A co@zrc catalyst, a preparation method thereof and application thereof in hydrodeoxygenation of furfural compounds

Abstract

The application provides a Co@ZrC catalyst and a preparation method and application thereof in furfural compound hydrogenation deoxygenation, the preparation method is as follows: using fumaric acid and zirconium salt as raw materials, a catalyst precursor Zr-MOF is prepared by a solvothermal synthesis method, then the precursor is impregnated with a cobalt salt, and in-situ high-temperature pyrolysis carbonization reduction is carried out to prepare the Co@ZrC catalyst. The catalyst is used in selective hydrogenation deoxygenation of furfural to prepare 2-methyl furan and selective hydrogenation deoxygenation of 5-hydroxymethyl furfural to prepare 2,5-dimethyl furan, and the target products are obtained in high yield. The catalyst preparation method is simple, the catalyst has high activity and selectivity and good stability, the furfural selective hydrogenation deoxygenation reaction condition is mild, the product yield is high, and obvious industrial production advantages are obtained.

Description

Technical Field

[0001] This invention belongs to the field of catalyst preparation technology, specifically relating to a Co@ZrC catalyst, its preparation method, and its application in the selective hydrogenation and deoxygenation of furfural compounds. Background Technology

[0002] With the dwindling reserves of fossil resources and the increasing severity of environmental pollution, research on the conversion of widely available and inexpensive renewable resources into high-value-added products has received significant attention. Among numerous biomass derivatives, furfural compounds, furfural and 5-hydroxymethylfurfural, are recognized as among the most valuable platform compounds. The selective hydrogenation deoxygenation products of furfural compounds, methylfurans (2-methylfuran and 2,5-dimethylfuran), are widely used in the synthesis of pharmaceuticals, pesticides, and fine chemicals. During the hydrogenation deoxygenation of furfural, side reactions such as furan ring hydrogenation and ring-opening occur simultaneously. Therefore, developing catalysts with excellent catalytic performance plays a crucial role in the selective hydrogenation deoxygenation of furfural compounds.

[0003] CN111905759A discloses a supported bimetallic catalyst (Pd-M / C) for the selective hydrodeoxygenation of furfural to 2-methylfuran. A previous report (Applied Catalysis B: Environment and Energy, 2024, 346: 123719) described a CoAl mixed oxide supported Pd catalyst for the selective hydrodeoxygenation of furfural to 2-methylfuran with a yield of 92.1%. However, the high price of precious metals leads to high production costs. A subsequent report (Journal of Energy Chemistry, 2023, 78: 195-202) reported an N / O co-doped carbon-anchored Co catalyst for the selective hydrodeoxygenation of furfural to 2-methylfuran, achieving 100% furfural conversion and a 94.6% 2-methylfuran yield at 240℃ for 3 h. Currently, non-precious metal catalysts for the hydrodeoxygenation of furfural compounds often require high temperatures and high catalyst dosages, resulting in harsh reaction conditions. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing a non-noble metal catalyst, Co@ZrC, and to use the prepared catalyst in the selective hydrodeoxygenation of furfural to prepare 2-methylfuran and the selective hydrodeoxygenation of 5-hydroxymethylfurfural to prepare 2,5-dimethylfuran. The Co@ZrC catalyst prepared by the method of this invention exhibits high activity, high selectivity, good stability, mild reaction conditions, and high yield.

[0005] To achieve the above experimental objectives, the present invention provides the following solution:

[0006] The preparation method of Co@ZrC catalyst includes the following steps:

[0007] Step 1: Dissolve fumaric acid and Zr salt in a solvent and carry out a solvothermal reaction at 110~180 ℃ for 12~48 h. After cooling, filter and wash, and then dry the washed solid under vacuum at 80-100 ℃ for 8-12 h to obtain the catalyst precursor Zr-MOF-801.

[0008] Step 2: Dissolve the cobalt salt in deionized water, then add the Zr-MOF-801 prepared in Step 1 to the above solution, stir and mix evenly at room temperature, impregnate at room temperature, and vacuum dry at 80-100 ℃ for 8-12 h to obtain the catalyst precursor Co / Zr-MOF-801;

[0009] Step 3: The precursor Co / Zr-MOF-801 is heated and carbonized in situ in an inert gas atmosphere. The large amount of reducing gas released during the carbonization process due to the decomposition of the carbon source is used to reduce the Co salt in the system to Co in situ. 0 The catalyst was then cooled to room temperature to obtain the Co@ZrC catalyst.

[0010] Furthermore, the Zr salt is zirconium chloride or zirconium tetrachloride; the Co salt is cobalt nitrate, cobalt acetate or cobalt chloride; the content of metallic Co in the catalyst is 5~25 wt%, and the mass ratio of Co to Zr is 1:1~5.

[0011] Further, the molar ratio of Zr salt to fumaric acid in step one is 1:0.5~3; the solvent is a mixed solution of N,N-dimethylformamide and formic acid, and the volume ratio of N,N-dimethylformamide to formic acid is 10:1~5.

[0012] Furthermore, the inert gas mentioned in step three is nitrogen, the pyrolysis temperature is 400-900 ℃, and the pyrolysis time is 1-6 h.

[0013] This invention also proposes a Co@ZrC catalyst, wherein the catalyst precursor Co / Zr-MOF-801 is prepared using Zr-MOF-801 as the material, and an in-situ carbonization reduction strategy is adopted to pyrolyze and carbonize Co / Zr-MOF-801 at high temperature, thereby reducing Co metal ions to Co in situ. 0 A porous carbon-embedded Co@ZrC catalyst was obtained.

[0014] The Co@ZrC catalyst prepared in this invention can be well applied in the selective hydrodeoxygenation of furfural to prepare 2-methylfuran and the selective hydrodeoxygenation of 5-hydroxymethylfurfural to prepare 2,5-dimethylfuran. The application method is as follows: using furfural or 5-hydroxymethylfurfural as raw materials, the hydrodeoxygenation reaction is carried out in a high-pressure reactor in a reaction solvent under the action of the Co@ZrC catalyst and a hydrogen atmosphere to prepare 2-methylfuran or 2,5-dimethylfuran. The reaction equation is as follows:

[0015]

[0016] In the formula, the substituent R is hydroxymethyl or hydrogen.

[0017] Furthermore, the mass ratio of the Co@ZrC catalyst to furfural compounds (furfural or 5-hydroxymethylfurfural) is 1:3~10, the reaction temperature is 130~180℃, and the reaction hydrogen pressure is 0.5~3MPa.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] This invention innovatively proposes a simple and effective method for preparing Co@ZrC catalysts, and applies the catalysts to the hydrodeoxygenation of furfural to prepare 2-methylfuran and the selective hydrodeoxygenation of 5-hydroxymethylfurfural to prepare 2,5-dimethylfuran.

[0020] The Co@ZrC catalyst provided by this invention uses non-noble metal Co as the first metal and as the hydrogenation active site, and non-noble metal Zr as the second metal, improving the dispersion and hydrogenation activity of metallic Co. It also utilizes the acid-base properties of ZrO2 to promote the deoxygenation reaction, thereby promoting the formation of the target product. Carbon coating improves the catalyst's stability. The catalyst precursor material Co / Zr-MOF-801 is prepared using Zr-MOF-801 as a support. The porous structure and metal defects of Zr-MOF-801 allow for successful Co loading within the support, improving the dispersion and uniformity of metallic Co and Zr, thus enhancing the catalyst's activity. An in-situ carbonization reduction strategy is employed, using Co / Zr-MOF-801 as the catalyst precursor material, through high-temperature pyrolysis carbonization, to reduce Co metal ions in situ. 0 A porous carbon-embedded Co@ZrC catalyst was obtained.

[0021] The catalyst provided by this invention is low in cost, simple to prepare, economical and effective, highly versatile, highly active, and stable. It can be applied to the process of preparing 2-methylfuran by hydrodeoxygenation of furfural and preparing 2,5-dimethylfuran by selective hydrodeoxygenation of 5-hydroxymethylfurfural. The reaction conditions are mild and environmentally friendly, and the yields of 2-methylfuran and 2,5-dimethylfuran are high with low production costs. Attached Figure Description

[0022] Figure 1 The XRD patterns of Zr-MOF-801, Co / Zr-MOF-801 prepared in this invention, ZrC-700-3h support obtained by pyrolysis, Co@ZrC-700-3h catalyst, and Co@ZrC-700-3h after recycling are compared.

[0023] Figure 2 This is a TEM image of the catalyst Co@ZrC-700-3h prepared in this invention. Detailed Implementation

[0024] The present invention will be further described below with reference to embodiments, but the scope of protection of the present invention is not limited thereto.

[0025] The preparation of Co@ZrC catalyst, taking Co@ZrC-700-3h as an example, is carried out as follows:

[0026] Dissolve 1.45 g (12.5 mmol) of fumaric acid and 4.05 g (12.5 mmol) of ZrOCl2·8H2O in 50 mL N,N The mixture of dimethylformamide and 17.5 mL formic acid was stirred at room temperature for 30 min, then transferred to a hydrothermal synthesis reactor and maintained at 120 °C for 24 h. After hydrothermal synthesis, the mixture was allowed to cool naturally to room temperature, the reactor was disassembled, and the precipitate was collected by centrifugation. N,N The sample was washed three times with dimethylformamide and then three times with methanol. The solid was then vacuum-dried at 110 °C for 12 h to obtain a white solid powder, Zr-MOF-801. 0.484 g of Co(NO3)2·6H2O was weighed and dissolved in deionized water. A certain amount of the dried Zr-MOF-801 support was then added to the solution, stirred and mixed thoroughly at room temperature, and impregnated at room temperature for 24 h. The mixture was then dried at 100 °C for 10 h to obtain Co / Zr-MOF-801. This was placed in a tubular calcination furnace and calcined at 700 °C for 3 h under a nitrogen atmosphere to obtain the catalyst Co@ZrC-700-3h.

[0027] Following the same method described above, different Co@ZrC catalysts were prepared by changing the calcination temperature or calcination time of Co / Zr-MOF-801. These catalysts were named Co@ZrC-AB, where A is the calcination temperature and B is the calcination time.

[0028] The XRD pattern of the catalyst prepared in this invention is as follows: Figure 1As shown: characteristic peaks of Zr-MOF-801 were observed at 8.5°, 9.8°, and 30.7° on the unpyrolyzed catalyst, indicating that the support was a successfully prepared Zr-MOF-801 material. In the catalyst after pyrolysis at 700℃, the characteristic diffraction peaks of Zr-MOF-801 disappeared, and the strong peaks at 30.3°, 50.4°, and 60.0° appeared as characteristic diffraction peaks of ZrO2, indicating that the structure formed by the self-assembly of the central Zr metal ion and the organic ligand fumaric acid was destroyed after pyrolysis, and ZrO2 was generated. The diffraction peaks of Co@ZrC-700-3h catalyst at 2θ = 44.2°, 52.2°, and 75.8° correspond to the (111), (200), and (220) planes of Co, respectively, and the two weak peaks at 35.6° and 63.0° belong to the (111) and (220) diffraction peaks of CoO. The diffraction peaks of Co are relatively broad, which indicates that Co grains are small.

[0029] The TEM spectrum of the Co@ZrC catalyst prepared in this invention is as follows: Figure 2 As shown: TEM images reveal the presence of highly dispersed Co NPs on the Co@ZrC catalyst. Example 1

[0030] 0.30 g (3 mmol) of furfural, 60 mg of Co@ZrC-700-3h catalyst, and 5 mL of isopropanol were added to a 25 mL high-pressure reactor. The reactor was sealed, purged five times with nitrogen, and pressurized to 1.0 MPa with H2. The reaction temperature was 170 °C, and the reaction time was 4 h. The furfural conversion rate was 100%, and the 2-methylfuran yield was 96.5%. Example 2

[0031] 0.30 g (3 mmol) of furfural, 60 mg of Co@ZrC-550-4h catalyst, and 5 mL of isopropanol were added to a 25 mL high-pressure reactor. The reactor was sealed, purged five times with nitrogen, and pressurized to 1.0 MPa with H2. The reaction temperature was 170 °C, and the reaction time was 6 h. The furfural conversion rate was 100%, and the 2-methylfuran yield was 95.8%. Example 3

[0032] 0.30 g (3 mmol) of furfural, 30 mg of Co@ZrC-550-4h catalyst, and 5 mL of isopropanol were added to a 25 mL high-pressure reactor. The reactor was sealed, purged five times with nitrogen, and pressurized to 1.0 MPa with H2. The reaction temperature was 170 °C, and the reaction time was 6 h. The furfural conversion rate was 100%, and the 2-methylfuran yield was 81.1%. Example 4

[0033] 0.30 g (3 mmol) of furfural, 60 mg of Co@ZrC-550-4h catalyst, and 5 mL of tetrahydrofuran were added to a 25 mL high-pressure reactor. The reactor was sealed, purged five times with nitrogen, and pressurized to 1.0 MPa with H2. The reaction was carried out at 170 °C for 5 h, resulting in a 100% conversion of furfural and a 85.0% yield of 2-methylfuran. Example 5

[0034] 0.30 g (3 mmol) of furfural, 60 mg of Co@ZrC-700-2h catalyst, and 5 mL of isopropanol were added to a 25 mL high-pressure reactor. The reactor was sealed, purged five times with nitrogen, and pressurized to 1.0 MPa with H2. The reaction temperature was 170 ℃, and the reaction time was 5 h. The furfural conversion rate was 100%, and the 2-methylfuran yield was 85.2%. Example 6

[0035] 0.38 g (3 mmol) of 5-hydroxymethylfurfural, 60 mg of Co@ZrC-700-3h catalyst, and 5 mL of tetrahydrofuran were added to a 25 mL high-pressure reactor. The reactor was sealed, purged five times with nitrogen, and pressurized to 1.0 MPa with H2. The reaction was carried out at 150 °C for 8 h. The conversion rate of 5-hydroxymethylfurfural was 100%, and the yield of 2,5-dimethylfuran was 90.7%. Example 7

[0036] 0.38 g (3 mmol) of 5-hydroxymethylfurfural, 50 mg of Co@ZrC-700-3h catalyst, and 5 mL of tetrahydrofuran were added to a 25 mL high-pressure reactor. The reactor was sealed, purged five times with nitrogen, and pressurized to 1.0 MPa with H2. The reaction temperature was 150 °C, and the reaction time was 8 h. The conversion rate of 5-hydroxymethylfurfural was 100%, and the yield of 2,5-dimethylfuran was 96.8%. Example 8

[0037] 0.38 g (3 mmol) of 5-hydroxymethylfurfural, 60 mg of Co@ZrC-700-3h catalyst, and 5 mL of water were added to a 25 mL high-pressure reactor. The reactor was sealed, purged five times with nitrogen, and pressurized to 1.0 MPa with H2. The reaction temperature was 150 °C, and the reaction was carried out for 10 h. The conversion rate of 5-hydroxymethylfurfural was 100%, and the yield of 2,5-dimethylfuran was 71.2%. Example 9

[0038] 0.38 g (3 mmol) of 5-hydroxymethylfurfural, 50 mg of Co@ZrC-700-3h catalyst, and 5 mL of tetrahydrofuran were added to a 25 mL high-pressure reactor. The reactor was sealed, purged five times with nitrogen, and pressurized to 1.0 MPa with H2. The reaction was carried out at 170 °C for 4 h. The conversion rate of 5-hydroxymethylfurfural was 100%, and the yield of 2,5-dimethylfuran was 79.8%.

[0039] Examples 10-17

[0040] Other operations are the same as in Example 1, except that the number of times the catalyst is recycled is changed (after each reaction, the catalyst is centrifuged and recycled for reuse), and the following reaction results are obtained (Table 1):

[0041] Table 1

[0042]

[0043] In summary, this patent introduces a Co@ZrC catalyst, its preparation method, and its application in the hydrodeoxygenation of furfural compounds. The catalyst precursor Zr-MOF is prepared by solvothermal synthesis, followed by cobalt salt impregnation and in-situ high-temperature pyrolysis carbonization reduction to obtain the Co@ZrC catalyst. This catalyst was used for the selective hydrodeoxygenation of furfural to 2-methylfuran and the selective hydrodeoxygenation of 5-hydroxymethylfurfural to 2,5-dimethylfuran, both yielding the target products in high yields.

Claims

1. Use of a catalyst for the production of furanic compounds by hydrodeoxygenation of furfural compounds, characterized in that, The catalyst is prepared by taking Zr-MOF-801 as a material to prepare a catalyst precursor Co / Zr-MOF-801, and adopting an in-situ carbonization reduction strategy to pyrolyze and carbonize Co / Zr-MOF-801 at high temperature, so that Co metal ions are in-situ reduced to Co 0 , and a porous carbon-embedded catalyst is obtained. The preparation method of the catalyst comprises the following steps: Step 1: Dissolve fumaric acid and Zr salt in a solvent and carry out a solvothermal reaction at 110~180 ℃ for 12~48 h. After cooling, filter and wash, and then dry the washed solid under vacuum at 80-100 ℃ for 8-12 h to obtain the catalyst precursor Zr-MOF-801. Step 2: Dissolve the cobalt salt in deionized water, then add the Zr-MOF-801 prepared in Step 1 to the above solution, stir and mix evenly at room temperature, impregnate at room temperature, and vacuum dry at 80-100 ℃ for 8-12 h to obtain the catalyst precursor Co / Zr-MOF-801; Step three: the above precursor Co / Zr-MOF-801 prepared in step two is heated to pyrolysis and in-situ carbonization in an inert gas atmosphere, and the Co salt in the system is in-situ reduced to Co by a large amount of reducing gas released in the carbonization process due to the decomposition of the carbon source 0 , and cooled to room temperature to obtain the catalyst; The Zr salt is zirconium chloride or zirconium tetrachloride; the Co salt is cobalt nitrate, cobalt acetate or cobalt chloride; the content of metallic Co in the catalyst is 5~25 wt%, and the mass ratio of Co to Zr is 1:1~5; The pyrolysis temperature in step three is 400-900 ℃, and the pyrolysis time is 1-6 h.

2. The use of the catalyst according to claim 1 in the production of furan compounds by hydrodeoxygenation of furfural compounds, characterized in that, The molar ratio of Zr salt to fumaric acid in step one is 1:0.5~3; the solvent is a mixed solution of N,N-dimethylformamide and formic acid, and the volume ratio of N,N-dimethylformamide to formic acid is 10:1~5.

3. The use of the catalyst according to claim 1 in the production of furan compounds by hydrodeoxygenation of furfural compounds, characterized in that, The catalysts are applied to the selective hydrogenation and deoxygenation of furfural to prepare 2-methylfuran and the selective hydrogenation and deoxygenation of 5-hydroxymethylfurfural to prepare 2,5-dimethylfuran, respectively. The application method is as follows: using furfural or 5-hydroxymethylfurfural as raw materials, the hydrogenation and deoxygenation reaction is carried out in a high-pressure reactor, in a reaction solvent, under the action of the catalyst, and in a hydrogen atmosphere to prepare 2-methylfuran or 2,5-dimethylfuran.

4. The application of the catalyst according to claim 1 in the preparation of furan compounds by hydrogenation and deoxygenation of furfural compounds, characterized in that, The mass ratio of the catalyst to furfural compounds is 1:3~10, the reaction temperature is 130~180℃, and the reaction hydrogen pressure is 0.5~3MPa.

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