Copper-bismuth composite catalyst for formaldehyde acetylation and preparation method thereof

Abstract

A copper-bismuth composite catalyst for the acetyleneation reaction of formaldehyde and its preparation method are disclosed. The method includes: fully dissolving copper nitrate in water and optionally adding polyvinylpyrrolidone and nitric acid to obtain a first solution; fully dissolving bismuth nitrate in nitric acid to obtain a second solution; then fully dissolving sodium carbonate in water to obtain a third solution; simultaneously or sequentially mixing the first and second solutions with the third solution to obtain a precipitate, wherein the molar ratio of copper nitrate, bismuth nitrate, and sodium carbonate during mixing is (15~20):(0.5~1):100; separating and drying the precipitate to obtain the catalyst. The preparation method of this invention is mild and simple, the morphology and size of the obtained catalyst product are controllable, and it exhibits good catalytic performance and is suitable for industrial production.

Description

Technical Field

[0001] This application relates to a copper-bismuth composite catalyst for the acetyleneification reaction of formaldehyde. Background Technology

[0002] 1,4-Butanediol (BDO) is an important chemical raw material, a monomer for synthesizing biodegradable plastics such as polybutylene adipate (PBAT), polybutylene terephthalate (PBT), polybutylene succinate (PBS), and polyurethane (PU), and an important intermediate for the synthesis of tetrahydrofuran (THF) and γ-butyrolactone (GBL). In recent years, BDO has been widely used as a raw material for the synthesis of biodegradable plastics and is an important organic chemical for achieving environmentally friendly alternatives to plastics, thus leading to a significant increase in market demand for BDO. 1,4-Butynediol (BYD) is an important intermediate in the preparation of 1,4-butanediol. Industrial production of 1,4-butanediol mainly employs the Reppe process. The production process first synthesizes BYD from formaldehyde and acetylene in the presence of a copper-based catalyst, and then hydrogenates BYD to 1,4-butanediol. The key to the Reppe process, i.e., the acetylene-formaldehyde reaction, is the copper-bismuth catalyst.

[0003] Existing copper-bismuth catalysts are typically prepared by co-precipitating metal salts followed by high-temperature heat treatment of the precipitate to obtain the corresponding oxides, as disclosed in CN115193440B, CN 120679557A, and CN121402068A. These methods are complex and require high-temperature heat treatment, resulting in uncontrollable morphology and size of the catalysts, leading to low catalytic efficiency and unsuitability for industrial catalytic equipment. Summary of the Invention

[0004] The objective of this invention is to provide at least one copper-bismuth composite catalyst with controllable morphology and size for the formaldehyde acetylene reaction.

[0005] According to a first aspect of the present invention, a method for preparing a copper-bismuth composite catalyst for the formaldehyde acetylene reaction is provided, comprising: The first solution is obtained by fully dissolving copper nitrate in water and optionally adding polyvinylpyrrolidone and nitric acid; Bismuth nitrate is fully dissolved in nitric acid to obtain a second solution; Then, fully dissolve the sodium carbonate in water to obtain a third solution; The first and second solutions are mixed thoroughly with the third solution simultaneously or sequentially to obtain a precipitate. The molar ratio of copper nitrate, bismuth nitrate and sodium carbonate during mixing is (15~20):(0.5~1):100. The catalyst is obtained by separating and drying the precipitate.

[0006] According to a preferred embodiment of the present invention, the concentration of sodium carbonate in the third solution can be 0.9~1 mol / L.

[0007] According to the preparation method of the present invention, it is also preferable to include: heating the mixed solution containing the precipitate at 65°C to 75°C for, for example, more than half an hour before separating the precipitate.

[0008] According to one embodiment of the present invention, the first solution and the second solution can be thoroughly mixed first, and then mixed with the third solution for co-precipitation.

[0009] According to another alternative embodiment of the present invention, the second solution and the third solution may be mixed first for a stepwise precipitation, and then the first solution and the third solution may be mixed for a second stepwise precipitation to obtain a precipitate, wherein the second stepwise precipitation is carried out based on the intermediate precipitate separated from the first stepwise precipitation.

[0010] According to a preferred embodiment of the present invention, the pH value of the mixed solution can be controlled to be 6-7 during mixing.

[0011] According to a preferred embodiment of the present invention, the mass concentration of polyvinylpyrrolidone in the first solution can be 0.8~1.2%.

[0012] According to a preferred embodiment of the present invention, the drying temperature is 65°C to 75°C, for example, for 8 hours or more.

[0013] According to the present invention, mixing can be carried out by parallel flow, forward drop, reverse drop, etc.

[0014] According to another aspect of the present invention, a copper-bismuth composite catalyst for the formaldehyde acetylene reaction prepared according to the above method is also provided, which has a spherical particle morphology with a diameter of 1 to 20 μm.

[0015] The preparation method of the present invention is mild and simple, and the morphology and size of the obtained catalyst product are controllable, with good catalytic performance and suitable for industrial production. Attached Figure Description

[0016] Figure 1a A scanning electron microscope image of the catalyst prepared according to Example 1 of the present invention; Figure 1b Enlarged image of it; Figure 1c The particle size distribution is shown in the diagram.

[0017] Figure 2a A scanning electron microscope image of the catalyst prepared according to Example 2 of the present invention; Figure 2b Enlarged image of it; Figure 2c The particle size distribution is shown in the diagram.

[0018] Figure 3a A scanning electron microscope image of the catalyst prepared according to Example 3 of the present invention; Figure 3b Enlarged image of it; Figure 3c The particle size distribution is shown in the diagram.

[0019] Figure 4a A scanning electron microscope image of the catalyst prepared according to Example 4 of the present invention; Figure 4b Enlarged image of it; Figure 4c The particle size distribution is shown in the diagram.

[0020] Figure 5a A scanning electron microscope image of the catalyst prepared according to Example 5 of the present invention; Figure 5b Enlarged image of it; Figure 5c The particle size distribution is shown in the diagram.

[0021] Figure 6a A scanning electron microscope image of the catalyst prepared according to Example 1 of the present invention; Figure 6b Enlarged image of it; Figure 6c The particle size distribution is shown in the diagram.

[0022] Figure 7 The images show the XRD patterns of the catalysts prepared in Examples 1-6 of this invention. Detailed Implementation

[0023] The present invention will be further explained and illustrated below through specific embodiments.

[0024] Example 1

[0025] Dissolve 8.2 mmol of copper nitrate in a beaker containing 50 mL of deionized water, and dissolve 0.40 mmol of bismuth nitrate in a beaker containing 4 mL of nitric acid (68% by mass; the same below). After complete dissolution, mix the two solutions and stir for 10 min. This solution is labeled as solution A. Prepare 50 mL of 0.95 mol / L sodium carbonate solution and label it solution B. Solution A and solution B were mixed at room temperature and stirred in a uniform, co-current manner to precipitate for 30 minutes, with the pH value controlled at approximately 6.5 by adjusting the flow rate. After precipitation was complete, stirring was stopped, and the mixture was heated at 70°C for 30 minutes. After cooling to room temperature, the mixture was centrifuged, washed, and dried at 70°C for 8 hours to obtain the product.

[0026] Figure 1a Here is a scanning electron microscope image of the product; Figure 1b Enlarged image of it; Figure 1c The particle size distribution is shown in the diagram.

[0027] Example 2

[0028] Dissolve 8.2 mmol of copper nitrate in a beaker containing 50 mL of deionized water, and dissolve 0.40 mmol of bismuth nitrate in a beaker containing 4 mL of nitric acid. After complete dissolution, mix the two solutions and stir for 10 min. This solution is labeled as solution A. Prepare 50 mL of 0.95 mol / L sodium carbonate solution and label it solution B. Solution B was added dropwise to solution A at a uniform rate, and the mixture was stirred to precipitate for 30 minutes. After precipitation was complete, stirring was stopped, and the mixture was heated at 70°C for 30 minutes. After cooling to room temperature, the mixture was centrifuged, washed, and dried at 70°C for 8 hours to obtain the product.

[0029] Figure 2a Here is a scanning electron microscope image of the product; Figure 2b Enlarged image of it; Figure 2c The particle size distribution is shown in the diagram.

[0030] Example 3

[0031] Dissolve 8.2 mmol of copper nitrate in a beaker containing 50 mL of deionized water, and dissolve 0.40 mmol of bismuth nitrate in a beaker containing 2 mL of nitric acid. After complete dissolution, mix the two solutions and stir for 10 min. This solution is labeled as solution A. Prepare 50 mL of 0.95 mol / L sodium carbonate solution and label it solution B. Solution A was added dropwise to solution B at a uniform rate, and the mixture was stirred to precipitate for 30 minutes. After precipitation was complete, stirring was stopped, and the mixture was heated at 70°C for 30 minutes. After cooling to room temperature, the mixture was centrifuged, washed, and dried at 70°C for 8 hours to obtain the product.

[0032] Figure 3a Here is a scanning electron microscope image of the product; Figure 3b Enlarged image of it; Figure 3c The particle size distribution is shown in the diagram.

[0033] Example 4

[0034] Dissolve 8.2 mmol of copper nitrate in a beaker containing 50 mL of deionized water, and dissolve 0.40 mmol of bismuth nitrate in a beaker containing 4 mL of nitric acid. After complete dissolution, mix the two solutions and stir for 10 min. This solution is labeled as solution A. Prepare 50 mL of 0.95 mol / L sodium carbonate solution and label it solution B. Solution A and solution B were mixed uniformly and simultaneously at room temperature under stirring to precipitate for 30 minutes, with the pH value controlled at approximately 6.5 by adjusting the flow rate. After precipitation, stirring was stopped, and the mixture was aged at room temperature for 24 hours, followed by heating at 70°C for 30 minutes. After cooling to room temperature, the mixture was centrifuged, washed, and dried at 70°C for 8 hours to obtain the product.

[0035] Figure 4a Here is a scanning electron microscope image of the product; Figure 4b Enlarged image of it; Figure 4cThe particle size distribution is shown in the diagram.

[0036] Example 5

[0037] Dissolve 8.2 mmol of copper nitrate in 50 mL of deionized water containing 1 wt% polyvinylpyrrolidone (PVP), and dissolve 0.40 mmol of bismuth nitrate in a beaker containing 2 mL of nitric acid. After complete dissolution, mix the two solutions and stir for 10 min. This solution is labeled as solution A. Prepare 50 mL of 0.95 mol / L sodium carbonate solution and label it solution B. Solution A and solution B were mixed at room temperature and stirred in a uniform, co-current manner to precipitate for 30 minutes, with the pH value controlled at approximately 6.5 by adjusting the flow rate. After precipitation was complete, stirring was stopped, and the mixture was heated at 70°C for 30 minutes. After cooling to room temperature, the mixture was centrifuged, washed, and dried at 70°C for 8 hours to obtain the product.

[0038] Figure 5a Here is a scanning electron microscope image of the product; Figure 5b Enlarged image of it; Figure 5c The particle size distribution is shown in the diagram.

[0039] Example 6

[0040] Dissolve 8.2 mmol of copper nitrate in a beaker containing 4 mL of nitric acid and 50 mL of deionized water, and label it solution A; prepare 100 mL of 0.95 mol / L sodium carbonate solution, and label it solution B; dissolve 0.40 mmol of bismuth nitrate in a beaker containing 4 mL of nitric acid and 50 mL of deionized water, and label it solution C after complete dissolution. Take 50 mL of solution B and slowly add it dropwise to solution C. After the addition is complete, stir to precipitate for 1 hour. After centrifugation and washing, transfer the precipitate to an empty beaker. Add 50 mL of solutions A and B dropwise to the beaker containing the precipitate at a uniform flow rate. Stir to precipitate for 30 minutes, controlling the pH value to around 6.5 by adjusting the flow rate. After precipitation is complete, stop stirring and heat at 70℃ for 30 minutes. After cooling to room temperature, centrifuge, wash, and dry at 70℃ for 8 hours to obtain the product.

[0041] Figure 6a Here is a scanning electron microscope image of the product; Figure 6b Enlarged image of it; Figure 6c The particle size distribution is shown in the diagram.

[0042] Figure 7 The figures show the XRD patterns of the catalyst products prepared in Examples 1-6 above. As can be seen from the figures, this invention successfully achieved the controllable preparation of catalyst products with spherical particle morphology having a diameter of 1-20 μm.

[0043] The catalyst products prepared in Examples 1-6 above (corresponding to AF respectively) were tested for formaldehyde acetylene reaction: 1.0 g of the prepared catalyst was weighed into an Erlenmeyer flask containing 20 ml of formaldehyde aqueous solution (37% wt), and reacted for 9 h at atmospheric pressure, 90 °C, and an acetylene flow rate of 30 ml / min. Table 1 shows the evaluation results of each catalyst product.

[0044]

[0045] As shown in Table 1, the catalyst prepared according to the present invention has excellent catalytic effect and can be used for industrial production.

Claims

1. A method for preparing a copper-bismuth composite catalyst for the formaldehyde acetyleneation reaction, comprising: The first solution is obtained by fully dissolving copper nitrate in water and optionally adding polyvinylpyrrolidone and nitric acid; Bismuth nitrate is fully dissolved in nitric acid to obtain a second solution; Then, fully dissolve the sodium carbonate in water to obtain a third solution; The first and second solutions are mixed thoroughly with the third solution simultaneously or sequentially to obtain a precipitate. The molar ratio of copper nitrate, bismuth nitrate and sodium carbonate during mixing is (15~20):(0.5~1):

100. The catalyst is obtained by separating and drying the precipitate.

2. The preparation method according to claim 1, wherein the concentration of sodium carbonate in the third solution is 0.9~1 mol / L.

3. The preparation method according to claim 1 further includes: Before separating the precipitate, the mixed solution containing the precipitate is heated at 65℃~75℃.

4. The preparation method according to claim 1, wherein the first solution and the second solution are first thoroughly mixed and then mixed with the third solution for co-precipitation.

5. The preparation method according to claim 1, wherein the second solution and the third solution are first mixed for a first stepwise precipitation, and then the first solution and the third solution are mixed for a second stepwise precipitation to obtain the precipitate, wherein the second stepwise precipitation is carried out based on the intermediate precipitate separated from the first stepwise precipitation.

6. The preparation method according to claim 1, wherein the pH value of the mixed solution is controlled to be 6-7 during mixing.

7. The preparation method according to claim 1, wherein the mass concentration of polyvinylpyrrolidone in the first solution is 0.8~1.2%.

8. The preparation method according to claim 1, wherein the drying temperature is 65℃~75℃.

9. A copper-bismuth composite catalyst for the formaldehyde acetylene reaction, prepared by the method according to any one of claims 1-8, having a spherical particle morphology with a diameter of 1-20 μm.

Images