Production method of water-resistant spherical silica gel for catalyst carrier

Abstract

The invention discloses a production method of water-resistant spherical silica gel for a catalyst carrier, and belongs to the technical field of new silica gel materials. The method comprises the following steps: taking a sodium silicate aqueous solution or alkoxy silane as a silicon source, mixing the silicon source with a template agent according to a mass ratio of 100: (1-10), adding nano silicon dioxide, and carrying out ultrasonic dispersion to obtain uniform sol; mixing the sol and a non-polar organic solvent according to a volume ratio of 1: (3-8) to form an oil-in-water emulsion, and dropwise adding a promoting solution to form microspheres with an average particle size of 400 [mu] m; mixing the microspheres with a pore expanding agent according to a mass ratio of 1: (8-15), and carrying out hydrothermal reaction to obtain a skeleton; reacting the skeleton with a silicon-based modifier according to a mass ratio of 10: (0.2-1.5); activating by hydrofluoric acid, and grafting a bifunctional coupling agent on the surface; supercritical extraction and thermal activation treatment. The specific surface area of the prepared silica gel is 492.7-533.0 m < 2 > / g, the pore volume is 0.83-1.04 cm < 3 > / g, the pore diameter is 8.2-10.9 nm, the water-resistant strength retention rate is 90.8-94.4%, the compressive strength is 10.7-12.6 MPa, the particle size variation coefficient is 3.1-4.3%, compared with traditional silica gel, the specific surface area of the silica gel is remarkably improved, and the silica gel is suitable for the field of wet catalysis.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of new silica gel materials, and particularly relates to a production method of water-resistant spherical silica gel for catalyst carriers. BACKGROUND

[0002] Silica gel, as an important inorganic material, has a wide application prospect in the field of catalyst carriers. The chemical name of silica gel is silicon dioxide hydrate, and its structure is an amorphous three-dimensional network with high specific surface area, porosity, and good chemical stability. These characteristics make silica gel an ideal catalyst carrier, especially suitable for heterogeneous catalytic reactions in the fields of petroleum and chemical industry, fine chemical industry, environmental protection, and biological catalysis. In the catalyst carrier, the main role of silica gel is to provide a dispersion platform for active components, while ensuring the effective transmission of reactants and products, and maintaining the mechanical and thermal stability of the catalytic system. According to relevant literature reports, the global catalyst market size has exceeded hundreds of billions of dollars, among which the silica gel-based carrier occupies a significant share. However, although the traditional spherical silica gel performs well in dry or non-water environments, it still faces many technical challenges and limitations in actual industrial applications, which directly restricts its promotion and efficiency improvement in wet catalytic reactions.

[0003] The preparation methods of traditional spherical silica gel mainly include sol-gel method, emulsification method, spray drying method, and template method, etc. Among them, the sol-gel method is the most common process, which usually uses sodium silicate or alkoxysilane (such as tetraethyl orthosilicate) as the silicon source, and forms a gel through acid or base catalyzed hydrolysis and polycondensation, and then obtains spherical particles through drying and calcination. For example, early patents such as US2641583A describe a method for preparing silica gel spheres in an oil phase, by dropping silica sol into oil to form spherical particles, but this method easily leads to uneven particles and unstable pore structure. Another typical method is the emulsification method, which mixes silica sol with organic solvent to form an oil-in-water emulsion, and then solidifies into balls by adding a gelling agent (such as acid or salt). Although this method can control the particle morphology, it is often affected by factors such as pH value, ionic strength, and temperature, resulting in complex process and poor repeatability. The spray drying method obtains spherical particles by atomizing silica sol and quickly drying, but this process easily produces hollow or irregular particles, and has high energy consumption. The template method introduces surfactants or polymers as structure directing agents to form ordered mesoporous structures, but traditional templates (such as sodium dodecyl sulfate) are easily collapsed or left with impurities during removal. These preparation methods have been industrialized, but generally have problems such as low yield, high cost, and environmental pollution, such as solvent recovery difficulties and waste acid emissions.

[0004] In terms of performance, the biggest limitation of traditional spherical silica gel lies in its poor water resistance. The surface of silica gel is rich in silicon hydroxyl groups (Si-OH), which are hydrophilic groups that can easily form hydrogen bonds with water molecules in a humid or aqueous environment, leading to the hydrolysis of siloxane bonds (Si-O-Si) and ultimately causing the collapse of the carrier structure and the deactivation of the catalyst. According to research data, the strength retention rate of traditional silica gel is often less than 80% after 24 hours of water immersion, and its service life in wet catalytic reactions (such as hydrogenation or oxidation reactions) is only 1 / 2 to 1 / 3 of that in dry conditions. This not only increases the frequency of catalyst replacement, but also may cause product contamination and safety hazards. For example, in the process of petroleum cracking or wastewater treatment, the presence of water vapor can accelerate the hydrolysis of silica gel, causing bed plugging and pressure fluctuations. Related patents such as CN1522958A mention improving water resistance through acid aging, but the effect is limited, only reducing the hydrolysis rate by about 20%, which cannot meet the high humidity industrial demand. In addition, some literature points out that the poor water resistance of traditional silica gel also stems from its unstable microstructure, with small pore diameters easily filled with water molecules, forming capillary forces that cause collapse.

[0005] Another prominent problem is the low specific surface area. The specific surface area of traditional spherical silica gel is usually less than 400 m 2 / g, and even in some industrial products, it is only 200-300 m 2 / g. This limits the number of active sites, reducing the catalyst loading and reaction efficiency. In heterogeneous catalysis, the specific surface area directly affects mass transfer and reaction rate, for example, in the Fischer-Tropsch synthesis or ammonia synthesis, low specific surface area can result in less than 50% utilization of the catalyst. The reasons for this problem include pore collapse and non-uniform nucleation during preparation. In the traditional sol-gel method, explosive nucleation often produces a dense structure, lacking ordered mesopores. Patent US4617060A discusses the application of small-pore silica gel as a carrier, but acknowledges its transport limitations in catalyst support, making it difficult to accommodate large active components.

[0006] The non-uniformity of pore volume and pore size distribution is also a significant defect of traditional silica gel. The pore volume of traditional products is often less than 0.6 cm 3 / g, with an average pore diameter in the range of 5-7 nm and a wide distribution, containing a large number of micropores and small mesopores. This leads to blocked diffusion of reactants, especially when dealing with large molecules or viscous substances, the problem is more serious. For example, in biocatalysis, enzyme molecules have difficulty entering narrow pore channels, reducing conversion rates. Literature mentions that pore blockage in aldehyde condensation reactions can cause transport limitations, affecting the performance of supported liquid-phase catalysts. Traditional methods such as hydrothermal treatment can expand the pore channels, but may introduce impurities or damage the spherical morphology. Patent JPH04193708A points out that the recovery rate and purity of traditional porous silica gel are low, which cannot meet the high-purity requirements.

[0007] Another constraint is the mechanical weakness. The compressive strength of traditional silica gel is generally less than 8 MPa, which is easy to break or powder in industrial operations (such as fixed bed or fluidized bed), leading to shorter carrier life and dust pollution. This is due to the brittleness and low density of the silica gel skeleton, especially poor stability under high temperature or high pressure conditions. Studies have shown that the strength of traditional silica gel decreases by more than 30% after recycling. Although patent US5229096A describes the preparation of silica gel, it does not solve the problem of mechanical durability. The large particle size variation coefficient (more than 7%) further exacerbates the problem, leading to uneven filling of the catalytic bed, resulting in channeling, hot spots and uneven reaction distribution. In large-scale production, this will increase energy consumption and safety risks.

[0008] The complexity of the traditional preparation process is also worth noting. It involves multiple steps of acidification, aging, washing and drying, with a narrow pH range (usually 4-7), which is easily affected by ionic strength, leading to large batch-to-batch differences. The active components (such as metal oxides) loaded on the surface of the carrier are easy to fall off, further reducing stability. In terms of economy, the traditional method has low raw material utilization rate (<70%) and generates a large amount of wastewater, which puts a lot of pressure on environmental protection. These shortcomings seriously restrict the application of spherical silica gel in the field of wet reaction, such as hydrodesulfurization in petroleum chemical industry, selective oxidation in fine chemical industry, enzyme immobilization in biocatalysis, and wastewater treatment in environmental catalysis. In these fields, the wet environment requires the carrier to have high water resistance and stability, but traditional silica gel is difficult to meet the requirements, leading the industry to rely on imported high-end products or switch to other carriers such as activated carbon or alumina, which are water-resistant but have low specific surface area (<200 m 2 / g) and poor thermal conductivity.

[0009] In recent years, although there have been some improvement attempts, such as the introduction of aluminum silica gel or carbon-silicon composite materials to improve water resistance, these methods still have limitations. For example, patent CN105060311A proposes waterproof modification of hydrophilic silica gel, but only from the perspective of skeleton strength and hydrophobic groups, it is impossible to achieve gradient control. Other developments such as mesoporous silica gel nanocarriers have improved drug delivery, but the catalytic field still faces pore blockage and stability problems. Overall, existing improvements are difficult to fully address the multiple defects of traditional silica gel, and a new production method is urgently needed to combine nanoseed regulation, pore expansion, in-situ modification and supercritical extraction technologies to achieve spherical silica gel carriers with high specific surface area, large pore volume, uniform pore size, excellent water resistance and high mechanical strength.

[0010] In summary, the limitations of traditional spherical silica gel catalyst carriers are due to the inherent defects of their microstructure, surface properties and preparation process, which not only affect the catalytic efficiency and service life, but also restrict the expansion of industrial applications. With the growing demand for wet catalysis (such as green chemistry and renewable energy fields), the development of water-resistant high-performance silica gel carriers has become a consensus in the industry. The present invention is aimed at these technical bottlenecks and proposes an innovative production method to fill the gaps in existing technology and promote the development of high-end silica gel materials. SUMMARY

[0011] Traditional spherical silica gel for catalyst carriers has many limitations in practical applications, mainly manifested in poor water resistance, easy hydrolysis and disintegration in humid or aqueous environments, leading to carrier structure damage and rapid loss of catalyst activity; low specific surface area, unable to provide enough active sites, limiting catalyst loading and reaction efficiency; small pore volume and uneven pore size distribution, affecting reactant diffusion and product transport, easily causing pore blockage; insufficient mechanical strength, easily broken or powdered in industrial operations, shortening service life; large particle size variation coefficient, leading to uneven filling of the catalytic bed, causing channeling or hot spot problems. In addition, the traditional preparation process is complex, involving multiple steps of acidification, aging, etc., with a narrow pH range, easily affected by ionic strength, and the active components loaded on the carrier surface are easy to fall off, further reducing the stability and economy of the catalyst. These shortcomings seriously restrict the widespread application of spherical silica gel in wet reaction fields such as petrochemicals, fine chemicals, biological catalysis and environmental catalysis, and it is urgent to develop new water-resistant high-performance carriers to overcome the above technical bottlenecks.

[0012] To solve the above problems, the technical scheme adopted by the present invention is as follows.

[0013] A production method of a water-resistant spherical silica gel for catalyst carrier, comprising the following steps: (1) preparation of nano seed sol: mixing sodium silicate (CAS No. 1344-09-8) aqueous solution or alkoxysilane as a silicon source with at least one template selected from cetyltrimethylammonium chloride (CAS No. 112-02-7), polyethylene glycol (CAS No. 25322-68-3) or block copolymer F127 (CAS No. 9003-11-6) in a mass ratio of 100: (1-10), while adding nano silica and ultrasonic dispersion treatment to obtain a uniform nano seed sol; (2) preparation of gel microspheres: mixing the nano seed sol obtained in step (1) with a non-polar organic solvent in a volume ratio of 1: (3-8) to obtain an oil-in-water emulsion, and then adding a promoting liquid dropwise to the oil-in-water emulsion to form gel microspheres with an average particle size of 400 μm; (3) preparation of silica gel framework: mixing the gel microspheres obtained in step (2) with a pore extender in a mass ratio of 1: (8-15), and then performing hydrothermal reaction to obtain spherical silica gel framework; (4) in-situ modification reaction: performing in-situ modification reaction of the silica gel framework obtained in step (3) with a silicon-based modifier in a mass ratio of 10: (0.2-1.5) to obtain a preliminary product; (5) gradient hydrophilic-hydrophobic regulation: performing activation treatment of the preliminary product obtained in step (4) with a hydrofluoric acid (CAS No. 7664-39-3) solution in a mass ratio of 1: (2-5), and then adding an ethanol solution containing a bifunctional coupling agent to the preliminary product in an amount of 0.2-0.8 times the mass of the preliminary product for surface grafting to obtain microspheres with gradient hydrophilic-hydrophobic property; (6) supercritical extraction: performing supercritical extraction of the microspheres obtained in step (5), and finally performing thermal activation treatment to obtain a final product.

[0014] Preferably, the modulus of the sodium silicate aqueous solution in step (1) is 1.5-3.5, and the mass percentage is 5%-15%; the alkoxysilane in step (1) is tetraethyl orthosilicate, tetramethyl orthosilicate, methyltrimethoxysilane, methyltriethoxysilane, phenyltriethoxysilane, dodecyltriethoxysilane, 3-aminopropyltriethoxysilane or γ-glycidoxypropyltrimethoxysilane.

[0015] The CAS No. of tetraethyl orthosilicate is 78-10-4; the CAS No. of tetramethyl orthosilicate is 681-84-5; the CAS No. of methyltrimethoxysilane is 1185-55-3; the CAS No. of methyltriethoxysilane is 2031-67-6; the CAS No. of phenyltriethoxysilane is 780-69-8; the CAS No. of dodecyltriethoxysilane is 18536-91-9; the CAS No. of 3-aminopropyltriethoxysilane is 919-30-2; and the CAS No. of γ-glycidoxypropyltrimethoxysilane is 2530-83-8.

[0016] Preferably, the particle size of the nanosilica in step (1) is 5-20 nm, and the amount of the nanosilica is 0.5-3.0% of the mass of the silicon source; the parameters of the ultrasonic dispersion treatment in step (1) are as follows: 5-20℃, 600-1000W, 40-80kHz and 15-45min.

[0017] Preferably, the non-polar organic solvent in step (2) is cyclohexane (CAS No. 110-82-7) or n-hexane (CAS No. 110-54-3); the parameters of the mixing in step (2) are as follows: rotation speed 8000-15000rpm; the promoting liquid in step (2) is obtained by mixing triethylamine (CAS No. 121-44-8), acetic acid (CAS No. 64-19-7), zirconium n-propylate (CAS No. 23519-77-9) and ethanol according to the mass ratio (0.8-2):(1-3):(2-6):(10-20); the rate of the dropwise addition in step (2) is controlled to be 0.5-2.0mL / min, and the pH value after the dropwise addition is completed is controlled to be 4.0-6.5.

[0018] Preferably, the pore extender in step (3) is an alcohol-water mixed solution containing organic amines, wherein the alcohol-water mixed solution is a mixed solution of alcohol and water according to the mass ratio 1:(2-5), wherein the alcohol is ethanol, n-propanol, isopropanol, n-butanol, isobutanol, tert-butanol, n-pentanol, ethylene glycol, glycerol or cyclohexanol, and wherein the organic amines are 0.2-0.4 times the mass of the alcohol-water mixed solution, and wherein the organic amines are urea (CAS No. 57-13-6), methylamine (CAS No. 74-89-5) or ethylenediamine (CAS No. 107-15-3).

[0019] Preferably, the parameters of the hydrothermal reaction in step (3) are as follows: 120-220℃, 1.5-4MPa and 12-18h.

[0020] Preferably, the silicon-based modifying agent in step (4) is trimethylchlorosilane (CAS No. 75-77-4), hexamethyldisilazane (CAS No. 999-97-3), vinyltriethoxysilane (CAS No. 78-08-0) or 3-mercaptopropyltrimethoxysilane (CAS No. 4420-74-0); the parameters of the in-situ modification reaction in step (4) are as follows: 50-80℃, 10-20MPa and 4-8h.

[0021] Preferably, the mass percentage of the hydrofluoric acid solution in step (5) is 0.5-2%; the parameters of the activation treatment in step (5) are as follows: 25-40℃ and 80-120min; the bifunctional coupling agent in step (5) is 3-aminopropyltriethoxysilane (CAS No.: 919-30-2), 3-mercaptopropyltrimethoxysilane (CAS No.: 4420-74-0) or vinyltriethoxysilane (CAS No.: 78-08-0); the mass percentage of the bifunctional coupling agent in the ethanol solution in step (5) is 1-5%; the parameters of the surface grafting in step (5) are as follows: 60-80℃ and 8-12h.

[0022] Preferably, the parameters of the supercritical extraction in step (6) are as follows: 35-60℃, 12-20MPa and 6-10h; the parameters of the thermal activation treatment in step (6) are as follows: heating to 450-750℃ at a heating rate of 5-15℃ / min, and calcining in nitrogen for 6-10h.

[0023] Overall: Template mechanism: Cetyltrimethylammonium bromide, polyethylene glycol or block copolymer F127 as a structure-directing agent, by self-assembly to form micelles, provide a template for ordered mesoporous structure. Nanosilica seed effect: 5-20 nm nanosilica as nucleation point, reduce the nucleation energy barrier, promote uniform nucleation, avoid burst nucleation leading to uneven particle size. Ultrasonic dispersion mechanism: 600-1000 W, 40-80 kHz ultrasonic cavitation effect breaks the agglomerates, forming a uniform seed sol. Gel microsphere formation mechanism: Emulsion stability mechanism: In the oil-in-water emulsion system, the silicon source is in the water phase, and the non-polar solvent forms the dispersed phase, high-speed shearing produces uniform droplets; promote liquid catalytic mechanism: triethylamine provides an alkaline environment to promote silicic acid polycondensation; acetic acid adjusts the pH value to control the gel rate; zirconium n-propyl alcohol as Lewis acid catalyst to accelerate Si-O-Si bond formation; ethanol improves system compatibility; pH control mechanism: In the range of pH 4.0-6.5, silicic acid is near the isoelectric point, which is conducive to controlling the polycondensation rate and forming uniform 400 μm microspheres. Pore expansion mechanism: Organic amine pore expansion mechanism: Urea, methylamine or ethylenediamine decomposes to produce NH3 under hydrothermal conditions, which enters the silica gel framework as a pore expander, while its alkalinity promotes Si-O-Si bond rearrangement; hydrothermal restructuring mechanism: Under the conditions of 120-220 ℃ and 1.5-4 MPa, the silica gel framework is cured, small pores are dissolved and large pores are grown, forming uniform mesopores of 8-12 nm. Gradient hydrophilic-hydrophobic regulation mechanism: In-situ modification mechanism: The silicon-based modifier reacts with the Si-OH on the surface of the silica gel to form Si-O-Si-R hydrophobic groups, forming a gradient distribution from the inside to the outside. Hydrofluoric acid activation mechanism: 0.5-2% HF selectively etches the surface to increase the Si-OH active sites, providing reaction sites for subsequent grafting. Dual-functional group grafting mechanism: 3-aminopropyl triethoxysilane, etc. are bonded to the silica gel through one end and the other end functional group regulates the hydrophilic-hydrophobic balance. Supercritical extraction enhancement mechanism: Capillary force elimination: The density of supercritical CO2 is between gas and liquid, and the surface tension is close to zero, avoiding the collapse of traditional drying capillary force. Thermal activation and solidification: 450-750 ℃ nitrogen calcination promotes complete condensation of Si-O-Si bond, strengthening the framework structure.

[0024] Compared with the prior art, the beneficial effects of the present application are: significant improvement in structural performance: ultra-high specific surface area: up to 492.7-533.0 m 2 / g, about 63% higher than traditional silica gel, providing more active sites for catalysts; large pore volume design: 0.83-1.04 cm 3 / g, about 77% increase, enhanced catalyst loading and reactant transport capacity; ideal pore size distribution: 8.2-10.9 nm uniform mesopore, suitable for macromolecular catalyst access and product diffusion. Breakthrough in water resistance stability: gradient hydrophobic protective layer: form a gradient hydrophilic-hydrophobic structure from inside to outside by in-situ modification and surface grafting, strength retention rate reaches 90.8-94.4% after 24 hours of water immersion, about 27% higher than traditional silica gel, hydrolysis mechanism: hydrophobic groups shield Si-O-Si bonds, inhibit water molecule attack, solve the problem of easy disintegration of traditional silica gel in wet catalysis. Excellent mechanical properties: high compressive strength: 10.7-12.6 MPa, about 60% increase, meet the durability requirements of industrial catalyst carriers, highly uniform particle size: coefficient of variation is only 3.1-4.3%, ensure uniform filling of the catalytic bed, avoid channeling and hot spots. Process innovation advantage: nano-seed regulation technology: for the first time, nano-silica seeds are introduced into silica gel preparation, realizing precise control of nucleation and growth, multi-step synergistic effect: synergy of template self-assembly, promoting liquid catalysis, hydrothermal pore expansion, gradient modification and supercritical extraction, indispensable. Outstanding application value: extend catalyst life: in petroleum chemical industry, fine chemical industry and other wet catalytic reactions, the expected service life is increased by 2-3 times; broaden application fields: suitable for water phase catalysis, biological catalysis, environmental protection catalysis and other fields with high requirements for water resistance of carriers; economic and environmental benefits: raw materials are easy to obtain, process is controllable, supercritical extraction reduces organic solvent emissions, in line with the development direction of green chemical industry. Technical breakthrough significance: fill the technical gap: solve the industry problem of poor water resistance of spherical silica gel catalyst carriers, provide an ideal carrier for catalytic reactions in high humidity environments; promote industrial upgrading: provide technical support for the high-end development of catalyst carrier materials in China, break the monopoly of foreign technology. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a transmission electron microscope image of the nano-seed sol prepared in Example 1.

[0026] Figure 2 is a scanning electron microscope image of the gel microspheres prepared in Example 1.

[0027] Figure 3 is a transmission electron microscope image of the water-resistant spherical silica gel prepared in Example 1. DETAILED DESCRIPTION

[0028] The application will be described in detail below through specific examples, but the purpose and purpose of these exemplary embodiments are only used to exemplify the application, and do not constitute any form of any limitation on the actual protection scope of the application, nor does it limit the protection scope of the application. For the range of parameters not mentioned, the intermediate value is selected. At the same time, for the mass percentage or weight percentage not explicitly stated or mentioned, it generally refers to the final concentration after addition.

[0029] Example 1

[0030] Preparation of nanoseed sol: Take sodium silicate aqueous solution (modulus is 2.5, mass percentage is 10%, total amount of silicon source is 1000g) as silicon source, mix with template agent hexadecyl trimethyl ammonium chloride (CAS No. 112-02-7) according to mass ratio 100:5, at the same time add nanosilica (particle size is 12nm, amount is 1.75% of the mass of silicon source, i.e. 17.5g), ultrasonic dispersion treatment at temperature 12℃, power 800W, frequency 60kHz for 30min, to obtain uniform nanoseed sol, the microstructure of which is shown in Figure 1 Preparation of gel microspheres: mix the obtained nanoseed sol with non-polar organic solvent cyclohexane (CAS No. 110-82-7) according to volume ratio 1:5.5, at rotating speed 11500rpm, to obtain oil-in-water emulsion. Subsequently, add promoting liquid (promoting liquid is obtained by mixing triethylamine (CAS No. 121-44-8), acetic acid (CAS No. 64-19-7), zirconium n-propyl alcohol (CAS No. 23519-77-9) and ethanol according to mass ratio 1.4:2:4:15, total amount is appropriate proportion of emulsion mass to regulate pH) dropwise to the oil-in-water emulsion, control the dropwise rate to be 1.25mL / min, after the dropwise addition is completed, control the pH value to be 5.25, to form gel microspheres with average particle size 400μm, as shown in Figure 2The obtained gel microspheres were mixed with a pore extender in a mass ratio of 1 : 11.5 (the pore extender was an alcohol-water mixed solution containing organic amines, wherein the alcohol-water mixed solution was a mixed solution of ethanol and water in a mass ratio of 1 : 3.5, and the organic amines were urea (CAS No. 57-13-6) in an amount of 0.3 times the mass of the alcohol-water mixed solution), followed by hydrothermal reaction (temperature 170°C, pressure 2.75 MPa, time 15 h) to obtain spherical silica gel skeletons. In-situ modification reaction: the obtained silica gel skeletons were subjected to in-situ modification reaction with a silicon-based modifier trimethylchlorosilane (CAS No. 75-77-4) in a mass ratio of 10:0.85 (temperature 65°C, pressure 15 MPa, time 6 h) to obtain a preliminary product. Gradient hydrophilic-hydrophobic regulation: the obtained preliminary product was activated with a hydrofluoric acid (CAS No. 7664-39-3) solution (mass percentage 1.25%) in a mass ratio of 1 : 3.5 (temperature 32°C, time 100 min), followed by surface grafting with an ethanol solution containing a bifunctional coupling agent (the bifunctional coupling agent was 3-aminopropyltriethoxysilane (CAS No. 919-30-2) in an ethanol solution with a mass percentage of 3%) in an amount of 0.5 times the mass of the preliminary product (temperature 70°C, time 10 h) to obtain microspheres with gradient hydrophilic-hydrophobic properties. Supercritical extraction: the obtained microspheres were subjected to supercritical extraction (temperature 47°C, pressure 16 MPa, time 8 h), followed by heat activation treatment (heated to 600°C at a heating rate of 10°C / min and calcined in nitrogen for 8 h) to obtain the final product, as shown in FIG. 1. Figure 3

[0031] Example 2-20

[0032] ​Example 2-20 Reference to the process flow of Example 1, adjust some parameters. In order to verify the necessity of key components and technical conditions, the following comparative examples were designed. By missing key components (such as template agent, nano-silica, internal components of promoting liquid, internal organic amine of channel expander, silicon-based modifier, bifunctional coupling agent) or exceeding parameter range, replacing with other commonly used similar components (such as replacing cetyl trimethyl ammonium chloride with dodecyl trimethyl ammonium chloride, replacing urea with triethylamine, replacing trimethyl chlorosilane with dimethyl dichlorosilane), the disadvantages were embodied. Comparative Example 1: Different from Example 1, no template agent was added, and the remaining steps were the same as Example 1. Comparative Example 2: Different from Example 1, no nano-silica was added, and an equivalent amount of silica source was used instead, and the remaining steps were the same as Example 1. Comparative Example 3: Different from Example 1, no zirconium n-propyl alcohol was added in the promoting liquid, and an equivalent amount of ethanol was used instead, and the remaining steps were the same as Example 1. Comparative Example 4: Different from Example 5, no internal organic amine of channel expander (urea) was added, and the remaining steps were the same as Example 5. Comparative Example 5: Different from Example 5, no silicon-based modifier was added, and the remaining steps were the same as Example 5. Comparative Example 6: Different from Example 5, no bifunctional coupling agent was added, and an equivalent amount of ethanol solution was used instead, and the remaining steps were the same as Example 5. Comparative Example 7: Different from Example 8, the template agent was replaced with dodecyl trimethyl ammonium chloride (CAS No.: 112-00-5), and the remaining steps were the same as Example 8. Comparative Example 8: Different from Example 8, the organic amine was replaced with triethylamine (CAS No.: 121-44-8, non-conventional application substance), and the remaining steps were the same as Example 8. Comparative Example 9: Different from Example 8, the silicon-based modifier was replaced with dimethyl dichlorosilane (CAS No.: 75-78-5), and the remaining steps were the same as Example 8. Comparative Example 10: Different from Example 10, the modulus of sodium silicate aqueous solution was 4.0 (exceeding the required range of 1.5-3.5), and the remaining steps were the same as Example 10. Comparative Example 11: Different from Example 10, the particle size of nano-silica was 3 nm (lower than the required range of 5-20 nm), and the remaining steps were the same as Example 10. Comparative Example 12: Different from Example 10, the volume ratio of nano-seed sol to non-polar organic solvent was 1:2 (lower than the required range of 1:3-8), and the remaining steps were the same as Example 10. Comparative Example 13: Different from Example 12, the dropping speed of promoting liquid was 3.0 mL / min (exceeding the required range of 0.5-2.0 mL / min), and the remaining steps were the same as Example 12. Comparative Example 14: Different from Example 12, the hydrothermal reaction temperature was 100℃ (lower than the required range of 120-220℃), and the remaining steps were the same as Example 12. Comparative Example 15: Different from Example 12, the in-situ modification reaction pressure was 5 MPa (lower than the required range of 10-20 MPa), and the remaining steps were the same as Example 12. Comparative Example 16: Different from Example 15, the mass percentage of hydrofluoric acid solution was 3% (exceeding the required range of 0.5-2%), and the remaining steps were the same as Example 15.Comparative Example 17: Unlike Example 15, the surface grafting temperature was 90 °C (outside the required range of 60-80 °C), and the remaining steps were the same as Example 15. Comparative Example 18: Unlike Example 15, the supercritical extraction pressure was 10 MPa (lower than the required range of 12-20 MPa), and the remaining steps were the same as Example 15. Comparative Example 19: Unlike Example 18, the heating rate of the thermal activation process was 3 °C / min (lower than the required range of 5-15 °C / min), and the remaining steps were the same as Example 18. Comparative Example 20: Unlike Example 18, the mass ratio of gel microspheres to pore expander was 1:20 (outside the required range of 1:8-15), and the remaining steps were the same as Example 18.

[0033] Table 1 Formulation and process parameters of Examples 1-7

[0034]

[0035] Table 1 demonstrates the high controllability and robustness of the present invention in the initial stage of production. By systematically combining and verifying all key parameters such as raw material selection, dispersion conditions, emulsification system, and gelation process, it is proven that this method can stably produce high-quality uniform sol and gel microspheres as the basis for subsequent steps.

[0036] Table 2 Formulation and process parameters of Examples 1-7

[0037]

[0038] Table 2 demonstrates that through the fine and systematic control of a series of complex steps such as pore expansion, internal modification, surface grafting, supercritical drying, and high-temperature calcination, revolutionary spherical silica gel materials with high specific surface area, large pore volume, excellent water resistance, and high mechanical strength can be stably manufactured.

[0039] In summary, Tables 1 and 2 above collectively demonstrate a complete "design-manufacturing" process of the present patent method. By systematically changing the key parameters of each step, the flexibility, robustness, and high controllability of the production method are fully verified.

[0040] Specifically, a complete and highly detailed process flow is demonstrated. It is proven that the patented method is not dependent on a fixed recipe, but a flexible and powerful platform technology. By systematically and synergistically regulating each step from raw material selection to final calcination, revolutionary spherical silica gel materials with high specific surface area, large pore volume, excellent water resistance and high mechanical strength can be stably produced. Table 1 relates to the preparation of initial raw materials and gel microspheres, which is the basis of the entire process, aiming to prepare high-quality and uniform gel microsphere precursors through precise control. Table 2 relates to structure shaping and performance enhancement, which is the core of the process, through a series of complex physical and chemical treatments, the preliminary gel microspheres are converted into the final high-performance product.

[0041] Table 3 Formulation and process parameters of examples 8-14

[0042]

[0043] In combination with Table 3, not only is it a repeated verification of the patented process parameters, but also an expansion of its application boundaries. By successfully integrating a variety of functional organosilanes and new pore-expanding solvents into the process flow.

[0044] This table strongly proves that the patented method is a highly flexible platform technology that can accommodate a wide range of chemical raw materials, providing a solid technical foundation for the preparation of customized silica gel materials with specific functions and excellent structures. At the same time, Table 3 mainly relates to the optimization and improvement of silicon sources and template agents, which are related to the performance of the overall final product.

[0045] Table 4 Formulation and process parameters of examples 8-14

[0046]

[0047] Table 4 lists the key process parameters used in the second half of the production process for examples 8-14. These steps are the core of giving the final product excellent water resistance, high mechanical strength and fine surface function.

[0048] Table 5 Formulation and process parameters of examples 15-20

[0049]

[0050] Table 6 Formulation and process parameters of examples 15-20

[0051]

[0052]

[0053] Table 5 and Table 6 demonstrate Examples 15-20 as the last group of verification experiments, by systematic cycling and combination of the aforementioned multiple raw materials and process parameters, strongly prove the universality and high stability of the patent method. No matter what starting raw materials or process parameter combinations (within the scope of patent limitations) are used, the method can stably guide the product to the preset high-performance target. This fully shows that the present application is not an isolated formula, but a mature, flexible and reliable platform technology that can be used for large-scale production of advanced spherical silica gel materials with high specific surface area, large pore volume, excellent water resistance and high mechanical strength.

[0054] Table 7 Formulation and process parameters of Comparative Examples 1-7

[0055]

[0056] Table 8 Formulation and process parameters of Comparative Examples 1-7

[0057]

[0058] As shown in Table 7 and Table 8, it is systematically proved that each core technical point of the present patent application - from the selection of the template agent and the seed, to the use of the pore expander, the modifier and the coupling agent - is the key to achieving the excellent performance (high specific surface area, large pore volume, strong water resistance) of the final product. The subsequent performance test results will show that any omission or improper replacement of these key elements will result in a significant decline in product performance.

[0059] Table 9 Formulation and process parameters of Comparative Examples 8-14

[0060]

[0061] Table 10 Formulation and process parameters of Comparative Examples 8-14

[0062]

[0063]

[0064] Table 11 Formulation and process parameters of Comparative Examples 8-14

[0065]

[0066] As can be seen from Tables 9, 10 and 11, the innovativeness and advancement of the present patent technology are irrefutably proved from two dimensions (the particularity of raw material selection and the accuracy of process parameters). They collectively show that the present application is not a simple step stacking, but an optimized system with each link tightly coupled and synergistic. Any seemingly small deviation or replacement will destroy this synergistic effect.

[0067] Table 12 Formulation and process parameters of Comparative Examples 15-20

[0068]

[0069] Table 13 Formulation and process parameters of Comparative Examples 15-20

[0070]

[0071] From Tables 12 and 13, it can be seen that Comparative Examples 15-20, through a series of meticulous “single variable error” experiments, have irrefutably proven that each of the process parameter ranges defined in this patent are the best intervals obtained after a large number of experiments.

[0072] To comprehensively evaluate the performance of water-resistant spherical silica gel for catalyst carriers, the following test methods are designed, covering key indicators such as specific surface area, pore volume, average pore size, water resistance, mechanical strength, and particle size uniformity.

[0073] Test methods refer to national standards (such as “Silica Gel Catalyst Carrier Performance Test Method” GB / T30807-2014 and “Porous Material Specific Surface Area and Pore Size Distribution Determination Method” GB / T19587-2017) to ensure scientific and reasonable results.

[0074] Specific Surface Area (m 2 / g) Test Method: BET nitrogen adsorption method, using an automatic specific surface area analyzer. After sampling, vacuum degassing at 200°C for 4h, nitrogen adsorption temperature is -196°C, relative pressure range 0.05-0.3. Significance: Evaluate the surface activity of silica gel, target value >400m 2 / g.

[0075] Pore Volume (cm 3 / g) Test Method: BJH desorption method, based on nitrogen adsorption isotherm to calculate total pore volume. Test conditions are the same as specific surface area test. Significance: Reflects the pore capacity of silica gel, target value >0.8cm 3 / g.

[0076] Average Pore Size (nm) Test Method: BJH method to calculate the average value of pore size distribution. Test conditions are the same as above. Significance: Evaluate the uniformity of pore size, target value 8-12nm.

[0077] Water Resistance (%) Test Method: Soak silica gel samples in distilled water for 24h, measure the mechanical strength retention rate after drying (strength after soaking / initial strength x 100%). Test conditions: Room temperature 25°C, water to silica gel mass ratio 10:1. Significance: Reflects water resistance stability, target value >90%.

[0078] Mechanical strength (MPa) Test method: The compressive strength of spherical silica gel was determined by a universal material testing machine. The sample with an average particle size of 400 pm was loaded at a rate of 0.5 mm / min. Significance: To evaluate the mechanical durability of the carrier, the target value is >10 MPa.

[0079] Particle size uniformity (%) Test method: The particle size distribution was determined by a laser particle size analyzer, and the coefficient of variation (standard deviation / average particle size x 100%) was calculated. Test conditions: The dispersion medium was ethanol, and the sample concentration was 0.1%. Significance: To reflect the uniformity of the microspheres, the target value is <5%.

[0080] The performance test results of Examples 1-20 and Comparative Examples 1-20 are as follows, with units as described above.

[0081] Meanwhile, the performance test results of Examples 1-20 and Comparative Examples 1-20 are analyzed and summarized.

[0082] Table 14 Performance test results of Examples 1-10

[0083]

[0084] Table 15 Performance test results of Examples 11-20

[0085]

[0086] In combination with Tables 14 and 15, these data evaluate the product performance of the water-resistant spherical silica gel for catalyst carriers under different process parameters, covering six key indicators: specific surface area (m 2 / g), pore volume (cm 3 / g), average pore size (nm), water resistance (%), mechanical strength (MPa), and particle size uniformity (%). The test methods refer to national standards, such as GB / T 19587-2017 (BET nitrogen adsorption method for specific surface area and pore structure) and GB / T 30807-2014 (Performance test of catalyst carriers, including water resistance and mechanical strength). The 20 examples represent the optimized combination of variables such as silica source, template agent, and ultrasonic parameters, aiming to verify the stability and excellence of the method. Overall, the product performance of all examples is significantly better than that of traditional silica gel (specific surface area <400 m 2 / g, water resistance <80%, etc.), reflecting the synergistic effect of processes such as nano-seed regulation, hydrothermal pore expansion, in-situ modification, and supercritical extraction.

[0087] Table 16 Performance test results of Comparative Examples 1-10

[0088]

[0089] Table 17 Performance test results of Comparative Examples 11-20

[0090]

[0091] From Table 16 and Table 17, these data evaluated the comparative performance of the production method of catalyst support with water-resistant spherical silica gel under missing key components, exceeding parameter ranges or replacing components, covering six key indicators: specific surface area (m 2 / g), pore volume (cm 3 / g), average pore size (nm), water resistance (%), mechanical strength (MPa) and particle size uniformity (%). Test methods are the same as examples, refer to GB / T19587-2017 (BET nitrogen adsorption method) and GB / T30807-2014 (water resistance and strength test). The 20 comparative examples aim to verify the necessity of the process, such as no template (comparative example 1), no nano-silica (comparative example 2), parameter over-limit (such as modulus 4.0, comparative example 10) or replacement (such as replacing urea with triethylamine, comparative example 8). Overall, the performance of comparative examples is significantly worse than examples, with an average decrease of 30-50%, highlighting the indispensability of steps such as nano-seed sol preparation, gel microsphere formation, hydrothermal pore expansion, in-situ modification, gradient hydrophilic-hydrophobic regulation and supercritical extraction.

[0092] In summary, the present application provides a new production method, through steps such as nano-seed sol preparation, gel microsphere formation, hydrothermal reaction, in-situ modification, gradient hydrophilic-hydrophobic regulation and supercritical extraction, to prepare high-performance water-resistant spherical silica gel. As a catalyst support, this silica gel has high specific surface area, large pore volume, uniform pore size, excellent water resistance, high mechanical strength and good particle size uniformity. Compared with existing technologies (such as traditional silica gel support easy to disintegrate, poor water stability, uneven pore structure), the present application solves the problems of easy hydrolysis of silica gel in humid environment, low mechanical strength and pore blockage, significantly improving the stability and efficiency of the catalyst support. Test results show that the performance of example products is better than that of comparative examples (comparative examples missing key components, exceeding parameter ranges or replacing components, leading to a 30-50% decrease in performance), proving the necessity and synergistic effect of the process.

[0093] Based on standard methods such as BET nitrogen adsorption method, BJH method, immersion test, universal material testing machine and laser particle size analysis (refer to GB / T30807-2014 and GB / T19587-2017), the performance comparison of examples and comparative examples is as follows (data is average range): specific surface area (m 2 / g): examples: 492.7-533.0 m 2 / g (average about 515 m 2 / g). Comparative examples: 291.5-334.0 m 2 / g (average about 315 m 2 / g). Advantages: Increased by approximately 63%, providing greater surface activity, promoting catalyst loading and reaction efficiency. Reason: The nano-seed sol and pore expander synergistically form an ordered mesoporous structure, avoiding the pore collapse of traditional methods. Pore volume (cm 3 / g): Example: 0.83-1.04cm 3 / g (average of about 0.94cm 3 / g). Comparative example: 0.46-0.59cm 3 / g (average of about 0.53cm 3Advantage: ~77% improvement, enhanced mass transport and loading capacity. Reason: Hydrothermal reaction (120-220℃, 1.5-4MPa) and organic amine extender effectively expand the pores, avoiding blockage. Average pore size (nm): Example: 8.2-10.9nm (average ~9.6nm). Comparative: 5.7-7.1nm (average ~6.4nm). Advantage: ~50% improvement, achieving uniform mesopore distribution, facilitating the entry of macromolecular catalysts. Reason: Promoting liquid (containing zirconium n-propyl alcohol, etc.) and ultrasonic dispersion ensure uniform seeding, forming an ideal pore structure. Water resistance (%) (strength retention rate after 24h water immersion): Example: 90.8-94.4% (average ~92.8%). Comparative: 69.7-75.6% (average ~72.8%). Advantage: ~27% improvement, significantly improving water stability, suitable for wet catalytic environment. Reason: In-situ modification (silicon-based modifier) and gradient hydrophilic-hydrophobic regulation (hydrofluoric acid activation + bifunctional group grafting) form a gradient hydrophobic layer, inhibiting hydrolytic collapse. Mechanical strength (MPa) (compressive strength): Example: 10.7-12.6MPa (average ~11.7MPa). Comparative: 6.6-7.9MPa (average ~7.3MPa). Advantage: ~60% improvement, enhancing durability, reducing carrier fragmentation. Reason: Supercritical extraction (35-60℃, 12-20MPa) and thermal activation (450-750℃ calcination) strengthen the framework structure. Particle size uniformity (%) (coefficient of variation): Example: 3.1-4.3% (average ~3.7%). Comparative: 7.5-9.3% (average ~8.3%). Advantage: ~55% reduction, achieving uniform spherical microspheres with an average particle size of 400μm, facilitating industrial filling and flow. Reason: Oil-in-water emulsion (sol: solvent volume ratio 1:3-8) and controlled dropping (0.5-2.0mL / min, pH 4.0-6.5) ensure consistent morphology. Process innovation points and synergistic effects: Core innovation: Introduction of nano-silica seeds (5-20nm, 0.5-3.0% dosage) and template agents (mass ratio 100:1-10), combined with promoting liquid (containing zirconium n-propyl alcohol) and pore extender (containing organic amine such as urea), realizing self-assembly to form an ordered framework; in-situ modification and gradient regulation impart gradient hydrophilic-hydrophobicity; supercritical extraction avoids the capillary force damage of traditional drying. Synergistic advantage: Missing key components (such as Comparative Example 1 without template agent, Comparative Example 2 without nano-silica, Comparative Example 3 without zirconium n-propyl alcohol) leads to a 40-50% performance decline; exceeding parameter range (such as Comparative Example 10 with a modulus of 4.0, Comparative Example 13 with a dropping rate of 3.0mL / min) or replacing components (such as Comparative Example 7 using dodecyltrimethylammonium chloride, Comparative Example 9 using dimethyldichlorosilane) causes pore structure collapse and reduced water resistance. The example achieves overall performance improvement through parameter optimization (such as ultrasonic 600-1000W, 40-80kHz).Economic and environmental benefits: simple and controllable method, using common raw materials (such as sodium silicate, alkoxysilane), supercritical extraction reduces organic solvent waste, suitable for large-scale production. Application value: as catalyst carrier: high specific surface area and large pore volume improve loading efficiency; excellent water resistance and mechanical strength extend service life (expected to increase stability by 2-3 times in wet reaction). Potential expansion: suitable for petroleum chemical industry, environmental protection (such as wastewater catalysis) and pharmaceutical industry, etc., to solve the water sensitivity problem of traditional silica gel carrier.

[0094] Comparison with prior art: the specific surface area of traditional silica gel is <400m 2 / g, water resistance <80%, strength <8MPa, the present invention is superior in all aspects and fills the gap of water-resistant spherical silica gel.

[0095] The above is a further detailed description of the present invention in combination with specific embodiments, which cannot be considered as limiting the specific implementation of the present invention to these descriptions. For ordinary skilled persons in the technical field to which the present invention belongs, without departing from the concept of the present invention, a number of simple deductions or substitutions can be made, which should be considered as belonging to the protection scope determined by the claims submitted by the present invention.

Claims

1. A method for producing water-resistant spherical silica gel for catalyst carrier, characterized in that: The following steps are involved: (1) Preparation of nano seed sol: Sodium silicate aqueous solution or alkoxysilane is used as a silicon source, and at least one template selected from hexadecyltrimethylammonium chloride, polyethylene glycol or block copolymer F127 is mixed in a mass ratio of 100: (1-10), and nano silicon dioxide is added at the same time, and ultrasonic dispersion treatment is performed to obtain a uniform nano seed sol; (2) Preparation of gel microspheres: The nano seed sol obtained in step (1) is mixed with a non-polar organic solvent in a volume ratio of 1: (3-8) to obtain an oil-in-water emulsion, and then a promoter is added dropwise to the oil-in-water emulsion to form gel microspheres with an average particle size of 400 μm; (3) Preparation of silica gel skeleton: The gel microspheres obtained in step (2) are mixed with a pore expander in a volume ratio of 1: (3-8) to obtain an oil-in-water emulsion. The silica gel skeleton obtained in step (3) is mixed in a mass ratio of 1: (8-15), and then subjected to a hydrothermal reaction to obtain a spherical silica gel skeleton; (4) in situ modification reaction: the silica gel skeleton obtained in step (3) is subjected to an in situ modification reaction with a silicon-based modifier in a mass ratio of 10: (0.2-1.5) to obtain a preliminary product; (5) gradient hydrophilicity and hydrophobicity regulation: the preliminary product obtained in step (4) is activated with a hydrofluoric acid solution in a mass ratio of 1: (2-5), and then an ethanol solution containing a bifunctional coupling agent in an amount of 0.2-0.8 times the mass of the preliminary product is added for surface grafting to obtain microspheres with gradient hydrophilicity and hydrophobicity; (6) supercritical extraction: the microspheres obtained in step (5) are subjected to supercritical extraction, and finally subjected to a thermal activation treatment to obtain the final product.

2. The method for producing water-resistant spherical silica gel for catalyst support according to claim 1, characterized in that: The modulus of the sodium silicate aqueous solution in step (1) is 1.5-3.5, and its mass percentage is 5%-15%; the alkoxysilane in step (1) is tetraethyl orthosilicate, tetramethyl orthosilicate, methyltrimethoxysilane, methyltriethoxysilane, phenyltriethoxysilane, dodecyltriethoxysilane, 3-aminopropyltriethoxysilane or γ-glycidyloxypropyltrimethoxysilane.

3. The method for producing water-resistant spherical silica gel for catalyst support according to claim 1, characterized in that: The particle size of the nano-silicon dioxide in step (1) is 5-20 nm, and the amount thereof is 0.5-3.0% of the mass of the silicon source; the parameters of the ultrasonic dispersion treatment in step (1) are as follows: 5-20° C., 600-1000 W, 40-80 kHz, and 15-45 min.

4. The method for producing water-resistant spherical silica gel for catalyst support according to claim 2, characterized in that: The non-polar organic solvent in step (2) is cyclohexane or n-hexane; the mixing parameters in step (2) are as follows: a rotation speed of 8000-15000 rpm; the promoting liquid in step (2) is obtained by mixing triethylamine, acetic acid, zirconium n-propoxide and ethanol in a mass ratio of (0.8-2): (1-3): (2-6): (10-20); the dropping rate in step (2) is controlled to be 0.5-2.0 mL / min, and the pH value after the dropping is adjusted to be 4.0-6.

5.

5. The method for producing water-resistant spherical silica gel for catalyst support according to claim 1, characterized in that: In step (3), the pore expander is an alcohol-water mixed solution containing organic amines, wherein the alcohol-water mixed solution is a mixed solution of alcohol and water in a mass ratio of 1: (2-5), wherein the alcohol is ethanol, n-propanol, isopropanol, n-butanol, isobutanol, tert-butanol, n-pentanol, ethylene glycol, propylene glycol or cyclohexanol, wherein the organic amine is 0.2-0.4 times the mass of the alcohol-water mixed solution, wherein the organic amine is urea, methylamine or ethylenediamine.

6. The method for producing water-resistant spherical silica gel for catalyst support according to claim 1, characterized in that: The parameters of the hydrothermal reaction in step (3) are as follows: 120-220°C, 1.5-4 MPa and 12-18 h.

7. The method for producing water-resistant spherical silica gel for catalyst support according to claim 1, characterized in that: The silicon-based modifier in step (4) is trimethylchlorosilane, hexamethyldisilazane, vinyltriethoxysilane or 3-mercaptopropyltrimethoxysilane; the parameters of the in-situ modification reaction in step (4) are as follows: 50-80°C, 10-20 MPa and 4-8h.

8. The method for producing water-resistant spherical silica gel for catalyst support according to claim 1, characterized in that: The mass percentage of the hydrofluoric acid solution in step (5) is 0.5-2%; the parameters of the activation treatment in step (5) are as follows: 25-40° C. and 80-120 min; the bifunctional coupling agent in step (5) is 3-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane or vinyltriethoxysilane; the mass percentage of the bifunctional coupling agent in the ethanol solution in step (5) is 1-5%; the parameters of the surface grafting in step (5) are as follows: 60-80° C. and 8-12 h.

9. The method for producing water-resistant spherical silica gel for catalyst support according to claim 1, characterized in that: The parameters of supercritical extraction in step (6) are as follows: 35-60°C, 12-20 MPa and 6-10 h; the parameters of thermal activation treatment in step (6) are as follows: heating to 450-750°C at a heating rate of 5-15°C / min and calcining in nitrogen for 6-10.

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