A method and system for purifying methylchlorosilane

Abstract

This invention provides a purification method and system for methylchlorosilane, belonging to the field of methylchlorosilane technology. The purification method employs a three-stage coupled process of complexation reaction pretreatment, two-dimensional layered membrane filtration, and two-stage distillation. This process achieves precise, fractional removal of impurities of different types and forms in methylchlorosilane, ultimately reducing the total impurity content from >1 ppm to <1 ppb. This solves the problem in existing methylchlorosilane purification processes that struggle to remove trace impurities, where the content of these impurities exceeds ppb levels, resulting in low purity and excessive impurity levels. The disclosed purification system includes a complexation reactor and a membrane module with a two-dimensional layered structure membrane, achieving precise removal of trace impurities in methylchlorosilane. This ensures that the obtained methylchlorosilane product meets the raw material requirements of technologies such as semiconductor materials.

Description

Technical Field

[0001] This invention relates to the field of methylchlorosilane technology, and more particularly to a method and system for purifying methylchlorosilane. Background Technology

[0002] Methylchlorosilanes, used as raw materials in the preparation of semiconductor silicon carbide and silicon carbide coatings, require stringent purity standards, with impurity levels needing to be at or below the ppb trace level. Currently, existing purification processes for methylchlorosilanes mainly include multi-stage distillation, repeated distillation, and adsorption. During purification, methylchlorosilanes readily react with trace amounts of water in the system, generating inclusions, colloidal substances, and other impurities that interfere with the purification process. Furthermore, metal chloride impurities in the system have similar physicochemical properties to methylchlorosilanes, making them difficult to remove and resulting in unstable trace impurity levels of methylchlorosilanes at the ppb level.

[0003] When the trace impurity content of methylchlorosilane is higher than the ppb level, the impurity content exceeds the standard, which will cause the impurity content to exceed the limit during the crystal formation process of silicon carbide. This will damage the electrical properties of silicon carbide, significantly reduce its thermal conductivity, and may lead to the overall performance of silicon carbide material being in a state of failure. Summary of the Invention

[0004] The main objective of this invention is to provide a purification method and system for methylchlorosilane, which aims to solve the problems that existing purification processes are unable to remove trace impurities from methylchlorosilane, the content of trace impurities is higher than ppb, the purity of methylchlorosilane is low, and the impurity content exceeds the standard.

[0005] To achieve the above objectives, the present invention provides a method for purifying methylchlorosilane, the purification method comprising: Methylchlorosilane with a total impurity content >1ppm is fed into a reactor, and a chlorine-containing additive is introduced into the reactor to adjust the system to acidity and carry out a complexation reaction. During the complexation reaction, chloride ions are kept in excess to obtain a primary methylchlorosilane purified solution. The primary methylchlorosilane purified solution is passed into a membrane module including a two-dimensional layered membrane, and after membrane filtration, a secondary methylchlorosilane purified solution is obtained. The two-dimensional layered structure membrane includes nanochannels and interlayer channels, and the surface and interlayer of the two-dimensional layered structure membrane are loaded with active functional groups. The purified secondary methylchlorosilane solution was fed into a two-stage distillation column and subjected to a primary light component removal treatment and a secondary heavy component removal treatment to obtain purified methylchlorosilane. The total impurity content of the purified methylchlorosilane is <1 ppb.

[0006] Optionally, the process of feeding methylchlorosilane with a total impurity content greater than 1 ppm into a reactor, introducing a chlorine-containing additive into the reactor to adjust the system to acidity, and carrying out a complexation reaction, wherein chloride ions are kept in excess during the complexation reaction to obtain a primary methylchlorosilane purified solution includes: A chlorine-containing additive is introduced into the reactor, and the molar ratio of the chlorine-containing additive to the metal impurities in the methylchlorosilane is adjusted to 1.2-10:1; The ratio of the flow rate of the chlorine-containing additive to the flow rate of methylsilane is adjusted to 0.05-0.7:1; The reaction time was controlled at 0.5h-4h, the reaction temperature at 10℃-50℃, and the stirring speed at 50r / min-400r / min.

[0007] Optionally, the chlorine-containing additive is capable of dissociating Cl. - The chlorine-containing substance, which can dissociate to release Cl - Chlorine-containing substances include at least one of hydrogen chloride, tin tetrachloride, and antimony trichloride.

[0008] Optionally, in the two-dimensional layered structure membrane, the pore size of the nanochannel is less than the interlayer spacing of the interlayer channels and ≤ 0.6 nm, wherein the pore size of the nanochannel is 0.25 nm to 0.4 nm.

[0009] Optionally, the method for preparing the two-dimensional layered membrane includes: Using an aqueous microporous filter membrane as a substrate, a dispersion of two-dimensional materials was prepared, and then oxygen-containing functional components and nitrogen-containing functional components were added sequentially. The mixture was ultrasonically dispersed and then vacuum filtered to obtain a concentrated solution of two-dimensional sheet materials with a layered structure. Nitrogen-containing and oxygen-containing active functional groups are loaded on the surface and between the layers of the two-dimensional sheet material comprising a stacked structure. The concentrated liquid of the two-dimensional sheet material including the layered structure is vacuum dried and cured to obtain the two-dimensional layered structure film.

[0010] Optionally, the dispersion of the two-dimensional material is an aqueous dispersion of layered oxides, and the concentration of the aqueous dispersion of layered oxides is 1 mg / mL-5 mg / mL; In the step of sequentially adding the oxygen-containing functional component and the nitrogen-containing functional component, the amount of the oxygen-containing functional component added is 0.05 g / mL–0.2 g / mL, and the amount of the nitrogen-containing functional component added is 0.05 g / mL–0.2 g / mL.

[0011] Optionally, the layered oxide is graphene oxide, layered titanate, or niobate.

[0012] Optionally, the oxygen-containing functional component includes at least one of citric acid, glycolic acid, polyethylene glycol, and carboxymethyl cellulose; the nitrogen-containing functional component includes at least one of urea, ethylenediamine, polyethyleneimine, and melamine.

[0013] Optionally, the method of feeding the purified secondary methylchlorosilane solution into a two-stage distillation column, and sequentially undergoing a primary light component removal treatment and a secondary heavy component removal treatment to obtain purified methylchlorosilane includes: The tower pressure for the first-stage light component removal process is 25 kPa-55 kPa, the tower top temperature is 10℃-40℃, the tower bottom temperature is 25℃-58℃, and the reflux ratio is 10-15:1. The pressure of the secondary deweighting treatment tower is 10kPa-40kPa, the top temperature is 15℃-40℃, the bottom temperature is 30℃-55℃, and the reflux ratio is 6-25:1.

[0014] To achieve the above objectives, the present invention also provides a purification system for methylchlorosilane, for implementing the purification method described above. The purification system includes a complexation reaction processing unit, a membrane separation unit, and a two-stage distillation unit. The complexation reaction processing unit includes a chlorine-containing auxiliary agent storage device. The membrane separation unit is assembled from membrane modules connected in series and / or in parallel. The membrane modules include a two-dimensional layered membrane structure.

[0015] Compared with the prior art, the beneficial effects that the present invention can achieve are as follows.

[0016] 1. The purification method for methylchlorosilane disclosed in this invention employs a three-stage coupled process: complexation reaction pretreatment, two-dimensional layered membrane filtration, and two-stage distillation. This process achieves precise removal of different types and forms of impurities from methylchlorosilane, ultimately reducing the total impurity content from >1 ppm to <1 ppb. During the complexation reaction, the chlorine-containing auxiliary agent, under acidic conditions, can form stable high-boiling-point chlorine complexes with ions of metals such as Fe, Al, Cu, and Ni, such as FeCl3 and AlCl3. Some excess Cl... - It can form complexes with metal ions to form complex anions, such as [FeCl4]. - [AlCl4] -Furthermore, it can undergo complexation or addition reactions with some polar organic impurities, such as siloxanes containing hydroxyl and amino groups, thereby converting difficult-to-separate dissolved impurities into macromolecules or high-boiling-point substances. In the second step of membrane filtration, on the one hand, the physical sieving effect of nanochannels intercepts macromolecular complexes, colloidal particles, and suspended solids generated by the complexation reaction; on the other hand, the active functional groups loaded on the surface and interlayer of the two-dimensional layered membrane form coordination bonds with residual trace metal ions and hydrogen bonds with polar impurities, thereby further achieving the adsorption and removal of impurities. After membrane filtration, the two-stage distillation process removes low-boiling-point organic impurities such as chloromethane, trichlorosilane, and silicon tetrachloride. The second-stage heavy-weight removal column removes high-boiling-point organic impurities, achieving trace control of organic impurities. This results in the final methylchlorosilane product having a total impurity content of <1 ppb, solving the problem that existing methylchlorosilane purification processes struggle to remove trace impurities, have impurity levels exceeding 1 ppb, and exhibit low purity and excessive impurity content.

[0017] 2. The methylchlorosilane product obtained by the purification method disclosed in this invention can be used in the preparation of organosilicon materials such as photoresist siloxanes, electronic-grade encapsulation silicone, and wafer dicing protective adhesives, ensuring that the prepared products have excellent electrical properties.

[0018] 3. The methylchlorosilane purification system disclosed in this invention includes a complexation reactor and a membrane module with a two-dimensional layered structure membrane, which can achieve precise removal of trace impurities in methylchlorosilane, so that the purified methylchlorosilane product can meet the requirements for the preparation of semiconductor materials. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the purification method for methylchlorosilane disclosed in this invention. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] To address the problem that existing purification processes for methylchlorosilane struggle to remove trace impurities, resulting in impurity levels exceeding ppb and low purity, this invention provides a purification method for methylchlorosilane, comprising: Methylchlorosilane with an impurity content >1ppm is fed into a reactor, and a chlorine-containing additive is introduced into the reactor to adjust the system to acidity and carry out a complexation reaction. During the complexation reaction, chloride ions are kept in excess to obtain a primary methylchlorosilane purified solution. The primary methylchlorosilane purified solution is passed into a membrane module including a two-dimensional layered membrane, and after membrane filtration, a secondary methylchlorosilane purified solution is obtained. The two-dimensional layered structure membrane includes nanochannels and interlayer channels, and the surface and interlayer of the two-dimensional layered structure membrane are loaded with active functional groups. The purified secondary methylchlorosilane solution was fed into a two-stage distillation column and subjected to a primary light component removal treatment and a secondary heavy component removal treatment to obtain purified methylchlorosilane. The total impurity content of the purified methylchlorosilane is <1 ppb.

[0022] It should be understood that in the methylchlorosilanes with a total impurity content > 1 ppm, the total impurity content refers to the total content of inorganic elemental impurities contained in the methylchlorosilane, such as metal ion impurities. Furthermore, under the technical solutions disclosed in this invention, it is also possible to reduce the total content of impurities such as inorganic elemental impurities, hydrochlorosilanes, hydrocarbons, moisture, high-boiling-point substances, and low-boiling-point substances to below 1 ppb. Based on this result, in the above description of a total impurity content > 1 ppm, the total impurity content can also refer to the total content of impurities such as inorganic elemental impurities, hydrochlorosilanes, hydrocarbons, moisture, high-boiling-point substances, and low-boiling-point substances.

[0023] It should be understood that the above-mentioned acidity of the system is adjusted by chlorine-containing additives because the methylchlorosilane system is an anhydrous organic system and does not have the concept of pH value in aqueous solution. Therefore, acidity refers to the concentration or partial pressure of hydrogen chloride in the system.

[0024] Optionally, during the complexation reaction described above, the concentration of hydrogen chloride can be controlled to be between 1 ppm and 100 ppm.

[0025] Optionally, in the technical solution of the present invention, the total impurity content of methylchlorosilane can be 1ppm-100ppm.

[0026] Optionally, in the technical solution of the present invention, methylchlorosilane can be methyltrichlorosilane, methyldichlorosilane, methylmonochlorosilane, dimethylchlorosilane, dimethyldichlorosilane or trimethylchlorosilane.

[0027] Optionally, the membrane assembly including the two-dimensional layered structure membrane can be spiral wound, tubular, or flat.

[0028] Optionally, the two-stage distillation column can be a packed column or a plate column.

[0029] It should be noted that in the technical solution disclosed in this invention, methylchlorosilane is purified to achieve a total impurity content of <1 ppb in the purified methylchlorosilane product. This total impurity content generally refers to the total content of inorganic element impurities, such as the total content of inorganic element impurities like Al, Fe, Ca, Na, K, Cu, Zn, Cr, Ni, and B. When the total content of these inorganic element impurities is <1 ppb, it indicates that the metal purity of the methylchlorosilane product has reached electronic grade and high-purity standards. In high-end applications such as semiconductors and photovoltaics, metal impurities are a key limiting indicator, and this result demonstrates that the product can meet the stringent requirements for metal impurities in such applications.

[0030] In some implementations, the process of feeding methylchlorosilane with a total impurity content >1 ppm into a reactor, introducing a chlorine-containing additive into the reactor to adjust the system to acidity, and carrying out a complexation reaction, while maintaining an excess of chloride ions during the complexation reaction to obtain a primary methylchlorosilane purified solution includes: A chlorine-containing additive is introduced into the reactor, and the molar ratio of the chlorine-containing additive to the metal impurities in methylchlorosilane is adjusted to 1.2:1-10:1. The ratio of the flow rate of the chlorine-containing additive to the flow rate of methylsilane is adjusted to 0.05-0.7:1; The reaction time was controlled at 0.5h-4h, the reaction temperature at 10℃-50℃, and the stirring speed at 50r / min-400r / min.

[0031] It should be noted that in the above-mentioned schemes involving the addition of chlorine-containing additives, the theoretical dosage of the chlorine-containing additive can be determined based on the type of metal impurity required for complete complexation. - The quantity is calculated. Furthermore, during the complexation reaction, a detection device can be installed on the reactor to monitor the free Cl in the reaction solution in real time. - Concentration, when Cl - Automatic replenishment when the concentration falls below the set threshold.

[0032] Optionally, when adding chlorine-containing additives, a staged addition method can be adopted. For example, about 80% of the theoretical dosage can be added first, and then the remaining 20% ​​can be added according to the monitoring results. This ensures that chloride ions are in excess while avoiding extreme excess of chloride ions.

[0033] Optionally, during the complexation reaction described above, a segmented temperature control method can be adopted. For example, in the first stage, such as the first 0.3 hours of the reaction, the reaction temperature can be controlled at 30℃-40℃ to accelerate the complexation kinetics; in the second half of the reaction, the temperature can be adjusted to 20℃-25℃ to stabilize the complex and prevent dissociation.

[0034] Optionally, a segmented stirring method can be used in the above complexation reaction process. For example, during the feeding stage, the stirring speed can be controlled at 200 r / min-400 r / min; during the reaction stage, the stirring speed can be controlled at 100 r / min-200 r / min; and during the final stage of the reaction, the stirring speed can be controlled at 50 r / min-100 r / min.

[0035] Optionally, in the complexation reaction process disclosed in this invention, the flow rates of methylsilane and chlorine-containing additives can be adjusted according to the actual operating equipment and production capacity requirements. For example, at a reaction temperature of 10℃-50℃, preferably 20℃-40℃, the flow rate of methylsilane can be adjusted to 300L / H-500L / h, and the flow rate of chlorine-containing additives can be adjusted to 15L / H-40L / h, while ensuring that the flow rate ratio of the two is 0.05-0.7:1.

[0036] It should be noted that in the above complexation reaction process, the molar ratio of the chlorine-containing auxiliaries to the metal impurities in methylchlorosilane is controlled to be 1.2:1-10:1. Under these conditions, relative to the metal impurities, Cl... - It can maintain an excess of 20%-900% to drive the complexation equilibrium toward the product; for Fe 3+ Al 3+ Na + Common metal ions can form stable [MCl] n ] (n-m)- The reaction mixture consists of anionic or neutral complexes (M represents a metal ion). The reaction time is controlled between 0.5h and 4h. A 0.5h reaction time satisfies the rapid complexation kinetics of most ionic metals, while a 4h reaction time covers the slow dissolution-complexation process of oxide colloidal impurities, ensuring near-equilibrium. Within the reaction time, the reaction temperature is maintained between 10℃ and 50℃. Temperatures above 10℃ ensure system fluidity and prevent increased viscosity of methylchlorosilane at low temperatures; temperatures below 50℃ prevent thermal dissociation of the complex. This balance between reaction rate and complex stability is achieved according to the Arrhenius relation (a quantitative law that chemical reactions proceed faster at higher temperatures). During the reaction, stirring is performed at 50r / min to 400r / min. Stirring above 50r / min creates effective turbulence, ensuring uniform gas-liquid and liquid-liquid dispersion; stirring below 400r / min avoids shear damage to the complex or the introduction of abrasive impurities into the equipment.

[0037] After the above complexation reaction, the size of impurities in the complexation reaction system increases after forming complex products; for example, free Fe... 3+ The hydrated ion is approximately 0.6 nm in size and forms a complex with [FeCl4]. -The post-kinetic size may increase to 0.8 nm-1.0 nm, larger than the interlayer spacing of the interlayer channels, thus allowing for effective sieving by the layered membrane; the charge state may change, for example, by forming complex anions, such as [AlCl4]. - With the membrane surface and interlayer -NH3 + The active functional groups can generate Donnan repulsion or electrostatic adsorption (a charge effect of like charges repelling each other) to fix the membrane, further enhancing the retention rate; at the same time, the dissolved state tends to be stable, which avoids the random aggregation of metal oxide colloids and can prevent the problem of irreversible blockage of membrane pores.

[0038] Furthermore, in the above complexation reaction process, when the ratio of the flow rate of the chlorine-containing auxiliary agent to the flow rate of methylsilane is controlled at 0.05-0.7:1, the volumetric flow rate ratio of the auxiliary agent to methylchlorosilane is within a controllable range, thereby decoupling and controlling the residence time (τ) and molar ratio (α) in the reactor. This can avoid local over-concentration caused by high molar ratio and low flow rate conditions, or membrane perforation caused by low molar ratio and high flow rate conditions.

[0039] In some embodiments, the chlorine-containing additive described above is capable of dissociating Cl. - Chlorine-containing substances can dissociate to release Cl. - Chlorine-containing substances include at least one of hydrogen chloride, tin tetrachloride, and antimony trichloride.

[0040] It should be noted that in the technical solution of this invention, hydrogen chloride (HCl) can be used as a general chlorine-containing additive when selecting chlorine-containing additives. However, tin tetrachloride (SnCl4) and antimony trichloride (SbCl3) contain inherent metal ion impurities, so these two chlorine-containing additives are generally not used alone in specific implementations, as adding large amounts of these two additives may introduce new metal ion impurities. Under specific conditions, these two chlorine-containing additives can be used in combination with HCl, for example, when the methylchlorosilane system contains oxygen-containing ligand impurities, such as metal oxides, alkoxides, or noble metal ion impurities, such as Au. 3+ Pt 4 + Pd 2+ Or rare earth metal ions, such as La 3+ Ce 4+ In such cases, SnCl4 or SbCl3 can be selected as one of the chlorine-containing additives.

[0041] In the technical solution of this invention, if the metal impurity of the methylchlorosilane system is a conventional metal ion impurity, such as Fe... 3+ Al 3+ Na 2+For processes like these, HCl can be used as a chlorine-containing additive to meet the requirements. Furthermore, when the total impurity content of the methylchlorosilane system is >100 ppm, the use of SnCl4 or SbCl3 as chlorine-containing additives can be disregarded.

[0042] Optionally, when the above-mentioned chlorine-containing additive is a mixture of hydrogen chloride (HCl) and tin tetrachloride (SnCl4), the molar ratio of HCl to SnCl4 can be 9:1.

[0043] When the aforementioned chlorine-containing additive is a mixture of HCl and SnCl4, HCl can provide free Cl- during the complexation reaction. - Rapidly complexing Fe 3+ Al 3+ SnCl4 can complex difficult-to-remove metal ion impurities. This method not only significantly reduces the amount of chlorine-containing additives needed but also significantly increases the complexation rate of metal ions, thereby significantly improving the impurity removal rate.

[0044] Optionally, when the chlorine-containing auxiliary agent is a mixture of HCl and antimony trichloride (SbCl3), the molar ratio of HCl to SbCl3 can be 8:2. HCl can increase the complexation reaction rate, while SbCl3 provides highly selective complexation, further reducing residual metal ion impurities.

[0045] It should be noted that in the complexation reaction described above, when the chlorine-containing auxiliary agent is HCl, it can completely dissociate into H+ in anhydrous methylchlorosilane. + and free Cl - Furthermore, the reaction rate is relatively high; according to existing literature, the complexation reaction with metal ions can generally reach equilibrium within milliseconds. In addition, during the subsequent two-stage distillation and refining process, when the temperature reaches 80°C or higher, residual HCl may be completely removed and will not remain in the product.

[0046] When the aforementioned chlorine-containing additives include SnCl4, they can not only provide Cl - It forms common chloride complexes and can also act as a strong Lewis acid with boron ions and Ni. 2+ Cu 2+ Co 2+ Transition metal ions can form stable bimetallic complexes, such as [Ni(SnCl6)]. 2- [Cu(SnCl4)], and has high stability. Furthermore, when Ni in the system... 2+ Cu 2+ Even at concentrations below ppm, SnCl4 can undergo strong complexation reactions with SnCl4, significantly increasing the complexation rate.

[0047] When the aforementioned chlorine-containing additives include SbCl3, it can form a dense passivation film on the surface of the reaction equipment, such as an SbCl3-FeCl3 composite passivation film. This film can inhibit the corrosion of equipment containing iron (Fe), cobalt (Co), and nickel (Ni) by the strong acidity of the system. For example, adding SbCl3 to a system containing HCl can significantly reduce the corrosion rate of the equipment. Furthermore, SbCl3 reacts with Fe... 3+ Al 3+ The stability constant of the formed complex is higher than that of complexes of other metal ions, and can be found in Ni. 2+ Cu 2+ In the presence of impurities, Fe is preferentially removed. 3+ Al 3+ Removal efficiency can reach 0.1 ppb or less. Furthermore, if SbCl3 is added in excess, it can be removed in the subsequent secondary deweighting process and will not remain in the product.

[0048] In some implementations, the pore size of the nanochannels in the above-mentioned two-dimensional layered structure membrane is less than the interlayer spacing of the interlayer channels and ≤ 0.6 nm, wherein the pore size of the nanochannels is 0.25 nm-0.4 nm; Optionally, the total thickness of the above-mentioned two-dimensional layered membrane can be 50nm-500nm, which can not only ensure the high flux of the membrane filtration process, but also ensure sufficient mechanical strength.

[0049] After the above complexation reaction, the resulting primary methylchlorosilane purified solution contains methylchlorosilane molecules as the main product, possibly accounting for over 99%. Impurities to be removed may include metal chloride complex anions, such as [FeCl4]. - [AlCl4] - [NaCl2] - etc.; metal chloride complex MCl n Such as FeCl3 and AlCl3; if the methylchlorosilane system contains alkoxide impurities, it may also contain metal-organic complex (M-OR) impurities; and incompletely complexed residual metal ions. In addition, it may also include excess free Cl-. - Residual H + wait.

[0050] According to existing research, the kinetic diameter of methylchlorosilane molecules is approximately 0.4 nm. The molecular size of the metal chloride complex anion obtained after the complexation reaction may be 0.4 nm-0.6 nm, and the molecular size of the metal chloride complex may be 0.3 nm-0.5 nm. Therefore, when using the aforementioned two-dimensional layered membrane for fine filtration, smaller metal chloride complexes will be retained by the nanochannels. Metal chloride complex anions, siloxane dimers, and polycyclic compounds with a kinetic diameter > 0.4 nm cannot pass through the nanochannels and will be enriched and concentrated on the membrane surface along with the mainstream liquid. When the liquid enters the interlayer channel, the active functional groups on the channel wall surface and interlayer will exhibit chemical recognition. For the following metal complex anions, the positively charged -NH3 group in the interlayer... + This will produce a strong Donnan repulsion effect, separating these negatively charged impurities; for metal ions that may exist in the form of free cations, the negatively charged -COO - -NH2 molecules, which may possess lone pairs of electrons, can be fixed to the interlayer channel walls through coordination or electrostatic adsorption, achieving a removal effect. Meanwhile, methylchlorosilane molecules, as weakly polar organosilicon compounds, lack strong interactions with the hydrophilic functional groups in the interlayer. Due to their hydrophobic properties, they maintain high slip diffusion capacity within the channels, continuously permeating towards the low-pressure side along the interlayer channels, eventually converging on the permeate side to form a high-purity methylchlorosilane enrichment solution. Water molecules and hydrogen chloride molecules, with sizes potentially <0.25 nm, may cross the membrane structure and be removed in subsequent two-stage distillation columns.

[0051] For the two-dimensional layered membrane structure disclosed in this invention, if the interlayer spacing of the interlayer channels is less than the pore size of the nanochannels and less than 0.6 nm, some metal chloride complexes formed after complexation may pass smoothly through the nanochannels, causing the active functional groups loaded on the interlayer channels to be unable to function and thus unable to be effectively retained, eventually resulting in a large amount of leakage to the permeate side; while for the target methylchlorosilane molecules with a kinetic size of about 0.4 nm, they may not be able to pass through the interlayer channels and be retained in large quantities; ultimately, the structured membrane will not only fail to produce high-purity methylchlorosilane, but will also experience irreversible blockage due to the severe accumulation of the target product on the membrane surface and at the inlet.

[0052] In some implementations, the preparation method of the above-mentioned two-dimensional layered membrane includes: Using an aqueous microporous filter membrane as a substrate, a dispersion of two-dimensional materials was prepared, and then oxygen-containing functional components and nitrogen-containing functional components were added sequentially. The mixture was ultrasonically dispersed and then vacuum filtered to obtain a stacked two-dimensional sheet structure material. Nitrogen-containing and oxygen-containing active functional groups are loaded on the surface and between the layers of the stacked two-dimensional sheet structure material. Two-dimensional layered structure materials are vacuum dried and cured to obtain a two-dimensional layered structure film.

[0053] In some instances, the aforementioned layered oxides can be graphene oxide, layered titanates, or niobates.

[0054] Optionally, the pore size of the above-mentioned water-based microporous filter membrane can be 0.22μm-0.45μm.

[0055] Optionally, in the preparation of the above-mentioned two-dimensional layered structure membrane, the reaction parameters can be: reaction temperature 40℃-60℃, reaction time 4h-8h.

[0056] Optionally, in the process of preparing the two-dimensional layered membrane, the ultrasonic dispersion parameters can be: ultrasonic power 200W-300W, ultrasonic time 1h-2h, and ultrasonic temperature 10℃-30℃.

[0057] Optionally, in the process of preparing the two-dimensional layered membrane, the parameters for vacuum filtration can be: vacuum degree of -0.05MPa to -0.09MPa, filtration volume or area control membrane thickness of 50nm to 200nm, and washing after filtration.

[0058] Optionally, when vacuum drying and curing the stacked two-dimensional sheet structure material as described above, the drying and curing process parameters can be vacuum drying at 60°C for 6h–12h.

[0059] It should be noted that in the above-mentioned preparation of two-dimensional layered membranes, the two-dimensional material is graphene oxide, etc. During its dispersion in an aqueous system, hydroxylation reactions occur at the surface edges and defects to generate hydroxyl groups (-OH). During and after oxidation, epoxy groups (COC) can be formed on the surface of the two-dimensional material sheets, and a small amount of carbonyl groups (C=O) can be generated at the edges. When oxygen-containing functional components are introduced, carboxyl groups (-COOH), alcohol hydroxyl groups (-OH), phenolic hydroxyl groups (-OH), etc., can be formed in the system. When nitrogen-containing functional components are introduced, primary amino groups (-NH2), secondary amino groups (-NH-), tertiary amino groups (-N<), and pyridine nitrogen (Ar-N) can be formed in the system. During the vacuum drying and curing process of the stacked two-dimensional layered material, covalent bonding reactions occur between the oxygen-containing functional components and the nitrogen-containing functional components, and between the functional components and the two-dimensional material, generating stable derived functional groups, such as amide groups (-CONH-) and imine groups (-C=N-). These derived functional groups can prevent the functional components from dissolving.

[0060] Furthermore, the two-dimensional layered membrane prepared by the above method is used in the process of finely filtering the primary methylchlorosilane purification solution after the complexation reaction. After the complexation reaction, trace amounts of free metal ions, such as boron ions, including B, remain in the methylchlorosilane solution. 3+ B + B 2+ Fe 3+ Al 3+ Cu 2+ Ni 2+ The film contains: low-coordinate metal chloride complexes, such as [FeCl3] and [CuCl2]; polar organic impurities, such as hydroxysiloxanes, aminosiloxanes, and carbonyl siloxane oligomers; and nanoscale colloidal particles, such as silica microcrystals and metal complex aggregates. Free metal ions, including the metal centers of low-coordinate complexes, possess empty d orbitals (Lewis acids), while nitrogen- and oxygen-containing functional groups contain lone pairs of electrons (Lewis bases). These ions can form stable metal-ligand complexes through coordinate bonds, thereby immobilizing the metal impurities within the film. For polar organic impurities, whose molecular size is close to that of methylchlorosilanes, they can be removed through hydrogen bond adsorption. For example, -OH and -COOH in oxygen-containing functional groups can act as hydrogen bond donors, and C=O and COC can act as hydrogen bond acceptors, removing polar organic impurities such as aminosiloxanes and carbonylsiloxanes. -NH2 and -NH- in nitrogen-containing functional groups can act as hydrogen bond donors, and -N< and pyridine nitrogen can act as hydrogen bond acceptors, removing hydroxysiloxanes and carbonylsiloxanes. The specific bonding mechanism may be that -OH of hydroxysiloxanes may form OH…O hydrogen bonds with -COOH on the two-dimensional layered membrane, and at the same time, it can form OH…N hydrogen bonds with -NH2 on the membrane, thereby being adsorbed and retained, achieving the purpose of removal. For the contained nanoscale colloidal particles, there are two ways to remove them. One is physical sieving. When the interlayer spacing and in-plane pore size of the interlayer channels of the two-dimensional layered membrane are less than the size of the colloidal particles, almost all colloidal particles can be physically retained by the membrane surface and the upper layer of the sheet structure. The second is electrostatic adsorption. The -COOH and -NH2 functional groups on the surface of the two-dimensional layered membrane can be weakly dissociated in an anhydrous system and have a small amount of charge. They can adsorb colloidal particles with opposite charges through electrostatic interaction, preventing them from entering the next stage and reducing the clogging of membrane pores by colloidal particles.

[0061] Based on the above analysis, in the technical solution of this invention, the method for fine filtration of the solution after complexation reaction using a membrane module comprising a two-dimensional layered membrane is as follows: First, the solution contacts the surface of the two-dimensional layered membrane. During this process, larger metal complexes and colloidal particles can be physically retained by the surface nanopores and the edges of the sheets. Simultaneously, some charged colloids and polar impurities are adsorbed by the functional groups on the membrane surface through electrostatic and hydrogen bonding interactions. Second, the solution permeates through the surface and enters the interlayer channels. During this process, trace impurity isomers are physically retained by the interlayer channels. Residual free metal ions, low-coordination complexes, and polar organic impurities, during their passage through the long interlayer path, come into full contact with the densely distributed functional groups and are quantitatively adsorbed through coordination and hydrogen bonding interactions. Third, impurity molecules that may permeate through the interlayer channels can be retained by the in-plane nanopores. Simultaneously, the functional groups around the pores can undergo further adsorption and capture. Finally, a finely filtered secondary methylchlorosilane purified solution is obtained.

[0062] In some instances, the dispersion of the two-dimensional material is an aqueous dispersion of layered oxides, with a concentration of 1 mg / mL to 5 mg / mL.

[0063] In the above steps of sequentially adding oxygen-containing functional components and nitrogen-containing functional components, the amount of oxygen-containing functional components added is 0.05 g / mL–0.2 g / mL, and the amount of nitrogen-containing functional components added is 0.05 g / mL–0.2 g / mL.

[0064] In some instances, the oxygen-containing functional components include at least one of citric acid, glycolic acid, polyethylene glycol, and carboxymethyl cellulose; the nitrogen-containing functional components include at least one of urea, ethylenediamine, polyethyleneimine, and melamine.

[0065] It should be noted that when the above-mentioned oxygen-containing functional components are citric acid, glycolic acid, or carboxymethyl cellulose, the main functional groups that can be introduced include -COOH and -OH; when it is polyethylene glycol, the main functional groups that can be introduced include ether bonds (COC) and terminal hydroxyl groups (-OH). When the above-mentioned nitrogen-containing functional components are urea, the main functional groups that can be introduced include primary amino groups (-NH2) and amide groups (-CONH-); when it is ethylenediamine, the main functional groups that can be introduced include -NH2; when it is polyethyleneimine, the main functional groups that can be introduced include -NH2, secondary amino groups (-NH-), and tertiary amino groups (-N<); when it is melamine, the main functional groups that can be introduced include -NH2 and triazine ring nitrogen (Ar-N). These nitrogen-containing functional groups all contain basic nitrogen atoms and have lone pairs of electrons, which are the main active sites for the coordination adsorption of metal ions.

[0066] In some instances, the method described above, in which the purified secondary methylchlorosilane solution is fed into a two-stage distillation column and subjected to a primary light component removal process and a secondary heavy component removal process to obtain purified methylchlorosilane, includes: The pressure of the column for the first-stage removal of light components is 25 kPa-55 kPa, the top temperature is 10℃-40℃, the bottom temperature is 25℃-58℃, and the reflux ratio is 10-15:1; the pressure of the column for the second-stage removal of heavy components is 10 kPa-40 kPa, the top temperature is 15℃-40℃, the bottom temperature is 30℃-55℃, and the reflux ratio is 6-25:1.

[0067] After the above two-stage distillation process, for systems with a boiling point difference > 8℃, the high-boiling-point recovery rate may reach over 9.99%; for difficult-to-separate pairs with a boiling point difference between 4℃ and 5℃, the recovery rate may be in the range of 99.95% to 99.99%.

[0068] Optionally, during the distillation process, the reboiler temperature is ≤ the boiling point of the target product at the operating pressure + 8°C; at the same time, the reboiler temperature is ≤ 60°C to prevent overheating and decomposition of the target product.

[0069] Optionally, the number of trays in the distillation column can be 30 to 71.

[0070] It should be noted that in the technical solution disclosed in this invention, during the above-mentioned primary light component removal and secondary heavy component removal processes, appropriate process parameters can be selected according to the specific product to be purified. For example, when methylchlorosilane is methyltrichlorosilane (MTCS), the process parameters for the primary light component removal process can be a column pressure of 25 kPa-35 kPa, a column top temperature of 32℃-38℃, a column bottom temperature of 48℃-58℃, and a reflux ratio of 12-18:1. The process parameters for the secondary heavy component removal process can be a column pressure of 10 kPa-20 kPa, a column top temperature of 28℃-35℃, a column bottom temperature of 45℃-55℃, and a reflux ratio of 6-8:1. For example, when methylchlorosilane is trimethylchlorosilane (TMCS), the process parameters for the primary light component removal process can be a column pressure of 25 kPa-40 kPa, a column top temperature of 20℃-28℃, a column bottom temperature of 35℃-45℃, and a reflux ratio of 10:1. It is important to note that when purifying methylchlorosilane (MMCS), separate high-pressure distillation is required, such as fine filtration at 200 kPa-500 kPa, or cryogenic distillation, such as fine filtration at the top of the column at <-20°C. When purifying methyldichlorosilane (MDCS) or dimethylchlorosilane (DMCS), the first-stage light removal pressure can be increased to 40 kPa-55 kPa, and the top temperature can be 10°C-20°C.

[0071] It should be noted that in the two-stage distillation process disclosed in this invention, when selecting parameters, it is necessary to avoid the combination of high temperature and low pressure, and low temperature and high pressure. The main direction should be the parameter selection trend of low temperature and low pressure, and high temperature and high pressure. For example, when the operating pressure is 25 kPa-35 kPa, the top temperature of the column can be 20℃-35℃, and the bottom temperature can be 30℃-45℃; when the operating pressure is 35 kPa-55 kPa, the top temperature of the column can be 30-50℃, and the bottom temperature can be 40-58℃.

[0072] The purified secondary methylchlorosilane solution obtained by membrane filtration may contain trace impurities such as residual chlorine-containing additives, low-boiling-point organic impurities, high-boiling-point organic impurities, and other trace impurities. During the first-stage light component removal, all impurities with boiling points lower than the target methylchlorosilane are completely separated from the top of the column. The crude product obtained from the light component removal, such as residual HCl, chloromethane, and trichlorosilane, is rapidly vaporized and concentrated at the top of the column. The light component mixture collected at the top can be recycled to the synthesis section for reuse. After the first-stage light component removal, the second-stage heavy component removal separates all impurities with boiling points higher than the target methylchlorosilane from the bottom of the column. The final high-purity product is obtained at the top of the column. For example, impurities with higher boiling points such as carbon tetrachloride, tin tetrachloride, antimony trichloride, and siloxane oligomers are concentrated at the bottom of the column, while impurities with boiling points close to methylchlorosilane can be further separated through the trays and collected at the bottom of the column. The heavy component mixture collected at the bottom can be further recovered for useful components; high-purity methylchlorosilane is collected at the top of the column.

[0073] As the above analysis shows, the purification method disclosed in this invention can not only reduce the total content of inorganic elemental impurities in methylchlorosilanes to below 1 ppb, but also potentially reduce the organic impurities, such as other methylchlorosilane isomers, ethylchlorosilanes, high-boiling substances, and siloxane oligomers, to below 1 ppb. This results in the final methylchlorosilane product having a total impurity content that is maintained below 1 ppb, thus yielding a 9N-grade methylchlorosilane product. Therefore, in the technical solution disclosed in this invention, the total impurity content can also refer to the total content of inorganic elemental impurities, organic impurities, and other impurities.

[0074] To achieve the above objectives, the present invention also provides a purification system for methylchlorosilane, for implementing the purification method described above. The purification system includes a reaction complexation unit, a membrane separation unit, and a two-stage distillation purification unit. The reaction complexation unit includes a chlorine-containing auxiliary agent storage device. The membrane separation unit is assembled from membrane modules connected in series and / or in parallel. The membrane modules include a two-dimensional layered membrane structure.

[0075] Using this purification system, methylchlorosilane with a total impurity content greater than 1 ppm can be purified into a high-purity methylchlorosilane product with a total impurity content less than 1 ppb.

[0076] Example 1 A purification system for methyltrichlorosilane is provided for purifying methyltrichlorosilane products. The purification system includes a reaction complexation unit, a membrane separation unit, and a two-stage distillation purification unit. The reaction complexation unit includes a chlorine-containing auxiliary agent storage device. The membrane separation unit is assembled by assembling membrane modules in series and parallel. The membrane modules include two-dimensional layered membrane structures. The purification system for methyltrichlorosilane was used to purify methyltrichlorosilane with a total impurity content >50 ppm. Specific purification methods included: S10. Methyltrichlorosilane was introduced into a complexation reactor. The total content of metallic and non-metallic impurities in the methyltrichlorosilane was >50 ppm. Stirring was started and the rotation speed was adjusted to 250 r / min. The jacket cooling water was turned on to stabilize the material temperature at 25℃. A mixed auxiliary agent of HCl and SnCl4 was continuously introduced at a molar ratio of 2.5:1 for the chlorine-containing auxiliary agent to the metallic impurities, with a molar ratio of 9:1 for HCl to SnCl4. The flow rate ratio of the chlorine-containing auxiliary agent to the methylsilane was adjusted to 0.05:1, and the reaction was continued for 3.0 h. After the reaction was completed, a primary methyltrichlorosilane purified solution was obtained. S20. The primary methyltrichlorosilane purified solution obtained in S10 is passed into a membrane module including a two-dimensional layered membrane. The operating pressure is adjusted to 1.8 MPa, the operating temperature to 28 °C, the flow rate to 0.5 m / s, and the membrane feed rate to 1 kg / h. After membrane filtration, a secondary methyltrichlorosilane purified solution is obtained. The preparation method of the two-dimensional layered structure membrane is as follows: Using an aqueous microporous membrane with a pore size of 0.22 μm as the substrate and graphene oxide as the layered oxide two-dimensional material, an aqueous dispersion of the two-dimensional material with a concentration of 3 mg / mL was prepared. Then, urea and citric acid were added at a ratio of 0.2 g / mL, and the mixture was sonicated for 50 min to obtain a mixture. The mixture was poured into a vacuum filtration device, and a concentrated solution of two-dimensional sheet material with a layered structure was obtained after filtration. The solution was vacuum dried at 60°C for 10 h, and after natural exfoliation, a two-dimensional layered structure membrane was obtained. S30. The purified secondary methyltrichlorosilane solution obtained in S20 is fed into a two-stage distillation column, where it undergoes a primary light component removal process followed by a secondary heavy component removal process to obtain purified methyltrichlorosilane, specifically as follows: The purified secondary methyltrichlorosilane solution obtained from S20 was fed into a primary light component removal column. The system was first evacuated, and the column pressure was adjusted to 25 kPa. The top temperature of the column was stabilized at 38°C, and the bottom temperature was controlled at 45°C. The total condenser was cooled with 5°C chilled water, and the reflux ratio was set to 10:1. The light component was initially collected from the top of the column, and the light component removal-reduced methyltrichlorosilane enriched solution was obtained from the bottom of the column. The methyltrichlorosilane enriched solution after light removal is sent to a secondary heavy removal tower. The system is first evacuated, and the tower pressure is adjusted to 18 kPa, the top temperature is 33℃, the bottom temperature is <45℃, and the reflux ratio is set to 20:1. High-purity product is collected from the top of the tower, and the residual liquid in the bottom of the tower is continuously discharged for further recycling.

[0077] After passing through S10-S30, methyltrichlorosilane with a total impurity content >50ppm is purified into a high-purity methyltrichlorosilane product with a total impurity content <1ppb.

[0078] The types and contents of inorganic elemental impurities in the high-purity methyltrichlorosilane product obtained in Example 1 were determined by inductively coupled plasma mass spectrometry (ICP-MS), and the results are shown in Table 1.

[0079] Table 1

[0080] According to the data in Table 1, the total content of inorganic element impurities in the methyltrichlorosilane purified by Example 1 is <0.75ppb, indicating that the metal purity of the product has reached the electronic grade and high purity standards.

[0081] Example 2 A purification system for dimethyldichlorosilane is provided for purifying dimethyldichlorosilane products. The purification system includes a reaction complexation unit, a membrane separation unit, and a two-stage distillation purification unit. The reaction complexation unit includes a chlorine-containing auxiliary agent storage device. The membrane separation unit is assembled by assembling membrane modules in series and parallel. The membrane modules include two-dimensional layered membrane structures. The purification system for dimethyldichlorosilane was used to purify dimethyldichlorosilane with a total impurity content >70 ppm. Specific purification methods included: S10. Dimethyldichlorosilane was introduced into a complexation reactor. The total content of metal and non-metal impurities in the dimethyldichlorosilane was >70 ppm. Stirring was started and the speed was adjusted to 200 r / min. The jacket cooling water was turned on to stabilize the material temperature at 30℃. HCl was continuously introduced at a molar ratio of chlorine-containing additive to metal impurities of 3.5:1, and the flow rate of chlorine-containing additive to methylsilane was adjusted to 0.7:1. The reaction was continued for 2.5 h. After the reaction was completed, a primary dimethyldichlorosilane purified solution was obtained. S20. The primary dimethyldichlorosilane purified solution obtained in S10 is passed into a membrane module including a two-dimensional layered membrane. The operating pressure is adjusted to 2.0 MPa, the operating temperature to 30 °C, the flow rate to 0.5 m / s, and the membrane feed rate to 1 kg / h. After membrane filtration, a secondary dimethyldichlorosilane purified solution is obtained. The preparation method of the two-dimensional layered structure membrane is as follows: Using a 0.22 μm aqueous microporous membrane as the substrate and graphene oxide as the layered oxide two-dimensional material, a two-dimensional material aqueous dispersion with a concentration of 5 mg / mL was prepared. Then, urea and citric acid were added at a ratio of 0.1 g / mL, and the mixture was sonicated for 50 min to obtain a mixture. The mixture was poured into a vacuum filtration device, and a concentrated solution of two-dimensional sheet material with a layered structure was obtained after filtration. The solution was vacuum dried at 60°C for 10 h, and after natural exfoliation, a two-dimensional layered structure membrane was obtained. S30. The purified dimethyldichlorosilane solution obtained in S20 is fed into a two-stage distillation column, where it undergoes a primary light component removal process followed by a secondary heavy component removal process to obtain purified dimethyldichlorosilane, specifically as follows: The secondary dimethyldichlorosilane purified solution obtained from S20 was sent to the primary light component removal tower. The system was first evacuated, the tower pressure was adjusted to 30 kPa, the tower top temperature was stabilized at 35℃, the tower bottom temperature was controlled at 52℃, the total condenser was cooled with 5℃ chilled water, and the reflux ratio was set to 15:1. The light component was collected from the top of the tower. The dimethyldichlorosilane enriched solution after light component removal was obtained from the tower bottom. The dimethyldichlorosilane enriched solution after light removal is sent to a secondary heavy removal tower. The system is first evacuated, and the tower pressure is adjusted to 15 kPa, the top temperature is 32°C, the bottom temperature is 48°C, and the reflux ratio is set to 6:1. High-purity product is collected from the top of the tower, and the residual liquid in the bottom of the tower is continuously discharged for further recycling.

[0082] After passing through S10-S30, dimethyldichlorosilane with a total impurity content >50ppm is purified into a high-purity dimethyldichlorosilane product with a total impurity content <1ppb.

[0083] Comparative Example 1 Comparative Example 1 was set up under Example 2. Compared with Example 2, the difference of Comparative Example 1 is that step S10 is not included, while the remaining steps and process parameters are the same as those of Example 2.

[0084] Comparative Example 2 Comparative Example 2 was set up under Example 2. Compared with Example 2, the difference of Comparative Example 2 is that step S20 is not included, while the remaining steps and process parameters are the same as those of Example 2.

[0085] Comparative Example 3 Comparative Example 3 was set up under Example 2. The difference between Comparative Example 3 and Example 2 is that in S20, an existing organic nanofiltration membrane is used, which can be a polyamide or polysulfone composite membrane with a pore size of 0.5nm-1nm, instead of a two-dimensional layered structure membrane. The remaining steps and process parameters are the same as those in Example 2.

[0086] The dimethyldichlorosilane products obtained in the examples and comparative examples were tested using the same methods as in Example 1, and the results are shown in Table 2.

[0087] Table 2

[0088] Analysis of Table 2 shows that the total content of inorganic elemental impurities in the purified dimethyldichlorosilane product of Example 2 is below 0.58 ppb, while the total impurity content in the comparative example is significantly higher. This is because, in Comparative Example 1, due to the lack of a complexation reaction step, a large amount of metal ion impurities in the system may pass through the subsequent layered membrane structure and be difficult to retain. In addition, without the complexation step, the selectivity of the membrane for organic impurities decreases during the subsequent membrane filtration process. This may be due to free metal ions clogging the membrane pores or damaging the membrane charge structure, leading to overall membrane performance degradation; ultimately, this results in an increase in the total impurity content. In Comparative Example 2, the membrane filtration process is missing, and the system after the complexation reaction directly enters the two-stage distillation column. During the distillation process, metal impurities are difficult to volatilize or vaporize; the colloidal or associated structures formed by the metal complexes may be entrained at the vapor-liquid interface; and the metal impurities may undergo complex decomposition or hydrolysis in the high-temperature zone of the reboiler; ultimately, this leads to a significant increase in the total impurity content. In Comparative Example 3, a polyamide-polysulfone composite membrane was used to replace the two-dimensional layered membrane. The composite membrane had a larger pore size, making it difficult to trap impurities with smaller particle sizes. At the same time, the composite membrane lacked an interlayer channel structure and relied solely on the surface layer for separation, without interlayer active sites for coordination adsorption. Furthermore, dimethyldichlorosilane has strong solubility and permeability, which may cause the composite membrane to swell and plasticize, thereby further increasing the pore size. Ultimately, this led to a significant increase in the total impurity content of the product.

[0089] The above analysis shows that the three-step coupling of the purification method disclosed in this invention is irreplaceable. Through the synergy of the three steps, the total impurity content of methylchlorosilane > 1 ppm is reduced to < 1 ppb after purification.

[0090] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. A method for purifying methylchlorosilane, characterized in that, The purification method includes: Methylchlorosilane with a total impurity content >1ppm is fed into a reactor, and a chlorine-containing additive is introduced into the reactor to adjust the system to acidity and carry out a complexation reaction. During the complexation reaction, chloride ions are kept in excess to obtain a primary methylchlorosilane purified solution. The primary methylchlorosilane purified solution is passed into a membrane module including a two-dimensional layered membrane, and after membrane filtration, a secondary methylchlorosilane purified solution is obtained. The two-dimensional layered structure membrane includes nanochannels and interlayer channels, and the surface and interlayer of the two-dimensional layered structure membrane are loaded with active functional groups. The purified secondary methylchlorosilane solution was fed into a two-stage distillation column and subjected to a primary light component removal treatment and a secondary heavy component removal treatment to obtain purified methylchlorosilane. The total impurity content of the purified methylchlorosilane is <1 ppb; In the two-dimensional layered structure film, the pore size of the nanochannels is less than the interlayer spacing of the interlayer channels and ≤ 0.6 nm, wherein the pore size of the nanochannels is 0.25 nm-0.4 nm; The method for preparing the two-dimensional layered membrane includes: Using an aqueous microporous filter membrane as a substrate, a dispersion of two-dimensional materials was prepared, and then oxygen-containing functional components and nitrogen-containing functional components were added sequentially. The mixture was ultrasonically dispersed and then vacuum filtered to obtain a concentrated solution of two-dimensional sheet materials with a layered structure. Nitrogen-containing and oxygen-containing active functional groups are loaded on the surface and between the layers of the two-dimensional sheet material comprising a stacked structure. The concentrated liquid of the two-dimensional sheet material including the layered structure is vacuum dried and cured to obtain the two-dimensional layered structure film.

2. The purification method according to claim 1, characterized in that, The process of feeding methylchlorosilane with a total impurity content greater than 1 ppm into a reactor, introducing a chlorine-containing additive into the reactor to adjust the system to acidity, and carrying out a complexation reaction, while maintaining an excess of chloride ions during the complexation reaction to obtain a primary methylchlorosilane purified solution includes: A chlorine-containing additive is introduced into the reactor, and the molar ratio of the chlorine-containing additive to the metal impurities in the methylchlorosilane is adjusted to 1.2-10:1; The ratio of the flow rate of the chlorine-containing additive to the flow rate of methylsilane is adjusted to 0.05-0.7:1; The reaction time was controlled at 0.5h-4h, the reaction temperature at 10℃-50℃, and the stirring speed at 50r / min-400r / min.

3. The purification method according to claim 1, characterized in that, The chlorine-containing additive is capable of dissociating Cl. - The chlorine-containing substance, which can dissociate to release Cl - Chlorine-containing substances include at least one of hydrogen chloride, tin tetrachloride, and antimony trichloride.

4. The purification method according to claim 1, characterized in that, The dispersion of the two-dimensional material is an aqueous dispersion of layered oxides, and the concentration of the aqueous dispersion of the layered oxides is 1 mg / mL-5 mg / mL. In the step of sequentially adding the oxygen-containing functional component and the nitrogen-containing functional component, the amount of the oxygen-containing functional component added is 0.05 g / mL–0.2 g / mL, and the amount of the nitrogen-containing functional component added is 0.05 g / mL–0.2 g / mL.

5. The purification method according to claim 4, characterized in that, The layered oxide is graphene oxide, layered titanate, or niobate.

6. The purification method according to claim 1, characterized in that, The oxygen-containing functional component includes at least one of citric acid, glycolic acid, polyethylene glycol, and carboxymethyl cellulose; the nitrogen-containing functional component includes at least one of urea, ethylenediamine, polyethyleneimine, and melamine.

7. The purification method according to claim 1, characterized in that, The method for feeding the purified secondary methylchlorosilane solution into a two-stage distillation column, where it undergoes a primary light component removal process and a secondary heavy component removal process to obtain purified methylchlorosilane includes: The tower pressure for the first-stage light component removal process is 25 kPa-55 kPa, the tower top temperature is 10℃-40℃, the tower bottom temperature is 25℃-58℃, and the reflux ratio is 10-15:

1. The pressure of the secondary deweighting treatment tower is 10kPa-40kPa, the top temperature is 15℃-40℃, the bottom temperature is 30℃-55℃, and the reflux ratio is 6-25:

1.

8. A purification system for methylchlorosilane, used to implement the purification method according to any one of claims 1-7, characterized in that, The purification system includes a complexation reaction processing unit, a membrane separation unit, and a two-stage distillation unit; the complexation reaction processing unit includes a chlorine-containing auxiliary agent storage device; the membrane separation unit is assembled from membrane modules connected in series and / or in parallel; the membrane modules include a two-dimensional layered membrane structure; the two-dimensional layered membrane structure is as described in claim 1.

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