Electrostatically assembled multi-active-component high-strength millimeter sphere catalyst as well as preparation method and application thereof
The preparation of high-strength millimeter spherical catalysts by electrostatic assembly method solves the problems of low catalyst strength and difficulty in filling fixed bed reactors in the prior art, and realizes the direct filling and continuous reaction of preparing high-mechanical strength catalysts on any surface.
Patent Information
- Application Number
- CN202411257573.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-09
- Publication Date
- 2024-12-13
AI Technical Summary
It is difficult to prepare millimeter spherical catalysts with high mechanical strength, and it is difficult to directly fill in a fixed bed reactor for continuous reaction, which has problems such as low interaction between particles and poor buckling structure and strength.
Using electrostatic assembly method, positively charged and negatively charged solid nanoparticles are magnetically stirred in water to form a mixed liquid, and continuously drips on the hydrophobic silica powder to form droplet millimeter balls, and the preparation of high-strength catalyst is achieved by slow drying.
A high-strength millimeter spherical catalyst is prepared on any substrate surface, with a mechanical strength of 17 to 70N, and can be directly loaded into a fixed bed reactor for continuous flow tandem catalytic reaction, and keeping the activity unchanged.
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Figure CN119114167A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the field of catalytic material preparation, and in particular relates to a high-strength millimeter-sphere catalyst with multiple active components assembled by electrostatic assembly, a preparation method and application thereof. Background Art
[0002] Macroscopically sized superparticles with controllable composition and high mechanical strength are frontier materials for future industrial applications due to their unique properties that cannot be achieved by nanoparticles. In the past few decades, solution-based assembly strategies and droplet-based assembly strategies, including emulsion methods, microfluidics methods, spray drying methods, etc., have been developed to obtain superparticles. However, these methods are limited to the preparation of nano- to micron-sized particles. Recently, evaporative self-assembly methods have overcome these challenges by dropping millimeter-sized droplets with dispersed particles onto superhydrophobic solid surfaces and then evaporating the liquid inside the droplets to drive the internal particle self-assembly. However, current methods require highly hydrophobic surfaces, and the complex internal (annular) liquid flow cannot be controlled during the evaporation and assembly process, resulting in unexpected buckling structures and unsatisfactory mechanical strength, making it difficult to directly fill these materials into fixed-bed reactors for continuous reactions. Summary of the invention
[0003] The present invention aims to solve the problems in the prior art of preparing millimeter balls required for industry, such as low interaction between particles leading to buckled structures caused by particle movement, difficulty in achieving precise regulation of the internal structure of the millimeter balls, need for a specific hydrophobic surface, high preparation cost, and low strength that makes it difficult to produce continuous and industrial products. The present invention provides a method for preparing a high-strength millimeter ball catalyst with multiple active components assembled electrostatically, and the obtained catalyst can be directly loaded into a fixed bed reactor for a continuous flow series catalytic reaction.
[0004] To achieve the above object, the technical solution of the present invention is as follows:
[0005] The first aspect of the present invention is a method for preparing a high-strength millimeter-sphere catalyst with multiple active components assembled electrostatically, comprising the following steps:
[0006] Step 1: adding positively charged solid nanoparticles, negatively charged solid nanoparticles and other charged or uncharged solid nanoparticles into water, and preparing a mixed solution by magnetic stirring;
[0007] Step 2: continuously drip the above mixed solution onto the hydrophobic silicon oxide powder spread on a flat surface, and roll to form a droplet millimeter ball with a silicon oxide hydrophobic shell layer;
[0008] Step 3: Collect the liquid droplet millimeter balls to the substrate surface and slowly dry them to obtain the electrostatically assembled high-strength millimeter ball catalyst with multiple active components.
[0009] Furthermore, the positively charged solid nanoparticles in step 1 are any one of mesoporous silica or solid spherical silica modified by 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane or diethylenetriaminepropyltrimethoxysilane; the negatively charged solid nanoparticles are any one of mesoporous silica or solid spherical silica modified by 3-mercaptopropyltrimethoxysilane, 2-(4-chlorosulfonylphenyl)ethyltrimethoxysilane, 2-(4-chlorosulfonylphenyl)ethyltrichlorosilane, carboxyethylsilanetriol sodium salt or N-(trimethoxysilylpropyl)ethylenediaminetriacetic acid sodium salt, and polystyrene spheres modified by sulfonic acid; other charged or uncharged solid nanoparticles are any one of mesoporous silica or solid spherical silica or polystyrene spheres loaded with metals or immobilized enzymes, molecular sieves, mesoporous alumina, solid spherical alumina, ferroferric oxide, titanium dioxide, ferric oxide, calcium carbonate, activated carbon, zeolite and hollow silica.
[0010] Furthermore, in step 1, the dosage ratio of the positively charged solid nanoparticles, the negatively charged solid nanoparticles, other charged or uncharged solid nanoparticles and deionized water is 0.1-0.5 g: 0.1-0.5 g: 0.1-0.5 g: 1-5 mL.
[0011] Furthermore, the hydrophobic silica powder in step 2 is any one of Wacker H18 hydrophobic fumed silica, Evonik Degussa R974, R972, R202, R812, R106, R8200 hydrophobic fumed silica and homemade hydrophobic mesoporous silica, and the homemade hydrophobic mesoporous silica is obtained by hydrophilic mesoporous silica grafting modification with hydrophobic silane.
[0012] Furthermore, in step 2, the thickness of the hydrophobic silicon oxide powder is 1.0 to 3.0 mm.
[0013] Furthermore, in step 3, the substrate surface is any one of a glass surface, a ceramic surface, a cardboard surface, a plastic surface, a wooden surface and a metal surface.
[0014] Furthermore, in step 3, the temperature of the slow drying is 20 to 40° C., and the time is 6 to 24 hours.
[0015] The second aspect of the present invention is a high-strength millimeter ball catalyst with multiple active components assembled electrostatically prepared by the preparation method described in the first aspect. The millimeter ball particle size is 1.0-5.0 mm, the mechanical strength is 17-70N, and solid particles with different components can be encapsulated inside.
[0016] The third aspect of the present invention is the application of the electrostatically assembled high-strength millimeter-sphere catalyst with multiple active components described in the second aspect, which is used to directly load it into a fixed bed reactor for continuous flow series catalytic reaction.
[0017] Furthermore, the continuous flow series catalytic reaction includes an α-alkylated nitrile synthesis reaction and an asymmetric epoxidation reaction of alkyl allylic malononitrile.
[0018] Compared with the prior art, the present invention has the following beneficial effects:
[0019] 1. The electrostatically assembled high-strength millimeter ball catalyst with multiple active components prepared by the present invention realizes the preparation of millimeter ball catalysts on any substrate surface; the positively charged solid nanoparticles and the negatively charged solid nanoparticles are tightly combined through electrostatic interaction, which enhances the stability of the millimeter ball skeleton structure and obtains a millimeter ball catalyst with a mechanical strength of up to 17 to 70N; by regulating the interaction between particles, the problems of buckling structure and strength difference caused by the flow of particles inside the droplets are improved; other charged or uncharged solid particles are distributed in the network structure formed by the positively charged solid nanoparticles and the negatively charged solid nanoparticles, which can be confined in the millimeter ball and ensure that the multi-active component millimeter ball has a high strength and participates in the series catalytic process;
[0020] 2. The electrostatically assembled high-strength millimeter-sphere catalyst with multiple active components prepared by the present invention is a microsphere with a particle size of millimeters, which can be directly filled into a fixed bed reactor for continuous flow series catalysis without post-treatment;
[0021] 3. The electrostatically assembled high-strength millimeter ball catalyst with multiple active components prepared by the present invention has a simple preparation method, low equipment investment, and can be prepared on any surface, breaking through the limitation of using a super-hydrophobic surface to prepare the millimeter ball. The conditions are mild, and the preparation process does not affect the initial activity of the active sites on the solid nanoparticles during the immobilization process, and the active sites on the solid nanoparticles will not be significantly lost during the immobilization process.
[0022] 4. The electrostatically assembled multi-active component high-strength millimeter ball catalyst prepared by the present invention has a surface hydrophobic silicon oxide shell layer that can effectively encapsulate droplets dispersed with solid particles, and is conducive to the preparation of millimeter balls on various substrate surfaces;
[0023] 5. The high-strength millimeter-sphere catalyst with multiple active components assembled electrostatically prepared by the present invention can be directly loaded into a fixed bed reactor for continuous synthesis. Taking the one-pot synthesis of α-alkylated nitrile as an example, the continuous reaction is more than 200 hours, the reaction conversion rate remains basically unchanged, and the activity of the amino spheres and sulfonic acid spheres remains basically unchanged, and the palladium content on the silicon oxide loaded with metal palladium is basically not lost. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 A schematic diagram of a high-strength millimeter ball of multiple active components assembled electrostatically in Example 1 of the present invention;
[0025] Figure 2 This is a particle size diagram of high-strength millimeter balls of multiple active components assembled electrostatically in Example 1 of the present invention;
[0026] Figure 3 The scanning electron microscope image of the internal structure and overall morphology of the high-strength millimeter ball with multiple active components assembled electrostatically in Example 1 of the present invention;
[0027] Figure 4 This is a particle size diagram of high-strength millimeter balls of multiple active components assembled electrostatically in Example 2 of the present invention;
[0028] Figure 5 A cross-sectional view of a high-strength millimeter ball of multiple active components assembled electrostatically in Example 2 of the present invention;
[0029] Figure 6 The internal structure and particle size diagram of the high-strength millimeter ball of multiple active components assembled electrostatically in Example 3 of the present invention;
[0030] Figure 7 The internal structure and particle size diagram of the high-strength millimeter ball of multiple active components assembled electrostatically in Example 4 of the present invention;
[0031] Figure 8 This is a particle size diagram of high-strength millimeter balls of multiple active components assembled electrostatically in Example 5 of the present invention. DETAILED DESCRIPTION
[0032] In order to facilitate understanding of the present invention, the present invention will be described more fully below. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.
[0033] Example 1
[0034] A method for preparing a high-strength millimeter-sphere catalyst with multiple active components assembled by electrostatic assembly, comprising the following steps:
[0035] (1) 0.2 g of diethylenetriaminopropyltrimethoxysilane-modified mesoporous silica nanoparticles, 0.2 g of sulfonic acid-modified polystyrene spheres, and 0.2 g of mesoporous silica nanoparticles loaded with metal palladium nanoparticles were added to 3.4 mL of deionized water and stirred to obtain a mixed solution.
[0036] (2) The mixed solution was added to a syringe with a needle inner diameter of 1.0 mm. The mixed solution was continuously dropped onto R974 hydrophobic silica powder with a thickness of 3.0 mm spread on the surface of a glass culture dish at a flow rate of 0.5 mL / min through a syringe pump. The droplets rolled slowly under the action of a shaker to form droplet millimeter balls with a silica hydrophobic shell.
[0037] (3) Collect the droplet millimeter balls onto a glass culture dish, and then place it in a constant temperature shaker to slowly dry it during the rolling process. The drying temperature is controlled at 25°C. During the drying process, the positively charged solid nanoparticles and the negatively charged solid nanoparticles in the droplets are co-assembled through electrostatic interactions. The droplets gradually shrink and the mechanical strength gradually increases. After 12 hours, millimeter balls with a mechanical strength of 35N are obtained. Figure 1 Schematic diagram of the millimeter ball prepared by the present invention. Figure 2 This is the particle size diagram of the prepared millimeter spheres. From the figure, it can be seen that millimeter spheres with a size of about 2 mm were prepared. Figure 3 This is a scanning electron microscope image of the internal structure and overall morphology of the prepared millimeter ball. It can be seen from the image that the prepared millimeter ball is a spherical particle with a smooth surface, and the interior is formed by the accumulation of silicon oxide, polystyrene balls and palladium-loaded silicon oxide nanoparticles of about 100nm.
[0038] Example 2
[0039] A method for preparing a high-strength millimeter-sphere catalyst with multiple active components assembled by electrostatic assembly, comprising the following steps:
[0040] (1) 0.2 g of diethylenetriaminopropyltrimethoxysilane-modified mesoporous silica nanoparticles, 0.2 g of sulfonic acid-modified polystyrene spheres, and 0.2 g of molecular sieves were added to 3.4 mL of deionized water and stirred to obtain a mixed solution.
[0041] (2) The mixed solution was added to a syringe with a needle inner diameter of 2.0 mm. The mixed solution was continuously dropped onto H18 hydrophobic silica powder with a thickness of 3.0 mm spread on the surface of a flat-bottomed ceramic evaporating dish at a flow rate of 0.7 mL / min through a syringe pump. The droplets rolled slowly under the action of a shaker to form droplet millimeter balls with a silica hydrophobic shell.
[0042] (3) Collect the droplet millimeter balls onto a flat-bottomed ceramic evaporating dish, and then place it in a constant temperature shaker to slowly dry it during the rolling process. The drying temperature is controlled at 25°C. During the drying process, the positively charged solid nanoparticles and the negatively charged solid nanoparticles in the droplets are co-assembled through electrostatic interactions. The droplets gradually shrink and the mechanical strength gradually increases. After 12 hours, millimeter balls with a mechanical strength of 46N are obtained. Figure 4 Figure 2 is the particle size diagram of the prepared millimeter spheres. Figure 5 This is a cross-sectional view of the prepared millimeter ball. It can be seen from the figure that the millimeter ball is a spherical particle with a size of 2.0 mm, and its interior is formed by the accumulation of silicon oxide, polystyrene balls and molecular sieve nanoparticles of about 100 nm.
[0043] Example 3
[0044] A method for preparing a high-strength millimeter-sphere catalyst with multiple active components assembled by electrostatic assembly, comprising the following steps:
[0045] (1) 0.2 g of diethylenetriaminopropyltrimethoxysilane-modified mesoporous silica nanoparticles, 0.2 g of sulfonic acid-modified polystyrene spheres, and 0.1 g of aluminum oxide were added to 2.0 mL of deionized water and stirred to obtain a mixed solution.
[0046] (2) The mixed solution was added to a syringe with a needle inner diameter of 1.2 mm. The mixed solution was continuously dropped onto R972 hydrophobic silica powder with a thickness of 2.0 mm spread on the surface of a polytetrafluoroethylene evaporating dish at a flow rate of 0.5 mL / min through a syringe pump. The droplets rolled slowly under the action of a shaker to form droplet millimeter balls with a silica hydrophobic shell.
[0047] (3) Collect the droplet millimeter balls onto a polytetrafluoroethylene evaporating dish, and then place them in a constant temperature shaker to slowly dry them during rolling. The drying temperature is controlled at 30°C. During the drying process, the positively charged solid nanoparticles and the negatively charged solid nanoparticles in the droplets are co-assembled through electrostatic interactions. The droplets gradually shrink and the mechanical strength gradually increases. After 10 hours, millimeter balls with a mechanical strength of 47N are obtained. Figure 6 Figure 3 shows the particle size and internal structure of the prepared millimeter sphere.
[0048] Example 4
[0049] A method for preparing a high-strength millimeter-sphere catalyst with multiple active components assembled by electrostatic assembly, comprising the following steps:
[0050] (1) 0.2 g of diethylenetriaminopropyltrimethoxysilane-modified mesoporous silica nanoparticles, 0.2 g of sulfonic acid-modified polystyrene spheres, and 0.1 g of ferrosoferric oxide were added to 2.0 mL of deionized water and stirred to obtain a mixed solution.
[0051] (2) The mixed solution was added to a syringe with a needle inner diameter of 1.5 mm. The mixed solution was continuously dropped onto R202 hydrophobic silica powder with a thickness of 3.0 mm spread on a flat stainless steel disc at a flow rate of 0.6 mL / min through a syringe pump. The droplets rolled slowly under the action of a shaker to form droplet millimeter balls with a silica hydrophobic shell.
[0052] (3) Collect the droplet millimeter balls onto a stainless steel disc, and then place them in a constant temperature shaker to slowly dry them during rolling. The drying temperature is controlled at 40°C. During the drying process, the positively charged solid nanoparticles and the negatively charged solid nanoparticles in the droplets are co-assembled through electrostatic interactions. The droplets gradually shrink and the mechanical strength gradually increases. After 4 hours, millimeter balls with a mechanical strength of 45N are obtained. Figure 7Figure 3 shows the particle size and internal structure of the prepared millimeter sphere.
[0053] Example 5
[0054] A method for preparing a high-strength millimeter-sphere catalyst with multiple active components assembled by electrostatic assembly, comprising the following steps:
[0055] (1) 0.2 g of mesoporous silica nanoparticles modified with 3-aminopropyltriethoxysilane, 0.2 g of polystyrene spheres modified with sulfonic acid, and 0.1 g of enzyme-immobilized silica nanoparticles were added to 2.0 mL of deionized water and stirred to obtain a mixed solution.
[0056] (2) The mixed solution was added to a syringe with a needle inner diameter of 1.0 mm. The mixed solution was continuously dropped onto R812 hydrophobic silica powder with a thickness of 3.0 mm spread on the surface of coated paper at a flow rate of 0.5 mL / min through a syringe pump. The droplets rolled slowly under the action of a shaker to form droplet millimeter balls with a silica hydrophobic shell.
[0057] (3) Collect the droplet millimeter balls onto coated paper, and then put them into a constant temperature shaker to slowly dry them during rolling. The drying temperature is controlled at 25°C. During the drying process, the positively charged solid nanoparticles and the negatively charged solid nanoparticles in the droplets are co-assembled through electrostatic interactions. The droplets gradually shrink and the mechanical strength gradually increases. After 8 hours, millimeter balls with a mechanical strength of 17N are obtained. Figure 8 Figure 2 is the particle size diagram of the prepared millimeter spheres.
[0058] Example 6
[0059] 0.2 g of the millimeter ball catalyst prepared in Example 1 was directly loaded into a fixed bed reactor with an inner diameter of 1.34 cm. The reactor temperature was set to 70° C. A toluene solution of 0.05 mol / L benzaldehyde dimethyl acetal and 0.05 mol / L ethyl cyanoacetate was introduced at a flow rate of 0.6 mL / h through a constant flow pump for reaction. The reaction was continued for 200 h, the conversion rate was maintained at more than 99.9%, and the yield of the generated ethyl 2-cyano-3-phenylpropanoate was greater than 97%.
[0060] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0061] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.
Claims
1. A method for preparing a high-strength millimeter-sphere catalyst with multiple active components assembled by electrostatic assembly, characterized in that: The following steps are involved: Step 1: adding positively charged solid nanoparticles, negatively charged solid nanoparticles and other charged or uncharged solid nanoparticles into water, and preparing a mixed solution by magnetic stirring; Step 2: continuously drip the above mixed solution onto the hydrophobic silicon oxide powder spread on a flat surface, and roll to form a droplet millimeter ball with a silicon oxide hydrophobic shell layer; Step 3: Collect the liquid droplet millimeter balls to the substrate surface and slowly dry them to obtain the electrostatically assembled high-strength millimeter ball catalyst with multiple active components.
2. The method for preparing the high-strength millimeter-sphere catalyst with multiple active components assembled by electrostatic assembly according to claim 1, characterized in that: The positively charged solid nanoparticles in step 1 are any one of mesoporous silica or solid spherical silica modified by 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane or diethylenetriaminepropyltrimethoxysilane; the negatively charged solid nanoparticles are any one of mesoporous silica or solid spherical silica modified by 3-mercaptopropyltrimethoxysilane, 2-(4-chlorosulfonylphenyl)ethyltrimethoxysilane, 2-(4-chlorosulfonylphenyl)ethyltrichlorosilane, carboxyethylsilanetriol sodium salt or N-(trimethoxysilylpropyl)ethylenediaminetriacetic acid sodium salt, and polystyrene spheres modified by sulfonic acid; other charged or uncharged solid nanoparticles are any one of mesoporous silica or solid spherical silica or polystyrene spheres loaded with metals or immobilized enzymes, molecular sieves, mesoporous alumina, solid spherical alumina, ferroferric oxide, titanium dioxide, ferric oxide, calcium carbonate, activated carbon, zeolite and hollow silica.
3. The method for preparing the high-strength millimeter-sphere catalyst with multiple active components assembled by electrostatic assembly according to claim 1, characterized in that: In the step 1, the dosage ratio of the positively charged solid nanoparticles, the negatively charged solid nanoparticles, other charged or uncharged solid nanoparticles and deionized water is 0.1-0.5 g: 0.1-0.5 g: 0.1-0.5 g: 1-5 mL.
4. The method for preparing the high-strength millimeter-sphere catalyst with multiple active components assembled by electrostatic assembly according to claim 1, characterized in that: The hydrophobic silica powder in step 2 is any one of Wacker H18 hydrophobic fumed silica, Evonik Degussa R974, R972, R202, R812, R106, R8200 hydrophobic fumed silica and homemade hydrophobic mesoporous silica, wherein the homemade hydrophobic mesoporous silica is obtained by hydrophilic mesoporous silica grafting modification with hydrophobic silane.
5. The method for preparing the high-strength millimeter-sphere catalyst with multiple active components assembled by electrostatic assembly according to claim 1, characterized in that: The thickness of the hydrophobic silicon oxide powder in step 2 is 1.0 to 3.0 mm.
6. The method for preparing a high-strength millimeter-sphere catalyst with multiple active components assembled by electrostatic assembly according to claim 1, characterized in that: In step 3, the substrate surface is any one of a glass surface, a ceramic surface, a cardboard surface, a plastic surface, a wooden surface and a metal surface.
7. The method for preparing a high-strength millimeter-sphere catalyst with multiple active components assembled by electrostatic assembly according to claim 1, characterized in that: The temperature of the slow drying in step 3 is 20 to 40° C. and the time is 6 to 24 hours.
8. The high-strength millimeter-sphere catalyst with multiple active components assembled by the preparation method according to any one of claims 1 to 7, characterized in that: The particle size of the millimeter sphere is 1.0 to 5.0 mm, the mechanical strength is 17 to 70N, and solid particles with different components can be encapsulated inside.
9. The use of the electrostatically assembled multi-active component high-strength millimeter ball catalyst according to claim 8, characterized in that: Used to directly load into fixed bed reactor for continuous flow series catalytic reaction.
10. The use of the electrostatically assembled multi-active component high-strength millimeter ball catalyst according to claim 9, characterized in that: The continuous flow series catalytic reaction comprises an α-alkylated nitrile synthesis reaction and an asymmetric epoxidation reaction of an alkyl allylic malononitrile.