A method for synthesizing diiodosilane

Abstract

The application belongs to the technical field of organic synthesis, and provides a synthesis method of diiodosilane. The synthesis method is carried out in a first reactor and a second reactor connected in series. In the first reactor, a first metal chloride, a solvent, dichlorodisilane (DCS) and iodobenzene are added to carry out a pre-reaction. After the pre-reaction, the solvent, DCS and iodobenzene are continuously fed into the first reactor. Meanwhile, the pre-reaction liquid in the first reactor is continuously fed into the second reactor containing a second metal chloride. The first reactor and the second reactor carry out reactions simultaneously. When the volume of the reaction liquid in the second reactor reaches a target liquid level, the reaction liquid in the second reactor is continuously produced and collected to realize continuous preparation of diiodosilane. The synthesis method provided by the application has high conversion rate of DCS.

Description

Technical Field

[0001] This invention relates to the field of organic synthesis technology, and in particular to a method for synthesizing diiodosilane. Background Technology

[0002] Diiodosilane (DIS), as a silicon source for chemical vapor deposition (CVD), can efficiently generate highly reactive silicon radicals under plasma-enhanced conditions. Its significant advantages lie in maintaining a high deposition rate while requiring lower reaction chamber temperatures and offering more controllable pressure operation. As semiconductor devices (especially chips) continue to miniaturize to overcome Moore's Law limitations, the demand for innovative substrate structures is increasingly urgent. DIS, with its excellent adaptability, can achieve vapor deposition on a variety of substrates.

[0003] Currently, there are two methods for synthesizing DIS by domestic and foreign companies: The first method involves reacting benzenesilane with elemental iodine under low temperature and catalytic conditions, using a batch reactor for intermittent preparation. The reaction is strongly exothermic, with the reactant mixing temperature at -50 to -20°C and the reaction temperature at 0 to 30°C. Ethyl acetate is typically used as the catalyst, and the reaction time is 24 to 40 hours. Finally, copper powder is added, filtration is performed, and conventional distillation is used to obtain the target product, diiodosilane, with a purity exceeding 90%. The second method involves reacting iodine metal compounds with chlorosilane using a batch reactor at a temperature of 0 to 50°C for 12 to 18 hours. Subsequent conventional filtration and purification techniques are used to obtain high-purity diiodosilane with a composition of 80.5%.

[0004] Currently, the main drawback of the preparation method of diiodosilane is that the number of side reactions is increased accordingly, and the conversion rate of the main reaction is reduced. Summary of the Invention

[0005] In view of this, the object of the present invention is to provide a method for synthesizing diiodosilane. The synthesis method provided by the present invention has a high conversion rate of dichlorodihydrosilane and achieves the continuous synthesis of diiodosilane.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] This invention provides a method for synthesizing diiodosilane, wherein the synthesis method is carried out in a first reactor and a second reactor connected in series, and includes the following steps:

[0008] (1) Add the first metal chloride, solvent, dichlorosilane and iodobenzene to the first reactor to carry out a pre-reaction;

[0009] (2) After the pre-reaction, solvent, dichlorosilane and iodobenzene are continuously introduced into the first reactor; at the same time, the pre-reaction liquid in the first reactor is continuously fed into the second reactor containing the second metal chloride; the first reactor and the second reactor react simultaneously.

[0010] (3) When the volume of the reaction liquid in the second reactor reaches the target liquid level, the reaction liquid in the second reactor is continuously extracted and collected to realize the continuous preparation of diiodosilane.

[0011] Preferably, the first metal chloride and the second metal chloride independently include one or more of zinc chloride, aluminum chloride and ferric chloride; the particle size of the first metal chloride and the second metal chloride is independently 1~2 mm.

[0012] Preferably, the purity of the dichlorosilane is ≥99.99%, and the purity of the iodobenzene is ≥99.0%; the solvent is n-hexane, and the purity of the n-hexane is ≥99.0%.

[0013] Preferably, in step (1), the dichlorosilane is added in the form of liquid dichlorosilane; during the addition of the dichlorosilane, the temperature of the first reactor is controlled to be 0~10℃ and the pressure is 0.3~0.5MPa.

[0014] Preferably, in step (1), the total volume of the solvent, dichlorosilane and iodobenzene is 70-95% of the effective volume of the first reactor.

[0015] Preferably, in step (1), the molar ratio of dichlorosilane to iodobenzene is 0.5~2.5:1, the volume ratio of dichlorosilane to solvent is 1:2~5, and the mass of the first metal chloride is 0.1~10.0% of the mass of dichlorosilane.

[0016] Preferably, in step (1), the temperature of the pre-reaction is 20~50℃ and the pressure is 0.3~0.5MPa; the pre-reaction is carried out under stirring conditions, the stirring speed is 100~200r / min; and the pre-reaction time is 5~20min.

[0017] Preferably, in step (2), the flow rate of continuously introduced dichlorosilane is 0.5~1.5L / h.

[0018] Preferably, in step (2), the amount of the second metal chloride added is 0.1 to 10.0% of the mass of dichlorosilane that the second reactor can hold.

[0019] Preferably, in step (2), the reaction temperature is 20~50℃ and the pressure is 0.3~0.5MPa.

[0020] This invention provides a method for synthesizing diiodosilane.

[0021] The synthesis method of this invention uses dichlorodihydrosilane (DCS) as the silicon source, iodobenzene as the iodine source, and metal chloride as the catalyst. The reaction conditions are mild and easy to control. Two reactors in series are used for continuous synthesis of diiodosilane. There are few side reactions, and the conversion rate of dichlorodihydrosilane reaches more than 76%. Attached Figure Description

[0022] Figure 1 The present invention provides a flowchart for the synthesis of diiodosilane. Detailed Implementation

[0023] Figure 1 The following is a flowchart of the synthesis of diiodosilane provided by the present invention, in conjunction with... Figure 1 The synthesis method provided by this invention will be described in detail.

[0024] This invention provides a method for synthesizing diiodosilane, wherein the synthesis method is carried out in a first reactor and a second reactor connected in series, and includes the following steps:

[0025] (1) A first metal chloride, solvent, dichlorosilane (DCS) and iodobenzene are added to the first reactor for pre-reaction;

[0026] (2) After the pre-reaction, solvent, dichlorosilane and iodobenzene are continuously introduced into the first reactor; at the same time, the pre-reaction liquid in the first reactor is continuously fed into the second reactor containing the second metal chloride; the first reactor and the second reactor react simultaneously.

[0027] (3) When the volume of the reaction liquid in the second reactor reaches the target liquid level, the reaction liquid in the second reactor is continuously extracted and collected to realize the continuous preparation of diiodosilane.

[0028] Unless otherwise specified, the raw materials used in this invention are preferably commercially available products.

[0029] In this invention, the synthesis method is carried out in a first reactor and a second reactor connected in series. In one specific embodiment of this invention, the volumes of the first reactor and the second reactor are preferably the same. In another specific embodiment of this invention, the volume of both the first reactor and the second reactor is preferably 10L. In this invention, the material of the first reactor is preferably stainless steel, more preferably 316L stainless steel. In this invention, the first reactor is preferably equipped with a mechanical stirrer, the blades of which are preferably three-bladed propellers, and the blades are preferably arranged in multiple layers. In this invention, the exterior of the first reactor is preferably equipped with a temperature control jacket, the internal medium of which is preferably heat transfer oil, and the temperature control range of which is preferably -20~240℃. In this invention, the top of the first reactor is preferably equipped with a nitrogen inlet, a thermometer inlet, a pressure gauge inlet, a sight glass inlet, and a feed inlet. In this invention, the bottom right side of the first reactor is preferably equipped with an outlet pipe, the bottom of which is preferably surrounded by a filter screen, the filter screen is preferably a sintered 316L stainless steel filter screen, and the filtration accuracy of the filter screen is preferably 0.2~0.5mm. In this invention, the material and structure of the second reactor are the same as those of the first reactor, and will not be described again here. In this invention, the first reactor and the second reactor are preferably connected in series via a pipeline. The pipeline preferably connects the first reactor and the second reactor in series by connecting the outlet pipe of the first reactor and the feed port of the second reactor respectively; a valve is preferably installed on the pipeline.

[0030] In this invention, a first metal chloride, a solvent, dichlorosilane, and iodobenzene are added to the first reactor for a pre-reaction.

[0031] In this invention, before adding materials (first metal chloride, solvent, dichlorosilane and iodobenzene) to the first reactor, it is preferable to further include: purging the first reactor with nitrogen. This invention does not specifically limit the time of nitrogen purging, as long as the dew point is qualified, that is, the dew point is <-60°C.

[0032] In this invention, the first metal chloride preferably includes one or more of zinc chloride (ZnCl2), aluminum chloride (AlCl3), and ferric chloride (FeCl3). In this invention, the particle size of the first metal chloride is preferably 1-2 mm. In this invention, the purity of the first metal chloride is preferably 99.5%.

[0033] In this invention, the purity of the dichlorodihydrosilane is preferably ≥99.99%. In this invention, the purity of the iodobenzene is preferably ≥99.0%. In this invention, the solvent is preferably n-hexane. In this invention, the purity of the n-hexane is preferably ≥99.0%. In this invention, using high-purity dichlorodihydrosilane, iodobenzene, and solvent can reduce the occurrence of side reactions.

[0034] In this invention, the total volume of the solvent, dichlorosilane and iodobenzene is preferably 70-95% of the effective volume of the first reactor, specifically preferably 70%, 75%, 80%, 85%, 90%, 91.25%, 92.5% or 95%.

[0035] In this invention, the addition of a first metal chloride, solvent, dichlorosilane and iodobenzene to the first reactor is preferably carried out by sequentially adding the first metal chloride, solvent, dichlorosilane and iodobenzene to the first reactor.

[0036] In this invention, the solvent is preferably added in one step.

[0037] In this invention, the dichlorosilane is preferably added in liquid form. The preferred flow rate for adding the dichlorosilane is 0.5-2 L / h, more preferably 1 L / h. During the addition process, the temperature of the first reactor is preferably controlled at 0-10°C, specifically 0°C or 5°C; the pressure is preferably 0.3-0.5 MPa, specifically 0.3 MPa, 0.4 MPa, or 0.5 MPa. Controlling the temperature of the first reactor to 0-10°C and the pressure to 0.3-0.5 MPa during the addition process promotes the dissolution of dichlorosilane in the solvent, increases its solubility, and thus improves the conversion rate.

[0038] In this invention, the preferred flow rate for adding iodobenzene is 0.5~2 L / h. During the addition of iodobenzene, the temperature of the first reactor is preferably controlled at 0~10℃, specifically 0℃ or 5℃; the pressure is preferably 0.3~0.5 MPa, specifically 0.3 MPa, 0.4 MPa, or 0.5 MPa. Controlling the temperature of the first reactor to 0~10℃ and the pressure to 0.3~0.5 MPa during the addition of iodobenzene helps maintain the high solubility of dichlorosilane in the solvent, thereby improving the contact and reaction between iodobenzene and dichlorosilane, ultimately increasing the conversion rate.

[0039] In this invention, the molar ratio of dichlorosilane to iodobenzene is preferably 0.5 to 2.5:1, specifically preferably 0.5:1, 0.9:1, 0.92:1, 1:1, 1.09:1, 1.1:1, 1.5:1, 2:1, or 2.5:1. In this invention, the mass of the first metal chloride is preferably 0.1% to 10.0% of the mass of dichlorosilane, specifically preferably 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 9.7%, 9.8%, or 10%. In this invention, the volume ratio of dichlorosilane to solvent is preferably 1:2 to 5, specifically preferably 1:2, 1:3, 1:4, or 1:5.

[0040] In this invention, the pre-reaction temperature is preferably 20~50℃, specifically 20℃, 30℃, 40℃ or 50℃; the pressure is preferably 0.3~0.5MPa, specifically 0.3MPa, 0.4MPa or 0.5MPa; the pre-reaction is preferably carried out under stirring conditions, and the stirring speed is preferably 100~200 r / min; the pre-reaction time is preferably 5~20 min, specifically 5 min, 10 min, 15 min or 20 min. In this invention, the pre-reaction is preferably carried out under a protective atmosphere, preferably nitrogen.

[0041] After the pre-reaction, the present invention preferably proceeds directly to subsequent operations without any post-processing.

[0042] After the pre-reaction, the present invention continuously introduces solvent, dichlorosilane and iodobenzene into the first reactor; at the same time, the pre-reaction liquid in the first reactor continuously flows into the second reactor containing the second metal chloride; the first reactor and the second reactor react simultaneously.

[0043] In this invention, the flow rate of continuously introduced dichlorosilane is preferably 0.5~1.5 L / h, more preferably 1 L / h. In this invention, the flow rates of continuously introduced dichlorosilane and continuously introduced iodobenzene preferably result in a molar ratio of continuously introduced dichlorosilane to continuously introduced iodobenzene of 1~5:2, and the flow rates of continuously introduced dichlorosilane and continuously introduced solvent preferably result in a volume ratio of continuously introduced dichlorosilane to continuously introduced solvent of 1:2~5.

[0044] In this invention, the flow rate of the pre-reaction liquid continuously flowing into the second reactor is preferably such that the liquid level in the first reactor is at a high level, which is preferably 65-70% of the total liquid level; the total liquid level refers to the liquid level corresponding to the effective volume of the first reactor.

[0045] In this invention, the amount of the second metal chloride added is preferably 0.1% to 10.0% of the mass of dichlorosilane that the second reactor can hold, specifically preferably 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 9.7%, 9.8%, or 10%. In this invention, the amount of dichlorosilane that the second reactor can hold refers to the amount of dichlorosilane added when the solvent, dichlorosilane, and iodobenzene are introduced into the second reactor at a molar ratio of dichlorosilane to iodobenzene of 1-5:2 and a volume ratio of solvent to dichlorosilane of 2-5:1; and when the total volume of the solvent, dichlorosilane, and iodobenzene is the effective volume of the second reactor. In a specific embodiment of this invention, the amount of the second metal chloride added in the second reactor is preferably the same as the amount of the first metal chloride added in the first reactor.

[0046] In this invention, the reaction temperature is preferably 20~50℃, specifically 20℃, 30℃, 40℃ or 50℃; the pressure is preferably 0.3~0.5MPa, specifically 0.3MPa, 0.4MPa or 0.5MPa; the pre-reaction is preferably carried out under stirring conditions, and the stirring speed is preferably 100~200 r / min. In this invention, the reaction is preferably carried out under a protective atmosphere, preferably nitrogen.

[0047] Once the volume of the reaction liquid in the second reactor reaches the target level, the present invention continuously extracts and collects the reaction liquid in the second reactor to achieve continuous preparation of diiodosilane.

[0048] In this invention, the target liquid level is preferably 65-70% of the total liquid level, where the total liquid level refers to the liquid level corresponding to the effective volume of the second reactor.

[0049] In this invention, the flow rate at which the reaction liquid in the second reactor is continuously collected is preferably such that the liquid level in the second reactor is at a high level, which is preferably 65-70% of the total liquid level, where the total liquid level refers to the liquid level corresponding to the effective volume of the second reactor.

[0050] In this invention, the collected reaction liquid is preferably placed in a reaction product tank.

[0051] In this invention, the collected reaction liquid is preferably subjected to post-treatment, which preferably includes, but is not limited to, atmospheric distillation, vacuum distillation, adsorption purification, sub-boiling distillation, and membrane filtration. This invention does not specifically limit the parameters for atmospheric distillation, vacuum distillation, adsorption purification, sub-boiling distillation, and membrane filtration.

[0052] In this invention, the pre-reaction and reaction processes occur according to the following reaction formulas:

[0053] SiH2Cl2+2C6H5I→SiH2I2+2C6H5Cl.

[0054] As can be seen, no solid is generated before or after the reaction of this invention.

[0055] The following detailed description of the synthesis method of diiodosilane provided by the present invention, in conjunction with the embodiments, should not be construed as limiting the scope of protection of the present invention.

[0056] Example 1

[0057] according to Figure 1 The synthesis flowchart shown illustrates the preparation of diiodosilane, with the following steps:

[0058] First, the first and second reactors (both with a volume of 10L and an effective volume of 8L) were thoroughly purged with nitrogen until the dew point reached -60℃. Then, under nitrogen protection and in a sealed environment, 120g of ZnCl2 powder with a particle size of 2mm and a purity of 99.5% was poured into the feed port, followed by 5L of 99% pure n-hexane. The temperature of the temperature control jacket of the first reactor was set at 5℃ and the pressure at 0.3MPa. High-purity DCS liquid (purity of 99.99%) and iodobenzene (purity of 99.0%) were introduced at a rate of 1L / h, 1L and 1.3L respectively (where the volume ratio of n-hexane to dichlorosilane is 5:1 and the molar ratio of dichlorosilane to iodobenzene is 1:1). Mechanical stirring was started (200r / min), and the temperature of the temperature control jacket of the first reactor was controlled at 30~40℃ and the pressure at 0.4MPa. The pre-reaction was carried out for 10min.

[0059] After the pre-reaction, high-purity DCS liquid, iodine, and n-hexane are continuously introduced into the first reactor according to the following ratio (volume ratio of n-hexane to dichlorosilane is 5:1, molar ratio of dichlorosilane to iodobenzene is 1:1), with the high-purity DCS liquid being introduced at a rate of 1 L / h. Simultaneously, the outlet valve of the first reactor is opened, allowing the pre-reaction liquid in the first reactor to flow into the second reactor. Once the pre-reaction liquid in the second reactor has submerged the mechanical stirrer, the mechanical stirrer is turned on, and the temperature of the temperature control jacket is set to 30~40℃ and the pressure to 0.3MPa. The outflow rate of the pre-reaction liquid in the first reactor is controlled to maintain the liquid level in the first reactor at 70% of the total liquid level. The first and second reactors react simultaneously.

[0060] Once the volume of the reaction liquid in the second reactor reaches the target level (70% of the total liquid level), open the outlet pipe of the second reactor to continuously collect the reaction liquid in the second reactor into the reaction product tank. Control the collection rate to maintain the liquid level in the second reactor at 70% of the total liquid level.

[0061] The material collected in the reaction product tank was analyzed by gas chromatography-mass spectrometry (GC), and the DIS content reached 42.2%, while the DCS conversion rate reached 76.8%.

[0062] Example 2

[0063] according to Figure 1 The synthesis flowchart shown illustrates the preparation of diiodosilane, with the following steps:

[0064] First, the first and second reactors (both with a volume of 10L and an effective volume of 8L) were thoroughly purged with nitrogen until the dew point reached -60℃. Then, under nitrogen protection and in a sealed environment, 120g of FeCl3 powder with a particle size of 1mm and a purity of 99.5% was poured into the feed port, followed by 5L of 99% pure n-hexane. The temperature of the temperature control jacket of the first reactor was set to 0℃ and the pressure to 0.3MPa. High-purity DCS liquid (purity of 99.99%) and iodobenzene (purity of 99.0%) were introduced at a rate of 1L / h, 1L and 1.4L respectively (where the volume ratio of n-hexane to dichlorosilane is 5:1 and the molar ratio of dichlorosilane to iodobenzene is 0.92:1). Mechanical stirring was started (150r / min), and the temperature of the temperature control jacket of the first reactor was controlled at 30~40℃ and the pressure at 0.4MPa. The pre-reaction was carried out for 10min.

[0065] After the pre-reaction, high-purity DCS liquid, iodobenzene, and n-hexane are continuously introduced into the first reactor according to the following ratio (volume ratio of n-hexane to dichlorosilane is 5:1, molar ratio of dichlorosilane to iodobenzene is 0.92:1), with the high-purity DCS liquid being introduced at a rate of 1 L / h. Simultaneously, the outlet valve of the first reactor is opened, allowing the pre-reaction liquid in the first reactor to flow into the second reactor. Once the pre-reaction liquid in the second reactor has submerged the mechanical stirrer, the mechanical stirrer is turned on, and the temperature of the temperature control jacket is set to 30~40℃ and the pressure to 0.3MPa. The outflow rate of the pre-reaction liquid in the first reactor is controlled to maintain the liquid level in the first reactor at 70% of the total liquid level. The first and second reactors react simultaneously.

[0066] Once the volume of the reaction liquid in the second reactor reaches the target level (70% of the total liquid level), open the outlet pipe of the second reactor to continuously collect the reaction liquid in the second reactor into the reaction product tank. Control the collection rate to maintain the liquid level in the second reactor at 70% of the total liquid level.

[0067] The material collected in the reaction product tank was analyzed by gas chromatography-mass spectrometry (GC), and the DIS content reached 43.5%, while the DCS conversion rate reached 77.1%.

[0068] Example 3

[0069] according to Figure 1 The synthesis flowchart shown illustrates the preparation of diiodosilane, with the following steps:

[0070] First, the first and second reactors (both with a volume of 10L and an effective volume of 8L) were thoroughly purged with nitrogen until the dew point reached -60℃. Then, under nitrogen protection and in a sealed environment, 120g of AlCl3 powder with a particle size of 2mm and a purity of 99.5% was poured into the feed port, followed by 5L of 99% pure n-hexane. The temperature of the temperature control jacket of the first reactor was set at 5℃ and the pressure at 0.3MPa. High-purity DCS liquid (purity of 99.99%) and iodobenzene (purity of 99.0%) were introduced at a rate of 1L / h, 1L and 1.2L respectively (where the volume ratio of n-hexane to dichlorosilane is 5:1 and the molar ratio of dichlorosilane to iodobenzene is 1.09:1). Mechanical stirring was started (150r / min), and the temperature of the temperature control jacket of the first reactor was controlled at 30~40℃ and the pressure at 0.5MPa. The pre-reaction was carried out for 5min.

[0071] After the pre-reaction, DCS, iodobenzene, and n-hexane are continuously introduced into the first reactor according to the ratio (volume ratio of n-hexane to dichlorosilane is 5:1, molar ratio of dichlorosilane to iodobenzene is 1.09:1), with a high-purity DCS liquid introduction rate of 1 L / h. Simultaneously, the outlet valve of the first reactor is opened, allowing the pre-reaction liquid in the first reactor to flow into the second reactor. Once the pre-reaction liquid in the second reactor has submerged the mechanical stirrer, the mechanical stirrer is turned on, and the temperature of the temperature control jacket is set to 40~50℃ and the pressure to 0.4MPa. The outflow rate of the pre-reaction liquid in the first reactor is controlled to maintain the liquid level in the first reactor at 70% of the total liquid level. The first and second reactors react simultaneously.

[0072] Once the volume of the reaction liquid in the second reactor reaches the target level (70% of the total liquid level), open the outlet pipe of the second reactor to continuously collect the reaction liquid in the second reactor into the reaction product tank. Control the collection rate to maintain the liquid level in the second reactor at 70% of the total liquid level.

[0073] GC analysis of the material collected in the reaction product tank showed that the DIS content reached 45.8% and the DCS conversion rate reached 78.3%.

[0074] Table 1 shows the GC detection results of the reaction solutions obtained in Examples 1-3.

[0075] Table 1. Main component information of DIS

[0076]

[0077] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for synthesizing diiodosilane, characterized in that, The synthesis method is carried out in a first reactor and a second reactor connected in series, and includes the following steps: (1) Add the first metal chloride, solvent, dichlorosilane and iodobenzene to the first reactor to carry out a pre-reaction; (2) After the pre-reaction, solvent, dichlorosilane and iodobenzene are continuously introduced into the first reactor; at the same time, the pre-reaction liquid in the first reactor is continuously fed into the second reactor containing the second metal chloride; the first reactor and the second reactor react simultaneously. (3) When the volume of the reaction liquid in the second reactor reaches the target liquid level, the reaction liquid in the second reactor is continuously collected to achieve continuous preparation of diiodosilane; The first metal chloride and the second metal chloride independently include one or more of zinc chloride, aluminum chloride, and ferric chloride; In step (1), the molar ratio of dichlorosilane to iodobenzene is 0.5~2.5:1, the volume ratio of dichlorosilane to solvent is 1:2~5, and the mass of the first metal chloride is 0.1~10.0% of the mass of dichlorosilane; the temperature of the pre-reaction is 20~50℃, and the pressure is 0.3~0.5MPa; the pre-reaction is carried out under stirring conditions, the stirring speed is 100~200r / min, and the pre-reaction time is 5~20min. In step (2), the flow rate of dichlorosilane is continuously introduced at 0.5~1.5L / h; the amount of the second metal chloride added is 0.1~10.0% of the mass of dichlorosilane that the second reactor can hold; the temperature of the reaction is 20~50℃ and the pressure is 0.3~0.5MPa.

2. The synthesis method according to claim 1, characterized in that, The particle size of the first metal chloride and the second metal chloride is independently 1~2 mm.

3. The synthesis method according to claim 1, characterized in that, The purity of the dichlorosilane is ≥99.99%, and the purity of the iodobenzene is ≥99.0%; the solvent is n-hexane, and the purity of the n-hexane is ≥99.0%.

4. The synthesis method according to claim 1, characterized in that, In step (1), the dichlorosilane is added in the form of liquid dichlorosilane; during the addition of the dichlorosilane, the temperature of the first reactor is controlled to be 0~10℃ and the pressure is 0.3~0.5MPa.

5. The synthesis method according to claim 1, characterized in that, In step (1), the total volume of the solvent, dichlorosilane and iodobenzene is 70-95% of the effective volume of the first reactor.

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