Method for preparing phenyl trichlorosilane by using trichlorosilane byproduct and phenyl trichlorosilane

Abstract

The invention belongs to the technical field of chlorosilane synthesis, and relates to a method for preparing phenyl trichlorosilane by using a trichlorosilane byproduct and the prepared phenyl trichlorosilane. The method comprises the following steps: firstly, taking metal silicon powder and hydrogen chloride gas as raw materials, reacting in a synthetic furnace under the action of a catalyst, and dedusting and cooling a reaction product to obtain a trichlorosilane crude product; rectifying the trichlorosilane crude product to obtain a high-boiling-point substance; and finally, under the irradiation of ultraviolet light, reacting the high-boiling-point substance serving as a raw material with chlorobenzene, and performing low-boiling-point removal and rectification to obtain the phenyl trichlorosilane. According to the method, the trichlorosilane by-product can be effectively utilized, and the problems of high cost, serious material waste and serious environmental pollution in the treatment process of the trichlorosilane by-product in the prior art are solved. The method is mild in condition and low in equipment requirement, and phenyl trichlorosilane can be prepared without a high-temperature thermal condensation reaction. According to the phenyl trichlorosilane obtained by the method, the yield is close to 80%, impurities are few, and the gas phase content reaches 99% or above.

Description

Technical Field

[0001] The invention belongs to the technical field of chlorosilane synthesis and relates to a method for preparing phenyltrichlorosilane by utilizing trichlorosilane byproduct and the prepared phenyltrichlorosilane. Background Art

[0002] Phenyltrichlorosilane is an important monomer for preparing phenylsilane coupling agents and silicone polymers, and has significant effects on improving the heat resistance, radiation resistance, and chemical stability of products. The main methods for industrial production of phenyltrichlorosilane at present include thermal condensation method, direct synthesis method and Grignard method. Among them, the thermal condensation method is to prepare trichlorosilane or methyldichlorosilane with chlorobenzene through a high temperature thermal condensation reaction at 600-700°C. The conversion rate of chlorosilane to phenyltrichlorosilane is 50-70%, which is relatively low. The direct synthesis method uses metals such as copper or silver powder as catalysts to catalyze the reaction of silicon powder and chlorobenzene at about 300°C. Although the temperature and equipment requirements required for the reaction are reduced, the reaction of chlorobenzene with silicon-copper and other promoters requires the addition of metals at 30-50% of the amount of silicon powder, which is costly. In addition, the diphenylsilane impurity generated at the same time has a boiling point close to that of the target product. The content of monophenylsilane generally cannot exceed 97%, which greatly limits its use. The Grignard method for preparing phenyltrichlorosilane has mild temperature conditions and will produce a large amount of polychlorinated biphenyls and biphenyls as by-products. At the same time, magnesium salts and magnesium have high solubility in solvents such as tetrahydrofuran, and the risk of recovering and using magnesium mixed in salts and solvents is high.

[0003] Trichlorosilane is the main raw material for the production of organosilicon and polysilicon. At present, trichlorosilane is mainly produced by the reaction of metallic silicon powder and hydrogen chloride. High boiling products are produced during production, including polychlorosilane and siloxane, such as Si2Cl6, HSi3Cl7, Si3Cl8, HSi4Cl9, Si4Cl 10 、Si5Cl 12 Among them, polychlorosilane can explode violently when impacted or heated, and has strong adhesion. It is easy to deposit on the inner wall of the pipeline and block the pipeline, which brings danger and difficulty to the cleaning of the pipeline. Especially for production lines that run for a long time, the explosion hazard is more prominent. How to safely and effectively deal with flammable and explosive polychlorosilane has always been a problem that troubles various trichlorosilane production companies. The most commonly used treatment method is to discharge it into an alkaline solution pool for neutralization and hydrolysis reaction. This simple treatment method has the problems of high cost, serious material waste and serious environmental pollution. Summary of the invention

[0004] Based on this, the object of the present invention is to provide a method for preparing phenyltrichlorosilane using trichlorosilane byproduct, which uses high boiling points produced in the production process of trichlorosilane as raw materials and reacts with chlorobenzene at a relatively low temperature to prepare phenyltrichlorosilane with high efficiency and low cost.

[0005] The invention also provides phenyltrichlorosilane prepared by the method.

[0006] To achieve the above object, the present invention adopts the following technical solutions: The present invention provides a method for preparing phenyltrichlorosilane by using trichlorosilane byproduct, comprising the following steps: S1, using metallic silicon powder and excess hydrogen chloride gas as raw materials, reacting under the action of a catalyst, and obtaining crude trichlorosilane after dust removal and cooling of the reaction product; S2, distilling the crude trichlorosilane to obtain high boiling products; S3, using the high boiling point as a raw material, reacting with chlorobenzene under ultraviolet light irradiation, and then removing the low boiling point and rectifying to obtain the product.

[0007] Further, the catalyst in S1 comprises 4 to 6 parts of cuprous chloride, 1 to 2 parts of vanadium pentoxide and 1 to 2 parts of zinc chloride, the components being measured in parts by weight; Furthermore, the mass ratio of the catalyst to the metal silicon powder in S1 is 0.01-0.03:1; Furthermore, the corresponding relationship between the metal silicon powder and the hydrogen chloride gas in S1 is: 1 kg of metal silicon powder passes through 2.8-3.2 m 3 Hydrogen chloride gas.

[0008] Furthermore, the reaction in S1 is carried out at a pressure of 45-50 KPa and a temperature of 340-400°C.

[0009] Furthermore, the product dust removal and cooling process in S1 includes: the product first passes through a cyclone dust collector and a bag dust collector in sequence to remove silicon ash and unreacted silicon powder impurities, then passes through a wet dust collector using the crude trichlorosilane product as a spray liquid for wet dust removal, and finally obtains the crude trichlorosilane by cooling.

[0010] Furthermore, the high boiling point substances include hexachlorodisilane and silicon tetrachloride, and also contain heptachlorotrisilane, octachlorotrisilane, etc.; wherein the content of the hexachlorodisilane is 80-88%, the content of the silicon tetrachloride is ≤5%, and the remainder is heptachlorotrisilane, octachlorotrisilane, etc.

[0011] Furthermore, the molar ratio of the hexachlorodisilane to the chlorobenzene is 1:1-2.

[0012] Furthermore, the wavelength range of the ultraviolet light in S3 is 200-380 nm, preferably 240-280 nm, the irradiation time is 2-4 h, and the reaction temperature is 100-120 °C.

[0013] Furthermore, the power of the ultraviolet light source in S3 is 10-30W, including a high-pressure mercury lamp, a low-pressure mercury lamp or an LED light source, preferably an LED light source, and the LED light source is preferably annular.

[0014] Furthermore, the distillation in S3 uses a 80~120 cm distillation column, a pressure of -0.08~-0.07 MPa, and a temperature of 120~123°C.

[0015] The present invention further provides phenyltrichlorosilane prepared by the method.

[0016] The beneficial effects of the present invention are: 1. The method for preparing phenyltrichlorosilane using trichlorosilane byproducts provided by the present invention can effectively utilize trichlorosilane byproducts, thereby solving the problems of high cost, serious material waste and serious environmental pollution in the treatment process of trichlorosilane byproducts in the prior art.

[0017] 2. By using a catalyst in the trichlorosilane synthesis system to increase the content of hexachlorodisilane in the high-boiling byproduct polychlorosilane, it is beneficial to enrich hexachlorodisilane and achieve high-efficiency and low-cost reaction of high-boiling products with chlorobenzene at a lower temperature to prepare phenyltrichlorosilane.

[0018] 3. The method for preparing phenyltrichlorosilane from trichlorosilane byproduct provided by the present invention uses ultraviolet light to irradiate hexachlorodisilane and chlorobenzene to react. Compared with the existing direct method for synthesizing phenyltrichlorosilane, the method has low equipment requirements, reduces the difficulty of the reaction, and does not produce polychlorinated biphenyls. Compared with the thermal condensation method for synthesizing phenyltrichlorosilane, the method has the advantages of low energy consumption, simple equipment, and low reaction conditions.

[0019] 4. The phenyltrichlorosilane provided by the present invention has a yield of nearly 80%, few impurities, and a gas phase content of more than 99%. DETAILED DESCRIPTION

[0020] The technical solution of the present invention is described clearly and completely below in conjunction with the embodiments. The embodiments mentioned are all implemented on the premise of the technical solution of the present invention, and detailed implementation processes are given, but it should be stated that the protection scope of the present invention is not limited to the following embodiments.

[0021] The method for preparing phenyltrichlorosilane using trichlorosilane byproducts adopted in the embodiment of the present invention comprises the following steps: S1, using metallic silicon powder and hydrogen chloride gas as raw materials, adding the raw materials into a trichlorosilane synthesis furnace, under the action of a catalyst, controlling the pressure and temperature of the synthesis furnace to start the reaction, after the reaction is completed, the product is dusted and cooled to obtain a crude trichlorosilane. This process uses a catalyst in a trichlorosilane synthesis system to catalyze the selective de-low condensation of chlorosilane at high temperature, that is, catalyze the intermolecular or intramolecular dehydrochlorination and dehydrogenation condensation of trichlorosilane and silicon tetrachloride, thereby increasing the yield of high-boiling hexachlorodisilane.

[0022] In this step, the pressure of the synthesis furnace is controlled to be 45~50Kpa and the temperature is 340~400℃. The catalyst includes 4~6 parts of cuprous chloride, 1~2 parts of vanadium pentoxide and 1~2 parts of zinc chloride, and the components are measured by weight. The mass ratio of the catalyst to the metal silicon powder is 0.01~0.03:1. After adding silicon powder into the synthesis furnace, dry hydrogen chloride gas is continuously introduced, and the hydrogen chloride is greatly excessive. The corresponding relationship between metal silicon powder and hydrogen chloride gas is 1Kg of silicon powder is passed through 2.8~3.2m 3 Hydrogen chloride gas.

[0023] The product in this step first passes through a cyclone dust collector and a bag dust collector to remove silicon ash and unreacted silicon powder impurities, then passes through a wet dust collector using the crude trichlorosilane product as a spray liquid for wet dust removal, and finally obtains the crude trichlorosilane through a water cooling and salt cooling device. The specific quality indicators of the crude trichlorosilane product selected in this step are: air 0.015%, hydrogen chloride 0.026%, dichlorodihydrosilane 0.327%, trichlorosilane 77.772%, silicon tetrachloride 20.623%, methyl trichloro 0.642%, hexachlorodisilane 0.427%, and octachlorotrisilane 0.168%. The specific quality indicators of the crude trichlorosilane product are not limited to this.

[0024] S2, the crude trichlorosilane is distilled to obtain high boiling products. The distillation process used in this step is to collect high-purity trichlorosilane and silicon tetrachloride by segmented distillation at 33~35℃ and 57~59℃. On the basis of step S1, the high boiling products obtained by this process mainly include hexachlorodisilane and silicon tetrachloride; the content of hexachlorodisilane is 80~88%, the content of silicon tetrachloride is ≤5%, and the remainder is heptachlorotrisilane, octachlorotrisilane, nonachlorotetrasilane and hydrolysis condensation high boiling products.

[0025] S3, using high boiling point as raw material, reacting with chlorobenzene under ultraviolet irradiation, and then removing low and rectifying to obtain. This step adopts ultraviolet irradiation, and in the present embodiment, a LED annular light source with a light source power of 10-30W is selected, and the wavelength range is 245-275nm, which can break the Si-Si bond in hexachlorodisilane to produce trichlorosilyl free radicals, and the free radicals can react with chlorobenzene under the low temperature condition of 110-115°C to obtain crude phenyltrichlorosilane, remove low by distillation, remove hydrogen chloride, dichlorodihydrosilane, trichlorosilane, silicon tetrachloride, chlorobenzene and hexachlorodisilane, etc., and then rectify with 80-120cm distillation column at -0.08--0.07Mpa, 120-123°C to obtain high-purity phenyltrichlorosilane.

[0026] Example 1 The method of preparing phenyltrichlorosilane by using trichlorosilane byproduct comprises the following steps: S1, add 1000Kg of metallic silicon powder and 18Kg of catalyst (containing 10Kg of cuprous chloride, 4Kg of vanadium pentoxide and 4Kg of zinc oxide) into the synthesis furnace, and continuously introduce 2860m 3 Hydrogen chloride gas reacts at a pressure of 45~46Kpa and a temperature of 360~370℃. The synthetic product passes through a cyclone dust collector and a bag dust collector to remove silica ash and unreacted silicon powder impurities. Then, it passes through a wet dust collector using the existing crude trichlorosilane product as a spray liquid for wet dust removal. Then, the crude trichlorosilane is obtained through water cooling and salt cooling devices, of which hexachlorodisilane accounts for 1.12%.

[0027] S2, the crude trichlorosilane is subjected to fractional distillation to collect high-purity trichlorosilane and silicon tetrachloride to obtain high boiling products, of which hexachlorodisilane accounts for 81.4% and silicon tetrachloride accounts for 4.43%.

[0028] S3, react 20Kg of high boiling point with 8.86Kg of chlorobenzene in a transparent reaction pipe under ultraviolet irradiation at 100-105°C for 3h, the ultraviolet light source is a ring-shaped LED light source with a power of 20W and a wavelength range of 275nm, and the gas phase is monitored to a chlorobenzene content of 0.46%. The material is transferred to a reactor, distilled to remove the low, and then distilled through an 80cm distillation column at -0.08--0.07Mpa and 120-123°C to obtain 10.04Kg of phenyltrichlorosilane with a gas phase content of 99.37%, with a yield of 78.4%.

[0029] Example 2 The method of preparing phenyltrichlorosilane by using trichlorosilane byproduct comprises the following steps: S1, add 1000Kg of metallic silicon powder and 26Kg of catalyst (containing 14.6Kg of cuprous chloride, 5.7 parts of vanadium pentoxide and 5.7 parts of zinc oxide) into the synthesis furnace, and pass 3000m 3Hydrogen chloride gas reacts at a pressure of 47~48Kpa and a temperature of 370~380℃. The synthetic product passes through a cyclone dust collector and a bag dust collector to remove silica ash and unreacted silicon powder impurities, and then passes through a wet dust collector using the existing crude trichlorosilane product as a spray liquid for wet dust removal. Then, the crude trichlorosilane is obtained through water cooling and salt cooling devices, of which hexachlorodisilane accounts for 1.23%.

[0030] S2, the crude trichlorosilane is subjected to fractional distillation to collect high-purity trichlorosilane and silicon tetrachloride to obtain high boiling products, of which hexachlorodisilane accounts for 83.5% and silicon tetrachloride accounts for 4.68%.

[0031] S3, 20Kg of high boiling products and 9.93Kg of chlorobenzene were reacted at 105-108℃ in a transparent reaction tube under ultraviolet irradiation for 3h. The ultraviolet light source was a ring-shaped LED light source with a power of 15W and a wavelength range of 245nm. The chlorobenzene content in the gas phase was monitored to be 0.43%. The material was transferred to a reactor, distilled to remove the low, and then distilled through a 120cm distillation column at ~0.08~-0.07Mpa and 120-123℃ to obtain 10.18Kg of phenyltrichlorosilane with a gas phase content of 99.56%, with a yield of 77.5%.

[0032] Example 3 The method of preparing phenyltrichlorosilane by using trichlorosilane byproduct comprises the following steps: S1, add 1000Kg of metal silicon powder, 23Kg of catalyst (containing 12.8Kg of cuprous chloride, 5.1Kg of vanadium pentoxide and 5.1Kg of zinc oxide) into the synthesis furnace, and pass 2900m 3 Hydrogen chloride gas reacts at a pressure of 49~50Kpa and a temperature of 380~390℃. The synthetic product passes through a cyclone dust collector and a bag dust collector to remove silica ash and unreacted silicon powder impurities. Then, it passes through a wet dust collector using the existing crude trichlorosilane product as a spray liquid for wet dust removal. Then, the crude trichlorosilane is obtained through water cooling and salt cooling devices, of which hexachlorodisilane accounts for 1.33%.

[0033] S2, the crude trichlorosilane is subjected to fractional distillation to collect high-purity trichlorosilane and silicon tetrachloride to obtain high boiling products, of which hexachlorodisilane accounts for 86.7% and silicon tetrachloride accounts for 3.82%.

[0034] S3, 20Kg of high boiling products and 12.63Kg of chlorobenzene were reacted at 110~115℃ in a transparent reaction pipe under ultraviolet irradiation for 2.5h. The ultraviolet light source was a ring-shaped LED light source with a power of 20W and a wavelength range of 275nm. The chlorobenzene content in the gas phase was monitored to be 0.52%. The material was transferred to a reactor, distilled to remove the low, and then distilled through a 100cm distillation column at -0.08~-0.07Mpa and 120~123℃ to obtain 10.8Kg of phenyltrichlorosilane with a gas phase content of 99.42%, with a yield of 79.1%.

[0035] Example 4 The method of preparing phenyltrichlorosilane by using trichlorosilane byproduct comprises the following steps: S1, add 1000Kg of metallic silicon powder, 30Kg of catalyst (containing 16.8Kg of cuprous chloride, 6.6Kg of vanadium pentoxide and 6.6Kg of zinc oxide) into the synthesis furnace, and pass 2800m 3 Hydrogen chloride gas reacts at a pressure of 46~47Kpa and a temperature of 350~360℃. The synthetic product passes through a cyclone dust collector and a bag dust collector to remove silica ash and unreacted silicon powder impurities. Then, it passes through a wet dust collector using the existing crude trichlorosilane product as a spray liquid for wet dust removal. Then, the crude trichlorosilane is obtained through water cooling and salt cooling devices, of which hexachlorodisilane accounts for 1.14%.

[0036] S2, the crude trichlorosilane is subjected to fractional distillation to collect high-purity trichlorosilane and silicon tetrachloride to obtain high boiling products, of which hexachlorodisilane accounts for 87.4% and silicon tetrachloride accounts for 3.29%.

[0037] S3, 20Kg of high boiling point and 11.85Kg of chlorobenzene were reacted in a transparent reaction tube under ultraviolet irradiation at 110~115℃ for 3.5h. The ultraviolet light source was a ring-shaped LED light source with a power of 20W and a wavelength range of 245nm; the chlorobenzene content in the gas phase was monitored to be 0.37%. The material was transferred to a reactor, distilled to remove the low, and then distilled through a 100cm distillation column at -0.08~-0.07Mpa and 120~123℃ to obtain 10.95Kg of phenyltrichlorosilane with a gas phase content of 99.47%, with a yield of 79.6%.

[0038] Example 5 The method of preparing phenyltrichlorosilane by using trichlorosilane byproduct comprises the following steps: S1, add 1000Kg metal silicon powder, 11Kg catalyst (containing 6.2Kg cuprous chloride, 2.4Kg vanadium pentoxide and 2.4Kg zinc oxide) into the synthesis furnace, and pass 3200m 3Hydrogen chloride gas reacts at a pressure of 47~48Kpa and a temperature of 350~360℃. The synthetic product passes through a cyclone dust collector and a bag dust collector to remove silica ash and unreacted silicon powder impurities. Then, it passes through a wet dust collector using the existing crude trichlorosilane product as a spray liquid for wet dust removal. Then, the crude trichlorosilane is obtained through water cooling and salt cooling devices, of which hexachlorodisilane accounts for 1.07%.

[0039] S2, the crude trichlorosilane is subjected to fractional distillation to collect high-purity trichlorosilane and silicon tetrachloride to obtain high boiling products, of which hexachlorodisilane accounts for 82.4% and silicon tetrachloride accounts for 4.16%.

[0040] S3, 20Kg of high boiling point and 13.8Kg of chlorobenzene were reacted at 100~105℃ in a transparent reaction tube under ultraviolet irradiation for 3h. The ultraviolet light source was a ring-shaped LED light source with a power of 25W and a wavelength range of 275nm; the chlorobenzene content in the gas phase was monitored to be 0.52%. The material was transferred to a reactor, distilled to remove the low, and then distilled through a 100cm distillation column at -0.08~-0.07Mpa and 120~123℃ to obtain 9.83Kg of phenyltrichlorosilane with a gas phase content of 99.31%, with a yield of 75.8%.

[0041] Comparative Example 1 Preparation of phenyltrichlorosilane comprises the following steps: S1, add 1000Kg of metallic silicon powder into the synthesis furnace, and pass 3000m 3 Hydrogen chloride gas reacts at a pressure of 47-48Kpa and a temperature of 390-400℃. The synthetic product is passed through a cyclone dust collector and a bag dust collector to remove silicon ash and unreacted silicon powder impurities. Then, the product is passed through a wet dust collector using the existing crude trichlorosilane product as a spray liquid for wet dust removal. The crude trichlorosilane is then obtained through water cooling and salt cooling devices, of which hexachlorodisilane accounts for 0.341%; S2, the crude trichlorosilane is distilled and segmented to collect high-purity trichlorosilane and silicon tetrachloride to obtain high-boiling products, of which hexachlorodisilane accounts for 52.3%.

[0042] S3, react 20 kg of high boiling point substance with 8.3 kg of chlorobenzene in a reactor at 45-46 KPa pressure and 300-310 °C temperature for 4 hours. The chlorobenzene content was 0.26% when monitored in the gas phase, and no phenyltrichlorosilane was generated.

[0043] Comparative Example 2 Preparation of phenyltrichlorosilane comprises the following steps: S1, add 1000Kg of metallic silicon powder into the synthesis furnace, and pass 2900m 3Hydrogen chloride gas reacts at a pressure of 49~50Kpa and a temperature of 380~390℃. The synthetic product passes through a cyclone dust collector and a bag dust collector to remove silica ash and unreacted silicon powder impurities. Then, it passes through a wet dust collector using the existing crude trichlorosilane product as a spray liquid for wet dust removal. Then, the crude trichlorosilane is obtained through water cooling and salt cooling devices, of which hexachlorodisilane accounts for 0.318%.

[0044] S2, the crude trichlorosilane is subjected to distillation to collect high-purity trichlorosilane and silicon tetrachloride to obtain high boiling points. After the crude product is distilled, the high boiling points obtained include hexachlorodisilane accounting for 64.4% and silicon tetrachloride accounting for 4.82%.

[0045] S3, 20Kg of high boiling point and 8.73Kg of chlorobenzene were reacted at 110~115℃ in a transparent reaction tube under ultraviolet irradiation for 3.5h. The ultraviolet light source was a ring-shaped LED light source with a power of 20W and a wavelength range of 245nm; the chlorobenzene content in the gas phase was monitored to be 0.42%. The material was transferred to a reactor, distilled to remove the low, and then distilled through an 80cm distillation column at -0.08~-0.07Mpa and 120~123℃ to obtain 5.9Kg of phenyltrichlorosilane with a gas phase content of 99.67%, with a yield of 58.2%.

[0046] Comparative Example 3 Preparation of phenyltrichlorosilane comprises the following steps: S1, add 1000Kg metal silicon powder, 22Kg catalyst (containing 12.4Kg cuprous chloride, 4.8Kg vanadium pentoxide and 4.8Kg zinc oxide) into the synthesis furnace, and pass 3100m 3 Hydrogen chloride gas reacts at a pressure of 49~50Kpa and a temperature of 360~370℃. The synthetic product passes through a cyclone dust collector and a bag dust collector to remove silica ash and unreacted silicon powder impurities. Then, it passes through a wet dust collector using the existing crude trichlorosilane product as a spray liquid for wet dust removal. Then, the crude trichlorosilane is obtained through water cooling and salt cooling devices, of which hexachlorodisilane accounts for 1.27%.

[0047] S2, the crude trichlorosilane is subjected to fractional distillation to collect high-purity trichlorosilane and silicon tetrachloride to obtain high boiling products, of which hexachlorodisilane accounts for 84.5% and silicon tetrachloride accounts for 5.82%.

[0048] S3, 20Kg of high boiling point and 12.73Kg of chlorobenzene were reacted in a transparent reaction tube under ultraviolet irradiation at 115~120℃ for 3.5h. The ultraviolet light source was a ring-shaped LED light source with a power of 30W and a wavelength range of 310nm; the chlorobenzene content in the gas phase was monitored to be 0.26%. The material was transferred to the reactor, distilled to remove the low, and then distilled through a 120cm distillation column at -0.08~-0.07Mpa and 120~123℃ to obtain 8.3Kg of phenyltrichlorosilane with a gas phase content of 99.51%, with a yield of 62.4%.

[0049] As can be seen from Examples 1-5, the method for preparing phenyltrichlorosilane using trichlorosilane byproduct provided by the present invention uses a mixture of cuprous chloride, vanadium pentoxide and zinc chloride as a catalyst in a trichlorosilane synthesis system, and catalyzes the selective de-low condensation of chlorosilane at a high temperature of 340-400°C, that is, catalyzes the intermolecular or intramolecular dehydrochlorination and dehydrogenation condensation of trichlorosilane and silicon tetrachloride, thereby increasing the output rate of high-boiling hexachlorodisilane, and the output rate reaches 80-88%. The higher the purity of hexachlorodisilane, the less the content of silicon tetrachloride, and the higher the yield of phenyltrichlorosilane prepared by free radical reaction under irradiation at a suitable ultraviolet wavelength; the results show that the yield of phenyltrichlorosilane in the present invention is nearly 80%, and the impurities are few, and the gas phase content is more than 99%.

[0050] It can be seen from Comparative Examples 1-3 that in Comparative Examples 1 and 2, without adding a catalyst, increasing the temperature and the ventilation volume of hydrogen chloride cannot increase the proportion of hexachlorodisilane in the high boiling products. 10 The ratio of polychlorosilane and hydrolysis to produce polychlorosiloxane is high. In Comparative Example 1, hexachlorodisilane accounts for only 52.3% of the high-boiling substances. When reacting with chlorobenzene, no phenyltrichlorosilane is generated under the condition of no ultraviolet irradiation. In Comparative Example 2, hexachlorodisilane accounts for only 64.4% of the high-boiling substances. When reacting with chlorobenzene, no ultraviolet irradiation, the final yield of phenyltrichlorosilane is only 58.2%. In Comparative Example 3, due to the silicon tetrachloride remaining 5.82%, it exceeds the optimal range, and the wavelength of ultraviolet light is 310nm, which makes the free radical effect poor, and ultimately leads to a decrease in the yield of phenyltrichlorosilane, with a yield of only 62.4%.

[0051] In summary, the present invention improves the content of hexachlorodisilane in the high-boiling products of polychlorosilane, a byproduct, by using a catalyst in a trichlorosilane synthesis system, which is beneficial to the enrichment of hexachlorodisilane, and realizes the process of preparing phenyltrichlorosilane by high-efficiency and low-cost reaction of high-boiling products with chlorobenzene at a relatively low temperature. Compared with the existing direct method for synthesizing phenyltrichlorosilane, the requirements for the reaction device are greatly simplified, the equipment requirements are low, the reaction difficulty is reduced, and polychlorinated biphenyls are not produced. Compared with the thermal condensation method for synthesizing phenyltrichlorosilane, it has the advantages of low energy consumption, simple equipment, and low reaction conditions. The phenyltrichlorosilane prepared by the method for preparing phenyltrichlorosilane using trichlorosilane byproduct provided by the present invention has a yield of nearly 80%, and few impurities, and a gas phase content of more than 99%.

[0052] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing phenyltrichlorosilane using trichlorosilane byproduct, characterized in that: The steps include: S1, using metallic silicon powder and excess hydrogen chloride gas as raw materials, reacting under the action of a catalyst, and obtaining crude trichlorosilane after dust removal and cooling of the reaction product; S2, distilling the crude trichlorosilane to obtain high boiling products; S3, using the high boiling point as a raw material, reacting with chlorobenzene under ultraviolet irradiation, and then removing the low boiling point and rectifying to obtain the product.

2. The method according to claim 1, characterized in that The catalyst in S1 comprises 4 to 6 parts of cuprous chloride, 1 to 2 parts of vanadium pentoxide and 1 to 2 parts of zinc chloride, the components being measured in parts by weight.

3. The method according to claim 1, characterized in that The mass ratio of the catalyst to the metal silicon powder in S1 is 0.01-0.03:

1.

4. The method according to claim 1, characterized in that The corresponding relationship between the metal silicon powder and the hydrogen chloride gas in S1 is: 2.8-3.2m3 of hydrogen chloride gas is introduced into the gas per 1kg of metal silicon powder. 3 Hydrogen chloride gas.

5. The method according to claim 1, characterized in that The reaction in S1 is carried out under the conditions of a pressure of 45-50 KPa and a temperature of 340-400°C.

6. The method according to claim 1, characterized in that The high boiling point substance contains hexachlorodisilane and silicon tetrachloride, and the molar ratio of the hexachlorodisilane to the chlorobenzene is 1:1-2.

7. The method according to claim 1, characterized in that The wavelength range of the ultraviolet light in S3 is 200-380 nm, the irradiation time is 2-4 h, and the reaction temperature is 100-120 °C.

8. The method according to claim 1, characterized in that The ultraviolet light source power described in S3 is 10~30W, including a high-pressure mercury lamp, a low-pressure mercury lamp or an LED light source.

9. The method according to claim 1, characterized in that The distillation in S3 uses a 80~120cm distillation column, a pressure of -0.08~-0.07Mpa, and a temperature of 120~123°C.

10. A phenyltrichlorosilane, characterized in that It is prepared by the method according to any one of claims 1 to 9.