Alloy-modified nickel foam catalysts, preparation methods and applications

Abstract

This invention relates to the field of modified nickel foam catalysts for catalyzing hydrosilylation reactions, and discloses alloy-modified nickel foam catalysts, preparation methods, and applications. Specifically, it involves: synthesizing ligand-type silane coupling agents; grafting the ligand-type silane coupling agent onto the surface of nickel foam based on the silanol-hydroxyl condensation reaction mechanism to obtain surface-ligand-modified nickel foam; using the ligand-type silane coupling agent grafted onto the surface of nickel foam and imidazole monomers as composite ligands, and assembling a nickel-platinum alloy and dissolved nickel ions on the surface of nickel foam through coordination to form a MOF material with the nickel-platinum alloy as the core, thereby obtaining an alloy-modified nickel foam catalyst. This catalyst product exhibits excellent catalytic activity in hydrosilylation reactions.

Description

Technical Field

[0001] This invention relates to the field of modified nickel foam catalysts for catalyzing hydrosilylation reactions, specifically alloy-modified nickel foam catalysts, their preparation methods, and applications. Background Technology

[0002] Hydrosilylation is the most commonly used Si-C bond construction method in organosilicon chemistry. In industrial production, the catalysts used to catalyze hydrosilylation are mainly homogeneous catalysts represented by Speier catalysts and Karstedt catalysts. These catalysts generally have problems such as difficulty in separating them from the reaction system after use, high cost, and poor catalytic selectivity.

[0003] Nickel foam, as a three-dimensional porous metallic material, possesses characteristics such as high porosity, large specific surface area, excellent stability, low cost, and ease of preparation and recycling. While metallic nickel itself exhibits catalytic activity for hydrosilylation reactions, the adsorption and activation capacity of metallic nickel in nickel foam for Si-H bonds is weak, making it difficult to provide the electronic environment required for efficient reactions. Furthermore, although nickel foam has a large macroscopic surface area, the number of highly active sites (such as edges, steps, and defect sites) on the surface is limited, with most being atomic terraces (platforms) with low catalytic activity. This restricts its overall catalytic efficiency.

[0004] Therefore, nickel foam usually needs to be modified to improve its catalytic performance and meet the needs of practical applications. Summary of the Invention

[0005] This invention assembles a nickel-platinum alloy-based MOF material on the surface of nickel foam, thereby introducing the noble metal platinum with high catalytic activity sites and increasing the number of nickel active sites. The resulting alloy-modified nickel foam catalyst exhibits excellent catalytic activity in the hydrosilylation reaction.

[0006] The preparation method of alloy-modified nickel foam catalyst includes the following steps:

[0007] Step 1: Synthesize ligand-type silane coupling agents;

[0008] Step 2: Based on the silanol-hydroxyl condensation reaction mechanism, a ligand-type silane coupling agent is grafted onto the surface of nickel foam rich in hydroxyl functional groups to obtain surface ligand-modified nickel foam.

[0009] Step 3: Using a ligand-type silane coupling agent grafted onto the surface of nickel foam and an imidazole monomer as a composite ligand, the composite ligand, along with the nickel-platinum alloy and the dissolved nickel ions, coordinates with each other on the surface of the nickel foam to assemble a MOF material with the nickel-platinum alloy as the core, thus obtaining an alloy-modified nickel foam catalyst.

[0010] Preferably, the preparation method of the ligand-type silane coupling agent is as follows:

[0011] Intermediate 1 is generated by nucleophilic substitution reaction between the -NH2 functional group of 1 molar equivalent melamine and the bromine functional group of 0.91-0.95 molar equivalent bromoalkenyl monomer.

[0012] Intermediate 2 is generated by a Schiff base condensation reaction between the -NH2 functional group of 1 molar equivalent intermediate 1 and the aldehyde functional group of 2.05-2.09 molar equivalent 2-imidazolium formaldehyde.

[0013] In the presence of a photoinitiator, a ligand-type silane coupling agent is generated by a click reaction between the alkenyl functional group of 1 molar equivalent intermediate 2 and the mercapto functional group of 1.01-1.05 molar equivalent 3-mercaptopropyltrimethylsilane under ultraviolet light.

[0014] Preferably, the bromoalkenyl monomer is one of 3-bromo-1-propene, 4-bromo-1-butene, 5-bromo-1-pentene, 6-bromo-1-hexene, 7-bromo-1-heptene, and 8-bromo-1-octene.

[0015] Preferably, the photoinitiator is one of 2,2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropanone, and 2,2-diethoxyacetophenone.

[0016] The alloy-modified nickel foam catalyst prepared according to the above method;

[0017] Preferably, the alloy-modified nickel foam catalyst has the following formulation: 4 parts by weight of nickel foam, 2 parts by weight of ligand-type silane coupling agent, 8 parts by weight of imidazole monomer, and 0.5-1.5 parts by weight of nickel-platinum alloy.

[0018] Preferably, the imidazole monomer is one of 2-methylimidazole, 2-ethyl-4-methylimidazole, and 2-ethylimidazole.

[0019] Preferably, the particle size of the nickel-platinum alloy is 500-2000 mesh.

[0020] Preferably, the nickel foam has a pore size of 80-100 PPI and a bulk density of 0.08-0.12 g / cm³. 3 The porosity is 95-99%.

[0021] Beneficial effects:

[0022] Based on molecular design mechanism, this invention synthesizes ligand-type silane coupling agent and uses ligand-type silane coupling agent to perform surface grafting modification treatment on nickel foam to obtain surface ligand-modified nickel foam.

[0023] Using ligand-type silane coupling agent and 2-methylimidazole grafted onto the surface of nickel foam as composite ligands, the composite ligands, nickel ions (dissolved from nickel-platinum alloy in solvent) and the nickel-platinum alloy itself are coordinated to form MOF material with nickel-platinum alloy as the core on the surface of nickel foam, thus preparing alloy-modified nickel foam catalyst.

[0024] The hydrosilylation reaction of trichlorosilane and 3-chloropropene was catalyzed by alloy-modified foamed nickel catalyst to produce 3-chloropropyltrichlorosilane. Compared with unmodified foamed nickel, the yield of 3-chloropropyltrichlorosilane was increased to over 92%.

[0025] Polyether-modified silicone oil was generated by hydrosilylation reaction of hydrogen-containing silicone oil and polyethylene glycol monoallyl ether using alloy-modified nickel foam catalyst. Compared with unmodified nickel foam, the hydrosilylation conversion rate of polyether-modified silicone oil was increased to over 90%.

[0026] Compared with conventional commercial Karstedt catalysts with the same platinum content, alloy-modified nickel foam catalysts show significantly improved catalytic activity for hydrosilylation reactions;

[0027] The alloy-modified nickel foam catalyst prepared by this invention exhibits excellent catalytic activity in the hydrosilylation reaction. Detailed Implementation

[0028] Example 1:

[0029] Synthetic ligand-type silane coupling agents, including but not limited to the following reaction formulas and reaction steps:

[0030] ;

[0031] Step 1: Using melamine as the base material, a nucleophilic substitution reaction is carried out between the -NH2 functional group of 1 molar equivalent of melamine and the bromine functional group of 0.92 molar equivalent of bromoalkenyl monomer to generate intermediate 1;

[0032] Among them, bromoalkenyl monomers ( The following raw materials can be selected:

[0033] 3-Bromo-1-propene: ;

[0034] 4-Bromo-1-butene: ;

[0035] 5-Bromo-1-pentene: ;

[0036] 6-Bromo-1-hexene: ;

[0037] 7-Bromo-1-hepten: ;

[0038] 8-Bromo-1-octene: ;

[0039] Step 2: Intermediate 2 is generated by a Schiff base condensation reaction between the -NH2 functional group of 1 molar equivalent intermediate 1 and the aldehyde functional group of 2.06 molar equivalent 2-imidazolium formaldehyde.

[0040] Step 3: In the presence of a photoinitiator, the alkenyl functional group of 1 molar equivalent intermediate 2 and the mercapto functional group of 1.03 molar equivalent 3-mercaptopropyltrimethylsilane undergo a click reaction under ultraviolet light to generate a ligand-type silane coupling agent.

[0041] The photoinitiator can be selected from one of 2,2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropanone, and 2,2-diethoxyacetophenone; in this embodiment, 2,2-dimethoxy-2-phenylacetophenone is selected.

[0042] Using a method for synthesizing ligand-type silane coupling agents, when 5-bromo-1-pentene is selected as the bromoalkenyl monomer, a ligand-type silane coupling agent M is synthesized, with the following chemical structural formula:

[0043] ;

[0044] The specific experimental steps for synthesizing the ligand-type silane coupling agent M are as follows:

[0045] Under nitrogen protection, 2.5 g of melamine and 30 mL of anhydrous N,N-dimethylformamide were added to a three-necked flask. The mixture was heated to 50 °C and stirred for 30 min to dissolve. After cooling to 30 °C, 20 mL of anhydrous N,N-dimethylformamide solution containing 2.7 g of 5-bromo-1-pentene and 1.5 mL of triethylamine were added dropwise to the three-necked flask. The mixture was heated to 70 °C and stirred for 6 h. After cooling to room temperature, the mixture was evaporated under reduced pressure and dried to obtain intermediate 1.

[0046] Under nitrogen protection, 1.9 g of intermediate 1 and 20 mL of anhydrous N,N-dimethylformamide were added to a three-necked flask and stirred at room temperature for 30 min to dissolve. Then, 20 mL of anhydrous N,N-dimethylformamide solution containing 2.0 g of 2-imidazolium formaldehyde and two drops of glacial acetic acid were added dropwise to the three-necked flask. The mixture was heated to 60 °C and stirred for 8 h. After cooling to room temperature, the mixture was evaporated under reduced pressure and dried to obtain intermediate 2.

[0047] Under nitrogen protection, 1.8 g of intermediate 2, 0.1 g of 2,2-dimethoxy-2-phenylacetophenone, and 50 mL of anhydrous N,N-dimethylformamide were added to a three-necked flask and stirred at room temperature for 30 min to dissolve. Under UV irradiation (365 nm, 10 cm), 1.0 mL of 3-mercaptopropyltrimethylsilane was added dropwise to the three-necked flask using a constant pressure funnel. After the addition was complete, the reaction was stirred under UV irradiation for another 30 min. The mixture was then evaporated under reduced pressure and dried to obtain ligand-type silane coupling agent M.

[0048] The 1H NMR characterization of the ligand-type silane coupling agent M is as follows: 1 H NMR (DMSO-d6, 400MHz) δ: 0.78-0.81(t, 2H), 1.39-1.54(m, 4H), 1.65-1.77(m, 4H), 2.45-2.48(t, 2H), 2.56-2.60(t , 2H), 3.12-3.17(m, 2H), 3.57(s, 9H), 7.23-7.31(m, 5H), 8.31(s, 2H), 10.92-10.94(d, 2H).

[0049] Example 2:

[0050] The alloy-modified nickel foam catalyst I was prepared with the following formula: 4 parts by weight of nickel foam, 2 parts by weight of ligand-type silane coupling agent M, 8 parts by weight of 2-methylimidazole, and 1 part by weight of nickel-platinum alloy. The preparation process is as follows:

[0051] (1) Preparation of surface ligand-modified nickel foam: The preparation method is as follows: The surface of nickel foam is modified by using a ligand-type silane coupling agent M. The silanol functional groups obtained by the hydrolysis reaction of the silanol functional groups of the silanol coupling agent M undergo a dehydration condensation reaction with the hydroxyl functional groups on the surface of the hydrophilic nickel foam to obtain surface ligand-modified nickel foam. The specific preparation steps are as follows:

[0052] Add 2g of ligand-type silane coupling agent M, 20mL of anhydrous ethanol and 5mL of deionized water to a beaker, stir at room temperature for 1h to obtain the hydrolysis reaction solution of ligand-type silane coupling agent M.

[0053] First, 4g of nickel foam (5cm×8cm×1cm, purchased from Jilin Newstar Metal Materials Co., Ltd., with a pore size of 90PPI and a bulk density of 0.1g / cm³) was... 3(With a porosity of 98%), it is immersed in a 5wt% dilute hydrochloric acid solution and kept for 10 minutes to remove surface oxides and impurities. Then, it is immersed in a mixed solution of deionized water and anhydrous ethanol (volume ratio of deionized water and anhydrous ethanol is 1:1) and ultrasonically cleaned for 30 minutes. It is then vacuum dried at 50°C for 6 hours. Finally, it is immersed in the prepared hydrolysis reaction solution of ligand-type silane coupling agent M and ultrasonically reacted at 60°C for 30 minutes. After that, it is taken out and vacuum dried at 50°C for 2 hours to obtain surface ligand-modified nickel foam.

[0054] (2) Preparation of alloy-modified nickel foam catalyst I: The preparation method is as follows: using a ligand-type silane coupling agent and 2-methylimidazole grafted onto the surface of nickel foam as composite ligands, the composite ligands and nickel ions dissolved in the nickel-platinum alloy in the solvent (the activity of metallic nickel is much greater than that of platinum, so a small amount of nickel ions will be dissolved in the nickel-platinum alloy in the solvent due to the presence of oxygen and water, while metallic platinum remains stable) and the nickel-platinum alloy itself are coordinated on the surface of nickel foam to carry out the MOF material assembly process with the nickel-platinum alloy as the core, so as to obtain alloy-modified nickel foam catalyst I. The specific preparation steps are as follows:

[0055] 1g of nickel-platinum alloy (purchased from Nanjing Jike Biotechnology Co., Ltd., model JK-25-001, particle size 1000 mesh), 20mL of anhydrous N,N-dimethylformamide and 1mL of deionized water were added to a beaker, ultrasonically dispersed for 30min, heated to 50℃ and stirred for 1h to obtain nickel-platinum alloy dispersion I.

[0056] 8g of 2-methylimidazole and 100mL of anhydrous N,N-dimethylformamide were added to a beaker and stirred at room temperature until completely dissolved to form a 2-methylimidazole dispersion. The surface ligand modified nickel foam prepared in (1) was immersed in it, and after sonication for 30min, the prepared nickel-platinum alloy dispersion I was added. The mixture was sonicated for another 2h and then transferred to a stainless steel reactor lined with polytetrafluoroethylene. The temperature was raised to 140℃ and kept at that temperature for 24h. The mixture was then cooled to room temperature, removed, washed with ethanol, and dried under vacuum at 50℃ for 8h to obtain alloy modified nickel foam catalyst I.

[0057] Example 3:

[0058] The alloy-modified nickel foam catalyst II was prepared with the following formula: 4 parts by weight of nickel foam, 2 parts by weight of ligand-type silane coupling agent M, 8 parts by weight of 2-methylimidazole, and 0.5 parts by weight of nickel-platinum alloy. The preparation process is as follows:

[0059] (1) Prepare surface ligand modified nickel foam, which is exactly the same as the preparation method and specific preparation steps of surface ligand modified nickel foam in Example 2;

[0060] (2) Prepare alloy-modified nickel foam catalyst II, which is prepared in the same way as alloy-modified nickel foam catalyst I in Example 2. The specific preparation steps are as follows:

[0061] 0.5g of nickel-platinum alloy (purchased from Nanjing JK Biotechnology Co., Ltd., model JK-25-001, particle size 1000 mesh), 20mL of anhydrous N,N-dimethylformamide and 1mL of deionized water were added to a beaker, ultrasonically dispersed for 30min, heated to 50℃ and stirred for 1h to obtain nickel-platinum alloy dispersion II.

[0062] 8g of 2-methylimidazole and 100mL of anhydrous N,N-dimethylformamide were added to a beaker and stirred at room temperature until completely dissolved to form a 2-methylimidazole dispersion. The surface ligand modified nickel foam prepared in (1) was immersed into it, and after sonication for 30min, the prepared nickel-platinum alloy dispersion II was added. The mixture was sonicated for another 2h and then transferred to a stainless steel reactor lined with polytetrafluoroethylene. The temperature was raised to 140℃ and kept at that temperature for 24h. The mixture was then cooled to room temperature, removed, washed with ethanol, and dried under vacuum at 50℃ for 8h to obtain alloy modified nickel foam catalyst II.

[0063] Example 4:

[0064] The alloy-modified nickel foam catalyst III was prepared with the following formula: 4 parts by weight of nickel foam, 2 parts by weight of ligand-type silane coupling agent M, 8 parts by weight of 2-methylimidazole, and 1.5 parts by weight of nickel-platinum alloy. The preparation process is as follows:

[0065] (1) Prepare surface ligand modified nickel foam, which is exactly the same as the preparation method and specific preparation steps of surface ligand modified nickel foam in Example 2;

[0066] (2) The alloy-modified nickel foam catalyst III was prepared using the same method as the alloy-modified nickel foam catalyst I in Example 2. The specific preparation steps are as follows:

[0067] 1.5g of nickel-platinum alloy (purchased from Nanjing JK Biotechnology Co., Ltd., model JK-25-001, particle size 1000 mesh), 20mL of anhydrous N,N-dimethylformamide and 1mL of deionized water were added to a beaker, ultrasonically dispersed for 30min, heated to 50℃ and stirred for 1h to obtain nickel-platinum alloy dispersion III.

[0068] 8g of 2-methylimidazole and 100mL of anhydrous N,N-dimethylformamide were added to a beaker and stirred at room temperature until completely dissolved to form a 2-methylimidazole dispersion. The surface ligand modified nickel foam prepared in (1) was immersed into it, and after sonication for 30min, the prepared nickel-platinum alloy dispersion III was added. The mixture was sonicated for another 2h and then transferred to a stainless steel reactor lined with polytetrafluoroethylene. The temperature was raised to 140℃ and kept at that temperature for 24h. The mixture was then cooled to room temperature, removed, washed with ethanol, and dried under vacuum at 50℃ for 8h to obtain alloy modified nickel foam catalyst III.

[0069] Example 5:

[0070] The platinum content in the alloy-modified foamed nickel catalyst was tested using an ICP emission spectrometer with an argon flow rate of 12 L / min, an auxiliary gas flow rate of 1 L / min, and an atomizing gas flow rate of 1 L / min.

[0071] The platinum content test results of the alloy-modified foamed nickel catalyst are shown in Table 1.

[0072] Table 1. Test results of platinum content in alloy-modified nickel foam catalysts.

[0073] Product Categories Platinum content (mg / g) Alloy-modified nickel foam catalyst I 31.6 Alloy-modified nickel foam catalyst I and II 15.3 Alloy-modified foamed nickel catalyst III 40.8

[0074] Example 6:

[0075] Experiment 1: Application of alloy-modified nickel foam catalyst: Using alloy-modified nickel foam catalyst as a catalyst for the hydrosilylation reaction of trichlorosilane and 3-chloropropene, the Si-H functional groups of trichlorosilane and the alkenyl functional groups of 3-chloropropene are catalyzed by the alloy-modified nickel foam catalyst to produce 3-chloropropyltrichlorosilane. The chemical reaction formula is as follows:

[0076] ;

[0077] The experimental steps for the application of alloy-modified nickel foam catalyst are as follows: Under nitrogen protection, 27.1 g of trichlorosilane and 3 g of alloy-modified nickel foam catalyst were added to a reaction flask and soaked for 30 min. The temperature was raised to 30℃ and stirred for 10 min. Then, 16.3 mL of 3-chloropropene was added dropwise to the reaction flask at a rate of 2 seconds / drop. After the addition was completed, the temperature was raised to 40℃ and stirred for 1 h to obtain the target product. The sample was taken with a syringe and the yield of 3-chloropropyltrichlorosilane was quantitatively analyzed by a GC-9790 gas chromatograph.

[0078] The gas chromatographic conditions and parameters for yield testing are as follows:

[0079] Configure an HP-5 chromatographic column (30m);

[0080] The detector temperature is set to 280℃;

[0081] The injection chamber temperature is set to 280℃;

[0082] The split ratio is set to 50:1;

[0083] The column flow rate was set to 1.0 mL / min;

[0084] The injection volume was set to 0.1 µL;

[0085] The yield test results of 3-chloropropyltrichlorosilane are shown in Table 2;

[0086] Table 2. Yield test results of 3-chloropropyltrichlorosilane

[0087] Product Categories Yield (%) of 3-chloropropyltrichlorosilane Alloy-modified nickel foam catalyst I 96.0 Alloy-modified foamed nickel catalyst II 92.8 Alloy-modified foamed nickel catalyst III 97.2 Comparative Example 1 (Foamed Nickel) 50.8 Comparative Example 2 (Commercial Karstedt catalyst) 82.1

[0088] Note: Comparative Example 1 uses nickel foam as a catalyst for the hydrosilylation reaction of trichlorosilane and 3-chloropropene. The mass of nickel foam added is the same as that of alloy-modified nickel foam catalyst I (3g).

[0089] Before using nickel foam as a catalyst, the following pretreatment is required: 4g of nickel foam with dimensions of 5cm×8cm×1cm (purchased from Jilin Newstar Metal Materials Co., Ltd., with a pore size of 90PPI and a bulk density of 0.1g / cm³) is applied. 3 (With a porosity of 98%), it was immersed in a 5wt% dilute hydrochloric acid solution and kept for 10 minutes to remove surface oxides and impurities. Then, it was immersed in a mixed solution of deionized water and anhydrous ethanol (volume ratio of deionized water and anhydrous ethanol was 1:1) and ultrasonically cleaned for 30 minutes. It was then vacuum dried at 50°C for 6 hours to obtain pretreated nickel foam.

[0090] Comparative Example 2 used a commercially available Karstedt catalyst as the catalyst for the hydrosilylation reaction of trichlorosilane and 3-chloropropene. When using it, the platinum content of the commercially available Karstedt catalyst was controlled to be the same as that of the alloy-modified nickel foam catalyst I (both were 31.6 mg / g × 3g = 94.8 mg).

[0091] The commercial Karstedt catalyst was purchased from Shanghai Silicon Power Advanced Materials Co., Ltd., with the product number ACS-Pt-20.

[0092] The following conclusions can be drawn from the analysis of the test results in Table 2:

[0093] Conclusion 1: The hydrosilylation reaction of trichlorosilane and 3-chloropropene to produce 3-chloropropyltrichlorosilane was catalyzed by alloy-modified nickel foam catalyst. Compared with unmodified nickel foam catalyst, the yield of 3-chloropropyltrichlorosilane product was increased to over 92%.

[0094] Conclusion 2: Compared with conventional commercial Karstedt catalysts with the same platinum content, the alloy-modified nickel foam catalyst exhibits significantly improved catalytic activity for hydrosilylation reactions.

[0095] Example 7:

[0096] Experiment 2: Application of alloy-modified nickel foam catalyst: The alloy-modified nickel foam catalyst was applied to the hydrosilylation reaction of polyether and hydrogen-containing silicone oil. The Si-H functional groups of the hydrogen-containing silicone oil and the alkenyl functional groups of polyethylene glycol monoallyl ether were catalyzed by the alloy-modified nickel foam catalyst to undergo an addition reaction, yielding polyether-modified silicone oil. The chemical reaction formula is as follows:

[0097] ;

[0098] The experimental steps for the application of alloy-modified nickel foam catalyst are as follows: Under nitrogen protection, 30g of hydrogen-containing silicone oil (hydrogen content of 0.1% and molecular weight of 2000g / mol) and 3g of alloy-modified nickel foam catalyst are added to a reaction flask, soaked for 30min, heated to 60℃ and stirred for 10min, then 10g of polyethylene glycol monoallyl ether (molecular weight of 400g / mol) is slowly added to the reaction flask, and the temperature is further raised to 100℃ and stirred for 4h to obtain polyether-modified silicone oil;

[0099] The Si-H content reacted with the polyether-modified silicone oil was tested by titration, and the Si-H conversion rate was obtained based on the Si-H content before and after the reaction. The specific test steps are as follows:

[0100] Take 1g of polyether-modified silicone oil product into an iodine flask, add 20mL of carbon tetrachloride and 10mL of 0.1mol / L bromo-acetic acid solution (prepared by dissolving elemental bromine in acetic acid solvent), cover with a ground glass stopper and shake well. React at room temperature for 120min in the dark. Then add 10mL of 0.1mol / L KI aqueous solution and continue to react at room temperature for 5min. After adding 50mL of deionized water, titrate with a standardized sodium thiosulfate solution (concentration of 0.1mol / L). Record the volume of sodium thiosulfate solution consumed at the reaction endpoint and calculate the silicon-hydrogen conversion rate. The specific calculation method is as follows:

[0101] Silicon-hydrogen conversion rate (%) = {N1 - [C(V1 - V2) / 2M]} / N2 × 100%;

[0102] Wherein, N1 is the total molar concentration of Si-H and alkenyl groups at the beginning of the reaction, and its unit is mol / g. At this time, N1={(10g / 400g / mol)+[(30g×0.1%) / 1g / mol]} / (30g+10g)=0.001375mol / g;

[0103] N2 is the initial mol / g concentration of Si-H. At this point, N2 = [(30g × 0.1%) / 1g / mol] / (30g + 10g) = 0.00075 mol / g.

[0104] C is the concentration of the sodium thiosulfate standard solution, and its unit is mol / L. At this time, C = 0.1 mol / L.

[0105] V1 is the volume of sodium thiosulfate standard solution consumed in the blank control group without polyether-modified silicone oil, in L.

[0106] V2 represents the volume of sodium thiosulfate standardization solution consumed by the polyether-modified silicone oil product, in liters (L).

[0107] M represents the amount of polyether-modified silicone oil product added, expressed in g. In this case, M = 1 g.

[0108] The test results of the hydroxyl conversion rate of polyether modified silicone oil are shown in Table 3.

[0109] Table 3. Test results of hydrogen silane conversion rate of polyether-modified silicone oil

[0110] Product Categories Hydrogen conversion rate of polyether modified silicone oil (%) Alloy-modified nickel foam catalyst I 94.6 Alloy-modified foamed nickel catalyst II 90.3 Alloy-modified foamed nickel catalyst III 96.7 Comparative Example 1 (Foamed Nickel) 36.2 Comparative Example 2 (Commercial Karstedt catalyst) 71.5

[0111] Note: Comparative Example 1 uses nickel foam as a catalyst for the hydrosilylation reaction of trichlorosilane and 3-chloropropene. The mass of nickel foam added is the same as that of alloy-modified nickel foam catalyst I (3g).

[0112] Before using nickel foam as a catalyst, the following pretreatment is required: 4g of nickel foam with dimensions of 5cm×8cm×1cm (purchased from Jilin Newstar Metal Materials Co., Ltd., with a pore size of 90PPI and a bulk density of 0.1g / cm³) is applied. 3 (With a porosity of 98%), it was immersed in a 5wt% dilute hydrochloric acid solution and kept for 10 minutes to remove surface oxides and impurities. Then, it was immersed in a mixed solution of deionized water and anhydrous ethanol (volume ratio of deionized water and anhydrous ethanol was 1:1) and ultrasonically cleaned for 30 minutes. It was then vacuum dried at 50°C for 6 hours to obtain pretreated nickel foam.

[0113] Comparative Example 2 used a commercially available Karstedt catalyst as the catalyst for the hydrosilylation reaction of trichlorosilane and 3-chloropropene. When using it, the platinum content of the commercially available Karstedt catalyst was controlled to be the same as that of the alloy-modified nickel foam catalyst I (both were 31.6 mg / g × 3g = 94.8 mg).

[0114] The commercial Karstedt catalyst was purchased from Shanghai Silicon Power Advanced Materials Co., Ltd., with the product number ACS-Pt-20.

[0115] By comprehensively analyzing the test results in Tables 2 and 3, the following conclusions can be drawn:

[0116] Conclusion 1: The hydrosilylation reaction between hydrogen-containing silicone oil and polyethylene glycol monoallyl ether was catalyzed by alloy-modified nickel foam catalyst to produce polyether-modified silicone oil. Compared with unmodified nickel foam, the hydrosilylation conversion rate of polyether-modified silicone oil was increased to over 90%.

[0117] Conclusion 2: The alloy-modified foamed nickel catalyst prepared in this invention exhibits excellent catalytic activity in the hydrosilylation reaction.

Claims

1. A method for the preparation of an alloy-modified foamed nickel catalyst, characterized in that, The method comprises the following steps: Step 1: synthesizing a ligand-type silane coupling agent with a chemical structural formula as follows: ； Step 2: based on a silicon hydroxyl-hydroxyl condensation reaction mechanism, grafting the ligand-type silane coupling agent on a foam nickel surface rich in hydroxyl functional groups to obtain a surface ligand modified foam nickel; Step 3: taking the ligand-type silane coupling agent grafted on the foam nickel surface and an imidazole monomer as a composite ligand, and assembling the composite ligand on the foam nickel surface through coordination with a nickel-platinum alloy and dissolved nickel ions to obtain an alloy modified foam nickel catalyst with the nickel-platinum alloy as a core.

2. The method of claim 1, wherein the alloy-modified foamed nickel catalyst is prepared by the steps of: The preparation method of the ligand-type silane coupling agent is as follows: through nucleophilic substitution reaction of 1 mole equivalent of -NH2 functional groups of melamine and 0.91-0.95 mole equivalent of bromine functional groups of a bromoalkenyl monomer, to generate an intermediate 1; through Schiff base condensation reaction of 1 mole equivalent of -NH2 functional groups of the intermediate 1 and 2.05-2.09 mole equivalent of aldehyde functional groups of 2-imidazole formaldehyde, to generate an intermediate 2; in the presence of a photoinitiator, through click reaction of 1 mole equivalent of alkenyl functional groups of the intermediate 2 and 1.01-1.05 mole equivalent of thiol functional groups of 3-mercaptopropyl trimethoxysilane under the action of ultraviolet light, to generate the ligand-type silane coupling agent.

3. The method of claim 2, wherein the alloy-modified foam nickel catalyst is prepared by the steps of: The bromoalkenyl monomer is one of 3-bromo-1-propene, 4-bromo-1-butene, 5-bromo-1-pentene, 6-bromo-1-hexene, 7-bromo-1-heptene and 8-bromo-1-octene.

4. The method of claim 2, wherein the alloy-modified foam nickel catalyst is prepared by the steps of: The photoinitiator is one of 2,2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropanone and 2,2-diethoxyacetophenone.

5. The method for preparing the alloy-modified nickel foam catalyst according to claim 3, characterized in that, When the bromoalkenyl monomer is 5-bromo-1-pentene, the chemical structural formula of the prepared ligand-type silane coupling agent is as follows: 。 6. The alloy-modified nickel foam catalyst prepared according to the method of any one of claims 1-5, characterized in that, The formula of the alloy modified foam nickel catalyst is: 4 parts by weight of foam nickel, 2 parts by weight of the ligand-type silane coupling agent, 8 parts by weight of the imidazole monomer and 0.5-1.5 parts by weight of the nickel-platinum alloy.

7. The alloy-modified foamed nickel catalyst of claim 6, wherein, The imidazole monomer is one of 2-methylimidazole, 2-ethyl-4-methylimidazole and 2-ethylimidazole.

8. The alloy-modified foamed nickel catalyst of claim 6, wherein, The particle size of the nickel-platinum alloy is 500-2000 mesh.

9. The alloy-modified foamed nickel catalyst of claim 6, wherein, The pore size of the foamed nickel is 80-100 PPI, the bulk density is 0.08-0.12 g / cm 3 , and the through-hole rate is 95-99%.

10. Use of the alloy-modified nickel foam catalyst prepared according to the method of any one of claims 1-5, characterized in that, The alloy modified foam nickel catalyst is used for catalyzing a silicon hydrogen addition reaction.

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