A high-efficiency catalyst carrier material and a preparation method thereof

Abstract

This invention belongs to the field of catalyst support preparation technology, specifically relating to a high-efficiency catalyst support material and its preparation method. This invention adds a certain amount of polyethylene polyamine small molecule compound as a template agent to a hydroxypropyl-β-cyclodextrin template system. Using hydroxypropyl-β-cyclodextrin and the polyethylene polyamine small molecule compound as template agents, aluminum salt and aluminate are guided to form a precursor with a porous structure, which is finally obtained by calcination to obtain an alumina support. Adding a portion of hydroxypropyl-β-cyclodextrin to the aluminate solution in advance acts as a buffer, reducing the influence of the polyethylene polyamine small molecule compound on the solution system, promoting a more complete and uniform reaction between the aluminum salt and aluminate, reducing the direct interaction of interparticle hydrogen bonds, thereby effectively preventing hard agglomeration caused by capillary forces and increasing the specific surface area and pore size of alumina.

Description

Technical Field

[0001] This invention belongs to the field of catalyst support preparation technology, specifically relating to a high-efficiency catalyst support material and its preparation method. Background Technology

[0002] With the development of catalysis science and nanomaterials, more than 80% of chemical production processes now rely on catalysis. A catalyst is defined as "a chemical substance that can change the rate of a chemical reaction without altering its thermodynamic equilibrium position, and is not significantly consumed in the reaction." These substances can be metals, metal oxides, organic complexes, or enzymes. Therefore, to improve catalytic performance, modification of the catalyst itself is necessary, and nanomaterials, as active components or carriers, have become a hot research topic.

[0003] Porous materials play a crucial role in the adsorption, separation, and especially catalytic reactions of substances due to their advantages such as high specific surface area, ordered channels, continuously tunable pore size, and controllable microstructure. Porous alumina, with its high mechanical strength, large specific surface area, excellent thermal and chemical stability, unique channels, and ease of loading different metal species, has gradually attracted attention and is widely used in the field of catalysis, becoming the most commonly used catalyst support. Alumina loaded with noble metals such as gold, palladium, and platinum exhibits excellent catalytic activity in oxidation. However, numerous experiments have shown that the high dispersion and particle size of nano-metal particles on the support are prerequisites for high catalytic activity. To prepare highly active supported nano-metal catalysts, different types, sizes, and morphologies of catalyst supports are typically used to stabilize and disperse metal particles. Therefore, the current challenge remains the controllable preparation of alumina morphology and surface structure.

[0004] CN119972035A provides an alumina support, its preparation method, and its application. The preparation method includes: calcining a precursor comprising an aluminum-containing component, a solvent, a binder, a morphology control agent, and water to obtain the alumina support; the aluminum-containing component comprises a first aluminum-containing compound and a second aluminum-containing compound, wherein the first aluminum-containing compound has a particle size of 10-25 μm, and the second aluminum-containing compound has a particle size of 30-60 μm. By using alumina with two different particle sizes in combination and adding a suitable morphology control agent, the problem of alumina supports prepared by various alumina molding processes breaking down upon contact with water is solved.

[0005] CN120515398A discloses a method for preparing and applying a microporous alumina support. The preparation method includes the following steps: Step 1: Crush waste ethylene oxide catalyst; Step 2: Acid leaching of silver from the crushed waste ethylene oxide catalyst, filtering to obtain a silver-containing leachate, and washing the remaining solid with water to obtain an alumina filter cake; Step 3: Support preparation: Mixing the alumina filter cake, hard template pore-expanding agent, binder, molding extrusion aid, and sintering aid; adding an aqueous solution containing a crosslinking agent, kneading; extruding and pelletizing; drying and calcining to obtain a microporous alumina support. By utilizing three measures—the accumulation of crushed particles into secondary pores, the in-situ decomposition of the hard template agent into long strip-shaped ultra-large micropores, and the crosslinking and coagulation of organic polymers into interconnecting pores—the permeability of the pores is improved, the pore size is increased, and the diffusion performance of the support is enhanced, allowing it to accommodate more iron scale.

[0006] CN111939885A also discloses an alumina carrier with adjustable pore size and its preparation method. In this alumina carrier, the pore size gradually increases from the center to the outer surface along the diameter of the particles. The pore diameter at the particle center is 1-8 nm smaller than the average pore diameter at 50% of the particle size, the average pore diameter at 50% of the particle size is about 1-5 nm smaller than the average pore diameter at 80% of the particle size, and the average pore diameter at 80% of the particle size is 1-5 nm smaller than the average pore diameter at the outer surface of the particles. The water absorption rate is 65%-75%, and the specific surface area is 120-220 m². 2 The alumina support has a pore volume of 0.6-0.8 mL / g and a pore diameter distribution of 10 nm-20 nm. The pore diameter exhibits a trumpet-shaped distribution that gradually increases radially from the particle center to the outer surface. Compared to supports with concentrated pore distribution, this alleviates the problem of low active component loading caused by pore blockage on the outer surface and allows for relatively convenient adjustment of the support's pore size. While this process improves the pore size and specific surface area of ​​the alumina support to some extent, its preparation process is complex, inefficient, and difficult to promote for industrial use. Summary of the Invention

[0007] To address the technical problems of complex and inefficient existing catalyst support preparation processes, this invention provides a high-efficiency catalyst support material and its preparation method. This method is simple, efficient, and can be used for large-scale preparation. Furthermore, the prepared alumina support has a large specific surface area and pore size, meeting the current requirements for high efficiency, economy, and environmental protection.

[0008] Based on the above objectives, this invention provides a method for preparing a high-efficiency catalyst support material, comprising the following steps:

[0009] A method for preparing a high-efficiency catalyst support material includes the following steps:

[0010] (1) Add aluminum salt and first hydroxypropyl-β-cyclodextrin to deionized water, and disperse evenly by ultrasonication to obtain a mixed solution of aluminum salt;

[0011] (2) Add aluminate, second hydroxypropyl-β-cyclodextrin, and polyethylenepolyamine small molecule compound to deionized water to obtain a mixed solution of aluminate; the number of nitrogen atoms in the polyethylenepolyamine small molecule compound is greater than 2; the mass ratio of the polyethylenepolyamine small molecule compound to the sum of the masses of the first hydroxypropyl-β-cyclodextrin and the second hydroxypropyl-β-cyclodextrin is (0.05-0.2):1;

[0012] (3) Under stirring conditions, the aluminate mixed solution is added dropwise to the aluminum salt mixed solution to obtain the precursor solution, and the precursor solution is adjusted to be alkaline;

[0013] (4) After the addition is complete, continue stirring for a period of time, and then heat up to react; after post-processing and calcining the product, a high-efficiency catalyst support material is obtained.

[0014] This invention selects hydroxypropyl-β-cyclodextrin as a template agent for alumina. Hydroxypropyl-β-cyclodextrin has a higher number of hydroxyl groups than α-cyclodextrin, and it contains hydroxypropyl groups, which not only endows the cyclodextrin with a branched structure but also improves its solubility, giving it a cyclic structure with an internal lipophilic and an external hydrophilic nature. Compared to the commonly used linear polyethylene glycol and polyvinyl alcohol surfactants in alumina preparation, it is more conducive to forming a loose porous structure, improving the porosity and pore size of the alumina support. In previous work (CN118788318A), the inventors used hydroxypropyl-β-cyclodextrin as a template agent and surfactant to prepare porous alumina supports. However, the alumina supports prepared by this process had a small specific surface area and limited improvement in pore size. Although the inventors later improved the specific surface area of ​​the alumina support by adding organic polymers such as polyvinyl alcohol as template agents, polyvinyl alcohol has poor solubility. It usually requires heating to completely dissolve in water, making the solution preparation process cumbersome and time-consuming. Furthermore, the solution is prone to gel formation after cooling, which affects the uniformity of subsequent use.

[0015] Therefore, this invention adds a certain amount of polyethylene polyamine small molecule compound as a template agent to the hydroxypropyl-β-cyclodextrin template system. Utilizing the unique properties of both hydroxypropyl-β-cyclodextrin and the polyethylene polyamine small molecule compound as template agents, a precursor with a hierarchical porous structure is guided to form from aluminum salts and aluminates through a synergistic template effect. Finally, after calcination, a high specific surface area and large pore size alumina support is obtained. The hydroxypropyl-β-cyclodextrin molecule itself is a truncated pyramidal hollow macrocyclic molecule, and its hydroxypropyl substituent enhances its water solubility and compatibility with inorganic substances. During the formation of the aluminum precursor, the hydroxypropyl-β-cyclodextrin molecule is encapsulated or adsorbed between the growing particles. Its large volume physically occupies space, preventing the compact packing of particles. After the hydroxypropyl-β-cyclodextrin is removed, large-sized cavities are left in the positions it previously occupied, thus forming large pores. Although hydroxypropyl-β-cyclodextrin is not a traditional surfactant, its amphiphilic structure (hydrophilic outer wall and relatively hydrophobic inner cavity) allows it to interact with inorganic species to some extent. It can act as a soft template to guide the deposition of aluminum precursors around its exterior, forming a channel that "replicates" its external structure.

[0016] In this system, polyethylenepolyamine small molecule compounds play a role in structural regulation and stabilization. They can form hydrogen bonds with numerous hydroxyl groups on the hydroxypropyl-β-cyclodextrin molecule, helping to maintain small crystallite sizes. Simultaneously, as organic bases with multidentate ligands, polyethylenepolyamine small molecule compounds facilitate the slow and uniform co-precipitation of aluminum salts and aluminates, promoting the formation of porous alumina structures. Furthermore, the nitrogen atoms in the polyethylenepolyamine small molecule compounds possess lone pairs of electrons, enabling strong complexation with aluminum ions to form stable, soluble complexes, promoting the uniform and orderly formation of precursors and contributing to a more stable framework and more developed pores. Additionally, as small linear molecules, polyethylenepolyamine small molecule compounds can fill the smaller gaps in the precursor, contributing smaller mesopores and forming a pore gradation with the macropores generated by hydroxypropyl-β-cyclodextrin, further optimizing the pore structure. However, the amount of polyethylenepolyamine small molecule compounds should not be excessive; otherwise, excessive cross-linking with hydroxypropyl-β-cyclodextrin through hydrogen bonding can lead to the formation of stacked structures, which is detrimental to increasing the specific surface area of ​​the alumina support.

[0017] Specifically, this invention adds hydroxypropyl-β-cyclodextrin to both the aluminum salt solution and the aluminate solution. When the aluminum salt solution and the aluminate solution are mixed, the reaction is very rapid, especially with the introduction of polyethylene polyamine small molecule compounds, which easily leads to localized pH inhomogeneities, resulting in heterogeneous product composition and structure. To address the problem of reaction inhomogeneity caused by polyethylene polyamine small molecule compounds, this invention adds a portion of hydroxypropyl-β-cyclodextrin to the aluminate solution. The hydroxypropyl-β-cyclodextrin added to the aluminate solution beforehand acts as a buffer, reducing the impact of polyethylene polyamine small molecule compounds on the solution system and improving mixing uniformity (this effect differs from the stepwise addition of hydroxypropyl-β-cyclodextrin described in the inventors' work CN118788318A). Furthermore, the thickening and surfactant properties of hydroxypropyl-β-cyclodextrin help improve the mixing effect of the solution, making the precipitation reaction more synchronous throughout the system, promoting a more complete and uniform reaction between the aluminum salt and the aluminate, and generating a precursor with a more uniform chemical composition. During the drying process of the precipitate, hydroxypropyl-β-cyclodextrin forms steric hindrance between particles, reducing the direct effect of hydrogen bonds between particles, thereby effectively preventing hard agglomeration caused by capillary forces and increasing the specific surface area and pore size of alumina.

[0018] In one embodiment, the aluminum salt in step (1) is one or more of aluminum nitrate, aluminum chloride, aluminum bromide, and aluminum sulfate; the concentration of aluminum salt in the aluminum salt mixed solution is 8-15 g / L. Specifically, the aluminum salt concentration can be 8 g / L, 9 g / L, 10 g / L, 11 g / L, 12 g / L, 13 g / L, 14 g / L, or 15 g / L.

[0019] In one embodiment, the mass ratio of the first hydroxypropyl-β-cyclodextrin to the aluminum salt is (0.1-0.2):1. Specifically, the mass ratio of the first hydroxypropyl-β-cyclodextrin to the aluminum salt can be 0.1:1, 0.12:1, 0.14:1, 0.16:1, 0.18:1, or 0.2:1.

[0020] In one embodiment, the aluminate in step (2) is one or more of sodium aluminate or potassium aluminate.

[0021] In one embodiment, the mass ratio of aluminate to aluminum salt is (0.6-0.8):1; the concentration of aluminate in the aluminate mixed solution is 5-10 g / L. This appropriate concentration ensures a sufficiently high nucleation rate to obtain a high specific surface area, while preventing the reaction from becoming too vigorous and out of control, and also takes into account the convenience of filtration and washing.

[0022] In one embodiment, the polyethylenepolyamine small molecule compound is one or more of diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexaethyleneheptamine, heptaethyleneoctamine, octaethylenenonamine, nonaethylenedeamine, and decaethyleneundecanamine. The nitrogen atoms in the polyethylenepolyamine small molecule compound possess lone pairs of electrons, which can undergo strong complexation with aluminum ions, promoting the formation of a uniform precursor structure. Specifically, polyethylenepolyamine small molecule compounds with different numbers of nitrogen atoms can be used in combination. Polyethylenepolyamine small molecule compounds with different chain lengths and nitrogen atom numbers can promote the formation of interparticle pores and increase the specific surface area of ​​alumina. For example, diethylenetriamine and triethylenetetramine, or diethylenetriamine and tetraethylenepentamine, can be used in combination. Further, diethylenetriamine and tetraethylenepentamine can be selected as the two polyethylenepolyamine small molecule compounds, and the amounts of both are not particularly limited. Specifically, the molar ratio of diethylenetriamine to tetraethylenepentamine can be (0.2-4):1; further, it can be (1.5-3):1.

[0023] In one embodiment, the mass ratio of the second hydroxypropyl-β-cyclodextrin to the aluminum salt is (0.03-0.1):1. An appropriate amount of the second hydroxypropyl-β-cyclodextrin can better reduce the influence of polyethylenepolyamine small molecule compounds on the solution system, improve mixing uniformity, and promote a more complete and uniform reaction between the aluminum salt and aluminate, generating a precursor with a more uniform chemical composition.

[0024] In one embodiment, the pH of the precursor solution is adjusted to 8-10 in step (3). The pH is adjusted by adding acidic substances such as hydrochloric acid, nitric acid, or acetic acid, or by using alkaline substances such as sodium hydroxide or ammonia.

[0025] In one embodiment, during the dropwise addition process, the aluminum salt mixture solution is heated to a temperature of 45-65°C; the dropwise addition rate is 8-14 mL / min.

[0026] In one embodiment, the stirring time is 0.5-1h; the reaction temperature is raised to 70-90℃ and the reaction time is raised to 1.5-3h.

[0027] In one embodiment, the post-treatment process is filtration, washing, and drying.

[0028] In one embodiment, the calcination temperature is 550-610℃ and the calcination time is 4-6h.

[0029] Beneficial effects:

[0030] Polyethylene polyamine small molecule compounds play a role in structural regulation and stabilization in the aluminum salt-aluminate system. They can form hydrogen bonds with numerous hydroxyl groups on the hydroxypropyl-β-cyclodextrin molecule, which helps maintain a small crystallite size. Simultaneously, this invention adds a portion of hydroxypropyl-β-cyclodextrin to the aluminate. The hydroxypropyl-β-cyclodextrin added to the aluminate solution beforehand acts as a buffer, reducing the impact of the polyethylene polyamine small molecule compounds on the solution system, improving mixing uniformity, and promoting a more complete and uniform reaction between the aluminum salt and aluminate, generating a precursor with a more uniform chemical composition. During the drying process of the precipitate, hydroxypropyl-β-cyclodextrin forms steric hindrance between particles, reducing the direct interaction of hydrogen bonds between particles, thereby effectively preventing hard agglomeration caused by capillary forces and increasing the specific surface area and pore size of alumina. Detailed Implementation

[0031] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0032] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0033] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0034] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials, reagents, methods, and instruments used are all conventional materials, reagents, methods, and instruments in the art, and can be obtained commercially by those skilled in the art.

[0035] Unless otherwise specified, the preparation processes and raw materials of the following examples and comparative examples are the same.

[0036] Performance testing: The specific surface area, pore size, and pore volume of the high-efficiency catalyst support materials prepared in the following examples and comparative examples were tested using the BET method.

[0037] Example 1

[0038] A method for preparing a high-efficiency catalyst support material includes the following steps:

[0039] (1) Add aluminum salt aluminum nitrate and first hydroxypropyl-β-cyclodextrin to deionized water, and disperse evenly by ultrasonication to obtain an aluminum salt mixed solution; the concentration of aluminum salt in the aluminum salt mixed solution is 8 g / L; the mass ratio of first hydroxypropyl-β-cyclodextrin to aluminum salt is 0.1:1;

[0040] (2) Sodium aluminate, second hydroxypropyl-β-cyclodextrin, and polyethylenepolyamine small molecule compound were added to deionized water to obtain a mixed solution of aluminate; the polyethylenepolyamine small molecule compound was diethylenetriamine; the mass ratio of the polyethylenepolyamine small molecule compound to the sum of the masses of the first hydroxypropyl-β-cyclodextrin and the second hydroxypropyl-β-cyclodextrin was 0.05:1; the mass ratio of aluminate to aluminum salt was 0.6:1; the concentration of aluminate in the mixed solution of aluminate was 6 g / L; the mass ratio of second hydroxypropyl-β-cyclodextrin to aluminum salt was 0.1:1;

[0041] (3) Under stirring conditions, the aluminate mixture solution was added dropwise to the aluminum salt mixture solution to obtain the precursor solution, and the pH of the precursor solution was adjusted to 8; during the dropwise addition, the aluminum salt mixture solution was heated to 45℃; the dropwise acceleration rate was 8 mL / min.

[0042] (4) After the addition is complete, continue stirring for 0.5 h, then raise the temperature to 70℃ and react for 3 h; filter, wash, dry, and calcine the product to obtain the high-efficiency catalyst support material; the calcination temperature is 550℃ and the calcination time is 6 h. The specific surface area of ​​this support material is tested to be 320 m². 2 / g, pore size 17.3nm, pore volume 1.35cm³ 3 / g.

[0043] Example 2

[0044] A method for preparing a high-efficiency catalyst support material includes the following steps:

[0045] (1) Add aluminum salt aluminum nitrate and first hydroxypropyl-β-cyclodextrin to deionized water, and disperse evenly by ultrasonication to obtain an aluminum salt mixed solution; the concentration of aluminum salt in the aluminum salt mixed solution is 13 g / L; the mass ratio of first hydroxypropyl-β-cyclodextrin to aluminum salt is 0.2:1;

[0046] (2) Sodium aluminate, second hydroxypropyl-β-cyclodextrin, and polyethylenepolyamine small molecule compound were added to deionized water to obtain a mixed solution of aluminate; the polyethylenepolyamine small molecule compound was triethylenetetramine; the mass ratio of the polyethylenepolyamine small molecule compound to the sum of the masses of the first hydroxypropyl-β-cyclodextrin and the second hydroxypropyl-β-cyclodextrin was 0.2:1; the mass ratio of aluminate to aluminum salt was 0.8:1; the concentration of aluminate in the mixed solution of aluminate was 8 g / L; the mass ratio of second hydroxypropyl-β-cyclodextrin to aluminum salt was 0.03:1;

[0047] (3) Under stirring conditions, the aluminate mixed solution was added dropwise to the aluminum salt mixed solution to obtain the precursor solution, and the pH of the precursor solution was adjusted to 10; during the dropwise addition, the aluminum salt mixed solution was heated to 65℃; the dropwise acceleration rate was 8mL / min.

[0048] (4) After the addition is complete, continue stirring for 1 hour, then raise the temperature to 90℃ and react for 1.5 hours; filter, wash, dry, and calcine the product to obtain the high-efficiency catalyst support material; the calcination temperature is 610℃ and the calcination time is 4 hours. The specific surface area of ​​this support material is measured to be 323 m². 2 / g, pore size 17.5nm, pore volume 1.34cm³ 3 / g.

[0049] Example 3

[0050] A method for preparing a high-efficiency catalyst support material includes the following steps:

[0051] (1) Add aluminum salt aluminum nitrate and first hydroxypropyl-β-cyclodextrin to deionized water and disperse evenly by ultrasonication to obtain an aluminum salt mixed solution; the concentration of aluminum salt in the aluminum salt mixed solution is 11 g / L; the mass ratio of first hydroxypropyl-β-cyclodextrin to aluminum salt is 0.15:1;

[0052] (2) Sodium aluminate, second hydroxypropyl-β-cyclodextrin, and polyethylenepolyamine small molecule compound were added to deionized water to obtain a mixed solution of aluminate; the polyethylenepolyamine small molecule compound was diethylenetriamine; the mass ratio of the polyethylenepolyamine small molecule compound to the sum of the masses of the first hydroxypropyl-β-cyclodextrin and the second hydroxypropyl-β-cyclodextrin was 0.13:1; the mass ratio of aluminate to aluminum salt was 0.7:1; the concentration of aluminate in the mixed solution of aluminate was 7 g / L; the mass ratio of second hydroxypropyl-β-cyclodextrin to aluminum salt was 0.06:1;

[0053] (3) Under stirring conditions, the aluminate mixed solution was added dropwise to the aluminum salt mixed solution to obtain the precursor solution, and the pH of the precursor solution was adjusted to 9; during the dropwise addition, the aluminum salt mixed solution was heated to 50℃; the dropwise acceleration rate was 11mL / min.

[0054] (4) After the addition is complete, continue stirring for 0.7 h, then raise the temperature to 80℃ and react for 2 h; filter, wash, dry, and calcine the product to obtain the high-efficiency catalyst support material; the calcination temperature is 580℃ and the calcination time is 5 h. The specific surface area of ​​this support material is tested to be 327 m². 2 / g, pore size 18.1nm, pore volume 1.39cm³ 3 / g.

[0055] Example 4

[0056] A method for preparing a high-efficiency catalyst support material includes the following steps:

[0057] (1) Add aluminum salt aluminum nitrate and first hydroxypropyl-β-cyclodextrin to deionized water, and disperse evenly by ultrasonication to obtain an aluminum salt mixed solution; the concentration of aluminum salt in the aluminum salt mixed solution is 8 g / L; the mass ratio of first hydroxypropyl-β-cyclodextrin to aluminum salt is 0.2:1;

[0058] (2) Sodium aluminate, second hydroxypropyl-β-cyclodextrin, and polyethylenepolyamine small molecule compound were added to deionized water to obtain a mixed solution of aluminate; the polyethylenepolyamine small molecule compound was a mixture of diethylenetriamine and triethylenetetramine in a molar ratio of 2:1; the mass ratio of the polyethylenepolyamine small molecule compound to the sum of the masses of first hydroxypropyl-β-cyclodextrin and second hydroxypropyl-β-cyclodextrin was 0.18:1; the mass ratio of aluminate to aluminum salt was 0.62:1; the concentration of aluminate in the mixed solution of aluminate was 7.5 g / L; the mass ratio of second hydroxypropyl-β-cyclodextrin to aluminum salt was 0.04:1;

[0059] (3) Under stirring conditions, the aluminate mixed solution was added dropwise to the aluminum salt mixed solution to obtain the precursor solution, and the pH of the precursor solution was adjusted to 8; during the dropwise addition, the aluminum salt mixed solution was heated to 46℃; the dropwise acceleration rate was 13mL / min.

[0060] (4) After the addition is complete, continue stirring for 0.5 h, then raise the temperature to 70℃ and react for 1.6 h; filter, wash, dry, and calcine the product to obtain the high-efficiency catalyst support material; the calcination temperature is 560℃ and the calcination time is 4.2 h. The specific surface area of ​​this support material is tested to be 337 m². 2 / g, pore size 19.2nm, pore volume 1.40cm³ 3 / g.

[0061] Example 5

[0062] A method for preparing a high-efficiency catalyst support material includes the following steps:

[0063] (1) Add aluminum salt aluminum nitrate and first hydroxypropyl-β-cyclodextrin to deionized water and disperse evenly by ultrasonication to obtain an aluminum salt mixed solution; the concentration of aluminum salt in the aluminum salt mixed solution is 11 g / L; the mass ratio of first hydroxypropyl-β-cyclodextrin to aluminum salt is 0.15:1;

[0064] (2) Sodium aluminate, second hydroxypropyl-β-cyclodextrin, and polyethylenepolyamine small molecule compound were added to deionized water to obtain a mixed solution of aluminate; the polyethylenepolyamine small molecule compound was tetraethylenepentamine; the mass ratio of the polyethylenepolyamine small molecule compound to the sum of the masses of the first hydroxypropyl-β-cyclodextrin and the second hydroxypropyl-β-cyclodextrin was 0.13:1; the mass ratio of aluminate to aluminum salt was 0.7:1; the concentration of aluminate in the mixed solution of aluminate was 7 g / L; the mass ratio of second hydroxypropyl-β-cyclodextrin to aluminum salt was 0.06:1;

[0065] (3) Under stirring conditions, the aluminate mixed solution was added dropwise to the aluminum salt mixed solution to obtain the precursor solution, and the pH of the precursor solution was adjusted to 9; during the dropwise addition, the aluminum salt mixed solution was heated to 50℃; the dropwise acceleration rate was 11mL / min.

[0066] (4) After the addition is complete, continue stirring for 0.7 h, then raise the temperature to 80℃ and react for 2 h; filter, wash, dry, and calcine the product to obtain the high-efficiency catalyst support material; the calcination temperature is 580℃ and the calcination time is 5 h. The specific surface area of ​​this support material is tested to be 331 m². 2 / g, pore size 18.3nm, pore volume 1.37cm³ 3 / g.

[0067] Example 6

[0068] A method for preparing a high-efficiency catalyst support material includes the following steps:

[0069] (1) Add aluminum salt aluminum nitrate and first hydroxypropyl-β-cyclodextrin to deionized water and disperse evenly by ultrasonication to obtain an aluminum salt mixed solution; the concentration of aluminum salt in the aluminum salt mixed solution is 9 g / L; the mass ratio of first hydroxypropyl-β-cyclodextrin to aluminum salt is 0.13:1;

[0070] (2) Sodium aluminate, second hydroxypropyl-β-cyclodextrin, and polyethylenepolyamine small molecule compound were added to deionized water to obtain a mixed solution of aluminate; the polyethylenepolyamine small molecule compound was a mixture of triethylenetetramine and tetraethylenepentamine in a molar ratio of 1.8:1; the mass ratio of the polyethylenepolyamine small molecule compound to the sum of the masses of first hydroxypropyl-β-cyclodextrin and second hydroxypropyl-β-cyclodextrin was 0.1:1; the mass ratio of aluminate to aluminum salt was 0.65:1; the concentration of aluminate in the mixed solution of aluminate was 6.5 g / L; the mass ratio of second hydroxypropyl-β-cyclodextrin to aluminum salt was 0.06:1;

[0071] (3) Under stirring conditions, the aluminate mixture solution was added dropwise to the aluminum salt mixture solution to obtain the precursor solution, and the pH of the precursor solution was adjusted to 9; during the dropwise addition, the aluminum salt mixture solution was heated to 50℃; the dropwise acceleration rate was 10mL / min.

[0072] (4) After the addition is complete, continue stirring for 0.7 h, then raise the temperature to 75℃ and react for 2.5 h; filter, wash, dry, and calcine the product to obtain a high-efficiency catalyst support material; the calcination temperature is 570℃ and the calcination time is 5.5 h. The specific surface area of ​​this support material is tested to be 325 m². 2 / g, pore size 17.4nm, pore volume 1.36cm³ 3 / g.

[0073] Example 7

[0074] A method for preparing a high-efficiency catalyst support material includes the following steps:

[0075] (1) Add aluminum salt aluminum nitrate and first hydroxypropyl-β-cyclodextrin to deionized water and disperse evenly by ultrasonication to obtain an aluminum salt mixed solution; the concentration of aluminum salt in the aluminum salt mixed solution is 11 g / L; the mass ratio of first hydroxypropyl-β-cyclodextrin to aluminum salt is 0.15:1;

[0076] (2) Sodium aluminate, second hydroxypropyl-β-cyclodextrin, and polyethylenepolyamine small molecule compound were added to deionized water to obtain a mixed solution of aluminate; the polyethylenepolyamine small molecule compound was a mixture of diethylenetriamine and tetraethylenepentamine in a molar ratio of 1:2.5; the mass ratio of the polyethylenepolyamine small molecule compound to the sum of the masses of first hydroxypropyl-β-cyclodextrin and second hydroxypropyl-β-cyclodextrin was 0.13:1; the mass ratio of aluminate to aluminum salt was 0.7:1; the concentration of aluminate in the mixed solution of aluminate was 7 g / L; the mass ratio of second hydroxypropyl-β-cyclodextrin to aluminum salt was 0.06:1;

[0077] (3) Under stirring conditions, the aluminate mixed solution was added dropwise to the aluminum salt mixed solution to obtain the precursor solution, and the pH of the precursor solution was adjusted to 9; during the dropwise addition, the aluminum salt mixed solution was heated to 50℃; the dropwise acceleration rate was 11mL / min.

[0078] (4) After the addition is complete, continue stirring for 0.7 h, then raise the temperature to 80℃ and react for 2 h; filter, wash, dry, and calcine the product to obtain the high-efficiency catalyst support material; the calcination temperature is 580℃ and the calcination time is 5 h. The specific surface area of ​​this support material is tested to be 333 m². 2 / g, pore size 18.5nm, pore volume 1.41cm³ 3 / g.

[0079] Example 8

[0080] A method for preparing a high-efficiency catalyst support material includes the following steps:

[0081] (1) Add aluminum salt aluminum nitrate and first hydroxypropyl-β-cyclodextrin to deionized water, and disperse evenly by ultrasonication to obtain an aluminum salt mixed solution; the concentration of aluminum salt in the aluminum salt mixed solution is 12 g / L; the mass ratio of first hydroxypropyl-β-cyclodextrin to aluminum salt is 0.18:1;

[0082] (2) Sodium aluminate, second hydroxypropyl-β-cyclodextrin, and polyethylenepolyamine small molecule compound were added to deionized water to obtain a mixed solution of aluminate; the polyethylenepolyamine small molecule compound was a mixture of diethylenetriamine and triethylenetetramine in a molar ratio of 1:1; the mass ratio of the polyethylenepolyamine small molecule compound to the sum of the masses of first hydroxypropyl-β-cyclodextrin and second hydroxypropyl-β-cyclodextrin was 0.16:1; the mass ratio of aluminate to aluminum salt was 0.75:1; the concentration of aluminate in the mixed solution of aluminate was 7.5 g / L; the mass ratio of second hydroxypropyl-β-cyclodextrin to aluminum salt was 0.08:1;

[0083] (3) Under stirring conditions, the aluminate mixed solution was added dropwise to the aluminum salt mixed solution to obtain the precursor solution, and the pH of the precursor solution was adjusted to 10; during the dropwise addition, the aluminum salt mixed solution was heated to 60℃; the dropwise acceleration rate was 12mL / min.

[0084] (4) After the addition is complete, continue stirring for 0.8 h, then raise the temperature to 85℃ and react for 2.6 h; filter, wash, dry, and calcine the product to obtain a high-efficiency catalyst support material; the calcination temperature is 600℃ and the calcination time is 4.5 h. The specific surface area of ​​this support material is tested to be 335 m². 2 / g, pore size 18.2nm, pore volume 1.38cm³ 3 / g.

[0085] Example 9

[0086] A method for preparing a high-efficiency catalyst support material includes the following steps:

[0087] (1) Add aluminum salt aluminum nitrate and first hydroxypropyl-β-cyclodextrin to deionized water and disperse evenly by ultrasonication to obtain an aluminum salt mixed solution; the concentration of aluminum salt in the aluminum salt mixed solution is 10 g / L; the mass ratio of first hydroxypropyl-β-cyclodextrin to aluminum salt is 0.14:1;

[0088] (2) Sodium aluminate, second hydroxypropyl-β-cyclodextrin, and polyethylenepolyamine small molecule compound were added to deionized water to obtain a mixed solution of aluminate; the polyethylenepolyamine small molecule compound was tetraethylenepentamine; the mass ratio of the polyethylenepolyamine small molecule compound to the sum of the masses of the first hydroxypropyl-β-cyclodextrin and the second hydroxypropyl-β-cyclodextrin was 0.12:1; the mass ratio of aluminate to aluminum salt was 0.6:1; the concentration of aluminate in the mixed solution of aluminate was 7 g / L; the mass ratio of second hydroxypropyl-β-cyclodextrin to aluminum salt was 0.05:1;

[0089] (3) Under stirring conditions, the aluminate mixture solution was added dropwise to the aluminum salt mixture solution to obtain the precursor solution, and the pH of the precursor solution was adjusted to 9; during the dropwise addition, the aluminum salt mixture solution was heated to 53℃; the dropwise acceleration rate was 11mL / min.

[0090] (4) After the addition is complete, continue stirring for 0.8 h, then raise the temperature to 82℃ and react for 2.6 h; filter, wash, dry, and calcine the product to obtain a high-efficiency catalyst support material; the calcination temperature is 570℃ and the calcination time is 5.2 h. The specific surface area of ​​this support material is tested to be 324 m². 2 / g, pore size 17.6nm, pore volume 1.36cm³ 3 / g.

[0091] Example 10

[0092] A method for preparing a high-efficiency catalyst support material includes the following steps:

[0093] (1) Add aluminum salt aluminum nitrate and first hydroxypropyl-β-cyclodextrin to deionized water and disperse evenly by ultrasonication to obtain an aluminum salt mixed solution; the concentration of aluminum salt in the aluminum salt mixed solution is 11 g / L; the mass ratio of first hydroxypropyl-β-cyclodextrin to aluminum salt is 0.15:1;

[0094] (2) Sodium aluminate, second hydroxypropyl-β-cyclodextrin, and polyethylenepolyamine small molecule compound were added to deionized water to obtain a mixed solution of aluminate; the polyethylenepolyamine small molecule compound was a mixture of diethylenetriamine and tetraethylenepentamine in a molar ratio of 2.5:1; the mass ratio of the polyethylenepolyamine small molecule compound to the sum of the masses of first hydroxypropyl-β-cyclodextrin and second hydroxypropyl-β-cyclodextrin was 0.13:1; the mass ratio of aluminate to aluminum salt was 0.7:1; the concentration of aluminate in the mixed solution of aluminate was 7 g / L; the mass ratio of second hydroxypropyl-β-cyclodextrin to aluminum salt was 0.06:1;

[0095] (3) Under stirring conditions, the aluminate mixed solution was added dropwise to the aluminum salt mixed solution to obtain the precursor solution, and the pH of the precursor solution was adjusted to 9; during the dropwise addition, the aluminum salt mixed solution was heated to 50℃; the dropwise acceleration rate was 11mL / min.

[0096] (4) After the addition is complete, continue stirring for 0.7 h, then raise the temperature to 80℃ and react for 2 h; filter, wash, dry, and calcine the product to obtain the high-efficiency catalyst support material; the calcination temperature is 580℃ and the calcination time is 5 h. The specific surface area of ​​this support material is tested to be 339 m². 2 / g, pore size 19.1nm, pore volume 1.44cm³ 3 / g.

[0097] Comparative Example 1

[0098] A method for preparing a high-efficiency catalyst support material includes the following steps:

[0099] (1) Add aluminum salt aluminum nitrate and first β-cyclodextrin to deionized water and disperse evenly by ultrasonication to obtain an aluminum salt mixed solution; the aluminum salt concentration in the aluminum salt mixed solution is 11 g / L; the mass ratio of first β-cyclodextrin to aluminum salt is 0.15:1;

[0100] (2) Sodium aluminate, second β-cyclodextrin, and polyethylene polyamine small molecule compound were added to deionized water to obtain a mixed solution of aluminate; the polyethylene polyamine small molecule compound was a mixture of diethylenetriamine and tetraethylenepentamine in a molar ratio of 2.5:1; the mass ratio of the polyethylene polyamine small molecule compound to the sum of the masses of the first β-cyclodextrin and the second β-cyclodextrin was 0.13:1; the mass ratio of aluminate to aluminum salt was 0.7:1; the concentration of aluminate in the mixed solution of aluminate was 7 g / L; the mass ratio of second β-cyclodextrin to aluminum salt was 0.06:1;

[0101] (3) Under stirring conditions, the aluminate mixed solution was added dropwise to the aluminum salt mixed solution to obtain the precursor solution, and the pH of the precursor solution was adjusted to 9; during the dropwise addition, the aluminum salt mixed solution was heated to 50℃; the dropwise acceleration rate was 11mL / min.

[0102] (4) After the addition is complete, continue stirring for 0.7 h, then raise the temperature to 80℃ and react for 2 h; filter, wash, dry, and calcine the product to obtain a high-efficiency catalyst support material; the calcination temperature is 580℃ and the calcination time is 5 h. The specific surface area of ​​this support material is tested to be 245 m². 2 / g, pore size 13.1nm, pore volume 1.01cm³ 3 / g.

[0103] Comparative Example 2

[0104] A method for preparing a high-efficiency catalyst support material includes the following steps:

[0105] (1) Add aluminum salt aluminum nitrate and first hydroxypropyl-β-cyclodextrin to deionized water and disperse evenly by ultrasonication to obtain an aluminum salt mixed solution; the concentration of aluminum salt in the aluminum salt mixed solution is 11 g / L; the mass ratio of first hydroxypropyl-β-cyclodextrin to aluminum salt is 0.15:1;

[0106] (2) Add sodium aluminate, second hydroxypropyl-β-cyclodextrin, and polyethylenepolyamine small molecule compound to deionized water to obtain a mixed solution of aluminate; the polyethylenepolyamine small molecule compound is a mixture of diethylenetriamine and tetraethylenepentamine in a molar ratio of 2.5:1; the mass ratio of the polyethylenepolyamine small molecule compound to the sum of the masses of first hydroxypropyl-β-cyclodextrin and second hydroxypropyl-β-cyclodextrin is 0.4:1; the mass ratio of aluminate to aluminum salt is 0.7:1; the concentration of aluminate in the mixed solution of aluminate is 7 g / L; the mass ratio of second hydroxypropyl-β-cyclodextrin to aluminum salt is 0.06:1;

[0107] (3) Under stirring conditions, the aluminate mixed solution was added dropwise to the aluminum salt mixed solution to obtain the precursor solution, and the pH of the precursor solution was adjusted to 9; during the dropwise addition, the aluminum salt mixed solution was heated to 50℃; the dropwise acceleration rate was 11mL / min.

[0108] (4) After the addition is complete, continue stirring for 0.7 h, then raise the temperature to 80℃ and react for 2 h; filter, wash, dry, and calcine the product to obtain the high-efficiency catalyst support material; the calcination temperature is 580℃ and the calcination time is 5 h. The specific surface area of ​​this support material is tested to be 258 m². 2 / g, pore size 14.5nm, pore volume 1.08cm³ 3 / g.

[0109] As can be seen from the above examples and comparative examples, the polyethylenepolyamine small molecule compound plays a role in structural regulation and stabilization in this system. It can form hydrogen bonds with numerous hydroxyl groups on the hydroxypropyl-β-cyclodextrin molecule, helping to maintain a small crystallite size. Simultaneously, the polyethylenepolyamine small molecule compound is an organic base with a multidentate ligand, which facilitates the slow and uniform co-precipitation of aluminum salts and aluminates, promoting the formation of alumina pore structures. Furthermore, the nitrogen atoms in the polyethylenepolyamine small molecule compound possess lone pairs of electrons, which can undergo strong complexation with aluminum ions to form stable soluble complexes, promoting the uniform and orderly formation of precursors and contributing to the formation of a more stable framework and more developed pores. In addition, the polyethylenepolyamine small molecule compound itself is a small linear molecule, which can also fill the smaller gaps in the precursor, contributing some smaller mesopores and forming a pore gradation with the macropores generated by hydroxypropyl-β-cyclodextrin, further optimizing the pore structure.

[0110] Specifically, compared to Example 10, Comparative Example 1 used β-cyclodextrin instead of hydroxypropyl-β-cyclodextrin, resulting in a significant decrease in both specific surface area and pore size. This indicates that hydroxypropyl-β-cyclodextrin has a high hydroxyl content and contains hydroxypropyl groups, which not only endows the cyclodextrin with a branched structure but also improves its solubility. This gives hydroxypropyl-β-cyclodextrin a ring structure with an internal lipophilic and external hydrophilic nature, which is more conducive to forming a loose, porous structure and improving the porosity and pore size of the alumina support. In Comparative Example 2, the excessive amount of polyethylenepolyamine small molecule compound caused excessive cross-linking between its nitrogen-containing groups and the hydroxyl groups on hydroxypropyl-β-cyclodextrin due to hydrogen bonding. This hindered the dispersion of the precursor, leading to the formation of a stacked structure and a decrease in the specific surface area of ​​the support material after calcination.

[0111] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for preparing a high efficiency catalyst support material, characterized by, The method comprises the following steps: (1) adding an aluminum salt and a first hydroxypropyl-β-cyclodextrin into deionized water, uniformly dispersing by ultrasonic to obtain an aluminum salt mixed solution; (2) adding a meta-aluminate, a second hydroxypropyl-β-cyclodextrin and a polyethylene polyamine small molecule compound into deionized water to obtain a meta-aluminate mixed solution; the mass ratio of the polyethylene polyamine small molecule compound to the sum of the mass of the first hydroxypropyl-β-cyclodextrin and the mass of the second hydroxypropyl-β-cyclodextrin is (0.05-0.2):1; the polyethylene polyamine small molecule compound is one or more of diethylene triamine, triethylene tetramine, tetraethylene pentamine, pentaethylene hexamine, hexaethylene heptamine, heptaethylene octamine, octaethylene nonamine, nonaethylene decamine and decaethylene undecamine; (3) under stirring, the meta-aluminate mixed solution is added dropwise into the aluminum salt mixed solution to obtain a precursor solution, and the precursor solution is adjusted to be alkaline; (4) after the dropwise addition is completed, the stirring is continued for a period of time, and then the reaction is carried out by heating; after the product is post-treated and calcined, a high-efficiency catalyst carrier material is obtained.

2. The method for preparing a high-efficiency catalyst support material as described in claim 1, characterized in that, In step (1), the aluminum salt is one or more of aluminum nitrate, aluminum chloride, aluminum bromide and aluminum sulfate; the concentration of the aluminum salt in the aluminum salt mixed solution is 8-15 g / L.

3. The method for preparing a high-efficiency catalyst support material as described in claim 1, characterized in that, In step (2), the meta-aluminate is one or more of sodium meta-aluminate or potassium meta-aluminate.

4. The method for preparing a high-efficiency catalyst support material as described in claim 1, characterized in that, In step (2), the mass ratio of the meta-aluminate to the aluminum salt is (0.6-0.8):

1.

5. The method for preparing a high-efficiency catalyst support material as described in claim 1, characterized in that, In step (1), the mass ratio of the first hydroxypropyl-β-cyclodextrin to the aluminum salt is (0.1-0.2):1; in step (2), the mass ratio of the second hydroxypropyl-β-cyclodextrin to the aluminum salt is (0.03-0.1):

1.

6. The method for preparing a high-efficiency catalyst support material as described in claim 1, characterized in that, In step (3), the dropwise addition rate is 8-14 mL / min.

7. The method for preparing a high-efficiency catalyst support material as described in claim 1, characterized in that, In step (4), the stirring time is 0.5-1 h.

8. The method for preparing a high-efficiency catalyst support material as described in claim 1, characterized in that, In step (4), the post-treatment is a filtration, washing and drying process.

9. A high efficiency catalyst support material, characterized by, The high-efficiency catalyst carrier material is prepared by the method in any one of claims 1-8.