier A.

[0060] The nitrogen mass fraction of XPS analysis is 0.68%; the oxygen mass fraction of XPS analysis is 8.92%; the specific surface area is 1230m 2 / g. Figure 1 This is the XPS spectrum of the nitrogen-doped carbon support of Example 1.

[0061] Example 2

[0062] This example is used to illustrate the preparation of the nitrogen-doped carbon material disclosed in the present invention.

[0063] 10 mL of anhydrous ethanol was added to 1 g of Ketjenblack ECP600JD, and then 25 mL of 10 wt% ammonia solution was added and immersed for 24 h; the mixture was dried in an oven at 100 °C; the mixture was then placed in a tubular furnace, and the temperature was raised to 1100 °C at a rate of 8 °C / min in an argon atmosphere, and the mixture was kept at a constant temperature for 3 h; after natural cooling, a nitrogen-doped carbon carrier was obtained, which was numbered as carbon carrier B.

[0064] The nitrogen mass fraction of XPS analysis is 1.48%; the oxygen mass fraction of XPS analysis is 11.22%; the specific surface area is 1378m 2 / g. Figure 2 This is the XPS spectrum of the nitrogen-doped carbon support of Example 2.

[0065] Example 3

[0066] This example is used to illustrate the preparation of the nitrogen-doped carbon material disclosed in the present invention.

[0067] To 1g of Black pearls 2000, 10mL of anhydrous ethanol was added, and then 20mL of a 1wt% urea aqueous solution was added and immersed for 24h; the mixture was dried in an oven at 100°C; the mixture was then placed in a tubular furnace, and the temperature was raised to 1300°C at a rate of 10°C / min in an argon atmosphere, and the mixture was kept at a constant temperature for 3h; after natural cooling, a nitrogen-doped carbon carrier was obtained, which was numbered as carbon carrier C.

[0068] The nitrogen mass fraction of XPS analysis is 1.31%; the oxygen mass fraction of XPS analysis is 9.54%; the specific surface area is 1385m 2 / g. Figure 3 This is the XPS spectrum of the nitrogen-doped carbon support of Example 3.

[0069] Example 4

[0070] This example is used to illustrate the preparation of the ruthenium-carbon catalyst disclosed in the present invention.

[0071] The RuCl 3 The aqueous solution and carbon support A were stirred and impregnated at room temperature for 8 h, wherein RuCl 3 The mass ratio of metal Ru to carrier A in the aqueous solution was 0.12:1, and a first mixture was obtained. The first mixture was then dried at 120° C. for 12 h to obtain a catalyst precursor. The catalyst precursor was placed in a tube furnace at 20% by volume H 2 / 80 volume%N 2 The catalyst was reduced at 600°C in an atmosphere for 3 hours to obtain a ruthenium-carbon selective oxidation catalyst having an active component content of 11.8 wt%.

[0072] Example 5

[0073] This example is used to illustrate the preparation of the ruthenium carbon selective oxidation catalyst disclosed in the present invention.

[0074] A ruthenium carbon selective oxidation catalyst was prepared according to the method of Example 4, except that the carbon support B prepared in Example 2 was used, and RuCl 3 The mass ratio of metal Ru to carrier B in the aqueous solution is 0.2:1, and a ruthenium-carbon selective oxidation catalyst with an active component content of 19.6 wt % is obtained.

[0075] Example 6

[0076] This example is used to illustrate the preparation of the ruthenium carbon selective oxidation catalyst disclosed in the present invention.

[0077] A ruthenium carbon selective oxidation catalyst was prepared according to the method of Example 4, except that the carbon support C prepared in Example 2 was used, and RuCl 3The mass ratio of metal Ru to carrier C in the aqueous solution is 0.03:1, and a ruthenium-carbon selective oxidation catalyst with an active component content of 2.9 wt % is obtained.

[0078] Example 7

[0079] This example is used to illustrate the preparation of the palladium-carbon selective oxidation catalyst disclosed in the present invention.

[0080] The palladium-carbon selective oxidation catalyst was prepared according to the method of Example 4, except that PdCl 2 The carbon support A was impregnated with the aqueous solution to obtain a palladium-carbon selective oxidation catalyst having an active component content of 11.8 wt %.

[0081] Example 8

[0082] This example is used to illustrate the preparation of the rhodium-carbon selective oxidation catalyst disclosed in the present invention.

[0083] The rhodium-carbon selective oxidation catalyst was prepared according to the method of Example 4, except that RhCl 3 The carbon support A was impregnated with the aqueous solution to obtain a rhodium-carbon selective oxidation catalyst having an active component content of 11.8 wt%.

[0084] Example 9

[0085] This example is used to illustrate the method for preparing 2,5-diformylfuran disclosed in the present invention.

[0086] 1.0g 5-hydroxymethylfurfural was added to a 50mL stainless steel autoclave, 10g solvent toluene was added to obtain a mixed solution, and 0.027g of the ruthenium carbon selective oxidation catalyst obtained in Example 4 was added to the mixed solution, oxygen was charged to 1.2MPa, the reactor was sealed, and the reaction temperature was raised to 110°C by automatic temperature control program heating, and kept at this temperature for 2h under continuous stirring, and the pressure was kept constant during the reaction. After the reaction was completed, it was cooled to room temperature. The reaction solution was collected after filtering and washing. The reaction solution was diluted with deionized water, fixed to 100mL, and sampled for high performance liquid chromatography analysis. The catalytic reaction results are listed in Table 1.

[0087] Example 10

[0088] 2,5-diformylfuran was prepared according to the method of Example 9, except that the catalyst was the ruthenium carbon selective oxidation catalyst of Example 5, and the amount of catalyst added was 0.016 g. The catalytic reaction results are listed in Table 1.

[0089] Embodiment 11

[0090] 2,5-diformylfuran was prepared according to the method of Example 9, except that the catalyst was the ruthenium carbon selective oxidation catalyst of Example 6, and the amount of catalyst added was 0.111 g. The catalytic reaction results are listed in Table 1.

[0091] Example 12

[0092] 2,5-diformylfuran was prepared according to the method of Example 9, except that the palladium-carbon selective oxidation catalyst of Example 7 was used as the catalyst, and the amount of the catalyst added was 0.029 g. The catalytic reaction results are listed in Table 1.

[0093] Embodiment 13

[0094] 2,5-diformylfuran was prepared according to the method of Example 9, except that the catalyst was the rhodium-carbon selective oxidation catalyst of Example 8, and the amount of catalyst added was 0.028 g. The catalytic reaction results are listed in Table 1.

[0095] Embodiment 14

[0096] 2,5-diformylfuran was prepared according to the method of Example 9, except that the mass of the reactant 5-hydroxymethylfurfural was 0.1 g and the reaction time was 1 h. The catalytic reaction results are listed in Table 1.

[0097] Comparative Example 1

[0098] The ruthenium-on-carbon catalyst was prepared according to the method of Example 4, except that the carrier was Calgon Carbon Activated Carbon 107C which was not doped. Using the catalyst, 2,5-diformylfuran was prepared according to the method of Example 9. The catalytic reaction results are listed in Table 1.

[0099] Comparative Example 2

[0100] The ruthenium carbon catalyst was prepared according to the method of Example 4, except that the carrier was Black pearls 2000 which was not doped. The catalyst was used to prepare 2,5-diformylfuran according to the method of Example 9. The catalytic reaction results are listed in Table 1.

[0101] Table 1

[0102]

[0103] It can be seen from the results in Table 1 that in the reaction of preparing 2,5-diformylfuran, the target product is 2,5-diformylfuran, and the byproduct is the product of continued oxidation, 5-formyl-2-furancarboxylic acid. Comparing the results of Example 9 with those of Comparative Examples 1-2, it can be seen that when synthesizing 2,5-diformylfuran using 5-hydroxymethylfurfural, the carbon-containing carrier is subjected to nitrogen doping treatment, and then the nitrogen-doped carbon carrier is impregnated with the active metal component compound solution to obtain a precious metal catalyst, which can significantly improve the selectivity of 2,5-diformylfuran even in the presence of high concentrations of 5-hydroxymethylfurfural.

[0104] In addition, the cyclic reaction was carried out according to the method of Example 9. After the catalyst was recycled 8 times, the conversion rate of 5-hydroxymethylfurfural was 100%, and the selectivity of 2,5-diformylfuran was still basically around 98%, indicating that the corresponding catalyst in the method of the present invention has improved stability and recycling performance.

[0105] The preferred embodiments of the present disclosure are described in detail above; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0106] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0107] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A method for preparing 2,5-diformylfuran, characterized in that: The preparation method comprises: SS1, dissolving 5-hydroxymethylfurfural in an organic solvent to obtain a mixed solution; SS2. Adding a selective oxidation catalyst to the mixed solution without adding alkali to carry out an oxidation reaction; the conditions of the oxidation reaction include: an oxygen partial pressure of 0.05 MPa-2 MPa; a reaction temperature of 50° C.-200° C.; The organic solvent is selected from one or more of toluene, dioxane, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethyl sulfoxide, tetrahydrofuran, pyridine and acetonitrile; the mass ratio of the organic solvent to 5-hydroxymethylfurfural is 2-50:1; the molar ratio of 5-hydroxymethylfurfural to the active metal component in the selective oxidation catalyst is 100-320:1; The selective oxidation catalyst comprises a nitrogen-doped carbon support and an active metal component; the specific surface area of ​​the nitrogen-doped carbon support is 200-2500 m 2 / g; in the nitrogen-doped carbon carrier, the mass fraction of nitrogen is 0.01-5% by weight, and the mass fraction of oxygen is 3-15% by weight; based on the weight of the selective oxidation catalyst, the content of the active metal component is 1-25% by weight; the active metal component compound is selected from oxides of metals of Group VIII; the N of the nitrogen-doped carbon carrier analyzed by XPS is 1s In the spectrum, there are characteristic peaks between 399-400.5 eV; The preparation method of the selective oxidation catalyst comprises the following steps: S1, impregnating the carbonaceous material with an aqueous solution containing nitrogen, drying it, and then performing a first calcination in an inert gas to obtain a nitrogen-doped carbon support; S2, mixing the nitrogen-doped carbon support with an active metal component compound solution to obtain a first mixture; S3, subjecting the first mixture to a first drying and a first reduction; Wherein, the specific surface area of ​​the carbonaceous material is 800-1800m 2 / g; the carbon-containing material is at least one of untreated activated carbon and / or carbon black; the aqueous solution containing nitrogen is selected from ammonia solution and / or urea solution; the active metal component compound is selected from soluble metal compounds of Group VIII metals; the temperature of the first calcination is 1000-1500°C; The Group VIII metal is selected from at least one of rhodium, palladium and ruthenium.

2. The method according to claim 1, wherein: The mass ratio of the carbon-containing material to the nitrogen element is 30:1-1:

2.

3. The method according to claim 1, wherein: The mass ratio of the carbon-containing material to the nitrogen element is 25:1-1:

1.

4. The method according to claim 1, wherein: The soluble metal compound of the Group VIII metal is at least one of a nitrate, an acetate, a soluble carbonate, a chloride and a soluble complex of the Group VIII metal.

5. The method according to claim 1, wherein: The active metal component compound is a chloride of a Group VIII metal.

6. The method according to claim 1, wherein: The active metal component compound is ruthenium chloride.

7. The method according to claim 1, wherein: Based on the mass of the catalyst, the mass fraction of the active metal component elements is 1%-25%.

8. The method according to claim 7, wherein: Based on the mass of the catalyst, the mass fraction of the active metal component elements is 5%-15%.

9. The method according to claim 1, wherein: In step S1, the immersion conditions include: immersion temperature of 15-40°C; immersion time of 12-36 hours; The first calcination conditions include: calcination temperature of 1100-1300° C.; calcination time of 2-12 hours; In step S2, the mixing is isochoric impregnation mixing; the mixing conditions include: mixing temperature of 15-40° C.; mixing time of 12-36 hours; In step S3, the first drying conditions include: drying temperature of 60-140°C; drying time of 6-24 hours; The first reduction conditions include: being carried out in a reducing atmosphere containing hydrogen; the reduction temperature is 200-800° C.; and the reduction time is 2-6 hours.

10. The method according to claim 9, wherein: In step S1, the immersion conditions include: immersion temperature is 20-30°C; immersion time is 18-24 hours; The first calcination time is 4-8 hours; In step S2, the mixing conditions include: mixing temperature of 20-30°C; mixing time of 18-28 hours; In step S3, the first drying conditions include: drying temperature of 90-120°C; drying time of 10-18 hours; The first reduction conditions include: the reducing atmosphere contains 10-100 volume % of hydrogen and 0-90 volume % of inert gas; the reduction temperature is 350-650° C.; and the reduction time is 2.5-4.5 hours.

11. The method according to claim 1, wherein: The oxide of the Group VIII metal is an oxide of at least one of rhodium, palladium and ruthenium.

12. The method according to claim 11, wherein: The oxide of the Group VIII metal is an oxide of ruthenium.

13. The preparation method according to claim 1, wherein: The mass ratio of the organic solvent to 5-hydroxymethylfurfural is 5-20:

1.

14. The preparation method according to claim 1, wherein: In step SS2, the reaction time is 0.5 h-10 h.

15. The preparation method according to claim 14, wherein: In step SS2, the conditions of the oxidation reaction include: oxygen partial pressure of 0.5 MPa-1 MPa; reaction temperature of 80° C.-120° C.; reaction time of 1 h-4 h.

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