A kind of production method of octachlorotrisiloxane

Abstract

The invention discloses a production method of octachlorotrisiloxane, wherein the production device mainly comprises an alcoholysis reaction synthesizer, a high-temperature hydrogenation hot-washing reactor, an adsorption tower, an analytical tower, a primary distillation separation tower, a secondary distillation separation tower, a tail gas recovery device, and a product storage tank; raw material 5N-grade trichlorosilane and tert-butyl alcohol are added to the alcoholysis reaction synthesizer for alcoholysis reaction to obtain an alcoholysis reaction mixture, the alcoholysis reaction mixture enters the high-temperature hydrogenation hot-washing reactor, and the obtained hydrogenation hot-washing reactant is subjected to two distillation separations to obtain high-purity octachlorotrisiloxane. Through the production method of octachlorotrisiloxane of the present invention, the basic research in the experiment is amplified to engineering-scale production to achieve mass production; in actual production, each quality link is strictly controlled, the product purity is improved, the application level in the relevant scientific field is reached, and the sustainable development of relevant industries in my country is promoted.

Description

Technical Field

[0001] The invention relates to the field of organosilicon compounds, and in particular to a method for producing octachlorotrisiloxane. Background Art

[0002] Octachlorotrisiloxane is an important organosilicon compound with a unique chemical structure of silicon-oxygen-silicon chain. This unique structure gives octachlorotrisiloxane organic chemical stability and high temperature resistance, making it show great potential in the synthesis of other silicon-containing compounds. As an important organosilicon, trioctachlorotrisiloxane plays a key role in many links such as chemical synthesis, material preparation, chemical industry and medicine. Its application in the field of materials science has made an important contribution to the development of this high-tech industry.

[0003] At present, domestic and foreign companies producing octachlorotrisiloxane have not disclosed the relevant production process, and industrial large-scale production has not yet been achieved in China. For octachlorotrisiloxane, which plays an important role in the high-tech field, it is urgent to develop a high-purity octachlorotrisiloxane production process that can achieve mass production. Summary of the invention

[0004] The present invention aims to provide a production method of octachlorotrisiloxane, fill the production capacity gap of octachlorotrisiloxane in my country, and improve the product quality to the application level in the field of material science.

[0005] The purpose of the present invention is implemented by the following technical scheme: a method for producing octachlorotrisiloxane, characterized in that it comprises the following steps:

[0006] Alcoholysis reaction: The raw material 5N grade high-purity trichlorosilane and tert-butyl alcohol are subjected to alcoholysis reaction at a mass ratio of 18-25:1, the reaction temperature is 75℃-85℃, and the pressure is 0.3-0.35Mpa to obtain R-Si-Cl x and alcoholysis byproducts, where R is -OH, CH 3- 、(CH3) 2- , (CH3)3-, one or more of, x is 0, 1, 2, 3 or more;

[0007] Hydrogenation hot washing reaction: R-Si-Cl obtained by alcoholysis x The hydrogenation hot washing reaction is carried out with hydrogen at a molar ratio of 2.5-3:1, the hydrogenation hot washing reaction temperature is 650-850°C, and the reaction pressure is 0.5-0.65Mpa to obtain O x -Si y -Cl z and a byproduct of a hydrogenation hot washing reaction, wherein x is one or more of 1 and 2, y is one or more of 1, 2, and 3, and z is one or more of 5, 6, 7, and 8;

[0008] Primary distillation: O x -Si y -Cl z After a primary distillation separation, the primary product and the primary distillation by-product are obtained, and the primary distillation temperature is set at 65°C-72°C and the pressure is 0.45-0.55Mpa;

[0009] Second distillation: The primary product obtained by the first distillation separation is subjected to second distillation separation to obtain octachlorotrisiloxane and tail gas, and the second distillation temperature is set at 78°C-85°C and the reaction pressure is 0.1-0.15Mpa;

[0010] Storage: The octachlorotrisiloxane obtained by distillation again is injected into the storage tank.

[0011] Furthermore, the purity of hydrogen in the hydrogenation hot washing reaction is 6N grade.

[0012] Furthermore, the byproducts of the hydrogenation hot washing reaction are separated by adsorption to obtain hydrogen chloride gas, and the hydrogen chloride gas re-participates in the hydrogenation hot washing reaction.

[0013] Furthermore, the primary distillation by-product is subjected to adsorption separation to obtain hydrogen chloride gas, and the hydrogen chloride gas is re-participated in the hydrogenation hot washing reaction.

[0014] The advantages of the present invention are as follows: through the production method of octachlorotrisiloxane of the present invention, basic research in experiments is enlarged to engineering-scale production to achieve mass production; in actual production, each quality link is strictly controlled, the purity of the product is improved, the application level in the relevant scientific field is reached, and the sustainable development of relevant industries in my country is promoted. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 It is a schematic diagram of the production process of the present invention;

[0017] Figure 2 is the chromatogram of octachlorotrisiloxane of the present invention;

[0018] Figure 3 1 is the mass spectrum of octachlorotrisiloxane of the present invention.

[0019] In the figure: 1. Alcoholysis reaction synthesizer, 2. High-temperature hydrogenation hot washing reactor, 3. Adsorption tower, 4. Primary distillation separation tower, 5. Secondary distillation separation tower, 6. Tail gas recovery device, 7. Product storage tank, 8. Analysis tower. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] like Figure 1 As shown, the octachlorotrisiloxane production device involved in the present invention mainly includes an alcoholysis reaction synthesizer 1, a high-temperature hydrogenation hot washing reactor 2, an adsorption tower 3, a desorption tower 8, a primary distillation separation tower 4, a secondary distillation separation tower 5, a tail gas recovery device 6, and a product storage tank 7.

[0022] For the raw material high-purity trichlorosilane, trichlorosilane produced from polysilicon can be used as the main raw material, and the high-purity trichlorosilane is purified to 4-5N (above 99.99%) through a packing tower. The temperature of the purification packing tower is controlled at 100℃-105℃, and the pressure is controlled at 0.6-0.65Mpa.

[0023] Embodiment 1:

[0024] This embodiment provides a method for producing octachlorotrisiloxane, comprising the following steps:

[0025] Alcoholysis reaction: The raw material 5N grade trichlorosilane is injected into the tert-butyl alcohol alcoholysis reaction synthesis tower and tert-butyl alcohol (ethyl-methyl-2-propanol) for alcoholysis reaction. The mass ratio of the raw material 5N grade trichlorosilane to tert-butyl alcohol in the alcoholysis reaction is 25:1. The reaction temperature of the tert-butyl alcohol alcoholysis reaction synthesis tower is set to 85°C and the pressure is set to 0.35Mpa; R-Si-Cl x and alcoholysis byproducts, where R is -OH, CH 3- 、(CH3) 2- 、(CH3) 3- One or more of, x is one or more of 0, 1, 2, 3; in this embodiment, R-Si-Cl x It is a mixture of OHSiCl3, CH3SiCl3, (CH3)2SiCl2, and (CH3)3SiCl; the by-product of the alcoholysis reaction is hydrogen chloride gas, in which the hydrogen chloride gas continues to participate in the reaction.

[0026] Hydrogenation hot washing reaction: R-Si-Cl obtained by alcoholysis reaction xEntering the hydrogenation reactor, the hydrogenation reactor is preferably a vapor deposition CVD reactor. In the hydrogenation hot washing reaction, the molar ratio of the alcoholysis reaction mixture (based on the silicon element entering the alcoholysis reaction synthesizer) and hydrogen is 3:1. The temperature of the high-temperature hydrogenation hot washing reactor 2 is 850°C and the reaction pressure is 0.65Mpa. After adding hydrogen with a purity of 6N grade for hydrogenation hot washing reaction, under the action of high temperature, the OH bond and the CH bond will be broken and reorganized, and the oxygen atoms after dechaining are easy to combine with silicon to form organic alkoxy substances to obtain O x -Si y -Cl z and hydrogenation hot washing reaction byproducts, wherein x is one or more of 1 and 2, y is one or more of 1, 2, and 3, and z is one or more of 5, 6, 7, and 8; in this embodiment, x -Si y -Cl z It is a mixture of OSiCl3, OSi2Cl6, O2Si2Cl5, O3Si3Cl7, and O2Si3Cl8 (octachlorotrisiloxane); the by-products of the hydrogenation hot washing reaction obtained at the same time include hydrogen chloride gas and methane gas.

[0027] The by-products of the hydrogenation hot washing reaction enter the adsorption tower 3, which is preferably a packed tower. The reaction temperature of the adsorption tower 3 is -68°C and the reaction pressure is 1.3Mpa. After the adsorbent in the adsorption tower 3 is saturated, it is transferred to the analysis tower 8 for desorption and regeneration to restore the adsorption capacity of the adsorbent, and then it is sent back to the adsorption tower 3 for continued use; the reaction temperature of the analysis tower 8 is 110°C and the reaction pressure is 1.3Mpa. In this embodiment, the technology of similar dissolution between molecules, mutual fusion between polar molecules, and separation of polar molecules and non-polar molecules is adopted to separate the hydrogen chloride gas in the by-products of the hydrogenation hot washing reaction, and the hydrogen chloride gas is returned to the high-temperature hydrogenation hot washing reactor 2 to participate in the hydrogenation hot washing reaction.

[0028] Primary distillation: O obtained after hydrogenation hot washing reaction x -Si y -Cl z (a combination of one or more compounds) enters a primary distillation separation tower 4, wherein the primary distillation separation tower 4 is preferably a packed tower, and the temperature in the primary distillation separation tower 4 is set to 72° C. and the pressure is 0.55 MPa; the primary distillation separation tower 4 removes the by-products of the hydrogenation hot washing reaction to obtain a primary distillation initial product, and the primary distillation initial product includes octachlorotrisiloxane, chlorosilane (trichlorosilane, dichlorodihydrosilane), and hexachlorodisiloxane.

[0029] The gas in the primary distillation by-product enters the adsorption tower 3, which is preferably a packed tower. The reaction temperature of the adsorption tower 3 is -68°C and the reaction pressure is 1.3Mpa. After the adsorbent in the adsorption tower 3 is saturated, it is transferred to the analysis tower 8 for desorption and regeneration to restore the adsorption capacity of the adsorbent, and then it is sent back to the adsorption tower 3 for continued use; the reaction temperature of the analysis tower 8 is 110°C and the reaction pressure is 1.3Mpa. In this embodiment, the technology of similar dissolution between molecules, mutual fusion between polar molecules, and separation of polar molecules and non-polar molecules is adopted to separate the hydrogen chloride gas in the primary distillation by-product during the reaction process, and the hydrogen chloride gas is returned to the high-temperature hydrogenation hot washing reactor 2 to participate in the hydrogenation hot washing reaction.

[0030] Second distillation: The primary product obtained from the first distillation enters the second distillation separation tower 5 for second distillation separation. The temperature in the second distillation separation tower 5 is 85° C. and the pressure is 0.15 MPa. Compared with octachlorotrisiloxane, chlorosilane (trichlorosilane, dichlorodihydrosilane) and hexachlorodisiloxane in the primary product are light components. The second distillation separation tower 5 is preferably a packed tower.

[0031] Storage: After distillation and separation again, octachlorotrisiloxane is obtained in the bottom of the tower. The purity of the component can reach 99.955% after testing. The octachlorotrisiloxane is loaded into product storage tank 7.

[0032] Recovery: The mixed tail gas of chlorosilane (trichlorosilane, dichlorosilane) and hexachlorodisiloxane discharged from the top of the secondary distillation separation tower 5 enters the tail gas recovery device 6.

[0033] Embodiment 2:

[0034] This embodiment provides a method for producing octachlorotrisiloxane, comprising the following steps:

[0035] Alcoholysis reaction: The raw material 5N grade trichlorosilane is injected into the tert-butyl alcohol alcoholysis reaction synthesis tower and tert-butyl alcohol (ethyl-methyl-2-propanol) for alcoholysis reaction. The mass ratio of the raw material 5N grade trichlorosilane to tert-butyl alcohol in the alcoholysis reaction is 20:1. The reaction temperature of the tert-butyl alcohol alcoholysis reaction synthesis tower is set at 80°C and the pressure is set at 0.32Mpa; R-Si-Cl x and alcoholysis byproducts, where R is -OH, CH 3- 、(CH3) 2- 、(CH3) 3- One or more of, x is one or more of 0, 1, 2, 3; in this embodiment, R-Si-Cl x It is a mixture of OHSiCl3, CH3SiCl3, (CH3)2SiCl2, and (CH3)3SiCl; the by-product is hydrogen chloride gas, which continues to participate in the reaction.

[0036] Hydrogenation hot washing reaction: R-Si-Cl obtained by alcoholysis reaction x Entering the hydrogenation reactor, the hydrogenation reactor is preferably a vapor deposition CVD reactor. In the hydrogenation hot washing reaction, the molar ratio of the alcoholysis reaction mixture (based on the silicon element entering the alcoholysis reaction synthesizer) and hydrogen is 2.7:1. The temperature of the high-temperature hydrogenation hot washing reactor 2 is 750°C and the reaction pressure is 0.6Mpa. After adding hydrogen with a purity of 6N grade for hydrogenation hot washing reaction, under the action of high temperature, the OH bond and the CH bond will be broken and reorganized, and the oxygen atoms after dechaining are easy to combine with silicon to form organic alkoxy substances to obtain O x -Si y -Cl z and hydrogenation hot washing reaction byproducts, wherein x is one or more of 1 and 2, y is one or more of 1, 2, and 3, and z is one or more of 5, 6, 7, and 8; in this embodiment, x -Si y -Cl z It is a mixture of OSiCl3, OSi2Cl6, O2Si2Cl5, O3Si3Cl7, and O2Si3Cl8 (octachlorotrisiloxane); the by-products of the hydrogenation hot washing reaction obtained at the same time include hydrogen chloride gas and methane gas.

[0037] The adsorption tower 3 is preferably a packed tower, and the reaction temperature of the adsorption tower 3 is -65°C and the reaction pressure is 1.0Mpa. After the adsorbent in the adsorption tower 3 is saturated, it is transferred to the analysis tower 8 for desorption and regeneration to restore the adsorption capacity of the adsorbent, and then sent back to the adsorption tower 3 for continued use; the reaction temperature of the analysis tower 8 is 100°C and the reaction pressure is 1.0Mpa. In this embodiment, the technology of similar dissolution between molecules, mutual fusion between polar molecules, and separation of polar molecules and non-polar molecules is adopted to separate the hydrogen chloride gas in the by-product of the hydrogenation hot washing reaction during the reaction process, and the hydrogen chloride gas is returned to the high-temperature hydrogenation hot washing reactor 2 to participate in the hydrogenation hot washing reaction.

[0038] Primary distillation: O obtained after hydrogenation hot washing reaction x -Si y -Cl z (a combination of one or more compounds) enters a primary distillation separation tower 4, which is preferably a packed tower, and the temperature in the primary distillation separation tower 4 is set to 70° C. and the pressure is 0.5 MPa; the primary distillation separation tower 4 removes the by-products of the hydrogenation hot washing reaction to obtain a primary product, which includes octachlorotrisiloxane, chlorosilane (trichlorosilane, dichlorodihydrosilane), and hexachlorodisiloxane.

[0039] The gas in the primary distillation by-product enters the adsorption tower 3, which is preferably a packed tower. The reaction temperature of the adsorption tower 3 is -65°C and the reaction pressure is 1.0 MPa. After the adsorbent in the adsorption tower 3 is saturated, it is transferred to the analysis tower 8 for desorption and regeneration to restore the adsorption capacity of the adsorbent, and then sent back to the adsorption tower 3 for continued use; the reaction temperature of the analysis tower 8 is 100°C and the reaction pressure is 1.0 MPa. In this embodiment, the technology of similar dissolution between molecules, mutual fusion between polar molecules, and separation of polar molecules and non-polar molecules is adopted to separate the hydrogen chloride gas in the primary distillation by-product during the reaction process, and the hydrogen chloride gas is returned to the high-temperature hydrogenation hot washing reactor 2 to participate in the hydrogenation hot washing reaction.

[0040] Second distillation: The primary product obtained from the first distillation enters the second distillation separation tower 5 for second distillation separation. The temperature in the second distillation separation tower 5 is 80° C. and the pressure is 0.12 MPa. Compared with octachlorotrisiloxane, chlorosilane (trichlorosilane, dichlorodihydrosilane) and hexachlorodisiloxane in the primary product are light components. The second distillation separation tower 5 is preferably a packed tower.

[0041] Storage: After distillation and separation again, the octachlorotrisiloxane obtained in the bottom of the tower has a component purity of 99.985% after testing. The octachlorotrisiloxane is loaded into product storage tank 7.

[0042] Recovery: The mixed tail gas of chlorosilane (trichlorosilane, dichlorosilane) and hexachlorodisiloxane discharged from the top of the secondary distillation separation tower 5 enters the tail gas recovery device 6.

[0043] Embodiment 3:

[0044] This embodiment provides a method for producing octachlorotrisiloxane, comprising the following steps:

[0045] Alcoholysis reaction: The raw material 5N grade trichlorosilane is injected into the tert-butyl alcohol alcoholysis reaction synthesis tower and tert-butyl alcohol (ethyl-methyl-2-propanol) for alcoholysis reaction. The mass ratio of the raw material 5N grade trichlorosilane to tert-butyl alcohol in the alcoholysis reaction is 18:1. The reaction temperature of the tert-butyl alcohol alcoholysis reaction synthesis tower is set to 75°C and the pressure is set to 0.3Mpa; R-Si-Cl x and alcoholysis byproducts, where R is -OH, CH 3- 、(CH3) 2- 、(CH3) 3- One or more of, x is one or more of 0, 1, 2, 3; in this embodiment, R-Si-Cl x It is a mixture of OHSiCl3, CH3SiCl3, (CH3)2SiCl2, and (CH3)3SiCl, and the by-product is hydrogen chloride gas, in which the hydrogen chloride gas continues to participate in the reaction.

[0046] Hydrogenation hot washing reaction: R-Si-Cl obtained by alcoholysis reaction x Enter the hydrogenation reactor, the hydrogenation reactor is preferably a vapor deposition CVD reactor, in the hydrogenation hot washing reaction, the alcoholysis reaction mixture (based on the silicon element entering the alcoholysis reaction synthesizer) and hydrogen are used in a molar ratio of 2.5:1, the temperature of the high-temperature hydrogenation hot washing reactor 2 is 650°C, and the reaction pressure is 0.5Mpa; after adding hydrogen with a purity of 6N grade for hydrogenation hot washing reaction, under the action of high temperature, the OH bond and the CH bond will be broken and reorganized, and the oxygen atoms after dechaining are easy to combine with silicon to form organic alkoxy substances, and O x -Si y -Cl z and hydrogenation hot washing reaction byproducts, wherein x is one or more of 1 and 2, y is one or more of 1, 2, and 3, and z is one or more of 5, 6, 7, and 8; in this embodiment, x -Si y -Cl z It is a mixture of OSiCl3, OSi2Cl6, O2Si2Cl5, O3Si3Cl7, and O2Si3Cl8 (octachlorotrisiloxane); the by-products of the hydrogenation hot washing reaction obtained at the same time include hydrogen chloride gas and methane gas.

[0047] The adsorption tower 3 is preferably a packed tower, and the reaction temperature of the adsorption tower 3 is -70°C and the reaction pressure is 1.5Mpa. After the adsorbent in the adsorption tower 3 is saturated, it is transferred to the analysis tower 8 for desorption and regeneration to restore the adsorption capacity of the adsorbent, and then sent back to the adsorption tower 3 for continued use; the reaction temperature of the analysis tower 8 is 115°C and the reaction pressure is 1.5Mpa. In this embodiment, the technology of similar dissolution between molecules, mutual fusion between polar molecules, and separation of polar molecules and non-polar molecules is adopted to separate the hydrogen chloride gas in the by-product of the hydrogenation hot washing reaction during the reaction process, and the hydrogen chloride gas is returned to the high-temperature hydrogenation hot washing reactor 2 to participate in the hydrogenation hot washing reaction.

[0048] Primary distillation: O obtained after hydrogenation hot washing reaction x -Si y -Cl z (a combination of one or more compounds) enters a primary distillation separation tower 4, which is preferably a packed tower, and the temperature in the primary distillation separation tower 4 is set to 65° C. and the pressure is 0.45 MPa; the primary distillation separation tower 4 removes the by-products of the hydrogenation hot washing reaction to obtain a primary product, which includes octachlorotrisiloxane, chlorosilane (trichlorosilane, dichlorodihydrosilane), and hexachlorodisiloxane.

[0049] The gas in the primary distillation by-product enters the adsorption tower 3, which is preferably a packed tower. The reaction temperature of the adsorption tower 3 is -70°C and the reaction pressure is 1.5 MPa. After the adsorbent in the adsorption tower 3 is saturated, it is transferred to the analysis tower 8 for desorption and regeneration to restore the adsorption capacity of the adsorbent, and then sent back to the adsorption tower 3 for continued use; the reaction temperature of the analysis tower 8 is 115°C and the reaction pressure is 1.5 MPa. In this embodiment, the technology of similar dissolution between molecules, mutual fusion between polar molecules, and separation of polar molecules and non-polar molecules is adopted to separate the hydrogen chloride gas in the primary distillation by-product during the reaction process, and the hydrogen chloride gas is returned to the high-temperature hydrogenation hot washing reactor 2 to participate in the hydrogenation hot washing reaction.

[0050] Second distillation: The primary product obtained from the first distillation enters the secondary distillation separation tower 5 for secondary distillation separation. The temperature in the secondary distillation separation tower 5 is 78° C. and the pressure is 0.1 MPa. Compared with octachlorotrisiloxane, chlorosilane (trichlorosilane, dichlorodihydrosilane) and hexachlorodisiloxane in the primary product are light components. The secondary distillation separation tower 5 is preferably a packed tower.

[0051] Storage: After distillation and separation again, the octachlorotrisiloxane obtained in the bottom of the tower has a component purity of 99.908% after testing. The octachlorotrisiloxane is loaded into product storage tank 7.

[0052] Recovery: The mixed tail gas of chlorosilane (trichlorosilane, dichlorosilane) and hexachlorodisiloxane discharged from the top of the secondary distillation separation tower 5 enters the tail gas recovery device 6.

[0053] Comparative Example 1:

[0054] This example provides a method for producing octachlorotrisiloxane. This comparative example is partially the same as Example 1, except that:

[0055] The feed mass ratio of trichlorosilane to tert-butanol was adjusted to 30:1. There was too much trichlorosilane as the raw material. When the secondary distillation tower maintained normal operating conditions (temperature and pressure remained at operating values), the light component trichlorosilane in the mixed liquid (octachlorotrisiloxane and trichlorosilane) in the bottom of the tower could not be completely evaporated. Finally, a part of the liquid trichlorosilane was mixed in the octachlorotrisiloxane, affecting the purity of the octachlorotrisiloxane component. The final purity of the octachlorotrisiloxane component was 72.472%.

[0056] Comparative Example 2:

[0057] This example provides a method for producing octachlorotrisiloxane. This comparative example is partially the same as Example 2, except that:

[0058] The reaction temperature in the high-temperature hydrogenation hot washing reactor 2 was adjusted to 400°C, the OH bonds and CH bonds were not completely broken, it was not easy to form silicon-oxygen bonds, and other substances (such as: oxy-silanes, oxy-siloxanes) would appear, and the purity of the obtained octachlorotrisiloxane component was 33.643%.

[0059] Comparative Example 3:

[0060] This example provides a method for producing octachlorotrisiloxane. This comparative example is partially the same as Example 3, except that:

[0061] The molar ratio of the alcoholysis reaction mixture (based on the silicon element entering the alcoholysis reaction synthesizer) and hydrogen in the high-temperature hydrogenation hot washing reactor 2 is adjusted to 1.5:1 (mol / mol). If the total amount of hydrogen is insufficient, the carbon atoms after the alcoholysis reaction will be excessive, which will affect the synthesis of the product. 3- 、(CH3) 2- 、(CH3) 3- It will directly synthesize with silicon, affecting the formation of the main product. The purity of the obtained octachlorotrisiloxane component is 61.427%.

[0062] Embodiment 4:

[0063] The octachlorotrisiloxane obtained in Example 1-3 was qualitatively and quantitatively analyzed by GC-MS (gas chromatography-mass spectrometry). The analysis results are as follows: Figure 2-3 shown.

[0064] Figure 2 The chromatographic peak of octachlorotrisiloxane is at 42.78 min, which proves the presence of the substance in this time period.

[0065] Figure 3 The mass spectrum fragment peak of octachlorotrisiloxane at time 42.78min was confirmed by analysis of the silicon, oxygen and chlorine atoms present therein. The mass spectrum peak of 400.1014 corresponded to the relative molecular mass, and was determined to be the production substance octachlorotrisiloxane.

[0066] The octachlorotrisiloxane product obtained in Example 1-3 was analyzed by ICP-OES instrument for the metal content impurities contained therein, and the following table 1 was obtained:

[0067] Table 1 Analysis of metal content impurities in octachlorotrisiloxane

[0068]

[0069] Embodiment 5:

[0070] The purity of the octachlorotrisiloxane component obtained by the process of Examples 1-3 and Comparative Examples 1-3 is compared in Table 2 below:

[0071] Table 2 Comparison of component purity of octachlorotrisiloxane

[0072]

[0073] By comparing the component purity of octachlorotrisiloxane obtained in Examples 1-3 and Comparative Examples 1-3, it can be concluded that the mass ratio between the raw materials trichlorosilane and tert-butyl alcohol, the temperature of the hydrogenation hot washing reaction, and the molar ratio of the alcoholysis reaction mixture and hydrogen have a great influence on the component purity of octachlorotrisiloxane.

[0074] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for producing octachlorotrisiloxane, characterized in that: The steps include: Alcoholysis reaction: The raw material 5N grade high-purity trichlorosilane and tert-butyl alcohol are subjected to alcoholysis reaction at a mass ratio of 18-25:1, the reaction temperature is 75℃-85℃, and the pressure is 0.3-0.35MPa to obtain R-Si-Cl x and alcoholysis byproducts, where R is -OH, CH 3-、 (CH3) 2- 、(CH3) 3- One or more of, x is one or more of 0, 1, 2, 3; Hydrogenation hot washing reaction: R-Si-Cl obtained by alcoholysis x The hydrogenation hot washing reaction is carried out with hydrogen at a molar ratio of 2.5-3:1, the hydrogenation hot washing reaction temperature is 650-850°C, and the reaction pressure is 0.5-0.65MPa to obtain O x -Si y -Cl z and hydrogenation hot washing reaction byproducts, wherein x is one or more of 1 and 2, y is one or more of 1, 2, and 3, and z is one or more of 5, 6, 7, and 8; Primary distillation: O x -Si y -Cl z After a primary distillation separation, the primary product and the primary distillation by-product are obtained, and the primary distillation temperature is set at 65°C-72°C and the pressure is 0.45-0.55MPa; Second distillation: The primary product obtained by the first distillation separation is subjected to second distillation separation to obtain octachlorotrisiloxane and tail gas, and the second distillation temperature is set at 78°C-85°C and the reaction pressure is 0.1-0.15MPa; Storage: The octachlorotrisiloxane obtained by distillation again is injected into the storage tank.

2. The method for producing octachlorotrisiloxane according to claim 1, characterized in that: The purity of hydrogen in the hydrogenation hot washing reaction is 6N grade.

3. The method for producing octachlorotrisiloxane according to claim 2, characterized in that: The byproducts of the hydrogenation hot washing reaction are separated by adsorption to obtain hydrogen chloride gas, and the hydrogen chloride gas is re-participated in the hydrogenation hot washing reaction.

4. The method for producing octachlorotrisiloxane according to claim 3, characterized in that: The primary distillation by-product is subjected to adsorption separation to obtain hydrogen chloride gas, and the hydrogen chloride gas is re-participated in the hydrogenation hot washing reaction.

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