Method for catalytic synthesis of phenyl chlorosilane by using ZnCo-ZIF / CeO2 catalyst and the catalyst

Abstract

The application belongs to the field of chemical industry, and specifically provides a method for catalytically synthesizing phenyl chlorosilane by using ZnCo-ZIF / CeO2 and a catalyst used in the method, which comprises the following steps: synthesizing nano CeO2 by using Ce(NO3)3.6H2O and urea through a hydrothermal method, and preparing ZnCo-ZIF / CeO2 by using Co(NO3)2.6H2O, Zn(NO3)2.6H2O, CeO2 and 2-methyl imidazole. The application also simultaneously provides a method for preparing phenyl chlorosilane by using the ZnCo-ZIF / CeO2 catalyst: adding the catalyst into a fixed bed reaction furnace, taking chlorosilane and chlorobenzene as raw materials, and reorganizing and synthesizing phenyl chlorosilane in the fixed bed reaction furnace. The method has the characteristics of low reaction temperature, good selectivity and the like.

Description

Technical Field

[0001] This invention belongs to the field of chemical engineering and relates to the preparation of catalytic materials and the preparation of phenylchlorosilanes, specifically to the application of a ZnCo-ZIF / CeO2 catalyst in the preparation of phenylchlorosilanes. Background Technology

[0002] With the continuous development of the chemical industry, silane compounds have gradually become one of the important raw materials in the building materials, electronics, automotive, and cosmetics industries. Phenylsilanes and diphenylsilanes, as silane compounds, are important raw materials for synthesizing various coupling agents or crosslinking agents, and are particularly suitable for manufacturing high-performance silicone rubbers, silicone oils, and silicone resins. Introducing phenyl units into the aforementioned silicone polymer molecules can effectively improve the heat resistance, chemical stability, radiation resistance, and refractive index of the products.

[0003] Commonly used phenylchlorosilanes include phenyltrichlorosilane, methylphenyldichlorosilane, and diphenyldichlorosilane. Currently, the main methods for preparing phenylsilanes and diphenylsilanes include liquid-phase condensation, Grignard method, pyrolysis method, acid binding method, disproportionation method, thermal condensation method, sodium condensation method, and direct synthesis method.

[0004] The liquid-phase condensation method involves irradiating the reactants with light of a specific wavelength (such as ultraviolet light), which then triggers a photo-initiated free radical reaction to generate phenylchlorosilane. The Jilin Chemical Company Research Institute achieved a yield exceeding 54% and a selectivity of 62% in the synthesis of methylphenyldichlorosilane using methyldichlorosilane, benzene, and chlorine as raw materials (Research on the Photosynthesis of Methylphenyldichlorosilane [J]. Synthetic Rubber Industry, 1980(3):188-191). Xiao Lin et al. synthesized methylphenyldiethoxysilane using magnesium, methyltriethoxysilane, and chlorobenzene as raw materials, with a yield of 60.1% (Synthesis process and optimization of methylphenyldiethoxysilane [J]. Journal of Nanchang University, 2009, 31(3):227-229.). Patent CN101195633A discloses the cracking reaction of a mixture of trimethyltrichlorodisilane and dimethyltetrachlorodisilane with halobenzene under the catalysis of Group VIII and its complexes, with a yield of up to 80% for the product methylphenyldichlorosilane, but the catalyst is expensive and difficult to recover. Patent CN1807432A discloses the use of alkylimidazolium as an acid-binding agent to promote the reaction of methyldichlorosilane with chlorobenzene, followed by cooling and precipitation after the reaction to separate the alkylimidazolium hydrochloride from the methylphenyldichlorosilane, with a yield of up to 84.2%, but the reaction time of this method is relatively long and the product composition is complex.

[0005] Patent CN101628917A describes the preparation of methylphenyldichlorosilane in a self-made reactor under conditions of 0.2–0.8 MPa and 350–600 °C using chlorobenzene and methyldichlorosilane as raw materials and chloroform, dichloromethane, or carbon tetrachloride as catalysts. This method has drawbacks, such as low yield (reaching a maximum of 52.7%) due to the high temperature and pressure conditions.

[0006] The study of the fixed-bed synthesis of phenylsilanes using the gas-phase condensation method will be of great significance for the research and development of large-scale production processes for phenylchlorosilanes if a high-performance catalyst can be found to lower the reaction energy barrier and achieve efficient and green synthesis. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a method for the synthesis of phenylchlorosilanes by ZnCo-ZIF / CeO2 catalysis and the catalyst used.

[0008] To address the aforementioned technical problems, this invention provides a method for preparing a nano-CeO2-supported ZnCo-ZIF bimetallic catalyst, comprising the following steps:

[0009] 1.1) Preparation of nano CeO2 (CeO2 synthesized by hydrothermal method): prepared using Ce(NO3)3·6H2O and urea;

[0010] 1.2) Preparation of ZnCo-ZIF / CeO2: ZnCo-ZIF / CeO2 was prepared using Co(NO3)2·6H2O, Zn(NO3)2·6H2O, CeO2, and 2-methylimidazole.

[0011] An improvement to the preparation method of the nano-CeO2-supported ZnCo-ZIF bimetallic catalyst of the present invention:

[0012] 1.1) Preparation of nano-CeO2:

[0013] Ce(NO3)3·6H2O and urea were added to deionized water and stirred to form a homogeneous mixture with a molar ratio of Ce(NO3)3·6H2O:urea = 1:(1.5±0.1).

[0014] The homogeneous mixture was then transferred to a hydrothermal reactor and hydrothermally treated at 120–160℃ (preferably 150–160℃) for 5 ± 0.5 h. The mixture was then centrifuged (at 10000 ± 1000 rpm for 10 ± 2 min), and the resulting solid was washed, dried, and then calcined at 600 ± 50℃ for 5 ± 0.5 h to obtain nano CeO2 (pale yellow nano CeO2).

[0015] Note: Calcination can be carried out in a muffle furnace;

[0016] 1.2) Preparation of ZnCo-ZIF / CeO2

[0017] The molar ratio n(Co(NO3)2·6H2O):n(Zn(NO3)2·6H2O):n(CeO2):n(2-methylimidazole) is set to 1~3:2~5:10:10;

[0018] CeO2 powder was dispersed in anhydrous methanol, and then Zn(NO3)2·6H2O and Co(NO3)2·6H2O were added and ultrasonically dispersed. This dispersion was denoted as dispersion A.

[0019] Dissolve 2-methylimidazole in anhydrous methanol, and denote this solution as solution B;

[0020] Then, solution B was added to dispersion A and stirring was continued for 6–12 h. After that, the mixture was centrifuged (10000±1000 rpm for 10±2 min). The solid obtained by centrifugation was washed and dried to obtain the ZnCo-ZIF / CeO2 catalyst.

[0021] As a further improvement to the preparation method of the nano-CeO2-supported ZnCo-ZIF bimetallic catalyst of the present invention, in step 1.1):

[0022] For every 10 mmol of Ce(NO3)3·6H2O, use 100±20 ml of deionized water;

[0023] Stirring at room temperature for 1.5–2.5 hours forms a homogeneous mixture;

[0024] The solid obtained by centrifugation was washed with ethanol and pure water, respectively, and then vacuum dried at 70±10℃ for 10-14 h, followed by drying at 4-6℃·min. -1 The heating rate was increased to 600±50℃ and calcined for 5±0.5h.

[0025] As a further improvement to the preparation method of the nano-CeO2-supported ZnCo-ZIF bimetallic catalyst of the present invention, in step 1.2):

[0026] Use 20±5 ml of anhydrous methanol for every 6.0 mmol CeO2;

[0027] For every 6.0 mmol of 2-methylimidazole, use 20 ± 5 ml of anhydrous methanol;

[0028] The solid obtained by centrifugation was washed with ethanol and pure water, respectively, and then dried under vacuum at 70±10℃ for 10-14 h to obtain the ZnCo-ZIF / CeO2 catalyst.

[0029] As a further improvement to the preparation method of the nano-CeO2-supported ZnCo-ZIF bimetallic catalyst of the present invention,

[0030] In step 1.1), the hydrothermal treatment temperature is 160℃;

[0031] In step 1.2), n(Co(NO3)2·6H2O):n(Zn(NO3)2·6H2O):n(CeO2):n(2-methylimidazole) = 1:2~5:10:10; stirring time 8~12h (more preferably 10h).

[0032] This invention also provides a method for preparing phenylchlorosilanes using the ZnCo-ZIF / CeO2 catalyst obtained by any of the above methods:

[0033] A catalyst (ZnCo-ZIF / CeO2 catalyst) is added to a fixed-bed reactor, and then an inert gas (e.g., nitrogen) is introduced to purge the reactor.

[0034] Then, the chlorinated silanes and chlorobenzene used as raw materials are preheated and vaporized to obtain vaporized products, with a feed ratio of V. 含氯硅烷 :V 氯苯 =1:1.2~1.7; then the vaporized material is passed into a fixed-bed reactor packed with catalyst, with a volume hourly space velocity of 300~500 h⁻¹. -1 (Preferred 350-425h) -1 The reaction pressure is 0.1–1.0 MPa (0.4–0.7 MPa), and the reaction temperature is 200°C–350°C (preferably 250–300°C).

[0035] Volumetric space velocity = Volumetric flow rate after feed gasification (L / h) / Catalyst loading volume (L);

[0036] The reaction product is condensed (to below 25°C) after exiting the fixed-bed reactor, and then undergoes gas-liquid separation to obtain phenylchlorosilane as the product. Specifically, the condensate enters a gas-liquid separator to separate the product from hydrogen chloride gas.

[0037] As an improvement to the method for preparing phenylchlorosilane of the present invention:

[0038] The chlorosilane is any of the following: trichlorosilane, phenylchlorosilane, phenyldichlorosilane, methyldichlorosilane, dimethyldichlorosilane, triethylchlorosilane, ethyltrichlorosilane, diethyldichlorosilane, methylvinylchlorosilane, vinyltrichlorosilane.

[0039] As an improvement to the method for preparing phenylchlorosilane of the present invention: the liquid feed rate is 0.003 to 0.005 L / h.

[0040] The fixed-bed reactor used in this invention has a furnace length of 800 mm, an outer diameter of 30 mm, and an inner diameter of 25 mm. A catalyst is added to the fixed-bed reactor, with a catalyst loading amount of 15-20 g.

[0041] The reaction formula is as follows:

[0042]

[0043] This invention first prepared a CeO2-supported ZnCo-ZIF alloy catalyst, which was then recombinated into phenylchlorosilane (phenylsilane or diphenylsilane, etc.) in a fixed-bed reactor using chlorosilane and chlorobenzene as raw materials. This process has the characteristics of low reaction temperature and good selectivity.

[0044] This invention successfully prepared a ZnCo-ZIF / CeO2 bimetallic catalyst by loading ZnCo-ZIF onto the surface of nano-CeO2. This catalyst is used to catalyze the recombination of chlorosilanes and chlorobenzene into phenylsilanes or diphenylsilanes. ZnCo-ZIF / CeO2 possesses a high specific surface area, pore volume, and abundant acid-base sites, and exhibits a high adsorption capacity for chlorobenzene, which is beneficial for the adsorption of reactants by the catalyst. Furthermore, a strong interaction exists between the nano-CeO2 support and the metal component, which helps stabilize the metal particles and prevents sintering or agglomeration during the reaction. The method for preparing phenylchlorosilanes according to this invention is suitable for continuous production, significantly increasing production capacity. In addition, this invention lowers the reaction temperature for the recombination of chlorosilanes and chlorobenzene into phenylsilanes or diphenylsilanes, and the prepared catalyst has a long lifetime, high reaction selectivity, high feed conversion rate, and reduced production costs. Attached Figure Description

[0045] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0046] Figure 1 This is a schematic diagram of a fixed-bed continuous production unit. Detailed Implementation

[0047] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto:

[0048] Example 1: A fixed-bed continuous production apparatus for synthesizing phenylchlorosilanes, such as... Figure 1 As shown;

[0049] It includes an N2 cylinder 1 for supplying N2, a raw material tank I 2 for supplying chlorosilane, a raw material tank II 3 for supplying chlorobenzene, a preheating vaporization chamber 19, a fixed-bed reactor 22, a condenser 24, a low-temperature circulation tank 25, a gas-liquid separator 29, and a washing tank 34.

[0050] Cylinder 1 is connected to the inlet of mixer 17 in sequence through ball valve III4, rotor flow meter I5, and check valve III6;

[0051] Raw material tank I2 is connected to the inlet of mixer 17 in sequence through ball valve I7, metering pump I8, and check valve I11; metering pump I8 is equipped with flow display controller I10; pressure gauge I9 is ​​installed between metering pump I8 and check valve I11;

[0052] Raw material tank II3 is connected to the inlet of mixer 17 in sequence through ball valve II12, metering pump II13, and check valve II16. Metering pump II13 is equipped with flow display controller II15, and pressure gauge II14 is installed between metering pump II13 and check valve II16.

[0053] That is, metering pump I8 and metering pump II13 are each equipped with a flow display controller after the pump.

[0054] The outlet of mixer 17 is connected to the inlet of preheating vaporization chamber 19. The outlet of preheating vaporization chamber 19 is connected to the top of fixed-bed reactor 22 via a pipe equipped with a heat tracing cable 20. Preheating vaporization chamber 19 is equipped with a temperature controller 18. The fixed-bed reactor 22 is equipped with a thermocouple 23 for temperature measurement; a pressure gauge 21 is installed at the top of fixed-bed reactor 22.

[0055] The condenser 24 is equipped with a low-temperature circulation tank 25, and a flow regulating valve 26 is provided on the pipeline connecting the low-temperature circulation tank 25 and the condenser 24.

[0056] The bottom outlet of the fixed-bed reactor 22 is connected to the inlet of the condenser 24. The outlet of the condenser 24 is connected to the inlet of the gas-liquid separator 29 through a pipeline equipped with a ball valve 28. The bottom outlet (liquid phase outlet) of the gas-liquid separator 29 is equipped with a ball valve 30 and a shut-off valve 31. The top outlet (gas phase outlet) of the gas-liquid separator 29 is divided into two paths. One path is connected to the gas receiving bag after passing through the shut-off valve 32, and the other path is connected to the inlet of the water scrubbing tank 34 through the shut-off valve 33 to absorb hydrogen chloride in the tail gas. The outlet of the scrubbing tank 34 is the environment (VENT).

[0057] The fixed-bed reactor 22 is a 316L stainless steel tube with a furnace length of 800mm, an outer diameter of 30mm, and an inner diameter of 25mm. The constant temperature zone is about 50mm long.

[0058] Example 1: A method for preparing phenyltrichlorosilane using trichlorosilane and chlorobenzene, comprising the following steps:

[0059] 1. Preparation of ZnCo-ZIF / CeO2 catalyst:

[0060] 1.1) Preparation of nano CeO2

[0061] CeO2 was synthesized via a hydrothermal method. Specifically, 4.34 g (10.0 mmol) of Ce(NO3)3·6H2O and 0.90 g (15.0 mmol) of urea were dissolved in 100 ml of deionized water and stirred at room temperature for 2 h to form a homogeneous mixture. The homogeneous mixture was then transferred to a hydrothermal reactor and hydrothermally treated at 160 °C for 5 h. Following this, the mixture was centrifuged at 10,000 rpm for 10 min. The resulting solid was washed three times with ethanol and pure water to remove residual raw materials. The solid was then vacuum dried overnight (approximately 12 h) at 70 °C to obtain a white powder. The powder was then further dried at 4–6 °C / min. -1 The temperature was increased to 600℃ and calcined for 5 hours to obtain a light yellow CeO2 powder.

[0062] The pale yellow CeO2 powder was measured by specific surface area analysis, and the average particle size was approximately 10 nm; therefore, it belongs to nano CeO2.

[0063] 1.2) Preparation of ZnCo-ZIF / CeO2

[0064] Take 1.03 g (6.0 mmol) of CeO2 powder and disperse it in 20 ml of anhydrous methanol. Then add 0.36 g (1.2 mmol) of Zn(NO3)2·6H2O and 0.17 g (0.6 mmol) of Co(NO3)2·6H2O, and disperse it by sonication. This is called dispersion A.

[0065] Separately, 0.58 g (6.0 mmol) of 2-methylimidazole was dissolved in 20 ml of anhydrous methanol, and this solution was designated as solution B.

[0066] Then, solution B was added to solution A and stirred for 6 hours. The mixture was then centrifuged at 10,000 rpm for 10 minutes. Finally, the collected solid was washed three times with ethanol and pure water, and then vacuum dried overnight at 70°C to obtain the ZnCo-ZIF / CeO2 catalyst.

[0067] That is, in this Example 1, n(Co(NO3)2·6H2O):n(Zn(NO3)2·6H2O):n(CeO2):n(2-methylimidazole)=1:2:10:10.

[0068] 2. Catalyst loading

[0069] Take 20g of the catalyst obtained in step 1.2) and place it in the constant temperature zone of the fixed bed reactor 22. Open ball valve III4 and introduce N2 supplied by N2 cylinder 1 at a flow rate of 0.005L / h. Figure 1 Inside the device, impurities are purged; nitrogen mixed with air is finally discharged from the outlet of the washing tank 34, and the nitrogen purging time is 10 minutes.

[0070] Then close ball valve Ⅲ4 and proceed to step 3 below.

[0071] 3. Feeding and Discharging

[0072] The reaction pressure inside the fixed-bed reactor 22 is controlled to be stable at 0.4 MPa. The temperature of the preheating vaporization chamber 19 is maintained at 240°C, and the temperature of the fixed-bed reactor 22 is maintained at 250°C, by adjusting the heating power of the reactor jacket. Ball valves I7 and II12, as well as metering pumps I8 and II13, are opened. Chlorobenzene is then introduced at a rate of 0.005 L / h, and trichlorosilane is introduced at a rate of 0.003 L / h. The raw materials composed of chlorobenzene and trichlorosilane are mixed uniformly in mixer 17 and then enter the preheating vaporization chamber 19 for vaporization. The reaction then proceeds in the fixed-bed reactor 22 under the action of a catalyst. The reaction pressure is 0.4 MPa, the reaction temperature is 250°C, and the feed volume hourly space velocity is 350 h⁻¹. -1 .

[0073] Note: Feed volumetric space velocity = Volumetric flow rate after feed gasification (L / h) / Catalyst loading volume (L)

[0074] The reaction formula is

[0075] The reaction products are finally condensed in condenser 24 and then enter gas-liquid separator 29. At this time, phenyltrichlorosilane in the reaction products is condensed into liquid, while hydrogen chloride in the reaction products remains gaseous. Therefore, phenyltrichlorosilane is discharged from the liquid phase outlet of gas-liquid separator 29, while hydrogen chloride is discharged from the gas phase outlet of gas-liquid separator 29 and then absorbed in water washing tank 34.

[0076] The liquid phase outlet of the gas-liquid separator 29 is connected to an online gas phase detection and evaluation device. The product composition is detected every 5 minutes. After 30 minutes of reaction, the reaction is stable. After stabilization, the amount of trichlorosilane used is 0.06710 g every 1 minute of reaction, and 0.07367 g of the target product phenyltrichlorosilane is obtained, so the yield is 70.3%.

[0077] Yield = n 苯基三氯硅烷 / n 三氯氢硅 ×100%.

[0078] Example 2-1: Compared with Example 1, the following changes are made: the hydrothermal temperature in step 1.1) of the preparation of nano CeO2 is changed from 160℃ to 120℃, and the rest is the same as in Example 1.

[0079] The pale yellow CeO2 powder has an average particle size of approximately 3 nm; the yield of stabilized phenyltrichlorosilane is 64.7%.

[0080] Example 2-2: Compared with Example 1, the following changes were made: the hydrothermal temperature in step 1.1) of the preparation of nano CeO2 was changed from 160℃ to 140℃, and the rest was the same as in Example 1.

[0081] The pale yellow CeO2 powder has an average particle size of approximately 5 nm; the yield of stabilized phenyltrichlorosilane is 67.2%.

[0082] Example 3-1: Compared to Example 1, the following changes are made:

[0083] Change “n(Co(NO3)2·6H2O):n(Zn(NO3)2·6H2O):n(CeO2):n(2-methylimidazole)” in step 1) from 1:2:10:10 to 1:3:10:10;

[0084] That is, the amount of Co(NO3)2·6H2O used is 0.6 mmol, the amount of Zn(NO3)2·6H2O used is 1.8 mmol, the amount of CeO2 used is 6.0 mmol, and the amount of 2-methylimidazole used is 6.0 mmol.

[0085] The rest is the same as in Example 1.

[0086] The yield of stabilized phenyltrichlorosilane was 75.4%.

[0087] Example 3-2: Compared to Example 1, the following changes are made:

[0088] Change “n(Co(NO3)2·6H2O):n(Zn(NO3)2·6H2O):n(CeO2):n(2-methylimidazole)” in step 1) from 1:2:10:10 to 1:5:10:10;

[0089] That is, the amount of Co(NO3)2·6H2O used is 0.6 mmol, the amount of Zn(NO3)2·6H2O used is 3.0 mmol, the amount of CeO2 used is 6.0 mmol, and the amount of 2-methylimidazole used is 6.0 mmol.

[0090] The rest is the same as in Example 1.

[0091] The yield of stabilized phenyltrichlorosilane was 80.6%.

[0092] Example 3-3: Compared to Example 1, the following changes are made:

[0093] Change “n(Co(NO3)2·6H2O):n(Zn(NO3)2·6H2O):n(CeO2):n(2-methylimidazole)” in step 1) from 1:2:10:10 to 3:5:10:10;

[0094] That is, the amount of Co(NO3)2·6H2O used is 1.8 mmol, the amount of Zn(NO3)2·6H2O used is 3.0 mmol, the amount of CeO2 used is 6.0 mmol, and the amount of 2-methylimidazole used is 6.0 mmol.

[0095] The rest is the same as in Example 1.

[0096] The yield of stabilized phenyltrichlorosilane was 76.5%.

[0097] Example 4-1: Compared to Example 1, the following changes are made:

[0098] The stirring time in step 1.2) is changed from 6h to 8h, which is the same as in Example 1.

[0099] The yield of stabilized phenyltrichlorosilane was 85.3%.

[0100] Example 4-2: Compared to Example 1, the following changes are made:

[0101] The stirring time in step 1.2) is changed from 6h to 10h, which is the same as in Example 1.

[0102] The yield of stabilized phenyltrichlorosilane was 89.7%.

[0103] Example 4-3: Compared to Example 1, the following changes are made:

[0104] The stirring time in step 1.2) is changed from 6h to 12h, which is the same as in Example 1.

[0105] The yield of stabilized phenyltrichlorosilane was 87.6%.

[0106] Example 5-1: A method for preparing phenylmethyldichlorosilane using methyldichlorosilane and chlorobenzene;

[0107] Steps 1 and 2 are the same as in Example 4-2.

[0108] 3. Feeding and Discharging

[0109] The reaction pressure inside the fixed-bed reactor 22 is controlled to be stable at 0.6 MPa.

[0110] Maintain the temperature of the preheating vaporization chamber 19 at 240℃ and the temperature of the fixed bed reactor 22 at 250℃;

[0111] Chlorobenzene was introduced at a rate of 0.005 L / h, and methyldichlorosilane was introduced at a rate of 0.003 L / h.

[0112] The feed volume hourly space velocity is 350 h⁻¹ -1 ,

[0113] The reaction formula is

[0114] The rest are the same as step 3 in Example 1.

[0115] The product composition was detected every 5 minutes using an online gas phase detection and evaluation device. After 30 minutes of reaction, the reaction was stable. After stabilization, the amount of methyl dichlorosilane was 0.05525 g every 1 minute of reaction, and 0.06187 g of the target product phenyl methyl dichlorosilane was obtained, with a yield of 67.4%.

[0116] Example 5-2: A method for preparing phenyldimethylchlorosilane using dimethylchlorosilane and chlorobenzene.

[0117] Steps 1 and 2 are the same as in Example 4-2.

[0118] 3. Feeding and Discharging

[0119] The reaction pressure inside the fixed-bed reactor 22 is controlled to be stable at 0.6 MPa.

[0120] Maintain the temperature of the preheating vaporization chamber 19 at 290℃ and the temperature of the fixed bed reactor 22 at 300℃;

[0121] Chlorobenzene was introduced at a rate of 0.005 L / h, and dimethylchlorosilane was introduced at a rate of 0.004 L / h.

[0122] The feed volume hourly space velocity is 425 h⁻¹. -1 ,

[0123] The reaction formula is

[0124] The rest are the same as step 3 in Example 1.

[0125] The product composition was detected every 5 minutes using an online gas phase detection and evaluation device. After 30 minutes of reaction, the reaction was stable. After stabilization, the amount of dimethylchlorosilane was 0.05708 g every 1 minute of reaction, and 0.07374 g of the target product phenyl dimethylchlorosilane was obtained, with a yield of 71.6%.

[0126] Example 5-3: A method for preparing diphenyldichlorosilane using dichlorodihydrosilane and chlorobenzene;

[0127] Steps 1 and 2 are the same as in Example 4-2.

[0128] 3. Feeding and Discharging

[0129] The reaction pressure inside the fixed-bed reactor 22 is controlled to be stable at 0.7 MPa.

[0130] Maintain the temperature of the preheating vaporization chamber 19 at 290℃ and the temperature of the fixed bed reactor 22 at 300℃;

[0131] Chlorobenzene is introduced at a rate of 0.005 L / h, and dichlorosilane is introduced at a rate of 0.003 L / h.

[0132] The feed volume hourly space velocity is 375 h⁻¹. -1

[0133] The reaction formula is

[0134] The rest are the same as step 3 in Example 1.

[0135] The product composition was detected every 5 minutes using an online gas phase detection and evaluation device. After 30 minutes of reaction, the reaction was stable. After stabilization, the amount of dichlorosilane used was 0.06250 g every 1 minute of reaction, and 0.09929 g of the target product diphenyldichlorosilane was obtained, with a yield of 58.9%.

[0136] Experiment 1, Stability

[0137] Repeating Examples 4-2, the yield of phenyltrichlorosilane in the prepared ZnCo-ZIF / CeO2 catalyst remained at 86.9% after 48 hours of continuous use, indicating a long catalyst lifespan.

[0138] Comparative Example 1, compared to Examples 4-2, makes the following changes:

[0139] The preparation of nano CeO2 (1.1) is omitted, that is, commercially available CeO2 is used directly in step 1.2); the rest is the same as in Example 4-2.

[0140] The yield of stabilized phenyltrichlorosilane was only 58.6%, and the stability test results showed that it could only be maintained for 3 hours.

[0141] Comparative Example 2, compared to Example 1, makes the following changes:

[0142] The stirring time in step 1.2) is changed from 6 hours to 3 hours, which is the same as in Example 1.

[0143] The yield of stabilized phenyltrichlorosilane was 64.8%.

[0144] Comparative Example 3, compared to Examples 4-2, makes the following changes:

[0145] The addition of Co(NO3)2·6H2O was omitted in "1.2), Preparation of ZnCo-ZIF / CeO2", resulting in a catalyst of Zn-ZIF / CeO2, otherwise the process remained the same as in Example 4-2. The yield of stabilized phenyltrichlorosilane was only 35.7%.

[0146] Comparative Example 4, compared to Example 1, makes the following changes:

[0147] The reaction pressure in step 3 was changed from 0.4 MPa to 0.1 MPa, which is the same as in Example 1.

[0148] The yield of stabilized phenyltrichlorosilane was 52.2%.

[0149] Finally, it should be noted that the above examples are merely some specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments and many variations are possible. All variations that can be directly derived or conceived by those skilled in the art from the disclosure of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A method for preparing phenylchlorosilanes using a ZnCo-ZIF / CeO2 catalyst, characterized in that: A catalyst is added to a fixed-bed reactor, followed by purging with inert gas; Then, the chlorinated silanes and chlorobenzene used as raw materials are preheated and vaporized to obtain vaporized products, with a feed ratio of V. 含氯硅烷 :V 氯苯 =1:1.2~1.7; then the vaporized material is passed into a fixed-bed reactor packed with catalyst, with a volume hourly space velocity of 300~500 h⁻¹. -1 The reaction pressure is 0.1~1.0 MPa, and the reaction temperature is 200℃~350℃; The reaction product is condensed after exiting the fixed-bed reactor and then subjected to gas-liquid separation to obtain phenylchlorosilane as the product. The preparation method of ZnCo-ZIF / CeO2 catalyst is as follows: 1.1) Preparation of nano CeO2: Ce(NO3)3·6H2O and urea were added to deionized water and stirred to form a homogeneous mixture with a molar ratio of Ce(NO3)3·6H2O:urea = 1: (1.5±0.1). The homogeneous mixture was then transferred to a hydrothermal reactor and hydrothermally treated at 120-160℃ for 5±0.5 h. After centrifugation, the solid obtained by centrifugation was washed, dried, and then calcined at 600±50℃ for 5±0.5 h to obtain nano CeO2. 1.2) Preparation of ZnCo-ZIF / CeO2 Set the molar ratio n(Co(NO3)2·6H2O):n(Zn(NO3)2·6H2O):n(CeO2):n(2-methylimidazole) = 1~3:2~5:10:10; CeO2 powder was dispersed in anhydrous methanol, and then Zn(NO3)2·6H2O and Co(NO3)2·6H2O were added and ultrasonically dispersed. This dispersion was denoted as dispersion A. Dissolve 2-methylimidazole in anhydrous methanol, and denote this solution as solution B; Then, solution B was added to dispersion A and stirring was continued for 6-12 h. After centrifugation, the solid obtained by centrifugation was washed and dried to obtain the ZnCo-ZIF / CeO2 catalyst.

2. The method for preparing phenylchlorosilane according to claim 1, characterized in that: The chlorosilane is any of the following: trichlorosilane, phenylchlorosilane, phenyldichlorosilane, methyldichlorosilane, dimethyldichlorosilane, triethylchlorosilane, ethyltrichlorosilane, diethyldichlorosilane, methylvinylchlorosilane, vinyltrichlorosilane.

3. The method for preparing phenylchlorosilane according to claim 1 or 2, characterized in that: Liquid feed rate: 0.003–0.005 L / h.

4. The method for preparing phenylchlorosilane according to claim 3, characterized in that: In step 1.1): For every 10 mmol of Ce(NO3)3·6H2O, use 100±20 ml of deionized water; A homogeneous mixture was formed by stirring at room temperature for 1.5–2.5 h. The solid obtained by centrifugation was washed with ethanol and pure water, respectively, and then vacuum dried at 70±10℃ for 10~14h, followed by drying at 4~6℃·min. -1 The heating rate was increased to 600±50℃ and calcined for 5±0.5 h.

5. The method for preparing phenylchlorosilane according to claim 4, characterized in that... In step 1.2): For every 6.0 mmol CeO2, use 20±5 ml of anhydrous methanol; For every 6.0 mmol of 2-methylimidazole, use 20±5 ml of anhydrous methanol; The solid obtained by centrifugation was washed with ethanol and pure water respectively, and then dried under vacuum at 70±10℃ for 10~14h to obtain the ZnCo-ZIF / CeO2 catalyst.

6. The method for preparing phenylchlorosilane according to claim 5, characterized in that: In step 1.1), the hydrothermal treatment temperature is 160℃; In step 1.2), n(Co(NO3)2·6H2O):n(Zn(NO3)2·6H2O):n(CeO2):n(2-methylimidazole) = 1:2~5:10:10; stirring time 8~12h.

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