Synthesis method of N-methyl-N-(2-diethylaminoethyl)-3-aminopropyltrimethoxysilane

Abstract

The invention discloses a method for synthesizing N-methyl-N-(2-diethylaminoethyl)-3-aminopropyltrimethoxysilane, and relates to the technical field of chemical synthesis. Chloroethyldimethylamine and N-methyl-3-aminopropyltrimethoxysilane are reacted in an organic alkaline solvent and then filtered to obtain a filter cake. The filtrate after washing the filter cake is distilled to obtain N-methyl-N-(2-diethylaminoethyl)-3-aminopropyltrimethoxysilane. Compared with the prior art, the present invention has high yield, controllable process, easy to obtain raw materials, low cost, easy operation in the production process, suitable for industrial production, economical and highly safe.

Description

Technical Field

[0001] The invention relates to the technical field of chemical synthesis. Background Art

[0002] The organosilanes most commonly used in surface modification are silicon chemicals with a single hydrolysis-sensitive center that reacts with inorganic substrates such as glass to form a stable covalent oxyalkyl bond. These organosilanes also have organic substituents whose function is to alter the physical interaction of the modified surface with various substrates. The most widely used silanes modify inorganic substrates such as glass fibers to form bonds with organic materials such as polymers to form reinforced composites, and these silanes are often referred to as coupling agents.

[0003] As is well known in the art, aminopropyl alkoxysilane compounds are widely used as silane coupling agents and can be modified in various ways, such as improving adhesion at organic-inorganic interfaces, customizing various resins, and modifying surfaces.

[0004] At present, the main preparation process for this type of compound at home and abroad is to use 3-chloropropyltrimethoxysilane and the corresponding excess amine to react to obtain the product. The principle is as follows:

[0005]

[0006] In the synthesis method of the compound of the above method, since the raw material N,N,N'-trimethylethylenediamine has a relatively low market price of industrial products and a relatively high price, the production cost of the process is relatively high, which is not conducive to industrial production. Summary of the invention

[0007] In order to overcome the above-mentioned deficiencies of the prior art, the present invention provides a method for synthesizing N-methyl-N-(2-diethylaminoethyl)-3-aminopropyltrimethoxysilane.

[0008] The technical scheme of the present invention is: chloroethyldimethylamine and N-methyl-3-aminopropyltrimethoxysilane are reacted in an organic alkali solvent, and then filtered to obtain a filter cake; the filtrate after washing the filter cake is distilled to obtain N-methyl-N-(2-diethylaminoethyl)-3-aminopropyltrimethoxysilane.

[0009] Reaction formula of the present invention is as follows:

[0010]

[0011] The reaction is that chloroethyldimethylamine and N-methyl-3-aminopropyltrimethoxysilane use an organic base (triethylamine, pyridine, N,N-dimethylaniline) as an acid-binding agent to remove hydrogen chloride and simultaneously generate a new tertiary amino compound N-methyl-N-(2-diethylaminoethyl)-3-aminopropyltrimethoxysilane.

[0012] Compared with the prior art, the present invention has high yield, controllable process, readily available raw materials, low cost, easy operation during the production process, is suitable for industrial production, and is economical and highly safe.

[0013] Furthermore, the organic base is any one of triethylamine, pyridine and N,N-dimethylaniline as an acid-binding agent, which is also a solvent; triethylamine is preferred. Compared with other organic bases, triethylamine is more suitable for the reaction due to its alkalinity and solvent effect, which is beneficial to improving the yield and recycling.

[0014] Furthermore, the reaction temperature is 65-100° C., preferably 80-100° C. This temperature is conducive to the rapid generation of products and can inhibit the occurrence of side reactions.

[0015] Furthermore, the molar ratio of chloroethyldimethylamine to N-methyl-3-aminopropyltrimethoxysilane is 0.98:1-1.1. Repeated experiments have shown that the reaction is beneficial to the formation of products in an organic base environment when the N-methyl-3-aminopropyltrimethoxysilane is in equal amounts or in excess.

[0016] Furthermore, washing the filter cake with an organic base (triethylamine, pyridine, N,N-dimethylaniline) can prevent the introduction of other organic solvents during washing, and using a single solvent is conducive to the recovery and reuse of the solvent.

[0017] Repeated research and experiments have shown that under the same reaction conditions, when triethylamine is used as a solvent and acid-binding agent, the product yield is significantly higher than that of other organic amines, and triethylamine is easy to recycle and reuse. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The following are the H-NMR spectra of the products obtained in Examples 1 to 5, respectively. DETAILED DESCRIPTION

[0019] 1. Preparation process:

[0020] Embodiment 1:

[0021] In a 1000mL four-necked bottle with mechanical stirring, add 190g of N-methyl-3-aminopropyltrimethoxysilane and 400g of triethylamine. Turn on the stirrer and heat the reaction system to 65-75°C. Then slowly add 160g of chloroethyldimethylamine at a rate of 40-55mL / min. The mixture will be added in about 3-4h.

[0022] The reason for slowly adding chloroethyldimethylamine at a rate of 40 to 55 mL / min is that adding it too quickly will result in an excessively high concentration of chloroethyldimethylamine, causing side reactions.

[0023] The reaction system temperature was maintained at 65-75°C for 12 hours, and then samples were taken for gas chromatography analysis until the chloroethyldimethylamine was completely reacted. The temperature was then cooled to below 40°C in a water bath and then filtered.

[0024] Take the filter cake (the main components are triethylamine hydrochloride, triethylamine, some adsorption products and triethylamine) and stir and wash it twice with 100g of triethylamine (most of the product will be dissolved in triethylamine), and combine the filtrates.

[0025] The filtrate was placed in a 50 cm distillation tower and distilled under reduced pressure to obtain 317 g of product with a yield of 80%.

[0026] Embodiment 2:

[0027] In a 1000ml four-necked bottle with mechanical stirring, add 190g of N-methyl-3-aminopropyltrimethoxysilane and 400g of triethylamine. After the system is heated to 80-100°C, 160g of chloroethyldimethylamine is slowly added dropwise at a rate of 40-55mL / min. The addition takes about 3-4h.

[0028] The reaction system temperature was maintained at 65-75°C for 12 hours, and then a sample was taken for gas chromatography analysis until the chloroethyldimethylamine was completely reacted. The temperature was then cooled to below 40°C in a water bath, and then filtered, and the filter cake was taken and washed twice with 100g of triethylamine respectively.

[0029] The filtrates were combined and placed in a 50 cm distillation tower for vacuum distillation to obtain 337 g of product with a yield of 85%.

[0030] Embodiment 3:

[0031] In a 1000ml four-necked bottle with mechanical stirring, add 209g of N-methyl-3-aminopropyltrimethoxysilane and 400g of N,N-dimethylaniline. After the system is heated to 65-75°C, 160g of chloroethyldimethylamine is slowly added dropwise at a rate of 40-55mL / min. The addition takes about 3-4h.

[0032] The reaction system temperature was maintained at 65-75°C for 12 hours, and then samples were taken for gas chromatography analysis until the chloroethyldimethylamine was completely reacted. The temperature was then cooled to below 40°C in a water bath and then filtered.

[0033] The filter cake was washed twice with 100 g of N,N-dimethylaniline respectively.

[0034] The filtrates were combined and placed in a 50 cm distillation tower for vacuum distillation to obtain 344 g of product with a yield of 87%.

[0035] Embodiment 4:

[0036] In a 1000ml four-necked bottle with mechanical stirring, add 209g of N-methyl-3-aminopropyltrimethoxysilane and 400g of triethylamine, heat the system to 80-100°C, and then slowly add 160g of chloroethyldimethylamine at a rate of 40-55mL / min. The mixture will be added in about 3-4h.

[0037] The temperature of the reaction system was maintained at 80-100°C for 12 hours, and then a sample was taken for gas chromatography analysis until the reaction of chloroethyldimethylamine was complete. The temperature was then lowered to below 40°C in a water bath and then filtered.

[0038] The filter cake was washed twice with 100 g of triethylamine respectively.

[0039] The filtrates were combined and placed in a 50 cm distillation tower for vacuum distillation to obtain 368 g of product with a yield of 93%.

[0040] Embodiment 5:

[0041] In a 1000ml four-necked bottle with mechanical stirring, add 209g of N-methyl-3-aminopropyltrimethoxysilane and 400g of pyridine. After the system is heated to 80-100°C, 160g of chloroethyldimethylamine is slowly added dropwise at a rate of 40-55mL / min. The addition takes about 3-4h.

[0042] The temperature of the reaction system was maintained at 80-100°C for 12 hours, and then a sample was taken for gas chromatography analysis until the reaction of chloroethyldimethylamine was complete. The temperature was then lowered to below 40°C in a water bath and then filtered.

[0043] The filter cake was washed twice with 100 g of pyridine respectively.

[0044] The filtrates were combined and placed in a 50 cm distillation tower for vacuum distillation to obtain 360 g of product with a yield of 91%.

[0045] 2. Perform nuclear magnetic hydrogen spectrum analysis on the products obtained in the above examples:

[0046] Depend on Figure 1 It can be seen from the H-NMR spectrum analysis that the products in the above embodiments are the target product N-methyl-N-(2-diethylaminoethyl)-3-aminopropyltrimethoxysilane.

[0047] It can be seen from the above embodiments that the present invention can react under the conditions of a molar ratio of chloroethyldimethylamine to N-methyl-3-aminopropyltrimethoxysilane of 0.98:1-1.1, a temperature of 65-100°C, and an organic base (triethylamine, pyridine, N,N-dimethylaniline); wherein the molar ratio of chloroethyldimethylamine to N-methyl-3-aminopropyltrimethoxysilane is 0.98:1.1, the temperature is 80-100°C, and the organic base is triethylamine.

Claims

1. A method for synthesizing N-methyl-N-(2-diethylaminoethyl)-3-aminopropyltrimethoxysilane, characterized in that: In a 1000ml four-necked bottle with mechanical stirring, add 209g of N-methyl-3-aminopropyltrimethoxysilane and 400g of triethylamine, raise the temperature of the system to 80-100°C, and then slowly add 160g of chloroethyldimethylamine at a rate of 40-55mL / min for 3-4h; The temperature of the reaction system was maintained at 80-100°C for 12 hours, and then a sample was taken for gas chromatography analysis until the reaction of chloroethyldimethylamine was complete, and then the temperature was lowered to below 40°C in a water bath and then filtered; The filter cake was washed twice with 100 g of triethylamine by stirring; The filtrates were combined and placed in a 50 cm distillation tower for vacuum distillation to obtain 368 g of N-methyl-N-(2-diethylaminoethyl)-3-aminopropyltrimethoxysilane product.

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