Preparation method of methacryloxysilane

Abstract

The invention discloses a preparation method of methylacryloyloxy silane, which comprises the following steps: adding allyl methacrylate into a solution containing trialkoxysilane, a platinum catalyst and a polymerization inhibitor, and reacting under a heating condition to obtain 3-(methylacryloyloxy) propyl trialkoxysilane; the platinum catalyst is compounded by platinum acetylacetonate and an accelerant; the accelerant is one or more of amine or phosphine organic reagents. According to the method, side reactions such as beta-addition are avoided, side reactions such as trialkoxysilane redistribution and product polymerization are limited, the selectivity and yield of the product are improved, the total chlorine content of the product is low, and the dosage of the catalyst is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of organic silicon, and in particular to a method for preparing methacryloxysilane. Background Art

[0002] Methacryloxysilane is a widely used organic silane coupling agent, mainly used in unsaturated polyester composite materials, which can improve the mechanical properties, electrical properties, and light transmittance of composite materials, especially can greatly improve the wet performance of composite materials; used as a wetting agent to treat glass fiber, it can improve the strength of glass fiber products, improve the mechanical strength and electrical properties of the products in the wet state; used to treat filler-filled oxide-crosslinked EPM and EPDM systems, it can improve the dissipation factor and specific inductance and capacitance, and at the same time improve the weather resistance of wires and cables.

[0003] The mainstream industrial production method of 3-(methacryloyloxy)propyltrialkoxysilane is to use the nucleophilic substitution reaction of sodium methacrylate and 3-chloropropyltrialkoxysilane. However, the reaction needs to be carried out at 130℃~160℃, and the product is prone to free radical polymerization at this temperature, which reduces the product yield; and NaCl is generated during the reaction (US2002 / 0115878 Al), and solvents such as DMF need to be added to improve the mixing efficiency. In the post-processing process, an additional solvent recovery step is required, and the production energy consumption is high; the reactant 3-chloropropyltrialkoxysilane has a close boiling point to the product, and the total chlorine content of the product after distillation is high.

[0004] The synthesis method of hydrosilylation of trialkoxysilane and allyl methacrylate (AMA) was first reported by Knorre et al. in 1968 (DE 1271712). Subsequently, the UCC research team in the United States used chloroplatinic acid as a catalyst (US4709067) to synthesize 3-(methacryloyloxy)propyl trialkoxysilane by hydrosilylation reaction, and achieved industrial production. However, the process temperature of the chloroplatinic acid catalyst is difficult to control, the initial reaction temperature is low, and it is difficult to induce the hydrosilylation reaction. Chloroplatinic acid causes the raw material trialkoxysilane to undergo a redistribution side reaction, and the reaction yield is reduced; when the initial reaction temperature is increased and the addition reaction is initiated, the temperature of the reaction system will rise rapidly, resulting in the occurrence of a β-addition side reaction, which increases the difficulty of product purification, thereby affecting the water solubility and bonding properties of the product, and also inducing a series of side reactions such as product polymerization, and the product yield is reduced (CN 110229181A, CN 101648967A), which limits the application of this synthesis method in industrial production.

[0005] Summary of the invention

[0006] In order to solve the above defects in the prior art, the present invention provides a method for preparing methacryloxysilane, which avoids the occurrence of side reactions such as β-addition and has the advantages of high selectivity, high yield, high efficiency, etc.

[0007] To achieve the above-mentioned object of the invention, the first aspect of the present invention provides a method for preparing methacryloxysilane, comprising the following steps:

[0008] Allyl methacrylate (AMA) is added to a solution containing trialkoxysilane, a platinum catalyst and an inhibitor, and reacted under heating conditions to obtain 3-(methacryloyloxy)propyltrialkoxysilane; the platinum catalyst is formed by the coordination of platinum acetylacetonate and a promoter; the promoter is one or more of an amine or phosphine organic reagent.

[0009] The platinum catalyst of the present invention adopts platinum acetylacetonate, has a moderate initiation temperature, and the temperature rise after the initiation reaction is not obvious, and can effectively inhibit side reactions such as polymerization.

[0010] In some specific embodiments, the promoter is one or more of tetramethylethylenediamine, triethylamine, and triphenylphosphine, preferably tetramethylethylenediamine.

[0011] In some specific embodiments, the amount of platinum catalyst added is calculated based on the amount of Pt, and the mass ratio of platinum catalyst to trialkoxysilane is 5 to 10 ppm, exemplified by 5 ppm, 6 ppm, 7 ppm, 8 ppm, 9 ppm, 10 ppm, etc., which is less than the amount of catalyst used in the prior art.

[0012] In some specific embodiments, the platinum catalyst used is obtained by the following method: dissolving platinum acetylacetonate in a solvent and mixing with a promoter, and reacting under reflux conditions for 1 to 2 hours to obtain a platinum catalyst. For example, the reaction is carried out at a temperature of 56° C. and normal pressure.

[0013] In some specific embodiments, the molar ratio of the promoter to platinum acetylacetonate is 3 to 5:1, illustratively 3:1, 4:1, 5:1, etc.

[0014] In some specific embodiments, the polymerization inhibitor is one or more of 2,6-di-tert-butylphenol, phenothiazine or N,N-diphenyl-p-phenylenediamine, and the amount of the polymerization inhibitor added is 1-3 wt % of the trialkoxysilane mass. Adding the polymerization inhibitor can limit the occurrence of polymerization side reactions.

[0015] In some specific embodiments, the trialkoxysilane is trimethoxysilane or triethoxysilane; the molar ratio of the trialkoxysilane to AMA is 1:(0.95-1), preferably 1:(0.98-1).

[0016] In some specific embodiments, the temperature of the reaction under heating conditions is 90-125°C, exemplified by 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, etc. The above reaction temperature of the present invention is lower than the reaction temperature of the mainstream method for synthesizing KH570, which can limit the occurrence of polymerization side reactions and has low energy consumption.

[0017] In some specific embodiments, the preparation method of methacryloxysilane comprises the following steps: heating trialkoxysilane to 90-95°C, adding a platinum catalyst and an inhibitor, starting to drip AMA, controlling the temperature at 90-125°C during the dripping process, maintaining the temperature at 90-125°C for 1-3 hours after the dripping is completed, and then distilling to obtain the product 3-(methacryloyloxy)propyltrialkoxysilane.

[0018] In some specific embodiments, the distillation is a reduced pressure distillation.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] Different from the prior art, the present invention adopts a catalyst system of acetylacetonate platinum and a promoter, and uniformly adds AMA to a solution containing trialkoxysilane, a platinum catalyst, and a polymerization inhibitor, and reacts under heating conditions to obtain 3-(methacryloyloxy)propyltrialkoxysilane. The reaction formula is as follows:

[0021]

[0022] The preparation method of the present invention obtains 3-(methacryloyloxy)propyltrialkoxysilane products, wherein the ratio of α-addition products to β-addition products is 99%:1% to 99.9%:0.1%, and the total chlorine content is less than 30 ppm. The occurrence of side reactions such as β-addition is avoided, side reactions such as trialkoxysilane redistribution and product polymerization are restricted, and the selectivity and yield of the product are improved.

[0023] Other features and advantages of the present invention will be described in detail through the following detailed description. DETAILED DESCRIPTION

[0024] The following will clearly and completely describe the concept of the present application and the technical effects produced in combination with the embodiments, so as to fully understand the purpose, features and effects of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of them. Based on the embodiments of the present application, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present application.

[0025] raw material:

[0026] Trimethoxysilane, INNOCHEM, 98%;

[0027] Triethoxysilane, INNOCHEM, 99%;

[0028] Allyl methacrylate, INNOCHEM, 99%;

[0029] Tetramethylethylenediamine, INNOCHEM, 99%;

[0030] 2,6-di-tert-butylphenol, INNOCHEM, 99%;

[0031] Phenothiazine, INNOCHEM, 99%;

[0032] N,N-diphenyl-p-phenylenediamine, INNOCHEM, 99%;

[0033] Gas chromatography instrument: Agilent 8890. Test method: Initial temperature 40°C, hold for 6 minutes; increase temperature 5°C / min to 80°C, hold for 0 minutes; increase temperature 30°C / min to 300°C, hold for 0 minutes.

[0034] NMR analysis instrument: Bruker AVANCE 400MHz

[0035] Preparation of platinum catalyst:

[0036] 1 g of platinum acetylacetonate was dissolved in 97.82 g of acetone, and then 1.18 g of tetramethylethylenediamine was added, followed by reflux reaction for 1 hour (reaction temperature 56° C., pressure normal pressure), and after cooling, a liquid Pt catalyst was obtained, which was recorded as A1.

[0037] 1 g of platinum acetylacetonate was added to 97.82 g of acetone to dissolve, and then 2.66 g of triphenylphosphine was added, followed by reflux reaction for 1 hour (reaction temperature 56° C., pressure normal pressure), and after cooling, a liquid Pt catalyst was obtained, which was recorded as A2.

[0038] Example 1

[0039] Add trimethoxysilane (1kg) to the reactor under nitrogen protection, stir and heat to 90°C, add 2,6-di-tert-butylphenol (29g), 0.5wt% Pt catalyst (A1) 1.27mL, add AMA (1003g) to the reactor at a rate of 4.8g / min, and the maximum temperature of the reaction system reaches 103°C. After the addition of AMA is completed, keep warm and stir at 95°C for 1.5 hours to obtain a crude product. The crude product is distilled under reduced pressure to collect 1852g of a colorless transparent liquid product at 118-120°C (1mmHg). The purity of gas chromatography analysis is 98%, the yield is 93%, the ratio of α-addition product to β-addition product is 99.5%:0.5%, and the total chlorine content is 23ppm. Structural information of α-addition product, 13 C-NMR chemical shift (100 MHz, CDCl 3 ): 5.3(-CH 2 -Si-O-),18.3(CH 3 -CH-),22.2(CH 2 -(CH 2 ) 2 -),50.6(CH 3 -O-Si),66.0(CH 2 -O),125.0(CH 2 -C=O), 136.7(C-CH 2 ),167.0(C=O). β-addition product structure information, 13 C-NMR chemical shift (100 MHz, CDCl 3 ): 3.9 (CH 3 -CH-Si-),18.3(CH 3 -CH-), 21.9(CH-Si-O-), 50.6(CH 3 -O-Si),66.0(CH 2 -O),125.0(CH 2 -C=O), 136.7(C-CH 2 ),167.0(C=O).

[0040] Example 2

[0041] Add trimethoxysilane (1kg) to the reactor under nitrogen protection, stir and heat to 90°C, add 2,6-di-tert-butylphenol (29g), 0.5wt% Pt catalyst (A2) 1.27mL, add AMA (1003g) to the reactor at a speed of 4.8g / min, and the maximum temperature of the reaction system reaches 100°C. After the addition of AMA is completed, keep warm and stir at 95°C for 1.5 hours to obtain a crude product. The crude product is subjected to reduced pressure distillation, and 1792g of a colorless transparent liquid product at 118-120°C (1mmHg) is collected. The purity of gas chromatography analysis is 98%, the yield is 90%, the ratio of α-addition product to β-addition product is 99%:1%, and the total chlorine content is 17ppm.

[0042] Example 3

[0043] Under nitrogen protection, trimethoxysilane (1kg) was added to the reactor, stirred and heated to 90°C, phenothiazine (29g) and 0.5wt% Pt catalyst (A1) 1.27mL were added, AMA (1003g) was added to the reactor at a rate of 4.8g / min, and the maximum temperature of the reaction system reached 103°C. After the addition of AMA was completed, the crude product was obtained after being kept warm and stirred at 95°C for 1.5 hours. The crude product was subjected to reduced pressure distillation, and about 1732g of a colorless transparent liquid product at 118-120°C (1mmHg) was collected. The purity of gas chromatography analysis reached 98%, the yield was 87%, the ratio of α-addition product to β-addition product was 99.5%:0.5%, and the total chlorine content was 25ppm.

[0044] Example 4

[0045] Add trimethoxysilane (1kg) to the reactor under nitrogen protection, stir and heat to 90°C, add N,N-diphenyl-p-phenylenediamine (29g), 0.5wt% Pt catalyst (A1) 1.27mL, add AMA (1003g) to the reactor at a rate of 4.8g / min, and the maximum temperature of the reaction system reaches 103°C. After the addition of AMA is completed, keep warm and stir at 95°C for 1.5 hours to obtain a crude product. The crude product is subjected to reduced pressure distillation, and about 1812g of a colorless transparent liquid product at 118-120°C (1mmHg) is collected. The purity of gas chromatography analysis is 98%, the yield is 91%, the ratio of α-addition product to β-addition product is 99.3%:0.7%, and the total chlorine content is 21ppm.

[0046] Example 5

[0047] Add triethoxysilane (1kg) to the reactor under nitrogen protection, stir and heat to 90°C, add 2,6-di-tert-butylphenol (29g), 0.5wt% Pt catalyst (A1) 1.27mL, add AMA (768g) to the reactor at a rate of 4.8g / min, and the maximum temperature of the reaction system reaches 105°C. After the addition of AMA is completed, keep warm and stir at 95°C for 1.5 hours to obtain a crude product. The crude product is subjected to reduced pressure distillation, and about 1646g of a colorless transparent liquid product at 125-132°C (1mmHg) is collected. The purity of gas chromatography analysis is 98%, the yield is 94%, the ratio of α-addition product to β-addition product is 99.5%:0.5%, and the total chlorine content is 15ppm.

[0048] Example 6

[0049] Add trimethoxysilane (1kg) to the reactor under nitrogen protection, stir and heat to 105°C, add 2,6-di-tert-butylphenol (29g), 0.5wt% Pt catalyst (A1) 1.27mL, add AMA (1003g) to the reactor at a rate of 4.8g / min, and the maximum temperature of the reaction system reaches 122°C. After the addition of AMA is completed, keep warm and stir at 95°C for 1.5 hours to obtain a crude product. The crude product is subjected to reduced pressure distillation, and 1712g of a colorless transparent liquid product at 118-120°C (1mmHg) is collected. The purity of gas chromatography analysis is 98%, the yield is 86%, the ratio of α-addition product to β-addition product is 99%:1%, and the total chlorine content is 19ppm.

[0050] Example 7

[0051] Add trimethoxysilane (1kg) to the reactor under nitrogen protection, stir and heat to 125°C, add 2,6-di-tert-butylphenol (29g), 0.5wt% Pt catalyst (A1) 1.27mL, add AMA (1003g) to the reactor at a speed of 4.8g / min, and the maximum temperature of the reaction system reaches 143°C. After the addition of AMA is completed, keep warm and stir at 95°C for 1.5 hours to obtain a crude product. The crude product is subjected to reduced pressure distillation, and 1294g of a colorless transparent liquid product at 118-120°C (1mmHg) is collected. The purity of gas chromatography analysis is 98%, the yield is 65%, the ratio of α-addition product to β-addition product is 97%:3%, and the total chlorine content is 34ppm.

[0052] Example 8

[0053] Add trimethoxysilane (1kg) to the reactor under nitrogen protection, stir and heat to 90°C, add 2,6-di-tert-butylphenol (29g), 0.5wt% Pt catalyst (A1) 2.04mL, add AMA (1003g) to the reactor at a speed of 4.8g / min, and the maximum temperature of the reaction system reaches 110°C. After the addition of AMA is completed, keep warm and stir at 95°C for 1.5 hours to obtain a crude product. The crude product is subjected to reduced pressure distillation, and 1812g of a colorless transparent liquid product at 118-120°C (1mmHg) is collected. The purity of gas chromatography analysis is 98%, the yield is 91%, the ratio of α-addition product to β-addition product is 99.5%:0.5%, and the total chlorine content is 27ppm.

[0054] Example 9

[0055] Add trimethoxysilane (1kg) to the reactor under nitrogen protection, stir and heat to 90°C, add 2,6-di-tert-butylphenol (29g), 0.5wt% Pt catalyst (A1) 2.58mL, add AMA (1003g) to the reactor at a speed of 4.8g / min, and the maximum temperature of the reaction system reaches 110°C. After the addition of AMA is completed, keep warm and stir at 95°C for 1.5 hours to obtain a crude product. The crude product is subjected to reduced pressure distillation, and 1832g of a colorless transparent liquid product at 118-120°C (1mmHg) is collected. The purity of gas chromatography analysis is 98%, the yield is 92%, the ratio of α-addition product to β-addition product is 99.5%:0.5%, and the total chlorine content is 24ppm.

[0056] Comparative Example 1

[0057] Add trimethoxysilane (1kg) to the reactor under nitrogen protection, stir and heat to 90°C, add 2,6-di-tert-butylphenol (29g), 1.27mL of 0.5wt% isopropanol solution of chloroplatinic acid, add AMA (1003g) to the reactor at a speed of 4.8g / min, and the maximum temperature of the reaction system reaches 133°C. After the addition of AMA is completed, stir at 95°C for 1.5 hours to obtain a crude product. The crude product is subjected to reduced pressure distillation, and 1613g of a colorless transparent liquid product at 118-120°C (1mmHg) is collected. The purity of gas chromatography analysis is 98%, the yield is 81%, the ratio of α-addition product to β-addition product is 94%:6%, and the total chlorine content is 23ppm.

[0058] Comparative Example 2

[0059] Add trimethoxysilane (1kg) to the reactor under nitrogen protection, stir and heat to 90°C, add 2,6-di-tert-butylphenol (29g), 1.27mL of 0.5wt% isopropanol solution of chloroplatinic acid, add AMA (1003g) to the reactor at a speed of 2g / min, and the maximum temperature of the reaction system reaches 110°C. After the addition of AMA is completed, keep warm and stir at 95°C for 1.5 hours to obtain a crude product. The crude product is subjected to reduced pressure distillation, and 1693g of a colorless transparent liquid product at 118-120°C (1mmHg) is collected. The purity of gas chromatography analysis is 98%, the yield is 85%, the ratio of α-addition product to β-addition product is 95%:5%, and the total chlorine content is 27ppm.

[0060] Comparative Examples 1-2 use an isopropanol solution of chloroplatinic acid. Compared with the embodiments of the present invention, the proportion of β-addition products obtained in the comparative examples is significantly increased, and the yield is reduced; after analysis, it is believed that the period of chloroplatinic acid catalyst in initiating the hydrosilylation reaction in such reactions is relatively long. Under the condition of 90°C, chloroplatinic acid will cause the raw material trialkoxysilane to undergo a redistribution side reaction, and the reaction yield is reduced; after initiating the addition reaction, due to the large accumulation of the reactant AMA, the temperature of the reaction system will rise rapidly, resulting in the occurrence of redistribution side reactions and polymerization reactions, and the product yield is reduced. Even if the addition rate of AMA is reduced and the accumulation amount of AMA is reduced, the proportion of β-addition products in the product is still very high due to the lack of the spatial effect of the large sterically hindered ligand, which increases the difficulty of product purification and thus affects the application performance of the product.

[0061] In summary, the present invention uses a catalytic system of platinum acetylacetonate and a promoter to uniformly add allyl methacrylate (AMA) to a solution containing trialkoxysilane, a platinum catalyst and an inhibitor, and obtains 3-(methacryloyloxy)propyltrialkoxysilane with high selectivity, high efficiency and high yield under heating conditions, thereby avoiding the occurrence of side reactions such as β-addition, improving the product yield and quality, and having prospects for industrial production.

[0062] Obviously, the above embodiments of the present invention are merely examples for clearly explaining the present invention, and are not intended to limit the implementation methods of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is impossible to list all implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are within the spirit scope of the present invention.

Claims

1. A method for preparing methacryloxysilane, characterized in that: The steps include: Allyl methacrylate is added to a solution containing trialkoxysilane, a platinum catalyst and an inhibitor, and reacted under heating conditions to obtain 3-(methacryloyloxy)propyltrialkoxysilane; the platinum catalyst is prepared by complexing platinum acetylacetonate with a promoter; the promoter is one or more amine or phosphine organic reagents.

2. The method for preparing methacryloxysilane according to claim 1, characterized in that: The accelerator is one or more of tetramethylethylenediamine, triethylamine, and triphenylphosphine, preferably tetramethylethylenediamine.

3. The method for preparing methacryloxysilane according to claim 1, characterized in that: The amount of platinum catalyst added is calculated based on the amount of Pt, and the mass ratio of the platinum catalyst to trialkoxysilane is 5 to 10 ppm.

4. The method for preparing methacryloxysilane according to any one of claims 1 to 3, characterized in that: The platinum catalyst is obtained by the following method: dissolving platinum acetylacetonate in a solvent and mixing with a promoter, and reacting for 1 to 2 hours under reflux conditions to obtain the platinum catalyst.

5. The method for preparing methacryloxysilane according to any one of claims 1 to 4, characterized in that: The molar ratio of the accelerator to platinum acetylacetonate is 3 to 5:

1.

6. The method for preparing methacryloxysilane according to claim 1, characterized in that: The polymerization inhibitor is one or more of 2,6-di-tert-butylphenol, phenothiazine or N,N-diphenyl-p-phenylenediamine, and the amount of the polymerization inhibitor added is 1-3 wt % of the trialkoxysilane mass.

7. The method for preparing methacryloxysilane according to any one of claims 1 to 6, characterized in that: The trialkoxysilane is trimethoxysilane or triethoxysilane; the molar ratio of the trialkoxysilane to allyl methacrylate is 1:(0.95-1), preferably 1:(0.98-1).

8. The method for preparing methacryloxysilane according to any one of claims 1 to 7, characterized in that: The temperature of the reaction under heating conditions is 90-125°C.

9. The method for preparing methacryloxysilane according to any one of claims 1 to 8, characterized in that: The preparation method of methacryloxysilane comprises the following steps: heating trialkoxysilane to 90-95°C, adding a platinum catalyst and a polymerization inhibitor, starting to drop allyl methacrylate, controlling the temperature at 90-125°C during the dropping process, maintaining the temperature at 90-125°C for reaction for 1-3 hours after the dropping is completed, and then distilling to obtain the product 3-(methacryloyloxy)propyltrialkoxysilane.

10. The method for preparing methacryloxysilane according to claim 9, characterized in that: The distillation is a reduced pressure distillation.

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