Application of a composite manganese-based heterogeneous catalyst in catalyzing the selective oxidation of HMF to DFF or FDCA

Abstract

The invention discloses an application of a composite manganese-based heterogeneous catalyst in catalyzing the selective oxidation of 5-hydroxymethylfurfural (HMF) to produce 2,5-furandicarboxaldehyde (DFF) or 2,5-furandicarboxylic acid (FDCA), wherein the catalyst is composed of an in-situ composite of manganese oxide and carbonate, and the molar ratio of MnCO3 crystal form to MnO2 crystal form is 10:90-30:70. The composite manganese-based heterogeneous catalyst provided by the invention is applied to the HMF oxidation reaction, wherein the selective oxidation of HMF to produce DFF is catalyzed, and when the HMF concentration is 12.5 mmol·L ‑1 When the HMF concentration was 51.5mmol·L ‑1 When DFF is used, the highest production efficiency can reach 36.7mmol·g ‑1 ·h ‑1 The catalyst can also catalyze the oxidation of HMF to FDCA, with the selectivity of FDCA reaching up to 98.3%. The composite manganese-based heterogeneous catalyst is easy to prepare and can achieve high-efficiency selective oxidation of HMF under mild conditions. The product generation efficiency is high, easy to separate, and environmentally friendly.

Description

Technical Field

[0001] The invention belongs to the field of biomass energy chemical industry or composite catalyst technology, and particularly relates to the preparation of a (composite) manganese-based heterogeneous catalyst and its application in catalyzing the oxidation of 5-hydroxymethylfurfural. Background Art

[0002] The massive consumption of fossil fuels and increasingly severe environmental problems have forced people to seek sustainable energy resources. Unlike fossil resources, biomass refers to various organisms formed through photosynthesis and is widely used due to its abundant reserves and renewable characteristics.

[0003] Among them, 5-hydroxymethylfurfural (HMF) is considered to be an important biomass platform compound, which can be used to produce high-value-added chemicals and fuels through oxidation, hydrogenation, esterification and other conversion pathways. HMF is selectively oxidized to produce 2,5-furandicarboxaldehyde (DFF) and 2,5-furandicarboxylic acid (FDCA). Because DFF and FDCA have a wide range of potential applications in polymer synthesis, biomedicine and fire protection, they have attracted much attention in basic research and industrial fields in recent years. At present, the selective oxidation system for catalyzing HMF has gradually shifted from expensive gold-based, platinum-based, ruthenium-based and other precious metal catalysts to vanadium-based, manganese-based, copper-based and other non-precious metal catalysts.

[0004] Among them, manganese-based spinel (MnCo 2 O 4 and CoMn 2 O 4 Manganese-based oxides such as CoMn, etc., composite manganese-based oxides, and manganese dioxide have excellent catalytic effects in the HMF oxidation reaction (Table 1). 2 O 4 The conversion rate of the catalyst can reach 41.6%, the DFF selectivity can reach 100.0%, and the production efficiency of the catalyst (referred to as production efficiency) can reach 2.1mmol·g -1 ·h -1 ; MnO x / MnCO 3 The conversion rate of the catalyst can reach 28.0%, the DFF selectivity can reach 97.0%, and the production efficiency of the catalyst can reach 9.7mmol·g -1 ·h -1 ; MnO x / MnCO 3 / Fe 2 O 3 The conversion rate of the catalyst can reach 48.0%, the DFF selectivity can reach 100.0%, and the production efficiency of the catalyst can reach 2.4mmol·g -1 ·h -1Therefore, the research on manganese-based spinel in HMF selective oxidation system needs to be developed and improved. Based on the previous work of our research group, we took the lead in constructing a multiphase system for HMF selective oxidation on manganese-based spinel catalysts, aiming to develop a more efficient composite manganese-based multiphase catalyst for the selective oxidation of HMF. Summary of the invention

[0005] Purpose of the invention: The purpose of the present invention is to provide an application of a composite manganese-based heterogeneous catalyst in catalyzing the selective oxidation of HMF to produce DFF or FDCA. The composite manganese-based heterogeneous catalyst provided by the present invention is applied to the oxidation reaction of 5-hydroxymethylfurfural (HMF), wherein the selective oxidation of HMF to produce 2,5-furandicarboxaldehyde (DFF) is catalyzed. When the HMF concentration is 12.5 mmol·L -1 When the HMF concentration was 51.5mmol·L -1 The maximum DFF production efficiency can reach 36.7mmol·g -1 .h -1 The composite manganese-based heterogeneous catalyst can also catalyze the oxidation of HMF to produce 2,5-furandicarboxylic acid (FDCA), with the selectivity of FDCA reaching up to 98.3%.

[0006] In order to solve the technical problem of the present invention, the technical solution is as follows: an application of a composite manganese-based heterogeneous catalyst in catalyzing the selective oxidation of HMF to produce DFF or FDCA, HMF, a composite manganese-based heterogeneous catalyst, a magneton, and DMF as a solvent are added to a three-necked flask, and the mixture is heated at a flow rate of 10 mL min -1 , 90-120°C and a composite manganese-based heterogeneous catalyst for reaction for 15-120 min to synthesize DFF;

[0007] HMF, composite manganese-based heterogeneous catalyst, magneton, H 2 O and 2 equivalents of KHCO 3 Add to the autoclave, at a flow rate of 0.2-2.0 MPa O 2 , 90-130°C and a composite manganese-based heterogeneous catalyst for 0.5h-6h to synthesize FDCA;

[0008] The composite manganese-based heterogeneous catalyst is MnCO 3 As precursor, a series of MnCO 3 Crystal form and MnO 2 The molar ratio of the crystal form is 10:90-30:70 catalyst, the MnCO 3 It is obtained by precipitation from Na 2 CO 3 and Mn(NO 3 )2 ·4H 2 O made;

[0009] The calcination conditions are calcination atmosphere and calcination temperature. The calcination atmosphere is an air muffle furnace, a nitrogen tubular furnace, an air tubular furnace or a 10% H 2 -N 2 Tube furnace, the calcination temperature is 300°C-450°C.

[0010] Preferably, the composite manganese-based heterogeneous catalyst is used in catalyzing the selective oxidation of HMF to prepare DFF and FDCA. 0.25 mmol or 1.0 mmol HMF, the composite manganese-based heterogeneous catalyst, a magnet, and 20 mL DMF as a solvent are added to a three-necked flask and heated at a flow rate of 10 mL min -1 , 90-120°C and 0.02g-0.1g of composite manganese-based heterogeneous catalyst for 0.25h-2h to synthesize DFF;

[0011] 0.5 mmol HMF, composite manganese-based heterogeneous catalyst, magnetic particle, 10 mL H 2 O and 2 equivalents of KHCO 3 Add to the high pressure reactor, at 1.0-2.0MPa O 2 , 90-130°C and 0.1g-0.2g of composite manganese-based heterogeneous catalyst for 0.5h-6h to synthesize FDCA;

[0012] The calcination atmosphere is an air muffle furnace, and the calcination temperature is 300°C.

[0013] Preferably, the composite manganese-based heterogeneous catalyst is used in catalyzing the selective oxidation of HMF to produce DFF or FDCA. 1.2 g of sodium carbonate is dissolved in 45 mL of ultrapure water and ultrasonicated for 5 min to mix evenly. 50% of Mn(NO 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared MnCO at 600rpm. 3 The prepared solution was stirred for 3 h and aged for 15 min. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80 °C for 12 h to obtain MnCO 3 .

[0014] Preferably, the composite manganese-based heterogeneous catalyst is used to catalyze the selective oxidation of HMF to produce DFF or FDCA, and the obtained MnCO 3 In a muffle furnace at 2 °C min -1 The heating rate was maintained at 300℃ for 2h, and MnCO 3 Crystal form and MnO2 The molar ratio of the crystal form is 31:69, and the Mn-2 catalyst is obtained;

[0015] The obtained MnCO 3 In a muffle furnace at 2 °C min -1 The heating rate was maintained at 400℃ for 2h, and MnCO 3 Crystal form and MnO 2 The molar ratio of the crystal form is 27:73, and the Mn-3 catalyst is obtained;

[0016] The obtained MnCO 3 In a muffle furnace at 2 °C min -1 The heating rate was maintained at 450℃ for 2h, and MnCO 3 Crystal form and MnO 2 The molar ratio of the crystal form is 25:75, and the Mn-4 catalyst is obtained;

[0017] The obtained MnCO 3 In a nitrogen tube furnace at 2 °C min -1 The heating rate was maintained at 400℃ for 2h, and different protective gases were used for calcination, and its crystal form also changed to obtain Mn-6 catalyst;

[0018] The obtained MnCO 3 At 10% H 2 -90% N 2 Tube furnace at 2℃·min -1 The heating rate was maintained at 400℃ for 2h, and different protective gases were used for calcination, and its crystal form also changed to obtain Mn-7 catalyst;

[0019] The obtained MnCO 3 In a muffle furnace at 5 °C min -1 The heating rate was maintained at 300℃ for 2h. The crystal form of the catalyst changed when the heating rate was changed to obtain Mn-8 catalyst.

[0020] The obtained MnCO 3 In a muffle furnace at 10 °C min -1 The heating rate was maintained at 300℃ for 2h. The crystal form of the catalyst changed when the heating rate was changed to obtain Mn-9 catalyst.

[0021] The obtained MnCO 3 In a muffle furnace at 5 °C min -1 The heating rate was maintained at 300℃ for 3h. The crystal form also changed with different calcination times to obtain Mn-10 catalyst.

[0022] The obtained MnCO 3 In a muffle furnace at 10 °C min -1 The heating rate was maintained at 300℃ for 3h. The crystal form also changed with different calcination times to obtain Mn-11 catalyst.

[0023] The obtained MnCO 3 In an air tube furnace at 2℃·min -1 The heating rate was maintained at 300℃ for 2h, and different protective gases were used for calcination, and its crystal form also changed to obtain Mn-12 catalyst;

[0024] The obtained MnCO 3 In an air tube furnace at 2℃·min -1 The heating rate was maintained at 400°C for 2 hours. When different protective gases or calcination temperatures were used, the crystal form also changed to obtain Mn-13 catalyst.

[0025] Preferably, the use of the composite manganese-based heterogeneous catalyst in catalyzing the selective oxidation of HMF to produce DFF or FDCA is characterized by:

[0026] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared MnCO at 600rpm. 3 The prepared solution was stirred for 3 h and aged for 15 min. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80 °C for 12 h to obtain MnCO 3 ;

[0027] The obtained MnCO 3 In a muffle furnace at 2 °C min -1 The heating rate was maintained at 300℃ for 2h, and MnCO 3 Crystal form and MnO 2 The molar ratio of the crystal form was 31:69 to obtain Mn-2 catalyst; oxygen was used as the reaction atmosphere at 10 mL min -1 50 mg Mn-2 catalyst, 129.8 mg HMF and 20 mL DMF were added to the autoclave in sequence and reacted at 120 °C for 30 min. The conversion rate was 97.1%, the DFF selectivity was 91.8%, and the production efficiency was 36.7 mmol·g -1 ·h -1 .

[0028] Preferably, the composite manganese-based heterogeneous catalyst is used to catalyze the selective oxidation of HMF to produce DFF or FDCA, and the obtained MnCO 3 In a muffle furnace at 2 °C min -1 The heating rate was maintained at 300℃ for 2h, and MnCO 3 Crystal form and MnO 2 The molar ratio of the crystal form was 31:69 to obtain Mn-2 catalyst; oxygen was used as the reaction atmosphere at 10 mL min -1 50 mg Mn-2 catalyst, 32 mg HMF and 20 mL DMF were added to the autoclave in sequence and reacted at 120 °C for 30 min. The conversion rate was 97.1%, the DFF selectivity was 96.3%, and the production efficiency was 9.4 mmol·g -1 ·h -1 .

[0029] Preferably, the composite manganese-based heterogeneous catalyst is used in catalyzing the selective oxidation of HMF to produce DFF or FDCA. 1.2 g of sodium carbonate is dissolved in 45 mL of ultrapure water and ultrasonicated for 5 min to mix evenly. 50% of Mn(NO 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared MnCO at 600rpm. 3 The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 ; The obtained MnCO 3 The Mn-2 catalyst was obtained by calcining at 300°C in a muffle furnace for 2 h. 1 MPa O 2 0.2 g Mn-2 catalyst, 63 mg HMF, 10 mL H 2 O and 2 equivalents of KHCO 3 After reacting at 120°C for 6 h, the conversion of HMF was 100.0% and the selectivity of FDCA was 98.3%.

[0030] Beneficial effects:

[0031] Compared with traditional precious metal catalysts, it has high HMF conversion efficiency and good target product selectivity. Non-precious metal catalysts such as manganese, iron, vanadium, etc. have attracted much attention due to their low price and abundant reserves. The composite manganese-based catalyst of the present invention is used to prepare a series of catalysts by precipitation and calcination methods; by changing the calcination conditions and adjusting the ratio of oxides and carbonates, a catalyst with excellent catalytic performance is obtained.

[0032] The present invention discloses a composite manganese-based heterogeneous catalyst and a preparation method and application thereof. The catalyst is composed of an in-situ composite of manganese oxide and carbonate, including MnO 2 Crystal form and MnCO 3 Crystal form; the MnCO 3 Crystal form and MnO 2 The molar ratio of the crystal form is 10:90-30:70.

[0033] The composite manganese-based heterogeneous catalyst provided by the present invention is applied to the oxidation reaction of 5-hydroxymethylfurfural (HMF), wherein the selective oxidation of HMF to produce DFF is catalyzed. When the HMF concentration is 12.5 mmol·L -1 When the HMF concentration was 51.5mmol·L -1 The maximum DFF production efficiency can reach 36.7mmol·g -1 ·h -1 The catalyst can also catalyze the oxidation of HMF to produce 2,5-furandicarboxylic acid (FDCA), and the selectivity of FDCA can reach up to 98.3%. The advantages of the present invention are: the composite manganese-based heterogeneous catalyst provided is easy to prepare, can achieve high-efficiency selective oxidation of 5-hydroxymethylfurfural under mild conditions, has high product generation efficiency, is easy to separate, is green and environmentally friendly, and has important guiding significance for achieving industrial-scale production of selective oxidation of 5-hydroxymethylfurfural.

[0034] Manganese-based catalysts are low in cost and have excellent activity. In the HMF selective oxidation system to DFF, when the HMF concentration is 12.5 mmol·L -1 When the HMF concentration was 51.5mmol·L -1 The maximum DFF production efficiency can reach 36.7mmol·g -1 ·h -1 (See Examples 3 and 31). In the HMF selective oxidation system to produce FDCA, the HMF conversion rate and FDCA selectivity can reach up to 100.0% and 98.3% (See Example 36). In the manganese-based heterogeneous catalytic system, the composite manganese-based heterogeneous catalyst we constructed has a higher DFF production efficiency than the catalyst in the current reported documents. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is the XRD pattern of the prepared catalyst;

[0036] Figure 2 This is the catalytic cycle diagram of the prepared catalyst. DETAILED DESCRIPTION

[0037] Example 1

[0038] Oxygen was used as the reaction atmosphere at a rate of 10 mL min -1 50 mg of commercial MnCO was added into the three-necked flask in sequence. 3 , 32 mg HMF and 20 mL DMF were reacted at 120 °C for 30 min, the conversion rate was 0.5%, the DFF selectivity was 100.0%, and the production efficiency was 0.1 mmol·g -1 ·h -1 .

[0039] Example 2

[0040] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared Na 2 CO 3 The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 The obtained MnCO 3 In a muffle furnace at 2 °C min -1 The heating rate was maintained at 200℃ for 2h, and the crystalline form after calcination was MnCO 3 Oxygen was used as the reaction atmosphere at a rate of 10 mL min -1 50 mg Mn-1 catalyst, 32 mg HMF and 20 mL DMF were added into a three-necked flask in sequence and reacted at 120 °C for 30 min. The conversion rate was 5.4%, the DFF selectivity was 100.0%, and the production efficiency was 0.5 mmol·g -1 ·h -1 .

[0041] Summary: Preparation and calcination of MnCO in the laboratory 3 The catalyst effect is significantly better than commercial MnCO 3 catalytic effect.

[0042] Example 3

[0043] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared Na2 CO 3 The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 The obtained MnCO 3 In a muffle furnace at 2 °C min -1 The heating rate was maintained at 300℃ for 2h, and MnCO 3 Crystal form and MnO 2 The molar ratio of the crystal form was 31:69, and Mn-2 catalyst was obtained. Oxygen was used as the reaction atmosphere at 10 mL min -1 50 mg Mn-2 catalyst, 32 mg HMF and 20 mL DMF were added into a three-necked flask in sequence and reacted at 120 °C for 30 min. The conversion rate was 97.1%, the DFF selectivity was 96.3%, and the production efficiency was 9.4 mmol·g -1 ·h -1 .

[0044] Example 4

[0045] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared Na 2 CO 3 The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 The obtained MnCO 3 In a muffle furnace at 2 °C min -1 The heating rate was maintained at 400℃ for 2h, and MnCO 3 Crystal form and MnO 2 The molar ratio of the crystal form was 27:73, and Mn-3 catalyst was obtained. Oxygen was used as the reaction atmosphere at 10 mL min -1 50 mg Mn-3 catalyst, 32 mg HMF and 20 mL DMF were added into a three-necked flask in sequence and reacted at 120 °C for 30 min. The conversion rate was 85.5%, the DFF selectivity was 97.3%, and the production efficiency was 8.3 mmol·g -1 ·h -1 .

[0046] Example 5

[0047] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared Na 2 CO 3 The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 The obtained MnCO 3 In a muffle furnace at 2 °C min -1 The heating rate was maintained at 450℃ for 2h, and MnCO 3 Crystal form and MnO 2 The molar ratio of the crystal form was 25:75, and Mn-4 catalyst was obtained. Oxygen was used as the reaction atmosphere at 10 mL min -1 50 mg Mn-4 catalyst, 32 mg HMF and 20 mL DMF were added to a three-necked flask and reacted at 120 °C for 30 min. The conversion rate was 78.4%, the DFF selectivity was 97.8%, and the production efficiency was 7.7 mmol·g -1 ·h -1 .

[0048] Example 6

[0049] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared Na 2 CO 3 The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 The obtained MnCO 3 In a muffle furnace at 2 °C min -1 The heating rate is maintained at 700℃ for 2h, and the crystal form after calcination is Mn 2 O 3 , and Mn-5 catalyst was obtained. Oxygen was used as the reaction atmosphere at 10 mL min -150 mg Mn-5 catalyst, 32 mg HMF and 20 mL DMF were added into a three-necked flask in sequence and reacted at 120 °C for 30 min. The conversion rate was 9.4%, the DFF selectivity was 94.6%, and the production efficiency was 0.9 mmol·g -1 ·h -1 .

[0050] Example 7

[0051] Commercial MnO 2 In a muffle furnace at 2 °C min -1 The heating rate was maintained at 700℃ for 2h to obtain MnO 2 -1 catalyst. Oxygen was used as the reaction atmosphere at 10 mL min -1 50 mg MnO was added into the three-necked flask. 2 -1 catalyst, 32 mg HMF and 20 mL DMF and reacted at 120 °C for 30 min, the conversion rate was 24.1%, the DFF selectivity was 99.5%, and the production efficiency was 2.4 mmol·g -1 ·h -1 .

[0052] Summary: MnCO prepared in the laboratory 3 Calcination is performed and the calcination temperature is changed, and its crystal form also changes; with the increase of calcination temperature, MnO 2 The molar amount of the crystal form gradually increases. 3 Crystal form and MnO 2 When the molar ratio of the crystal form is 31:69 (Example 3), the catalytic effect is the best.

[0053] Example 8

[0054] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared Na 2 CO 3 The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 The obtained MnCO 3 In a nitrogen tube furnace at 2 °C min -1 The heating rate was maintained at 400℃ for 2h, and its crystal form changed to obtain Mn-6 catalyst. Oxygen was used as the reaction atmosphere at a rate of 10mL min-1 50 mg Mn-6 catalyst, 32 mg HMF and 20 mL DMF were added into a three-necked flask in sequence and reacted at 120 °C for 30 min. The conversion rate was 33.4%, the DFF selectivity was 97.8%, and the production efficiency was 3.3 mmol·g -1 ·h -1 .

[0055] Example 9

[0056] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared Na 2 CO 3 The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 The obtained MnCO 3 At 10% H 2 -N 2 Tube furnace at 2℃·min -1 The heating rate was maintained at 400℃ for 2h, and the crystal form changed to obtain Mn-7 catalyst. Oxygen was used as the reaction atmosphere at a rate of 10mL min -1 50 mg Mn-7 catalyst, 32 mg HMF and 20 mL DMF were added to a three-necked flask in sequence and reacted at 120 °C for 30 min. The conversion rate was 31.7%, the DFF selectivity was 94.5%, and the production efficiency was 3.0 mmol·g -1 ·h -1 .

[0057] Summary: The catalytic performance of the composite manganese-based heterogeneous catalysts obtained by calcining at different atmospheres and temperatures is different. The catalyst obtained by calcining at 300°C in an air muffle furnace for 2 hours has the best performance. (See Examples 3-9)

[0058] Example 10

[0059] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared Na 2 CO 3The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 The obtained MnCO 3 In a muffle furnace at 5 °C min -1 The heating rate was maintained at 300℃ for 2h to obtain Mn-8 catalyst. Oxygen was used as the reaction atmosphere at a rate of 10mL min -1 50 mg Mn-8 catalyst, 32 mg HMF and 20 mL DMF were added to a three-necked flask in sequence and reacted at 120 °C for 30 min. The conversion rate was 98.3%, the DFF selectivity was 96.1%, and the production efficiency was 9.4 mmol·g -1 ·h -1 .

[0060] Embodiment 11

[0061] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared Na 2 CO 3 The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 The obtained MnCO 3 In a muffle furnace at 10 °C min -1 The heating rate was maintained at 300℃ for 2h to obtain Mn-9 catalyst. Oxygen was used as the reaction atmosphere at a rate of 10mL min -1 50 mg Mn-9 catalyst, 32 mg HMF and 20 mL DMF were added into a three-necked flask in sequence and reacted at 120 °C for 30 min. The conversion rate was 96.1%, the DFF selectivity was 95.3%, and the production efficiency was 9.2 mmol·g -1 ·h -1 .

[0062] Example 12

[0063] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared Na2 CO 3 The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 The obtained MnCO 3 In a muffle furnace at 5 °C min -1 The heating rate was maintained at 300℃ for 3h to obtain Mn-10 catalyst. Oxygen was used as the reaction atmosphere at a rate of 10mL min -1 50 mg Mn-10 catalyst, 32 mg HMF and 20 mL DMF were added to a three-necked flask in sequence and reacted at 120 °C for 60 min. The conversion rate was 97.7%, the DFF selectivity was 95.6%, and the production efficiency was 4.7 mmol·g -1 ·h -1 .

[0064] Example 13

[0065] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared Na 2 CO 3 The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 The obtained MnCO 3 In a muffle furnace at 5 °C min -1 The heating rate was maintained at 300℃ for 2h to obtain Mn-8 catalyst. Oxygen was used as the reaction atmosphere at a rate of 10mL min -1 50 mg Mn-8 catalyst, 32 mg HMF and 20 mL DMF were added to a three-necked flask in sequence and reacted at 120 °C for 60 min. The conversion rate was 98.3%, the DFF selectivity was 96.1%, and the production efficiency was 4.7 mmol·g -1 ·h -1 .

[0066] Embodiment 14

[0067] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 ) 2 ·4H 2O solution 2mL, added dropwise to the prepared Na 2 CO 3 The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 The obtained MnCO 3 In a muffle furnace at 10 °C min -1 The heating rate was maintained at 300℃ for 3h to obtain Mn-11 catalyst. Oxygen was used as the reaction atmosphere at a rate of 10mL min -1 50 mg Mn-11 catalyst, 32 mg HMF and 20 mL DMF were added to a three-necked flask in sequence and reacted at 120 °C for 60 min. The conversion rate was 97.5%, the DFF selectivity was 96.4%, and the production efficiency was 4.7 mmol·g -1 ·h -1 .

[0068] Embodiment 15

[0069] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared Na 2 CO 3 The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 The obtained MnCO 3 In a muffle furnace at 10 °C min -1 The heating rate was maintained at 300℃ for 2h to obtain Mn-9 catalyst. Oxygen was used as the reaction atmosphere at a rate of 10mL min -1 50 mg Mn-9 catalyst, 32 mg HMF and 20 mL DMF were added to a three-necked flask in sequence and reacted at 120 °C for 60 min. The conversion rate was 96.1%, the DFF selectivity was 95.3%, and the production efficiency was 4.6 mmol·g -1 ·h -1 .

[0070] Example 16

[0071] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 )2 ·4H 2 O solution 2mL, added dropwise to the prepared Na 2 CO 3 The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 The obtained MnCO 3 In an air tube furnace at 2℃·min -1 The heating rate was maintained at 300℃ for 2h to obtain Mn-12 catalyst. Oxygen was used as the reaction atmosphere at a rate of 10mL min -1 50 mg Mn-12 catalyst, 32 mg HMF and 20 mL DMF were added into a three-necked flask in sequence and reacted at 120 °C for 30 min. The conversion rate was 83.2%, the DFF selectivity was 98.3%, and the production efficiency was 8.2 mmol·g -1 ·h -1 .

[0072] Summary: Changing the heating rate and calcination time during calcination has little effect on the conversion rate and selectivity of HMF, but has an effect on the production efficiency of DFF (see Examples 10-15). The production efficiency of Examples 3 and 10 is the highest; comparing the catalyst effects after calcination in an air tube furnace and an air muffle furnace, the HMF conversion rate and DFF selectivity of the air muffle furnace are higher (see Examples 3 and 16).

[0073] Embodiment 17

[0074] Oxygen was used as the reaction atmosphere at a rate of 10 mL min -1 0.1 g of commercial MnO 2 , 32 mg HMF and 20 mL DMF were reacted at 120 °C for 60 min, the conversion rate was 59.7%, the DFF selectivity was 99.7%, and the production efficiency was 1.5 mmol·g -1 ·h -1 .

[0075] Embodiment 18

[0076] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared Na 2 CO 3The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 The obtained MnCO 3 In an air tube furnace at 2℃·min -1 The heating rate was maintained at 400℃ for 2h to obtain Mn-13 catalyst. Oxygen was used as the reaction atmosphere at a rate of 10mL min -1 0.1 g Mn-13 catalyst, 32 mg HMF and 20 mL DMF were added to a three-necked flask in sequence and reacted at 120 °C for 60 min. The conversion rate was 100.0%, the DFF selectivity was 97.2%, and the production efficiency was 2.4 mmol·g -1 ·h -1 .

[0077] Conclusion: It is demonstrated that the catalyst prepared in the laboratory is superior to commercial MnO 2 The catalytic effect is good (see Examples 17 and 18).

[0078] Embodiment 19

[0079] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared Na 2 CO 3 The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 The obtained MnCO 3 In an air tube furnace at 2℃·min -1 The heating rate was maintained at 400℃ for 2h to obtain Mn-13 catalyst. Oxygen was used as the reaction atmosphere at a rate of 10mL min -1 0.1 g Mn-13 catalyst, 32 mg HMF and 20 mL DMF were added to a three-necked flask in sequence and reacted at 90 °C for 60 min. The conversion rate was 85.0%, the DFF selectivity was 99.4%, and the production efficiency was 2.1 mmol·g -1 ·h -1 .

[0080] Embodiment 20

[0081] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared Na 2 CO 3 The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 The obtained MnCO 3 In an air tube furnace at 2℃·min -1 The heating rate was maintained at 400℃ for 2h to obtain Mn-13 catalyst. Oxygen was used as the reaction atmosphere at a rate of 10mL min -1 0.1 g Mn-13 catalyst, 32 mg HMF and 20 mL DMF were added to a three-necked flask in sequence and reacted at 100 °C for 60 min. The conversion rate was 95.0%, the DFF selectivity was 98.7%, and the production efficiency was 2.3 mmol·g -1 ·h -1 .

[0082] In summary, when other conditions remain unchanged and only the reaction temperature is changed, as the reaction temperature increases, the conversion rate and production efficiency continue to increase, and the selectivity is maintained above 97% (see Examples 18-20).

[0083] Embodiment 21

[0084] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared Na 2 CO 3 The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 MnCO 3 The catalyst Mn-2 was obtained by calcining at 300℃ in a muffle furnace for 2h. Oxygen was used as the reaction atmosphere at a rate of 10mL min -10.05 g Mn-2 catalyst, 32 mg HMF and 20 mL DMF were added to a three-necked flask in sequence and reacted at 120 °C for 15 min. The conversion rate was 86.4%, the DFF selectivity was 98.4%, and the production efficiency was 17.0 mmol·g -1 ·h -1 .

[0085] Embodiment 22

[0086] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared Na 2 CO 3 The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 MnCO 3 The catalyst Mn-2 was obtained by calcining at 300℃ in a muffle furnace for 2h. Oxygen was used as the reaction atmosphere at a rate of 10mL min -1 0.05 g Mn-2 catalyst, 32 mg HMF and 20 mL DMF were added to a three-necked flask in sequence and reacted at 120 °C for 60 min. The conversion rate was 96.8%, the DFF selectivity was 96.7%, and the production efficiency was 4.7 mmol·g -1 ·h -1 .

[0087] In summary: when the amount of catalyst was 0.05 g and other reaction conditions were not changed, as the reaction time increased, the conversion rate gradually increased, the selectivity was maintained at about 97%, and the production efficiency decreased (see Examples 3, 21 and 22).

[0088] Embodiment 23

[0089] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared Na 2 CO 3 The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3MnCO 3 The catalyst Mn-2 was obtained by calcining at 300℃ in a muffle furnace for 2h. Oxygen was used as the reaction atmosphere at a rate of 10mL min -1 0.1 g Mn-2 catalyst, 32 mg HMF and 20 mL DMF were added to a three-necked flask in sequence and reacted at 120 °C for 15 min. The conversion rate was 98.3%, the DFF selectivity was 96.9%, and the production efficiency was 9.5 mmol·g -1 ·h -1 .

[0090] Embodiment 24

[0091] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared Na 2 CO 3 The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 MnCO 3 The catalyst Mn-2 was obtained by calcining at 300℃ in a muffle furnace for 2h. Oxygen was used as the reaction atmosphere at a rate of 10mL min -1 0.1 g Mn-2 catalyst, 32 mg HMF and 20 mL DMF were added to a three-necked flask in sequence and reacted at 120 °C for 30 min. The conversion rate was 100.0%, the DFF selectivity was 96.7%, and the production efficiency was 4.8 mmol·g -1 ·h -1 .

[0092] Embodiment 25

[0093] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared Na 2 CO 3 The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 MnCO 3The catalyst Mn-2 was obtained by calcining at 300℃ in a muffle furnace for 2h. Oxygen was used as the reaction atmosphere at a rate of 10mL min -1 0.1 g Mn-2 catalyst, 32 mg HMF and 20 mL DMF were added to a three-necked flask in sequence and reacted at 120 °C for 60 min. The conversion rate was 100.0%, the DFF selectivity was 94.3%, and the production efficiency was 2.4 mmol·g -1 ·h -1 .

[0094] In summary: when the amount of catalyst is 0.1 g and other reaction conditions are not changed, as the reaction time increases, the conversion rate gradually increases and reaches 100%, the selectivity can be maintained at about 97%, and the production efficiency gradually decreases (see Examples 23-25).

[0095] Embodiment 26

[0096] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared Na 2 CO 3 The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 The obtained MnCO 3 The catalyst Mn-2 was obtained by calcining at 300℃ in a muffle furnace for 2h. Oxygen was used as the reaction atmosphere at a rate of 10mL min -1 0.02 g Mn-2 catalyst, 32 mg HMF and 20 mL DMF were added to a three-necked flask in sequence and reacted at 120 °C for 15 min. The conversion rate was 57.0%, the DFF selectivity was 98.8%, and the production efficiency was 28.2 mmol·g -1 ·h -1 .

[0097] Embodiment 27

[0098] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared Na 2 CO 3The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 The obtained MnCO 3 The catalyst Mn-2 was obtained by calcining at 300℃ in a muffle furnace for 2h. Oxygen was used as the reaction atmosphere at a rate of 10mL min -1 0.02 g Mn-2 catalyst, 32 mg HMF and 20 mL DMF were added to a three-necked flask in sequence and reacted at 120 °C for 30 min. The conversion rate was 66.5%, the DFF selectivity was 98.6%, and the production efficiency was 16.4 mmol·g -1 ·h -1 .

[0099] Embodiment 28

[0100] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared Na 2 CO 3 The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 The obtained MnCO 3 The catalyst Mn-2 was obtained by calcining at 300℃ in a muffle furnace for 2h. Oxygen was used as the reaction atmosphere at a rate of 10mL min -1 0.02 g Mn-2 catalyst, 32 mg HMF and 20 mL DMF were added to a three-necked flask in sequence and reacted at 120 °C for 60 min. The conversion rate was 75.5%, the DFF selectivity was 98.0%, and the production efficiency was 9.2 mmol·g -1 ·h -1 .

[0101] Embodiment 29

[0102] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared Na 2 CO 3The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 The obtained MnCO 3 The catalyst Mn-2 was obtained by calcining at 300℃ in a muffle furnace for 2h. Oxygen was used as the reaction atmosphere at a rate of 10mL min -1 0.02 g Mn-2 catalyst, 32 mg HMF and 20 mL DMF were added to a three-necked flask in sequence and reacted at 120 °C for 90 min. The conversion rate was 80.2%, the DFF selectivity was 98.2%, and the production efficiency was 6.6 mmol·g -1 ·h -1 .

[0103] Embodiment 30

[0104] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared Na 2 CO 3 The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 The obtained MnCO 3 The catalyst Mn-2 was obtained by calcining at 300℃ in a muffle furnace for 2h. Oxygen was used as the reaction atmosphere at a rate of 10mL min -1 0.02 g Mn-2 catalyst, 32 mg HMF and 20 mL DMF were added to a three-necked flask in sequence and reacted at 120 °C for 120 min. The conversion of HMF was 83.0%, the selectivity of DFF was 98.2%, and the production efficiency was 5.1 mmol·g -1 ·h -1 .

[0105] In summary, when the catalyst amount was 0.02 g and other reaction conditions were not changed, as the reaction time increased, the conversion rate increased from 57% to 83%, the selectivity was maintained at about 98%, and the production efficiency increased from 28.2 mmol·g -1 ·h -1 Reduced to 5.1mmol·g -1 ·h -1 (See Examples 26-30).

[0106] Embodiment 31

[0107] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared Na 2 CO 3 The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 The obtained MnCO 3 In a muffle furnace at 2 °C min -1 The heating rate was maintained at 300℃ for 2h, and MnCO 3 Crystal form and MnO 2 The molar ratio of the crystal form was 31:69, and Mn-2 catalyst was obtained. Oxygen was used as the reaction atmosphere at 10 mL min -1 50 mg Mn-2 catalyst, 129.8 mg HMF and 20 mL DMF were added to a three-necked flask and reacted at 120 °C for 30 min. The conversion rate was 97.1%, the DFF selectivity was 91.8%, and the production efficiency was 36.7 mmol·g -1 ·h -1 .

[0108] Summary: When the HMF concentration is 12.5mmol·L -1 When the HMF concentration was 51.5mmol·L -1 When DFF is used, the highest production efficiency can reach 36.7mmol·g -1 ·h -1 .

[0109] Embodiment 32

[0110] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared Na 2 CO 3 The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 The obtained MnCO3 The catalyst Mn-2 was obtained by calcining at 300℃ in a muffle furnace for 2h. Oxygen was used as the reaction atmosphere at a rate of 10mL min -1 0.05 g Mn-2 catalyst, 32 mg HMF and 20 mL DMF were added to a three-necked flask in turn and reacted at 120 °C for 30 min. The experiment was repeated 5 times. The catalyst performance showed that the catalytic activity remained stable. The conversion rate of HMF remained at about 92%, the selectivity of DFF remained above 97%, and the production efficiency was 9.0 mmol·g -1 ·h -1 This indicates that the catalyst has excellent catalytic stability. Figure 1 )

[0111] Embodiment 33

[0112] 1MPa O 2 63 mg HMF, 10 mL H 2 O and 2 equivalents of KHCO 3 After reacting at 120°C for 6 h, the conversion of HMF was 45.2% and the selectivity of FDCA was 3.1%.

[0113] Embodiment 34

[0114] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared Na 2 CO 3 The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 The obtained MnCO 3 The catalyst was calcined at 300℃ in a muffle furnace for 2h to obtain Mn-2 catalyst. 1MPa O 2 0.05 g Mn-2 catalyst, 63 mg HMF, 10 mL H 2 O and 2 equivalents of KHCO 3 After reacting at 120°C for 6 h, the conversion of HMF was 93.5% and the selectivity of FDCA was 13.3%.

[0115] Embodiment 35

[0116] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared Na 2 CO 3 The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 The obtained MnCO 3 The catalyst was calcined at 300℃ in a muffle furnace for 2h to obtain Mn-2 catalyst. 1MPa O 2 0.1 g Mn-2 catalyst, 63 mg HMF, 10 mL H 2 O and 2 equivalents of KHCO 3 After reacting at 120°C for 6 h, the conversion of HMF was 100.0% and the selectivity of FDCA was 85.5%.

[0117] Embodiment 36

[0118] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared Na 2 CO 3 The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 The obtained MnCO 3 The catalyst was calcined at 300℃ in a muffle furnace for 2h to obtain Mn-2 catalyst. 1MPa O 2 0.15 g Mn-2 catalyst, 63 mg HMF, 10 mL H 2 O and 2 equivalents of KHCO 3 After reacting at 120°C for 6 h, the conversion of HMF was 100.0% and the selectivity of FDCA was 98.3%.

[0119] Embodiment 37

[0120] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 )2 ·4H 2 O solution 2mL, added dropwise to the prepared Na 2 CO 3 The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 The obtained MnCO 3 The catalyst was calcined at 300℃ in a muffle furnace for 2h to obtain Mn-2 catalyst. 1MPa O 2 0.2 g Mn-2 catalyst, 63 mg HMF, 10 mL H 2 O and 2 equivalents of KHCO 3 After reacting at 120°C for 6 h, the conversion of HMF was 100.0% and the selectivity of FDCA was 97.2%.

[0121] Summary: When the amount of catalyst is changed without changing other reaction conditions, the selectivity of FDCA increases by nearly 12% when the amount of catalyst increases from 0.1g to 0.2g, and 150mg is the optimal amount of catalyst. This indicates that the catalyst is beneficial to promote the selective conversion of HMF into FDCA. (See Examples 33-37)

[0122] Embodiment 38

[0123] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared Na 2 CO 3 The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 MnCO 3 The catalyst was calcined at 300℃ in a muffle furnace for 2h to obtain Mn-2 catalyst. 1MPa O 2 0.1 g Mn-2 catalyst, 63 mg HMF, 10 mL H 2 O and 2 equivalents of KHCO 3 After reacting at 90°C for 6 h, the conversion of HMF was 88.9% and the selectivity of FDCA was 13.7%.

[0124] Embodiment 39

[0125] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared Na 2 CO 3 The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 MnCO 3 The catalyst was calcined at 300℃ in a muffle furnace for 2h to obtain Mn-2 catalyst. 1MPa O 2 0.1 g Mn-2 catalyst, 63 mg HMF, 10 mL H 2 O and 2 equivalents of KHCO 3 After reacting at 110°C for 6 h, the conversion of HMF was 100% and the selectivity of FDCA was 56.9%.

[0126] Embodiment 40

[0127] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared Na 2 CO 3 The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 The obtained MnCO 3 The catalyst was calcined at 300°C in a muffle furnace for 2 h to obtain Mn-2 catalyst. 1.0 MPa O 2 0.1 g Mn-2 catalyst, 63 mg HMF, 10 mL H 2 O and 2 equivalents of KHCO 3 After reacting at 130°C for 6 h, the conversion of HMF was 100.0% and the selectivity of FDCA was 94.7%.

[0128] In summary, when other reaction conditions remain unchanged and only the reaction temperature is changed, the activity is better when the reaction temperature is 130°C, which is the optimal reaction temperature (see Examples 35, 38-40).

[0129] Embodiment 41

[0130] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared Na 2 CO 3 The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 The obtained MnCO 3 The catalyst was calcined at 300°C in a muffle furnace for 2 h to obtain Mn-2 catalyst. 0.1 MPa O 2 0.1 g Mn-2 catalyst, 63 mg HMF, 10 mL H 2 O and 2 equivalents of KHCO 3 After reacting at 120°C for 6 h, the conversion of HMF was 74.4% and the selectivity of FDCA was 11.2%.

[0131] Embodiment 42

[0132] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared Na 2 CO 3 The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 The obtained MnCO 3 The catalyst was calcined at 300°C in a muffle furnace for 2 h to obtain Mn-2 catalyst. 2.0 MPa O 2 0.1 g Mn-2 catalyst, 63 mg HMF, 10 mL H 2 O and 2 equivalents of KHCO 3 After reacting at 120°C for 6 h, the conversion of HMF was 100.0% and the selectivity of FDCA was 96.7%.

[0133] Summary: When other reaction conditions remain unchanged, only the O 2Pressure. The catalytic performance of the catalyst is affected by the O 2 Pressure (0.2-1MPa) is relatively sensitive. When it is higher than 1.0MPa, O 2 The effect of pressure becomes weaker. The activity is better when the reaction pressure is 2.0 MPa, which is the optimal reaction pressure (see Examples 35, 41 and 42).

[0134] Embodiment 43

[0135] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared Na 2 CO 3 The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 The obtained MnCO 3 The catalyst was calcined at 300°C in a muffle furnace for 2 h to obtain Mn-2 catalyst. 1.0 MPa O 2 0.1 g Mn-2 catalyst, 63 mg HMF, 10 mL H 2 O and 2 equivalents of KHCO 3 After reacting at 120°C for 0.5 h, the conversion of HMF was 76.9% and the selectivity of FDCA was 5.8%.

[0136] Embodiment 44

[0137] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared Na 2 CO 3 The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 The obtained MnCO 3 The catalyst was calcined at 300°C in a muffle furnace for 2 h to obtain Mn-2 catalyst. 1.0 MPa O 2 0.1 g Mn-2 catalyst, 63 mg HMF, 10 mL H 2O and 2 equivalents of KHCO 3 After reacting at 120°C for 2 h, the conversion of HMF was 100.0% and the selectivity of FDCA was 34.6%.

[0138] Embodiment 45

[0139] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared Na 2 CO 3 The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 The obtained MnCO 3 The catalyst was calcined at 300°C in a muffle furnace for 2 h to obtain Mn-2 catalyst. 1.0 MPa O 2 0.1 g Mn-2 catalyst, 63 mg HMF, 10 mL H 2 O and 2 equivalents of KHCO 3 After reacting at 120°C for 4 h, the conversion of HMF was 100% and the selectivity of FDCA was 73.9%.

[0140] Embodiment 46

[0141] Dissolve 1.2g of sodium carbonate in 45mL of ultrapure water and mix well by ultrasonication for 5min. 3 ) 2 ·4H 2 O solution 2mL, added dropwise to the prepared Na 2 CO 3 The prepared solution was stirred for 3 hours and aged for 15 minutes. The obtained solution was filtered by vacuum pump and the filter cake was dried in an oven at 80°C for 12 hours to obtain MnCO 3 The obtained MnCO 3 The catalyst was calcined at 300°C in a muffle furnace for 2 h to obtain Mn-2 catalyst. 1.0 MPa O 2 0.1 g Mn-2 catalyst, 63 mg HMF, 10 mL H 2 O and 2 equivalents of KHCO 3 After reacting at 120°C for 6 h, the conversion of HMF was 100% and the selectivity of FDCA was 89.7%.

[0142] In summary, when other reaction conditions remain unchanged and only the reaction time is changed, the conversion rate of HMF changes greatly within 2 hours of reaction and remains at 100% after 2 hours; the selectivity of FDCA increases with the increase of reaction time and the increasing trend slows down after 2 hours of reaction (see Examples 43-46).

[0143] Table 1 Manganese-based heterogeneous catalytic system for the oxidation of HMF to DFF

[0144]

[0145] Note: Production efficiency (mmol·g -1 ·h -1 )=Amount of DFF ÷ Catalyst mass ÷ Reaction time HMF concentration (mmol / L)=Amount of HMF ÷ Volume of DMF

[0146] Table 2 Catalytic activity of HMF oxidation to prepare DFF

[0147]

[0148] Note: Production efficiency (mmol·g -1 ·h -1 )=Amount of DFF ÷ Catalyst mass ÷ Reaction time HMF concentration (mmol / L)=Amount of HMF ÷ Volume of DMF

[0149] Table 3 Catalytic activity of HMF oxidation to prepare DFF

[0150]

[0151] Note: Production efficiency (mmol·g -1 ·h -1 )=Amount of DFF ÷ Catalyst mass ÷ Reaction time HMF concentration (mmol / L)=Amount of HMF ÷ Volume of DMF

[0152] Table 4 Catalytic activity of HMF oxidation to prepare FDCA

[0153]

Claims

1. Application of a composite manganese-based heterogeneous catalyst in catalyzing the selective oxidation of HMF to produce FDCA, characterized in that: HMF, a composite manganese-based heterogeneous catalyst, a magneton, H2O and 2 equivalents of KHCO3 are added into a high-pressure reactor, and reacted for 2 h to 6 h under the conditions of 0.2-2.0 MPa O2, 90-130 °C and the composite manganese-based heterogeneous catalyst to synthesize FDCA; The composite manganese-based heterogeneous catalyst is a catalyst with a molar ratio of MnCO3 crystal form to MnO2 crystal form of 10:90-30:70, prepared by adjusting the calcination conditions using MnCO3 as a precursor. The MnCO3 is prepared from Na2CO3 and Mn(NO3)2·4H2O by a precipitation method. The calcination is carried out in an air muffle furnace, a nitrogen tube furnace or an air tube furnace, and the calcination temperature is 300°C-450°C.

2. The use of the composite manganese-based heterogeneous catalyst according to claim 1 in catalyzing the selective oxidation of HMF to produce FDCA, characterized in that: Dissolve 1.2 g of sodium carbonate in 45 mL of ultrapure water and mix them evenly by ultrasonication for 5 min. Take 2 mL of 50% Mn(NO3)2·4H2O solution and add it dropwise to the prepared sodium carbonate aqueous solution at 600 rpm. Stir the prepared solution for 3 h and age it for 15 min. Filter the obtained solution with a vacuum pump and dry the filter cake in an oven at 80 °C for 12 h to obtain MnCO3. The prepared MnCO3 was heated in a muffle furnace at 2 °C·min -1 The heating rate was maintained at 300 °C for 2 h, and the molar ratio of MnCO3 crystal form to MnO2 crystal form was 31:69, and Mn-2 catalyst was obtained; HMF, Mn-2 catalyst, magneton, H2O and 2 equivalents of KHCO3 are added into a high pressure reactor, and reacted for 2h-6h under the conditions of 0.2-2.0 MPa O2, 90-130 ℃ and a composite manganese-based heterogeneous catalyst to synthesize FDCA.

3. The use of the composite manganese-based heterogeneous catalyst according to claim 2 in catalyzing the selective oxidation of HMF to produce FDCA, characterized in that: 1 MPa O2 was introduced, and 0.15 g Mn-2 catalyst, 63 mg HMF, 10 mL H2O and 2 equivalents of KHCO were added to the autoclave in sequence. 3， After 6 h of reaction at 120 °C, the conversion of HMF was 100.0% and the selectivity of FDCA was 98.3%.

4. Application of a composite manganese-based heterogeneous catalyst in catalyzing the selective oxidation of HMF to DFF, characterized in that: Dissolve 1.2 g of sodium carbonate in 45 mL of ultrapure water, and mix them evenly by ultrasonication for 5 min. Take 2 mL of 50% Mn(NO3)2·4H2O solution and add it dropwise to the prepared sodium carbonate aqueous solution at 600 rpm. Continue stirring the prepared solution for 3 h and age it for 15 min. Filter the obtained solution with a vacuum pump, and dry the filter cake in an oven at 80 °C for 12 h to obtain MnCO3. The prepared MnCO3 was heated in a muffle furnace at 2 °C·min -1 The heating rate was maintained at 300 °C for 2 h, and the molar ratio of MnCO3 crystal form to MnO2 crystal form was 31:69, and Mn-2 catalyst was obtained; HMF, Mn-2 catalyst, magnetron, and N,N-dimethylformamide were added to a three-necked flask at a flow rate of 10 mL min -1 DFF was synthesized by reacting for 15 min-120 min under the conditions of O2, 90-120 ℃ and a composite manganese-based heterogeneous catalyst.

5. The use of the composite manganese-based heterogeneous catalyst according to claim 4 in catalyzing the selective oxidation of HMF to produce DFF, characterized in that: Oxygen was used as the reaction atmosphere at a rate of 10 mL min -1 50 mg Mn-2 catalyst, 129.8 mg HMF and 20 mL DMF were added into a three-hole flask in sequence and reacted at 120 °C for 30 min. The conversion rate was 97.1%, the DFF selectivity was 91.8%, and the production efficiency was 36.7 mmol·g -1 ·h -1 .

6. Use of the composite manganese-based heterogeneous catalyst according to claim 4 in catalyzing the selective oxidation of HMF to produce DFF, characterized in that: Oxygen was used as the reaction atmosphere at a rate of 10 mL min -1 50 mg Mn-2 catalyst, 32 mg HMF and 20 mL DMF were added into the autoclave in sequence and reacted at 120 °C for 30 min. The conversion rate was 97.1%, the DFF selectivity was 96.3%, and the production efficiency was 9.4 mmol·g -1 ·h -1 .

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