A kind of synthesis process of methylvinyldichlorosilane

Abstract

The present application relates to the technical field of organic synthesis, and specifically discloses a synthesis process for methylvinyldichlorosilane. A synthesis process for methylvinyldichlorosilane comprises the following steps: adding acetylene and monomethyldichlorosilane to methylvinyldichlorosilane, heating, pressurizing, reacting for a period of time under the action of hexahydrate chloroplatinic acid catalyst, and separating by rectification to obtain methylvinyldichlorosilane. The synthesis process for methylvinyldichlorosilane of the present application has the advantages of increasing the yield of methylvinyldichlorosilane, being safe and environmentally friendly, and achieving benzene-free through the synergistic effect between the various steps.

Description

Technical Field

[0001] The present application relates to the technical field of organic synthesis, and in particular to a synthesis process of methylvinyldichlorosilane. Background Art

[0002] With the continuous development of organic synthesis technology, people are paying more and more attention to environmental protection and safety in organic synthesis production. Methylvinyldichlorosilane is a colorless liquid with an irritating odor. Due to its vinyl unsaturated bonds, it can be used as an excellent functional organosilane monomer to synthesize other functional organosilicon intermediates. It can also be used as an active end-capping agent in the production of high-performance silicone oils and silicone rubbers.

[0003] Currently, numerous methods for synthesizing methylvinyldichlorosilane are disclosed in the prior art, including the Grignard method, the disproportionation method, the thermal condensation method, and the addition method. However, these technical solutions suffer from the following deficiencies in practical application: existing methylvinyldichlorosilane synthesis processes cannot simultaneously ensure safety and increase yield. Therefore, there is an urgent need to develop a synthesis process for methylvinyldichlorosilane with higher yield. Summary of the Invention

[0004] In order to improve the yield of methylvinyldichlorosilane while ensuring environmental safety, the present application provides a synthesis process of methylvinyldichlorosilane.

[0005] In a first aspect, the present application provides a synthesis process of methylvinyldichlorosilane, which adopts the following technical scheme: a synthesis process of methylvinyldichlorosilane, comprising the following steps: adding acetylene and monomethyldichlorosilane to methylvinyldichlorosilane, heating and pressurizing under the action of hexahydrate chloroplatinic acid catalyst, reacting for a period of time, and distilling and separating to obtain methylvinyldichlorosilane.

[0006] Furthermore, a synthesis process for methylvinyldichlorosilane comprises the following steps: heating and gasifying monomethyldichlorosilane, adding it to methylvinyldichlorosilane, adding acetylene, heating and pressurizing under the action of hexahydrate chloroplatinic acid catalyst, reacting for a period of time, and separating by distillation at a temperature of 90-140°C to obtain methylvinyldichlorosilane.

[0007] By adopting the above technical solution, the synthesis process of methylvinyldichlorosilane of the present application enables the reaction to proceed continuously through the synergistic effect between the various steps. The use of a benzene-free synthesis process and a benzene-free catalyst makes the process more environmentally friendly and safe, achieving "benzene-free" and a simpler process. The input of acetylene is reduced, the raw material ratio is precise, the generation of high-boiling substances is reduced, and the effects of energy conservation and environmental protection are achieved. In addition, the purity of methylvinyldichlorosilane is improved, the content of major reaction by-products is reduced, and the yield is also improved. The purity of methylvinyldichlorosilane is 98.1-99.8wt%, the content of major reaction by-products is 0.1-1.7wt%, and the yield of methylvinyldichlorosilane is 97.0-98.7wt%.

[0008] In the prior art, when methylvinyldichlorosilane is synthesized by acetylene and methyldichlorosilane, toluene is used as a solvent, and an excessive amount of acetylene needs to be added. Moreover, the reaction process is carried out at intervals, which affects the mass transfer efficiency. In the present application, acetylene and monomethyldichlorosilane are used as a solvent under the action of hexahydrate chloroplatinic acid catalyst, and after heating and pressurization, an addition reaction is carried out to obtain methylvinyldichlorosilane, so that the content of acetylene is slightly excessive, and the reaction is carried out continuously, thereby reducing the input of acetylene, thereby accurately proportioning the raw materials, reducing the generation of high-boiling substances, thereby achieving the effect of energy saving and environmental protection, realizing "benzenization-free", and also improving the purity and product yield.

[0009] Preferably, the catalyst is prepared by modifying chloroplatinic acid hexahydrate with 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane.

[0010] Preferably, the modified catalyst is prepared by the following method: placing chloroplatinic acid hexahydrate and 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane in anhydrous ethanol, adding isopropanol, mixing evenly, refluxing under nitrogen protection, standing, filtering solids, washing solids, and drying to obtain the modified catalyst.

[0011] Furthermore, the modified catalyst is prepared by the following method: placing chloroplatinic acid hexahydrate and 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane in anhydrous ethanol, adding isopropanol, mixing evenly, refluxing for 0.5-1.5 hours under nitrogen protection, standing for 10-14 hours, filtering the solid, washing the solid 3-5 times with an ethanol solution, and drying to obtain the modified catalyst;

[0012] The amount of anhydrous ethanol added to 1g of chloroplatinic acid hexahydrate is 6-8mL, the weight ratio of chloroplatinic acid hexahydrate to isopropanol is 1:(3-5), and the mass fraction of the ethanol solution is 70-80%.

[0013] By adopting the above technical solution, 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane is used to modify chloroplatinic acid hexahydrate to obtain a modified catalyst. This modified catalyst can exhibit better catalytic activity and is much better than the catalytic effect of chloroplatinic acid hexahydrate catalyst. In addition, the modified catalyst has significant characteristics such as strong selectivity and low catalyst usage. It has very high industrial application value. When applied to the synthesis process of methylvinyldichlorosilane, it can more easily prepare methylvinyldichlorosilane and increase the yield of methylvinyldichlorosilane.

[0014] Preferably, the weight ratio of the chloroplatinic acid hexahydrate to 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane is 1:(3-5).

[0015] If the amount of 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane added is too small, it cannot react optimally with chloroplatinic acid hexahydrate, resulting in low activity of the modified catalyst; if the amount of 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane added is too large, it will cause waste of raw materials and lead to high production costs. By adopting the above technical solution, when the weight ratio of chloroplatinic acid hexahydrate and 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane is within the above range, not only can raw materials be saved and production costs be reduced, but also a modified catalyst with better catalytic activity can be produced, which is more conducive to improving the yield of methylvinyldichlorosilane.

[0016] Preferably, the 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane is pretreated by the following method before use: 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane is soaked in anhydrous sodium sulfate, distilled under reduced pressure, and the fractions are collected to obtain pretreated 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane.

[0017] Furthermore, the 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane is pretreated by the following method before use: 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane is soaked in anhydrous sodium sulfate for 40-56 hours, distilled under reduced pressure, and the fraction between 120-130° C. is collected to obtain pretreated 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane;

[0018] The amount of anhydrous sodium sulfate added to each 1 g of 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane is 5-7 mL.

[0019] By adopting the above technical solution, 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane is pretreated with anhydrous sodium sulfate, which can reduce the influence of other impurities in 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, facilitate the better modification of chloroplatinic acid hexahydrate by 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, thereby facilitating the preparation of the modified catalyst and improving the yield of methylvinyldichlorosilane.

[0020] Preferably, the weight ratio of monomethyldichlorosilane to acetylene is 1:(0.3-0.4).

[0021] By adopting the above technical solution, acetylene is used in a slightly excessive amount in the synthesis process of methylvinyldichlorosilane, which not only saves resources, reduces costs, and accurately proportions raw materials, but also realizes continuous production and reduces the generation of high-boiling substances, thereby achieving energy-saving and environmental protection effects, and can also improve the mass transfer efficiency and yield of methylvinyldichlorosilane.

[0022] Preferably, the added amount of the catalyst is 0.01-0.03 wt% of monomethyldichlorosilane.

[0023] By adopting the above technical solution, the amount of catalyst added is limited, so that the catalyst can better exert its catalytic activity and better synthesize methylvinyldichlorosilane, thereby improving production efficiency.

[0024] Preferably, the reaction temperature is 30-95° C., and the reaction time is 30-40 s.

[0025] Preferably, the reaction pressure is 0.12-0.36 MPa.

[0026] By adopting the above technical solution, the reaction temperature, reaction time and reaction pressure in the synthesis process of methylvinyldichlorosilane are limited. By controlling the reaction temperature and reaction pressure, continuous production is achieved, the generation of high-boiling substances is reduced, energy saving and environmental protection are achieved, and the purity and yield of methylvinyldichlorosilane can be improved.

[0027] In summary, this application includes at least one of the following beneficial technical effects:

[0028] 1. In the present application, monomethyldichlorosilane and a slightly excess of acetylene are reacted in the presence of a hexahydrate chloroplatinic acid catalyst, with methylvinyldichlorosilane as a solvent, and the temperature and pressure are increased to carry out an addition reaction to prepare methylvinyldichlorosilane. This allows the reaction to proceed continuously, reduces the input of acetylene, accurately proportions the raw materials, reduces the generation of high-boiling substances, thereby achieving energy conservation and environmental protection, achieving "benzenization-free", and improving the purity and yield of methylvinyldichlorosilane. The purity of methylvinyldichlorosilane can reach 99.8wt%, the content of major reaction by-products is reduced to 0.1wt%, and the yield of methylvinyldichlorosilane reaches 98.7wt%.

[0029] 2. In the present application, 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane is preferably used to modify chloroplatinic acid hexahydrate to obtain a modified catalyst. The modified catalyst has significant characteristics such as strong selectivity and low catalyst usage, and has very high industrial application value. When applied to the synthesis process of methylvinyldichlorosilane, it can facilitate the preparation of methylvinyldichlorosilane and improve the yield of methylvinyldichlorosilane. DETAILED DESCRIPTION

[0030] The following is a further detailed description of this application in conjunction with the specific content.

[0031] Preparation Example

[0032] Preparation Example 1

[0033] A modified catalyst is prepared by the following method:

[0034] 2 kg of chloroplatinic acid hexahydrate and 6 kg of 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane were placed in 14 L of anhydrous ethanol, 4 kg of isopropanol was added, and the mixture was evenly mixed. Under nitrogen protection, the mixture was refluxed for 1.0 h, allowed to stand for 12 h, the solid was filtered, and the solid was washed 5 times with a 75% mass fraction ethanol solution, and dried to obtain a modified catalyst.

[0035] Preparation Example 2

[0036] A modified catalyst is disclosed, which differs from Preparation Example 1 in that the amount of 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane added is different. The amount of 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane added in Preparation Example 2 is 8 kg.

[0037] Preparation Example 3

[0038] A modified catalyst is disclosed, which differs from Preparation Example 1 in that the amount of 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane added is different. The amount of 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane added in Preparation Example 3 is 10 kg.

[0039] Example

[0040] Example 1

[0041] A synthesis process for methylvinyldichlorosilane comprises the following steps:

[0042] 2 kg of monomethyldichlorosilane was gasified at 42 ° C, added to 10 L of methylvinyldichlorosilane, and 0.6 kg of acetylene was added. Under the action of 0.0002 kg of hexahydrate chloroplatinic acid catalyst, the reaction was carried out at 30 ° C and 0.12 MPa for 35 seconds, and then distilled and separated at 115 ° C to obtain methylvinyldichlorosilane.

[0043] Example 2

[0044] A synthesis process of methylvinyldichlorosilane, which differs from Example 1 in that the type of catalyst is different. The catalyst is the modified catalyst prepared by Preparation Example 1.

[0045] Example 3

[0046] A synthesis process of methylvinyldichlorosilane, which differs from Example 1 in that the type of catalyst is different. The catalyst is the modified catalyst prepared by Preparation Example 2.

[0047] Example 4

[0048] A synthesis process of methylvinyldichlorosilane, which differs from Example 1 in that the type of catalyst is different. The catalyst is the modified catalyst prepared by Preparation Example 3.

[0049] Example 5

[0050] A synthesis process of methylvinyldichlorosilane is disclosed. The difference between the synthesis process and Example 3 is that 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane in the modified catalyst is pretreated by the following method before use: 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane is soaked in anhydrous sodium sulfate for 48 hours, subjected to reduced pressure distillation, and fractions at 125° C. are collected to obtain pretreated 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane; wherein the amount of anhydrous sodium sulfate added to 1 g of 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane is 6 mL.

[0051] Example 6

[0052] A synthesis process of methylvinyldichlorosilane, which differs from Example 5 in that the amount of acetylene added is different. The amount of acetylene added in Example 6 is 0.7 kg.

[0053] Example 7

[0054] A synthesis process of methylvinyldichlorosilane, which differs from Example 5 in that the amount of acetylene added is different. The amount of acetylene added in Example 7 is 0.8 kg.

[0055] Example 8

[0056] A synthesis process for methylvinyldichlorosilane, which differs from Example 6 in that the amount of catalyst added is different. The amount of catalyst added in Example 8 is 0.0004 kg.

[0057] Example 9

[0058] A synthesis process for methylvinyldichlorosilane, which differs from Example 6 in that the amount of catalyst added is different. The amount of catalyst added in Example 9 is 0.0006 kg.

[0059] Example 10

[0060] A synthesis process of methylvinyldichlorosilane, which differs from Example 8 in that the reaction temperature is different. The reaction temperature in Example 10 is 80°C.

[0061] Example 11

[0062] A synthesis process of methylvinyldichlorosilane, which differs from Example 8 in that the reaction temperature is different. The reaction temperature in Example 11 is 95°C.

[0063] Example 12

[0064] A synthesis process for methylvinyldichlorosilane, which differs from Example 10 in that the reaction pressure is different. The pressure in Example 12 is 0.28 MPa.

[0065] Example 13

[0066] A synthesis process for methylvinyldichlorosilane, which differs from Example 10 in that the reaction pressure is different. The pressure in Example 13 is 0.36 MPa.

[0067] Comparative Example

[0068] Comparative Example 1

[0069] A synthesis process for methylvinyldichlorosilane comprises the following steps:

[0070] 2 kg of monomethyldichlorosilane was heated and vaporized, 10 L of toluene and 2 kg of acetylene were added, and after mixing evenly, the temperature was maintained at 60 ° C and the pressure was maintained at 0.8 MPa, and the reaction was carried out for 5 hours. Then, the mixture was distilled and separated at a temperature of 90 ° C to obtain methylvinyldichlorosilane.

[0071] Performance testing

[0072] The following performance tests were performed on the methylvinyldichlorosilane in Examples 1-13 and Comparative Example 1:

[0073] Purity: The purity of the prepared methylvinyldichlorosilane was measured, and the test results are shown in Table 1.

[0074] Content of main reaction by-products: The content of main reaction by-products was measured, and the test results are shown in Table 1.

[0075] Yield: The yield of methylvinyldichlorosilane was measured, and the test results are shown in Table 1.

[0076] Table 1 Test results

[0077]

[0078]

[0079] As can be seen from Table 1, the synthesis process of methylvinyldichlorosilane of the present application, through the synergistic effect between the steps, allows the reaction to proceed continuously, reduces the input of acetylene, accurately adjusts the raw material ratio, reduces the generation of high-boiling substances, achieves the effect of energy saving and environmental protection, realizes "benzenization-free", and not only improves the purity of methylvinyldichlorosilane, reduces the content of major reaction by-products, but also improves the yield. Among them, the purity of methylvinyldichlorosilane is 98.1-99.8wt%, the content of major reaction by-products is 0.1-1.7wt%, and the yield of methylvinyldichlorosilane is 97.0-98.7wt%.

[0080] Combining Example 1 and Comparative Example 1, it can be seen that the purity of methylvinyldichlorosilane in Example 1 is 98.1wt%, the content of main reaction by-products is 1.7wt%, and the yield of methylvinyldichlorosilane is 97.0wt%, which is better than Comparative Example 1, indicating that the synthesis process of methylvinyldichlorosilane in Example 1 is more suitable, reduces the input of acetylene, accurately proportions the raw materials, and achieves "benzene-free", which not only improves the purity of methylvinyldichlorosilane, reduces the content of main reaction by-products, but also improves the yield of methylvinyldichlorosilane.

[0081] In combination with Examples 1-4, it can be seen that the purity of methylvinyldichlorosilane in Example 3 is 98.4wt%, the content of main reaction by-products is 1.3wt%, and the yield of methylvinyldichlorosilane is 97.3wt%, which is better than other examples, indicating that it is more appropriate to use a modified catalyst in the synthesis process of methylvinyldichlorosilane, and the modified catalyst prepared in Preparation Example 2 is more appropriate. The modified catalyst has the advantages of high selectivity and high catalytic activity, thereby realizing continuous production, achieving energy-saving and environmental protection effects, realizing "benzene-free", and also improving the purity of methylvinyldichlorosilane, reducing the content of main reaction by-products, and improving the yield of methylvinyldichlorosilane.

[0082] Combining Example 3 and Example 5, it can be seen that the purity of methylvinyldichlorosilane in Example 5 is 98.5wt%, the content of main reaction by-products is 1.1wt%, and the yield of methylvinyldichlorosilane is 97.4wt%, which is better than Example 3, indicating that it is more appropriate to use a modified catalyst in the synthesis process of methylvinyldichlorosilane, and it is more appropriate to pretreat the 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane in the modified catalyst before use, so that the modified catalyst can better play a role, not only improving the purity of methylvinyldichlorosilane, reducing the content of main reaction by-products, but also improving the yield of methylvinyldichlorosilane.

[0083] In combination with Examples 5-7, it can be seen that the purity of methylvinyldichlorosilane in Example 6 is 98.9wt%, the content of main reaction by-products is 0.8wt%, and the yield of methylvinyldichlorosilane is 97.8wt%, which is better than other embodiments, indicating that the amount of acetylene added in Example 6 is more appropriate, not only reducing the input of acetylene and achieving continuous production reaction, but also accurately proportioning raw materials, reducing the generation of high boiling points, achieving energy saving and environmental protection effects, achieving "benzene-free", and also improving the purity of methylvinyldichlorosilane, reducing the content of main reaction by-products, and improving the yield of methylvinyldichlorosilane.

[0084] In combination with Example 6 and Examples 8-9, it can be seen that the purity of methylvinyldichlorosilane in Example 8 is 99.2wt%, the content of the main reaction by-products is 0.5wt%, and the yield of methylvinyldichlorosilane is 98.1wt%, which is better than other examples, indicating that the amount of catalyst added in Example 8 is more appropriate, improves the purity of methylvinyldichlorosilane, reduces the content of the main reaction by-products, and also improves the yield of methylvinyldichlorosilane.

[0085] In combination with Example 8 and Examples 10-11, it can be seen that the purity of methylvinyldichlorosilane in Example 10 is 99.6wt%, the content of the main reaction by-products is 0.3wt%, and the yield of methylvinyldichlorosilane is 98.5wt%, which is better than other examples, indicating that the reaction temperature in Example 10 is more suitable, can ensure continuous reaction, improve the purity of methylvinyldichlorosilane, reduce the content of the main reaction by-products, and also improve the yield of methylvinyldichlorosilane.

[0086] In combination with Example 10 and Examples 12-13, it can be seen that the purity of methylvinyldichlorosilane in Example 12 is 99.8wt%, the content of the main reaction by-products is 0.1wt%, and the yield of methylvinyldichlorosilane is 98.7wt%, which is better than other examples, indicating that the reaction pressure in Example 12 is more appropriate, which is conducive to the continuous reaction, achieves "benzenization-free", improves the purity of methylvinyldichlorosilane, reduces the content of the main reaction by-products, and also improves the yield of methylvinyldichlorosilane.

[0087] The above-mentioned specific implementation examples are all preferred embodiments of the present application and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A synthesis process for methylvinyldichlorosilane, characterized in that: The method comprises the following steps: adding acetylene and vaporized monomethyldichlorosilane to methylvinyldichlorosilane, wherein the weight ratio of monomethyldichlorosilane to acetylene is 1:(0.3-0.4); heating and pressurizing the mixture under the action of hexahydrate chloroplatinic acid catalyst, reacting for a period of time, and performing rectification and separation to obtain methylvinyldichlorosilane; The catalyst is prepared by modifying chloroplatinic acid hexahydrate with 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, wherein the weight ratio of chloroplatinic acid hexahydrate to 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane is 1:(3-5); and the added amount of the catalyst is 0.01-0.03 wt% of monomethyldichlorosilane.

2. A synthesis process for methylvinyldichlorosilane according to claim 1, characterized in that: The modified catalyst is prepared by the following method: placing chloroplatinic acid hexahydrate and 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane in anhydrous ethanol, adding isopropanol, mixing uniformly, refluxing under nitrogen protection, standing, filtering solids, washing the solids, and drying to obtain the modified catalyst.

3. A process for synthesizing methylvinyldichlorosilane according to claim 1, characterized in that: The 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane is pretreated by the following method before use: 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane is soaked in anhydrous sodium sulfate, distilled under reduced pressure, and fractions are collected to obtain pretreated 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane.

4. A process for synthesizing methylvinyldichlorosilane according to claim 1, characterized in that: The reaction temperature is 30-95° C., and the reaction time is 30-40 seconds.

5. A process for synthesizing methylvinyldichlorosilane according to claim 1, characterized in that: The reaction pressure is 0.12-0.36 MPa.

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