Copper-based solid catalyst with controllable phase interface as well as preparation method and application of copper-based solid catalyst

Abstract

The invention discloses a phase interface controllable copper-based solid catalyst and a preparation method and application thereof, and belongs to the technical field of catalyst preparation and catalytic reaction engineering. According to the copper-based solid catalyst, metal salts are used as a copper source, a bismuth source and a manganese source, a bidentate complexing agent containing a C element is used as a guiding agent, the metal salts and the complexing agent are mixed and then self-assembled in advance in a solution to form a coordination complex, and then the coordination complex is dried and roasted to obtain the copper-based solid catalyst. The outer layer of the copper-based solid catalyst is a porous carbon shell layer with controllable hydrophilicity and hydrophobicity and thickness, and a copper center coordination site is coated and limited by a carbon layer; the outer layer of the active copper center of the copper-based solid catalyst is coated with a porous carbon shell layer with controllable gas-liquid-solid three-phase interface activity, so that hydration of a silicon-based carrier of an industrial catalyst in a water-phase reaction system can be overcome, and the stability of the catalyst is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalyst preparation and catalytic reaction engineering, and specifically relates to a copper-based solid catalyst with controllable phase interface, a preparation method and an application thereof. Background Art

[0002] Propargyl alcohol and 1,4-butynediol, synthesized catalytically from coal-based primary chemicals formaldehyde and acetylene, possess both an electron-rich -C≡C- group and a polar -OH group. Propargyl alcohol is primarily used in pharmaceutical intermediates, agricultural chemicals, and electroplating corrosion protection. 1,4-Butynediol, on the other hand, serves as an important chemical raw material, potentially enabling downstream production of a range of high-value-added chemicals used in various areas of national economy and people's livelihoods. In recent years, with the simultaneous expansion of production and product categories of proppargyl alcohol, 1,4-butynediol, and their downstream high-value-added chemicals, the acetylene-aldehyde process for producing acetylenic alcohols has become a key industry chain for the efficient and comprehensive utilization of coal-based resources. Industrially, to address the difficulty in controlling the selectivity of butynediol and proppargyl alcohol, strategies have been employed to alter the ratio of the reactants acetylene to formaldehyde. These strategies include pressurizing the acetylene while diluting the formaldehyde solution or adding organic solvents with high acetylene solubility to the formaldehyde solution. This approach alters product selectivity, increasing the yield of proppargyl alcohol while decreasing the yield of butynediol, thereby affecting the distribution of the reaction products. In actual production, this method is highly susceptible to explosion accidents and side reactions, and the introduction of organic solvents complicates the product separation and purification process. Furthermore, the silica catalyst carrier used is easily hydrated in the reaction system, causing the catalyst structure to collapse and resulting in poor catalyst stability.

[0003] The invention patent (CN 113751039 A) utilizes a silane reagent to modify the catalyst surface, achieving a modest improvement in selectivity for propargyl alcohol. However, the catalyst surface modification process is cumbersome, and the post-modified silane molecules have very limited binding to the catalyst surface, easily falling off during prolonged alkynol synthesis reactions, affecting catalyst stability. The introduction of the precious metal Au component into the catalyst system increases costs, hindering industrial application. Therefore, the design and preparation of a stable and efficient catalyst with controllable selectivity for butynediol and propargyl alcohol under normal acetylene pressure and without the introduction of organic solvents is a common concern for both industry and academia. Summary of the Invention

[0004] The object of the present invention is to provide a copper-based solid catalyst with controllable phase interface, a preparation method thereof, and an application thereof. To achieve the above object, the present invention provides the following technical solutions: A copper-based solid catalyst with controllable phase interface uses metal salts as copper, bismuth and manganese sources, and a bidentate complexing agent containing the element C as a directing agent. The metal salt and the complexing agent are mixed and pre-self-assembled in a solution to form a coordination complex, which is then dried and calcined to obtain the copper-based solid catalyst. A porous carbon shell with controllable hydrophilicity and thickness is in situ formed on the outer layer of the copper-based solid catalyst, and the copper center synergistic sites are confined by the carbon layer, thereby regulating the relative enrichment of formaldehyde molecules in the aqueous solution and gas-phase acetylene molecules at the surface interface of the solid catalyst.

[0005] Preferably, the complexing agent is one or any combination of melamine, ethylenediaminetetraacetic acid, and dicyandiamide.

[0006] Preferably, the copper source is one or any combination of copper nitrate, copper sulfate, and copper chloride.

[0007] Preferably, the manganese source is one or any combination of manganese nitrate, manganese sulfate, and manganese chloride.

[0008] Preferably, the bismuth source is bismuth nitrate.

[0009] The method for preparing a copper-based solid catalyst with controllable phase interface comprises the following steps: S1. According to the catalyst composition ratio, copper salt, manganese salt, bismuth salt and complexing agent are dissolved in water or ethanol to prepare a mixed solution with a molar ratio of metal ions to complexing agent of 1:1 to 1:3.5 to form a homogeneous complexing system; S2. Drying and cooling the homogeneous complex system to obtain a solid precursor; S3. calcining the solid precursor in a mixed atmosphere of nitrogen, carbon dioxide and water vapor.

[0010] Preferably, the mixed solution in step S1 is obtained by fully mixing at 30-60°C.

[0011] Preferably, the drying and cooling treatment in step S2 is to transfer the mixed solution to a rotary evaporator, evaporate to dryness under vacuum conditions at 60-90° C., and then cool to room temperature.

[0012] Preferably, the volume of the mixed atmosphere in step S3 is calculated as 100%, the volume ratio of nitrogen is 30% to 70%, the volume ratio of carbon dioxide is 20% to 60%, and the volume ratio of water vapor is 10% to 50%; the roasting temperature is 300 to 700°C, and the roasting time is 1 to 5 hours.

[0013] Application of the copper-based solid catalyst with controllable phase interface or the copper-based solid catalyst obtained by the preparation method in the synthesis of 1,4-butynediol by formaldehyde acetylation reaction.

[0014] The beneficial effects of the present invention compared to the prior art are: 1. The catalyst precursor of the present invention is a metal ion complex. When calcined under different atmospheres, temperatures, and times, a porous carbon shell of varying hydrophilicity and thickness can be formed in situ. Furthermore, the synergistic effect between the copper center and other components can be influenced by varying the addition ratios of the components. Therefore, the catalyst possesses controllable gas-liquid-solid three-phase interfacial activity. Specifically, the hydrophilicity of the carbon shell can influence the degree of contact between the catalyst and formaldehyde molecules in the aqueous solution; the thickness of the carbon shell can alter the diffusion behavior of formaldehyde and acetylene molecules; and the synergistic effect of the copper species on the catalyst surface and other components further improves the adsorption capacity of acetylene molecules on the catalyst surface. By constructing a microenvironment with adjustable relative enrichment of the reactants formaldehyde and acetylene molecules on the catalyst surface, the catalytic reaction process is influenced, thereby achieving the selective synthesis of propargyl alcohol and butynediol.

[0015] 2. The catalyst precursor of the present invention is a metal ion complex with uniformly dispersed metal ions. After calcination, the components interact appropriately, and the in-situ formed carbon layer coats the active centers, preventing the migration and aggregation of active species and facilitating the exposure of more active sites.

[0016] 3. The catalyst of the present invention can achieve the selective and controllable synthesis of the products butynediol and propynyl alcohol under normal acetylene pressure, which is safer and more economical than traditional industrial processes.

[0017] In summary, the active copper core, coated with a porous carbon shell with controllable gas-liquid-solid interface activity, not only overcomes the hydration of the silicon-based support of industrial catalysts in aqueous reaction systems and improves catalyst stability. More importantly, the carbon shell's liquid-solid interface activity (i.e., hydrophilicity and hydrophobicity) can be manipulated to influence the contact between formaldehyde molecules and the catalyst in aqueous solution. Furthermore, the thickness of the carbon shell can influence the mass transfer between formaldehyde and acetylene molecules. The synergistic effect of the copper species on the catalyst surface and other components further improves the adsorption capacity of acetylene molecules on the catalyst surface. Therefore, during the acetylation reaction, this catalyst can form an effectively controllable reaction microenvironment for acetylene in the gas phase, formaldehyde in the aqueous phase, and on the solid catalyst surface, thereby affecting the relative enrichment of the reactants, formaldehyde and acetylene, on the catalyst surface, enabling the selective and controllable synthesis of propargyl alcohol and butynediol. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a Raman graph of the copper-based solid catalyst with controllable phase interface prepared in Example 2 of the present invention.

[0019] Figure 2 This is the XRD pattern of the copper-based solid catalyst with controllable phase interface prepared in Example 2 of the present invention.

[0020] Figure 3 This is a contact angle test diagram of the copper-based solid catalyst with controllable phase interface prepared in Example 2 of the present invention.

[0021] Figure 4 This is a contact angle test diagram of the copper-based solid catalyst with controllable phase interface prepared in Example 4 of the present invention.

[0022] Figure 5 This is a contact angle test diagram of the copper-based solid catalyst with controllable phase interface prepared in Example 5 of the present invention.

[0023] Figure 6 This is a TEM image of the copper-based solid catalyst with controllable phase interface prepared in Example 2 of the present invention. DETAILED DESCRIPTION

[0024] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail with reference to the embodiments and the accompanying drawings. It should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention. The technical solutions of the present invention will be described in detail below with reference to the embodiments and the accompanying drawings, but the scope of protection is not limited thereto.

[0025] Unless otherwise specified, the production processes, experimental methods or detection methods involved in the embodiments of the present invention are all conventional methods in the prior art, and their names and / or abbreviations are conventional names in the field and are very clear and unambiguous in the relevant fields of use. Those skilled in the art can understand the conventional process steps based on the names and apply the corresponding equipment to implement them according to conventional conditions or the conditions recommended by the manufacturer.

[0026] The various instruments, equipment, raw materials or reagents used in the embodiments of the present invention are not particularly limited in their sources and are all conventional products that can be purchased through regular commercial channels or prepared according to conventional methods well known to those skilled in the art. Example

[0027] This embodiment proposes a copper-based solid catalyst with controllable phase interface and a preparation method thereof, the preparation method comprising the following steps: Step 1. Take metal salts: 24.16 g Cu(NO3)2·3H2O, 2.87 g Mn(NO3)2·6H2O, 4.85 g Bi(NO3)3·5H2O and complexing agent: 14.50 g melamine, dissolve them in 250 mL deionized water to prepare a mixed solution with a molar ratio of metal ions to complexing agent of 1:1; stir with ultrasonic assistance at 40°C for 20 min to form a homogeneous complex system.

[0028] Step 2: Transfer the mixed solution prepared in step 1 to a rotary evaporator, evaporate to dryness under vacuum at 80°C, and collect the solid precursor after cooling to room temperature for later use.

[0029] Step 3: calcine the solid precursor at 400 °C for 4 h in a mixed atmosphere of 40% N2, 40% CO2 and 20% H2O, and cool to room temperature to obtain a carbon layer-coated copper-based solid catalyst.

[0030] The outer layer of the obtained copper-based solid catalyst is a porous carbon shell layer with controllable hydrophilicity and thickness. The copper center synergistic sites are confined by the carbon layer, with extremely high dispersion and full exposure. Example

[0031] This embodiment proposes a copper-based solid catalyst with controllable phase interface and a preparation method thereof, the preparation method comprising the following steps: Step 1. Take metal salts: 17.05 g CuCl2·2H2O, 2.87 g Mn(NO3)2·6H2O, 4.85 g Bi(NO3)3·5H2O and complexing agent: 21.76 g melamine, dissolve them in 250 mL deionized water to prepare a mixed solution with a molar ratio of metal ions to complexing agent of 1:1.5; stir with ultrasonic assistance at 60°C for 20 min to form a homogeneous complex system.

[0032] Step 2: Transfer the mixed solution prepared in step 1 to a rotary evaporator, evaporate to dryness under vacuum at 80°C, and collect the solid precursor after cooling to room temperature for later use.

[0033] Step 3: calcine the solid precursor at 400 °C for 3 h in a mixed atmosphere of 50% N2, 40% CO2 and 10% H2O, and cool to room temperature to obtain a carbon layer-coated copper-based solid catalyst.

[0034] The outer layer of the obtained copper-based solid catalyst is a porous carbon shell layer with controllable hydrophilicity and thickness. The copper center synergistic sites are confined by the carbon layer, with extremely high dispersion and full exposure. Example

[0035] This embodiment proposes a copper-based solid catalyst with controllable phase interface and a preparation method thereof, the preparation method comprising the following steps: Step 1. Take metal salts: 17.05 g CuCl2·2H2O, 1.26 g MnCl2, 4.85 g Bi(NO3)3·5H2O and complexing agent: 50.41 g ethylenediaminetetraacetic acid, dissolve them in 250 mL ethanol to prepare a mixed solution with a molar ratio of metal ions to complexing agent of 1:1.5; stir with ultrasonic assistance at 60°C for 30 min to form a homogeneous complexing system.

[0036] Step 2: Transfer the mixed solution prepared in step 1 to a rotary evaporator, evaporate to dryness under vacuum at 60°C, and collect the solid precursor after cooling to room temperature for later use.

[0037] Step 3: calcine the solid precursor at 450°C for 4 h in a mixed atmosphere of 40% N2, 30% CO2 and 30% H2O, and cool to room temperature to obtain a carbon layer-coated copper-based solid catalyst.

[0038] The outer layer of the obtained copper-based solid catalyst is a porous carbon shell layer with controllable hydrophilicity and thickness. The copper center synergistic sites are confined by the carbon layer, with extremely high dispersion and full exposure. Example

[0039] This embodiment proposes a copper-based solid catalyst with controllable phase interface and a preparation method thereof, the preparation method comprising the following steps: Step 1. Take metal salts: 24.16 g Cu(NO3)2·3H2O, 1.26 g MnCl2, 4.85 g Bi(NO3)3·5H2O and complexing agent: 67.22 g ethylenediaminetetraacetic acid, dissolve them in 250 mL ethanol to prepare a mixed solution with a molar ratio of metal ions to complexing agent of 1:2; stir with ultrasonic assistance at 60°C for 30 min to form a homogeneous complex system.

[0040] Step 2: Transfer the mixed solution prepared in step 1 to a rotary evaporator, evaporate to dryness under vacuum at 60°C, and collect the solid precursor after cooling to room temperature for later use.

[0041] Step 3: calcine the solid precursor at 600 °C for 4 h in a mixed atmosphere of 50% N2, 20% CO2 and 30% H2O, and cool to room temperature to obtain a carbon layer-coated copper-based solid catalyst.

[0042] The outer layer of the obtained copper-based solid catalyst is a porous carbon shell layer with controllable hydrophilicity and thickness. The copper center synergistic sites are confined by the carbon layer, with extremely high dispersion and full exposure. Example

[0043] This embodiment proposes a copper-based solid catalyst with controllable phase interface and a preparation method thereof, the preparation method comprising the following steps: Step 1. Dissolve 24.97 g of CuSO4·5H2O, 1.69 g of MnSO4·H2O, 4.85 g of Bi(NO3)3·5H2O, and 24.17 g of dicyandiamide (a complexing agent) in 250 mL of deionized water to prepare a mixed solution with a molar ratio of metal ions to complexing agent of 1:2.5. Stir the mixture under ultrasonication at 50°C for 20 min to form a homogeneous complexing system.

[0044] Step 2: Transfer the mixed solution prepared in step 1 to a rotary evaporator, evaporate to dryness under vacuum at 80°C, and collect the solid precursor after cooling to room temperature for later use.

[0045] Step 3: calcine the solid precursor at 500 °C for 3 h in a mixed atmosphere of 45% N2, 40% CO2 and 15% H2O, and cool to room temperature to obtain a carbon layer-coated copper-based solid catalyst.

[0046] The outer layer of the obtained copper-based solid catalyst is a porous carbon shell layer with controllable hydrophilicity and thickness. The copper center synergistic sites are confined by the carbon layer, with extremely high dispersion and full exposure.

[0047] The catalytic performance of the copper-based solid catalyst with controllable phase interface prepared in Examples 1-5 and the industrial copper-bismuth catalyst was evaluated: 5.0 g of the copper-based solid solution catalyst prepared in the above Examples 1-5 and 50 mL of formaldehyde solution were placed in a slurry bed reactor. Under the conditions of reaction temperature of 90 ° C, reaction pressure of normal pressure, and acetylene flow rate of 60 mL / min, the catalytic performance and cycle stability of the copper-based catalyst with controllable phase interface in the acetylation reaction were investigated.

[0048]

[0049]

[0050] It can be seen from the evaluation results in Tables 1 and 2 that the copper-based solid catalyst with controllable phase interface of the present invention has higher acetylation activity, controllable butynediol and propyne yields and stability.

[0051] The structure, morphology and surface chemical properties of the prepared copper-based solid catalyst with controllable phase interface were characterized by X-ray diffraction (XRD), laser Raman spectroscopy (Raman spectrum), transmission electron microscopy (TEM) and contact angle measurement (see Figures 1 to 6 ).Depend on Figure 1 The Raman spectrum shows that the prepared copper-based catalyst has characteristic Raman peaks of copper oxide and carbon materials. The XRD spectrum shows that the characteristic diffraction peaks of copper species in the prepared catalyst are relatively diffuse, and the characteristic peaks of bismuth and manganese species are not seen, indicating that the copper species particles are small and well dispersed, and the bismuth and manganese species are highly complexed with it (see Figure 2 ). Figure 3-5 The contact angle test shown in the figure shows that the contact angle of different catalysts is adjusted from 42 degrees to 128 degrees. The TEM image shows that the prepared copper-based catalyst is granular and the surface of the copper species is covered by a porous carbon layer (see Figure 6 ).

[0052] Additionally, in order to provide a concise description of exemplary embodiments, all features of an actual embodiment may not be described (i.e., those features that are not relevant to the best mode presently contemplated for carrying out the invention or those that are not relevant to implementing the invention).

[0053] It will be appreciated that in the development of any actual embodiment, as in any engineering or design project, numerous implementation-specific decisions may be made. Such a development effort may be complex and time-consuming, but will, for those of ordinary skill having the benefit of this disclosure, be a routine undertaking of design, fabrication, and production without undue experimentation.

[0054] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

[0055] The embodiments of the present invention are provided for the purpose of illustration and description. Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations of the present invention. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A copper-based solid catalyst with controllable phase interface, characterized in that: The method uses metal salts as copper sources, bismuth sources and manganese sources, and a bidentate complexing agent containing the C element as a directing agent. The metal salts and the complexing agent are mixed and pre-self-assembled in a solution to form a coordination complex, which is then dried and calcined to obtain a copper-based solid catalyst; a porous carbon shell layer with controllable hydrophilicity and thickness is in situ formed on the outer layer of the copper-based solid catalyst, and the copper center synergistic site is confined by the carbon layer.

2. A copper-based solid catalyst with controllable phase interface according to claim 1, characterized in that, The complexing agent is one or any combination of melamine, ethylenediaminetetraacetic acid and dicyandiamide.

3. A copper-based solid catalyst with controllable phase interface according to claim 1, characterized in that: The copper source is one or any combination of copper nitrate, copper sulfate and copper chloride.

4. A copper-based solid catalyst with controllable phase interface according to claim 1, characterized in that: The manganese source is one or any combination of manganese nitrate, manganese sulfate and manganese chloride.

5. A copper-based solid catalyst with controllable phase interface according to claim 1, characterized in that, The bismuth source is bismuth nitrate.

6. The method for preparing a copper-based solid catalyst with controllable phase interface according to any one of claims 1 to 5, wherein: The following steps are involved: S1. According to the catalyst composition ratio, copper salt, manganese salt, bismuth salt and complexing agent are dissolved in water or ethanol to prepare a mixed solution with a molar ratio of metal ions to complexing agent of 1:1 to 1:3.5 to form a homogeneous complexing system; S2. Drying and cooling the homogeneous complex system to obtain a solid precursor; S3. calcining the solid precursor in a mixed atmosphere of nitrogen, carbon dioxide and water vapor.

7. The method for preparing a copper-based solid catalyst with controllable phase interface according to claim 6, wherein: The mixed solution in step S1 is obtained by fully mixing at 30-60°C.

8. The method for preparing a copper-based solid catalyst with controllable phase interface according to claim 6, wherein: The drying and cooling treatment in step S2 is to transfer the mixed solution to a rotary evaporator, evaporate it to dryness under vacuum conditions at 60-90° C., and then cool it to room temperature.

9. The method for preparing a copper-based solid catalyst with controllable phase interface according to claim 6, wherein: In step S3, the volume of the mixed atmosphere is calculated as 100%, the volume ratio of nitrogen is 30% to 70%, the volume ratio of carbon dioxide is 20% to 60%, and the volume ratio of water vapor is 10% to 50%; the roasting temperature is 300 to 700°C, and the roasting time is 1 to 5 hours.

10. Use of the copper-based solid catalyst with controllable phase interface according to any one of claims 1 to 5 or the copper-based solid catalyst obtained by the preparation method according to any one of claims 7 to 9 in the synthesis of 1,4-butynediol by formaldehyde ethynylation.

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