Karstedt catalyst and preparation method thereof

Abstract

The invention discloses a Karstedt catalyst and a preparation method thereof, and belongs to the technical field of catalysts. The preparation method provided by the invention comprises the following steps: firstly, chloroplatinic acid reacts with three different siloxanes to generate a zero-valent platinum complex, the siloxanes are tetradimethyl vinyl siloxy silane, tetramethyl divinyl disiloxane and 1, 3-dimethyl-1, 1, 3, 3-tetraethylene disiloxane, calcium oxide is added in the reaction to be matched with sodium bicarbonate to neutralize, and then the zero-valent platinum complex is obtained. And after the reaction, reducing residual bivalent platinum by using sodium borohydride, and finally loading by using an SBA15 molecular sieve as a carrier to obtain the finished product Karstedt catalyst. The multi-ligand Karstedt catalyst is formed by combining a tetradentate ligand, a conventional chain ligand and a branched chain polyvinyl ligand, the multi-ligand Karstedt catalyst has high catalytic activity and stability, the loading capacity and the loading binding force are improved through a network architecture of a complex configuration, the dosage of the supported catalyst is reduced, and the cyclic utilization rate is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of catalysts, and particularly relates to a Karstedt catalyst and a preparation method thereof. Background Art

[0002] The hydrosilylation reaction occupies an important position in the field of organosilicon chemistry, but the reaction conditions of the hydrosilylation reaction are harsh and require specific catalysts to improve selectivity. The catalysts currently used are mostly transition metal complex catalysts, among which platinum complex catalysts show better catalytic effects.

[0003] The presence of inorganic chlorine in platinum complex catalysts does not promote the reaction, but reduces the activity of the catalyst. Karstedt catalyst is a homogeneous catalyst that contains almost no inorganic chlorine and has high catalytic activity. Its main catalytic active component is Pt 2+ and Pt 0 The traditional Karstedt catalyst is to dissolve chloroplatinic acid in ethanol, add sodium bicarbonate and tetramethyldivinyldisiloxane, and then heat the reaction to form a platinum-siloxane complex. The fundamental reason is that platinum is reduced to zero valent in the reaction, and tetramethyldivinyldisiloxane coordinates with the zero valent platinum through the vinyl group.

[0004] There are certain defects in the existing Karstedt catalyst. The first is poor stability. The Karstedt catalyst is a complex formed by zero-valent platinum and a ligand. From the perspective of coordination chemistry, the state of this complex is unstable, and other elements (Cl, S), temperature, and oxygen all affect the stability of the catalyst. In order to solve this problem, the prior art enhances coordination ability by selecting different ligands. For example, a terminal triene compound is used as a ligand. The triene group in the structure can form a stable coordination bond with platinum, and the stability of the complex formed is higher, but the catalytic activity of this complex can be reduced under the same platinum content. The second is the problem that the catalyst cannot be recycled. The raw material cost of the Karstedt catalyst is higher, and cost pressure can be increased when it cannot be recycled. In order to solve this problem, the Karstedt catalyst is usually loaded with a carrier. The general carrier is activated carbon, Al2O3, and porous materials such as SiO2. However, there is a problem that the catalyst dosage is large in the existing supported Karstedt catalyst, causing the supported catalyst to be still in the laboratory research stage. Summary of the Invention

[0005] The present invention provides a Karstedt catalyst and a preparation method thereof, which can solve the problems in the prior art that the new Karstedt catalyst has poor stability and requires a large amount of catalyst after loading.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A method for preparing a Karstedt catalyst comprises the following steps:

[0008] Step 1: Under nitrogen protection, solvent, tetradimethylvinylsiloxysilane, tetramethyldivinyldisiloxane, 1,3-dimethyl-1,1,3,3-tetravinyldisiloxane, sodium bicarbonate and chloroplatinic acid are added to a flask in sequence, reacted at 60-80°C for 1-2 hours, calcium oxide particles are added, the reaction is continued for 1-2 hours, and cooled and filtered;

[0009] Step 2: add an ethanol solution of sodium borohydride to the filtrate, stir at room temperature for 1-2 hours, and distill under reduced pressure to obtain a crude product, which is then washed with water and distilled to obtain a purified product;

[0010] Step 3: The purified product was dissolved in benzene, SBA15 molecular sieves were added, stirred and refluxed for 6-10 hours, and then distilled under reduced pressure and dried to obtain a Karstedt catalyst.

[0011] Furthermore, the solvent is one of anhydrous ethanol and isopropyl alcohol.

[0012] Furthermore, the molar ratio of tetradimethylvinylsiloxysilane, tetramethyldivinyldisiloxane, 1,3-dimethyl-1,1,3,3-tetravinyldisiloxane and chloroplatinic acid is (0.8-1.6): (1.4-2): (0.2-0.8): 0.1.

[0013] Tetramethylvinylsiloxysilane is a tetradentate ligand, tetramethyldivinyldisiloxane is a conventional chain ligand, and 1,3-dimethyl-1,1,3,3-tetravinyldisiloxane is a branched polyvinyl ligand. When all three ligands participate in the reaction, from a single structure, tetramethylvinylsiloxysilane and 1,3-dimethyl-1,1,3,3-tetravinyldisiloxane can form multiple coordinations with zero-valent platinum, exposing more active sites and enhancing catalytic activity. Furthermore, the tetrahedral Si centers of tetramethylvinylsiloxysilane induce σ-π conjugation, raising the π orbital energy level of the coordinating vinyl groups and promoting feedback bond formation for Pt coordination, resulting in a more stable complex. The branched structure of 1,3-dimethyl-1,1,3,3-tetravinyldisiloxane results in a non-coplanar angle between the two vinyl groups, forming an asymmetric coordination field. This induces a localized region of high electron density at the Pt center, strengthening the coordination interaction and enhancing the stability of the complex.

[0014] From the perspective of multi-ligand binding, on the one hand, the complex of tetrakis(dimethylvinylsiloxysilane) and zero-valent platinum forms a tightly structured spatial skeleton, the complex of tetrakis(dimethylvinyldisiloxane) and zero-valent platinum has a chain structure, and the complex of 1,3-dimethyl-1,1,3,3-tetrakis(dimethyldisiloxane) and zero-valent platinum has a branched structure. When loaded, the larger skeleton structure of the complex of tetrakis(dimethylvinylsiloxysilane) and zero-valent platinum can be better spatially confined and fixed in the mesopores of the carrier, and the complex of tetrakis(dimethylvinyldisiloxane) and zero-valent platinum can serve as a "bridge" of the skeleton structure to form a continuous complex. The branched vinyl groups of the complex of 1,3-dimethyl-1,1,3,3-tetravinyldisiloxane and zero-valent platinum can form multi-anchor adsorption, supplement the network gaps of the loaded complex, realize a tight and continuous complex structure after loading, increase the loading amount, and enhance the catalytic activity; on the other hand, the interaction between the complex of single tetramethyldivinyldisiloxane and zero-valent platinum and the carrier only forms weak hydrogen bonds through the surface silanol groups, and the recycling rate after loading is low. When the three ligands are combined, the mutual restraint of the physical structure and the synergistic effect of hydrogen bonding are used to significantly enhance the loading binding force and increase the recycling rate.

[0015] Furthermore, the molar ratio of the sodium bicarbonate to the chloroplatinic acid is 8-12:1.

[0016] Furthermore, the molar ratio of the calcium oxide particles to sodium bicarbonate is 0.2-0.4:1, and the particle size of the calcium oxide particles is 2-3 mm.

[0017] Calcium oxide is used as a supplementary neutralizing agent in the preparation. Different from the conditions of using only sodium bicarbonate, the addition of calcium oxide to the reaction can, on the one hand, assist in neutralizing the HCl produced by the reaction. On the other hand, calcium oxide can act as a desiccant to absorb the water produced by the neutralization of HCl by sodium bicarbonate in the early stage, thereby avoiding the increase of moisture in the later stage and the hydrolysis of siloxane to produce small molecular substances, thereby reducing side reactions.

[0018] Furthermore, the mass ratio of the solvent to the siloxane is 5-10:1.

[0019] Furthermore, the concentration of the sodium borohydride ethanol solution is 0.1-0.3 mol / L.

[0020] Furthermore, the molar ratio of sodium borohydride to chloroplatinic acid is 0.4-0.8:1.

[0021] The reaction mechanism of chloroplatinic acid and siloxane is that Pt in chloroplatinic acid 4+ Reduced to Pt 0 , and then formed a complex with vinyl. When acting on the hydrogenation addition reaction, the catalytic activity of zero-valent platinum was significantly stronger than that of Pt 4+ and Pt 2+But in the actual catalyst preparation process, the reduction of platinum is affected by many factors, including temperature, time, siloxane amount and sodium bicarbonate amount, etc., but in the reaction, complete reduction of platinum cannot be achieved by controlling these reaction conditions only, and the existence of divalent platinum is still unavoidable. After the reaction, the addition of sodium borohydride ethanol solution can reduce divalent platinum to zero valence platinum by using the reducing property of sodium borohydride, and at room temperature, the decomposition of the complex formed can be avoided, so that after the reduction of divalent platinum to zero valence platinum, in-situ complexation is ensured, the content of divalent platinum is reduced, the content of zero valence platinum is increased, and the catalytic activity is improved.

[0022] Further, the mass ratio of the SBA15 molecular sieve to the purified product is 10-20:1.

[0023] The application also provides a Karstedt catalyst prepared by the preparation method of the Karstedt catalyst.

[0024] The application has the following beneficial effects:

[0025] (1) The application combines a tetradentate ligand (tetramethylethylene siloxysilane), a conventional chain ligand (tetramethyldivinyl disiloxane) and a branched polyvinyl ligand (1,3-dimethyl-1,1,3,3-tetraethylenedisiloxane) to form a multi-ligand synergistic Karstedt catalyst, which improves the catalytic activity and stability by using the multi-coordination configuration between the ligand and zero-valent platinum, reduces the sensitivity of the Karstedt catalyst to oxygen and moisture, and solves the problem of difficult storage of the Karstedt catalyst.

[0026] (2) The application uses SBA15 molecular sieve as a catalyst carrier, and the flexible ligand network architecture can effectively improve the loading amount of the active component and the silicon loading binding force, and construct the Karstedt catalyst with the integrated hard porous inorganic silicon structure and flexible organic silicon chain. Compared with the traditional Karstedt catalyst, the application can not only solve the significant disadvantage that the Karstedt catalyst is difficult to recycle after use, improve the recycling rate, but also reduce the use loss of the Karstedt catalyst, and greatly reduce the loss of the precious metal platinum.

[0027] (3) In the preparation process, calcium oxide particles are used as a neutralizing agent and a water reducing agent to further enhance the neutralization effect on acidic substances, and the large particles are easy to separate, and the reaction with water can generate calcium hydroxide, thereby reducing the influence of moisture on the organic reaction. This not only can improve the reaction efficiency and reduce the generation of by-products, but also the reduction of moisture can promote the inorganic substances to remain in the reaction system in the form of solids, greatly reducing the residue of the reactants. In addition, the alkaline environment is also conducive to enhancing the reduction effect of sodium borohydride, increasing the generation amount of elemental platinum catalyst, improving the atom economy, and making it more characteristic of green chemical reaction. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0029] Embodiment 1

[0030] A preparation method of Karstedt catalyst, comprising the following steps:

[0031] Step one, under nitrogen protection, anhydrous ethanol, tetra-dimethylvinylsiloxy silane, tetramethyl divinyl disiloxane, 1,3-dimethyl-1,1,3,3-tetravinyl disiloxane, sodium bicarbonate and chloroplatinic acid are sequentially added into a flask, and reacted at 70℃ for 1.5h, calcium oxide particles (particle size of 2-3mm) are added, and the reaction is continued for 1.5h, and then filtered after cooling. The molar ratio of tetra-dimethylvinylsiloxy silane, tetramethyl divinyl disiloxane, 1,3-dimethyl-1,1,3,3-tetravinyl disiloxane and chloroplatinic acid is 1:2:0.5:0.1, the molar ratio of sodium bicarbonate and chloroplatinic acid is 10:1, the molar ratio of calcium oxide and sodium bicarbonate is 0.3:1, and the mass ratio of anhydrous ethanol and siloxane (tetra-dimethylvinylsiloxy silane, tetramethyl divinyl disiloxane and 1,3-dimethyl-1,1,3,3-tetravinyl disiloxane) is 10:1.

[0032] Step two, sodium borohydride ethanol solution with a concentration of 0.2mol / L is added to the filtrate, the molar ratio of sodium borohydride and chloroplatinic acid is 0.4:1, stirred at room temperature for 2h, and then the crude product is obtained by reduced pressure distillation, the crude product is dissolved in 10 times the mass of benzene, the by-product is removed by adding deionized water with the same volume of benzene, and then the solvent is removed by distillation to obtain the purified product;

[0033] Step three, the purified product is dissolved in benzene, the mass concentration of the purified product is 10g / L, SBA15 molecular sieve is added, the mass ratio of SBA15 molecular sieve and the purified product is 20:1, stirred and refluxed for 10h, dried after reduced pressure distillation, and then Karstedt catalyst is obtained.

[0034] Embodiment 2

[0035] The difference from embodiment 1 is that the molar ratio of tetra-dimethylvinylsiloxy silane, tetramethyl divinyl disiloxane, 1,3-dimethyl-1,1,3,3-tetravinyl disiloxane and chloroplatinic acid is 1.2:1.8:0.4:0.1.

[0036] Example 3

[0037] The only difference from Example 1 is that the molar ratio of tetradimethylvinylsiloxysilane, tetramethyldivinyldisiloxane, 1,3-dimethyl-1,1,3,3-tetravinyldisiloxane and chloroplatinic acid is 1.6:1.4:0.2:0.1.

[0038] Example 4

[0039] The only difference from Example 2 is that the molar ratio of tetrakis(dimethylvinylsiloxysilane), tetramethyldivinyldisiloxane, 1,3-dimethyl-1,1,3,3-tetravinyldisiloxane and chloroplatinic acid is 1.0:1.8:0.6:0.1.

[0040] Example 5

[0041] The only difference from Example 2 is that the molar ratio of tetrakis(dimethylvinylsiloxysilane), tetrakis(dimethylvinyldisiloxane), 1,3-dimethyl-1,1,3,3-tetravinyldisiloxane and chloroplatinic acid is 0.8:1.8:0.8:0.1.

[0042] Example 6

[0043] The only difference from Example 4 is that the molar ratio of sodium borohydride to chloroplatinic acid is 0.6:1.

[0044] Example 7

[0045] The only difference from Example 4 is that the molar ratio of sodium borohydride to chloroplatinic acid is 0.8:1.

[0046] Comparative Example 1

[0047] The only difference from Example 1 is that the molar ratio of tetradimethylvinylsiloxysilane, tetramethyldivinyldisiloxane, 1,3-dimethyl-1,1,3,3-tetravinyldisiloxane and chloroplatinic acid in the preparation of the Karstedt catalyst is 0.6:2.2:0.8:0.1.

[0048] Comparative Example 2

[0049] The only difference from Example 1 is that the molar ratio of tetradimethylvinylsiloxysilane, tetramethyldivinyldisiloxane, 1,3-dimethyl-1,1,3,3-tetravinyldisiloxane and chloroplatinic acid in the preparation of the Karstedt catalyst is 1.7:1.2:0.4:0.1.

[0050] Comparative Example 3

[0051] The difference from Example 1 is only that the molar ratio of tetra-dimethylvinylsiloxy silane, tetramethyl divinyl disiloxane, 1,3-dimethyl-1,1,3,3-tetravinyl disiloxane and chloroplatinic acid in the preparation of Karstedt catalyst is 1.0:1.0:1.0:0.1.

[0052] Comparative Example 4

[0053] The difference from Example 1 is only that no calcium oxide particles are added as a supplementary neutralizing agent in the preparation of Karstedt catalyst.

[0054] A preparation method of Karstedt catalyst, comprising the following steps:

[0055] Step one, under nitrogen protection, anhydrous ethanol, tetra-dimethylvinylsiloxy silane, tetramethyl divinyl disiloxane, 1,3-dimethyl-1,1,3,3-tetravinyl disiloxane, sodium bicarbonate and chloroplatinic acid are sequentially added to a flask, and reacted at 70°C for 3h, and then cooled and filtered. The molar ratio of tetra-dimethylvinylsiloxy silane, tetramethyl divinyl disiloxane, 1,3-dimethyl-1,1,3,3-tetravinyl disiloxane and chloroplatinic acid is 1:2:0.5:0.1, the molar ratio of sodium bicarbonate and chloroplatinic acid is 10:1, and the mass ratio of anhydrous ethanol and siloxane (tetra-dimethylvinylsiloxy silane, tetramethyl divinyl disiloxane and 1,3-dimethyl-1,1,3,3-tetravinyl disiloxane) is 10:1.

[0056] Step two, sodium borohydride ethanol solution with a concentration of 0.2mol / L is added to the filtrate, the molar ratio of sodium borohydride and chloroplatinic acid is 0.4:1, stirred at room temperature for 2h, and then the crude product is obtained by reduced pressure distillation, the crude product is dissolved in 10 times the mass of benzene, the by-product is removed by adding deionized water with the same volume of benzene, and the purified product is obtained by distillation to remove the solvent;

[0057] Step three, the purified product is dissolved in benzene, the mass concentration of the purified product is 10g / L, SBA15 molecular sieve is added, the mass ratio of SBA15 molecular sieve and the purified product is 20:1, stirred and refluxed for 10h, dried after reduced pressure distillation, and then the Karstedt catalyst is obtained.

[0058] Comparative Example 5

[0059] The difference from Example 1 is only that calcium oxide particles replace sodium bicarbonate as a neutralizing agent in the preparation of Karstedt catalyst, and one-step addition is not supplemented.

[0060] A preparation method of Karstedt catalyst, comprising the following steps:

[0061] Step one, under nitrogen protection, anhydrous ethanol, tetra-dimethylvinylsiloxy silane, tetramethyl divinyl disiloxane, 1,3-dimethyl-1,1,3,3-tetravinyl disiloxane, calcium oxide particles (particle size 2-3mm) and chloroplatinic acid were sequentially added to a flask, reacted at 70℃ for 3h, cooled and filtered. Among them, the molar ratio of tetra-dimethylvinylsiloxy silane, tetramethyl divinyl disiloxane, 1,3-dimethyl-1,1,3,3-tetravinyl disiloxane and chloroplatinic acid is 1:2:0.5:0.1, the molar ratio of calcium oxide and chloroplatinic acid is 10:1, and the mass ratio of anhydrous ethanol and siloxane (tetra-dimethylvinylsiloxy silane, tetramethyl divinyl disiloxane and 1,3-dimethyl-1,1,3,3-tetravinyl disiloxane) is 10:1.

[0062] Step two, sodium borohydride ethanol solution with a concentration of 0.2mol / L was added to the filtrate, the molar ratio of sodium borohydride to chloroplatinic acid was 0.4:1, stirred at room temperature for 2h, and the crude product was obtained by reduced pressure distillation, the crude product was dissolved in 10 times the mass of benzene, and the by-product was removed by adding deionized water with the same volume of benzene and distilling off the solvent to obtain the purified product;

[0063] Step three, the purified product was dissolved in benzene, the mass concentration of the purified product was 10g / L, SBA15 molecular sieve was added, the mass ratio of SBA15 molecular sieve to the purified product was 20:1, stirred and refluxed for 10h, dried after reduced pressure distillation to obtain Karstedt catalyst.

[0064] Comparative example 6

[0065] The difference from example 1 is only that no sodium borohydride ethanol solution is added for reduction in the preparation of Karstedt catalyst.

[0066] A preparation method of Karstedt catalyst, comprising the following steps:

[0067] Step one, under nitrogen protection, anhydrous ethanol, tetra-dimethylvinylsiloxy silane, tetramethyl divinyl disiloxane, 1,3-dimethyl-1,1,3,3-tetravinyl disiloxane, sodium bicarbonate and chloroplatinic acid were sequentially added to a flask, reacted at 70℃ for 1.5h, calcium oxide particles (particle size 2-3mm) were added, and the reaction was continued for 1.5h, then cooled and filtered. Among them, the molar ratio of tetra-dimethylvinylsiloxy silane, tetramethyl divinyl disiloxane, 1,3-dimethyl-1,1,3,3-tetravinyl disiloxane and chloroplatinic acid is 1:2:0.5:0.1, the molar ratio of sodium bicarbonate and chloroplatinic acid is 10:1, the molar ratio of calcium oxide and sodium bicarbonate is 0.3:1, and the mass ratio of anhydrous ethanol and siloxane (tetra-dimethylvinylsiloxy silane, tetramethyl divinyl disiloxane and 1,3-dimethyl-1,1,3,3-tetravinyl disiloxane) is 10:1.

[0068] Step two, the filtrate is distilled under reduced pressure to obtain a crude product, the crude product is dissolved in 10 times the mass of benzene, and the by-products are removed by washing with benzene and deionized water in equal volume. The solvent is removed by distillation to obtain the purified product;

[0069] Step three, the purified product is dissolved in benzene, the mass concentration of the purified product is 10 g / L, SBA15 molecular sieve is added, the mass ratio of SBA15 molecular sieve to the purified product is 20:1, stirring is refluxed for 10 h, and then dried after distillation under reduced pressure to obtain the Karstedt catalyst.

[0070] The catalysts prepared by Examples 1-7 and Comparative Examples 1-6 are tested for catalytic performance, and the results are shown in Table 1. The specific catalytic performance test is as follows:

[0071] 1-octadecene and trimethoxysilane are taken for a silicon-hydrogen addition reaction. The 1-octadecene and trimethoxysilane are placed in a flask according to a molar ratio of 1:1, and a catalyst with a mass fraction of 5% trimethoxysilane is added. The reaction is carried out under nitrogen protection at 80°C for 6 h. After the reaction is completed, the product is filtered to obtain the product, and the conversion rate of 1-octadecene is detected.

[0072] Cyclic performance: the product after filtration and drying after the reaction is directly recycled and used repeatedly for 5 times, and the conversion rate of 1-octadecene is detected.

[0073] Table 1

[0074]

[0075]

[0076] As can be seen from Table 1, in the three-ligand catalyst system of the present application, the molar ratio adjustment of the three different ligands will affect the stability and catalytic activity of the complex. In Examples 1-5, the catalyst prepared at the ratio of Example 4 has the highest catalytic activity and the best stability, and the conversion rate is as high as 73.6% after repeated use for 5 times. In Examples 6 and 7, the amount of sodium borohydride has a certain influence on the catalytic activity. Appropriate addition is conducive to the reduction of platinum and improves the catalytic activity, but excessive sodium borohydride may produce side reactions and is not conducive to the reaction. In combination with Examples 1, Comparative Examples 1, 2 and 3, excessive or insufficient addition of any of the three ligands will weaken the synergistic effect of the overall complex system, and the conversion rate will decrease. In combination with Examples 1, Comparative Examples 4 and 5, it can be seen that the use of calcium oxide alone as a neutralizing agent or sodium bicarbonate alone as a neutralizing agent is not as good as the combined use of calcium oxide and sodium bicarbonate.

[0077] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting; it is not intended to exclude myriad other embodiments of the present application that other inventors can develop based on the same general inventive concepts embodied by the described embodiments. That is, although the present application is described in terms of particular embodiments and illustrative figures, it should be apparent that the scope of the present application is not limited to these specific embodiments.

[0078] While the embodiments of the application have been shown and described herein, it will be understood by those skilled in the art that many changes, modifications, substitutions and alterations to these embodiments can be made without departing from the principles and spirits of the application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a Karstedt catalyst, characterized in that: The following steps are involved: Step 1: Under nitrogen protection, solvent, tetradimethylvinylsiloxysilane, tetramethyldivinyldisiloxane, 1,3-dimethyl-1,1,3,3-tetravinyldisiloxane, sodium bicarbonate and chloroplatinic acid are added to a flask in sequence, reacted at 60-80°C for 1-2 hours, calcium oxide particles are added and the reaction is continued for 1-2 hours, and cooled and filtered; Step 2: Add sodium borohydride ethanol solution to the filtrate and stir at room temperature for 1-2 hours, and distill under reduced pressure to obtain a crude product, which is then washed with water and distilled to obtain a purified product; Step 3: The purified product was dissolved in benzene, SBA15 molecular sieves were added, stirred and refluxed for 6-10 hours, and then distilled under reduced pressure and dried to obtain the Karstedt catalyst.

2. The method for preparing a Karstedt catalyst according to claim 1, wherein: The solvent is one of anhydrous ethanol and isopropyl alcohol.

3. The method for preparing a Karstedt catalyst according to claim 1, characterized in that: The molar ratio of tetradimethylvinylsiloxysilane, tetramethyldivinyldisiloxane, 1,3-dimethyl-1,1,3,3-tetravinyldisiloxane and chloroplatinic acid is 1:(1-2):(0.5-1):0.

1.

4. The method for preparing a Karstedt catalyst according to claim 1, wherein: The molar ratio of the sodium bicarbonate to the chloroplatinic acid is 8-12:

1.

5. The method for preparing a Karstedt catalyst according to claim 1, characterized in that: The molar ratio of the calcium oxide particles to sodium bicarbonate is 0.2-0.4:1, and the particle size of the calcium oxide particles is 2-3 mm.

6. The method for preparing a Karstedt catalyst according to claim 1, characterized in that: The mass ratio of the solvent to the siloxane is 5-10:

1.

7. The method for preparing a Karstedt catalyst according to claim 1, characterized in that: The concentration of the sodium borohydride ethanol solution is 0.1-0.3 mol / L.

8. The method for preparing a Karstedt catalyst according to claim 1, characterized in that: The molar ratio of the sodium borohydride to the chloroplatinic acid is 0.4-0.8:

1.

9. The method for preparing a Karstedt catalyst according to claim 1, characterized in that: The mass ratio of the SBA15 molecular sieve to the purified product is 10-20:

1.

10. A Karstedt catalyst, characterized in that The catalyst is prepared by the preparation method of the Karstedt catalyst according to any one of claims 1 to 9.

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