A bistriphenylsilyl chromate catalyst and its microwave-assisted preparation and application
The microwave-assisted preparation of bis(triphenylsilane) chromate catalysts solves the problems of long reaction time, low yield, and environmental pollution in existing technologies, achieving high-yield and high-purity catalyst preparation, which is suitable for ethylene polymerization, especially the production of high-density polyethylene.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHANGHAI LEADER CATALYST
- Filing Date
- 2023-02-16
- Publication Date
- 2026-06-16
Smart Images
Figure CN118496273B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of ethylene polymerization catalyst technology, and relates to a method for preparing bis(triphenylsilane) chromate catalyst using microwave and its application in ethylene polymerization. Background Technology
[0002] Polyethylene is a thermoplastic resin obtained by polymerizing ethylene. It is widely used in the production of films, injection molded products, hollow containers, pipes, wires, and cables, significantly improving people's quality of life. Its global production capacity exceeded 130 million tons per year at the end of 2021 and continues to grow. The core technology of ethylene polymerization is the catalyst. Titanium-based, nickel-based, and chromium-based catalysts can all catalyze ethylene polymerization, but titanium-based and nickel-based catalysts still require further improvement and development for industrial production. Therefore, chromium-based catalysts, which were the first to be applied to ethylene polymerization catalysis, still dominate the market. Among them, bis(triphenylsilane) chromate produces fewer byproducts during catalysis. Its products have the characteristics of both long and short branches, a wide relative molecular mass distribution, and excellent processing performance, and are widely used in the production of high-density polyethylene and linear low-density polyethylene.
[0003] The synthesis of bis(triphenylsilane) chromate mainly follows two routes depending on the starting materials: one uses triphenylsilanol and chromium trioxide as raw materials, and the other uses triphenylchlorosilane and potassium dichromate as raw materials. As early as 1958, Granchelli et al. reported in US Patent 2863891 that a reaction of triphenylsilanol and chromium trioxide with glacial acetic acid as solvent at 50°C for 10 minutes yielded bis(triphenylsilane) chromate with a yield of 85%. This method requires washing the product with a large amount of water until neutral, generating a large amount of industrial wastewater containing glacial acetic acid and chromic acid. Furthermore, the residual ppm levels of water and glacial acetic acid in the product are difficult to remove, reducing its catalytic performance in ethylene polymerization. To address the issue of glacial acetic acid as a solvent, Union Carbide in the United States switched to the aprotic solvent carbon tetrachloride, but the reaction efficiency was low, with a yield of only 60% (Baker LM, Carrick WLJOrg. Chem. 1970, 85, 774–776). In 1979, Jaroslar, in the original Czech patent (CS175856), used acetonitrile or butyronitrile as solvents, with yields only between 48% and 71%. In recent years, my country's Xiantao Green Chemical Industry Co., Ltd. has used any one or a mixture of two of the following solvents: alkanes, aromatics, and chlorinated hydrocarbons (chloroform or carbon tetrachloride), controlling the reaction at 40–100°C for 1–10 hours, achieving a yield of 80%. Due to the low solubility of chromium trioxide in the aforementioned aprotic solvents, the reaction time is long, the reaction temperature is high, and both the yield and purity are low. Compared with the synthesis process using triphenylsilanol and chromium trioxide as raw materials, the synthesis process using triphenylchlorosilane and potassium dichromate as raw materials disclosed in patent (SU 689192) and Chinese patent (CN 101665519A) has obvious limitations. For example, the reaction requires the use of protic solvent glacial acetic acid, the resulting product has a melting point of only 150-153°C and low purity, and a large amount of wastewater containing glacial acetic acid and chromic acid is generated, which pollutes the environment. Therefore, the industrial application of this process route is limited.
[0004] Microwave-assisted synthesis has become a common and efficient method for preparing compounds. Compared with traditional synthesis methods, microwave-assisted synthesis has advantages such as lower energy consumption, shorter reaction time, higher yield, and fewer side reactions. Therefore, microwave technology is widely used in catalyst preparation. However, to date, there are no reports on methods for preparing bis(triphenylsilane) chromate catalysts using microwave radiation. Summary of the Invention
[0005] The purpose of this invention is to provide a method for preparing bis(triphenylsilane) chromate catalysts using microwave and its application in ethylene polymerization, particularly in the preparation of high-density polyethylene.
[0006] The objective of this invention can be achieved through the following technical solutions:
[0007] A method for preparing a bis(triphenyl)silane chromate catalyst, comprising:
[0008] Triphenylsilanol, chromium trioxide, 3A molecular sieve and organic solvent were mixed and reacted under microwave conditions. After purification and separation, the bistriphenylsilane chromate catalyst was obtained.
[0009] The microwave conditions include: microwave output power of 100-800W and microwave frequency of 2000-3000MHz; the reaction conditions include: reaction temperature of 0-30℃ and reaction time of 10-30 minutes.
[0010] Furthermore, the molar ratio of triphenylsilanol to chromium trioxide is 1:(2-6).
[0011] Furthermore, the organic solvent is a chlorinated alkane solvent.
[0012] Furthermore, the chloroalkane solvent is one of dichloromethane, 1,1-dichloroethane, or 1,2-dichloroethane.
[0013] Furthermore, the amount of the chloroalkane solvent used is 3–9 mL / mmol triphenylsilanol.
[0014] Furthermore, the amount of the 3A molecular sieve used is 0.05–1 g / mmol triphenylsilanol.
[0015] Furthermore, the purification and separation process includes filtering the filtrate, heating and distilling to remove the solvent, obtaining crude bis(triphenylsilane) chromate, and then recrystallizing it with n-heptane to obtain the bis(triphenylsilane) chromate catalyst.
[0016] A bis(triphenyl)silane chromate catalyst is prepared by the method described above.
[0017] An application of a bis(triphenyl)silane chromate catalyst includes using the catalyst in an ethylene polymerization reaction.
[0018] Furthermore, the reaction conditions for the ethylene polymerization reaction include:
[0019] Using bis(triphenylsilane) chromate as the main catalyst and methylaluminoxane as the co-catalyst, ethylene is polymerized at 0–110 °C and 0.5–5.0 MPa. During polymerization, the molar ratio of metals in the co-catalyst to the main catalyst, Al / Cr, is 200–2000:1.
[0020] Compared with the prior art, the present invention has the following characteristics:
[0021] The synthesis method of this invention is simple to operate, has advanced technology, produces easily separable products, allows for the recycling of chromium trioxide, has low cost, and is easy to industrialize. The prepared bis(triphenyl)silane chromate has a yield of over 92% and a high purity of over 99%, exhibiting good catalytic activity in ethylene polymerization. Attached Figure Description
[0022] Figure 1 The infrared spectrum of the bis(triphenylsilane) chromate catalyst prepared in Example 1;
[0023] Figure 2 This is a schematic diagram of the 1H NMR spectrum of the bis(triphenylsilane) chromate catalyst prepared in Example 1.
[0024] Figure 3 The differential scanning calorimetry (DSC) curve of the bis(triphenylsilane) chromate catalyst prepared in Example 1 is shown below.
[0025] Figure 4 This is a thermogravimetric diagram of the bis(triphenyl)silane chromate catalyst prepared in Example 1;
[0026] Figure 5 This is a powder diffraction diagram of the bis(triphenyl)silane chromate catalyst prepared in Example 1. Detailed Implementation
[0027] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.
[0028] Example 1:
[0029] A method for preparing bis(triphenylsilane) chromate catalyst using microwave method:
[0030] Triphenylsilanol (1.38 g, 5 mmol), chromium trioxide (1.5 g, 15 mmol), 3A molecular sieve (0.5 g), and dichloromethane (30 mL) were added to a 100 mL polytetrafluoroethylene-lined reactor. The reactor was then placed in a microwave reactor, and the microwave output power was set to 400 W, the microwave frequency to 2450 MHz, and the reaction temperature to 20 °C. The reaction was stopped after 15 minutes, and the mixture was filtered to obtain filtrate A and residue A.
[0031] After recovering the dichloromethane solvent by atmospheric distillation, crude bis(triphenylsilane) chromate was obtained from filtrate A. It was then recrystallized from n-heptane (150 mL) to obtain orange-red needle-like bis(triphenylsilane) chromate crystals with a melting point of 159–160 °C and a yield of 93% (1.47 g, based on triphenylsilanol).
[0032] Deionized water was added to filter residue A, and the mixture was stirred at 60°C for 30 minutes. After filtration, filtrate B and filter residue B were obtained. Filter residue B was washed and dried to obtain 3A molecular sieve (0.5 g). Filtrate B was concentrated, dried and calcined to obtain chromium trioxide (1.22 g).
[0033] Infrared data (KBr, cm⁻¹) of microwave-assisted bis(triphenylsilane) chromate catalyst –1 ): 3069m, 1589m, 1427s, 1118s, 896s, 863s, 741w, 716m, 695m, 609w, 508s. See Figure 1 (Instrument model: Nicolet ESP 460)
[0034] 1H NMR data of microwave-assisted bis(triphenylsilane) chromate catalyst 1 ¹H NMR (300MHz, DMSO-d⁶) δ 7.39–7.56 (m, 30H). See [reference needed]. Figure 2 (Instrument model: Bruker AVANCE II 300M)
[0035] Example 2:
[0036] A method for preparing bis(triphenylsilane) chromate catalyst using a microwave method differs from Example 1 only in that:
[0037] The dosage of chromium trioxide is 3.0 g (30 mmol); the dosage of dichloromethane is 45 mL.
[0038] The microwave output power is 800W, the microwave frequency is 2450MHz, the reaction temperature is 0℃, and the reaction time is 30 minutes.
[0039] The rest is the same as in Example 1.
[0040] The product obtained is orange-red needle-like bis(triphenylsilane) chromate crystals with a melting point of 157–158 °C and a yield of 87% (1.38 g, based on triphenylsilanol).
[0041] Example 3:
[0042] A method for preparing bis(triphenylsilane) chromate catalyst using a microwave method differs from Example 1 only in that:
[0043] The microwave output power is 100W, the microwave frequency is 2450MHz, the reaction temperature is 30℃, and the reaction time is 10 minutes.
[0044] The rest is the same as in Example 1.
[0045] The product obtained is orange-red needle-like bis(triphenylsilane) chromate crystals with a melting point of 158–159 °C and a yield of 82% (1.29 g, based on triphenylsilanol).
[0046] Example 4:
[0047] A method for preparing bis(triphenylsilane) chromate catalyst using a microwave method differs from Example 1 only in that:
[0048] The microwave output power is 100W, the microwave frequency is 2450MHz, the reaction temperature is 30℃, and the reaction time is 20 minutes.
[0049] The rest is the same as in Example 1.
[0050] The product obtained is orange-red needle-like bis(triphenylsilane) chromate crystals with a melting point of 156–158 °C and a yield of 85% (1.35 g, based on triphenylsilanol).
[0051] Example 5:
[0052] A method for preparing bis(triphenylsilane) chromate catalyst using a microwave method differs from Example 1 only in that:
[0053] The amount of chromium trioxide used is 1.0 g (10 mmol); the amount of 3A molecular sieve used is 0.25 g; and the amount of dichloromethane used is 15 mL.
[0054] The microwave output power is 400W, the microwave frequency is 2450MHz, the reaction temperature is 25℃, and the reaction time is 30 minutes.
[0055] The rest is the same as in Example 1.
[0056] The product obtained is orange-red needle-like bis(triphenylsilane) chromate crystals with a melting point of 156–157 °C and a yield of 81% (1.28 g, based on triphenylsilanol).
[0057] Example 6:
[0058] A method for preparing bis(triphenylsilane) chromate catalyst using a microwave method differs from Example 1 only in that:
[0059] The amount of chromium trioxide used is 3.0 g (30 mmol); the amount of 3A molecular sieve used is 2.5 g; and the amount of dichloromethane used is 45 mL.
[0060] The microwave output power is 600W, the microwave frequency is 2450MHz, the reaction temperature is 20℃, and the reaction time is 15 minutes.
[0061] The rest is the same as in Example 1.
[0062] The product obtained is orange-red needle-like bis(triphenylsilane) chromate crystals with a melting point of 159–160 °C and a yield of 94% (1.49 g, based on triphenylsilanol).
[0063] Example 7:
[0064] A method for preparing bis(triphenylsilane) chromate catalyst using a microwave method differs from Example 1 only in that:
[0065] The amount of 3A molecular sieve used is 2.0 g; 1,1-dichloroethane is used instead of dichloromethane;
[0066] The microwave output power is 200W, the microwave frequency is 2450MHz, the reaction temperature is 20℃, and the reaction time is 30 minutes.
[0067] The rest is the same as in Example 1.
[0068] The product obtained is orange-red needle-like bis(triphenylsilane) chromate crystals with a melting point of 158–159 °C and a yield of 91% (1.44 g, based on triphenylsilanol).
[0069] Example 8:
[0070] A method for preparing bis(triphenylsilane) chromate catalyst using a microwave method differs from Example 1 only in that:
[0071] The amount of 3A molecular sieve used is 2.0 g; 40 mL of 1,2-dichloroethane is used instead of dichloromethane;
[0072] The microwave output power is 400W, the microwave frequency is 2450MHz, the reaction temperature is 20℃, and the reaction time is 10 minutes.
[0073] The rest is the same as in Example 1.
[0074] The product obtained is orange-red needle-like bis(triphenylsilane) chromate crystals with a melting point of 159–160 °C and a yield of 90% (1.42 g, based on triphenylsilanol).
[0075] Comparative Example 1: The Effects of Microwave Processing
[0076] A method for preparing bis(triphenylsilane)chromate catalyst:
[0077] Triphenylsilanol (1.38 g, 5 mmol), chromium trioxide (1.5 g, 15 mmol), 3A molecular sieve (0.5 g), and dichloromethane (30 mL) were added to a 100 mL four-necked flask. The mixture was reacted in the dark at 25 °C with mechanical stirring for 24 hours. The mixture was filtered to obtain filtrate A and residue A. After recovering the dichloromethane solvent by atmospheric distillation, crude bis(triphenylsilane) chromate was obtained from filtrate A. This crude product was then recrystallized from n-heptane (150 mL) to obtain orange-red needle-like bis(triphenylsilane) chromate crystals with a melting point of 155–157 °C and a yield of 62% (0.98 g, based on triphenylsilanol).
[0078] Comparative Example 2: Effects of Different Chromium Sources
[0079] A method for preparing bis(triphenylsilane)chromate catalyst:
[0080] Chromium trioxide was replaced with chromium trioxide (15 mmol) or other chromium salts (potassium dichromate, sodium dichromate, or basic chromium sulfate, 15 mmol), and added to a 100 mL polytetrafluoroethylene-lined reactor along with triphenylsilanol (1.38 g, 5 mmol), 3A molecular sieve (2.0 g), and dichloromethane (45 mL). The reactor was then placed in a microwave reactor, with the microwave output power set to 400 W, the microwave frequency to 2450 MHz, and the reaction temperature to 20 °C. After 30 minutes, the reaction was stopped, filtered, and filtrate A and residue A were obtained. After recovering the dichloromethane solvent by atmospheric distillation, filtrate A failed to yield a crude product containing bis(triphenylsilane) chromate.
[0081] Example 9:
[0082] Characterization of the bis(triphenyl)silane chromate catalyst of Example 1.
[0083] (1) Differential scanning calorimetry determination of bis(triphenylsilane)chromate catalyst
[0084] The microwave-prepared bis(triphenylsilane) chromate catalyst was analyzed using a PerkinElmer DSC-8500 differential thermal scanner, and compared with an imported bis(triphenylsilane) chromate catalyst (temperature range set at 25–200 °C, heating rate 10 °C / min, cooling rate 20 °C / min, second heating curve used). DSC analysis showed that both the microwave-prepared and imported bis(triphenylsilane) chromate catalysts exhibited similar endothermic peaks (160.2 °C). Figure 3 Differential scanning calorimetry curve of bis(triphenylsilane) chromate catalyst.
[0085] (2) Characterization of the thermal stability of the bis(triphenylsilane)chromate catalyst
[0086] The thermal stability of bis(triphenylsilane) chromate catalysts can be characterized by thermogravimetric analysis (TGA). The TGA of the microwave-prepared bis(triphenylsilane) chromate catalyst was measured using a NETZSCH / TG209F3 thermogravimetric analyzer (Germany), and compared with an imported bis(triphenylsilane) chromate catalyst (nitrogen atmosphere, temperature range 25–600 °C, heating rate 10 °C / min). The thermogravimetric curves showed that the microwave-prepared bis(triphenylsilane) chromate catalyst and the imported bis(triphenylsilane) chromate catalyst had very similar weight loss curves; when the temperature reached 170 °C, the structure began to decompose gradually. Figure 4 Thermogravimetric analysis of the bis(triphenylsilane) chromate catalyst.
[0087] (3) Powder diffraction characterization of the bis(triphenylsilane)chromate catalyst
[0088] The diffraction pattern of the microwave-prepared bis(triphenylsilane) chromate catalyst was determined using a Rigaku D / Max-2500 microscope (Japan), and compared with that of an imported bis(triphenylsilane) chromate catalyst (Cu Kα rake, fixed monochromator, tube voltage 40 kV, tube current 100 mA, scan rate 8° / min). The results show that the microwave-prepared bis(triphenylsilane) chromate catalyst and the imported bis(triphenylsilane) chromate catalyst are isomorphic and have similar diffraction peaks, but the microwave-prepared bis(triphenylsilane) chromate catalyst exhibits better crystallinity. Figure 5 Schematic diagram of powder diffraction of bis(triphenylsilane) chromate catalyst.
[0089] Example 10:
[0090] The bis(triphenyl)silane chromate catalyst prepared by microwave method in Example 1 was used to catalyze the production of polyethylene from ethylene.
[0091] A 300 mL Parr stainless steel reactor, equipped with an ethylene pressure control system, mechanical stirrer, and temperature controller, was continuously dried at 130 °C for 2 hours. While still hot, a vacuum was applied, and the reactor was purged three times with nitrogen. After drying, the reactor temperature was controlled and brought to the preset temperature using a heating mantle and circulating cooling water, and allowed to equilibrate for 30 minutes. A toluene solution containing 55 mL of freshly distilled toluene and 5.0 mL of the co-catalyst methylaluminoxane (MAO, 5.0 mmol) was sequentially injected into the reactor using a disposable syringe, while maintaining rapid stirring (stirrer speed constant at 800 rpm). After 10 minutes, a 40 mL toluene solution containing 3.17 mg (5.0 μmol) of bis(triphenylsilane)chromate catalyst was injected into the above reaction solution using a disposable syringe. The feed port screw was immediately tightened to seal, and ethylene was introduced. After reacting at 50 °C for 20 minutes, the ethylene vent valve, heating and stirring switches, and cooling water switch were closed. The reactor was allowed to return to room temperature, and the remaining ethylene gas was slowly released. Open the reactor and pour the reaction product into a 1000 mL beaker containing 200 mL of 10% hydrochloric acid in ethanol. After stirring for 1 hour, filter the mixture through a Buchner funnel to separate the white waxy polymer. Place the polymer in a fume hood overnight, then place it in a vacuum drying oven at 70°C for 12 hours. 1.83 g of product was obtained, with a polymerization activity of 1.83 × 10⁻⁶. 6 g PE / (mol-Cr·h).
[0092] Catalyst activity measurement method: polymer weight (g) / (catalyst dosage (mol)·polymerization time (h)).
[0093] Example 11:
[0094] The bis(triphenyl)silane chromate catalyst prepared by the microwave method in Example 1 was used to catalyze the production of polyethylene from ethylene. The only difference compared to Example 10 is:
[0095] The amount of co-catalyst methylaluminoxane (MAO) used was 10.0 mmol;
[0096] 1.27g of product was obtained, with a polymerization activity of 1.27×10⁻⁶. 6 g PE / (mol-Cr·h).
[0097] The remaining process is the same as in Example 10.
[0098] Example 12:
[0099] The bis(triphenyl)silane chromate catalyst prepared by the microwave method in Example 1 was used to catalyze the production of polyethylene from ethylene. The only difference compared to Example 10 is:
[0100] The amount of co-catalyst methylaluminoxane (MAO) used was 1.0 mmol;
[0101] 0.96g of product was obtained, with a polymerization activity of 0.96×10⁻⁶. 6 g PE / (mol-Cr·h).
[0102] The remaining process is the same as in Example 10.
[0103] Example 13:
[0104] The bis(triphenyl)silane chromate catalyst prepared by the microwave method in Example 1 was used to catalyze the production of polyethylene from ethylene. The only difference compared to Example 10 is:
[0105] The amount of co-catalyst methylaluminoxane (MAO) used was 10.0 mmol;
[0106] The reaction pressure is 0.5 MPa, and the reaction temperature is 0 °C.
[0107] 0.49g of product was obtained, with a polymerization activity of 0.49 × 10⁻⁶. 6 g PE / (mol-Cr·h).
[0108] The remaining process is the same as in Example 10.
[0109] Example 14:
[0110] The bis(triphenyl)silane chromate catalyst prepared by the microwave method in Example 1 was used to catalyze the production of polyethylene from ethylene. The only difference compared to Example 10 is:
[0111] The reaction pressure is 2 MPa, and the reaction temperature is 110℃;
[0112] 0.71g of product was obtained, with a polymerization activity of 0.71×10⁻⁶. 6 g PE / (mol-Cr·h).
[0113] The remaining process is the same as in Example 10.
[0114] Example 15:
[0115] The bis(triphenyl)silane chromate catalyst prepared by the microwave method in Example 1 was used to catalyze the production of polyethylene from ethylene. The only difference compared to Example 10 is:
[0116] The reaction pressure is 3 MPa, and the reaction temperature is 25°C.
[0117] 0.85g of product was obtained, with a polymerization activity of 0.85×10⁻⁶. 6 g PE / (mol-Cr·h).
[0118] The remaining process is the same as in Example 10.
[0119] Example 16:
[0120] The bis(triphenyl)silane chromate catalyst prepared by the microwave method in Example 1 was used to catalyze the production of polyethylene from ethylene. The only difference compared to Example 10 is:
[0121] The reaction pressure is 5 MPa;
[0122] 1.18g of product was obtained, with a polymerization activity of 1.18×10⁻⁶. 6 g PE / (mol-Cr·h).
[0123] The remaining process is the same as in Example 10.
[0124] Comparative Example 3:
[0125] A commercially available bis(triphenyl)silane chromate catalyst (Alpha Chemicals, Inc., USA, 98% purity) was used to catalyze the production of polyethylene from ethylene, and the catalytic reaction process was the same as in Example 10.
[0126] 1.71g of product was obtained, with a polymerization activity of 1.71×10⁻⁶. 6 g PE / (mol-Cr·h).
[0127] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.
Claims
1. A method for preparing a bis(triphenylsilane) chromate catalyst, characterized in that, The method includes: Triphenylsilanol, chromium trioxide, 3A molecular sieve and organic solvent were mixed and reacted under microwave conditions. After purification and separation, the bistriphenylsilane chromate catalyst was obtained. The microwave conditions include: microwave output power of 200~800W and microwave frequency of 2450MHz; the reaction conditions include: reaction temperature of 0~20℃ and reaction time of 15~30 minutes.
2. The method for preparing a bis(triphenylsilane) chromate catalyst according to claim 1, characterized in that, The molar ratio of triphenylsilanol to chromium trioxide is 1:(2~6).
3. The method for preparing a bis(triphenylsilane) chromate catalyst according to claim 1, characterized in that, The organic solvent is a chlorinated alkane solvent.
4. The method for preparing a bis(triphenylsilane) chromate catalyst according to claim 3, characterized in that, The chloroalkane solvent is one of dichloromethane, 1,1-dichloroethane, or 1,2-dichloroethane.
5. The method for preparing a bis(triphenylsilane) chromate catalyst according to claim 3, characterized in that, The amount of the chloroalkane solvent used is 3~9 mL / mmol triphenylsilanol.
6. The method for preparing a bis(triphenylsilane) chromate catalyst according to claim 1, characterized in that, The amount of the 3A molecular sieve used is 0.05~1 g / mmol triphenylsilanol.
7. The method for preparing a bis(triphenylsilane) chromate catalyst according to claim 1, characterized in that, The purification and separation process includes filtration to obtain the filtrate, heating and distilling to remove the solvent, obtaining crude bis(triphenylsilane) chromate, and then recrystallizing it with n-heptane to obtain the bis(triphenylsilane) chromate catalyst.