Methyldialkoxyhydrosilane and its synthesis method

Abstract

This application relates to methyldialkoxyhydrosilane and its synthesis method. The method includes: Step S100, mixing methyldichlorosilane and tetrabutylammonium fluoride to form a first raw material; mixing an alcohol compound, a catalyst and a solvent to form a second raw material, where the catalyst includes 4-ethylaniline and / or 4-propylaniline; Step S200, adding the second raw material to the first raw material and then reacting to obtain a reaction mixture containing methyldialkoxyhydrosilane. The synthesis method of this application can improve the yield of methyldialkoxyhydrosilane.

Description

Technical Field

[0001] This application relates to the technical field of material production, and more specifically, to methyldialkoxyhydroxysilane and its synthesis method. Background Art

[0002] When preparing methyldialkoxyhydroxysilane, it is inevitable to produce by-product hydrogen chloride, and hydrogen chloride may further undergo multiple side reactions with the raw materials, resulting in a low yield of methyldialkoxyhydroxysilane.

[0003] Therefore, it is necessary to improve the yield of methyldialkoxyhydroxysilane. Summary of the Invention

[0004] This application provides methyldialkoxyhydroxysilane and its synthesis method, and the synthesis method can improve the yield of methyldialkoxyhydroxysilane.

[0005] In a first aspect, this application proposes a method for synthesizing methyldialkoxyhydroxysilane, including:

[0006] Step S100, mixing methyldichlorosilane and tetrabutylammonium fluoride to form a first raw material; mixing an alcohol compound, a catalyst, and a solvent to form a second raw material, and the catalyst includes 4-ethylaniline and / or 4-propylaniline;

[0007] Step S200, adding the second raw material to the first raw material and then reacting to obtain a reaction mixture containing methyldialkoxyhydroxysilane.

[0008] In some embodiments, based on the total molar amount of the first raw material and the second raw material, the ratio of the molar percentage content of tetrabutylammonium fluoride to the molar percentage content of methyldichlorosilane is 0.01 to 0.03.

[0009] In some embodiments, based on the total molar amount of the first raw material and the second raw material, the ratio of the molar percentage content of the alcohol compound to the molar percentage content of methyldichlorosilane is 1.9 to 2.1.

[0010] In some embodiments, based on the total molar amount of the first raw material and the second raw material, the ratio of the molar percentage content of the catalyst to the molar percentage content of methyldichlorosilane is 1.9 to 2.0.

[0011] In some embodiments, based on the total mass of the first raw material and the second raw material, the ratio of the mass percentage content of the solvent to the mass percentage content of the catalyst can be 3 to 5.

[0012] In some embodiments, in step S200, the temperature is controlled to be 20°C to 30°C.

[0013] In some embodiments, in step S200, the reaction time is controlled to be 12 hours to 24 hours.

[0014] In some embodiments, step S300: Filter the reaction mixture at room temperature to obtain a filtrate, and rinse the filter cake with the solvent to obtain the rinsed filter cake and the rinsing solution;

[0015] In step S500, the mixture of the filtrate and the rinsing solution obtained in step S300 is subjected to atmospheric distillation to separate each fraction.

[0016] In some embodiments, the alcohol compound includes methanol, and the methyldialkoxyhydrogensilane includes methyldimethoxysilane.

[0017] In some embodiments, the alcohol compound includes ethanol, and the methyldialkoxyhydrogensilane includes methyldiethoxysilane.

[0018] In a second aspect, the present application provides a methyldialkoxyhydrogensilane prepared by the method according to any one of the embodiments of the first aspect of the present application.

[0019] According to the method of the embodiments of the present application, 4-ethylaniline and / or 4-propylaniline are used as catalysts, and the reaction process can be achieved by a one-pot method, and the reaction conditions are relatively mild, and the reaction can be completed at room temperature. Due to the lower reaction temperature adopted in the present application, the hydrochloride salt formed by 4-ethylaniline and / or 4-propylaniline and hydrogen chloride can precipitate out more thoroughly from the reaction solution, and less free hydrogen chloride is decomposed and released; the yield of the purified methyldimethoxysilane (or methyldiethoxysilane) prepared in the present application can reach more than 86%, and the yield is relatively high. Moreover, the solvent and 4-ethylaniline (or 4-propylaniline) adopted in the present application can be recycled; the volatile losses of the solvent and the product in the reaction are smaller, and the required energy consumption is also lower; the comprehensive cost is lower than various methods described in the background solution. Detailed Embodiments

[0020] The embodiments of the present application will be described in detail below. The embodiments of the present application should not be construed as limiting the present application.

[0021] In addition, sometimes quantities, ratios, and other numerical values are presented in a range format in this document. It should be understood that such range formats are for convenience and brevity, and should be understood flexibly, including not only the explicitly specified numerical values as range limits, but also all individual numerical values or sub-ranges included within the range, as if each numerical value and sub-range were explicitly specified.

[0022] In the specific embodiments and claims, a list of items connected by terms such as "one or more of", "one or more of", "a mixture of one or two or more of", or other similar terms may mean any combination of the listed items. For example, if items A and B are listed, then the phrase "at least one of A and B" means only A; only B; or A and B. In another example, if items A, B, and C are listed, then the phrase "at least one of A, B, and C" means only A; or only B; only C; A and B (excluding C); A and C (excluding B); B and C (excluding A); or all of A, B, and C. Item A may include a single element or multiple elements. Item B may include a single element or multiple elements. Item C may include a single element or multiple elements.

[0023] Methyldialkoxysilane includes methyldimethoxysilane and / or methyldiethoxysilane, etc., which are important chemical intermediates. In the related art, in order to synthesize methyldialkoxysilane, methyldichlorosilane and methanol (or ethanol) are directly reacted, as shown by the following equation:

[0024]

[0025] The by-product hydrogen chloride generated by the above reaction will react with methanol (or ethanol) to generate water, and the water will further undergo multiple side reactions with the product and the raw material methyldichlorosilane; thereby resulting in low conversion rate and poor purity of the target; the yield of the purified target product is less than 50%.

[0026] In order to improve the yield of the product, it is necessary to remove the by-product hydrogen chloride as much as possible. In the related art, there are various methods for removing the by-product hydrogen chloride, which are specifically as follows:

[0027] The first method is to add a special acid-binding agent that basically does not undergo side reactions with the raw materials and products to the reaction system, such as magnesium powder, aluminum powder, sodium 2,6-di-tert-butyl-p-cresolate, etc. However, their solubility in the reaction system is not good, and a large excess is required to have a better acid-binding effect; moreover, the excess acid-binding agent is difficult to separate, purify, and recycle, and the overall cost is high.

[0028] The second method is to select a weakly polar solvent with poor solubility in hydrogen chloride, and at the same time continuously introduce a nitrogen gas stream into the reaction system to carry away the by-product hydrogen chloride gas, thereby reducing side reactions; it can improve the yield of methyldiethoxysilane to a certain extent. However, the effect of removing hydrogen chloride by this scheme is not thorough, and the nitrogen gas stream will cause a volatile loss of the solvent and the product to reach 10-20%.

[0029] Thirdly, methanol (or ethanol) is heated to boiling in the bottom heating device of the rectification unit, and its vapor rises along the packing in the rectification column; dichloromethylsilane is added dropwise from the top of the column; the two come into contact and react on the surface of the rectification packing. The generated hydrogen chloride gas escapes to the upper part of the rectification column; the methanol (or ethanol) with a higher boiling point and the generated product are concentrated in the middle and lower parts of the rectification column; thus, the contact between hydrogen chloride and alcohols and side reactions are reduced. This solution can improve the yield to a certain extent, but it also has the disadvantage of high energy consumption.

[0030] In view of the fact that the above methods all have different problems and the overall yield is low, the applicant has proposed a synthesis method. The synthesis method uses 4-ethylaniline or 4-propylaniline as an acid-binding agent and a key catalyst, and realizes the reaction of methyldichlorosilane with methanol (or ethanol) at a relatively low reaction temperature of 20 - 30°C. The purified yield of preparing methyldimethoxysilane (or methyldiethoxysilane) reaches more than 86%, and the recycling rate of 4-ethylaniline (or 4-propylaniline) reaches about 95%, which is lower than the comprehensive cost of the foregoing various solutions. Next, the method will be described in detail.

[0031] Method for synthesizing methyldialkoxyhydrosilane

[0032] The method includes: Step S100, mixing methyldichlorosilane and tetrabutylammonium fluoride as the first raw material; mixing an alcohol compound, a catalyst and a solvent as the second raw material; Step S200, adding the second raw material to the first raw material and then reacting to obtain a reaction mixture containing methyldialkoxyhydrosilane.

[0033] In some embodiments, based on the total molar amount of the first raw material and the second raw material, the ratio of the molar percentage content of tetrabutylammonium fluoride to the molar percentage content of methyldichlorosilane is 0.01 to 0.03. Exemplarily, the ratio can be 0.01, 0.02, 0.03 or the range composed of any two of the above values.

[0034] When the ratio of the molar percentage content of tetrabutylammonium fluoride to the molar percentage content of methyldichlorosilane is within the above range, the reaction rate can be further increased and the implementation cost can be reduced.

[0035] In some embodiments, the alcohol compound is related to the type of product. For example, methanol is selected when preparing methyldimethoxysilane, and ethanol is selected when preparing methyldiethoxysilane, etc.

[0036] In some embodiments, based on the total molar amount of the first raw material and the second raw material, the ratio of the molar percentage content of the alcohol compound to the molar percentage content of methyldichlorosilane is 1.9 to 2.1. Exemplarily, the ratio can be 1.9, 2.0, 2.1 or a range composed of any two of the above values.

[0037] When the ratio of the molar percentage content of the alcohol compound to the molar percentage content of methyldichlorosilane is within the above range, the conversion rate of the target product is further improved; and less alcohol compound remains in the product, reducing the risk that the residual alcohol compound reacts with the hydrochloride salt of 4-ethylaniline (or 4-propylaniline) to generate water and further the side reaction between the water and the target product.

[0038] In some embodiments, the catalyst may include 4-ethylaniline and / or 4-propylaniline.

[0039] In some embodiments, based on the total molar amount of the first raw material and the second raw material, the ratio of the molar percentage content of the catalyst to the molar percentage content of methyldichlorosilane is 1.9 to 2.0. Exemplarily, the ratio can be 1.9, 1.95, 2.0 or a range composed of any two of the above values.

[0040] While playing the catalytic function, the catalyst also has an acid-binding effect. When the ratio of the mass percentage content of the catalyst to the mass percentage content of methyldichlorosilane is within the above range, the conversion rate of the target product can be further improved, and the residual amount of 4-ethylaniline (or 4-propylaniline) in the target product is reduced. In subsequent purification processes such as the distillation separation process, the crude product of the target product needs to be heated to a relatively high temperature; the slightly basic 4-ethylaniline or 4-propylaniline can catalyze the disproportionation side reaction of the silicon-hydrogen bond in the target product at high temperature, resulting in a decrease in the distillation yield of the target product. Residual less ethylaniline (or 4-propylaniline) can reduce or avoid the disproportionation side reaction of the target product.

[0041] In some embodiments, the selection of the solvent type can also be adjusted according to the type of the product. For example, if the product is methyl dimethoxysilane, the solvent may include toluene and / or xylene; if the product is methyl diethoxysilane, the solvent may include n-hexane and / or xylene. It should be noted that xylene may include one or more of ortho-xylene, meta-xylene and para-xylene, or mixed xylene (a mixture of any 2-3 xylene isomers).

[0042] In some embodiments, based on the total mass of the first raw material and the second raw material, the ratio of the mass percentage of the solvent to the mass percentage of the catalyst can be 3 to 5. Exemplarily, the ratio can be 3, 4, 5, or a range composed of any two of the above values.

[0043] During the reaction process of this application, a large amount of hydrochloride salts of 4-ethylaniline (or 4-propylaniline) may be generated and precipitate as insoluble substances. When the ratio of the mass percentage of the solvent to the mass percentage of the catalyst is within the above range, the reaction system will not be too viscous and is easy to stir and mix; and since the amount of solvent used is not excessive, less energy is consumed during the later rectification separation of the solvent and the target product.

[0044] In step S200, in some embodiments, the temperature is controlled to be 20°C to 30°C.

[0045] Controlling the temperature within the above temperature range, the reaction rate is relatively fast and the reaction is relatively complete; and it can reduce the side reaction of the alcohol compound reacting with the hydrochloride salt of 4-ethylaniline (or 4-propylaniline) to generate water, thereby improving the conversion rate of the target product.

[0046] In step S200, in some embodiments, the reaction time is controlled to be 12 hours to 24 hours.

[0047] Controlling the reaction time within the above time range, the reaction is relatively complete and the conversion rate can be further improved.

[0048] Exemplarily, step S200 is specifically: controlling the mixing temperature of methyldichlorosilane and tetrabutylammonium fluoride in the first raw material to be between 20°C and 30°C, and slowly dropping the second raw material while stirring. After the dropping is completed, continue to stir and react at 20°C - 30°C for 12 hours - 24 hours.

[0049] This application starts from methyldichlorosilane and alcohol compounds, and at a relatively low temperature, for example, 20 - 30°C, realizes the following 4 reactions in one pot to finally obtain methyldimethoxysilane (or methyldiethoxysilane):

[0050]

[0051] This application preferably uses 4-ethylaniline and / or 4-propylaniline as key catalysts and acid-binding agents, which have the following advantages:

[0052] The solubility of 4-ethylaniline and / or 4-propylaniline in weakly polar organic solvents is better than that of aniline, and their miscibility with water is much less than that of aniline. Therefore, they can play a better catalytic role in non-polar solvents; and their recovery rates are also higher during neutralization extraction and water washing. Moreover, after water washing and liquid separation of the mixture of 4-ethylaniline and / or 4-propylaniline and non-polar solvents, the water content can be stably lower than 0.04%, and it can be reused without further drying and water treatment. In contrast, after water washing and liquid separation of the mixture of aniline and non-polar solvents, the water content of the recovered mixture is relatively high; even if the proportion of non-polar solvents is increased, the water content is still above 0.3%, and water treatment must be carried out before reuse. Other anilines with larger alkyl substituents are not only rare in the market and relatively expensive; but also their corresponding hydrochlorides have better solubility in organic solvents and less precipitation from the reaction system, which is not beneficial to reducing side reactions and increasing the recovery rate.

[0053] This application at least also has the following three advantages:

[0054] First, this application realizes four reactions through a one-pot method, all of which can occur at a relatively low temperature of 20-30°C; while for known other solutions outside this application, the required reaction temperature is at least 45-55°C, or even the reflux temperature of alcohols. The decrease in this temperature significantly slows down or even makes it difficult for side reactions between hydrogen chloride and alcohols and subsequent multiple side reactions to occur. The said side reactions are as follows:

[0055]

[0056] Second, the lower reaction temperature adopted in this application enables the hydrochloride salt formed by 4-ethylaniline and / or 4-propylaniline and hydrogen chloride to precipitate more thoroughly from the reaction solution, and less free hydrogen chloride is decomposed and released; as shown in the following equation:

[0057]

[0058] This solution not only further suppresses multiple side reactions caused by hydrogen chloride, but also enables this application to obtain a recovery rate of more than 95% of 4-ethylaniline (or 4-propylaniline).

[0059] Third, this application does not require continuous injection of a nitrogen gas stream, reducing the volatile loss of solvents and products; nor does it require keeping the reaction and distillation equipment at a relatively high temperature for a long time, reducing energy consumption.

[0060] In summary, the yield of purified methyl dimethoxysilane (or methyl diethoxysilane) prepared in this application can reach over 86%, with a relatively high yield. Moreover, the solvents and 4-ethylaniline (or 4-propylaniline) used in this application can be recycled; the volatile losses of the solvents and products during the reaction are smaller, and the required energy consumption is also lower; the comprehensive cost is lower than that of various methods described in the background solutions.

[0061] In some embodiments, the method may further include step S300: a filtration step; specifically, the reaction mixture is filtered at room temperature, and the filter cake can be rinsed with the solvent in step S200, and the rinsing liquid generated after rinsing is combined with the filtrate.

[0062] In some embodiments, the amount of the solvent in step S300 can be 1 to 2 times the mass of the catalyst in step S100.

[0063] When the solvent in step S400 is used in the above amount, the following effects are achieved:

[0064] Since a part of the target product is contained and remained in the filter cake, it is necessary to wash the filter cake to allow this part of the target product to enter the washing liquid and then (together with the target product in the filtrate) be separated by rectification. When the amount of the washing solvent is too small, the washing effect on the filter cake is not good; when the amount of the solvent is too large, more energy consumption is required for separating the solvent and the target product by rectification in the later stage. Considering the above situations, the inventors of this application preferably set the ratio of the mass percentage of the washing solvent to the mass percentage of the catalyst between 1 and 2.

[0065] In some embodiments, the filtration temperature in step S300 and the temperature for rinsing the filter cake can both be room temperature.

[0066] In some embodiments, the method may further include step S400, a neutralization extraction and washing step. Specifically, the (washed) filter cake obtained in step S300 is slowly added to a mixture of a solvent and an alkaline aqueous solution for neutralization extraction; after all the solids disappear, liquid separation is performed. The organic layer is washed with water 2 - 3 times, and the washed organic layer is a mixture of the catalyst and the solvent, which can be recycled together for use in step S100.

[0067] In some embodiments, the solvent described in step S400 can have the same composition as the solvent used in step S100.

[0068] In some embodiments, the amount of the solvent used for neutralization extraction in step S400 can be 3 - 5 times the mass ratio of the catalyst added in step S100.

[0069] In some embodiments, the aqueous alkaline solution used for neutralizing the filter cake in step S400 may include one or more of aqueous solutions of sodium hydroxide, sodium carbonate, and sodium bicarbonate.

[0070] In some embodiments, the concentration of the aqueous alkaline solution used for neutralizing the filter cake in step S400 is between 10% and 30%.

[0071] In some embodiments, the dosage of the aqueous alkaline solution used for neutralizing the filter cake in step S400, based on the number of hydrogen ions it can neutralize, is 2.2 - 2.4 times the equivalent amount of methyl dichlorosilane added in step S100.

[0072] In some embodiments, the dosage of water during the water washing in step S400 is 2 - 3 times the mass ratio of the catalyst used in step S100.

[0073] In some embodiments, the number of times of water washing in step S400 is 2 - 3 times.

[0074] In some embodiments, the temperature during neutralization, liquid separation, and washing in step S400 can all be at room temperature.

[0075] In some embodiments, the method further includes step S500 of rectifying and separating the product and the solvent. Specifically, the mixture of the filtrate and the rinsing liquid obtained in step S300 is subjected to atmospheric rectification to separate each fraction. During rectification, according to the differences in the target product and the components of the solvent used, fractions with different boiling ranges are collected separately, and the following several main components can be separated:

[0076] Methyl dimethoxysilane (boiling range 61 - 62 °C) and toluene (boiling range about 109 - 110 °C); or methyl dimethoxysilane (boiling range 61 - 62 °C) and xylene (boiling range about 137 - 144 °C according to the differences in the xylene isomers used).

[0077] Methyl diethoxysilane (boiling range 94 - 95 °C) and n - hexane (boiling range 69 - 70 °C); or methyl diethoxysilane (boiling range 61 - 62 °C) and xylene (boiling range about 137 - 144 °C according to the differences in the xylene isomers used).

[0078] The solvents such as n - hexane, toluene, and xylene obtained by rectification can be recycled and reused.

[0079] Examples

[0080] Hereinafter, embodiments of the present application will be described. The embodiments described below are exemplary and are only used to explain the present application, and should not be construed as a limitation of the present application. For those without specific technical or conditions noted in the embodiments, the techniques or conditions described in the literature in the art or according to the product specifications are followed. For reagents or instruments without the manufacturer noted, they are all conventional products that can be obtained through commercial purchase.

[0081] Example 1: Preparation of methyldimethoxysilane.

[0082] The preparation process is as follows:

[0083]

[0084] 1.1. Add 114 g (1 mol) of methyldichlorosilane and 2.61 g (0.01 mol) of tetrabutylammonium fluoride to a 3000 ml reaction flask (A), and stir and mix well. In another 2000 ml reaction flask (B), add 60.8 g (1.9 mol) of methanol, 230 g (1.9 mol) of 4-ethylaniline, and 920 g of toluene, and stir and mix well.

[0085] 1.2. While stirring the reaction flask (A), keep the liquid temperature between 25 - 30 °C with a water bath; then slowly drop the mixture in flask (B) into flask (A). There will be an exothermic temperature rise in flask (A); control the dropping rate and the water bath temperature so that the liquid temperature in flask (A) always remains between 25 - 30 °C. After the dropping is complete, keep the liquid temperature in reaction flask (A) between 25 - 30 °C and stir for 24 hours.

[0086] 1.3. Filter the reaction mixture obtained in 1.2; wash the filter cake with 230 g of toluene, and incorporate the washing liquid into the filtrate.

[0087] 1.4. In a 5000 ml reaction flask (C), add 1272 g of 10% sodium carbonate (containing 1.2 mol of sodium carbonate) aqueous solution; and 920 g of toluene. While stirring, add the filter cake obtained in 1.3 in batches slowly; there is obvious heat release during the addition, cool down with a water bath outside the reaction flask to keep the reaction liquid temperature close to room temperature. After the addition, continue to stir until all the solids disappear, then separate the layers. The upper organic layer is washed with tap water 3 times, 460 g of water each time. The washed organic layer is a mixture of 4-ethylaniline and toluene, which can be recycled; analyzed by gas chromatography internal standard method after sampling, it contains about 220 g of 4-ethylaniline (recovery rate 95.6%).

[0088] 1.5. The filtrate obtained in 1.3 is subjected to atmospheric distillation. Approximately 87 g of the fraction with a boiling range of 61 - 62°C is collected, and the main component is methyl dimethoxysilane, with a yield of 86.4% (calculated based on methanol), and the gas chromatographic purity is approximately 97.4%. Approximately 1067 g of the fraction with a boiling range of 108 - 110°C is collected, and the main component is toluene, with a recovery rate of approximately 92.8%.

[0089] Example 2: Preparation of methyl dimethoxysilane.

[0090] The preparation process is as follows:

[0091]

[0092] 2.1. Add 114 g (1 mol) of methyl dichlorosilane and 7.83 g (0.03 mol) of tetrabutylammonium fluoride to a 3000 ml reaction flask (A), and stir well to mix. In another 2000 ml reaction flask (B), add 60.8 g (1.9 mol) of methanol, 230 g (1.9 mol) of 4-ethylaniline, and 920 g of toluene, and stir well to mix.

[0093] 2.2. While stirring the reaction flask (A), keep the liquid temperature between 25 - 30°C using a water bath; then slowly drip the mixture in flask (B) into flask (A). There will be an exothermic temperature increase in flask (A); control the dropping rate and the water bath temperature so that the liquid temperature in flask (A) always remains between 25 - 30°C. After the dropping is complete, continue to stir the reaction flask (A) at a liquid temperature between 25 - 30°C for 12 hours.

[0094] 2.3. Filter the reaction mixture obtained in 2.2; wash the filter cake with 230 g of toluene, and incorporate the washing liquid into the filtrate.

[0095] 2.4. Add 1272 g of a 10% sodium carbonate (containing 1.2 mol of sodium carbonate) aqueous solution and 920 g of toluene to a 5000 ml reaction flask (C). While stirring, slowly add the filter cake obtained in 2.3 in batches; there is obvious heat release during the addition, and cool down the reaction flask externally using a water bath to keep the reaction liquid temperature close to room temperature. After the addition is complete, continue to stir until all the solids disappear, and then separate the layers. The upper organic layer is washed with tap water 3 times, with 460 g of water each time. The washed organic layer is a mixture of 4-ethylaniline and toluene, which can be recycled; analyzed by gas chromatography internal standard method after sampling, it contains approximately 221 g of 4-ethylaniline (recovery rate 96.1%).

[0096] 2.5. The filtrate obtained in 2.3 is subjected to atmospheric distillation. Approximately 86 g of the fraction with a boiling range of 61 - 62 °C is collected, with the main component being methyldimethoxysilane, and the yield is 85.4% (based on methanol), and the gas chromatographic purity is approximately 97.3%. Approximately 1076 g of the fraction with a boiling range of 108 - 110 °C is collected, with the main component being toluene, and the recovery rate is approximately 93.6%.

[0097] Example 3: Preparation of methyldimethoxysilane.

[0098] The preparation process is as follows:

[0099]

[0100] 3.1. Add 114 g (1 mol) of methyldichlorosilane and 5.22 g (0.02 mol) of tetrabutylammonium fluoride to a 3000 ml reaction flask (A), and stir to mix evenly. Use another 2000 ml reaction flask (B) to add 67.2 g (2.1 mol) of methanol, 230 g (1.9 mol) of 4-ethylaniline, and 920 g of mixed xylene, and stir to mix evenly.

[0101] 3.2. While stirring the reaction flask (A), keep the liquid temperature between 25 - 30 °C using a water bath; then slowly add the mixed liquid in flask (B) to flask (A). There will be an exothermic temperature increase in flask (A); control the dropping rate and the water bath temperature so that the liquid temperature in flask (A) always remains between 25 - 30 °C. After the addition is complete, continue to stir the reaction flask (A) at a liquid temperature of 25 - 30 °C for 16 hours.

[0102] 3.3. Filter the reaction mixture obtained in 3.2; wash the filter cake with 230 g of mixed xylene, and incorporate the washing liquid into the filtrate.

[0103] 3.4. Add 1272 g of a 10% sodium carbonate (containing 1.2 mol of sodium carbonate) aqueous solution and 920 g of mixed xylene to a 5000 ml reaction flask (C). While stirring, slowly add the filter cake obtained in 3.3 in batches; there is obvious heat release during the addition, and cool down the reaction flask externally using a water bath to keep the reaction liquid temperature close to room temperature. After the addition is complete, continue to stir until all the solids disappear, and then separate the layers. Wash the upper organic layer with tap water 3 times, with 460 g of water each time. The organic layer after washing is a mixture of 4-ethylaniline and mixed xylene, which can be recycled; analyzed by gas chromatography internal standard method after sampling, it contains approximately 221 g of 4-ethylaniline (recovery rate 96.1%).

[0104] 3.5. Subject the filtrate obtained in 3.3 to atmospheric distillation. Collect approximately 92 g of the fraction with a boiling range of 61 - 62°C, the main component being methyl dimethoxysilane, with a yield of 86.8% (calculated based on methyl dichlorosilane) and a gas chromatographic purity of approximately 97.7%. Collect approximately 1100 g of the fraction with a boiling range of 137 - 144°C, the main component being mixed xylene, with a recovery rate of approximately 95.6%.

[0105] Example 4: Preparation of methyl diethoxysilane.

[0106] The preparation process is as follows:

[0107]

[0108] 4.1. Add 114 g (1 mol) of methyl dichlorosilane and 5.22 g (0.02 mol) of tetrabutylammonium fluoride to a 3000 ml reaction flask (A), and stir to mix evenly. Use another 2000 ml reaction flask (B) to add 96.6 g (2.1 mol) of ethanol, 270 g (2.0 mol) of 4-propylaniline, and 1080 g of mixed xylene, and stir to mix evenly.

[0109] 4.2. While stirring the reaction flask (A), maintain the liquid temperature between 25 - 30°C using a water bath; then slowly drip the mixture in flask (B) into flask (A). There will be an exothermic temperature increase in flask (A); control the dropping rate and the water bath temperature so that the liquid temperature in flask (A) always remains between 25 - 30°C. After the dropping is complete, continue to stir the reaction flask (A) at a liquid temperature of 25 - 30°C for 16 hours.

[0110] 4.3. Filter the reaction mixture obtained in 4.2; wash the filter cake with 270 g of mixed xylene, and incorporate the washing liquid into the filtrate.

[0111] 4.4. Add 294 g of 30% sodium hydroxide (containing 2.2 mol of sodium hydroxide)

[0112] aqueous solution; and 1080 g of mixed xylene. While stirring, slowly add the filter cake obtained in 4.3 in batches; there is obvious heat release during the addition, and cool the reaction flask externally with a water bath to keep the reaction liquid temperature close to room temperature. After the addition is complete, continue to stir until all the solids disappear, then separate the layers. Wash the upper organic layer with tap water 2 times, each time using 810 g of water. The organic layer after washing is a mixture of 4-propylaniline and mixed xylene, which can be recycled; analyzed by gas chromatography internal standard method after sampling, it contains approximately 257 g of 4-propylaniline (recovery rate 95.1%).

[0113] 4.5. Subject the filtrate obtained in 4.3 to atmospheric distillation. Collect approximately 116 g of the fraction with a boiling range of 94 - 95°C, the main component being methyldiethoxysilane (calculated based on methyldichlorosilane), with a yield of 86.6% and a gas chromatography purity of approximately 98.3%. Collect approximately 1288 g of the fraction with a boiling range of 137 - 144°C, the main component being mixed xylene, with a recovery rate of approximately 95.4%.

[0114] Example 5: Preparation of methyldiethoxysilane.

[0115] The preparation process is as follows:

[0116]

[0117] 5.1. Add 114 g (1 mol) of methyldichlorosilane and 5.22 g (0.02 mol) of tetrabutylammonium fluoride to a 5000 ml reaction flask (A), and stir to mix evenly. Use another 3000 ml reaction flask (B) to add 92 g (2.0 mol) of ethanol, 270 g (2.0 mol) of 4-propylaniline, and 1350 g of n-hexane, and stir to mix evenly.

[0118] 5.2. While stirring the reaction flask (A), maintain the liquid temperature between 20 - 25°C using a water bath; then slowly drip the mixture in flask (B) into flask (A). There will be an exothermic temperature rise in flask (A); control the dropping rate and the water bath temperature so that the liquid temperature in flask (A) always remains between 20 - 25°C. After the dropping is complete, continue to stir the reaction flask (A) at a liquid temperature between 20 - 25°C for 20 hours.

[0119] 5.3. Filter the reaction mixture obtained in 5.2; wash the filter cake with 270 g of n-hexane, and incorporate the washing liquid into the filtrate.

[0120] 5.4. Add 294 g of 30% sodium hydroxide (containing 2.2 mol of sodium hydroxide)

[0121] aqueous solution; and 1350 g of n-hexane. While stirring, slowly add the filter cake obtained in 5.3 in batches; there is obvious heat release during the addition, and cool down the reaction flask externally using a water bath to keep the reaction liquid temperature close to room temperature. After the addition is complete, continue to stir until all the solids disappear, then separate the layers. Wash the upper organic layer with tap water 2 times, each time using 810 g of water. The organic layer after washing is a mixture of 4-propylaniline and n-hexane, which can be recycled; by sampling and analyzing using the gas chromatography internal standard method, it contains approximately 262 g of 4-propylaniline (recovery rate 97.0%).

[0122] 5.5. Subject the filtrate obtained in 5.3 to atmospheric distillation. Collect approximately 1475 g of the fraction with a boiling range of 69 - 70°C, the main component being n - hexane, with a recovery rate of approximately 91%. Collect approximately 117 g of the fraction with a boiling range of 94 - 95°C, the main component being methyldiethoxysilane (calculated based on methyldichlorosilane), with a yield of 87.3% and a gas chromatographic purity of approximately 97.7%.

[0123] Example 6: Preparation of methyldiethoxysilane.

[0124] The preparation process is as follows:

[0125]

[0126] 6.1. Add 114 g (1 mol) of methyldichlorosilane and 5.22 g (0.02 mol) of tetrabutylammonium fluoride to a 3000 - ml reaction flask (A), and stir to mix evenly. In another 2000 - ml reaction flask (B), add 92 g (2.0 mol) of ethanol, 270 g (2.0 mol) of 4 - propylaniline, and 810 g of n - hexane, and stir to mix evenly.

[0127] 6.2. While stirring the reaction flask (A), maintain the liquid temperature between 20 - 25°C using a water bath; then slowly drip the mixture in flask (B) into flask (A). There will be an exothermic temperature increase in flask (A); control the dripping rate and the water - bath temperature so that the liquid temperature in flask (A) always remains between 20 - 25°C. After the dripping is complete, continue to stir the reaction flask (A) at a liquid temperature of 20 - 25°C for 20 hours.

[0128] 6.3. Filter the reaction mixture obtained in 6.2; wash the filter cake with 540 g of n - hexane, and incorporate the washing liquid into the filtrate.

[0129] 6.4. In a 3000 - ml reaction flask (C), add 294 g of 30% sodium hydroxide (containing 2.2 mol of sodium hydroxide)

[0130] aqueous solution; and 810 g of n - hexane. While stirring, slowly add the filter cake obtained in 6.3 in batches; there is obvious heat release during the addition, and cool the reaction flask externally with a water bath to keep the reaction liquid temperature close to room temperature. After the addition is complete, continue to stir until all the solids disappear, then separate the layers. Wash the upper organic layer with tap water 2 times, 810 g of water each time. The organic layer after washing is a mixture of 4 - propylaniline and n - hexane, which can be recycled; by sampling and analyzing using the gas chromatographic internal standard method, it contains approximately 261 g of 4 - propylaniline (recovery rate 96.6%).

[0131] 6.5. The filtrate obtained in 6.3 is subjected to atmospheric distillation. Approximately 1232 g of the fraction with a boiling range of 69 - 70 °C is collected, with the main component being n - hexane and the recovery rate being approximately 91.3%. Approximately 118 g of the fraction with a boiling range of 94 - 95 °C is collected, with the main component being methyldiethoxysilane (calculated based on methyldichlorosilane), the yield being 88.1%, and the gas chromatographic purity being approximately 97.5%.

[0132] Although the illustrative embodiments have been demonstrated and described, those skilled in the art should understand that the above - mentioned embodiments cannot be construed as limitations on this application, and changes, substitutions, and modifications can be made to the embodiments without departing from the spirit, principle, and scope of this application.

Claims

1. A method for synthesizing methyldialkoxyhydrosilane, comprising: Step S100: Mix methyldichlorosilane and tetrabutylammonium fluoride to form a first raw material; mix an alcohol compound, a catalyst, and a solvent to form a second raw material, wherein the catalyst is 4-ethylaniline and / or 4-propylaniline; the alcohol compound is methanol or ethanol; Step S200: Add the second raw material to the first raw material and then carry out a reaction to obtain a reaction mixture containing methyldialkoxyhydrosilane, wherein, Based on the total molar amount of the first raw material and the second raw material, the ratio of the molar percentage content of tetrabutylammonium fluoride to the molar percentage content of methyldichlorosilane is 0.01 to 0.03; Based on the total molar amount of the first raw material and the second raw material, the ratio of the molar percentage content of the alcohol compound to the molar percentage content of methyldichlorosilane is 1.9 to 2.1; Based on the total molar amount of the first raw material and the second raw material, the ratio of the molar percentage content of the catalyst to the molar percentage content of methyldichlorosilane is 1.9 to 2.0; Based on the total mass of the first raw material and the second raw material, the ratio of the mass percentage content of the solvent to the mass percentage content of the catalyst is 3 to 5; In step S200, control the temperature to be 20°C to 30°C; In step S200, control the reaction time to be 12 hours to 24 hours.

2. The method according to claim 1, further comprising: Step S300: Filter the reaction mixture at room temperature to obtain a filtrate, and wash the filter cake with the solvent to obtain a washed filter cake and a washing solution; Step S500: Carry out atmospheric distillation on the mixture of the filtrate and the washing solution obtained in step S300 to separate each fraction.

3. The method according to claim 1, wherein, The alcohol compound is methanol, and the methyldialkoxyhydrosilane includes methyldimethoxysilane; and / or The alcohol compound is ethanol, and the methyldialkoxyhydrosilane includes methyldiethoxysilane.

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