Preparation method of graded multi-site basic copper carbonate and chromium carbonate
By introducing strong ultrasonic assisted and in-situ mixed alkaline chromium carbonate during the crystal nucleation process, a multi-site basic copper carbonate catalyst was prepared, which solved the problem of few active sites of the existing basic copper carbonate catalyst, and achieved a high conversion rate and high selectivity acetylene and formaldehyde addition reaction.
Patent Information
- Application Number
- CN202510378201.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-28
- Publication Date
- 2025-07-18
AI Technical Summary
The existing basic copper carbonate catalyst has a single structure and few active sites, which leads to low conversion rate of acetylene and formaldehyde addition reactions and low selectivity of 1,4-butyne glycol and many by-products.
In the process of crystal nucleation, strong ultrasonic assistance is introduced to perform secondary nucleation and growth, forming a hierarchical structure, and in situ mixing alkali chromium carbonate and alkali copper carbonate at the atomic lattice level to form a multi-site catalyst.
The surfactant sites of the catalyst are improved, the generation of by-products is inhibited, the reaction conversion rate and target product selectivity are improved, and the process is simple and easy to industrialize.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention belongs to the field of industrial catalysis, and particularly relates to a preparation method of hierarchical multi-site basic copper carbonate and chromium for addition reactions. Background Art
[0002] As an important industrial raw material, 1,4-butynediol can be used to produce polyurethane foams for building insulation, manufacture high-performance coatings and resins; it can be used to synthesize precursors of antibiotics, antiviral drugs, and hormonal drugs; and it can be used to synthesize pesticides, fungicides, herbicides, and chemicals for promoting plant growth (such as gibberellin, etc.); it can also be used to manufacture surfactants, which can be used in detergents, cleaners, and emulsifiers; used to manufacture plasticizers in certain products to improve their flexibility and processing performance; in addition, it can be used to manufacture electronic components and materials, such as conductive polymers; it can be used to synthesize finishing agents and dyes for textiles. Obtaining 1,4-butynediol through the addition reaction of acetylene and formaldehyde is one of the main methods used in industrial production. The main catalyst used in this addition reaction is basic copper carbonate, and its properties (such as composition, particle size, morphology, etc.) have a great influence on the conversion rate and product selectivity of the reaction.
[0003] At present, there have been various reports on the preparation methods of basic copper carbonate, and their structures and morphologies are also different, such as hollow spheres, solid spheres, ellipsoids, etc. However, the basic copper carbonate catalysts synthesized by previous methods generally show single components, relatively uniform structures, and smooth and closed surfaces, resulting in fewer overall active sites of the catalyst and insufficient effective contact with the reactants acetylene and formaldehyde, resulting in low conversion rates of the addition reaction and low selectivity of 1,4-butynediol (more by-products). Exploring new process methods and component designs to effectively regulate the nucleation and growth processes of crystals, obtaining catalysts with hierarchical structures and rich sites, and simultaneously in-situ introducing a second phase - basic chromium carbonate to mix with basic copper carbonate at the atomic lattice level. This can not only increase the surface active sites of the catalyst but also effectively inhibit the generation of by-products in the addition reaction, thereby improving the conversion rate of the reaction and the selectivity of the target product. Summary of the Invention
[0004] In order to overcome the deficiencies of the prior art, the purpose of the present invention is to provide a preparation method of hierarchical multi-site basic copper carbonate and chromium for addition reactions.
[0005] The preparation method of hierarchical multi-site basic copper carbonate and chromium provided by the present invention includes the following steps:
[0006] Step 1: Simultaneously drop aqueous copper salt solution A, aqueous chromium salt solution A, and aqueous sodium carbonate solution A into the reaction kettle. During the dropping process, the temperature inside the reaction kettle is 35 - 55°C, and stir while dropping; during dropping, the pH of the mixed solution is controlled at 6.5 - 8.5; the mass percentage concentration of the aqueous copper salt solution A is 46% - 52%, the mass percentage concentration of the aqueous chromium salt solution A is 2% - 6%, and the mass percentage concentration of the aqueous sodium carbonate solution A is 25% - 29%; and the volume of the aqueous chromium salt solution A is the same as that of the aqueous copper salt solution A.
[0007] Step 2: Let the mixed solution obtained in Step 1 stand still and then perform ultrasonic treatment with an ultrasonic cell disruptor, with the ultrasonic power being 150 - 250 W.
[0008] Step 3: Simultaneously drop aqueous copper salt solution B, aqueous chromium salt solution B, and aqueous sodium carbonate solution B into the reaction solution obtained in Step 2, stir while dropping, and the temperature inside the reaction kettle and the pH of the mixed solution during dropping are the same as those in Step 1; the mass percentage concentration of the aqueous copper salt solution B is the same as that of the aqueous copper salt solution A, the mass percentage concentration of the aqueous chromium salt solution B is the same as that of the aqueous chromium salt solution A, and the mass percentage concentration of the aqueous sodium carbonate solution B is the same as that of the aqueous sodium carbonate solution A; and the volume of the aqueous chromium salt solution B is the same as that of the aqueous copper salt solution B.
[0009] Step 4: Filter the mixed solution obtained in Step 3, collect the solid product, wash it until it is neutral, and then dry it to obtain basic copper carbonate.
[0010] An optional solution is that the copper salt is selected from copper nitrate, copper sulfate, or copper chloride.
[0011] An optional solution is that the chromium salt is selected from chromium nitrate.
[0012] An optional solution is that in Step 2, ultrasonic treatment is carried out until the color of the solution gradually changes from the initial sky blue to blue - green.
[0013] An optional solution is that the ultrasonic treatment duration in Step 2 is 10 - 30 min.
[0014] An optional solution is that in Step 4, ultrapure water is used to wash the solid product.
[0015] An optional solution is that the drying temperature in Step 4 is 80 - 120°C.
[0016] In the present invention, basic chromium carbonate, as the second phase, is in - situ introduced from the beginning of the reaction, enabling it to achieve uniform chemical mixing with basic copper carbonate at the atomic lattice level. Different from the previous physical mixing, it can effectively inhibit the generation of by - products and improve the selectivity of the target product 1,4 - butynediol when applied to the production of 1,4 - butynediol.
[0017] In addition, in the crystal nucleation process of the present invention, powerful ultrasonic assistance is introduced to locally break and reorganize the crystals that have nucleated and grown, realizing secondary nucleation and re-growth of the crystals, thereby obtaining basic copper carbonate and chromium with a hierarchical structure and multiple sites, increasing the exposed area and active sites of the catalyst, and effectively improving the reaction conversion rate. Moreover, the process of the present invention is simple, easy to realize industrial automation, low-cost, and has high repeatability; the obtained catalyst has high stability and high catalytic activity. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 It is the SEM image of the sample prepared in Example 1.
[0019] Figure 2 It is the XRD pattern of the sample prepared in Example 1.
[0020] Figure 3 It is the SEM image of the sample prepared in Example 2.
[0021] Figure 4 It is the XRD pattern of the sample prepared in Example 2.
[0022] Figure 5 It is the SEM image of the sample prepared in Comparative Example 1.
[0023] Figure 6 It is the XRD pattern of the sample prepared in Comparative Example 1. DETAILED DESCRIPTION OF THE INVENTION
[0024] Unless otherwise specified, scientific and technical terms in this article are understood according to the knowledge of those of ordinary skill in the relevant fields.
[0025] The present invention will be further described in detail below with reference to specific examples and drawings, but the specific examples do not limit the present invention in any way. The materials, methods, solution concentrations, and examples described below are merely exemplary and are not intended to be limiting. In a specific embodiment, those skilled in the art can optimize the operation parameters such as specific substances, substance ratios, concentrations, temperatures, reaction durations, etc. involved in the method by using conventional experimental methods according to the content disclosed in the present invention to achieve the purpose of the present invention. Unless otherwise specified, the raw materials and reagents involved in the specific examples are commercially available products.
[0026] Example 1:
[0027] The reaction raw materials used in this example are:
[0028] At room temperature, two portions of 138 g of copper nitrate were weighed respectively and dispersed into two beakers containing 162 mL of water, stirred and dissolved to prepare two copper nitrate aqueous solutions with a mass fraction of 46%, which were used as copper nitrate aqueous solution A and B respectively;
[0029] Weigh two portions of 6 g of chromium nitrate respectively, and disperse them into two beakers containing 294 mL of water respectively. Stir to dissolve them to prepare two chromium nitrate aqueous solutions with a mass fraction of 2%, which are used as chromium nitrate aqueous solutions A and B respectively.
[0030] Weigh two portions of 100 g of sodium carbonate respectively, and add them into two beakers containing 300 mL of water respectively. Stir to dissolve them to prepare two sodium carbonate aqueous solutions with a mass fraction of 25%, which are used as sodium carbonate aqueous solutions A and B respectively.
[0031] The specific preparation method of this example is as follows:
[0032] Step 1: Simultaneously drip copper nitrate solution A, chromium nitrate solution A, and sodium carbonate solution A into the reaction kettle. Set the heating temperature of the reaction kettle to 35 °C, set the stirring speed at 250 r / min, and control the dropping of the three solutions to be completed within 60 min. Control the pH of the mixed solution during dropping to be about 7.0.
[0033] Step 2: Let the mixed solution after dropping stand for 50 min, and then use an ultrasonic cell disruptor (LD-CP1000) to perform ultrasonic treatment on the mixed solution. Control the power at 200 W. After 15 min of ultrasonic treatment, the color of the reaction solution changes from the initial sky blue to blue-green.
[0034] Step 3: Simultaneously drip copper nitrate solution B, chromium nitrate solution B, and sodium carbonate solution B into the reaction solution obtained in Step 2. The reaction temperature, stirring speed, solution dropping duration, and pH are the same as those in Step 1.
[0035] Step 4: Filter the mixed solution obtained in Step 3, collect the solid product, and wash it repeatedly with ultrapure water until the washing solution is neutral. Then dry it at 100 ± 10 °C, and finally obtain a hierarchical multi-site basic copper carbonate and chromium blue-green powder.
[0036] Figure 1 SEM images of the hierarchical multi-site basic copper carbonate and chromium in the product of Example 1, from Figure 1 It can be seen that the microscopic morphology of the obtained product is composed of micron spheres and particles (hierarchical) of various sizes stacked together. Among them, the diameter of the larger micron spheres is 15 - 20 μm, and the size of the smaller micron spheres or particles is 0.5 - 4 μm. This is due to the secondary nucleation process caused by ultrasonic assistance, with a rough surface, forming a hierarchical structure and rich surface active sites, which is beneficial to the addition reaction.
[0037] Figure 2XRD pattern of the product of Example 1. The crystal diffraction peaks of the solid product match the standard card pattern of basic copper carbonate (JCPDS No. 76-0660), and no separate diffraction peaks of basic chromium carbonate appear. The main reason is that the content of basic chromium carbonate is relatively low, and its diffraction peaks overlap with those of basic copper carbonate and thus are not visible, indicating that chromium elements are incorporated into the lattice of basic copper carbonate in the form of basic chromium carbonate in situ during the chemical reaction. In addition, the overall crystallinity of the catalyst is good, so the product of the present invention is named basic copper, chromium carbonate.
[0038] Example 2:
[0039] The difference between this example and Example 1 is as follows:
[0040] Its preparation raw materials are: at room temperature, two portions of 156 g of copper sulfate are weighed respectively and dispersed into two beakers containing 144 mL of water, stirred and dissolved to prepare two copper sulfate aqueous solutions with a mass fraction of 52%;
[0041] Two portions of 9 g of chromium nitrate are weighed respectively and dispersed into two beakers containing 291 mL of water, stirred and dissolved to prepare two chromium nitrate aqueous solutions with a mass fraction of 3%;
[0042] Two portions of 104 g of sodium carbonate are weighed respectively and added to two beakers containing 296 mL of water, stirred and dissolved to prepare two sodium carbonate aqueous solutions with a mass fraction of 26%;
[0043] In addition, in step 1, the heating temperature of the reaction kettle is set at 45 °C, the stirring speed is set at 320 r / min, and the pH of the mixed solution is set at about 7.6;
[0044] In step 2, it is left to stand for 80 min, the ultrasonic power is controlled at 250 W, and ultrasonic treatment is carried out for 20 min;
[0045] In step 4, it is dried at 95 ± 10 °C, and finally a hierarchical multi-site basic copper, chromium carbonate blue-green powder is obtained.
[0046] Figure 3 SEM image of the hierarchical multi-site basic copper, chromium carbonate of the product of Example 2. From Figure 3 It can be seen that the microscopic morphology of the obtained product is still composed of micron-sized spheres and particles of various sizes (hierarchical) stacked together. Among them, the diameter of the larger micron-sized spheres is 8-12 μm, and the size of the smaller micron-sized spheres or particles is 0.5-5 μm, which results from the secondary nucleation process caused by ultrasonic assistance. The surface is rough, forming a hierarchical structure and rich surface active sites, which is beneficial to the addition reaction.
[0047] Figure 4XRD pattern of the product of Example 2. The crystal diffraction peak pattern of the solid product matches the standard card pattern of basic copper carbonate (JCPDS No. 76-0660). There is no separate diffraction peak of basic chromium carbonate. The main reason is that the content of basic chromium carbonate is relatively low, and its diffraction peak coincides with that of basic copper carbonate and thus does not appear, indicating that chromium element is in-situ incorporated into the lattice of basic copper carbonate in the form of basic chromium carbonate during the chemical reaction process; in addition, the overall crystallinity of the catalyst is good.
[0048] Comparative Example 1:
[0049] The difference between this comparative example and Example 1 is that chromium nitrate is not introduced in Steps 1 and 3, and high-intensity ultrasound is not used in Step 2. The specific steps are as follows:
[0050] Step 1: Simultaneously add copper nitrate solution A and sodium carbonate solution A to the reaction kettle. The heating temperature of the reaction kettle is set at 35 °C, the stirring speed is set at 250 r / min, and the pH of the mixed solution is set at about 7.0.
[0051] Step 2: After the solution is added, let it stand for 50 min, and the color of the solution gradually changes from the initial sky blue to green.
[0052] Step 3: Simultaneously add copper nitrate solution B and sodium carbonate solution B to the reaction solution obtained in Step 2. The reaction temperature, stirring speed, solution addition duration, and pH are the same as those in Step 1.
[0053] Step 4: Filter the mixed solution obtained in Step 3, collect the solid product, wash it repeatedly with ultrapure water until the washing solution is neutral, then dry it at 100 ± 10 °C, and finally obtain a hierarchical multi-site basic copper carbonate and chromium blue-green powder.
[0054] Figure 5 SEM image of the basic copper carbonate product of Comparative Example 1. It can be seen from this figure that the microscopic morphology of the obtained basic copper carbonate is a solid spherical shape with a diameter of 10-15 μm and a smooth and closed surface. Figure 6 XRD pattern of the product of Comparative Example 1. The crystal diffraction peak pattern of the solid product matches the standard card pattern of basic copper carbonate (JCPDS No. 76-0660).
[0055] Comparative Example 2:
[0056] The difference between this comparative example and Example 1 is that high-intensity ultrasound is not used in Step 2, that is, after the solution is added and let it stand for 50 min, and the color of the solution gradually changes from the initial sky blue to green, then Step 3 is carried out.
[0057] Comparative Example 3:
[0058] The difference between this comparative example and Example 1 is that chromium nitrate is not introduced in Steps 1 and 3.
[0059] The solid catalyst powder obtained from the above Examples 1-2 and Comparative Examples 1-3 was further used for the addition catalytic reaction to prepare 1,4-butynediol by adding formaldehyde and acetylene. The specific method was as follows:
[0060] In a reaction kettle, 25 g of catalyst powder and 40 mL of water were added and stirred to form a suspension. Formaldehyde and acetylene were respectively introduced into the reaction kettle. The concentration range of acetylene was controlled at 35%, the concentration range of formaldehyde was controlled at 45%, the pH in the reaction kettle was controlled at 7.0, the internal pressure of the reaction kettle was controlled at 45 KPa, the reaction temperature was controlled at 65 °C, and the reaction was carried out for 72 hours.
[0061] After identification, the obtained product was 1,4-butynediol. The remaining concentration of formaldehyde and the concentration of 1,4-butynediol were respectively detected by chromatography, and then the reaction conversion rate and the selectivity of the target product 1,4-butynediol were calculated. The test results are shown in Table 1.
[0062] Table 1
[0063] Sample Reaction conversion rate / % 1,4-Butynediol selectivity / % 1,4-Butynediol yield / % Example 1 99.5％ 99.0％ 98.5％ Example 2 98.9％ 99.2％ 98.1％ Comparative Example 1 78.5％ 76.0％ 59.7％ Comparative Example 2 85.6％ 80.1％ 68.6％ Comparative Example 3 89.2％ 81.6％ 72.8％
[0064] It can be seen from the test data in Table 1 that the hierarchical multi-site basic copper carbonate and chromium (Examples 1-2) prepared by the method of the present invention have extremely high catalytic activity and product selectivity in the catalytic addition reaction of acetylene and formaldehyde. However, the catalytic activities and selectivities of Comparative Examples 1-3 (without using high-power ultrasound or / and without introducing basic chromium carbonate) are relatively low. Moreover, the product structure obtained in Comparative Example 1 without using high-power ultrasound and without introducing basic chromium carbonate is a closed solid sphere. It can be seen that when the catalyst was prepared in the present invention, high-power ultrasound assistance was innovatively introduced during the crystal nucleation process to realize secondary nucleation and growth of the crystal, forming a hierarchical structure and rich surface active sites. At the same time, the second phase of basic chromium carbonate was in-situ introduced to achieve uniform chemical mixing with basic copper carbonate at the atomic lattice level, inhibiting the generation of by-products, and thus showing excellent reaction conversion rate and product selectivity in the catalytic addition reaction.
Claims
1. A preparation method of hierarchical multi-site basic copper carbonate and chromium, characterized in that, It includes the following steps: Step 1: Simultaneously drop aqueous copper salt solution A, aqueous chromium salt solution A, and aqueous sodium carbonate solution A into the reaction kettle. During the dropping process, the temperature in the reaction kettle is 35 - 55°C, and it is stirred while dropping; the pH of the mixed solution during dropping is controlled at 6.5 - 8.5; the mass percentage concentration of the aqueous copper salt solution A is 46% - 52%, the mass percentage concentration of the aqueous chromium salt solution A is 2% - 6%, and the mass percentage concentration of the aqueous sodium carbonate solution A is 25% - 29%; and the volume of the aqueous chromium salt solution A is the same as that of the aqueous copper salt solution A. Step 2: Let the mixed solution obtained in Step 1 stand still and then perform ultrasonic treatment with an ultrasonic cell disruptor, and the ultrasonic power is 150 - 250 W. Step 3: Simultaneously drop aqueous copper salt solution B, aqueous chromium salt solution B, and aqueous sodium carbonate solution B into the reaction solution obtained in Step 2, stir while dropping, and the temperature in the reaction kettle and the pH of the mixed solution during dropping are the same as those in Step 1; the mass percentage concentration of the aqueous copper salt solution B is the same as that of the aqueous copper salt solution A, the mass percentage concentration of the aqueous chromium salt solution B is the same as that of the aqueous chromium salt solution A, and the mass percentage concentration of the aqueous sodium carbonate solution B is the same as that of the aqueous sodium carbonate solution A; and the volume of the aqueous chromium salt solution B is the same as that of the aqueous copper salt solution B. Step 4: Filter the mixed solution obtained in Step 3, collect the solid product, wash it until it is neutral, and then dry it to obtain basic copper carbonate.
2. The preparation method of the hierarchical multi-site basic copper carbonate and chromium according to claim 1, characterized in that, The copper salt is selected from copper nitrate, copper sulfate, or copper chloride.
3. The preparation method of the hierarchical multi-site basic copper carbonate and chromium according to claim 1, characterized in that, The chromium salt is selected from chromium nitrate.
4. The preparation method of the hierarchically multi-site basic copper carbonate and chromium according to claim 1, characterized in that, In Step 2, the ultrasonic treatment is carried out until the color of the solution gradually changes from the initial sky blue to blue - green.
5. The preparation method of the hierarchically multi-site basic copper carbonate and chromium according to claim 1, wherein, The ultrasonic treatment duration in Step 2 is 10 - 30 min.
6. The preparation method of the hierarchical multi-site basic copper carbonate and chromium according to claim 1, characterized in that, In Step 4, ultrapure water is used to wash the solid product.
7. The preparation method of the hierarchical multi-site basic copper carbonate and chromium according to claim 1, characterized in that, The drying temperature in Step 4 is 80 - 120°C.
8. Application of basic copper carbonate prepared by the method according to any one of claims 1 - 7 and chromium as a catalyst for the reaction of acetylene and formaldehyde to prepare 1,4 - butynediol.