阅读说明：本技术 一种双(n-甲基苯甲酰胺)乙氧基甲基硅烷的制备方法 (Preparation method of bis (N-methylbenzamide) ethoxymethylsilane ) 是由 王伟 李冲合 徐建清 陈嘉华 金涵 于 2021-09-23 设计创作，主要内容包括：本发明涉及硅烷交联剂技术领域,为了克服现有双(N-甲基苯甲酰胺)乙氧基甲基硅烷制备方法副产物多、产率低、不易分离提纯、生产耗能较高的不足,提供一种双(N-甲基苯甲酰胺)乙氧基甲基硅烷的制备方法。通过使用甲基二氯氢硅作为起始原料,先后与N-甲基苯甲酰胺、乙醇一锅法反应得到双(N-甲基苯甲酰胺)乙氧基甲基硅烷,得到的双(N-甲基苯甲酰胺)乙氧基甲基硅烷纯度高、产率高、易分离纯化,且生产耗能少,得到的铵盐还可回收利用,产生的三废少,原子利用率高。(The invention relates to the technical field of silane cross-linking agents, and provides a preparation method of bis (N-methylbenzamide) ethoxy methylsilane in order to overcome the defects of the existing preparation method of bis (N-methylbenzamide) ethoxy methylsilane, such as more byproducts, low yield, difficulty in separation and purification, and high production energy consumption. The method comprises the steps of using methyl dichlorosilane as a starting raw material, reacting with N-methylbenzamide and ethanol in sequence in a one-pot method to obtain bis (N-methylbenzamide) ethoxymethylsilane, wherein the obtained bis (N-methylbenzamide) ethoxymethylsilane is high in purity, high in yield, easy to separate and purify, low in production energy consumption, recyclable in obtained ammonium salt, less in three wastes and high in atom utilization rate.)

1. A preparation method of bis (N-methylbenzamide) ethoxymethylsilane is characterized by comprising the following steps:

A. dripping N-methylbenzamide into a methyl dichlorosilane solution, heating, adding an acid-binding agent, and reacting to obtain an intermediate product, namely bis (N-methylbenzamide) methyl hydrosilane;

B. and D, adding a catalyst and ethanol into the intermediate product system in the step A to continue reacting, and separating to obtain the bis (N-methylbenzamide) ethoxymethylsilane.

2. The preparation method of bis (N-methylbenzamide) ethoxymethylsilane according to claim 1, wherein in the step A, the molar ratio of N-methylbenzamide to methyl dichlorosilane is 2.1-2.3: 1.

3. The method for preparing bis (N-methylbenzamide) ethoxymethylsilane according to claim 1, wherein in the step A, the solvent of the methyl dichlorosilane solution is at least one of toluene, xylene and petroleum ether; the acid-binding agent is ammonia.

4. The preparation method of bis (N-methylbenzamide) ethoxymethylsilane according to claim 1 or 3, wherein in the step A, the molar ratio of ammonia to methyl dichlorosilane is 2-2.4: 1.

5. The method for preparing bis (N-methylbenzamide) ethoxymethylsilane according to claim 1, wherein in the step A, the reaction temperature is 60 to 120 ℃ and the reaction time is 1 to 3 hours.

6. The method for preparing bis (N-methylbenzamide) ethoxymethylsilane according to claim 1, wherein in the step B, the catalyst is a metal or molecular sieve catalyst with dehydrogenation, the active component comprises at least one of nickel nitrate, nickel sulfate and nickel chloride, and the molar ratio of the catalyst to the methyl dichlorosilane is 0.005-0.1%.

7. The preparation method of bis (N-methylbenzamide) ethoxymethylsilane according to claim 1, wherein in the step B, the molar ratio of ethanol to methyl dichlorosilane is 0.95-1.05: 1.

8. The method for preparing bis (N-methylbenzamide) ethoxymethylsilane according to claim 1, wherein in the step B, the reaction temperature is 50 to 80 ℃ and the reaction time is 3 to 5 hours.

Technical Field

The invention relates to the technical field of silane cross-linking agents, in particular to a preparation method of bis (N-methylbenzamide) ethoxymethylsilane.

Background

The room temperature vulcanized silicone rubber is a high-tech material, and the most obvious characteristic of the rubber is that the rubber can be cured in situ without heating at room temperature, and the use is very convenient. Therefore, the silicone rubber quickly becomes an important component of the whole organic silicon product once coming out, is widely applied to various industries such as buildings, decorations, automobiles, electronics, solar energy and the like, and continuously develops new application of the silicone rubber. There are several systems for room temperature vulcanized silicone rubber. The common ketoxime removal system with ketoxime silane as a cross-linking agent, the acid removal system with acyloxy silane as a cross-linking agent, the dealcoholization system with alkoxy silane as a cross-linking agent and the acetone removal system with isopropenoxy silane as a cross-linking agent. Each of the above systems has its own characteristics and has various ranges of applications.

The low modulus silicone rubber is applied to large deformation places, wide seam places, airport runways, subway station seams, large roof seams, container assembly, daily necessities and the like due to low stress and high elongation. In recent years, with the development of fabricated structures, the demand for low modulus silicone rubber has been increasing more rapidly.

The preparation of low-modulus silicone rubber on the market usually adopts high-viscosity 107-base rubber, a bifunctional ketoxime type crosslinking agent, phenyltributylketoxime silane, methyl vinyl di (N-methylacetamido) silane and the like as raw materials. The silicone rubbers prepared by the above-mentioned methods have various disadvantages, such as slow tack-free, poor adhesion, insufficient modulus, insufficient relative elongation, and the like.

The bis (N-methylbenzamide) ethoxymethylsilane is adopted to prepare the RTV silicone rubber, has the advantages of fast curing, low modulus, very high elongation, good adhesion with various base materials (including various metals, coating surfaces and the like), good high and low temperature resistance, good waterproofness and the like, and is the silicone rubber with very excellent comprehensive performance. The development of a preparation method of high-quality bis (N-methylbenzamide) ethoxymethylsilane has important research significance.

In the prior art, incomplete esterification reaction is usually carried out on methyl trichlorosilane and ethanol to obtain a mixture of methyl ethoxy dichlorosilane, methyl diethoxy chlorosilane and methyl triethoxysilane, then methyl ethoxy dichlorosilane is obtained through purification, and then the methyl ethoxy dichlorosilane and N-methylbenzamide react to obtain bis (N-methylbenzamide) ethoxy methylsilane.

Chinese patent publication No. CN202010037461.1 discloses a preparation method of bis (N-methylbenzamide) ethoxymethylsilane, which comprises the following steps: (1) taking methyltrichlorosilane and methyltriethoxysilane as raw materials, adding a catalyst, heating to react under the protection of inert gas, filtering, and rectifying to obtain methylethoxydichlorosilane; (2) and (2) uniformly mixing N-methylbenzamide and an organic solvent, reacting under a heating condition, introducing ammonia gas while adding the methyl ethoxy dichlorosilane obtained in the step (1), continuously reacting, filtering, and distilling to obtain the bis (N-methylbenzamide) ethoxy methylsilane. The method has the disadvantages that the intermediate of the process needs to be purified and separated, reaction steps are added, the reaction temperature of the two steps is higher, and the energy consumption is higher.

Disclosure of Invention

The invention provides a preparation method of bis (N-methylbenzamide) ethoxy methylsilane, which aims to overcome the defects of more byproducts, low yield, difficult separation and purification and higher production energy consumption of the existing preparation method of bis (N-methylbenzamide) ethoxy methylsilane and has the advantages of less byproducts, high yield, easy separation and purification and lower production energy consumption.

In order to achieve the purpose of the invention, the technical scheme adopted by the invention is as follows:

a preparation method of bis (N-methylbenzamide) ethoxymethylsilane comprises the following steps:

A. dripping N-methylbenzamide into a methyl dichlorosilane solution, heating, adding an acid-binding agent, and reacting to obtain an intermediate product, namely bis (N-methylbenzamide) methyl hydrosilane;

B. and D, adding a catalyst and ethanol into the intermediate product system in the step A to continue reacting, and separating to obtain the bis (N-methylbenzamide) ethoxymethylsilane.

The method of the invention finishes the preparation of bis (N-methylbenzamide) ethoxy methyl silane by a one-pot method, does not need to separate and purify an intermediate product, firstly uses N-methylbenzamide and methyl dichlorosilane to form Si-N bond to obtain the intermediate product bis (N-methylbenzamide) methyl hydrogen silane, and then uses ethanol to finish the substitution of ethoxy on H on Si atom under the action of a catalyst.

Preferably, in the step A, the molar ratio of the N-methylbenzamide to the methyl dichlorosilane is 2-2.3: 1.

Preferably, in the step a, the solvent of the methyl dichlorosilane solution is at least one of toluene, xylene and petroleum ether; the acid-binding agent is ammonia.

The ammonia is selected as an acid-binding agent, so that the ammonium salt after the reaction is easy to separate, can be reused as a fertilizer raw material, and cannot generate wastewater.

Preferably, in the step A, the molar ratio of ammonia to methyl dichlorosilane is 2-2.4: 1.

Preferably, in the step A, the reaction temperature is 60-120 ℃, and the reaction time is 1-3 h.

Preferably, in the step B, the catalyst is a metal or molecular sieve catalyst with dehydrogenation function, the active component comprises at least one of nickel nitrate, nickel sulfate and nickel chloride, and the molar ratio of the catalyst to the methyl dichlorosilane is 0.005-0.1%.

Preferably, in the step B, the molar ratio of the ethanol to the methyl dichlorosilane is 0.95-1.05: 1.

Preferably, in the step B, the reaction temperature is 50-80 ℃, and the reaction time is 3-5 h.

Due to the adoption of the technical scheme, the invention has the following beneficial effects: according to the invention, methyl dichlorosilane is used as a starting raw material, and reacts with N-methylbenzamide and ethanol in sequence to obtain bis (N-methylbenzamide) ethoxymethylsilane, so that the obtained bis (N-methylbenzamide) ethoxymethylsilane has high purity, high yield, easy separation and purification, and low production energy consumption, the obtained ammonium salt can be recycled, the generated three wastes are less, and the atom utilization rate is high.

Drawings

FIG. 1 is a reaction equation of the present invention.

FIG. 2 is a gas chromatogram of bis (N-methylbenzamide) ethoxymethylsilane according to example 1 of the present invention.

Detailed Description

The invention is further described with reference to specific embodiments.

A method for preparing bis (N-methylbenzamide) ethoxymethylsilane, the reaction equation of which is shown in figure 1, comprises the following steps:

A. adding an N-methylbenzamide solution with the molar weight of 2-2.3 times that of methyl dichlorosilane into a glass lining kettle, heating to 60-120 ℃, introducing ammonia gas with the molar weight of 2-2.4 times that of methyl dichlorosilane for circulation, dropwise adding methyl dichlorosilane for reaction for 1-3 hours, and reacting to obtain an intermediate product bis (N-methylbenzamide) methyl hydrosilane;

B. controlling the temperature in the kettle to be 40-80 ℃, closing ammonia gas circulation, emptying tail gas, adding a nickel chloride catalyst into the intermediate product system in the step A, adding ethanol with the same molar weight as that of methyl dichlorosilane, continuously reacting for 3-5 hours while keeping constant pressure in the kettle, filtering reaction liquid, and performing vacuum distillation on filtrate to separate a solvent to obtain bis (N-methylbenzamide) ethoxy methyl silane.

Example 1

A. Adding 1000kg of N-methylbenzamide into a 3000L glass lining kettle, adding 1000L of toluene, replacing nitrogen, stirring and heating to 60 ℃, introducing 120kg of ammonia gas at the speed of 12.2kg/hr, starting an ammonia gas circulator to circulate, dropwise adding 380kg of methyl dichlorosilane at the speed of 40kg/h for reaction, and reacting for 3h after dropwise adding is finished to obtain an intermediate product bis (N-methylbenzamide) methyl hydrosilane;

B. controlling the temperature in the kettle to be 50 ℃, closing ammonia gas circulation, emptying tail gas, adding 100g of nickel chloride catalyst into the intermediate product system in the step A, dropwise adding 153kg of ethanol for continuous reaction, keeping the constant pressure in the kettle, continuously reacting for 5 hours, filtering reaction liquid, transporting filter residues outwards, and carrying out vacuum distillation on filtrate to separate petroleum ether to obtain 1130kg of bis (N-methylbenzamide) ethoxy methyl silane, wherein the peak area percentage of the product is 94.9%, the yield is 91.5%, and the peak height and the peak area of the impurity peak are relatively small except the solvent peak, as can be seen from figure 2.

Example 2

A. Adding 1000kg of N-methylbenzamide into a 3000L glass lining kettle, adding 1000L of 120# petroleum ether, replacing nitrogen, stirring and heating to 120 ℃, introducing 120kg of ammonia gas at the speed of 12.2kg/hr, starting an ammonia gas circulator for circulation, dropwise adding 380kg of methyl dichlorosilane at the speed of 40kg/h for reaction, and reacting for 1h after dropwise adding is finished to obtain an intermediate product, namely bis (N-methylbenzamide) methylhydrosilane;

B. controlling the temperature in the kettle to be 80 ℃, closing ammonia circulation, emptying tail gas, adding 100g of nickel chloride catalyst into the intermediate product system in the step A, dropwise adding 153kg of ethanol for continuous reaction, keeping the constant pressure in the kettle, continuously reacting for 3 hours, filtering reaction liquid, transporting filter residues outwards, and carrying out vacuum distillation on the filtrate to separate petroleum ether to obtain 1135kg of bis (N-methylbenzamide) ethoxymethylsilane, wherein the peak area percentage of the product is 94.8%, and the yield is 91.5%.

Example 3

A. Adding 1000kg of N-methylbenzamide into a 3000L glass lining kettle, adding 1000L of dimethylbenzene to replace nitrogen, stirring and heating to 90 ℃, introducing 120kg of ammonia at the speed of 12.2kg/hr, starting an ammonia circulator to circulate, dropwise adding 380kg of methyl dichlorosilane at the speed of 40kg/h for reaction, and reacting for 2h after dropwise adding is finished to obtain an intermediate product, namely bis (N-methylbenzamide) methyl hydrosilane;

B. controlling the temperature in the kettle to be 80 ℃, closing ammonia gas circulation, emptying tail gas, adding 100g of nickel chloride catalyst into the intermediate product system in the step A, dropwise adding 153kg of ethanol for continuous reaction, keeping the constant pressure in the kettle, continuously reacting for 4 hours, filtering reaction liquid, transporting filter residues outwards, and carrying out vacuum distillation on the filtrate to separate petroleum ether to obtain 1140kg of bis (N-methylbenzamide) ethoxymethylsilane, wherein the peak area percentage of the product is 95.5%, and the yield is 92.5%.

Comparative example 1

In comparison with example 1, comparative example 1 was stabilized at a reaction temperature of 40 ℃ in step B.

A. Adding 1000kg of N-methylbenzamide into a 3000L glass lining kettle, adding 1000L of toluene, replacing nitrogen, stirring and heating to 60 ℃, introducing 120kg of ammonia gas at the speed of 12.2kg/hr, starting an ammonia gas circulator to circulate, dropwise adding 380kg of methyl dichlorosilane at the speed of 40kg/h for reaction, and reacting for 3h after dropwise adding is finished to obtain an intermediate product bis (N-methylbenzamide) methyl hydrosilane;

B. controlling the temperature in the kettle to be 40 ℃, closing ammonia circulation, emptying tail gas, adding 100g of nickel chloride catalyst into the intermediate product system in the step A, dropwise adding 153kg of ethanol for continuous reaction, keeping the constant pressure in the kettle, continuously reacting for 5 hours, filtering reaction liquid, transporting filter residues outwards, and carrying out vacuum distillation on the filtrate to separate petroleum ether to obtain 1100kg of crude bis (N-methylbenzamide) ethoxy methyl silane, wherein 16.3% of the crude bis (N-methylbenzamide) methyl hydrosilane is bis (N-methylbenzamide) methyl hydrosilane, the peak area percentage of the target product is 78.9%, and the yield is 73.6%.

Comparative example 2

The reaction temperature in step A of comparative example 2 was controlled to 40 ℃ compared to that in example 1

A. Adding 1000kg of N-methylbenzamide into a 3000L glass lining kettle, adding 1000L of toluene, replacing nitrogen, stirring and heating to 40 ℃, introducing 120kg of ammonia gas at the speed of 12.2kg/hr, starting an ammonia gas circulator to circulate, dropwise adding 380kg of methyl dichlorosilane at the speed of 40kg/h for reaction, and reacting for 3h after dropwise adding is finished to obtain an intermediate product bis (N-methylbenzamide) methyl hydrosilane;

B. controlling the temperature in the kettle to be 50 ℃, closing ammonia circulation, emptying tail gas, adding 100g of nickel chloride catalyst into the intermediate product system in the step A, dropwise adding 153kg of ethanol for continuous reaction, keeping the constant pressure in the kettle, continuously reacting for 5 hours, filtering reaction liquid, transporting filter residues outwards, and carrying out vacuum distillation on the filtrate to separate petroleum ether to obtain 1130kg of crude bis (N-methylbenzamide) ethoxymethylsilane, wherein the peak area percentage of the product is 58.7%, and the yield is 56.6%.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and other variations and modifications may be made without departing from the spirit of the invention as set forth in the claims.