Green synthesis method of electronic-grade methylsilane and hydrogen chloride based on ionic liquid catalyst

Abstract

The invention discloses a green synthesis method of electronic-grade methylsilane and hydrogen chloride based on an ionic liquid catalyst, belongs to the technical field of synthesis of organosilicon compounds and high-purity electronic special gases, and discloses a green synthesis method of electronic-grade methylsilane and hydrogen chloride based on an ionic liquid catalyst. Comprising the following steps of S1, catalyst preparation, S2, methylsilane and hydrogen chloride preparation, S3, product purification and S4, activated carbon regeneration, 1-ethyl-3-methylimidazole aluminum chloride as the catalyst has good thermal stability and catalytic activity, the risk of catalyst inactivation is avoided, the catalyst can be pumped into a reaction kettle, the whole process is operated in a closed mode, and operation is easy. The method is safe, reliable and environment-friendly, and meanwhile, regeneration and recycling of the activated carbon bring a better use prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of organic silicon compounds and high-purity electronic special gas synthesis, in particular to a green synthesis method of electronic-grade methylsilane and hydrogen chloride based on an ionic liquid catalyst. BACKGROUND

[0002] The synthesis of organic silicon compounds and high-purity electronic special gases plays a crucial role in modern industry and scientific research, especially in the fields of semiconductor manufacturing, electronic device packaging, biomedicine, and aerospace. Electronic special gases refer to high-purity gases used in semiconductor manufacturing and other high-tech industries, such as silane (SiH4), phosphine (PH3), arsine (AsH3), and borane (B2H6). These gases are used in processes such as thin film deposition, doping, etching, and cleaning.

[0003] In the prior art, the synthesis of methylsilane usually uses active metal hydride solid reducing agents and catalysts. During the process of reducing agent / catalyst being put into the reactor, the reducing agent / catalyst immediately reacts with moisture in the air to produce hydrogen gas, which poses a safety risk of flammability and explosion, and also causes the reducing agent / catalyst to be easily deactivated, affecting product quality. At the same time, hydrogen chloride as a byproduct is usually not effectively purified and utilized, causing environmental pollution. Therefore, we propose a green synthesis method of electronic-grade methylsilane and hydrogen chloride based on an ionic liquid catalyst. SUMMARY

[0004] The purpose of the present application is to provide a green synthesis method of electronic-grade methylsilane and hydrogen chloride based on an ionic liquid catalyst, which can effectively solve the problems raised in the background art.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present application is as follows: a green synthesis method of electronic-grade methylsilane and hydrogen chloride based on an ionic liquid catalyst, the preparation method of the electronic-grade methylsilane and hydrogen chloride is as follows:

[0006] S1. Preparation of catalyst: 1-ethyl-3-methylimidazole is added to the reaction container of the electric stirring heater, the stirring speed of the electric stirring heater is set to 50-70 rpm, and then an equal molar amount of aluminum chloride is slowly added to the container. The stirring speed of the electric stirring heater is set to 200-400 rpm, and the stirring time is 5-10 min to ensure uniform mixing of 1-ethyl-3-methylimidazole and aluminum chloride. The reaction temperature of the electric stirring heater is set to 60-80℃, and the reaction time is set to 2h. After sufficient reaction, the ionic liquid catalyst 1-ethyl-3-methylimidazole aluminum chloride is prepared;

[0007] S2. Preparation of methylsilane and hydrogen chloride: keep the high-pressure reactor dry, preheat the reactor, set the preheating time to 10-30 min, set the preheating temperature to 60-80°C, after the high-pressure reactor gas inlet is connected with nitrogen, the methylchlorosilane mixture and the ionic liquid catalyst 1-ethyl-3-methylimidazolium aluminum chloride prepared in S1 are added into the high-pressure reactor in sequence, hydrogen is slowly introduced from the gas inlet valve of the high-pressure reactor, the pressure is maintained at 0.01-20 atm, and the temperature is set to 10-350°C to produce a mixture of methylsilane and hydrogen chloride;

[0008] S3. Purification of the product: the mixture of methylsilane and hydrogen chloride generated in S2 is sent to a cooler for preliminary cooling, the cooling temperature is -40°C to -60°C, and the cooling time is 5-10 min, the boiling point of methylsilane is -22.3°C at standard atmospheric pressure, and the methylsilane is liquefied, the boiling point of hydrogen chloride is -84.9°C at standard atmospheric pressure, and the hydrogen chloride remains gaseous, the methylsilane is guided out from the bottom of the cooler by gravity or pumping and collected into a dewar flask, the separated methylsilane is introduced into an adsorption tower, and the remaining gas is further captured after the methylsilane is removed by a cold trap, and the hydrogen chloride is collected by rectification.

[0009] S4. Regeneration of activated carbon: the regenerator is filled with nitrogen, the internal temperature of the regenerator is set to 150-170°C, the heated nitrogen in the regenerator is introduced into the adsorption tower, and the adsorption tower is replaced with hot nitrogen for 50-80 min. Then, the adsorption tower is connected with a vacuum pump, and the internal pressure is maintained at -0.095 atm for 110-130 min.

[0010] As preferred, the molar ratio of 1-ethyl-3-methylimidazole to aluminum chloride in S1 is 1:1.

[0011] As preferred, the methylchlorosilane mixture in S2 is one, two or three of methyltrichlorosilane, methyldichlorosilane and methylchlorosilane in a molar ratio of 1:1:1 to 0.01-10:0.01-10:0.01-10.

[0012] As preferred, the molar ratio of the methylchlorosilane mixture to hydrogen in S2 is 1-10.

[0013] As preferred, when the methylsilane is purified and collected in the S3, the separated methylsilane is introduced into an adsorption tower, the temperature is set to -78 DEG C, activated carbon is selected as the adsorbent to remove nitrogen, carbon monoxide, carbon dioxide, chlorosilane, silane and other impurities, then the methylsilane is introduced into a rectifying tower, the pressure in the tower is set to 0.1-1 atm, the top temperature is set to -20 DEG C to -30 DEG C, the bottom temperature is set to -10 DEG C to 0 DEG C, the separated methylsilane gas in the adsorption tower is preheated to -20 DEG C to -25 DEG C, and then is introduced into the lower part of the rectifying tower for rectification, the methylsilane is evaporated from the top as a lighter component, and the impurities are left in the bottom or are taken out from the middle part, the methylsilane vapor at the top is condensed into liquid by a condenser, and is collected by a low-temperature storage tank.

[0014] As preferred, after the methylsilane is liquefied, the remaining gas is captured again, and the methylsilane possibly existing in the remaining gas is discharged, a deep cooling trap is installed after the cooler, the working temperature of the trap is -60 DEG C to -80 DEG C, and any uncondensed methylsilane is captured.

[0015] As preferred, the hydrogen chloride is purified and collected, after the methylsilane is captured again, the remaining hydrogen chloride in the cooler is mainly gaseous, the hydrogen chloride is discharged from the cooler, the cooler is heated, the hydrogen chloride gas is discharged from the cooler, enters a rectifying tower, the pressure in the tower is set to 0.01-10 atm, and the temperature is set to -50 DEG C to 100 DEG C, secondary rectification purification is carried out, the purity reaches the electronic grade, the hydrogen chloride vapor at the top of the rectifying tower is condensed into liquid by a condenser, and is collected by a Dewar flask.

[0016] Compared with the prior art, the present application provides a green synthesis method of electronic grade methylsilane and hydrogen chloride based on an ionic liquid catalyst, and has the following beneficial effects:

[0017] 1. The method for green synthesis of electronic grade methylsilane and hydrogen chloride based on ionic liquid catalyst, nitrogen is introduced into the reaction kettle before reaction to avoid the risk of explosion or fire, and 1-ethyl-3-methylimidazole aluminum chloride is used as the catalyst, which has good thermal stability and catalytic activity, the catalyst in the prior art is prone to react with moisture in the air, resulting in catalyst deactivation, ultimately reducing the yield and output of the product, the use of 1-ethyl-3-methylimidazole aluminum chloride as the catalyst can avoid the above situation, since 1-ethyl-3-methylimidazole aluminum chloride has good thermal stability, 1-ethyl-3-methylimidazole aluminum chloride will not react with water or other substances in the air, and the purification of the product becomes simple, and since 1-ethyl-3-methylimidazole aluminum chloride has good catalytic activity, the overall synthesis reaction occurs relatively quickly, and 1-ethyl-3-methylimidazole aluminum chloride can be pumped into the reaction kettle, the whole process is closed operation, the human body is not harmed, and it is safe, reliable, and environmentally friendly.

[0018] 2. The method for green synthesis of electronic grade methylsilane and hydrogen chloride based on ionic liquid catalyst, the adsorption-saturated activated carbon is heated to 150 DEG C under an inert gas atmosphere for 1 h, and then kept at -0.095 atm vacuum, so as to realize the regeneration and recycling of the activated carbon, the regeneration of the activated carbon reduces the dependence on natural resources and reduces the impact on the environment, because there is no need to frequently mine and manufacture new activated carbon, in addition, the problem of a large amount of waste activated carbon is avoided, and potential environmental pollution is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 The preparation flow chart of the ionic liquid catalyst 1-ethyl-3-methylimidazole aluminum chloride;

[0020] Figure 2 The synthesis reaction flow chart of the method for green synthesis of electronic grade methylsilane and hydrogen chloride based on ionic liquid catalyst;

[0021] Figure 3 The purification flow chart of methylsilane and hydrogen chloride;

[0022] Figure 4 The regeneration flow chart of activated carbon. DETAILED DESCRIPTION

[0023] In order to make the technical means, creative features, purposes and effects of the present application easy to understand, the present application will be further described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0024] In order to overcome the shortcomings of the prior art, the present application provides a green synthesis method of electronic-grade methylsilane and hydrogen chloride based on an ionic liquid catalyst.

[0025] S1. Preparation of the catalyst: 1-ethyl-3-methylimidazole is added to the reaction container of the electrically stirred heater, the rotation speed of the electrically stirred heater is set to 50-70 rpm, and then equal molar amounts of aluminum chloride are slowly added to the container. The rotation speed of the electrically stirred heater is set to 200-400 rpm, and the stirring time is 5-10 min to ensure uniform mixing of 1-ethyl-3-methylimidazole and aluminum chloride. The molar ratio of 1-ethyl-3-methylimidazole to aluminum chloride is 1:1. The reaction temperature of the electrically stirred heater is set to 60-80°C, and the reaction time is set to 2 h. After sufficient reaction, the ionic liquid catalyst 1-ethyl-3-methylimidazole aluminum chloride is prepared.

[0026] S2. Preparation of methylsilane and hydrogen chloride: Keep the high-pressure reactor dry, preheat the reactor, set the preheating time to 10-30 min, and the preheating temperature to 60-80°C. After passing nitrogen through the gas inlet of the high-pressure reactor, the ionic liquid catalyst 1-ethyl-3-methylimidazole aluminum chloride prepared in S1 is added through the feed inlet of the high-pressure reactor in sequence. The methylchlorosilane mixture is one, two or three of methyltrichlorosilane, methyldichlorosilane and methylmonochlorosilane in a molar ratio of 1:1:1 to 0.01-10:0.01-10:0.01-10. Hydrogen is slowly passed from the gas inlet valve dedicated to the high-pressure reactor, and the molar ratio of the methylchlorosilane mixture to hydrogen is 1-10. The pressure is maintained at 0.01-20 atm, and the temperature is set to 10-350°C to produce a mixture of methylsilane and hydrogen chloride.

[0027] S3. Purification of the product: The mixture of methylsilane and hydrogen chloride generated in the reaction in S2 is sent to a cooler for preliminary cooling, the cooling temperature is -40 to -60°C, the cooling time is 5-10 min, the boiling point of methylsilane is -22.3°C at standard atmospheric pressure, and the methylsilane is liquefied, the boiling point of hydrogen chloride is -84.9°C at standard atmospheric pressure, and the hydrogen chloride remains gaseous, the methylsilane is guided out from the bottom of the cooler by gravity or pumping and collected in a dewar flask, the separated methylsilane is sent to an adsorption tower, the temperature is set to -78°C, activated carbon is selected as the adsorbent to remove nitrogen, carbon monoxide, carbon dioxide, chlorosilane, silane and other impurities, and then the methylsilane is sent to a rectification tower, the tower pressure is set to 0.1 to 1 atm, the top temperature is set to -20 to -30°C, and the bottom temperature is set to -10 to 0°C, the separated methylsilane gas in the adsorption tower is preheated to -20 to -25°C and then sent to the lower part of the rectification tower for rectification (one standby), the methylsilane as the lighter component is distilled from the top of the tower, and the impurities as the heavier component remain in the bottom or are taken out from the middle, the methylsilane vapor at the top is condensed into liquid by a condenser and collected by a low-temperature storage tank, the methylsilane is liquefied, and the remaining gas is captured again to remove the methylsilane that may exist in the remaining gas, a deep cold trap is installed behind the cooler, the working temperature of the cold trap is -60 to -80°C, and any uncondensed methylsilane is captured, hydrogen chloride is collected by rectification, and the hydrogen chloride is purified and collected, after the methylsilane is captured again, the remaining hydrogen chloride in the cooler is mainly gaseous, the hydrogen chloride is discharged from the cooler, the cooler is heated, the hydrogen chloride gas is discharged from the cooler, enters the rectification tower, the tower pressure is set to 0.01-10 atm, and the temperature is set to -50 to 100°C, and the hydrogen chloride is purified by secondary rectification to reach the electronic grade purity, and the hydrogen chloride vapor at the top of the rectification tower is condensed into liquid by a condenser and collected by a dewar flask.

[0028] S4. Regeneration of activated carbon: The regenerator is filled with nitrogen, the internal temperature of the regenerator is set to 150-170°C, and the heated nitrogen in the regenerator is sent to the adsorption tower, the adsorption tower is replaced with hot nitrogen for 50-80 min. Then, the adsorption tower is connected to a vacuum pump, and the internal pressure is maintained at -0.095 atm for 110-130 min.

[0029] It should be noted that this invention is a green synthesis method for electronic-grade methylsilane and hydrogen chloride based on an ionic liquid catalyst. 1-Ethyl-3-methylimidazolium aluminum chloride [EMIM][AlCl4] is selected as the catalyst, exhibiting good thermal stability and catalytic activity. Furthermore, the catalyst can be pumped into the reactor, and the entire process is a closed operation, ensuring safety, reliability, and environmental friendliness, as it is harmless to humans. One, two, or three of methyltrichlorosilane (MeSiCl3), methyldichlorosilane (MeSiHCl2), and methylmonochlorosilane (MeSiH2Cl) are used as raw materials in a ratio of 1:1:1 to 0.01-10:0.01-10:0.01-10. This fully utilizes the ionic and molecular interactions between the raw materials, achieving higher reactivity and selectivity, and ensuring controllable ratios of electronic-grade methylsilane and hydrogen chloride with minimal cost.

[0030] Example 1

[0031] A green method for the electronic-grade synthesis of methylsilane and hydrogen chloride based on an ionic liquid catalyst includes the following steps:

[0032] S1. Preparation of catalyst: 1-Ethyl-3-methylimidazolium was added to a reaction vessel with an electric stirrer. The speed of the electric stirrer was set to 50-70 rpm. An equimolar amount of aluminum chloride was slowly added to the vessel. The speed of the electric stirrer was then set to 200 rpm and the stirring time was 5 min to ensure uniform mixing of 1-ethyl-3-methylimidazolium and aluminum chloride. The reaction temperature of the electric stirrer was set to 60-80℃ and the reaction time was set to 2 h. After the reaction was complete, the ionic liquid catalyst 1-ethyl-3-methylimidazolium aluminum chloride was obtained.

[0033] S2. Preparation of methylsilane and hydrogen chloride: Keep the high-pressure reactor dry, preheat the reactor for 10-30 min, and set the preheating temperature to 60-80℃. After introducing nitrogen into the gas inlet of the high-pressure reactor, add the methylchlorosilane mixture and the ionic liquid catalyst 1-ethyl-3-methylimidazolium aluminum chloride prepared in S1 sequentially through the feed inlet of the high-pressure reactor. Slowly introduce hydrogen from the gas inlet valve of the high-pressure reactor, maintain the pressure at 0.01-20 atm, and set the temperature at 10-350℃ to produce a mixed gas of methylsilane and hydrogen chloride.

[0034] S3. Purification of the product: The mixed gas of methylsilane and hydrogen chloride generated in S2 above is sent to a cooler for preliminary cooling at a temperature of -40℃ to -60℃ for 5-10 minutes. The boiling point of methylsilane is -22.3℃ under standard atmospheric pressure. The methylsilane is liquefied. The boiling point of hydrogen chloride is -84.9℃ under standard atmospheric pressure. The hydrogen chloride remains in a gaseous state. The methylsilane is discharged from the bottom of the cooler by gravity or pump and collected in a Dewar flask. The separated methylsilane is passed into an adsorption tower and adsorbed by activated carbon before being distilled. The remaining gas is further purified by capturing methylsilane in a cold trap and then distilled to collect hydrogen chloride.

[0035] S4. Regeneration of activated carbon: The regeneration furnace is filled with nitrogen gas, and the internal temperature of the regeneration furnace is set to 150℃-170℃. The nitrogen gas heated in the regeneration furnace is introduced into the adsorption tower, and the hot nitrogen replacement time in the adsorption tower is 50-80 minutes. Afterwards, the adsorption tower is connected to a vacuum pump, and the internal temperature is maintained at -0.095 atm for 110-130 minutes.

[0036] Example 2

[0037] A green method for the electronic-grade synthesis of methylsilane and hydrogen chloride based on an ionic liquid catalyst includes the following steps:

[0038] S1. Preparation of catalyst: 1-Ethyl-3-methylimidazolium was added to a reaction vessel with an electric stirrer. The speed of the electric stirrer was set to 50-70 rpm. An equimolar amount of aluminum chloride was slowly added to the vessel. The speed of the electric stirrer was then set to 300 rpm and the stirring time was 8 min to ensure uniform mixing of 1-ethyl-3-methylimidazolium and aluminum chloride. The reaction temperature of the electric stirrer was set to 60-80℃ and the reaction time was set to 2 h. After the reaction was complete, the ionic liquid catalyst 1-ethyl-3-methylimidazolium aluminum chloride was obtained.

[0039] S2. Preparation of methylsilane and hydrogen chloride: Keep the high-pressure reactor dry, preheat the reactor for 10-30 min, and set the preheating temperature to 60-80℃. After introducing nitrogen into the gas inlet of the high-pressure reactor, add the methylchlorosilane mixture and the ionic liquid catalyst 1-ethyl-3-methylimidazolium aluminum chloride prepared in S1 sequentially through the feed inlet of the high-pressure reactor. Slowly introduce hydrogen from the gas inlet valve of the high-pressure reactor, maintain the pressure at 0.01-20 atm, and set the temperature at 10-350℃ to produce a mixed gas of methylsilane and hydrogen chloride.

[0040] S3. Purification of the product: The mixed gas of methylsilane and hydrogen chloride generated in S2 above is sent to a cooler for preliminary cooling at a temperature of -40℃ to -60℃ for 5-10 minutes. The boiling point of methylsilane is -22.3℃ under standard atmospheric pressure. The methylsilane is liquefied. The boiling point of hydrogen chloride is -84.9℃ under standard atmospheric pressure. The hydrogen chloride remains in a gaseous state. The methylsilane is discharged from the bottom of the cooler by gravity or pump and collected in a Dewar flask. The separated methylsilane is passed into an adsorption tower and adsorbed by activated carbon before being distilled. The remaining gas is further purified by capturing methylsilane in a cold trap and then distilled to collect hydrogen chloride.

[0041] S4. Regeneration of activated carbon: The regeneration furnace is filled with nitrogen gas, and the internal temperature of the regeneration furnace is set to 150℃-170℃. The nitrogen gas heated in the regeneration furnace is introduced into the adsorption tower, and the hot nitrogen replacement time in the adsorption tower is 50-80 minutes. Afterwards, the adsorption tower is connected to a vacuum pump, and the internal temperature is maintained at -0.095 atm for 110-130 minutes.

[0042] Example 3

[0043] A green method for the electronic-grade synthesis of methylsilane and hydrogen chloride based on an ionic liquid catalyst includes the following steps:

[0044] S1. Preparation of catalyst: 1-Ethyl-3-methylimidazolium was added to a reaction vessel with an electric stirrer. The electric stirrer was set to a speed of 50-70 rpm. An equimolar amount of aluminum chloride was slowly added to the vessel. The electric stirrer was then set to a speed of 400 rpm and a stirring time of 10 min to ensure uniform mixing of 1-ethyl-3-methylimidazolium and aluminum chloride. The reaction temperature of the electric stirrer was set to 60-80℃ and the reaction time was set to 2 h. After the reaction was complete, the ionic liquid catalyst 1-ethyl-3-methylimidazolium aluminum chloride was obtained.

[0045] S2. Preparation of methylsilane and hydrogen chloride: Keep the high-pressure reactor dry, preheat the reactor for 10-30 min, and set the preheating temperature to 60-80℃. After introducing nitrogen into the gas inlet of the high-pressure reactor, add the methylchlorosilane mixture and the ionic liquid catalyst 1-ethyl-3-methylimidazolium aluminum chloride prepared in S1 sequentially through the feed inlet of the high-pressure reactor. Slowly introduce hydrogen from the gas inlet valve of the high-pressure reactor, maintain the pressure at 0.01-20 atm, and set the temperature at 10-350℃ to produce a mixed gas of methylsilane and hydrogen chloride.

[0046] S3. Purification of the product: The mixed gas of methylsilane and hydrogen chloride generated in S2 above is sent to a cooler for preliminary cooling at a temperature of -40℃ to -60℃ for 5-10 minutes. The boiling point of methylsilane is -22.3℃ under standard atmospheric pressure. The methylsilane is liquefied. The boiling point of hydrogen chloride is -84.9℃ under standard atmospheric pressure. The hydrogen chloride remains in a gaseous state. The methylsilane is discharged from the bottom of the cooler by gravity or pump and collected in a Dewar flask. The separated methylsilane is passed into an adsorption tower and adsorbed by activated carbon before being distilled. The remaining gas is further purified by capturing methylsilane in a cold trap and then distilled to collect hydrogen chloride.

[0047] S4. Regeneration of activated carbon: The regeneration furnace is filled with nitrogen gas, and the internal temperature of the regeneration furnace is set to 150℃-170℃. The nitrogen gas heated in the regeneration furnace is introduced into the adsorption tower, and the hot nitrogen replacement time in the adsorption tower is 50-80 minutes. Afterwards, the adsorption tower is connected to a vacuum pump, and the internal temperature is maintained at -0.095 atm for 110-130 minutes.

[0048] Comparative Example 1

[0049] A green method for the electronic-grade synthesis of methylsilane and hydrogen chloride based on an ionic liquid catalyst includes the following steps:

[0050] S1. Preparation of methylsilane and hydrogen chloride: Keep the high-pressure reactor dry, preheat the reactor for 10-30 min, and set the preheating temperature to 60-80℃. After nitrogen is introduced into the gas inlet of the high-pressure reactor, add the methylchlorosilane mixture and the active metal hydride solid catalyst sequentially through the feed inlet of the high-pressure reactor. Slowly introduce hydrogen through the gas inlet valve of the high-pressure reactor, maintain the pressure at 0.01-20 atm, and set the temperature at 10-350℃ to produce a mixed gas of methylsilane and hydrogen chloride.

[0051] S2. Purification of the product: The mixed gas of methylsilane and hydrogen chloride generated in S1 above is sent to a cooler for preliminary cooling at a temperature of -40℃ to -60℃ for 5-10 minutes. The boiling point of methylsilane is -22.3℃ under standard atmospheric pressure. The methylsilane is liquefied. The boiling point of hydrogen chloride is -84.9℃ under standard atmospheric pressure. The hydrogen chloride remains in a gaseous state. The methylsilane is discharged from the bottom of the cooler by gravity or pump and collected in a Dewar flask. The separated methylsilane is passed into an adsorption tower and adsorbed by activated carbon before being distilled. The remaining gas is further purified by capturing methylsilane in a cold trap and then distilled to collect hydrogen chloride.

[0052] Comparative Example 2

[0053] A green method for the electronic-grade synthesis of methylsilane and hydrogen chloride based on an ionic liquid catalyst includes the following steps:

[0054] S1. Preparation of catalyst: 1-Ethyl-3-methylimidazolium was added to a reaction vessel with an electric stirrer. The speed of the electric stirrer was set to 50-70 rpm. An equimolar amount of aluminum chloride was slowly added to the vessel. The speed of the electric stirrer was then set to 200 rpm and the stirring time was 5 min to ensure uniform mixing of 1-ethyl-3-methylimidazolium and aluminum chloride. The reaction temperature of the electric stirrer was set to 60-80℃ and the reaction time was set to 2 h. After the reaction was complete, the ionic liquid catalyst 1-ethyl-3-methylimidazolium aluminum chloride was obtained.

[0055] S2. Preparation of methylsilane and hydrogen chloride: Keep the high-pressure reactor dry, preheat the reactor for 10-30 min, and set the preheating temperature to 60-80℃. After introducing nitrogen into the gas inlet of the high-pressure reactor, add the methylchlorosilane mixture and the ionic liquid catalyst 1-ethyl-3-methylimidazolium aluminum chloride prepared in S1 sequentially through the feed inlet of the high-pressure reactor. Slowly introduce hydrogen from the gas inlet valve of the high-pressure reactor, maintain the pressure at 0.01-20 atm, and set the temperature at 10-350℃ to produce a mixed gas of methylsilane and hydrogen chloride.

[0056] S3. Purification of the product: The mixed gas of methylsilane and hydrogen chloride generated in S2 above is sent to a cooler for preliminary cooling at a temperature of -40℃ to -60℃ for 5-10 minutes. The boiling point of methylsilane is -22.3℃ under standard atmospheric pressure. The methylsilane is liquefied. The boiling point of hydrogen chloride is -84.9℃ under standard atmospheric pressure. The hydrogen chloride remains in a gaseous state. The methylsilane is discharged from the bottom of the cooler by gravity or pump and collected in a Dewar flask. The separated methylsilane is passed into an adsorption tower and adsorbed by activated carbon before being distilled. The remaining gas is further purified by capturing methylsilane in a cold trap and then distilled to collect hydrogen chloride.

[0057] The following experiments investigated the green synthesis method of electronic-grade methylsilane and hydrogen chloride based on an ionic liquid catalyst, comparing the products in S3 of Examples 1-3 with those in S2 of Comparative Example 1. The yields and production volumes of different catalysts were measured at 5 min and 20 min in a high-pressure reactor. The results are shown in the table below.

[0058]

[0059] Based on the data in the table, and comparing Examples 1, 2, and 3, it can be seen that the products prepared according to the preparation methods in Examples 1, 2, and 3 are better than the products prepared according to the preparation methods in the comparative examples.

[0060] Compared with Comparative Example 1, Example 1 uses 1-ethyl-3-methylimidazolium aluminum chloride instead of an active metal hydride solid as a catalyst. Analyzing the data in the table, within a limited time, the product generation efficiency of Example 1 is higher than that of Comparative Example 1, and the product preparation efficiency is faster. When a certain amount of product is needed, the overall reaction time is relatively short. Within the same time, the product yield of Example 1 is higher than that of Comparative Example 1, which speeds up the overall production rate and allows for the acquisition of more products within a limited time.

[0061] The following experiments were conducted to investigate whether the activated carbon regeneration of Examples 1-3 and Comparative Examples 1-2 was qualified. The results are shown in the table below:

[0062] Methylene blue adsorption value (ml) Iodine adsorption value (mg / g) Example 1 10 990 Example 2 11 980 Example 3 10 970 Comparative Example 1 7 700 Comparative Example 2 6 720 New activated carbon 11 1000

[0063] Based on the data in the table, comparing the methylene blue adsorption value and iodine adsorption value of the regenerated activated carbon and the new activated carbon in Examples 1, 2, and 3, it can be seen that the regenerated activated carbon in Examples 1, 2, and 3 can all meet the adsorption standards.

[0064] In Examples 1, 2, and 3, the adsorption values ​​of activated carbon and new activated carbon for methylene blue and iodine were basically consistent. In Comparative Examples 1 and 2, the activated carbon used was not regenerated, and its adsorption values ​​for methylene blue and iodine were significantly lower than those of the activated carbon in Examples 1, 2, and 3, as well as the new activated carbon. The activated carbon was not regenerated, and its adsorption capacity decreased significantly. The regenerated activated carbon can meet the adsorption standards of activated carbon, can be reused, reduces energy consumption, and is in line with the national green development concept.

[0065] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A green synthesis method for electronic-grade methylsilane and hydrogen chloride based on an ionic liquid catalyst, characterized in that: The preparation method of the electronic-grade methylsilane and hydrogen chloride is as follows: S1. Preparation of catalyst: 1-Ethyl-3-methylimidazolium was added to a reaction vessel with an electric stirrer. The speed of the electric stirrer was set to 50-70 rpm. An equimolar amount of aluminum chloride was slowly added to the vessel. The speed of the electric stirrer was then set to 200-400 rpm, and the stirring time was 5-10 min to ensure uniform mixing of 1-ethyl-3-methylimidazolium and aluminum chloride. The reaction temperature of the electric stirrer was set to 60-80℃, and the reaction time was set to 2 h. After the reaction was complete, the ionic liquid catalyst 1-ethyl-3-methylimidazolium aluminum chloride was obtained. S2. Preparation of methylsilane and hydrogen chloride: Keep the high-pressure reactor dry, preheat the reactor for 10-30 min, and set the preheating temperature to 60-80℃. After introducing nitrogen into the gas inlet of the high-pressure reactor, add the methylchlorosilane mixture and the ionic liquid catalyst 1-ethyl-3-methylimidazolium aluminum chloride prepared in S1 sequentially through the feed inlet of the high-pressure reactor. Slowly introduce hydrogen from the gas inlet valve of the high-pressure reactor, maintain the pressure at 0.01-20 atm, and set the temperature at 10-350℃ to produce a mixed gas of methylsilane and hydrogen chloride. S3. Purification of the product: The mixed gas of methylsilane and hydrogen chloride generated in S2 above is sent to a cooler for preliminary cooling at a temperature of -40℃ to -60℃ for 5-10 minutes. The boiling point of methylsilane is -22.3℃ under standard atmospheric pressure. The methylsilane is liquefied. The boiling point of hydrogen chloride is -84.9℃ under standard atmospheric pressure. The hydrogen chloride remains in a gaseous state. The methylsilane is discharged from the bottom of the cooler by gravity or pump and collected in a Dewar flask. The separated methylsilane is passed into an adsorption tower and adsorbed by activated carbon before being distilled. The remaining gas is further purified by capturing methylsilane in a cold trap and then distilled to collect hydrogen chloride. S4. Regeneration of activated carbon: The regeneration furnace is filled with nitrogen gas, and the internal temperature of the regeneration furnace is set to 150℃-170℃. The nitrogen gas heated in the regeneration furnace is introduced into the adsorption tower, and the hot nitrogen replacement time in the adsorption tower is 50-80 minutes. Afterwards, the adsorption tower is connected to a vacuum pump, and the internal temperature is maintained at -0.095 atm for 110-130 minutes.

2. The green synthesis method of electronic-grade methylsilane and hydrogen chloride based on an ionic liquid catalyst according to claim 1, characterized in that: The molar ratio of 1-ethyl-3-methylimidazolium and aluminum chloride in S1 is 1:

1.

3. The green synthesis method for electronic-grade methylsilane and hydrogen chloride based on an ionic liquid catalyst according to claim 1, characterized in that: The methylchlorosilane mixture in S2 is one, two, or three of methyltrichlorosilane, methyldichlorosilane, and methylmonochlorosilane in a molar ratio of 1:1:1 to 0.01-10:0.01-10:0.01-10.

4. The green synthesis method of electronic-grade methylsilane and hydrogen chloride based on an ionic liquid catalyst according to claim 1, characterized in that: The molar ratio of the methylchlorosilane mixture to hydrogen in S2 is 1-10.

5. The green synthesis method of electronic-grade methylsilane and hydrogen chloride based on an ionic liquid catalyst according to claim 1, characterized in that: In the purification and collection of methylsilane in S3, the separated methylsilane is passed into an adsorption tower at a temperature of -78°C. After the impurities are adsorbed by activated carbon, the methylsilane is passed into a distillation tower at a pressure of 0.1 to 1 atm, a top temperature of -20°C to -30°C, and a bottom temperature of -10°C to 0°C. The methylsilane gas separated in the adsorption tower is preheated to -20°C to -25°C and then sent to the bottom of the distillation tower for distillation. The methylsilane, as a lighter component, is distilled off from the top of the tower, while the impurities, as heavier components, remain at the bottom or are taken out from the middle. The methylsilane vapor at the top of the tower is condensed into liquid by a condenser and collected by a cryogenic storage tank.

6. The green synthesis method of electronic-grade methylsilane and hydrogen chloride based on an ionic liquid catalyst according to claim 5, characterized in that: After methylsilane is liquefied, the remaining gas is captured again to remove any methylsilane that may be present in the remaining gas. A deep cold trap is installed after the cooler, with an operating temperature of -60°C to -80°C, to capture any uncondensed methylsilane.

7. The green synthesis method for electronic-grade methylsilane and hydrogen chloride based on an ionic liquid catalyst according to claim 6, characterized in that: Hydrogen chloride is purified and collected. After methylsilane is captured again, the remaining gaseous hydrogen chloride in the cooler is mainly gaseous hydrogen chloride. The hydrogen chloride is discharged from the cooler, and the cooler is heated. The hydrogen chloride gas is discharged from the cooler and enters the distillation column. The pressure inside the column is set at 0.01-10 atm and the temperature is -50℃-100℃ for two-stage distillation purification to achieve electronic grade purity. The hydrogen chloride vapor at the top of the distillation column is condensed into liquid through a condenser and collected through a Dewar flask.

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