Double-metal cyanide catalyst and preparation method thereof

Abstract

The invention relates to the field of catalyst preparation, in particular to a double-metal cyanide catalyst and a preparation method thereof. Comprising the following steps that 1, cobalt potassium cyanide is dissolved in deionized water, ultrasonic stirring is conducted for 10-15 min, and a solution A is obtained; 2, ferrous sulfate heptahydrate, a complexing agent and deionized water are mixed and placed in a constant-temperature water bath at the temperature of 25 DEG C to be violently stirred, and a solution B is obtained; and 3, dropwise adding the solution A into the solution B, stirring for 3-4 hours, aging for 48-50 hours, and carrying out post-treatment to obtain the double-metal cyanide catalyst. The preparation method has the beneficial effects that the 3-mercaptopropyltrimethoxysilane is modified, and the 3-mercaptopropyltrimethoxysilane and the straight-chain alcohol serve as complexing agents together, so that the specific surface area of the catalyst is increased, the number of active sites of the whole catalyst is increased, reactant molecules can be effectively activated, and the reaction is promoted.

Description

Technical Field

[0001] The 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 (DMCs) catalysts are a class of compounds with special structures and catalytic properties, consisting of two different metal ions and cyanide ligands. Due to their unique electronic properties and tunable structural characteristics, this type of catalyst has shown broad application potential in multiple chemical fields, especially in promoting environmentally friendly chemical reactions.

[0003] DMCs were first discovered in the 1970s and were used in industrial polymer production, such as the synthesis of polyesters and polyethers. Over time, scientists discovered that DMCs have the potential to catalyze CO 2 DMCs have remarkable activity and selectivity in the conversion and ring-opening polymerization of epoxides. These reactions are crucial for the synthesis of biodegradable polycarbonate materials, which have a wide range of applications in packaging, medical, optical media, electronics and automotive industries. Especially in the context of global climate change and increasingly severe environmental problems, DMCs catalysts have played an important role in promoting CO 2 The applications in fixation and conversion have received great attention. 2 As a carbon source, reacting with epoxides such as propylene oxide to produce polycarbonate can not only effectively reduce the greenhouse gas content in the atmosphere, but also produce bio-based materials with commercial value.

[0004] The activity and selectivity of DMCs catalysts can be optimized by adjusting the types, ratios, and coordination environments of their constituent metals. 2 / epoxide copolymerization reaction. This type of catalyst can not only increase the molecular weight of the product, but also increase the CO by regulating the electronic properties of the metal center. 2 The selectivity of insertion can reduce the generation 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 place in a 25° C. constant temperature water bath and vigorously stir to obtain solution B;

[0010] Step 3: Add solution A dropwise into 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, wherein the amino group of tetraaminoferric phthalocyanine and the carboxyl group of 4-methacrylamidosalicylic acid and acrylic acid undergo amidation reaction under the action of a catalyst to obtain a modifier;

[0015] S2: Mix the modifier, 3-mercaptopropyltrimethoxysilane and ethanol, stir for 30-40 minutes, add azobisisobutyronitrile under a protective atmosphere, heat to 70-80°C, react for 5-8 hours to obtain modified silane; wherein, the double bonds in the modifier and the thiol of 3-mercaptopropyltrimethoxysilane undergo a click reaction under a protective atmosphere to finally obtain 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 tetraaminoferrophthalocyanine, 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: by weight, 8-10 parts of a modifier, 4-5 parts of 3-mercaptopropyltrimethoxysilane, and 0.5-0.8 parts 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 4-5h.

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

[0022] First, the amino group of tetraaminoferric phthalocyanine reacts with the carboxyl group of 4-methylacrylamide salicylic acid and acrylic acid under the action of a catalyst to obtain a modifier; and then a click reaction is carried out with the double bond of 3-mercaptopropyltrimethoxysilane to finally obtain a modified silane. Among them, the phthalocyanine group in tetraaminoferric phthalocyanine has a large π electron conjugated system, which helps the delocalization of electrons inside 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 and provide electrons to the central metal ion through a coordination bond, which helps the electrons transfer from the group to the metal center, reduces the activation energy of the reaction, accelerates the reaction rate, and can form a strong interaction with the substrate, enhancing the adsorption of the substrate on the catalyst surface, which helps to improve the selectivity and activity of the catalytic reaction.

[0023] Second, the modified silane is hydrolyzed in water, and the formed silanol groups combine with metal ions to form a three-dimensional network structure, which helps to form a porous structure of the catalyst, thereby increasing the number and accessibility of active sites. At the same time, the modified silane has a stable phthalocyanine structure, which makes the overall catalyst have high chemical and thermal stability, which enables them to maintain structural integrity during the electron transfer process and is not easy to decompose; and can obtain high yields in a milder environment. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work 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 embodiments, 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.; tetraaminoferrophthalocyanine item number is Q-0342830, and the manufacturer is Xi'an Qiyue Biology; 1-ethyl-(3-dimethylaminopropyl)carbodiimide CAS is 25952-53-8, and the purchase manufacturer is Merck; N-hydroxysuccinimide CAS is 6066-82-6, and the purchase manufacturer is Merck; 3-mercaptopropyltrimethoxysilane CAS is 4420-74-0, and the purchase manufacturer is Condis Chemical Co., Ltd.; potassium cobalt cyanide (K 3 [Co(CN) 6 ])CAS is 13963-58-1, brand is JACS; ferrous sulfate heptahydrate (FeSO 4 7H 2 O)CAS is 7782-63-0, and the manufacturer is Jingzhou Lianda Fine Chemical Co., Ltd.

[0026] Embodiment 1: A method for preparing a double metal cyanide catalyst comprises 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, and 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: 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 were mixed, and the mixture was placed in a constant temperature water bath at 25° C. and stirred vigorously to obtain a solution B;

[0032] Step 3: Add solution A dropwise into solution B, stir for 3 hours, age for 48 hours, wash with water and ethanol for 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] Embodiment 2: A method for preparing a double metal cyanide catalyst comprises 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, and 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: 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 were mixed, and the mixture was placed in a constant temperature water bath at 25° C. and stirred vigorously to obtain a solution B;

[0039] Step 3: Add solution A dropwise into solution B, stir for 4 hours, age for 50 hours, wash with water and ethanol for 6 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] Embodiment 3: A method for preparing a double metal cyanide catalyst comprises 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, and 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, the temperature was raised to 75° C., and the reaction was carried out 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 the mixture was placed in a constant temperature water bath at 25° C. and stirred vigorously to obtain a solution B;

[0046] Step 3: Add solution A dropwise into solution B, stir for 4 hours, age for 50 hours, wash with water and ethanol for 6 times respectively, then transfer to a vacuum drying oven at 65° C., and dry for 4.5 hours to obtain a double metal cyanide catalyst.

[0047] Embodiment 4: A method for preparing a double metal cyanide catalyst comprises 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, and 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: 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 were mixed, and the mixture was placed in a constant temperature water bath at 25° C. and stirred vigorously to obtain a solution B;

[0053] Step 3: Add solution A dropwise into solution B, stir for 4 hours, age for 50 hours, wash with water and ethanol for 6 times respectively, then transfer to a vacuum drying oven at 65° C., and dry for 4.5 hours to obtain a double metal cyanide catalyst.

[0054] Comparative Example 1: Methanol is used alone as the complexing agent, and the rest is the same as Example 4, specifically 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: 2 parts of ferrous sulfate heptahydrate, 12 parts of a complexing agent (12 parts of methanol), and 500 parts of deionized water were mixed, and the mixture was placed in a 25° C. constant temperature water bath and stirred vigorously to obtain a solution B;

[0057] Step 3: Add solution A dropwise into solution B, stir for 4 hours, age for 50 hours, wash with water and ethanol for 6 times respectively, then transfer to a vacuum drying oven at 65° C., and dry for 4.5 hours to obtain a double metal cyanide catalyst.

[0058] Comparative Example 2: Using only modified silane as a complexing agent, the rest is the same as Example 4, specifically 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, and 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: 2 parts of ferrous sulfate heptahydrate, 12 parts of a complexing agent (12 parts of modified silane), and 500 parts of deionized water were mixed, and the mixture was placed in a constant temperature water bath at 25° C. and stirred vigorously to obtain a solution B;

[0064] Step 3: Add solution A dropwise into solution B, stir for 4 hours, age for 50 hours, wash with water and ethanol for 6 times respectively, then transfer to a vacuum drying oven at 65° C., and dry for 4.5 hours 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, and the rest was the same as 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: 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 were mixed, and the mixture was placed in a constant temperature water bath at 25° C. and stirred vigorously to obtain a solution B;

[0068] Step 3: Add solution A dropwise into solution B, stir for 4 hours, age for 50 hours, wash with water and ethanol for 6 times respectively, then transfer to a vacuum drying oven at 65° C., and dry for 4.5 hours to obtain a double metal cyanide catalyst.

[0069] Comparative Example 4: Preparation process 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 and stir vigorously to obtain solution B;

[0072] Step 3: Add solution A dropwise into solution B, stir for 4 hours, age for 50 hours, wash with water and ethanol for 6 times respectively, then transfer to a vacuum drying oven at 65° C., and dry for 4.5 hours to obtain a double metal cyanide catalyst.

[0073] Detection experiment: Weigh 0.1g of the catalyst obtained in the embodiment and comparative example and 30mL of propylene oxide into the reactor, pressurize to 50bar with carbon dioxide, react at 70°C, and stir vigorously for 24h; after the reaction, cool the reactor in an ice water bath, slowly release the remaining carbon dioxide to prevent the loss of epoxide, then filter, dissolve the obtained crude product in dichloromethane, filter through bluestone under vacuum conditions, then slowly add the solution to ethanol to precipitate the polymer, separate the polymer by vacuum filtration, and dry at 80°C overnight. Weigh, calculate the carbon dioxide fixation rate, and the obtained data are shown in the following table:

[0074]

[0075] Table 1

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

[0077] Comparative Example 1 uses methanol as a complexing agent alone. 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 modified silane to play a role together reduces the thermal stability of the catalyst, and it is easy to be lost in the catalytic reaction, thereby reducing the catalytic performance.

[0078] Comparative Example 2 uses modified silane as a complexing agent alone, and its carbon dioxide fixation rate is increased compared with Comparative Example 1, because the phthalocyanine group contained in the modified silane has a larger π electron conjugated system, which helps the delocalization of electrons inside 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 to provide electrons to the central metal ion through a coordination bond, which helps the electrons transfer from the group to the metal center, reduces the activation energy of the reaction, and accelerates 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] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0081] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is 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 can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope 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 25° C. constant temperature water bath and vigorously stir to obtain solution B; Step 3: Add solution A dropwise into solution B, stir for 3-4 hours, age for 48-50 hours, and post-treat to obtain a double metal cyanide catalyst.

2. The method for preparing a double metal cyanide catalyst according to claim 1, characterized in that: The complexing agent comprises straight-chain alcohol and modified silane, wherein the mass ratio of the straight-chain alcohol to the modified silane is 1:(9-11).

3. The method for preparing a double metal cyanide catalyst according to claim 2, characterized in that: The straight-chain alcohol includes one or more of methanol, ethanol, propanol and butanol.

4. The method for preparing a double metal cyanide catalyst according to claim 2, characterized in that: 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, react for 4-5 hours, and 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, react for 5-8 hours, and obtain modified silane.

5. The method for preparing a double metal cyanide catalyst according to claim 4, characterized in that: 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 tetraaminoferrophthalocyanine, 0.5-1 parts of 1-ethyl-(3-dimethylaminopropyl)carbodiimide, and 0.5-1 parts of N-hydroxysuccinimide.

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

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

8. The method for preparing a double metal cyanide catalyst according to claim 1, characterized in that: 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.

9. The method for preparing a double metal cyanide catalyst according to claim 1, characterized in that: In the step 3, 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.

10. A double metal cyanide catalyst obtained according to the preparation method of a double metal cyanide catalyst according to any one of claims 1 to 9.

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