A porous catalyst and a method for preparing a porous catalyst

Abstract

The application discloses a kind of porous catalyst and the preparation method of porous catalyst, including the purification treatment of styrene, obtain polystyrene nanosphere, it is as subsequent mesopore guiding hard template, introduce soft template P123, simultaneously introduce Mg2+ Functionalized micropore, and add Mg (NO3) 2·6H2O and tetramethoxysilane, obtain Mg2+ Homogeneous liquid containing, only then the mixing reaction of Mg2+ Homogeneous liquid with polystyrene nanosphere obtained previously, utilize polystyrene nanosphere formation macropore, and Sn2+ And In3+ Are introduced into macropore Functionalized macropore, form metal acid-base site by air calcination, to ensure that chemically not acid-base site is localized in space, the method disclosed in the application utilizes two different templates to form a large number of pores, and different catalytic sites are formed by functionalizing two kinds of pores respectively, forming a hierarchical pore catalyst containing acid-base sites simultaneously, the catalyst is used for catalytic conversion glucose to generate methyl lactate, and a yield of 58.81% can be achieved.

Description

Technical Field

[0001] This invention belongs to the field of catalyst preparation technology, and relates to a porous catalyst and a method for preparing a porous catalyst. Background Technology

[0002] Methyl lactate, also known as methyl 2-hydroxypropionate, has the molecular formula C4H8O3 and a molecular weight of 104.1. It is a colorless, transparent liquid, soluble in water and most organic solvents, and is an important hydroxy ester compound. Methyl lactate (MLA) is one of the most important platform compounds and has been widely used in the food, chemical, green solvent, and pharmaceutical industries. Various carbohydrates are used to synthesize methyl lactate in the presence of a catalyst. Among them, the C3 compound glycerol (GLY) and its derived trisaccharides (dihydroxyacetone (DHA) and glyceraldehyde (GLA)) have been used to produce alkyl lactates. However, compared to C3 compounds and their derived sugars, C6 monosaccharides (glucose, maltose, sucrose, galactose, and fructose), especially glucose as the most abundant and inexpensive hexose, are more ideal, as they can be obtained by hydrolyzing food residues rich in cellulose or starch. The preparation of lactate compounds using glucose as a raw material has gradually attracted attention. The conversion of glucose to methyl lactate is a complex process, primarily involving: 1) glucose isomerization to fructose; 2) the reverse aldol reaction of fructose to generate two C3 units (DHA and GA); and 3) the formation of methyl lactate through dehydration and subsequent 1,2-hydrogenation. Step 1) is typically catalyzed by a base or Lewis acid site, step 2) by a base site, and step 3) by a Lewis acid site, which accelerates the reaction and is weakly catalyzed. The presence of acid sites also accelerates the dehydration process. Therefore, the catalyst simultaneously contains a base, a Lewis acid, and... Acid sites are favorable for the reaction.

[0003] To date, a wide variety of catalytic systems, including homogeneous and heterogeneous systems, have been used to catalyze the production of methyl lactate from glucose in methanol. For example, homogeneous catalysts, including alkali metal salts and metal salts, as well as porous heterogeneous catalysts such as Sn-β, Sn-MWW, Sn-MCM-41, Sn-SBA-15, Zr-SBA-15 zeolite imidazole salt frameworks (ZIFs) ZIF-8 and ZIF-67, have been shown to efficiently generate methyl lactate. Compared to homogeneous catalysts, heterogeneous catalysts show more advantages in terms of ease of separation and recyclability. However, the incompatibility of acid-base sites makes it difficult for them to coexist on the same catalyst. Past studies have typically utilized "partitioning" or "positional isolation" to avoid direct contact between these sites and to integrate these chemically incompatible sites into a single material. For example, Yang et al. demonstrated a one-pot cascade reaction strategy based on picking up emulsion laminations and successfully separated incompatible or opposing sites to avoid their mutual destruction. However, this strategy suffers from poor physical and chemical stability of the materials and is often limited to specific applications, restricting its widespread use. Subsequently, Zhifang et al. synthesized a functional hypercrosslinked polymer (HCP) with a hollow spherical structure using a simple method to achieve harmonious coexistence of acid (sulfonic acid) and base (amine) sites. Kang et al. proposed a novel strategy called "iterative etch grafting," in which two incompatible sites—base (amine) and acid (sulfonic acid)—are progressively grafted onto SiO2 photonic beads. These efforts are encouraging examples of how incompatible cascade reactions can be made possible. However, all these catalysts utilize organic acids and bases with limited thermal stability, and the sulfonic acid groups are corrosive, which is not only detrimental to environmentally friendly development but also requires high thermal stability for the catalytic conversion of glucose to MLA. Therefore, when catalysts containing both acid and base sites are designed for the synthesis of MLA, their thermal stability and environmental friendliness are crucial. Summary of the Invention

[0004] The purpose of this invention is to solve the problems in the prior art and provide a porous catalyst and a method for preparing the porous catalyst.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] A method for preparing a porous catalyst includes the following steps:

[0007] S1: Obtain purified styrene. Mix the purified styrene with pure water and potassium persulfate aqueous solution, heat and stir. Polystyrene colloidal spheres are formed in the mixed solution. Then, centrifuge the mixed solution to obtain polystyrene nanospheres.

[0008] S2: P123 is added to hydrochloric acid aqueous solution and heated to form a homogeneous gel. Then, Mg(NO3)2·6H2O and tetramethoxysilane are added sequentially to obtain a homogeneous liquid containing Mg2+. Polystyrene nanospheres obtained in step S1 are added to the homogeneous liquid. The mixture formed by the homogeneous liquid and polystyrene nanospheres is then dried and aged to obtain S-Mg.

[0009] S3: Add cold toluene to S-Mg, stir and extract polystyrene nanospheres, and obtain the remaining solid after the polystyrene nanospheres are extracted. Dry the remaining solid to obtain S-Mg-D.

[0010] S4: Dissolve S-Mg-D in pure water, add SnCl2·2H2O and InCl3 to obtain a mixed solution, centrifuge the mixed solution, and recover the solid in the mixed solution after centrifugation to obtain S-Mg-D-In-Sn. Dry and calcine the S-Mg-D-In-Sn sequentially to obtain the porous acid-base catalyst S-Mg-In-Sn.

[0011] A further improvement of the present invention is that:

[0012] Step S1 also includes a process of purifying styrene:

[0013] Styrene was rinsed with NaOH solution and then washed with distilled water to remove inhibitors, yielding purified styrene.

[0014] In step S1, when the purified styrene is mixed with pure water and potassium persulfate aqueous solution and then heated and stirred, the temperature of the styrene is 70-80℃ and the stirring time is 20-24h.

[0015] In step S2, the ratio of P123 to hydrochloric acid aqueous solution is 1:1.

[0016] In step S2, the pH value of the hydrochloric acid aqueous solution is 1.9-2.2.

[0017] In step S2, when the mixture formed by mixing the homogeneous liquid and polystyrene nanospheres is dried and aged, the drying temperature is 40°C and the aging time is greater than or equal to 12 hours.

[0018] In step S3, the ratio of S-Mg to cold toluene is (3-10) g : (30-100) mL.

[0019] In step S3, the step of obtaining the remaining solid after the polystyrene nanospheres are extracted includes centrifuging and recovering the remaining solid after the polystyrene nanospheres are extracted using a refrigerated centrifuge at -10 to 0°C.

[0020] In step S4, when S-Mg-D-In-Sn is dried and calcined sequentially:

[0021] The drying temperature is 40-80℃;

[0022] The calcination time is 6-10 hours, and the calcination temperature is 400-500℃.

[0023] A variety of catalysts prepared using any one of the preparation methods of the present invention, wherein the catalysts are distributed with hierarchical pores containing acid and base sites.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] This invention discloses a method for preparing a porous catalyst. First, styrene is purified to obtain polystyrene nanospheres, which are then used as a hard template for subsequent macroporous pore guidance. A soft template, P123, is introduced, along with Mg2+ functionalized micropores. Mg(NO3)2·6H2O and tetramethoxysilane are added to obtain a homogeneous liquid containing Mg2+. This homogeneous liquid is then mixed with the previously obtained polystyrene nanospheres to form macropores. Sn2+ and In3+ are introduced into the macropores to functionalize them. Air calcination forms metal acid-base sites, ensuring the spatial localization of chemically incompatible acid-base sites. This method utilizes two different template agents to form a large number of pores, and by functionalizing the two types of pores, different catalytic sites are formed, resulting in a hierarchical porous catalyst containing both acid-base sites. When this catalyst is used to catalyze the conversion of glucose to methyl lactate, a yield of 58.81% can be achieved.

[0026] This invention discloses a porous catalyst, which is a hierarchical porous catalyst with a spatially orthogonal structure modified by metal oxides. The prepared catalyst has oxides of two metals, In and Sn, loaded on the catalyst surface to provide effective acid sites for the catalytic formation of methyl lactate. At the same time, the metal oxide sites of Mg are loaded on the catalyst surface to provide base sites for the catalytic formation of methyl lactate. Furthermore, the presence of its hierarchical pores and spatially orthogonal structure promotes the binding of the substrate to the catalytic sites and the diffusion of reaction products. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1This is a scanning electron microscope (SEM) image of SPO-1 of the present invention;

[0029] Figure 2 This is a nitrogen adsorption-desorption curve of SPO-1 of the present invention; Figure 3 The pressure curve of SPO-1 of the present invention.

[0030] Figure 4 shows the acid-base content analysis of SPO-1 (wherein, Figure 4a The NH3-TPD diagram of SPO-1 is shown. Figure 4b (CO2-TPD diagram of SPO-1);

[0031] Figure 5 This invention investigates the effects of reaction time and temperature on the SPO-1-catalyzed production of methyl lactate from glucose.

[0032] Figure 6 This is a diagram illustrating the reuse and application of the SPO-1 of the present invention. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0034] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0035] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0036] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0037] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0038] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0039] The present invention will now be described in further detail with reference to the accompanying drawings:

[0040] See Figure 1 This invention discloses a method for preparing a porous catalyst, comprising the following steps:

[0041] Step 1: Preparation of polystyrene nanospheres:

[0042] Take 100-110 mL of styrene and rinse it 4-6 times in a separatory funnel with 0.1 mol / L NaOH solution (the volume ratio of styrene to NaOH is 1:1). Then wash it with distilled water to remove the inhibitor (after this step, the colorless styrene will turn pale yellow and the sodium hydroxide will turn pink).

[0043] Furthermore, in this step, the washing is performed 4-6 times with distilled water;

[0044] Further, purified styrene was added to 800-900 mL of pure water at 70-80℃, and then 45-55 mL of 0.24 M potassium persulfate aqueous solution was added dropwise while stirring and heated and stirred for 20-24 h. Polystyrene colloidal spheres were formed, the solution turned white, and the solution was centrifuged to obtain highly ordered polystyrene nanospheres.

[0045] Grind into powder in a mortar and pass through an 80-100 mesh sieve. Collect the powder in a centrifuge tube and dry it. It will then be used as a hard template for guiding large pores.

[0046] Step 2: Prepare ordered, layered SBA-15 and introduce Mg2+:

[0047] 0.15-0.25 g of P123 was added to 0.15-0.25 g of hydrochloric acid aqueous solution, and a homogeneous gel was formed at 40 °C. Then, 0.3-0.6 g of Mg(NO3)2·6H2O was added. Next, the organic intermediate phase containing Mg2+ was treated with 4.0-4.5 mL of tetramethoxysilane to form a homogeneous liquid. Polystyrene nanospheres obtained in step 1 were added, and the mixture was dried overnight at 40 °C in a vacuum drying oven. Finally, it was aged at room temperature for more than 12 hours and ground through an 80-100 mesh sieve to obtain Mg-functionalized SBA-15 (i.e., S-Mg).

[0048] The pH value of the hydrochloric acid aqueous solution is 2.

[0049] Step 3: Polystyrene nanosphere template extraction to introduce macropores:

[0050] Take 3-10g of S-Mg, add 30-100mL of cold toluene, and stir evenly at (-10-0)℃ to extract the hard template (polystyrene nanospheres). Centrifuge at (-10-0)℃ using a high-speed refrigerated centrifuge to recover the solid after removing the hard template. Repeat the above process (3-5 times) to obtain the solid, which is then dried overnight in a vacuum oven at (40-80)℃. Grind the solid through an (80-100) mesh sieve to obtain a Mg-functionalized material with macropores (i.e., S-Mg-D).

[0051] Step 4: In-Sn conversion of S-Mg-D and formation of micropores:

[0052] Disperse S-Mg-D in 50-80 mL of pure water, add 0.06-0.12 g SnCl2·2H2O and 0.05-0.10 g InCl3 and stir for 6-12 h. Centrifuge the mixture and recover the solid, which is a material with macropores and the introduction of three metals (In, Sn and Mg) (i.e., S-Mg-D-In-Sn).

[0053] Furthermore, S-Mg-D-In-Sn was dried overnight at 40-80℃, and finally calcined in air at 400-500℃ in a muffle furnace for 6-10 hours to obtain a trimetallic modified (In, Sn and Mg) hierarchical pore (macropore, mesopore and micropore) catalytic material with a spatial orthogonal structure, named S-Mg-In-Sn.

[0054] Example 1

[0055] Step 1: Preparation of polystyrene colloidal clusters

[0056] Take 105 mL of styrene and rinse it 5 times with 0.1 mol / L NaOH solution in a separatory funnel (volume ratio 1:1). Then wash it 5 times with distilled water to remove the inhibitor. (After this step, the colorless styrene will turn pale yellow, and the sodium hydroxide will turn pink).

[0057] Next, purified styrene was added to 850 mL of pure water at 80 °C, and then 50 mL of 0.24 M potassium persulfate aqueous solution was added dropwise while stirring at 300 rpm and heated and stirred for 22 h. Polystyrene colloidal spheres formed, and the solution turned white. The solution was centrifuged at 9000 rpm for 20 minutes to obtain highly ordered polystyrene nanospheres, which were ground into powder in a mortar and passed through a 100-mesh sieve. The powder was collected in centrifuge tubes and dried, and will be used later as a rigid template for macroporous guidance.

[0058] Step 2: Preparation of ordered, layered SBA-15 (introduction of Mg2+)

[0059] 1.5 g of P123 was added to 1.5 g of hydrochloric acid aqueous solution with pH=2. The mixture formed a homogeneous gel at 40 °C. Then, 0.3 g of Mg(NO3)2·6H2O was added. Next, the organic intermediate phase containing Mg2+ was treated with 4.0 mL of tetramethoxysilane, and then the mixture was rapidly stirred at 800 rpm for 5 min to form a homogeneous liquid. Next, 6 g of polystyrene nanospheres were added, and the mixture was stirred at 100 rpm to ensure homogeneity. The mixture was dried in a vacuum drying oven at 40 °C and finally aged at room temperature for 24 h.

[0060] Step 3: Polystyrene nanosphere template extraction to introduce macropores

[0061] Take 3g of the substance obtained in step (2), add 30mL of cold toluene, stir at -10℃ to extract the hard template, and centrifuge at -10℃ using a high-speed refrigerated centrifuge to recover the solid. Repeat the above process 4 times, and dry the solid in a vacuum oven at 40℃. Grind it through a 100-mesh sieve to obtain a macroporous material.

[0062] Step 4: In-Snification of macropores and formation of micropores

[0063] Take 1g of the macroporous material obtained in step (3) and disperse it in 50mL of pure water. Add 0.06g of SnCl2·2H2O and 0.05g of InCl3, stir for 6h, centrifuge the recovered material and dry it overnight at 70℃. Finally, place it in a muffle furnace at 400℃ for 6h to obtain a porous catalyst containing both acid and base sites, named SPO.

[0064] Example 2

[0065] Step 1 of Example 2 is the same as step 1 of Example 1;

[0066] Step 2: Preparation of ordered, layered SBA-15 (introduction of Mg2+)

[0067] 2g of P123 was added to 2g of hydrochloric acid aqueous solution with pH=2. The mixture formed a homogeneous gel at 40℃. Then, 0.5g of Mg(NO3)2·6H2O was added. Next, the organic intermediate phase containing Mg2+ was treated with 4.08mL of tetramethoxysilane, and then rapidly stirred at 800 rpm for 5min to form a homogeneous liquid. Next, 6g of polystyrene nanospheres were added, and the mixture was stirred at 100 rpm to ensure homogeneity. The mixture was dried in a vacuum drying oven at 40℃ and finally aged at room temperature for 24h.

[0068] Step 3: Polystyrene nanosphere template extraction to introduce macropores

[0069] Take 10g of the substance obtained in step (2), add 100mL of cold toluene, stir at -8℃ to extract the hard template, and centrifuge at -8℃ using a high-speed refrigerated centrifuge to recover the solid. Repeat the above process 4 times, and dry the solid in a vacuum oven at 40℃. Grind the solid through a 100-mesh sieve to obtain a macroporous material.

[0070] Step 4: In-Snification of macropores and formation of micropores

[0071] Take 1g of the macroporous material obtained in step (3) and disperse it in 70mL of pure water. Add 0.06g of SnCl2·2H2O and 0.05g of InCl3, stir for 8h, centrifuge the recovered material and dry it overnight at 70℃. Finally, place it in a muffle furnace at 400℃ for 8h to obtain a porous catalyst containing both acid and base sites, named SPO-0.

[0072] Example 3

[0073] Similar to the first three steps of Example 2, step (4): Take 1g of the macroporous material obtained in step (3) and disperse it in 80mL of pure water. Add 0.12g of SnCl2·2H2O and 0.10g of InCl3, stir for 8h, centrifuge the recovered material and dry it overnight at 70℃. Finally, place it in a muffle furnace at 400℃ for 10h to obtain a porous catalyst containing both acid and base sites, named SPO-1.

[0074] See Figure 1 SEM analysis revealed the surface morphology of the catalyst, showing that pores are uniformly distributed on the catalyst surface.

[0075] See Figure 2 As shown in Figure 4, the pores uniformly distributed on the catalyst surface are mainly micropores, but also contain macropores.

[0076] Table 1 lists the structural data of the catalyst, including BET surface area, pore volume, and pore size. As shown in Table 1, the catalyst has a high BET specific surface area of ​​819.56 m2 / g, of which micropores contribute 375.63 m2 / g and other micropores contribute 443.92 m2 / g. This value is significantly higher than most previously reported inorganic porous catalysts, with pore volume and pore size of 0.023 m3 / g and 2.10 nm, respectively.

[0077]

[0078]

[0079] See Figure 4a It can be seen that the catalyst exhibits two distinct peaks near 120℃ and 600℃, corresponding to weak and strong acid sites, respectively. (See also...) Figure 4b It can be seen that the CO2 desorption peaks on the catalyst appear in the ranges of 100-450℃ and 550-650℃, representing weak and strong basicity, respectively.

[0080] Table 2 lists the acid and base contents in the catalyst, with total amounts of 0.732 and 0.656 mmol / g, respectively. The contents of strong acid and strong base in the catalyst are 0.458 and 0.507 mmol / g, respectively, accounting for 62.52% and 77.30% of the total acid and base content. Overall, the prepared catalyst successfully combines two incompatible acid-base sites on the same material.

[0081]

[0082] See Figure 5 It can be seen that the MLA yield also increases with increasing temperature from 140℃ to 170℃, reaching a peak MLA yield of 58.81% after 22 hours at 160℃. When the temperature is further increased to 170℃, the MLA yield decreases slightly. The possible reason for the decrease in MLA yield with increasing temperature is the formation of other byproducts or downstream products (such as humin). This is because the process of producing MLA from glucose requires Lewis acid and... The process can only proceed under the influence of acid sites, and SnCl2·2H2O and InCl2 are catalysts used in the preparation of Lewis acids and... The acidic sites of the feedstock, therefore, SPO-1 catalyzed the methanolysis of glucose to produce MLA with excellent results. Furthermore, within each reaction temperature, the yield of MLA initially increases gradually with increasing reaction time, then gradually decreases after reaching a peak due to the polymerization process occurring over a longer reaction time.

[0083] See Figure 6The stability and reusability of SPO-1-catalyzed production of methyl lactate from glucose were investigated at the optimal reaction temperature and time described in the previous study. After the reaction, the solid and liquid phases were separated, and the solid was washed three times with methanol and dried overnight at 70°C in an oven. It was then used directly in the next reaction without regeneration. Due to losses during the recovery process and the accumulation of deposits, the yield of methyl lactate decreased from 58.81% in the first round to 49.71% after four cycles. Therefore, after the fourth round of reaction, the recovered catalyst was calcined at 400°C for regeneration and used again in the fifth round of reaction, achieving a methyl lactate yield of 52.65%, an improvement compared to the fourth round. In summary, SPO-1 remains stable and reusable when used for the conversion of glucose to methyl lactate.

[0084] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a porous catalyst, characterized in that, Includes the following steps: S1: Styrene was rinsed with NaOH solution and then washed with distilled water to remove inhibitors, resulting in purified styrene. The purified styrene was then mixed with pure water and potassium persulfate solution and heated and stirred. Polystyrene colloidal spheres were formed in the mixed solution. The mixed solution was then centrifuged to obtain polystyrene nanospheres. S2: P123 was added to an aqueous hydrochloric acid solution and heated to form a homogeneous gel. Then, Mg(NO3)2·6H2O and tetramethoxysilane were added sequentially to obtain a product containing Mg. 2+ A homogeneous liquid was prepared by adding polystyrene nanospheres obtained in step S1 to the homogeneous liquid, and then drying and aging the mixture formed by mixing the homogeneous liquid and polystyrene nanospheres to obtain S-Mg. S3: Add cold toluene to S-Mg, stir and extract polystyrene nanospheres, and obtain the remaining solid after the polystyrene nanospheres are extracted. Dry the remaining solid to obtain S-Mg-D. S4: S-Mg-D is dispersed in pure water, SnCl2·2H2O and InCl3 are added to obtain a mixed solution. The mixed solution is centrifuged and the solid in the mixed solution after centrifugation is recovered to obtain S-Mg-D-In-Sn. S-Mg-D-In-Sn is dried and calcined in sequence to obtain the porous acid-base catalyst S-Mg-In-Sn.

2. The method for preparing a porous catalyst according to claim 1, characterized in that, In step S1, when the purified styrene is mixed with pure water and potassium persulfate aqueous solution and then heated and stirred, the temperature of the styrene is 70-80℃ and the stirring time is 20-24h.

3. The method for preparing a porous catalyst according to claim 1, characterized in that, In step S2, the mass ratio of P123 to hydrochloric acid aqueous solution is 1:

1.

4. The method for preparing a porous catalyst according to claim 2, characterized in that, In step S2, the pH value of the hydrochloric acid aqueous solution is 1.9-2.

2.

5. The method for preparing a porous catalyst according to claim 3, characterized in that, In step S2, when the mixture formed by mixing the homogeneous liquid and polystyrene nanospheres is dried and aged, the drying temperature is 40 °C and the aging time is greater than or equal to 12 hours.

6. The method for preparing a porous catalyst according to claim 1, characterized in that, In step S3, the ratio of S-Mg to cold toluene is (3-10) g : (30-100) mL.

7. The method for preparing a porous catalyst according to claim 6, characterized in that, In step S3, the step of obtaining the remaining solid after the polystyrene nanospheres are extracted includes centrifuging and recovering the remaining solid after the polystyrene nanospheres are extracted using a refrigerated centrifuge at -10 to 0 °C.

8. The method for preparing a porous catalyst according to claim 1, characterized in that, In step S4, when S-Mg-D-In-Sn is dried and calcined sequentially: The drying temperature is 40-80℃; The calcination time is 6-10 hours, and the calcination temperature is 400-500℃.

9. A porous catalyst prepared by the preparation method according to any one of claims 1 to 8, characterized in that, The catalyst has hierarchical pores containing acid and base sites.

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