Double metal cyanide catalyst and preparation method thereof

Abstract

The present invention relates to the field of catalyst preparation, in particular to a double metal cyanide catalyst and a preparation method thereof. Comprise the following steps: step one: potassium cobalt cyanide is dissolved in deionized water, ultrasonically stirred for 10 15min to obtain solution A; step two: ferrous sulfate heptahydrate, a complexing agent, and deionized water are mixed, and placed in a 25 DEG C constant temperature water bath and vigorously stirred to obtain solution B; step three: solution A is added dropwise to solution B, stirred for 3 4h, aged for 48 50h, and post-processed to obtain a double metal cyanide catalyst. Beneficial effect: the present invention is modified by 3 mercaptopropyltrimethoxysilane, and acts as a complexing agent together with a straight-chain alcohol, thereby increasing the specific surface area of ​​the catalyst, increasing the number of active sites of the catalyst as a whole, and then effectively activating the reactant molecules to promote the reaction.

Description

Technical Field

[0001] The present invention relates to the field of catalyst preparation, in particular to a double metal cyanide catalyst and a preparation method thereof. Background Art

[0002] Double metal cyanide (DMC) catalysts are a class of compounds with unique structures and catalytic properties. They consist of two different metal ions and a cyanide ligand. Due to their unique electronic properties and tunable structural characteristics, these catalysts have shown broad application potential in various chemical fields, especially in promoting environmentally friendly chemical reactions.

[0003] DMCs were first discovered in the 1970s and were primarily used in industrial polymer production, such as the synthesis of polyesters and polyethers. Over time, scientists discovered that DMCs have remarkable activity and selectivity in catalyzing CO2 conversion and ring-opening polymerization of epoxides. These reactions are crucial for the synthesis of biodegradable polycarbonates, which have a wide range of applications in packaging, medical, optical media, electronics, and the automotive industry. In particular, against the backdrop of increasingly severe global climate change and environmental problems, the application of DMCs catalysts in promoting CO2 fixation and conversion has received great attention. By using CO2 as a carbon source to react with epoxides such as propylene oxide to produce polycarbonates, it is not only possible to effectively reduce the content of greenhouse gases in the atmosphere, but also to produce commercially valuable bio-based materials.

[0004] The activity and selectivity of DMCs catalysts can be optimized by adjusting the type, ratio and coordination environment of their constituent metals. For example, zinc and chromium composite DMCs are favored by researchers due to their high efficiency in CO2 / epoxide copolymerization reactions. This type of catalyst can not only increase the molecular weight of the product, but also increase the selectivity for CO2 insertion by regulating the electronic properties of the metal center, thereby reducing the formation of by-products. However, although DMCs catalysts have made significant progress in laboratory-scale research, they still face some challenges in industrial applications, including catalyst stability, recyclability and cost-effectiveness. The present invention prepares a double metal cyanide catalyst by optimizing the materials. Summary of the Invention

[0005] The object of the present invention is to provide a double metal cyanide catalyst and a preparation method thereof to solve the problems raised in the above background technology.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] A method for preparing a double metal cyanide catalyst comprises the following steps:

[0008] Step 1: Dissolve potassium cobalt cyanide in deionized water and stir ultrasonically for 10-15 minutes to obtain solution A;

[0009] Step 2: Mix ferrous sulfate heptahydrate, a complexing agent, and deionized water, and vigorously stir in a constant temperature water bath at 25°C to obtain solution B;

[0010] Step 3: Add solution A dropwise to solution B, stir for 3-4 hours, age for 48-50 hours, and post-treat to obtain a double metal cyanide catalyst.

[0011] More optimally, the complexing agent includes a linear alcohol and a modified silane, wherein the mass ratio of the linear alcohol to the modified silane is 1:(9-11).

[0012] More optimally, the straight-chain alcohol includes one or more of methanol, ethanol, propanol, and butanol, that is, the number of carbon molecules is less than or equal to 4; the straight-chain alcohol contains hydroxyl groups, which can act as ligands to form coordination bonds with metal ions. This coordination effect can enhance the electron density of the metal center and increase the number of available active sites, thereby enhancing the overall catalytic performance of the catalyst.

[0013] More optimally: the preparation process of the modified silane is:

[0014] S1: Dissolve 4-methacrylamidosalicylic acid, acrylic acid, and tetraaminoferric phthalocyanine in deionized water, stir ultrasonically for 3-5 hours, add 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide, heat to 70-80°C, and react for 4-5 hours. The amino groups of tetraaminoferric phthalocyanine react with the carboxyl groups of 4-methacrylamidosalicylic acid and acrylic acid under the action of a catalyst to undergo an amidation reaction to obtain a modifier.

[0015] S2: Mix the modifier, 3-mercaptopropyltrimethoxysilane and ethanol, stir for 30-40 minutes, add azobisisobutyronitrile under a protective atmosphere, raise the temperature to 70-80°C, and react for 5-8 hours to obtain modified silane; wherein, the double bond in the modifier and the thiol of 3-mercaptopropyltrimethoxysilane undergo a click reaction under a protective atmosphere to finally obtain the modified silane; the modified silane is hydrolyzed in water to produce silanol structures, which further react with other silanol groups or metal ions to form a three-dimensional network structure, thereby increasing the number and accessibility of the catalyst active sites; at the same time, the phthalocyanine groups contained therein enhance the electron transfer process of the catalyst, thereby improving the catalytic effect.

[0016] More optimally, the modifier comprises the following components: by weight, 9-11 parts of 4-methylacrylamidosalicylic acid, 1-2 parts of acrylic acid, 9-11 parts of tetraaminoferric phthalocyanine, 0.5-1 parts of 1-ethyl-(3-dimethylaminopropyl)carbodiimide, and 0.5-1 parts of N-hydroxysuccinimide.

[0017] More optimally, the modified silane comprises the following components: 8-10 parts by weight of a modifier, 4-5 parts by weight of 3-mercaptopropyltrimethoxysilane, and 0.5-0.8 parts by weight of azobisisobutyronitrile.

[0018] More optimally, the potassium cobalt cyanide accounts for 0.1-0.2 wt % of solution A.

[0019] More optimally, the solution B comprises the following components: by weight, 1-2 parts of ferrous sulfate heptahydrate, 10-12 parts of a complexing agent, and 1000 parts of deionized water.

[0020] More optimally: in the step three, the specific process of post-treatment is: after aging, washing with water and ethanol for 5-6 times respectively, and then transferring to a vacuum drying oven at 60-70°C and drying for 4-5 hours.

[0021] The present invention modifies 3-mercaptopropyltrimethoxysilane and uses it together with a linear alcohol as a complexing agent to increase the specific surface area of ​​the catalyst, thereby increasing the number of active sites on the catalyst as a whole, thereby effectively activating the reactant molecules and promoting the reaction. The details are as follows:

[0022] First, the amino groups of tetraaminoferric phthalocyanine react with the carboxyl groups of 4-methacrylamidosalicylic acid and acrylic acid under the action of a catalyst to produce an amidation modifier, which then undergoes a click reaction with the double bond of 3-mercaptopropyltrimethoxysilane to ultimately produce a modified silane. The phthalocyanine group in tetraaminoferric phthalocyanine has a large π-electron conjugated system, which helps delocalize electrons within the molecule, thereby reducing the activation energy of electrons and promoting electron transfer during the catalytic process. Simultaneously, the nitrogen atom in the phthalocyanine group can act as an electron donor, providing electrons to the central metal ion through coordination bonds. This facilitates electron transfer from the group to the metal center, reducing the activation energy of the reaction and accelerating the reaction rate. Furthermore, it can form a strong interaction with the substrate, enhancing the adsorption of the substrate on the catalyst surface, and helping to improve the selectivity and activity of the catalytic reaction.

[0023] Second, the modified silane hydrolyzes in water, and the resulting silanol groups bind to metal ions, forming a three-dimensional network. This contributes to the catalyst's porous structure, thereby increasing the number and accessibility of active sites. Furthermore, the modified silane's stable phthalocyanine structure gives the overall catalyst high chemical and thermal stability. This allows it to maintain structural integrity during electron transfer, making it less susceptible to decomposition and enabling high yields to be achieved under relatively mild conditions. DETAILED DESCRIPTION

[0024] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0025] It should be noted that the following parts are by weight, and the purchase manufacturers of all raw materials involved in the present invention are exemplified without any special restrictions: in the following examples, 4-methylacrylamidosalicylic acid CAS is 50512-48-6, and the manufacturer is Shanghai Youhe Biotechnology Co., Ltd.; acrylic acid CAS is 79-10-7, and the manufacturer is Jinan Mingwei Chemical Co., Ltd.; tetraaminoferric phthalocyanine is Q-0342830, and the manufacturer is Xi'an Qiyue Biological; 1-ethyl-(3-dimethylaminopropyl)carbodiimide CAS is 2 5952-53-8, purchased from Merck; N-hydroxysuccinimide CAS number is 6066-82-6, purchased from Merck; 3-mercaptopropyltrimethoxysilane CAS number is 4420-74-0, purchased from Kangdis Chemical Co., Ltd.; potassium cobalt cyanide (K3[Co(CN)6]) CAS number is 13963-58-1, brand is JACS; ferrous sulfate heptahydrate (FeSO4·7H2O) CAS number is 7782-63-0, purchased from Jingzhou Lianda Fine Chemical Co., Ltd.

[0026] Example 1: A method for preparing a double metal cyanide catalyst, comprising the following steps:

[0027] Preparation of modified silane:

[0028] S1: 9 parts of 4-methacrylamidosalicylic acid, 1 part of acrylic acid, and 9 parts of tetraaminoferric phthalocyanine were dissolved in 100 parts of deionized water, and ultrasonically stirred for 3 hours. 0.5 parts of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 0.5 parts of N-hydroxysuccinimide were added, and the mixture was heated to 70°C and reacted for 4 hours to obtain a modifier.

[0029] S2: 8 parts of the modifier, 4 parts of 3-mercaptopropyltrimethoxysilane, and 50 parts of ethanol were mixed and stirred for 30 minutes. Under nitrogen, 0.5 parts of azobisisobutyronitrile were added, the temperature was raised to 70°C, and the reaction was carried out for 5 hours to obtain modified silane.

[0030] Step 1: Dissolve 1 part of potassium cobalt cyanide in 1000 parts of deionized water and stir ultrasonically for 10 minutes to obtain solution A;

[0031] Step 2: Mix 1 part of ferrous sulfate heptahydrate, 10 parts of a complexing agent (1 part of methanol, 9 parts of modified silane), and 500 parts of deionized water, and place the mixture in a 25°C constant temperature water bath with vigorous stirring to obtain solution B;

[0032] Step 3: Add solution A dropwise to solution B, stir for 3 hours, age for 48 hours, wash with water and ethanol 5 times respectively, then transfer to a vacuum drying oven at 60° C. and dry for 4 hours to obtain a double metal cyanide catalyst.

[0033] Example 2: A method for preparing a double metal cyanide catalyst, comprising the following steps:

[0034] Preparation of modified silane:

[0035] S1: 11 parts of 4-methacrylamidosalicylic acid, 2 parts of acrylic acid, and 11 parts of tetraaminoferric phthalocyanine were dissolved in 100 parts of deionized water, and ultrasonically stirred for 5 hours. 1 part of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 1 part of N-hydroxysuccinimide were added, and the mixture was heated to 80°C and reacted for 5 hours to obtain a modifier.

[0036] S2: 10 parts of the modifier, 5 parts of 3-mercaptopropyltrimethoxysilane, and 50 parts of ethanol were mixed and stirred for 40 minutes. Under nitrogen, 0.8 parts of azobisisobutyronitrile were added, the temperature was raised to 80°C, and the reaction was carried out for 8 hours to obtain modified silane.

[0037] Step 1: Dissolve 2 parts of potassium cobalt cyanide in 1000 parts of deionized water and stir ultrasonically for 15 minutes to obtain solution A;

[0038] Step 2: Mix 2 parts of ferrous sulfate heptahydrate, 12 parts of a complexing agent (1 part of methanol, 11 parts of modified silane), and 500 parts of deionized water, and place the mixture in a 25°C constant temperature water bath with vigorous stirring to obtain solution B;

[0039] Step 3: Add solution A dropwise to solution B, stir for 4 hours, age for 50 hours, wash with water and ethanol six times respectively, then transfer to a vacuum drying oven at 70° C. and dry for 5 hours to obtain a double metal cyanide catalyst.

[0040] Example 3: A method for preparing a double metal cyanide catalyst, comprising the following steps:

[0041] Preparation of modified silane:

[0042] S1: 10 parts of 4-methacrylamidosalicylic acid, 1.5 parts of acrylic acid, and 10 parts of tetraaminoferric phthalocyanine were dissolved in 100 parts of deionized water, and ultrasonically stirred for 4 hours. 0.8 parts of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 0.8 parts of N-hydroxysuccinimide were added, and the mixture was heated to 75°C and reacted for 4.5 hours to obtain a modifier.

[0043] S2: 9 parts of the modifier, 4.5 parts of 3-mercaptopropyltrimethoxysilane, and 50 parts of ethanol were mixed and stirred for 35 minutes. Under nitrogen, 0.6 parts of azobisisobutyronitrile were added, and the temperature was raised to 75° C. and reacted for 6 hours to obtain modified silane.

[0044] Step 1: Dissolve 1.5 parts of potassium cobalt cyanide in 1000 parts of deionized water and stir ultrasonically for 15 minutes to obtain solution A;

[0045] Step 2: 1.5 parts of ferrous sulfate heptahydrate, 11 parts of a complexing agent (1 part of methanol, 10 parts of modified silane), and 500 parts of deionized water were mixed and placed in a 25°C constant temperature water bath with vigorous stirring to obtain solution B;

[0046] Step 3: Solution A was added dropwise to solution B, stirred for 4 h, aged for 50 h, washed with water and ethanol 6 times respectively, then transferred to a vacuum drying oven at 65° C. and dried for 4.5 h to obtain a double metal cyanide catalyst.

[0047] Example 4: A method for preparing a double metal cyanide catalyst, comprising the following steps:

[0048] Preparation of modified silane:

[0049] S1: 9 parts of 4-methacrylamidosalicylic acid, 1 part of acrylic acid, and 9 parts of tetraaminoferric phthalocyanine were dissolved in 100 parts of deionized water, and ultrasonically stirred for 3 hours. 0.5 parts of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 0.5 parts of N-hydroxysuccinimide were added, and the mixture was heated to 70°C and reacted for 4 hours to obtain a modifier.

[0050] S2: 8 parts of the modifier, 4 parts of 3-mercaptopropyltrimethoxysilane, and 50 parts of ethanol were mixed and stirred for 30 minutes. Under nitrogen, 0.5 parts of azobisisobutyronitrile were added, the temperature was raised to 70°C, and the reaction was carried out for 5 hours to obtain modified silane.

[0051] Step 1: Dissolve 2 parts of potassium cobalt cyanide in 1000 parts of deionized water and stir ultrasonically for 15 minutes to obtain solution A;

[0052] Step 2: Mix 2 parts of ferrous sulfate heptahydrate, 12 parts of a complexing agent (1 part of methanol, 11 parts of modified silane), and 500 parts of deionized water, and place the mixture in a 25°C constant temperature water bath with vigorous stirring to obtain solution B;

[0053] Step 3: Solution A was added dropwise to solution B, stirred for 4 h, aged for 50 h, washed with water and ethanol 6 times respectively, then transferred to a vacuum drying oven at 65° C. and dried for 4.5 h to obtain a double metal cyanide catalyst.

[0054] Comparative Example 1: Methanol was used alone as the complexing agent. Other details were the same as in Example 4, as follows:

[0055] Step 1: Dissolve 2 parts of potassium cobalt cyanide in 1000 parts of deionized water and stir ultrasonically for 15 minutes to obtain solution A;

[0056] Step 2: Mix 2 parts of ferrous sulfate heptahydrate, 12 parts of a complexing agent (12 parts of methanol), and 500 parts of deionized water, and place the mixture in a 25°C constant temperature water bath with vigorous stirring to obtain solution B;

[0057] Step 3: Solution A was added dropwise to solution B, stirred for 4 h, aged for 50 h, washed with water and ethanol 6 times respectively, then transferred to a vacuum drying oven at 65° C. and dried for 4.5 h to obtain a double metal cyanide catalyst.

[0058] Comparative Example 2: Using modified silane as a complexing agent alone, the other conditions are the same as those in Example 4, as follows:

[0059] Preparation of modified silane:

[0060] S1: 9 parts of 4-methacrylamidosalicylic acid, 1 part of acrylic acid, and 9 parts of tetraaminoferric phthalocyanine were dissolved in 100 parts of deionized water, and ultrasonically stirred for 3 hours. 0.5 parts of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 0.5 parts of N-hydroxysuccinimide were added, and the mixture was heated to 70°C and reacted for 4 hours to obtain a modifier.

[0061] S2: 8 parts of the modifier, 4 parts of 3-mercaptopropyltrimethoxysilane, and 50 parts of ethanol were mixed and stirred for 30 minutes. Under nitrogen, 0.5 parts of azobisisobutyronitrile were added, the temperature was raised to 70°C, and the reaction was carried out for 5 hours to obtain modified silane.

[0062] Step 1: Dissolve 2 parts of potassium cobalt cyanide in 1000 parts of deionized water and stir ultrasonically for 15 minutes to obtain solution A;

[0063] Step 2: Mix 2 parts of ferrous sulfate heptahydrate, 12 parts of a complexing agent (12 parts of modified silane), and 500 parts of deionized water, and place the mixture in a 25°C constant temperature water bath with vigorous stirring to obtain solution B;

[0064] Step 3: Solution A was added dropwise to solution B, stirred for 4 h, aged for 50 h, washed with water and ethanol 6 times respectively, then transferred to a vacuum drying oven at 65° C. and dried for 4.5 h to obtain a double metal cyanide catalyst.

[0065] Comparative Example 3: 3-mercaptopropyltrimethoxysilane was modified without using a modifier, and 3-mercaptopropyltrimethoxysilane and methanol were used as complexing agents. The rest was the same as in Example 4. The details are as follows:

[0066] Step 1: Dissolve 2 parts of potassium cobalt cyanide in 1000 parts of deionized water and stir ultrasonically for 15 minutes to obtain solution A;

[0067] Step 2: Mix 2 parts of ferrous sulfate heptahydrate, 12 parts of a complexing agent (1 part of methanol, 11 parts of modified silane), and 500 parts of deionized water, and place the mixture in a 25°C constant temperature water bath with vigorous stirring to obtain solution B;

[0068] Step 3: Solution A was added dropwise to solution B, stirred for 4 h, aged for 50 h, washed with water and ethanol 6 times respectively, then transferred to a vacuum drying oven at 65° C. and dried for 4.5 h to obtain a double metal cyanide catalyst.

[0069] Comparative Example 4: Preparation of a single FeCo bimetallic catalyst without adding a complexing agent:

[0070] Step 1: Dissolve 2 parts of potassium cobalt cyanide in 1000 parts of deionized water and stir ultrasonically for 15 minutes to obtain solution A;

[0071] Step 2: Mix 2 parts of ferrous sulfate heptahydrate and 500 parts of deionized water, and place in a 25°C constant temperature water bath with vigorous stirring to obtain solution B;

[0072] Step 3: Solution A was added dropwise to solution B, stirred for 4 h, aged for 50 h, washed with water and ethanol 6 times respectively, then transferred to a vacuum drying oven at 65° C. and dried for 4.5 h to obtain a double metal cyanide catalyst.

[0073] Testing experiment: 0.1 g of the catalysts obtained in the Examples and Comparative Examples and 30 mL of propylene oxide were weighed and added to a reactor. The reactor was pressurized to 50 bar with carbon dioxide and the reaction was carried out at 70°C with vigorous stirring for 24 hours. After the reaction, the reactor was cooled in an ice-water bath, and the remaining carbon dioxide was slowly released to prevent loss of the epoxide. The crude product was then filtered and dissolved in dichloromethane. The solution was then filtered through bluestone under vacuum conditions. The polymer was then slowly added to ethanol to precipitate. The polymer was isolated by vacuum filtration and dried at 80°C overnight. The weight was weighed and the carbon dioxide fixation rate was calculated. The obtained data are shown in the table below:

[0074]

[0075] Table 1

[0076] Conclusion: Compared with Comparative Example 4, Examples 1-4 increase the specific surface area of ​​the catalyst by modifying 3-mercaptopropyltrimethoxysilane and acting as a complexing agent together with a straight-chain alcohol, thereby increasing the number of active sites of the catalyst as a whole, thereby effectively activating the reactant molecules and promoting the reaction.

[0077] Comparative Example 1 uses methanol alone as a complexing agent. The monohydric alcohol contains hydroxyl groups, which can serve as a ligand to form a coordination bond with the metal ion. This coordination effect can change the electron density and available active sites of the metal center, thereby affecting the catalytic performance of the catalyst. However, the lack of the modified silane to play a role reduces the thermal stability of the catalyst, making it easy to lose it during the catalytic reaction, thereby reducing the catalytic performance.

[0078] Comparative Example 2 uses only modified silane as a complexing agent, and its carbon dioxide fixation rate is increased compared to Comparative Example 1. This is because the phthalocyanine group contained in the modified silane has a large π-electron conjugated system, which helps to delocalize electrons within the molecule, thereby reducing the activation energy of electrons and promoting the transfer of electrons in the catalyst during the catalytic process. At the same time, the nitrogen atom in the phthalocyanine group can act as an electron donor, providing electrons to the central metal ion through a coordination bond, which helps transfer electrons from the group to the metal center, reducing the activation energy of the reaction and accelerating the reaction rate. However, compared with Example 4, the synergistic effect of the straight-chain alcohol is lacking, and its catalytic performance is also reduced.

[0079] Comparative Example 3 does not use a modifier to modify 3-mercaptopropyltrimethoxysilane, which is better than the lack of phthalocyanine groups in the modifier, so that the overall stability and catalytic efficiency of the catalyst are reduced, and therefore, its carbon dioxide fixation rate decreases.

[0080] Throughout the specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0081] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for preparing a double metal cyanide catalyst, characterized in that: The following steps are involved: Step 1: Dissolve potassium cobalt cyanide in deionized water and stir ultrasonically for 10-15 minutes to obtain solution A; Step 2: Mix ferrous sulfate heptahydrate, a complexing agent, and deionized water, and place in a constant temperature water bath at 25°C with vigorous stirring to obtain solution B; Step 3: adding solution A dropwise to solution B, stirring for 3-4 hours, aging for 48-50 hours, and post-treating to obtain a double metal cyanide catalyst; The complexing agent comprises a linear alcohol and a modified silane, wherein the mass ratio of the linear alcohol to the modified silane is 1:(9-11); The linear alcohol includes one or more of methanol, ethanol, propanol, and butanol; The preparation process of the modified silane is: S1: Dissolve 4-methacrylamidosalicylic acid, acrylic acid, and tetraaminoferric phthalocyanine in deionized water, stir ultrasonically for 3-5 hours, add 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide, heat to 70-80°C, and react for 4-5 hours to obtain a modifier; S2: Mix the modifier, 3-mercaptopropyltrimethoxysilane, and ethanol, stir for 30-40 minutes, add azobisisobutyronitrile under a protective atmosphere, heat to 70-80°C, and react for 5-8 hours to obtain modified silane.

2. The method for preparing a double metal cyanide catalyst according to claim 1, wherein: The modifier comprises the following components: by weight, 9-11 parts of 4-methylacrylamidosalicylic acid, 1-2 parts of acrylic acid, 9-11 parts of tetraaminoferric phthalocyanine, 0.5-1 part of 1-ethyl-(3-dimethylaminopropyl)carbodiimide, and 0.5-1 part of N-hydroxysuccinimide.

3. The method for preparing a double metal cyanide catalyst according to claim 1, wherein: The modified silane comprises the following components: 8-10 parts of a modifier, 4-5 parts of 3-mercaptopropyltrimethoxysilane, and 0.5-0.8 parts of azobisisobutyronitrile, by weight.

4. The method for preparing a double metal cyanide catalyst according to claim 1, wherein: The potassium cobalt cyanide accounts for 0.1-0.2 wt % of solution A.

5. The method for preparing a double metal cyanide catalyst according to claim 1, wherein: The solution B comprises the following components: by weight, 1-2 parts of ferrous sulfate heptahydrate, 10-12 parts of a complexing agent, and 1000 parts of deionized water.

6. The method for preparing a double metal cyanide catalyst according to claim 1, wherein: In the step 3, the specific process of post-treatment is as follows: after aging, washing with water and ethanol for 5-6 times respectively, and then transferring to a vacuum drying oven at 60-70° C. and drying for 4-5 hours.

7. A double metal cyanide catalyst obtained by the preparation method of a double metal cyanide catalyst according to any one of claims 1 to 6.

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