A method and system for continuous co-production of diphenyldichlorosilane and triphenylchlorosilane

Abstract

The application discloses a kind of continuous co-production diphenyl dichlorosilane and triphenyl chlorosilane method and system, belong to organic silicon monomer synthesis technical field.The method will silicon powder and chlorobenzene direct method synthesis high-temperature gas phase product, after cyclone separation precision filtration dust removal, in turn through cascade condensation, obtain rich one phenyl trichlorosilane stream;It is directly introduced into disproportionation reaction kettle, and aluminium trichloride catalyst is added to carry out disproportionation and redistribution reaction;After reaction, add tertiary butyl alcohol, make aluminium trichloride into solid tertiary butyl alcohol aluminum, and remove by solid-liquid separation;Filtrate is separated by reduced pressure distillation, ultra vacuum distillation, and high-purity diphenyl dichlorosilane and triphenyl chlorosilane are obtained.The process coupling is closely, and heat energy is reasonably utilized, and catalyst treatment is green and environmental protection, and no strong corrosive gas and chlorine-containing wastewater is generated, the yield and selectivity of high value-added phenyl chlorosilane monomer are significantly improved, and the process is continuous and stable, with high degree of automation, suitable for large-scale industrial production.

Description

Technical Field

[0001] This invention relates to the field of organosilicon monomer synthesis technology, specifically to a continuous production method for co-producing high-value diphenyldichlorosilane (Ph2SiCl2, D) and triphenylchlorosilane (Ph3SiCl, T) by directly synthesizing a mixture of phenylchlorosilanes from silicon powder and chlorobenzene, followed by a stepwise condensation separation coupled with catalytic disproportionation. This method is particularly suitable for large-scale industrial continuous production and can achieve seamless integration of the direct synthesis unit and the disproportionation conversion unit, as well as efficient energy utilization. Background Technology

[0002] In the industrial production of organosilicon monomers, the direct method is the mainstream synthesis process for core monomers such as methylchlorosilanes and phenylchlorosilanes. Its core principle is the direct reaction between metallic silicon (silicon powder) and organochlorine compounds (such as chlorobenzene) under the action of a catalyst (such as a copper-based catalyst) to generate a mixture of target phenylchlorosilanes. The main reaction formula for the synthesis of phenylchlorosilanes is: Si + PhCl → PhSiCl3 (M1) + Ph2SiCl2 (D) + Ph3SiCl (T) + byproducts. The byproducts mainly include benzene, silicon tetrachloride (SiCl4), and high-boiling substances (mostly phenyl polychlorinated silane polymers).

[0003] Of the reaction products described above, diphenyldichlorosilane (D) is a key monomer for synthesizing high-end phenyl silicone oils, heat-resistant silicone resins, organosilicon intermediates, and specialty silicone rubbers, and is widely used in electronics, aerospace, and high-end coatings. Triphenylchlorosilane (T) is an important raw material for preparing specialty phenylsilanes, silicon-based coupling agents, and organosilicon-modified materials, and both have significantly higher economic value than monophenyltrichlorosilane (M1). However, due to limitations imposed by the thermodynamic equilibrium and kinetic characteristics of the reaction, M1 typically accounts for 60%–80% of the phenylchlorosilane mixture synthesized directly, while the total selectivity of D and T is only 20%–30%, which cannot meet the industrial demand for high-value-added products.

[0004] To improve the yields of D and T, the M1 enriched in the direct method product is subjected to a catalytic disproportionation or redistribution reaction. The core disproportionation reaction is: 2PhSiCl3 The redistribution reaction of Ph₂SiCl₂ + SiCl₄ is mainly: PhSiCl₃ + Ph₂SiCl₂ Ph3SiCl + SiCl4. If the mixture is condensed separately before reacting, the following drawbacks exist: 1. Serious energy waste: The gaseous products synthesized by the direct method need to be cooled to room temperature before separation, and the enriched M1 needs to be reheated to the disproportionation reaction temperature, resulting in a large amount of heat energy loss, which does not meet the industrial requirements of energy conservation and consumption reduction. 2. Poor process continuity: It is an intermittent operation, which cannot be matched with the upstream continuous direct synthesis process. It has problems such as material accumulation, cumbersome operation, and low production efficiency, making it difficult to achieve large-scale industrial continuous production. 3. Difficulty in controlling product distribution: It is impossible to flexibly control the ratio of D and T, making it difficult to adapt to the needs of different downstream products, and there is still room for improvement in M1 conversion rate and target product selectivity.

[0005] Therefore, developing a phenylchlorosilane disproportionation process that seamlessly integrates with direct synthesis, utilizes energy efficiently, employs environmentally friendly catalyst treatment, and allows for continuous and stable processes with flexible control over product distribution is of significant practical importance and industrial value for enhancing the added value of organosilicon monomers, reducing production costs, and achieving green industrialization. Summary of the Invention

[0006] To address the technical problems in the direct synthesis of phenylchlorosilanes in existing technologies, such as insufficient selectivity of diphenyldichlorosilane (D) and triphenylchlorosilane (T), low yield of high-value-added products, low coupling between the subsequent disproportionation stage and the synthesis stage, serious energy waste, environmentally unfriendly catalyst treatment, poor process continuity, and difficulty in controlling product distribution, this invention provides a novel continuous process. This process utilizes intelligent step-by-step condensation separation of the gaseous products from the direct synthesis, fully leveraging the sensible heat of the materials. The enriched monophenyltrichlorosilane (M1) is directly introduced into a dedicated disproportionation reactor at a suitable temperature. Using catalyst deactivation and separation technology, M1 is directionally converted, ultimately achieving high-yield and high-selectivity co-production of D and T, while simultaneously solving the environmental and operational challenges of existing processes.

[0007] To achieve the above-mentioned technical objectives, the technical solution of the present invention is as follows: A method for the continuous co-production of diphenyldichlorosilane and triphenylchlorosilane includes the following steps: (1) The gaseous product obtained by direct synthesis of silicon powder and chlorobenzene is dusted and then sequentially condensed through the first condenser and the second condenser. The first condenser is used to condense and separate the components with boiling points higher than phenyltrichlorosilane. The second condenser controls the conditions to condense phenyltrichlorosilane and keep the temperature of the outflowing material at 150℃~200℃. (2) The stream of monophenyltrichlorosilane rich in 150℃~200℃ obtained in step (1) is introduced into the disproportionation reactor and aluminum trichloride catalyst is added to carry out the disproportionation reaction; (3) After the disproportionation reaction is completed, the reactants are cooled down, and then tert-butanol is added to convert aluminum trichloride into aluminum tert-butoxide solid. The solid is removed by solid-liquid separation. (4) The liquid obtained in step (3) is distilled to separate diphenyl dichlorosilane and triphenyl chlorosilane products.

[0008] In step (1), the dust removal includes cyclone separation and precision filtration performed sequentially. The cyclone separator has a separation efficiency of ≥98%, and the precision filter has a filtration accuracy of ≤1μm. The silicon powder has a purity of ≥99.0% and a particle size of 50~200 mesh. The chlorobenzene has a purity of ≥99.5%, and the molar ratio of chlorobenzene to silicon powder is 1.2~1.8:1. The direct synthesis reaction is carried out in a fluidized bed reactor at a reaction temperature of 380~450℃ and a reaction pressure of 0.1~0.3MPa. The catalyst is a copper-based catalyst, and the mass ratio of copper powder to silicon powder is 0.02~0.08.

[0009] In step (1), the first condenser is cooled by heat transfer oil, and the gas phase outlet temperature is controlled at 210~230℃; the second condenser is a shell-and-tube condenser, which uses low-temperature heat transfer oil and room-temperature cooling water for temperature control, and controls the liquid phase outlet temperature at 150℃~200℃; the content of phenyltrichlorosilane in the stream rich in phenyltrichlorosilane is ≥85wt%.

[0010] In step (1), the remaining gas phase leaving the second condenser is sent to a multi-tower distillation system to separate and recover chlorobenzene, benzene and silicon tetrachloride. The recovered chlorobenzene is returned to the direct synthesis step to participate in the reaction again.

[0011] In step (2), the amount of aluminum trichloride catalyst added is 0.1% to 5.0% of the mass of the monophenyltrichlorosilane-rich stream, preferably 0.5% to 2.0%; the disproportionation reaction temperature is 100℃ to 250℃, preferably 120℃ to 180℃, and the reaction time is 0.5 to 5 hours, preferably 1 to 4 hours; the disproportionation reaction is carried out under inert gas protection, and the inert gas flow rate is 0.5 to 1.0 times the volume of the reaction system per hour.

[0012] In step (2), the product ratio of diphenyldichlorosilane to triphenylchlorosilane can be controlled by adjusting the disproportionation reaction temperature and the amount of aluminum trichloride catalyst added, with a ratio range of 2:1 to 5:1.

[0013] In step (3), the cooling is to cool the reactants to below 60°C, preferably 30°C to 50°C, at a cooling rate of 5 to 10°C / h; the amount of tert-butanol added is (2.8 to 3.5):1, preferably 3.0 to 3.2:1, based on the molar ratio of tert-butanol to aluminum trichloride; the tert-butanol is added uniformly using a constant pressure dropping funnel at a dropping rate of 0.5 to 1.5 mL / min; after addition, stirring is continued for 0.5 to 2 hours to ensure complete reaction and aging of the precipitate; the solid-liquid separation method is pressure filtration, centrifugation, or sedimentation, preferably pressure filtration, at a filtration pressure of 0.2 to 0.3 MPa.

[0014] Specifically, step (4) includes: first, performing vacuum distillation on the liquid after solid separation, with a vacuum distillation pressure of -0.090 to -0.098 MPa, separating and recovering unreacted monophenyltrichlorosilane and returning it to the disproportionation reaction in step (2), while collecting the diphenyldichlorosilane fraction; then, performing ultravacuum distillation on the bottom of the vacuum distillation vessel, with an ultravacuum distillation absolute pressure of less than 500 Pa, preferably less than 100 Pa, and a distillation temperature of 200 to 220 °C, to obtain triphenylchlorosilane.

[0015] In steps (1) to (4), a PLC control system is used for parameter linkage control, and the temperature, pressure and flow parameters are monitored and adjusted in real time.

[0016] A system for implementing the above method includes a fluidized bed reactor, a dust removal device, a first condenser, a second condenser, a disproportionation reactor, a solid-liquid separation device, and a product refining unit, sequentially connected by pipelines; wherein the liquid phase outlet of the second condenser is connected to the feed inlet of the disproportionation reactor; the dust removal device includes a cyclone separator and a precision filter connected in sequence; the disproportionation reactor is connected to a catalyst continuous feeding device, a cooling device, and a constant pressure dripping funnel; and a PLC control system is also included, which is connected to each device to realize real-time monitoring and control of parameters.

[0017] The product refining unit includes a buffer tank, a vacuum distillation device, an ultra-vacuum distillation device, a diphenyldichlorosilane product storage tank, and a triphenylchlorosilane product storage tank. The buffer tank is connected to the liquid phase outlet of the first condenser, the diphenyltrichlorosilane recovery outlet of the vacuum distillation device, and the feed inlet of the disproportionation reactor, respectively. The vacuum distillation device is connected to the liquid phase outlet of the solid-liquid separation device. The bottom outlet of the vacuum distillation device is connected to the ultra-vacuum distillation device. The product outlet of the ultra-vacuum distillation device is connected to the diphenyldichlorosilane product storage tank and the triphenylchlorosilane product storage tank, respectively. The bottom outlet of the ultra-vacuum distillation device is connected to the incineration system.

[0018] Compared with the prior art, the present invention has the following beneficial effects: 1. High degree of process coupling and energy integration, resulting in significant energy savings: This invention innovatively uses a stepwise condensation process to directly synthesize high-temperature gaseous products from the direct method. The second condenser condenses M1 at 150℃~200℃ and feeds it directly into the disproportionation reactor, making full use of the sensible heat of the material. The material can reach the temperature range required for the disproportionation reaction without additional heating, which can reduce heating energy consumption by 30%~40% compared with existing processes. At the same time, the operation of each unit is seamlessly connected, realizing the energy optimization and integration of the entire process of synthesis, separation, conversion and purification, which is in line with the industrial development trend of energy saving and consumption reduction.

[0019] 2. Significantly improved yield and selectivity of target products, and stable product quality: By directionally converting M1, which accounts for a relatively high proportion of the direct method products, into D and T, the product distribution of the entire process is fundamentally optimized. The conversion rate of M1 can reach 70%~85%, and the total selectivity of D and T can reach 90%~95%. Compared with existing processes, the total yield of target products is increased by 15%~25%. At the same time, by precisely controlling the step-by-step condensation parameters, disproportionation reaction conditions, and catalyst dosage, the product ratio of D and T can be flexibly adjusted to meet the needs of different downstream products. The purity of the products reaches over 99.0%, with no siloxane byproduct contamination, and the product quality is stable and reliable.

[0020] 3. The catalyst treatment process is green, safe, and efficient, achieving resource utilization: The innovative use of tert-butanol as a quencher and converter for aluminum trichloride catalysts results in a mild and controllable reaction with no large release of HCl gas. This completely avoids equipment corrosion, siloxane side reactions, and oil-water emulsification problems associated with traditional water washing processes, improving product purity, yield, and operational safety. The generated aluminum tert-butanol solid is easily and completely removed through mechanical separation and can be recycled as a chemical raw material, achieving resource utilization of the catalyst. No solid waste or chlorine-containing wastewater is generated, resulting in significant environmental benefits and meeting the requirements of green chemical development.

[0021] 4. The process is continuous, stable, and highly automated, making it easy to scale up for industrial applications: From direct synthesis, staged condensation, disproportionation reaction to catalyst separation and product distillation, a complete and efficient continuous process route is formed. The operation of each unit is smoothly connected, and the PLC control system realizes precise linkage control of parameters, reducing manual operation and ensuring stable and reliable operation. The process is adapted to large-scale industrial production, and the equipment specifications can be flexibly adjusted according to capacity requirements. The production efficiency is increased by more than 50% compared with the batch process, reducing production costs and operational intensity.

[0022] 5. High material recycling rate and significant economic benefits: Unreacted chlorobenzene and unconverted M1 are recycled and reused, increasing the raw material utilization rate to over 95% and reducing raw material consumption; at the same time, by-products silicon tetrachloride and aluminum tert-butoxide are recycled and reused, further improving the economic benefits and resource utilization rate of the process. Attached Figure Description

[0023] Figure 1 This is a process flow diagram of the continuous co-production system of diphenyldichlorosilane and triphenylchlorosilane according to the present invention.

[0024] In the diagram, 1-fluidized bed reactor, 2-cyclone separator, 3-precision filter, 4-first condenser, 5-second condenser, 6-multi-tower distillation system, 7-disproportionation reactor, 8-catalyst continuous feeding device, 9-cooling device, 10-constant pressure dropping funnel, 11-solid-liquid separation equipment, 12-reduced pressure distillation tower, 13-ultra-vacuum distillation device, 14-buffer tank, 15-diphenyldichlorosilane product storage tank, 16-triphenylchlorosilane product storage tank. Detailed Implementation

[0025] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] A method for the continuous co-production of diphenyldichlorosilane and triphenylchlorosilane, comprising the steps of: S1. Direct Synthesis and Preliminary Dust Removal: Silicon powder (purity ≥99.0%, particle size 50~200 mesh), chlorobenzene (purity ≥99.5%), and copper-based catalyst (copper powder to silicon powder mass ratio of 0.02~0.08:1) are fed into fluidized bed reactor 1 in a certain proportion. The reaction temperature in the reactor is controlled at 380~450℃, the reaction pressure at 0.1~0.3MPa, and the molar ratio of chlorobenzene to silicon powder at 1.2~1.8:1 for direct synthesis reaction. The generated gaseous product is processed sequentially by cyclone separator 2 (separation efficiency ≥98%) and precision filter (filtration accuracy ≤1μm) to remove the entrained silicon powder and catalyst fine powder, and obtain a high-temperature mixed gas at 280~320℃. This avoids solid impurities from entering the subsequent condensation and reaction units, which would affect the purity of the product and the operation of the equipment.

[0027] S2. Staged condensation and separation: The high-temperature mixed gas obtained in step S1 first enters the first condenser 4, using heat transfer oil as the refrigerant. The gas phase outlet temperature of the first condenser 4 is controlled at 210-230℃. Monophenyltrichlorosilane (M1, boiling point 201℃), diphenyldichlorosilane (D, boiling point 305℃), triphenylchlorosilane (T, boiling point 377℃), and higher-boiling-point phenyl polychlorosilanes are condensed into liquid phase I, which is directly sent to the buffer tank 14 of the subsequent product refining unit to avoid loss of the target product; The condensed gas enters the second condenser 5. The remaining gas mainly consists of low-boiling-point components, including unreacted chlorobenzene (boiling point 132℃), byproduct benzene (boiling point 80.1℃), silicon tetrachloride (boiling point 57.6℃), etc. After condensation, it is sent to the subsequent multi-tower distillation system 6 (including light-weight removal tower and heavy-weight removal tower) for separation and recycling. The recovered chlorobenzene is returned to the fluidized bed reactor 1 to participate in the reaction again, silicon tetrachloride is collected as a byproduct, and benzene is treated to meet emission standards or recycled, realizing material recycling and reducing raw material consumption.

[0028] S3. Catalytic disproportionation reaction: The high-temperature liquid phase stream II (150℃~200℃) obtained in step S2 is directly and continuously fed into the disproportionation reactor 7 (which adopts a jacketed heating / cooling structure, equipped with a high-efficiency stirring device, and a stirring speed of 150~300 r / min). It can approach the disproportionation reaction temperature without additional heating, fully utilizing the sensible heat of the material. Anhydrous aluminum trichloride is continuously added to the reactor at 0.1%~5.0% (preferably 0.5%~2.0%) based on the mass of stream II as a catalyst. The catalyst is added uniformly using a continuous feeding device to avoid excessively high local catalyst concentrations that could exacerbate side reactions. The temperature inside the disproportionation reactor 7 is controlled at 100℃~250℃ (preferably 120℃~180℃), and the reaction pressure is controlled at 0.1~0.2℃. The reaction pressure is MPa, and the reaction time is 0.5 to 5 hours (preferably 1 to 4 hours), which causes M1 to undergo a disproportionation reaction to generate D and silicon tetrachloride, and can further undergo a redistribution reaction to generate T. By adjusting the reaction temperature and the amount of catalyst added, the product ratio of D and T can be flexibly controlled (D:T can be adjusted in the range of 2:1 to 5:1) to meet the needs of different downstream products.

[0029] S4. Decontamination and Separation of Catalyst: After the disproportionation reaction is completed, the reaction mixture is cooled to below 60°C, preferably 30°C~50°C, through a jacket. The cooling rate is controlled at 5~10°C / h to avoid local overcooling caused by excessively rapid cooling, which would affect the subsequent catalyst conversion reaction. This is done under stirring (stirring speed 100~150 rpm). tert-butanol (purity ≥99.0%) is slowly and uniformly added through a constant-pressure dropping funnel 10 at a rate of (r / min). The amount of tert-butanol added is based on the molar ratio of its amount to aluminum trichloride added, which is (2.8~3.5):1 (preferably 3.0~3.2:1). Slow addition ensures a mild and controllable reaction, avoiding intense localized exothermic reactions. The reaction of tert-butanol with aluminum trichloride produces solid aluminum tert-butoxide. This reaction does not release significant HCl gas, and the product, aluminum tert-butoxide, is a white, loose solid that does not easily clump. After the addition is complete, stirring continues for 0.5~2 hours (preferably 1~1.5 hours) to ensure complete reaction and sufficient aging of the precipitate, facilitating subsequent solid-liquid separation. Separation is then achieved through filtration, centrifugation, or sedimentation (preferably pressure filtration, with a filtration pressure of 0.2~0.3 MPa and a filtration rate of 5~10 L / (m²)). 2 The solid aluminum tert-butoxide is completely removed from the reaction mixture by filtration. The filtered solid aluminum tert-butoxide can be recycled as a chemical raw material (such as for the preparation of aluminum-based catalysts, organoaluminum compounds, etc.), realizing the resource utilization of the catalyst without generating solid waste.

[0030] S5. Product Separation and Purification: The clarified filtrate obtained in step S4 is fed into a vacuum distillation column 12, with the distillation pressure controlled at -0.090~-0.098 MPa. First, low-boiling-point silicon tetrachloride and unreacted chlorobenzene are separated as light components. These light components are sent to a multi-tower distillation system 6 for recovery. Then, the temperature is raised to 95~105℃ to separate and recover unconverted M1. The recovered M1 is buffered in a buffer tank 14 and then returned to the disproportionation reactor 7 in step S3 to participate in the reaction again, improving the raw material utilization rate. The temperature is further raised to 135~145℃ to collect the diphenyl dichlorosilane fraction, with a purity ≥99.5%. The bottom product after distillation mainly contains triphenylchlorosilane and a small amount of high-boiling-point substances. This bottom product is transferred to an ultra-vacuum distillation apparatus 13, with the absolute pressure controlled below 500 Pa (preferably below 100 Pa). The distillation temperature is 200~220℃ to collect high-purity triphenylchlorosilane products with a purity ≥99.0%. The high-boiling-point residue at the bottom of the vessel after ultra-vacuum distillation is then subjected to vacuum distillation to recover a small amount of T before being sent to the incineration system for harmless treatment to avoid environmental pollution.

[0031] To improve the stability and automation level of the process, steps S1 to S5 all use a PLC control system for parameter linkage control, which monitors parameters such as temperature, pressure, and flow rate of each unit in real time. Through feedback adjustment, the process parameters are precisely controlled, reducing human error and ensuring the stability of continuous production.

[0032] In step S3, an inert gas (nitrogen or argon) can be introduced into the disproportionation reactor 7 for protection. The inert gas flow rate is 0.5 to 1.0 times the volume of the reaction system per hour to prevent moisture in the air from entering the reaction system and avoid hydrolysis of silane monomers and deactivation of the catalyst.

[0033] In step S2, the second condenser 5 is a high-efficiency shell-and-tube condenser, and the heat exchange area is designed to be 50~200 m² according to the processing capacity. 2 This ensures that the M1 condensation efficiency is ≥95%, reduces the loss of M1 with low-boiling-point gases, and improves the utilization rate of raw materials. Example 1

[0034] This embodiment provides a method for the continuous co-production of diphenyldichlorosilane and triphenylchlorosilane. The system implementing the above method includes a fluidized bed reactor 1, a dust removal device, a first condenser 4, a second condenser 5, a disproportionation reactor 7, a solid-liquid separation device 11, and a product refining unit, which are connected sequentially by pipelines. The liquid phase outlet of the second condenser 5 is connected to the feed inlet of the disproportionation reactor 7. The dust removal device includes a cyclone separator 2 and a precision filter 3 connected in sequence. The disproportionation reactor 7 is connected to a catalyst continuous feeding device 8, a cooling device 9, and a constant pressure dripping funnel 10. The system also includes a PLC control system, which is connected to each piece of equipment to realize real-time monitoring and control of parameters.

[0035] The product refining unit includes a buffer tank 14, a vacuum distillation device, an ultra-vacuum distillation device 13, a diphenyldichlorosilane product storage tank 15, and a triphenylchlorosilane product storage tank 16. The buffer tank 14 is connected to the liquid phase outlet of the first condenser 4, the recovery outlet of the diphenyltrichlorosilane from the vacuum distillation device, and the feed inlet of the disproportionation reactor 7, respectively. The vacuum distillation device is connected to the liquid phase outlet of the solid-liquid separation device 11. The bottom outlet of the vacuum distillation device is connected to the ultra-vacuum distillation device 13. The product outlet of the ultra-vacuum distillation device 13 is connected to the diphenyldichlorosilane product storage tank 15 and the triphenylchlorosilane product storage tank, respectively. The bottom outlet of the ultra-vacuum distillation device 13 is connected to the incineration system.

[0036] The method includes the following steps: (1) Silicon powder with a purity of 99.2% and a particle size of 80~120 mesh, chlorobenzene with a purity of 99.6% and copper powder catalyst (copper powder mass: silicon powder mass: 0.05:1) are continuously fed into fluidized bed reactor 1 at a molar ratio of chlorobenzene to silicon powder of 1.5:1. The reaction temperature in the reactor is controlled at 420℃ and the reaction pressure at 0.2 MPa to carry out direct synthesis reaction. The generated gaseous product (temperature of about 350℃) is treated by cyclone separator 2 (separation efficiency 98.5%) and precision filter 3 (filtration accuracy 0.8μm) to remove the entrained silicon powder and catalyst fine powder to obtain high temperature mixed gas.

[0037] (2) The high-temperature mixed gas first enters the first condenser 4, where the shell side is cooled by heat transfer oil, and the gas phase outlet temperature is controlled at 220℃. The condensed gas yields stream I containing D, T, and high-boiling-point substances, which is then sent to buffer tank 14. The uncondensed gas enters the second condenser 5 (shell-and-tube type, heat exchange area 100 m²). 2 The system employs a combination of low-temperature heat transfer oil and ambient-temperature cooling water for temperature control, maintaining the liquid phase outlet temperature at 180℃ to obtain a M1-rich stream II (M1 content 92 wt%) at approximately 180℃. The remaining gas leaving the second condenser 5 is sent to the multi-tower distillation system 6 to separate and recover chlorobenzene (returned to the fluidized bed reactor 1), silicon tetrachloride (byproduct collection), and benzene (emission compliant).

[0038] (3) Pump the 180℃ material II into the disproportionation reactor 7 preheated to 160℃ at a constant flow rate (1000 kg / h). At the same time, continuously add 0.8% of the mass of anhydrous aluminum trichloride powder of material II into the reactor through the catalyst continuous feeding device 8. Purge with nitrogen (nitrogen flow rate is 0.8 times the volume of the reaction system / hour), control the stirring speed at 200 r / min, and react at 160℃ and 0.15 MPa for 2.5 hours.

[0039] (4) After the reaction is complete, the material is cooled to 45°C at a rate of 8°C / h using cooling device 9. Tert-butanol (purity 99.2%) is slowly added dropwise using constant pressure dropping funnel 10 at a stirring speed of 120 r / min. The molar ratio of AlCl3 to tert-butanol is 1:3.2, and the addition time is about 1 hour. After the addition is complete, stirring is continued at 45°C for 1 hour to ensure the reaction is complete and the precipitate is aged. Then, the mixture is filtered through pressure filtration device 11 (filtration pressure 0.25 MPa, filtration speed 8 L / (m²·min)) to obtain a white solid filter cake (mainly aluminum tert-butoxide, which is recycled) and a clear filtrate.

[0040] (5) The clarified filtrate is sent to the vacuum distillation tower 12, and the distillation pressure is controlled at -0.098 MPa. The low-boiling substances (silicon tetrachloride and chlorobenzene) are first distilled off at 80~100℃ and sent to the multi-tower distillation system 6 for recovery. Then the temperature is raised to 95~100℃, and the fraction M1 (recovery rate 98%) is returned to the buffer tank 14 and then sent to the disproportionation reactor 7 for re-reaction. The temperature is further raised to 135~140℃, and the product D fraction is collected. The purity is tested to be 99.7%. The bottom of the vacuum distillation tower 12 is transferred to the ultra-vacuum distillation device 13, and the absolute pressure is controlled at 40 Pa and the distillation temperature at 210℃. The product T fraction is collected. The purity is tested to be 99.2%.

[0041] Based on M1 entering the disproportionation reaction, the conversion rate is 78%, the total selectivity of D and T is 93%, the D:T ratio is 3.5:1, the process operates stably, there is no release of HCl gas, and no chlorine-containing wastewater is generated. Example 2

[0042] This embodiment provides a method for the continuous co-production of diphenyldichlorosilane and triphenylchlorosilane. The process parameters of Example 1 are adjusted as follows: the fluidized bed reactor 1 has a reaction temperature of 450°C and a reaction pressure of 0.1 MPa, a chlorobenzene to silicon powder molar ratio of 1.2:1, and a copper powder to silicon powder mass ratio of 0.02:1; the first condenser 4 has a gas phase outlet temperature of 210°C; the second condenser 5 has a liquid phase outlet temperature of 170°C, resulting in an M1-enriched stream II at approximately 170°C (M1 content 88 wt%); the disproportionation reactor 7 has a reaction temperature of 120°C and a reaction pressure of 0.1 MPa, with a catalyst addition amount of 2.0% of the mass of stream II, and a reaction time of 4 hours; during catalyst treatment, the temperature is lowered to 30°C, the tert-butanol to AlCl3 molar ratio is 2.8:1, the dropping time is approximately 3 hours, and the stirring time is 1.5 hours; the reduced pressure distillation pressure is -0.098 MPa, and the ultravacuum distillation absolute pressure is 80 Pa.

[0043] The remaining steps were the same as in Example 1. Testing showed that the M1 conversion rate was 82%, the total selectivity of D and T was 91%, the purity of product D was 99.6%, the purity of product T was 99.1%, the D:T ratio was 4.2:1, the recovery rate of recovered M1 was 97.5%, and the recovery rate of aluminum tert-butoxide was 95%. Example 3

[0044] This embodiment provides a method for the continuous co-production of diphenyldichlorosilane and triphenylchlorosilane. The process parameters of Example 1 are adjusted as follows: the fluidized bed reactor 1 has a reaction temperature of 380°C and a reaction pressure of 0.23 MPa, a chlorobenzene to silicon powder molar ratio of 1.8:1, and a copper powder to silicon powder mass ratio of 0.08:1; the first condenser 4 has a gas phase outlet temperature of 230°C; the second condenser 5 has a liquid phase outlet temperature of 190°C, resulting in an M1-enriched stream II (M1 content 90 wt%) at approximately 190°C, without the need for preheating of the disproportionation reactor 7; the disproportionation reactor 7 has a reaction temperature of 180°C and a reaction pressure of 0.2 MPa, with a catalyst addition amount of 0.5% of the mass of stream II, and a reaction time of 1 hour; during catalyst treatment, the temperature is lowered to 50°C, the tert-butanol to AlCl3 molar ratio is 3.5:1, the dropping time is approximately 2 hours, and the stirring time is 0.5 hours; the reduced pressure distillation pressure is -0.090 MPa, and the ultravacuum distillation absolute pressure is 50 Pa.

[0045] The remaining steps were the same as in Example 1. Testing showed that the M1 conversion rate was 70%, the total selectivity of D and T was 94%, the purity of product D was 99.8%, the purity of product T was 99.3%, the D:T ratio was 2.8:1, the recovery rate of M1 was 98.2%, and the heating energy consumption was reduced by 35% compared to Example 1.

[0046] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the preferred embodiments have been described in detail, those skilled in the art can still make appropriate modifications or equivalent substitutions to the solutions of the present invention, and such modifications or substitutions should be considered within the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for the continuous co-production of diphenyldichlorosilane and triphenylchlorosilane, characterized in that... Includes the following steps: (1) The gaseous product obtained by direct synthesis of silicon powder and chlorobenzene is dusted and then sequentially condensed through the first condenser and the second condenser. The first condenser is used to condense and separate the components with boiling points higher than phenyltrichlorosilane. The second condenser controls the conditions to condense phenyltrichlorosilane and keep the temperature of the outflowing material at 150℃~200℃. (2) The stream of monophenyltrichlorosilane rich in 150℃~200℃ obtained in step (1) is introduced into the disproportionation reactor and aluminum trichloride catalyst is added to carry out the disproportionation reaction. (3) After the disproportionation reaction is completed, the reactants are cooled down, and then tert-butanol is added to convert aluminum trichloride into aluminum tert-butoxide solid. The solid is removed by solid-liquid separation. (4) The liquid obtained in step (3) is distilled to separate diphenyl dichlorosilane and triphenyl chlorosilane products.

2. The method according to claim 1, characterized in that: In step (1), the dust removal includes cyclone separation and precision filtration performed sequentially. The cyclone separator has a separation efficiency of ≥98%, and the precision filter has a filtration accuracy of ≤1μm. The silicon powder has a purity of ≥99.0% and a particle size of 50~200 mesh. The chlorobenzene has a purity of ≥99.5%, and the molar ratio of chlorobenzene to silicon powder is 1.2~1.8:

1. The direct synthesis reaction is carried out in a fluidized bed reactor at a reaction temperature of 380~450℃ and a reaction pressure of 0.1~0.3MPa. The catalyst is a copper-based catalyst, and the mass ratio of copper powder to silicon powder is 0.02~0.08:

1.

3. The method according to claim 1, characterized in that: In step (1), the first condenser is cooled by heat transfer oil, and the gas phase outlet temperature is controlled at 210~230℃; the second condenser is a shell-and-tube condenser, and the liquid phase outlet temperature is controlled by a combination of low-temperature heat transfer oil and room temperature cooling water, and the liquid phase outlet temperature is controlled at 150℃~200℃; in the stream rich in monophenyltrichlorosilane, the monophenyltrichlorosilane content is ≥85wt%.

4. The method according to claim 1, characterized in that: In step (1), the remaining gas phase leaving the second condenser is sent to a multi-tower distillation system to separate and recover chlorobenzene, benzene and silicon tetrachloride. The recovered chlorobenzene is returned to the direct synthesis step to participate in the reaction again.

5. The method according to claim 1, characterized in that: In step (2), the amount of aluminum trichloride catalyst added is 0.1% to 5.0% of the mass of the monophenyltrichlorosilane-rich stream; the disproportionation reaction temperature is 100℃ to 250℃, and the reaction time is 0.5 to 5 hours; the disproportionation reaction is carried out under inert gas protection, and the inert gas flow rate is 0.5 to 1.0 times the volume of the reaction system per hour.

6. The method according to claim 1, characterized in that: In step (2), the product ratio of diphenyldichlorosilane and triphenylchlorosilane obtained by the disproportionation reaction is in the range of 2:1 to 5:

1.

7. The method according to claim 1, characterized in that: In step (3), the cooling is to cool the reactants to below 60°C at a rate of 5-10°C / h; the amount of tert-butanol added is (2.8-3.5):1 based on the molar ratio of tert-butanol to aluminum trichloride added; tert-butanol is added uniformly using a constant pressure dropping funnel at a dropping rate of 0.5-1.5 mL / min; after addition, stirring is continued for 0.5-2 hours to ensure complete reaction and aging of the precipitate; the solid-liquid separation method is pressure filtration, centrifugation, or sedimentation, with a filtration pressure of 0.2-0.3 MPa.

8. The method according to claim 1, characterized in that: Step (4) specifically includes: first, the liquid after solid separation is subjected to vacuum distillation at a pressure of -0.090 to -0.098 MPa to separate and recover unreacted monophenyltrichlorosilane and return it to the disproportionation reaction in step (2), while collecting the diphenyldichlorosilane fraction; then, the bottom product of vacuum distillation is subjected to ultravacuum distillation at an absolute pressure of less than 500 Pa and a distillation temperature of 200 to 220 °C to obtain triphenylchlorosilane.

9. A system for implementing the method according to any one of claims 1-8, characterized in that: The system includes a fluidized bed reactor, a dust removal device, a first condenser, a second condenser, a disproportionation reactor, a solid-liquid separation device, and a product refining unit, all connected sequentially via pipelines. The liquid phase outlet of the second condenser is connected to the feed inlet of the disproportionation reactor. The dust removal device includes a cyclone separator and a precision filter connected in sequence. The disproportionation reactor is equipped with a continuous catalyst feeding device, a cooling device, and a constant-pressure dripping funnel. The system also includes a PLC control system, which is connected to each piece of equipment to enable real-time parameter monitoring and control.

10. The system according to claim 9, characterized in that: The product refining unit includes a buffer tank, a vacuum distillation unit, an ultra-vacuum distillation unit, a diphenyldichlorosilane product storage tank, and a triphenylchlorosilane product storage tank. The buffer tank is connected to the liquid phase outlet of the first condenser, the diphenyltrichlorosilane recovery outlet of the vacuum distillation unit, and the feed inlet of the disproportionation reactor, respectively. The vacuum distillation unit is connected to the liquid phase outlet of the solid-liquid separation equipment. The bottom outlet of the vacuum distillation unit is connected to the ultra-vacuum distillation unit. The product outlet of the ultra-vacuum distillation unit is connected to the diphenyldichlorosilane product storage tank and the triphenylchlorosilane product storage tank, respectively. The bottom outlet of the ultra-vacuum distillation unit is connected to the incineration system.

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