Preparation method of electronic-grade methylsilane with high safety and low cost and electronic-grade methylsilane

Abstract

The application discloses a preparation method of electronic-grade methylsilane with high safety and low cost, which comprises the following steps: methyl dichlorosilane is subjected to hydrogen-chlorine atom rearrangement reaction under the action of a catalyst, and the reaction product is separated to obtain electronic-grade methylsilane. The methylsilane is prepared through catalytic hydrogen-chlorine atom rearrangement in one step under the action of the catalyst, no solid by-product is generated, the conversion efficiency is high, the whole system is a closed system, the materials are conveyed in the system through a pump or pressure difference, and the system is easy to be automatically controlled, safe and stable to operate. The production cost is low, and the electronic-grade product meeting the requirements of the semiconductor industry can be easily prepared. The whole process is logical, safe and reliable to operate, the separation and purification of each reaction product is clear and definite, the purification process is simple and efficient, and the electronic-grade methylsilane with a purity of greater than or equal to 99.999% meeting the requirements of the semiconductor industry can be obtained through single-step refining.

Description

Technical Field

[0001] This invention relates to a method for preparing electronic-grade methylsilane, and more particularly to the hydrogen-chlorine atom rearrangement step of methyldichlorosilane. Background Technology

[0002] A research institution conducted preliminary research on the laboratory preparation of methylsilanes, but this was limited to flask reactions and gram-level preparations, and the reaction products were never purified to the electronic grade. For example, Chinese patent CN108285467B proposed a method for preparing hydrosilanes by reducing chlorosilanes. This method produces complex reaction products, resulting in increased impurities in the main hydrosilane product, making it difficult to separate and unsuitable for use as an electronic specialty gas. It fails to meet the basic requirements of the semiconductor industry. Furthermore, the preparation process is highly hazardous and extremely costly, deterring users due to its high price and severely limiting the production and application of methylsilanes, thus hindering the healthy development of the industry.

[0003] Therefore, how to prepare electronic-grade methylsilanes in a way that is both safe and cost-effective is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] To overcome the above-mentioned shortcomings, the purpose of this invention is to provide a safe and low-cost method for preparing electronic-grade methylsilane.

[0005] To achieve the above objectives, the technical solution adopted in this invention is: a method for preparing electronic-grade methylsilane with high safety and low cost, comprising methyldichlorosilane undergoing a hydrogen-chlorine atom rearrangement reaction under the action of a catalyst, and the reaction product being separated and purified to obtain electronic-grade methylsilane.

[0006] The present invention is further configured such that the separation and purification include the following steps:

[0007] (1) The reaction product is purified by initial distillation to obtain light and heavy components;

[0008] (2) The light component is condensed in the first stage to obtain methylchlorosilane. The methylchlorosilane is purified by distillation and then subjected to the hydrogen-chlorine rearrangement reaction again.

[0009] (3) The light component is condensed in two stages to obtain methylsilane, and the methylsilane is purified by distillation to obtain electronic grade methylsilane.

[0010] The present invention is further configured such that: the heavy component is purified by distillation to separate the relatively light component methyldichlorosilane and the relatively heavy component methyltrichlorosilane; the relatively light component methyldichlorosilane is used as a raw material to carry out the hydrochloric rearrangement reaction again.

[0011] A further provision of this invention is that, in step 2, methylchlorosilane, after being purified by distillation, is mixed alone and / or with methyldichlorosilane, and then the hydrochloric rearrangement reaction is carried out again. The byproduct methylchlorosilane and unreacted methyldichlorosilane, after separation by distillation, can be recycled for the hydrochloric atom rearrangement reaction. Furthermore, the byproduct methyltrichlorosilane is a high-value-added organosilicon product. The entire process generates no waste, making it a truly green chemical process with significant economic value.

[0012] A further provision of this invention is that the hydrogen-chlorine atom rearrangement reaction is carried out in a gas-phase reactor, a liquid-phase reactor, and / or a distillation reactor. Depending on the ratio of methyldichlorosilane to methylmonochlorosilane, different reactors (gas-phase, liquid-phase, or distillation) are used to make the reaction more complete and efficient, which is more conducive to controlling the conversion efficiency and purity of methylsilane, controlling the proportion of co-produced byproducts, and significantly reducing production costs.

[0013] A further provision of this invention is that the catalyst is a weakly basic styrene-based anion exchange resin. Preferably, the weakly basic styrene-based anion exchange resin is a macroporous weakly basic styrene-based anion exchange resin.

[0014] The present invention is further configured such that the hydrogen-chlorine atom rearrangement reaction temperature is 50-220°C and the reaction pressure is 0.05-3 MPa.

[0015] The present invention is further configured such that: in step 1, the initial distillation operating pressure is 0.01-1 MPa and the temperature is 5-150°C.

[0016] The present invention is further configured such that: the primary condensation temperature is -25 to 135°C; the distillation operation pressure of the methylchlorosilane is 0.01 to 1 MPa, the temperature is 5 to 135°C, and the condensation temperature is -25 to 135°C;

[0017] The secondary condensation temperature is -70 to 100°C; the distillation operation pressure of methylsilane is 0.01 to 1 MPa, the temperature is -35 to 115°C, and the condensation temperature is -70 to 100°C.

[0018] A further feature of this invention is that the space velocity for the hydrogen-chlorine atom rearrangement reaction is 50–5000 hr. -1 .

[0019] The present invention is further configured such that the hydrogen-chlorine atom rearrangement reaction temperature is 50-220°C and the reaction pressure is 0.05-3 MPa.

[0020] The present invention is further configured such that the operating pressure for the distillation purification of the heavy components is 0.01-1 MPa, the temperature is 35-150°C, and the condensation temperature is 10-20°C.

[0021] The present invention is further configured such that: in the methyldichlorosilane hydrogen-chlorine atom rearrangement reaction, the conversion rate of methyldichlorosilane is 10-100%, and the conversion rate of methylsilane is 5-70%.

[0022] A further feature of this invention is that the yield of electronic-grade methylsilane is ≥95% during the distillation and purification process.

[0023] Methylsilane is prepared by a hydrogen-chlorine atom rearrangement reaction of methyldichlorosilane. The overall conversion rate of methyldichlorosilane is 100%, and the conversion rate of methylsilane is 5-70%. The production cost is low, which makes methylsilane easy to use in a wide range of applications and greatly promotes the development of silicon carbide, a third-generation semiconductor material.

[0024] The present invention also provides a safe and inexpensive electronic-grade methylsilane, which is prepared by the above-described method for preparing a safe and inexpensive electronic-grade methylsilane.

[0025] A further feature of this invention is that the purity of the electronic-grade methylsilane is ≥99.999%.

[0026] Compared with existing technologies, the advantages of this invention are as follows: This invention prepares methylsilane in a one-step reaction by catalytically rearranging hydrogen and chlorine atoms under the action of a catalyst. There are no solid byproducts, the conversion efficiency is high, the entire system is a closed system, and materials are transported within the system by pressure difference via pumps, facilitating fully automated control and ensuring safe and stable operation. Production costs are low, and it is easy to obtain electronic-grade products that meet the requirements of the semiconductor industry. The entire process is logically sound, safe and reliable in operation, and the separation and purification of each reaction product are clear and precise. The purification process is simple and efficient; electronic-grade methylsilane with a purity ≥99.999% meeting semiconductor requirements can be obtained through a single-step purification process. Attached Figure Description

[0027] Figure 1 This is a flowchart illustrating the preparation process of electronic-grade methylsilane with high safety and low cost, as shown in a preferred embodiment of the present invention. Detailed Implementation

[0028] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby providing a clearer and more explicit definition of the scope of protection of the present invention.

[0029] See appendix Figure 1As shown, 10 kg / h of dimethylchlorosilane is fed into the gas-phase hydrochloric rearrangement reaction unit, which is packed with 8000 g of nitrogen-dried and dehydrated IRA93 catalyst. The unit space velocity is 2000 hr. -1 The process involves a hydrochloric rearrangement reaction at an operating pressure of 0.25 MPa and an operating temperature of 75 °C, yielding methylsilane, methylmonochlorosilane, and methyltrichlorosilane. These products are then fed into a primary distillation column for initial separation. The primary distillation column is heated to 70 °C, with the column pressure controlled at 0.01 MPa. The temperature of the first-stage condenser is maintained at 2 °C, and the temperature of the second-stage condenser at -65 °C, maintaining a reflux ratio of 10:1 to achieve stable reflux. After 10 hours of reflux, the product from the first-stage condenser enters the first rectification column, the product from the second-stage condenser enters the second rectification column, and the heavy components collected from the bottom of the columns enter the third rectification column.

[0030] The first distillation column is controlled at a pressure of 0.01 MPa, a bottom temperature of 12°C, and a condensation temperature of 5°C, maintaining a reflux ratio of 20:1 to form a stable reflux. After refluxing for 10 hours, methylchlorosilane is collected, and its purity is found to be 99.91% upon sampling analysis. It is then returned to the hydrochloric rearrangement reaction unit as a raw material.

[0031] The second distillation column was controlled at a pressure of 0.01 MPa, a reboiler temperature of -50°C, and a condensation temperature of -60°C, maintaining a reflux ratio of 15:1 to form a stable reflux. After reflux for 15 hours, methylsilane was collected, and sampling analysis showed a purity of 99.9996%. This was then filled into steel cylinders to obtain electronic-grade methylsilane. The yield of electronic-grade methylsilane in the distillation purification process was 98%.

[0032] The third distillation column is controlled at a pressure of 0.01 MPa, a reboiler temperature of 60°C, and a condensation temperature of 39°C, maintaining a reflux ratio of 20:1 to form a stable reflux. After reflux for 10 hours, methyldichlorosilane is collected from the top of the column, and its purity is 99.98% after sampling analysis. This methyldichlorosilane is returned to the hydrochloric rearrangement reaction unit as a feedstock. Methyltrichlorosilane is collected from the middle of the column, and its purity is 99.96% after sampling analysis. This methyltrichlorosilane is then stored in clean PE containers. Methyltrichlorosilane is a high-value-added organosilicon product and is sold externally.

[0033] The overall conversion rate of methyldichlorosilane is 100%, and the conversion rate of methylsilane is 21%.

[0034] The above embodiments are only for illustrating the technical concept and features of the present invention. Their purpose is to enable those skilled in the art to understand the content of the present invention and implement it. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing electronic-grade methylsilane with high safety and low cost, characterized in that, The method involves a hydrogen-chlorine atom rearrangement reaction of methyldichlorosilane under the action of a catalyst, and the reaction product is separated and purified to obtain electronic-grade methylsilane; the catalyst is a weakly basic styrene-based anion exchange resin; the separation and purification include the following steps: (1) The reaction product is purified by initial distillation to obtain light and heavy components; (2) The light component is condensed in the first stage to obtain methylchlorosilane. The methylchlorosilane is purified by distillation and then subjected to the hydrogen-chlorine rearrangement reaction again. (3) The light component is condensed in two stages to obtain methylsilane, and the methylsilane is purified by distillation to obtain electronic grade methylsilane; The heavy component is purified by distillation to separate the relatively light component methyldichlorosilane and the relatively heavy component methyltrichlorosilane; the relatively light component methyldichlorosilane is used as a raw material to carry out the hydrochloric rearrangement reaction again.

2. The method for preparing electronic-grade methylsilane with high safety and low cost according to claim 1, characterized in that, In step 2, methylchlorosilane is purified by distillation, then mixed alone or / and with methyldichlorosilane, and then the hydrochloric rearrangement reaction is carried out again.

3. The method for preparing electronic-grade methylsilane with high safety and low cost according to claim 2, characterized in that, The hydrogen-chlorine atom rearrangement reaction is carried out in a gas-phase reactor, a liquid-phase reactor, and / or a distillation reactor.

4. The method for preparing electronic-grade methylsilane with high safety and low cost according to claim 3, characterized in that, The hydrogen-chlorine atom rearrangement reaction temperature is 50–220℃, and the reaction pressure is 0.05–3 MPa.

5. The method for preparing electronic-grade methylsilane with high safety and low cost according to claim 4, characterized in that, In step 1, the initial distillation operating pressure is 0.01–1 MPa, and the temperature is 5–150 °C.

6. The method for preparing electronic-grade methylsilane with high safety and low cost according to claim 5, characterized in that, The primary condensation temperature is -25 to 135°C; the distillation operation pressure of the methylchlorosilane is 0.01 to 1 MPa, the temperature is 5 to 135°C, and the condensation temperature is -25 to 135°C; the secondary condensation temperature is -70 to 100°C; the distillation operation pressure of the methylsilane is 0.01 to 1 MPa, the temperature is -35 to 115°C, and the condensation temperature is -70 to 100°C.

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