Continuous production device and process for phenyl chlorosilane

Abstract

The invention relates to the field of fine chemical engineering, and discloses a phenyl chlorosilane continuous production device and process, the production device comprises a reaction mechanism used for performing Grignard reaction; the primary separation mechanism is used for carrying out primary solid-liquid separation on a product generated by the reaction of the reaction mechanism; the second-stage drying and recycling mechanism is used for thoroughly drying the solid separated by the first-stage separation mechanism and recycling liquid; the rectification mechanism is used for separating and purifying the liquid; the process comprises the following steps: S1, Grignard reaction; s2, primary evaporation separation; s3, secondary airflow drying; and S4, performing vacuum rectification. Core working sections such as Grignard reaction, first-stage evaporation separation, second-stage pneumatic drying and vacuum distillation are integrated in series, so that the whole-process closed, continuous and stable operation of phenylchlorosilane production is realized, the problems of batch production and material turnover of a traditional Grignard method are solved, the production efficiency and the automation level are improved, and the production cost is reduced. The large-scale industrial production requirement is met.

Description

Technical Field

[0001] This invention relates to the field of fine chemical technology, specifically to a continuous production apparatus and process for phenylchlorosilane. Background Technology

[0002] Phenylchlorosilanes are an important class of organosilicon compounds, including phenyltrichlorosilane, diphenyldichlorosilane, triphenylchlorosilane, methylphenyldichlorosilane, and methyldiphenylmonochlorosilane. These compounds are key monomers in the preparation of phenyl silicone resins, phenyl silicone oils, and phenyl silicone rubbers, and have significant effects on improving the heat resistance, radiation resistance, chemical stability, and refractive index of organosilicon polymers. Currently, the main synthetic methods for phenylchlorosilanes cover the Grignard process, condensation process, and direct process. The Grignard process typically uses chlorobenzene and magnesium powder to prepare a Grignard reagent, which then reacts with silicon tetrachloride in an organic solvent. The condensation process uses chlorobenzene and trichlorosilane as raw materials, and the reaction takes place in the gas phase at high temperature. The direct process is similar to the industrial production of methylchlorosilane, utilizing silicon powder and chlorobenzene to react at high temperature in the presence of a catalyst.

[0003] However, existing technologies still face a series of challenges in industrial applications. For the Grignard process, traditional operation is typically batch production, and the byproduct magnesium chloride easily forms a viscous paste with the solvent during the reaction, severely hindering solid-liquid separation efficiency, resulting in low solvent recovery rates, and restricting the continuous operation and automation of the entire production process. Furthermore, the traditional Grignard process often uses ether-based organic solvents, posing high safety risks during operation. For the condensation process, the reaction usually needs to be carried out at extreme high temperatures of 550°C to 700°C, resulting in high energy consumption and the potential for thermal decomposition of chlorobenzene, producing carbon deposits and potential carcinogens, affecting product purity and environmental friendliness. This method's dependence on the raw material trichlorosilane also increases costs, and the product variety is limited. The direct process generally requires high temperatures of 400°C to 700°C, which not only consumes a lot of energy but also relies on a large amount of complex copper-based catalysts, increasing process complexity and cost. Moreover, there is still room for improvement in product yield and selectivity for high-value-added products. In summary, existing methods have shortcomings in terms of safety, reaction conditions, raw material utilization, product diversity, production continuity, and automation. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a continuous production apparatus and process for phenylchlorosilanes, which solves the problems of difficulty in continuous production, difficulty in separating by-products, harsh reaction conditions leading to side reactions, catalyst dependence, and poor solvent safety in existing phenylchlorosilane synthesis methods.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a continuous production apparatus for phenylchlorosilane, comprising: A reaction mechanism for carrying out Grignard reactions, the reaction mechanism comprising a reaction vessel, a phenyl magnesium chloride solution dropping tank, a chlorosilane dropping tank, a first condenser of the reaction vessel, and a second condenser of the reaction vessel; The feed inlet of the reactor is connected to the outlet of the phenyl magnesium chloride solution dropper and the chlorosilane dropper, respectively, and the gas phase outlet at the top of the reactor is connected to the inlet of the first condenser and the second condenser of the reactor, respectively. A primary separation mechanism is used to perform preliminary solid-liquid separation on the products generated by the reaction mechanism. The primary separation mechanism includes a vertical vacuum stirred dryer, a first condenser of the dryer, a second condenser of the dryer, and a crude phenylchlorosilane receiving tank. The feed inlet of the vertical vacuum stirring dryer is connected to the material outlet at the bottom of the reactor, the steam outlet at the top of the vertical vacuum stirring dryer is connected to the inlet of the first condenser of the dryer, the outlet of the first condenser of the dryer is connected to the inlet of the second condenser of the dryer, and the outlet at the bottom of the second condenser of the dryer is connected to the inlet of the crude phenylchlorosilane receiving tank. The secondary drying and recovery mechanism is used to thoroughly dry the solids separated by the primary separation mechanism and recover the liquid. The secondary drying and recovery mechanism includes a nitrogen heat exchanger, an airflow drying pipe, a powder collection assembly, a first airflow drying condenser, a second airflow drying condenser, an induced draft fan, a magnesium chloride powder receiving tank, and an airflow drying condensate receiving tank. The inlet of one end of the airflow drying pipe is connected to the solid outlet of the vertical vacuum stirring dryer and to the hot nitrogen outlet of the nitrogen heat exchanger; the outlet of the other end of the airflow drying pipe is connected to the powder collection assembly; the powder collection assembly is connected to the inlet of the magnesium chloride powder receiving tank; the powder collection assembly is connected to the inlet of the magnesium chloride powder receiving tank and to the inlet of the first condenser of the airflow dryer; the outlet of the first condenser of the airflow dryer is connected to the inlet of the second condenser of the airflow dryer, and the gas outlet of the second condenser of the airflow dryer is connected to the inlet of the induced draft fan; the condensate outlets of both the first and second condensers of the airflow dryer are connected to the inlet of the condensate receiving tank of the airflow dryer. A distillation unit is used to separate and purify liquids. The distillation unit includes a crude phenylchlorosilane storage tank, a phenylchlorosilane distillation column, a first condenser of the distillation column, a second condenser of the distillation column, and a receiving tank of the distillation column. The feed inlet at the top of the crude phenylchlorosilane storage tank is connected to the outlet of the crude phenylchlorosilane receiving tank; the outlet at the bottom of the crude phenylchlorosilane storage tank is connected to the feed inlet of the phenylchlorosilane distillation column; the top vapor outlet of the phenylchlorosilane distillation column is connected to the inlet of the first condenser of the distillation column; the outlet of the first condenser of the distillation column is connected to the inlet of the second condenser of the distillation column; the bottom outlet of the second condenser of the distillation column is connected to the inlet of the receiving tank of the distillation column; and the outlet of the gas flow drying condensate receiving tank is connected to the feed inlet of the crude phenylchlorosilane storage tank.

[0006] Preferably, the powder collection assembly includes a cyclone separator and a bag filter connected in series. The inlet of the cyclone separator is connected to the outlet of the airflow drying pipe; the gas outlet of the cyclone separator is connected to the inlet of the bag filter; the solid collection port of the cyclone separator is connected to the inlet of the magnesium chloride powder receiving tank; and the solid collection port of the bag filter is connected to the inlet of the magnesium chloride powder receiving tank.

[0007] A continuous production process for phenylchlorosilane includes the following steps: S1. Grignard reaction: Chlorosilane and phenylchlorosilane tetrahydrofuran solution are added dropwise from chlorosilane dropper and phenyl magnesium chloride solution dropper to the reaction vessel to carry out Grignard reaction. During the reaction, the evaporated gas is condensed by the first condenser and the second condenser of the reaction vessel and then refluxed back to the reaction vessel. After the reaction is completed, a reaction mixture containing phenylchlorosilane and magnesium chloride is obtained. S2. First-stage evaporation and separation: The reaction mixture obtained in step S1 is transported to a vertical vacuum stirred dryer and stirred and evaporated under vacuum and heating conditions. The vaporized tetrahydrofuran and phenylchlorosilane product vapors are condensed sequentially through the first condenser and the second condenser of the dryer. The condensed crude liquid is collected in a phenylchlorosilane crude product receiving tank. At the same time, magnesium chloride salt residue containing a small amount of solvent is obtained in the vertical vacuum stirred dryer. S3. Secondary airflow drying: The magnesium chloride salt residue obtained in step S2 is conveyed from the solid discharge port of the vertical vacuum stirring dryer to the airflow drying pipe, and high-temperature nitrogen heated by a nitrogen heat exchanger is introduced for purging and drying. The dried gas-solid mixture is then separated by a cyclone separator and a bag filter, and the separated dried magnesium chloride powder is collected in a magnesium chloride powder receiving tank. At the same time, the separated gas is condensed by passing it through the first condenser and the second condenser of the airflow dryer to recover the residual liquid and collect it in the airflow dryer condensate receiving tank. S4. Reduced pressure distillation: The crude liquid collected in the crude phenylchlorosilane receiving tank in step S2 and the recovered liquid collected in the gas flow drying condensate receiving tank in step S3 are combined into the crude phenylchlorosilane storage tank. The combined liquid is then pumped into the phenylchlorosilane distillation column for distillation separation under reduced pressure. The vapor phase at the top of the column is condensed sequentially through the first condenser and the second condenser of the distillation column. The tetrahydrofuran fraction and different types of phenylchlorosilane product fractions are collected in the receiving tank of the distillation column in stages.

[0008] Preferably, in step S1, the chlorosilane is silicon tetrachloride or methyltrichlorosilane.

[0009] Preferably, in step S1, the Grignard reaction is carried out at a temperature of 50–90°C and a pressure of 10–150 kPa.

[0010] Preferably, in step S2, the operating temperature of the vertical vacuum stirring dryer is 150-250℃, and the system pressure is -95--99KPa.

[0011] Preferably, in step S3, the temperature of the high-temperature nitrogen gas is 150–250°C, and the pressure during purging and drying is -95–-99 kPa.

[0012] Preferably, in step S4, the bottom temperature of the phenylchlorosilane distillation column is 50–220°C, and the reflux ratio is 1:1–10.

[0013] Preferably, in step S4, the collected phenylchlorosilane product fraction includes phenyltrichlorosilane, diphenyldichlorosilane, and triphenylmonochlorosilane.

[0014] Preferably, in step S1, the concentration of the phenyl magnesium chloride tetrahydrofuran solution is 10-35%; the molar ratio of the phenyl magnesium chloride to the chlorosilane is 1-3:1.

[0015] This invention provides a continuous production apparatus and process for phenylchlorosilane. It has the following beneficial effects: 1. This invention solves the problems of independent processes, material turnover, and difficulty in continuous production in the traditional Grignard process for producing phenylchlorosilane by integrating four core processes in series: Grignard reaction, primary evaporation separation, secondary gas flow drying, and vacuum distillation. It achieves closed-loop, continuous, and stable operation of the entire process from raw material input to product output, thereby significantly improving production efficiency and automation level and meeting the requirements of large-scale industrial production.

[0016] 2. This invention, by employing a low-temperature liquid-phase Grignard reaction pathway, eliminates the need for an external catalyst and uses non-ether tetrahydrofuran as a solvent. This solves the problems of excessively high reaction temperatures in the direct and condensation methods leading to raw material decomposition, carbon deposition, and increased byproducts, as well as the safety hazards associated with the use of ether solvents in the traditional Grignard process. It achieves efficient reaction under mild and safe conditions, thereby improving raw material utilization, overall product yield, and product selectivity, and fundamentally enhancing the inherent safety of the process.

[0017] 3. This invention solves the problem of the formation of a paste-like substance between magnesium chloride and solvent as a byproduct after the traditional Grignard process reaction, which leads to extremely difficult solid-liquid separation and low solvent recovery rate, by adopting a two-stage combined drying system of vertical vacuum stirring dryer and airflow dryer. It achieves rapid and thorough drying of magnesium chloride salt slag and deep solvent recovery, thereby simplifying the post-processing process, improving the economic efficiency of solvent recovery, and obtaining a clean byproduct with higher added value and no organic residue. Attached Figure Description

[0018] Figure 1 This is a plan view of the device of the present invention; Figure 2 This is a flowchart of the process steps of the present invention.

[0019] The components include: 1. Phenyl magnesium chloride solution dropper; 2. Chlorosilane dropper; 3. First condenser of the reactor; 4. Second condenser of the reactor; 5. Reactor; 6. Vertical vacuum stirred dryer; 7. First condenser of the dryer; 8. Second condenser of the dryer; 9. Phenyl chlorosilane crude product receiving tank; 10. Phenyl chlorosilane crude product storage tank; 11. Phenyl chlorosilane distillation column; 12. First condenser of the distillation column; 13. Second condenser of the distillation column; 14. Receiving tank of the distillation column; 15. Nitrogen heat exchanger; 16. Gas flow drying pipe; 17. Cyclone separator; 18. Bag filter; 19. First condenser of the gas flow dryer; 20. Second condenser of the gas flow dryer; 21. Exhaust fan; 22. Magnesium chloride powder receiving tank; 23. Gas flow dryer condensate receiving tank. Detailed Implementation

[0020] The technical solutions in 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 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.

[0021] Please see Figures 1-2 Example 1:

[0022] S1, Grignard reaction: 441 kg of silicon tetrachloride was added to chlorosilane dropping tank 2, and 2080 kg of a 35% phenyl magnesium chloride tetrahydrofuran solution was added to phenyl magnesium chloride solution dropping tank 1. All the silicon tetrachloride in chlorosilane dropping tank 2 was then added to reaction vessel 5, and stirring was started. Phenyl magnesium chloride solution was added dropwise from phenyl magnesium chloride solution dropping tank 1, maintaining the temperature of reaction vessel 5 at 60–80°C and the pressure at 10–60 kPa. The dropping time was 2 hours, and the reaction continued for another 2 hours after the addition was complete.

[0023] S2, First-stage evaporation separation: The reaction liquid in reactor 5 is pumped into vertical vacuum stirred dryer 6, and stirring and heating are started. The temperature of vertical vacuum stirred dryer 6 is maintained at 200-250℃, and the system vacuum is -95 to -99 kPa. The vaporized reaction liquid is condensed by the first condenser 7 and the second condenser 8 of the dryer and collected into the crude phenylchlorosilane receiving tank 9.

[0024] S3, Secondary airflow drying: The salt residue discharged from the vertical vacuum stirring dryer 6 is fed into the airflow drying pipe 16, where high-temperature nitrogen gas heated to 220-240℃ by a nitrogen heat exchanger 15 is introduced for drying. The system vacuum is maintained at -95 to -99 kPa. The dried solid is collected by a cyclone separator 17 and a bag filter 18 into a magnesium chloride powder receiving tank 22, with a total of 1150 kg of dried magnesium chloride salt collected, achieving a recovery rate of 98.4%. The vapor entrained in the airflow is condensed by the first condenser 19 and the second condenser 20 of the airflow dryer and collected in the airflow dryer condensate receiving tank 23.

[0025] S4, Reduced pressure distillation: The liquid from the crude phenylchlorosilane receiving tank 9 and the gas flow drying condensate receiving tank 23 is transferred together to the crude phenylchlorosilane storage tank 10, and then the material is fed into the phenylchlorosilane distillation column 11 for distillation. The temperature of the phenylchlorosilane distillation column 11 is controlled at 80-220℃, the reflux ratio at 1:3, and the system pressure at -95--99 kPa. The vapor phase at the top of the column is condensed by the first condenser 12 and the second condenser 13 of the distillation column and collected in stages in the receiving tank 14. The following are collected sequentially: 1312 kg of tetrahydrofuran (97% recovery); 24 kg of phenyltrichlorosilane (99.0% purity); 528 kg of diphenyldichlorosilane (99.5% purity); and 62 kg of triphenylmonochlorosilane (98.5% purity). The yield, calculated based on silicon tetrachloride, is 92.7%. Example 2:

[0026] S1, Grignard reaction: 373.8 kg of silicon tetrachloride was added to chlorosilane dropping tank 2, and 3640 kg of a 20% phenyl magnesium chloride tetrahydrofuran solution was added to phenyl magnesium chloride solution dropping tank 1. All the silicon tetrachloride in chlorosilane dropping tank 2 was then added to reaction vessel 5, and stirring was started. Phenyl magnesium chloride solution was added dropwise from phenyl magnesium chloride solution dropping tank 1, maintaining the temperature of reaction vessel 5 at 60–80°C and the pressure at 10–60 kPa. The dropping time was 2 hours, and the reaction continued for another 2 hours after the addition was complete.

[0027] S2, First-stage evaporation separation: The reaction liquid in reactor 5 is pumped into vertical vacuum stirred dryer 6, and stirring and heating are started. The temperature of vertical vacuum stirred dryer 6 is maintained at 200-250℃, and the system vacuum is -95 to -99 kPa. The vaporized reaction liquid is condensed by the first condenser 7 and the second condenser 8 of the dryer and collected into the crude phenylchlorosilane receiving tank 9.

[0028] S3, Secondary airflow drying: The salt residue discharged from the vertical vacuum stirring dryer 6 is fed into the airflow drying pipe 16, where high-temperature nitrogen gas heated to 220-240°C by a nitrogen heat exchanger 15 is introduced for drying. The system vacuum is maintained at -95 to -99 kPa. The dried solid is collected in the magnesium chloride powder receiving tank 22 by a cyclone separator 17 and a bag filter 18, with a total of 1076 kg of dried magnesium chloride salt collected, achieving a recovery rate of 97.8%. The vapor entrained in the airflow is condensed in the first condenser 19 and the second condenser 20 of the airflow dryer and collected in the airflow dryer condensate receiving tank 23.

[0029] S4, Reduced pressure distillation: The liquid from the crude phenylchlorosilane receiving tank 9 and the gas flow drying condensate receiving tank 23 is transferred together to the crude phenylchlorosilane storage tank 10, and then the material is fed into the phenylchlorosilane distillation column 11 for distillation. The temperature of the phenylchlorosilane distillation column 11 is controlled at 80-220℃, the reflux ratio at 1:3, and the system pressure at -95--99 kPa. The vapor phase at the top of the column is condensed by the first condenser 12 and the second condenser 13 of the distillation column and collected in stages in the receiving tank 14. The following are collected sequentially: 2830 kg of tetrahydrofuran (97% recovery); 10 kg of phenyltrichlorosilane (99.1% purity); 274 kg of diphenyldichlorosilane (99.2% purity); and 279 kg of triphenylmonochlorosilane (98.8% purity). The yield, calculated based on silicon tetrachloride, is 94.3%. Example 3:

[0030] S1, Grignard reaction: 598 kg of methyltrichlorosilane was added to chlorosilane dropping tank 2, and 2500 kg of a 30% phenyl magnesium chloride tetrahydrofuran solution was added to phenyl magnesium chloride solution dropping tank 1. All the methyltrichlorosilane in chlorosilane dropping tank 2 was then added to reaction vessel 5, and stirring was started. Phenyl magnesium chloride solution was added dropwise from phenyl magnesium chloride solution dropping tank 1, maintaining the temperature of reaction vessel 5 at 70–90°C and the pressure at 20–80 kPa. The dropping time was 3 hours, and the reaction continued for 2 hours after the addition was complete.

[0031] S2, First-stage evaporation separation: The reaction liquid in reactor 5 is pumped into vertical vacuum stirred dryer 6, and stirring and heating are started. The temperature of vertical vacuum stirred dryer 6 is maintained at 200-230℃, and the system vacuum is -95 to -99 kPa. The vaporized reaction liquid is condensed by the first condenser 7 and the second condenser 8 of the dryer and collected into the crude phenylchlorosilane receiving tank 9.

[0032] S3, Secondary airflow drying: The salt residue discharged from the vertical vacuum stirring dryer 6 is fed into the airflow drying pipe 16, where high-temperature nitrogen gas heated to 210-230°C by a nitrogen heat exchanger 15 is introduced for drying. The system vacuum is maintained at -95 to -99 kPa. The dried solid is collected in the magnesium chloride powder receiving tank 22 by a cyclone separator 17 and a bag filter 18, with a total of 1296 kg of dried magnesium chloride salt collected, achieving a recovery rate of 96.1%. The vapor entrained in the airflow is condensed in the first condenser 19 and the second condenser 20 of the airflow dryer and collected in the airflow dryer condensate receiving tank 23.

[0033] S4, Reduced pressure distillation: The liquid from the crude phenylchlorosilane receiving tank 9 and the gas flow drying condensate receiving tank 23 is transferred together to the crude phenylchlorosilane storage tank 10, and then the material is fed into the phenylchlorosilane distillation column 11 for distillation. The temperature of the phenylchlorosilane distillation column 11 is controlled at 80-200℃, the reflux ratio at 1:4, and the system pressure at -95--99 kPa. The vapor phase at the top of the column is condensed by the first condenser 12 and the second condenser 13 of the distillation column and collected in stages in the receiving tank 14. The following are collected sequentially: 1673 kg of tetrahydrofuran (95.6% recovery rate); 465 kg of methylphenyldichlorosilane (99.4% purity); and 314 kg of methyldiphenylmonochlorosilane (99.5% purity). The yield, calculated based on methyltrichlorosilane, is 94.5%. Example 4:

[0034] S1, Grignard reaction: 747.5 kg of methyltrichlorosilane was added to chlorosilane dropping tank 2, and 3000 kg of a 25% phenyl magnesium chloride tetrahydrofuran solution was added to phenyl magnesium chloride solution dropping tank 1. All the methyltrichlorosilane in chlorosilane dropping tank 2 was then added to reaction vessel 5, and stirring was started. Phenyl magnesium chloride solution was added dropwise from phenyl magnesium chloride solution dropping tank 1, maintaining the temperature of reaction vessel 5 at 60–90°C and the pressure at 10–70 kPa. The dropping time was 3 hours, and the reaction continued for another 3 hours after the addition was complete.

[0035] S2, First-stage evaporation separation: The reaction liquid in reactor 5 is pumped into vertical vacuum stirred dryer 6, and stirring and heating are started. The temperature of vertical vacuum stirred dryer 6 is maintained at 200-220℃, and the system vacuum is -97 to -99 kPa. The vaporized reaction liquid is condensed by the first condenser 7 and the second condenser 8 of the dryer and collected into the crude phenylchlorosilane receiving tank 9.

[0036] S3, Secondary airflow drying: The salt residue discharged from the vertical vacuum stirring dryer 6 is fed into the airflow drying pipe 16, where high-temperature nitrogen gas heated to 210-250°C by a nitrogen heat exchanger 15 is introduced for drying. The system vacuum is maintained at -95 to -99 kPa. The dried solid is collected in the magnesium chloride powder receiving tank 22 by a cyclone separator 17 and a bag filter 18, with a total of 1458 kg of dried magnesium chloride salt collected, achieving a recovery rate of 97.4%. The vapor entrained in the airflow is condensed in the first condenser 19 and the second condenser 20 of the airflow dryer and collected in the airflow dryer condensate receiving tank 23.

[0037] S4, Reduced pressure distillation: The liquid from the crude phenylchlorosilane receiving tank 9 and the gas flow drying condensate receiving tank 23 is transferred together to the crude phenylchlorosilane storage tank 10, and then the material is fed into the phenylchlorosilane distillation column 11 for distillation. The temperature of the phenylchlorosilane distillation column 11 is controlled at 80-200℃, the reflux ratio at 1:2.5, and the system pressure at -95--99 kPa. The vapor phase at the top of the column is condensed by the first condenser 12 and the second condenser 13 of the distillation column and collected in stages in the receiving tank 14. 2164 kg of tetrahydrofuran (96.2% recovery rate), 832 kg of methylphenyldichlorosilane (99.7% purity), and 103 kg of methyldiphenylmonochlorosilane (99.1% purity) are collected sequentially. The yield, calculated based on methyltrichlorosilane, is 95.9%.

[0038] Comparative Example 1: Objective: To simulate the traditional Grignard process, which suffers from problems such as the formation of a paste-like byproduct MgCl2 with the solvent, difficulty in separation, low solvent recovery rate, and inability to produce continuously.

[0039] Process steps: Grignard reaction: In a 1000L jacketed reactor, 441 kg of silicon tetrachloride was added. 2080 kg of a 35% phenyl magnesium chloride tetrahydrofuran solution was slowly added dropwise, with the reactor temperature controlled at 60–80°C using cooling water from the jacket. The addition process took 2 hours, and after completion, the reaction was stirred for another 2 hours, yielding a viscous reaction mixture containing phenylchlorosilane and magnesium chloride.

[0040] Solid-liquid separation: The viscous mixture was pumped to a plate and frame filter press for solid-liquid separation. Due to the paste-like consistency of the material, the filtration process was extremely slow, and the filter cake had a high liquid content. To improve the yield, approximately 400 kg of tetrahydrofuran was used to wash and press the filter cake three times. The entire separation and washing process took about 8 hours, and due to the open solvent operation, significant solvent evaporation occurred.

[0041] Merging and distillation: The mother liquor obtained from the first filtration and the washing liquid obtained from the third washing were combined to obtain a crude phenylchlorosilane solution. This solution was then pumped into a distillation column for vacuum distillation, with the column bottom temperature controlled at 80–220°C, a reflux ratio of 1:3, and a system pressure of -95 to -99 kPa.

[0042] result: Ultimately, 1050 kg of tetrahydrofuran was collected, with a recovery rate of only 77.8%. 18 kg of phenyltrichlorosilane, 435 kg of diphenyldichlorosilane, and 41 kg of triphenylmonochlorosilane were obtained. Based on silicon tetrachloride, the total product yield was only 78.5%. The entire process could not be carried out continuously, was labor-intensive, resulted in high solvent loss, and was difficult to process the filter cake.

[0043] Comparative Example 2: Objective: To simulate the direct method, which suffers from problems such as high reaction temperature, large catalyst dosage, and low proportion of high-value diphenyldichlorosilane in the product.

[0044] Process steps: Catalyst preparation: 70 kg of industrial silicon powder and 30 kg of copper powder (copper powder accounts for 30% of the total mass of the catalyst) are mixed evenly in a mixer to obtain a silicon-copper catalyst. The catalyst is then loaded into a fluidized bed reactor and heated to the reaction temperature.

[0045] Gas-phase catalytic reaction: After being vaporized, chlorobenzene liquid is fed into a fluidized bed reactor. The reactor temperature is controlled at 520℃, and the reaction is carried out under normal pressure. The reaction tail gas is condensed in a condenser, and the crude liquid product is collected.

[0046] Reduced pressure distillation: The collected crude liquid product is pumped into a distillation column for vacuum distillation to separate and recover unreacted chlorobenzene, and phenylchlorosilane products of different components are collected in segments.

[0047] result: Analysis showed that the single-pass conversion rate of chlorobenzene was 61.5%, and the overall selectivity of phenylchlorosilanes was 68.2%. In the final products, the mass ratio (D / T) of diphenyldichlorosilane to phenyltrichlorosilane was only 0.8:1, indicating a low yield of the high-value diphenyldichlorosilane. The reaction process required temperatures above 500°C, resulting in significant energy consumption, and the reactor was prone to carbon buildup.

[0048] Comparative Example 3: Objective: To simulate the condensation method, which has problems such as extremely high reaction temperature, special raw materials (trichlorosilane), and single product.

[0049] Process steps: Gas-phase reaction: The raw materials chlorobenzene and trichlorosilane (SiHCl3) are separately vaporized, mixed in a certain molar ratio, and then introduced into a tubular reactor filled with quartz sand. The reactor temperature is controlled at 600℃ to carry out the gas-phase condensation reaction.

[0050] Product quenching and collection: The high-temperature gas mixture after the reaction is rapidly passed through a quencher and cooled to room temperature with a low-temperature circulating liquid. The condensed crude liquid product is collected. The uncondensed tail gas (mainly HCl) is treated by alkaline absorption.

[0051] Reduced pressure distillation: The collected crude liquid product is pumped into a distillation column for vacuum distillation to separate the product.

[0052] result: The final product is almost entirely phenyltrichlorosilane, with no diphenyldichlorosilane or triphenylmonochlorosilane obtained. The conversion rate of chlorobenzene is low, and severe carbon buildup occurs on the pipe walls at 600°C, along with the detection of byproducts such as polychlorinated biphenyls (PCBs), preventing the process from operating stably for extended periods. This method is not only extremely energy-intensive but also produces only a limited variety of products, restricting its application.

[0053] Comparative Experiment 1: Experimental description: This comparative experiment aims to verify the effectiveness of the process and apparatus of this invention in solving the technical problems of magnesium chloride gelatinization, solid-liquid separation difficulties, and the inability to achieve continuous production in the traditional Grignard process. Both experiments used the same raw material types and feed ratios as in Example 1; the core difference lies in the post-processing and separation methods of the reaction products.

[0054] Example 1: The procedure was carried out according to the steps of Example 1 above. After the Grignard reaction was completed, the reaction mixture was conveyed to the vertical vacuum stirred dryer 6 of the primary separation unit. After preliminary separation of solvent and product by high-temperature evaporation, the resulting magnesium chloride salt residue containing a small amount of solvent was conveyed to the airflow drying pipe 16 of the secondary drying and recovery unit for thorough drying and solvent recovery. The entire process involved continuous material conveying and a closed system.

[0055] Comparative Example 1: The Grignard reaction procedure was the same as in Example 1. After the reaction, a high-viscosity paste containing a magnesium chloride-tetrahydrofuran complex was obtained in the reactor. This material was transferred to a plate and frame filter press by pumping, and solid-liquid separation was performed under pressure. Due to the high viscosity of the material, the filtration speed was slow, and the filter cake had a high liquid content. To improve the product recovery rate, approximately 400 kg of tetrahydrofuran was used to wash and filter the filter cake in stages. The separation and washing operations were intermittent, and some steps were open or semi-open operations (details of the experimental data are shown in Table 1).

[0056] Experimental data: Table 1

[0057] In summary, the innovative mechanism of this invention lies in the use of a two-stage drying system that combines primary evaporation separation with secondary airflow drying, which fundamentally changes the physical form and separation method of magnesium chloride, a byproduct of the Grignard reaction.

[0058] The test data in Table 1 clearly confirms the effectiveness of this mechanism. In Comparative Example 1, the solvate formed by magnesium chloride and tetrahydrofuran caused the material to be in a paste-like state. When separated by traditional pressure filtration, the process took as long as 8.3 hours, and the high liquid retention of the filter cake resulted in a solvent recovery rate of only 77.8%, which directly led to a decrease in the total product yield to 78.5%.

[0059] In contrast, the vertical vacuum stirred dryer in Example 1 of this invention directly disrupts the structure of the magnesium chloride-tetrahydrofuran complex under high temperature and vacuum, vaporizing and separating most of the solvent and product. The salt residue entering the airflow dryer is then further dried by high-temperature nitrogen, achieving deep recovery of the residual solvent. This process shortens the solid-liquid separation time to 2.9 hours, increases the solvent recovery rate to 97.1%, and correspondingly increases the total product yield to 92.7%. Simultaneously, the obtained byproduct, magnesium chloride, is a dry powder, which not only has a high recovery rate (98.4%) but is also easy to transport and utilize.

[0060] In summary, the process design of this invention successfully solves the technical problem of magnesium chloride gelatinization and separation, realizes continuous production, and improves production efficiency, raw material utilization and product yield.

[0061] Comparative Experiment 2: Experimental description: This comparative experiment aims to evaluate the differences between the liquid-phase Grignard process of this invention and the existing high-temperature gas-solid phase catalytic direct method in terms of reaction conditions, catalyst dependence, feedstock utilization, and product selectivity. Example 1:

[0062] The reaction was carried out according to the steps of Example 1 above. The reaction was conducted in the liquid phase at 60–80°C without the use of any external catalyst. The reaction progress and product distribution were controlled by adjusting the molar ratio of the reactants.

[0063] Comparative Example 2: A fluidized bed reactor was used. Industrial silicon powder and copper powder were mixed at a mass ratio of 7:3 to prepare a silicon-copper catalyst, which was then loaded into the reactor. Chlorobenzene was vaporized and introduced into the reactor. The gas-solid phase catalytic reaction was carried out at a controlled reactor temperature of 520℃ and atmospheric pressure. The reaction products were separated by condensation and distillation to obtain the target product (details are shown in Table 2).

[0064] Experimental data: Table 2

[0065] In summary, the innovative mechanism of this invention lies in the use of a low-temperature liquid-phase non-catalytic Grignard reaction pathway, which replaces the high-temperature gas-solid phase catalytic reaction pathway relied upon by the direct method.

[0066] The test data in Table 2 clearly reflect the differences in results resulting from the two different mechanisms. The reaction temperature of the process in this invention is only 60-80℃, which significantly reduces energy consumption compared to the high temperature of 520℃ required in Comparative Example 2, and fundamentally avoids side reactions such as thermal decomposition of chlorobenzene and carbon deposition at high temperatures. Furthermore, this invention does not use a catalyst, simplifying the process and avoiding a series of complex technical problems in the direct method, such as catalyst preparation, activation, deactivation, and regeneration.

[0067] In terms of reaction efficiency and product performance, data show that the chlorobenzene conversion rate and phenylchlorosilane selectivity of this invention are much higher than those of the direct method, resulting in a total product yield of 92.7%, which is superior to the 58.3% of Comparative Example 2. More importantly, through stoichiometric control, this invention achieves a much higher yield of the high-value-added product diphenyldichlorosilane than phenyltrichlorosilane, with a diphenyldichlorosilane / phenyltrichlorosilane mass ratio (D / T) as high as 22.0, while the direct method has limited product distribution control capabilities, with a D / T of only 0.82.

[0068] Therefore, by changing the reaction mechanism, this invention not only achieves milder and simpler production conditions, but also significantly improves the utilization rate of raw materials, the total yield of products, and the selectivity of the target product.

[0069] Comparative Experiment 3: Experimental description: This comparative experiment aims to verify the advantages of the process of the present invention over the harsh high-temperature gas-phase condensation method in terms of reaction conditions, operational safety, raw material versatility, and product diversity. Example 1:

[0070] The procedure was carried out according to the steps of Example 1 above. Silicon tetrachloride and phenyl magnesium chloride were used as raw materials, and a Grignard reaction was carried out under low-temperature liquid phase conditions of 60-80°C. The entire system was operated in a closed system under negative pressure.

[0071] Comparative Example 3: A tubular reactor was used. Chlorobenzene and trichlorosilane (SiHCl3) were separately vaporized and then mixed, and the mixture was introduced into a reactor filled with quartz sand. The reactor temperature was controlled at 600℃ for the gas-phase condensation reaction. The reaction products were quenched, collected, and separated by distillation (see Table 3 for comparison details).

[0072] Experimental data: Table 3

[0073] In summary, this invention achieves the transfer of phenyl functional groups to silicon atoms through a low-temperature liquid-phase Grignard reaction in a closed system. Comparative Example 3, on the other hand, utilizes a gas-phase condensation reaction driven by extreme high temperatures in an open system.

[0074] The test data in Table 3 confirms the significant differences between the two mechanisms in engineering applications. The reaction temperature (60-80℃) of the process in this invention is much lower than the 600℃ required in Comparative Example 3. This not only significantly reduces energy consumption but also fundamentally avoids the thermal decomposition of chlorobenzene at high temperatures, thereby eliminating the formation of carbon deposits and carcinogenic polychlorinated biphenyls (PCBs) and ensuring the cleanliness and long-term operational stability of the process (continuous operation for more than 720 hours).

[0075] In terms of products, this invention has the capability to produce a variety of phenylchlorosilanes, which can be flexibly adjusted according to market demand. In contrast, Comparative Example 3 has a single reaction pathway, producing only phenyltrichlorosilane, which severely limits its application range. Furthermore, this invention does not use conventional flammable and explosive ether solvents and operates under negative pressure, making its inherent safety significantly superior to the high-temperature, high-pressure gas-phase reaction of Comparative Example 3.

[0076] In summary, the reaction mechanism adopted in this invention has decisive advantages in terms of reaction conditions, operational safety, control of side reactions, and product diversity, and is a process route that is more suitable for large-scale, high-quality, safe and stable production.

Claims

1. A continuous production apparatus for phenylchlorosilane, characterized in that, include: The reaction mechanism is used to carry out the Grignard reaction, and the reaction mechanism includes a reaction vessel (5), a phenyl magnesium chloride solution dropper (1), a chlorosilane dropper (2), a first condenser of the reaction vessel (3), and a second condenser of the reaction vessel (4). The inlet of the reactor (5) is connected to the outlet of the phenyl magnesium chloride solution dropper (1) and the chlorosilane dropper (2), respectively. The gas phase outlet at the top of the reactor (5) is connected to the inlet of the first condenser (3) and the second condenser (4) of the reactor, respectively. The primary separation mechanism is used to perform preliminary solid-liquid separation on the products generated by the reaction mechanism. The primary separation mechanism includes a vertical vacuum stirring dryer (6), a first condenser of the dryer (7), a second condenser of the dryer (8), and a crude phenylchlorosilane receiving tank (9). The feed inlet of the vertical vacuum stirring dryer (6) is connected to the material outlet at the bottom of the reactor (5), the steam outlet at the top of the vertical vacuum stirring dryer (6) is connected to the inlet of the first condenser (7) of the dryer, the outlet of the first condenser (7) of the dryer is connected to the inlet of the second condenser (8) of the dryer, and the outlet at the bottom of the second condenser (8) of the dryer is connected to the inlet of the crude phenylchlorosilane receiving tank (9). The secondary drying and recovery mechanism is used to thoroughly dry the solids separated by the primary separation mechanism and recover the liquid. The secondary drying and recovery mechanism includes a nitrogen heat exchanger (15), an airflow drying pipe (16), a powder collection assembly, an airflow drying first condenser (19), an airflow drying second condenser (20), an induced draft fan (21), a magnesium chloride powder receiving tank (22), and an airflow drying condensate receiving tank (23). The feed inlet at one end of the airflow drying pipe (16) is connected to the solid discharge port of the vertical vacuum stirring dryer (6) and to the hot nitrogen outlet of the nitrogen heat exchanger (15); the outlet at the other end of the airflow drying pipe (16) is connected to the powder collection assembly; the powder collection assembly is connected to the inlet of the magnesium chloride powder receiving tank (22); the powder collection assembly is connected to the inlet of the magnesium chloride powder receiving tank (22) and to the inlet of the first airflow drying condenser (19); the outlet of the first airflow drying condenser (19) is connected to the inlet of the second airflow drying condenser (20), and the gas outlet of the second airflow drying condenser (20) is connected to the inlet of the induced draft fan (21); the condensate outlets of the first airflow drying condenser (19) and the second airflow drying condenser (20) are both connected to the inlet of the airflow drying condensate receiving tank (23). A distillation unit for separating and purifying liquids, the distillation unit comprising a crude phenylchlorosilane storage tank (10), a phenylchlorosilane distillation column (11), a first condenser (12) of the distillation column, a second condenser (13) of the distillation column, and a receiving tank (14) of the distillation column. The feed inlet at the top of the crude phenylchlorosilane storage tank (10) is connected to the outlet of the crude phenylchlorosilane receiving tank (9); the outlet at the bottom of the crude phenylchlorosilane storage tank (10) is connected to the feed inlet of the phenylchlorosilane distillation column (11); the top vapor outlet of the phenylchlorosilane distillation column (11) is connected to the inlet of the first condenser (12) of the distillation column; the outlet of the first condenser (12) of the distillation column is connected to the inlet of the second condenser (13) of the distillation column; the outlet at the bottom of the second condenser (13) of the distillation column is connected to the inlet of the receiving tank (14) of the distillation column; and the outlet of the gas flow drying condensate receiving tank (23) is connected to the feed inlet of the crude phenylchlorosilane storage tank (10).

2. The continuous production apparatus for phenylchlorosilane according to claim 1, characterized in that, The powder collection assembly includes a cyclone separator (17) and a bag filter (18) connected in series. The inlet of the cyclone separator (17) is connected to the outlet of the airflow drying pipe (16); the gas outlet of the cyclone separator (17) is connected to the inlet of the bag filter (18); the solid collection port of the cyclone separator (17) is connected to the inlet of the magnesium chloride powder receiving tank (22); the solid collection port of the bag filter (18) is connected to the inlet of the magnesium chloride powder receiving tank (22).

3. A continuous production process for phenylchlorosilanes, comprising a continuous production apparatus for phenylchlorosilanes according to any one of claims 1-2, characterized in that, Includes the following steps: S1. Grignard reaction: Chlorosilane and phenylchlorosilane tetrahydrofuran solution are added dropwise from chlorosilane dropper (2) and phenyl magnesium chloride solution dropper (1) into reaction vessel (5) to carry out Grignard reaction. During the reaction, the evaporated gas is condensed by the first condenser (3) and the second condenser (4) of the reaction vessel and then returned to the reaction vessel (5). After the reaction is completed, a reaction mixture containing phenylchlorosilane and magnesium chloride is obtained. S2, First-stage evaporation and separation: The reaction mixture obtained in step S1 is transported to a vertical vacuum stirring dryer (6) and stirred and evaporated under vacuum and heating conditions. The vaporized tetrahydrofuran and phenylchlorosilane product vapors are condensed sequentially through the first condenser (7) and the second condenser (8) of the dryer. The condensed crude liquid is collected in a phenylchlorosilane crude product receiving tank (9). At the same time, magnesium chloride salt residue containing a small amount of solvent is obtained in the vertical vacuum stirring dryer (6). S3. Secondary airflow drying: The magnesium chloride salt residue obtained in step S2 is conveyed from the solid discharge port of the vertical vacuum stirring dryer (6) to the airflow drying pipe (16), and high-temperature nitrogen heated by the nitrogen heat exchanger (15) is introduced for purging and drying. The dried gas-solid mixture is separated by passing through a cyclone separator (17) and a bag filter (18) in sequence, and the separated dried magnesium chloride powder is collected in a magnesium chloride powder receiving tank (22). At the same time, the separated gas is condensed by passing through the first airflow dryer (19) and the second airflow dryer (20) in sequence to recover the residual liquid and collect it in the airflow dryer condensate receiving tank (23). S4. Reduced pressure distillation: The crude liquid collected in the crude phenylchlorosilane receiving tank (9) in step S2 and the recovered liquid collected in the gas flow drying condensate receiving tank (23) in step S3 are combined into the crude phenylchlorosilane storage tank (10). The combined liquid is then pumped into the phenylchlorosilane distillation column (11) and distilled under reduced pressure. The gas phase at the top of the column is condensed sequentially through the first condenser (12) and the second condenser (13) of the distillation column. The tetrahydrofuran fraction and different types of phenylchlorosilane product fractions are collected in the receiving tank (14) of the distillation column in stages.

4. The continuous production process for phenylchlorosilane according to claim 3, characterized in that, In step S1, the chlorosilane is silicon tetrachloride or methyltrichlorosilane.

5. The continuous production process for phenylchlorosilane according to claim 3, characterized in that, In step S1, the reaction temperature of the Grignard reaction is 50–90°C, and the reaction pressure is 10–150 kPa.

6. The continuous production process for phenylchlorosilane according to claim 3, characterized in that, In step S2, the operating temperature of the vertical vacuum stirring dryer (6) is 150 to 250°C, and the system pressure is -95 to -99 kPa.

7. The continuous production process for phenylchlorosilane according to claim 3, characterized in that, In step S3, the temperature of the high-temperature nitrogen gas is 150 to 250°C, and the pressure during purging and drying is -95 to -99 kPa.

8. The continuous production process for phenylchlorosilane according to claim 3, characterized in that, In step S4, the bottom temperature of the phenylchlorosilane distillation column (11) is 50-220°C, and the reflux ratio is 1:1-10.

9. The continuous production process for phenylchlorosilane according to claim 3, characterized in that, In step S4, the collected phenylchlorosilane product fraction includes phenyltrichlorosilane, diphenyldichlorosilane, and triphenylmonochlorosilane.

10. The continuous production process for phenylchlorosilane according to claim 3, characterized in that, In step S1, the concentration of the phenyl magnesium chloride tetrahydrofuran solution is 10-35%; the molar ratio of the phenyl magnesium chloride to the chlorosilane is 1-3:1.

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