A production system and production method of hexachlorodisiloxane

Abstract

The invention discloses a production system of hexachlorodisiloxane, which includes a reactor, a primary condensation system, a distillation system and a final condenser. A method for producing hexachlorodisiloxane, which includes the following steps: S1: reaction; S2: primary condensation; S3: distillation; S4: final condensation. Advantages: The invention utilizes silicon tetrachloride and anhydrous ethanol to react under the catalysis of a catalyst to produce hexachlorodisiloxane, and produces hydrogen chloride gas and methane as by-products. After primary condensation, the hydrogen chloride gas is discharged as a light component, and the liquid obtained by the primary condensation is separated and purified by a distillation system to obtain liquid hexachlorodisiloxane, and high-purity hexachlorodisiloxane can be obtained by reasonably controlling the raw material ratio and the reaction temperature.

Description

Technical Field

[0001] The invention relates to the technical field of hexachlorodisiloxane production, and in particular to a hexachlorodisiloxane production system and a production method thereof. Background Art

[0002] Hexachlorodisiloxane is an important organosilicon compound with a unique chemical structure of silicon-oxygen-silicon chain. This unique structure gives hexachlorodisiloxane excellent chemical stability and high temperature resistance. As a high-performance material, hexachlorodisiloxane plays a vital role in the aerospace field. Its application not only greatly improves the performance of aircraft and spacecraft, but also adds a layer of protection to the safety and reliability of these high-tech equipment. In terms of pharmaceutical synthesis, hexachlorodisiloxane also shows great potential in the research of drug delivery systems. It can improve the stability and targeted release efficiency of drugs, which brings new possibilities for precision treatment. Through these innovative applications, hexachlorodisiloxane not only demonstrates its potential as a new hope in the medical field, but also promotes the advancement of medical technology.

[0003] Hexachlorodisiloxane has shown great potential in future scientific research and industrial applications. As an important organosilicon material, hexachlorodisiloxane has broad application prospects in plastics, rubber, coatings, and electronic products. At present, hexachlorodisiloxane is mainly a by-product of the silicon-based materials industry. For example, patent CN202120823536.9 proposes a hexachlorodisiloxane and hexachlorodisiloxane recovery system in polysilicon production, which belongs to the field of polysilicon production waste liquid recovery technology and improves the recovery efficiency of hexachlorodisiloxane (hexachlorodisiloxane); however, the market stock of hexachlorodisiloxane obtained as a by-product of silicon-based materials is small and cannot meet market demand. Summary of the invention

[0004] The first object of the present invention is to provide a production system of hexachlorodisiloxane.

[0005] The second object of the present invention is to provide a method for producing hexachlorodisiloxane.

[0006] The first object of the present invention is implemented by the following technical scheme: a production system of hexachlorodisiloxane, which includes a reactor, a primary condensation system, a distillation system and a final-stage condenser, the inlet of the reactor is connected with a silicon tetrachloride feeding pipe and an anhydrous ethanol feeding pipe, the top outlet of the reactor is connected with the inlet of the primary condensation system, the liquid phase outlet of the primary condensation system is connected with the inlet of the distillation system, and the liquid phase outlet of the distillation system is connected with the inlet of the finished product storage tank; the gas phase outlet of the primary condensation system and the gas phase outlet of the distillation system are both connected with the inlet of the final-stage condenser, the liquid phase outlet of the final-stage condenser is connected with the inlet of the distillation system, and the gas phase outlet of the final-stage condenser is connected with a recovery pipe.

[0007] Furthermore, the distillation system includes a primary distillation tower, a primary tower top condenser, a secondary distillation tower, and a secondary tower top condenser. The liquid phase outlet of the primary condensation system and the liquid phase outlet of the final condenser are both connected to the inlet of the primary distillation tower. The tower top outlet of the primary distillation tower is connected to the heat medium inlet of the tower bottom reboiler of the secondary distillation tower. The heat medium outlet of the tower bottom reboiler of the secondary distillation tower is connected to the inlet of the primary tower top condenser. The liquid phase outlet of the primary tower top condenser is connected to the reflux port of the primary distillation tower. ; The bottom outlet of the first distillation tower is connected to the inlet of the second distillation tower, the bottom outlet of the second distillation tower is connected to the inlet of the finished product storage tank, the top outlet of the second distillation tower is connected to the inlet of the second tower top condenser, and the liquid phase outlet of the second tower top condenser is connected to the reflux port of the second distillation tower; the gas phase outlet of the first tower top condenser and the gas phase outlet of the second tower top condenser are both connected to the inlet of the final-stage condenser, and the liquid phase outlet of the final-stage condenser is connected to the reflux port of the secondary distillation tower.

[0008] Furthermore, the primary condensation system includes an air cooler, a primary water cooler, and a secondary water cooler connected in sequence, the liquid phase outlets of the air cooler, the primary water cooler, and the secondary water cooler are all connected to the inlet of the distillation system, and the exhaust port of the secondary water cooler is connected to the inlet of the final-stage condenser.

[0009] The second object of the present invention is implemented by the following technical scheme: a method for producing hexachlorodisiloxane, which comprises the following steps:

[0010] S1: Reaction

[0011] Adding silicon tetrachloride and anhydrous ethanol in a weight ratio of (30-42):(11-19) into a reactor, reacting under the catalysis of a catalyst, and obtaining a mixed gas after the reaction;

[0012] S2: Primary condensation

[0013] The mixed gas obtained in S1 is subjected to primary condensation to obtain a primary condensate and a primary condensed gas;

[0014] S3: Distillation

[0015] The primary condensate obtained in S2 is distilled to obtain a hexachlorodisiloxane product and a distillation gas;

[0016] S4: Final condensation

[0017] The primary condensed gas obtained by the primary condensation of S2 and the distilled gas obtained by the distillation of S3 are subjected to final condensation, and the final condensate obtained is sent back to S3 for circulation treatment.

[0018] Further, in said S1, the reaction temperature is 450-480°C and the pressure is 0.6-0.8MPa;

[0019] Furthermore, in S1, the catalyst is a boron-based Lewis acid.

[0020] Furthermore, in S2, the primary condensation includes the following process:

[0021] S2-1: The mixed gas obtained in S1 is air-cooled through an air cooler, and the liquid phase outlet temperature of the air cooler is controlled to be 75-85°C;

[0022] S2-2: send the gas discharged from the air cooler to the primary water cooler for primary water cooling, and control the liquid phase outlet temperature of the primary water cooler to 50-60°C;

[0023] S2-3: send the gas discharged from the primary water cooler to the secondary water cooler for secondary water cooling, and control the liquid phase outlet temperature of the secondary water cooler to 40-50°C;

[0024] The liquid phase discharged from the air cooler, the first-stage water cooler and the second-stage water cooler is the primary condensate.

[0025] Further, the S3 distillation includes the following process:

[0026] S3-1: The primary condensate obtained in S2 is firstly distilled through a primary distillation tower, wherein the temperature in the primary distillation tower is 90-100° C. and the pressure is 0.45-0.5 MPa, to obtain a primary distillation feed liquid;

[0027] S3-2: The primary distillation liquid obtained in S3-1 is passed through a secondary distillation tower for secondary distillation. The temperature in the secondary distillation tower is 75-85°C and the pressure is 0.25-0.35Mpa. The liquid discharged from the secondary distillation tower is the hexachlorodisiloxane product.

[0028] Furthermore, in S4, the temperature of the final stage condensate is controlled to be 20-30°C.

[0029] The invention has the advantages that silicon tetrachloride and anhydrous ethanol are reacted under the catalysis of a catalyst to produce hexachlorodisiloxane as a main substance, and hydrogen chloride gas and methane as main and by-products; after primary condensation, the hydrogen chloride gas is discharged as a light component; the liquid obtained by the primary condensation is separated and purified by a distillation system to obtain liquid hexachlorodisiloxane; and high-purity hexachlorodisiloxane can be obtained by reasonably controlling the raw material ratio and the reaction temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of the overall structure of Example 1.

[0031] Figure 2 The chromatogram of the product obtained in Example 2.

[0032] Figure 3 This is the mass spectrum peak diagram obtained in Example 2.

[0033] Reactor 1, primary condensation system 2, air cooler 21, primary water cooler 22, secondary water cooler 23, distillation system 3, primary distillation tower 31, primary tower top condenser 32, secondary distillation tower 33, secondary tower top condenser 34, final condenser 4, silicon tetrachloride feeding pipe 5, anhydrous ethanol feeding pipe 6, finished product storage tank 7. DETAILED DESCRIPTION

[0034] In the description of the present invention, it should be noted that, if the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, if the terms "first", "second", "third" appear, they are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0035] Example 1: Figure 1 As shown, a production system of hexachlorodisiloxane includes a reactor 1, a primary condensation system 2, a distillation system 3 and a final-stage condenser 4, the inlet of the reactor 1 is connected with a silicon tetrachloride feeding pipe 5 and an anhydrous ethanol feeding pipe 6, the top outlet of the reactor 1 is connected with the inlet of the primary condensation system 2, the liquid phase outlet of the primary condensation system 2 is connected with the inlet of the distillation system 3, and the liquid phase outlet of the distillation system 3 is connected with the inlet of a finished product storage tank 7; the gas phase outlet of the primary condensation system 2 and the gas phase outlet of the distillation system 3 are both connected with the inlet of the final-stage condenser 4, the liquid phase outlet of the final-stage condenser 4 is connected with the inlet of the distillation system 3, and the gas phase outlet of the final-stage condenser 4 is connected with a recovery pipe.

[0036] The distillation system 3 includes a primary distillation tower 31, a primary tower top condenser 32, a secondary distillation tower 33, and a secondary tower top condenser 34. The liquid phase outlet of the primary condensation system 2 and the liquid phase outlet of the final condenser 4 are both connected to the inlet of the primary distillation tower 31, the tower top outlet of the primary distillation tower 31 is connected to the heat medium inlet of the tower bottom reboiler of the secondary distillation tower 33, the heat medium outlet of the tower bottom reboiler of the secondary distillation tower 33 is connected to the inlet of the primary tower top condenser 32, and the liquid phase outlet of the primary tower top condenser 32 is connected to the reflux port of the primary distillation tower 31. The bottom outlet of the primary distillation tower 31 is connected with the inlet of the secondary distillation tower 33, the bottom outlet of the secondary distillation tower 33 is connected with the inlet of the finished product storage tank 7, the top outlet of the secondary distillation tower 33 is connected with the inlet of the secondary tower top condenser 34, and the liquid phase outlet of the secondary tower top condenser 34 is connected with the reflux port of the secondary distillation tower 33; the gas phase outlet of the primary tower top condenser 32 and the gas phase outlet of the secondary tower top condenser 34 are both connected with the inlet of the final-stage condenser 4, and the liquid phase outlet of the final-stage condenser 4 is connected with the reflux port of the secondary distillation tower 33.

[0037] The primary condensation system 2 includes an air cooler 21, a primary water cooler 22, and a secondary water cooler 23 connected in sequence. The liquid phase outlets of the air cooler 21, the primary water cooler 22, and the secondary water cooler 23 are all connected to the inlet of the distillation system 3, and the exhaust port of the secondary water cooler 23 is connected to the inlet of the final-stage condenser 4.

[0038] Production process:

[0039] It includes the following steps:

[0040] S1: Reaction

[0041] Silicon tetrachloride and anhydrous ethanol are added into a reactor 1 in a weight ratio of (30-42):(11-19), and reacted under the catalysis of a catalyst-boryl Lewis acid, at a reaction temperature of 450-480° C. and a pressure of 0.6-0.8 MPa, to obtain a mixed gas after the reaction;

[0042] Reaction mechanism: At room temperature, silicon tetrachloride reacts with anhydrous ethanol to form ethyl silicate (Si(OC2H5)4). As the reaction temperature rises, ethyl silicate will decompose. At normal pressure, it can decompose above 400°C. At a reaction pressure above 0.6MPa, the decomposition temperature is lower. Under certain conditions, chlorosilane will be decomposed by alcohol to form alkoxysilane. The reaction process is gradually changing. The (OC2H5)-Si in Si(OC2H5)4 is gradually disconnected, and the disconnected OC2H5 ions are replaced by chlorine atoms or hydrocarbon groups, that is, the following substances appear: Si(OC2H5)3Cl, CH3Si(OC2H5)2Cl, (CH3)2Si(OC2H5)Cl, (CH3)3SiCl, CH3SiCl3, CH3Si(OC2H5)Cl2, the alkoxy in the product will first be gradually replaced by hydrocarbon or chloride ions. When the temperature reaches above 450°C, the hydroxyl group breaks the HO bond under the action of high temperature and intermolecular action, and the hydrocarbon group breaks from silicon under the action of the catalyst, and the substance is reorganized. The chlorine atom, oxygen atom and silicon are combined to produce hexachlorodisiloxane. The reaction chemical formula is as follows:

[0043] SiCl4+C2H5OH→Si(OC2H5)4+HCl

[0044] Si(OC2H5)4+SiCl4+C2H5OH→Si(OC2H5)3Cl+HCl

[0045] Si(OC2H5)3Cl+SiCl4+C2H5OH→CH3Si(OC2H5)Cl2+CH3Si(OC2H5)Cl2+CH3Si(OC2H5)2Cl

[0046] CH3Si(OC2H5)Cl2+SiCl4+C2H5OH→CH3SiCl3+HCl+(CH3)3SiCl+(CH3)2Si(OC2H5)Cl

[0047] CH3SiCl3+C2H5OH→Si2OCl6+CH4+HCl

[0048] S2: Primary condensation

[0049] The mixed gas obtained in S1 is subjected to primary condensation to obtain a primary condensate;

[0050] In S2, primary condensation includes the following processes:

[0051] S2-1: The mixed gas obtained in S1 is air-cooled through an air cooler 21, and the liquid phase outlet temperature of the air cooler 21 is controlled to be 75-85°C;

[0052] S2-2: sending the gas discharged from the air cooler 21 to the primary water cooler 22 for primary water cooling, and controlling the liquid phase outlet temperature of the primary water cooler 22 to be 50-60° C.;

[0053] S2-3: sending the gas discharged from the primary water cooler 22 to the secondary water cooler 23 for secondary water cooling, and controlling the liquid phase outlet temperature of the secondary water cooler 23 to be 40-50° C.;

[0054] The liquid phase discharged from the air cooler 21, the primary water cooler 22 and the secondary water cooler 23 is all primary condensate.

[0055] S3: Distillation

[0056] The primary condensate obtained in S2 is distilled to obtain a hexachlorodisiloxane product;

[0057] S3 distillation includes the following processes:

[0058] S3-1: The primary condensate obtained in S2 is firstly distilled through a primary distillation tower 31, wherein the temperature in the primary distillation tower 31 is 90-100° C. and the pressure is 0.45-0.5 MPa, to obtain a primary distillation feed liquid;

[0059] S3-2: The primary distillation liquid obtained in S3-1 is subjected to secondary distillation through a secondary distillation tower 33. The temperature in the secondary distillation tower 33 is 75-85°C and the pressure is 0.25-0.35 MPa. The liquid discharged from the secondary distillation tower 33 is a hexachlorodisiloxane product, which is stored in a finished product storage tank 7.

[0060] S4: Final condensation

[0061] The gas discharged from the above-mentioned secondary water cooler 23, as well as the gas discharged from the first tower top condenser 32 and the second tower top condenser 34 are all sent to the final stage condenser 4 for final stage condensation, and the temperature of the final stage condensate is controlled to be 20-30°C. The obtained final stage condensate is sent back to S3 for circulation treatment.

[0062] Embodiment 2: A method for producing hexachlorodisiloxane by a production system of hexachlorodisiloxane, comprising the following steps:

[0063] S1: Reaction

[0064] Silicon tetrachloride and ethanol are added into the reactor in a weight ratio of 30:11, and reacted under the catalysis of a catalyst-boryl Lewis acid, the reaction temperature is 450°C, the pressure is 0.7MPa, and a mixed gas is obtained after the reaction;

[0065] S2: Primary condensation

[0066] The mixed gas obtained in S1 is subjected to primary condensation to obtain a primary condensate and a primary condensed gas;

[0067] In S2, primary condensation includes the following processes:

[0068] S2-1: The mixed gas obtained in S1 is air-cooled through an air cooler, and the liquid phase outlet temperature of the air cooler is controlled to be 80°C;

[0069] S2-2: send the gas discharged from the air cooler to the primary water cooler for primary water cooling, and control the liquid phase outlet temperature of the primary water cooler to 55°C;

[0070] S2-3: send the gas discharged from the primary water cooler to the secondary water cooler for secondary water cooling, and control the liquid phase outlet temperature of the secondary water cooler to 45°C;

[0071] The liquid phase discharged from the air cooler, the first-stage water cooler and the second-stage water cooler is the primary condensate.

[0072] S3: Distillation

[0073] The primary condensate obtained in S2 is distilled to obtain a hexachlorodisiloxane product and a distillation gas;

[0074] S3 distillation includes the following processes:

[0075] S3-1: The primary condensate obtained in S2 is firstly distilled through a primary distillation tower, where the temperature in the primary distillation tower is 95° C. and the pressure is 0.46 MPa, to obtain a primary distillation feed liquid;

[0076] S3-2: The primary distillation liquid obtained in S3-1 is passed through a secondary distillation tower for secondary distillation. The temperature in the secondary distillation tower is 80° C. and the pressure is 0.3 MPa. The liquid discharged from the secondary distillation tower is the hexachlorodisiloxane product.

[0077] S4: Final condensation

[0078] The primary condensed gas obtained by the primary condensation of S2 and the distilled gas obtained by the distillation of S3 are subjected to final condensation, and the temperature of the final condensate is controlled to be 25°C. The final condensate obtained is sent back to S3 for circulation treatment.

[0079] The hexachlorodisiloxane product obtained in Example 2 was subjected to chromatographic analysis to obtain Figure 2 The chromatogram shown in Figure 2 The chromatographic peak at 44.21 min was analyzed by mass spectrometry to obtain Figure 3 The mass spectrum peak diagram shown in FIG. 1 shows that the relative molecular mass of the product is 285.0109. Based on the composition of silicon atoms, chlorine atoms and oxygen atoms, it is concluded that the substance with a relative molecular mass of 285 is hexachlorodisiloxane.

[0080] In Examples 3 to 6, the overall production process is the same as that in Example 2, except that the weight ratio of silicon tetrachloride and anhydrous ethanol, reaction temperature and pressure are different. The specific differences are shown in the table below:

[0081]

[0082] Comparative Example 1: A method for producing hexachlorodisiloxane using a hexachlorodisiloxane production system, wherein the overall method steps are the same as those of Example 2, except that in S1, the reaction temperature is 200°C.

[0083] Comparative Example 2: A method for producing hexachlorodisiloxane using a hexachlorodisiloxane production system, wherein the overall method steps are the same as those of Example 2, except that in S1, the reaction temperature is 550°C.

[0084] Comparative Example 3: A method for producing hexachlorodisiloxane using a hexachlorodisiloxane production system, wherein the overall method steps are the same as those of Example 2, except that in S1, the weight ratio of silicon tetrachloride to ethanol is 20:18.

[0085] The metal impurities in the hexachlorodisiloxane products obtained in Examples 2 to 6 and Comparative Examples 1 to 3 were analyzed using an ICP-OES instrument, and the material components were analyzed by a chromatography-mass spectrometry instrument analyzer. The results are as follows:

[0086]

[0087] It can be seen from the above table that the purity of the hexachlorodisiloxane products obtained in Examples 2 to 6 is above 99%, while the purity of the hexachlorodisiloxane products obtained in Comparative Examples 1 to 3 is less than 60%. This is because in Comparative Example 1, when the temperature in the reactor is reduced to 200°C, the reaction rate of silicon tetrachloride is 40% of the normal reaction rate, the effect of the catalyst is weakened, the conversion rate of silicon tetrachloride is about 20% of the normal value, the content of the generated hexachlorodisiloxane is small, and silicate substances will be produced; in Comparative Example 2, when the reaction temperature in the reactor is increased to 550°C, the inhibitory effect of the catalyst on hydrogen free radicals begins to increase, the oxygen atoms are more active, and the excess oxygen atoms will form a variety of Si-O bonds with silicon, generating another substance-hexachlorotrisiloxane, and the content is higher than that of hexachlorodisiloxane; in Comparative Example 3, the raw material ratio is not appropriate, the raw material material reaction is not thorough, and the purity of hexachlorodisiloxane cannot meet the requirements. The present invention can obtain a high-purity hexachlorodisiloxane product by reasonably controlling the raw material ratio and reaction temperature to meet market demand.

Claims

1. A method for producing hexachlorodisiloxane, characterized in that: It includes the following steps: S1: Reaction Adding silicon tetrachloride and primary alcohol in a weight ratio of (30-42):(11-19) into a reactor, reacting under the catalysis of a catalyst, and obtaining a mixed gas after the reaction; S2: Primary condensation The mixed gas obtained in S1 is subjected to primary condensation to obtain a primary condensate; S3: Distillation The primary condensate obtained in S2 is distilled to obtain a hexachlorodisiloxane product; S4: Final condensation The gas produced after the primary condensation of S2 and the gas obtained after the rectification of S3 are subjected to final condensation, and the final condensate obtained is sent back to S3 for circulation treatment; In S1, the reaction temperature is 300-450°C and the pressure is 0.6-0.8Mpa; In the S1, the catalyst is a boron-based Lewis acid.

2. A method for producing hexachlorodisiloxane according to claim 1, characterized in that: In S2, the primary condensation includes the following process: S2-1: The mixed gas obtained in S1 is air-cooled through an air cooler, and the liquid phase outlet temperature of the air cooler is controlled to be 75-85°C; S2-2: send the gas discharged from the air cooler to the primary water cooler for primary water cooling, and control the liquid phase outlet temperature of the primary water cooler to 50-60°C; S2-3: send the gas discharged from the primary water cooler to the secondary water cooler for secondary water cooling, and control the liquid phase outlet temperature of the secondary water cooler to 40-50°C; The liquid phase discharged from the air cooler, the first-stage water cooler and the second-stage water cooler are all primary condensate.

3. A method for producing hexachlorodisiloxane according to claim 1, characterized in that: The S3 distillation includes the following process: S3-1: The primary condensate obtained in S2 is firstly distilled through a primary distillation tower, wherein the temperature in the primary distillation tower is 90-100° C. and the pressure is 0.45-0.5 MPa, to obtain a primary distillation feed liquid; S3-2: The primary distillation liquid obtained in S3-1 is passed through a secondary distillation tower for secondary distillation. The temperature in the secondary distillation tower is 75-85°C and the pressure is 0.25-0.35Mpa. The liquid discharged from the secondary distillation tower is the hexachlorodisiloxane product.

4. A method for producing hexachlorodisiloxane according to claim 1, characterized in that: In S4, the temperature of the final condensate is controlled to be 20-30°C.

5. A method for producing hexachlorodisiloxane according to claim 1, characterized in that: The primary alcohol is one or a combination of ethanol, n-propanol, and n-butanol.

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