Production method of hexachlorotrisiloxane

Abstract

The invention discloses a production method of hexachlorotrisiloxane. Production devices mainly comprise a reaction synthesizer, a condensation system, a rectification system, a final-stage condensation system and a storage system. The method comprises the following steps: reacting raw materials silicon tetrachloride and primary alcohol according to a certain ratio under the catalytic action of a boron Lewis acid catalyst in an environment that the reaction temperature is controlled to be 650-800 DEG C and the reaction pressure is controlled to be 0.6-0.8 MPa to obtain a mixed gas of hexachlorotrisiloxane and a by-product; and the high-purity hexachlorotrisiloxane is obtained after cooling of the condensation system and separation of the rectification system. The invention breaks through the blank of the production process of the hexachlorotrisiloxane in China, thereby eliminating the dependence of the demand of the hexachlorotrisiloxane product in China on foreign import, providing a stable production process, expanding the productivity of the hexachlorotrisiloxane, and realizing the production of the high-purity hexachlorotrisiloxane product. The problems of high-end industries in China are solved, and sustainable development of related industries in China is promoted.

Description

Technical Field

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

[0002] Hexachlorotrisiloxane is an important organosilicon compound. Its molecular structure contains a ring skeleton formed by three silicon atoms and three oxygen atoms, surrounded by six chlorine atoms. It has a unique chemical structure of silicon-oxygen-silicon chain. This unique structure gives hexachlorotrisiloxane chemical stability and high temperature resistance, making it show great potential in the synthesis of other silicon-containing compounds. In terms of physical properties, hexachlorotrisiloxane has a high boiling point and low vapor pressure, which enables it to remain stable at high temperatures. In terms of chemical properties, hexachlorotrisiloxane exhibits good corrosion resistance and non-flammability, which makes it widely used in industry.

[0003] Hexachlorotrisiloxane plays a vital role in the field of modern science and technology. Its application range is wide, covering many aspects from advanced material development to pharmaceutical synthesis. In the development of advanced materials, hexachlorotrisiloxane, as an important precursor or intermediate, provides a key chemical basis for the preparation of high-performance silicon-based materials. For example, in the aerospace field, it is used to manufacture lightweight, high-temperature resistant composite materials, which greatly improves the flight performance and safety of spacecraft. In addition, in pharmaceutical synthesis, hexachlorotrisiloxane can participate in the synthesis of a series of new drugs with important therapeutic value through its unique chemical reactivity, contributing to the progress of the medical field. Hexachlorotrisiloxane has shown great potential in future scientific research and industrial applications. As an important organosilicon material, hexachlorotrisiloxane has broad application prospects in plastics, rubber, coatings and electronic products.

[0004] However, the production process of hexachlorotrisiloxane, an organosilicon compound with a wide range of industrial applications, is relatively complicated. There are currently no companies in China that specialize in producing hexachlorotrisiloxane. The domestic demand for hexachlorotrisiloxane is basically imported from abroad, so many high-end companies in China often encounter problems with its price and supply. Due to the serious lack of production technology for hexachlorotrisiloxane in China, it is currently urgent to develop a process technology for producing hexachlorotrisiloxane to solve the problems faced by my country's high-end industry. Summary of the invention

[0005] The invention aims to provide a method for producing hexachlorotrisiloxane, which can fill the blank of the domestic production process technology of hexachlorotrisiloxane.

[0006] The purpose of the present invention is implemented by the following technical scheme: a method for producing hexachlorotrisiloxane, comprising the following steps: Reaction: silicon tetrachloride and primary alcohol are added into a reaction synthesizer in a mass ratio of 30-42:11-19, the reaction temperature is set to 650-800°C, the pressure is set to 0.6-0.8MPa, and a reaction is carried out under the action of a catalyst boron Lewis acid to obtain a reaction product; Primary condensation: The reaction product is subjected to primary condensation, and the outlet temperature of the process side of the condensation system is set to 40-50°C and the pressure is 0.6-0.8MPa to obtain primary condensate and non-condensable gas; Primary distillation: The primary condensate is subjected to primary distillation, the distillation temperature is set at 85-95°C, and the pressure is set at 0.25-0.35MPa to obtain primary distillation products of hexachlorotrisiloxane and mixed gas; Re-condensation: The non-condensable gas and mixed gas obtained by the initial condensation are re-condensed, and the inlet temperature of the process side of the final condensation system is 85~95℃, and the outlet temperature is 20~30℃; re-condensate and non-condensable gas are obtained; Secondary distillation: The condensate is subjected to secondary distillation, the distillation temperature is set to 85-95°C, and the pressure is set to 0.25-0.35MPa, to obtain secondary distillation products hexachlorotrisiloxane and mixed gas; Storage: The primary distillation product hexachlorotrisiloxane and the secondary distillation product hexachlorotrisiloxane enter the storage system.

[0007] Furthermore, the primary alcohol is a mixture of one or more of n-propanol, benzyl alcohol, isobutanol and n-butanol.

[0008] Furthermore, the mixed gas after the secondary distillation and the non-condensable gas after the re-condensation are discharged from the final condensation system and then recycled.

[0009] Advantages of the present invention: The present invention breaks through the blank of domestic hexachlorotrisiloxane production process, thereby eliminating the domestic demand for hexachlorotrisiloxane products and dependence on foreign imports, and at the same time provides a stable production process, expands the production capacity of hexachlorotrisiloxane, realizes the production of high-purity hexachlorotrisiloxane products, solves the problems faced by my country's high-end industries, and promotes the sustainable development of related industries in my country. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] 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.

[0011] Figure 1 It is a schematic diagram of the production process of the present invention; Figure 2 is the chromatogram of hexachlorotrisiloxane of the present invention; Figure 3 It is the mass spectrum of hexachlorotrisiloxane of the present invention.

[0012] Among them, 1. Reaction synthesizer; 2. Condensation system; 3. Distillation system; 4. Final condensation system; 5. Storage system. DETAILED DESCRIPTION

[0013] 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.

[0014] Embodiment 1: like Figure 1 As shown, the hexachlorotrisiloxane production device involved in the present invention mainly includes a reaction synthesizer 1, a condensation system 2, a distillation system 3, a final condensation system 4, and a storage system 5. The top of the reaction synthesizer 1 is connected to the air inlet of the condensation system 2 through a gas phase pipe, the bottom liquid outlet of the condensation system 2 is connected to the liquid inlet of the distillation system 3 through a liquid phase pipe, the top gas outlet of the condensation system 2 is connected to the air inlet of the final condensation system 4 through a gas phase pipe, the bottom liquid outlet of the final condensation system 4 is connected to the liquid inlet of the distillation system 3 through a liquid phase pipe, the top gas outlet of the distillation system 3 is connected to the gas inlet of the final condensation system 4 through a gas phase pipe, the top gas outlet of the final condensation system 4 is connected to an exhaust pipe, and the bottom liquid outlet of the distillation system 3 is connected to the liquid inlet of the storage system 5 through a liquid phase pipe.

[0015] Silicon tetrachloride and primary alcohol react in a certain proportion under a specific temperature and pressure environment, and are catalyzed by a boron Lewis acid catalyst to obtain hexachlorotrisiloxane. The reaction temperature is controlled at 650~800℃, and the reaction pressure is controlled at 0.6~0.8MPa.

[0016] The reaction equation is: SiCL4+R X CH2OH→Si3O3CL6+RSi(OR) X +HCL Wherein, the primary alcohol is a mixture of one or more of n-propanol, benzyl alcohol, isobutanol and n-butanol.

[0017] This embodiment provides a method for producing hexachlorotrisiloxane, comprising the following steps: Reaction: adding silicon tetrachloride and primary alcohol into a reaction synthesizer 1 at a mass ratio of 30-42:11-19, setting the temperature in the reaction synthesizer 1 to 650-800°C and the pressure to 0.6-0.8MPa, reacting under the action of a catalyst boron Lewis acid to obtain a reaction product, wherein the main components of the reaction product are hexachlorotrisiloxane, trichlorosilane, hydrogen chloride and unreacted raw silicon tetrachloride gas; Primary condensation: The reaction product is drawn out from the top gas outlet of the reaction synthesizer 1 and enters the condensation system 2 for primary condensation. The outlet temperature of the process side of the condensation system is set to 40-50°C and the pressure is 0.6-0.8MPa to obtain primary condensate and non-condensable gas. The non-condensable gas is mainly hydrogen chloride and some hexachlorotrisiloxane that has not been completely condensed. Primary distillation: The primary condensate is drawn from the bottom liquid outlet of the condensation system 2 and enters the distillation system 3 for primary distillation. The distillation temperature is set to 85-95°C and the pressure is set to 0.25-0.35MPa to obtain hexachlorotrisiloxane and a mixed gas as the primary distillation product. The main components of the mixed gas are hexachlorotrisiloxane, silicon tetrachloride and trichlorosilane. Secondary condensation: the non-condensable gas obtained by the initial condensation enters the final condensation system 4 through the top gas outlet of the condensation system 2 for secondary condensation, and the mixed gas obtained after the primary distillation enters the final condensation system 4 through the top gas outlet of the distillation system 3 for secondary condensation, and the process side inlet temperature of the final condensation system 4 is 85-95°C, and the outlet temperature is 20-30°C; secondary condensate and non-condensable gas are obtained, the main component of the secondary condensate is a mixed liquid of hexachlorotrisiloxane, silicon tetrachloride and trichlorosilane, and the main component of the non-condensable gas is the main component hydrogen chloride gas; Secondary distillation: The condensate is again distilled into the distillation system 3 from the bottom liquid outlet of the final condensation system 4 for secondary distillation. The distillation temperature is set to 85-95°C and the pressure is set to 0.25-0.35MPa to obtain hexachlorotrisiloxane and mixed gas as secondary distillation products; Storage: The primary distillation product hexachlorotrisiloxane and the secondary distillation product hexachlorotrisiloxane enter the storage system.

[0018] The hexachlorotrisiloxane in the reaction product is fully separated by re-condensation and secondary distillation to obtain high-purity hexachlorotrisiloxane.

[0019] The mixed gas after the secondary distillation and the non-condensable gas after the re-condensation are discharged from the gas outlet at the top of the final condensation system 4 for recovery and treatment.

[0020] Embodiment 2: This embodiment provides a method for producing hexachlorotrisiloxane, comprising the following steps: Reaction: silicon tetrachloride and n-propanol are added into the reaction synthesizer 1 in a mass ratio of 33:15, the temperature in the reaction synthesizer 1 is set to 650°C, the pressure is set to 0.6MPa, and a reaction product is obtained after a reaction occurs under the action of a catalyst boron Lewis acid, wherein the main components of the reaction product are hexachlorotrisiloxane, trichlorosilane, hydrogen chloride and unreacted raw material silicon tetrachloride gas; Primary condensation: The reaction product is drawn out from the top gas outlet of the reaction synthesizer 1 and enters the condensation system 2 for primary condensation. The outlet temperature of the process side of the condensation system is set to 40° C. and the pressure is 0.6 MPa to obtain primary condensate and non-condensable gas. The non-condensable gas is mainly hydrogen chloride and some hexachlorotrisiloxane that has not been completely condensed. Primary distillation: The primary condensate is drawn from the bottom liquid outlet of the condensation system 2 and enters the distillation system 3 for primary distillation. The distillation temperature is set to 85°C and the pressure is set to 0.25MPa to obtain hexachlorotrisiloxane and a mixed gas as the primary distillation product. The main components of the mixed gas are hexachlorotrisiloxane, silicon tetrachloride and trichlorosilane. Secondary condensation: the non-condensable gas obtained by the initial condensation enters the final condensation system 4 through the top gas outlet of the condensation system 2 for secondary condensation, and the mixed gas obtained after the primary distillation enters the final condensation system 4 through the top gas outlet of the distillation system 3 for secondary condensation, and the process side inlet temperature of the final condensation system 4 is 85° C., and the outlet temperature is 20° C.; secondary condensate and non-condensable gas are obtained, the main component of the secondary condensate is a mixed liquid of hexachlorotrisiloxane, silicon tetrachloride and trichlorosilane, and the main component of the non-condensable gas is the main component hydrogen chloride gas; Secondary distillation: The condensate is again distilled into the distillation system 3 from the bottom liquid outlet of the final condensation system 4 for secondary distillation. The distillation temperature is set to 85°C and the pressure is set to 0.25MPa to obtain hexachlorotrisiloxane and mixed gas as secondary distillation products; Storage: The primary distillation product hexachlorotrisiloxane and the secondary distillation product hexachlorotrisiloxane enter the storage system.

[0021] The hexachlorotrisiloxane in the reaction product is fully separated by re-condensation and secondary distillation to obtain high-purity hexachlorotrisiloxane with a purity of 99.995%.

[0022] The mixed gas after the secondary distillation and the non-condensable gas after the re-condensation are discharged from the gas outlet at the top of the final condensation system 4 for recovery and treatment.

[0023] Embodiment 3: This embodiment provides a method for producing hexachlorotrisiloxane, comprising the following steps: Reaction: silicon tetrachloride and n-propanol are added into the reaction synthesizer 1 in a mass ratio of 35:17, the temperature in the reaction synthesizer 1 is set to 700°C, the pressure is set to 0.7MPa, and a reaction product is obtained after a reaction occurs under the action of a catalyst boron Lewis acid, the main components of the reaction product are hexachlorotrisiloxane, trichlorosilane, hydrogen chloride and unreacted raw material silicon tetrachloride gas; Primary condensation: The reaction product is drawn out from the top gas outlet of the reaction synthesizer 1 and enters the condensation system 2 for primary condensation. The outlet temperature of the process side of the condensation system is set to 45° C. and the pressure is 0.7 MPa to obtain primary condensate and non-condensable gas. The non-condensable gas is mainly hydrogen chloride and some hexachlorotrisiloxane that has not been completely condensed. Primary distillation: The primary condensate is drawn from the bottom liquid outlet of the condensation system 2 and enters the distillation system 3 for primary distillation. The distillation temperature is set to 90° C. and the pressure is set to 0.3 MPa to obtain hexachlorotrisiloxane and a mixed gas as the primary distillation product. The main components of the mixed gas are hexachlorotrisiloxane, silicon tetrachloride and trichlorosilane. Secondary condensation: the non-condensable gas obtained by the initial condensation enters the final condensation system 4 through the top gas outlet of the condensation system 2 for secondary condensation, and the mixed gas obtained after the primary distillation enters the final condensation system 4 through the top gas outlet of the distillation system 3 for secondary condensation, and the process side inlet temperature of the final condensation system 4 is 90° C., and the outlet temperature is 25° C.; secondary condensate and non-condensable gas are obtained, the main component of the secondary condensate is a mixed liquid of hexachlorotrisiloxane, silicon tetrachloride and trichlorosilane, and the main component of the non-condensable gas is the main component hydrogen chloride gas; Secondary distillation: The condensate is again distilled into the distillation system 3 from the bottom liquid outlet of the final condensation system 4 for secondary distillation. The distillation temperature is set to 90°C and the pressure is set to 0.3MPa to obtain hexachlorotrisiloxane and mixed gas as secondary distillation products; Storage: The primary distillation product hexachlorotrisiloxane and the secondary distillation product hexachlorotrisiloxane enter the storage system.

[0024] The hexachlorotrisiloxane in the reaction product is fully separated by re-condensation and secondary distillation to obtain high-purity hexachlorotrisiloxane with a purity of 99.998%.

[0025] The mixed gas after the secondary distillation and the non-condensable gas after the re-condensation are discharged from the gas outlet at the top of the final condensation system 4 for recovery and treatment.

[0026] Embodiment 4: This embodiment provides a method for producing hexachlorotrisiloxane, comprising the following steps: Reaction: silicon tetrachloride and n-propanol are added into the reaction synthesizer 1 at a mass ratio of 38:18, the temperature in the reaction synthesizer 1 is set to 800°C, the pressure is set to 0.8MPa, and a reaction is carried out under the action of a catalyst boron Lewis acid to obtain a reaction product, the main components of which are hexachlorotrisiloxane, trichlorosilane, hydrogen chloride and unreacted raw material silicon tetrachloride gas; Primary condensation: The reaction product is drawn out from the top gas outlet of the reaction synthesizer 1 and enters the condensation system 2 for primary condensation. The outlet temperature of the process side of the condensation system is set to 50° C. and the pressure is 0.8 MPa to obtain primary condensate and non-condensable gas. The non-condensable gas is mainly hydrogen chloride and some hexachlorotrisiloxane that has not been completely condensed. Primary distillation: The primary condensate is drawn from the bottom liquid outlet of the condensation system 2 and enters the distillation system 3 for primary distillation. The distillation temperature is set to 95°C and the pressure is set to 0.35MPa to obtain hexachlorotrisiloxane and a mixed gas as the primary distillation product. The main components of the mixed gas are hexachlorotrisiloxane, silicon tetrachloride and trichlorosilane. Secondary condensation: the non-condensable gas obtained by the initial condensation enters the final condensation system 4 through the top gas outlet of the condensation system 2 for secondary condensation, and the mixed gas obtained after the primary distillation enters the final condensation system 4 through the top gas outlet of the distillation system 3 for secondary condensation, and the process side inlet temperature of the final condensation system 4 is 95° C., and the outlet temperature is 30° C.; secondary condensate and non-condensable gas are obtained, the main component of the secondary condensate is a mixed liquid of hexachlorotrisiloxane, silicon tetrachloride and trichlorosilane, and the main component of the non-condensable gas is the main component hydrogen chloride gas; Secondary distillation: The condensate is again distilled into the distillation system 3 from the bottom liquid outlet of the final condensation system 4 for secondary distillation. The distillation temperature is set to 95° C. and the pressure is set to 0.35 MPa to obtain hexachlorotrisiloxane and mixed gas as secondary distillation products; Storage: The primary distillation product hexachlorotrisiloxane and the secondary distillation product hexachlorotrisiloxane enter the storage system.

[0027] The hexachlorotrisiloxane in the reaction product is fully separated by re-condensation and secondary distillation to obtain high-purity hexachlorotrisiloxane with a purity of 99.992%.

[0028] The mixed gas after the secondary distillation and the non-condensable gas after the re-condensation are discharged from the gas outlet at the top of the final condensation system 4 for recovery and treatment.

[0029] like Figure 2-3 As shown, the hexachlorotrisiloxane obtained in Example 2-4 was qualitatively and quantitatively analyzed by using GC-MS (gas chromatography-mass spectrometry).

[0030] Figure 2 The chromatographic peak of hexachlorotrisiloxane is at 45.72 min.

[0031] Figure 3 It is the mass spectrum fragment peak of hexachlorotrisiloxane.

[0032] The hexachlorotrisiloxane product obtained in Example 2-4 was analyzed for metal impurities using an ICP-OES instrument to obtain the following Table 1: Table 1 Analysis results of the hexachlorotrisiloxane products obtained in Examples 2-4

[0033] In Table 1, OCTS represents the content of hexachlorotrisiloxane.

[0034] The purity of hexachlorotrisiloxane obtained under the conditions of the above-mentioned Examples 2 to 4 reached 99.99%.

[0035] Comparative Example 1: This example provides a method for producing hexachlorotrisiloxane. This comparative example is partially the same as Example 2, except that: The reaction temperature in the reaction synthesizer 1 is set to 500°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 hexachlorotrisiloxane is less, and the purity is 49.85%.

[0036] Comparative Example 2: This example provides a method for producing hexachlorotrisiloxane. This comparative example is partially the same as Example 3, except that: When the reaction temperature in the reaction synthesizer 1 is set to 380°C, the inhibitory effect of the catalyst on hydrogen free radicals is weakened, and hydrogen atoms are more likely to combine with oxygen atoms. The reduction of oxygen atoms leads to the generation of another substance - hexachlorodisiloxane, and its content is higher than that of hexachlorotrisiloxane. The purity of hexachlorotrisiloxane is 26.58%.

[0037] Comparative Example 3: This example provides a method for producing hexachlorotrisiloxane. This comparative example is partially the same as Example 4, except that: When the reaction temperature in the reaction synthesizer 1 is set to above 1000°C, the R group in the primary alcohol is more likely to combine with silicon to form an organic alkoxy substance, and the conversion rate of hexachlorotrisiloxane is reduced. When the temperature is higher than 1400°C, the catalyst is damaged and the reaction cannot proceed normally. The purity of the obtained hexachlorotrisiloxane is 53.47%.

[0038] Comparative Example 4: This example provides a method for producing hexachlorotrisiloxane. This comparative example is partially the same as Example 2, except that: The mass ratio of silicon tetrachloride and n-propanol was adjusted to 20:18. The raw materials did not react completely and the purity of hexachlorotrisiloxane could not meet the requirements. The purity of the obtained hexachlorotrisiloxane was 62.71%.

[0039] The purity of the hexachlorotrisiloxane products obtained through the processes of Examples 2-3 and Comparative Examples 1-4 is compared in Table 2 below: Table 2

[0040] By comparing the purity of hexachlorotrisiloxane obtained by Comparative Example 1, Comparative Example 2, Comparative Example 3, Comparative Example 4 with that of Example 2, Example 3, Example 4, it can be seen that when the raw materials silicon tetrachloride and primary alcohol react, the raw material mass ratio and the reaction temperature have a great influence on the reaction product, thereby having a great influence on the purity of the obtained hexachlorotrisiloxane.

[0041] 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 hexachlorotrisiloxane, characterized in that: The steps include: Reaction: silicon tetrachloride and primary alcohol are added into a reaction synthesizer in a mass ratio of 30-42:11-19, the reaction temperature is set to 650-800°C, the pressure is set to 0.6-0.8MPa, and a reaction is carried out under the action of a catalyst boron Lewis acid to obtain a reaction product; Primary condensation: The reaction product is subjected to primary condensation, and the outlet temperature of the process side of the condensation system is set to 40-50°C and the pressure is 0.6-0.8MPa to obtain primary condensate and non-condensable gas; Primary distillation: The primary condensate is subjected to primary distillation, the distillation temperature is set at 85-95°C, and the pressure is set at 0.25-0.35MPa to obtain primary distillation products of hexachlorotrisiloxane and mixed gas; Re-condensation: The non-condensable gas and mixed gas obtained by the initial condensation are re-condensed, and the inlet temperature of the process side of the final condensation system is 85~95℃, and the outlet temperature is 20~30℃; re-condensate and non-condensable gas are obtained; Secondary distillation: The condensate is subjected to secondary distillation, the distillation temperature is set to 85-95°C, and the pressure is set to 0.25-0.35MPa, to obtain secondary distillation products hexachlorotrisiloxane and mixed gas; Storage: The primary distillation product hexachlorotrisiloxane and the secondary distillation product hexachlorotrisiloxane enter the storage system.

2. The method for producing hexachlorotrisiloxane according to claim 1, characterized in that: The primary alcohol is a mixture of one or more of n-propanol, benzyl alcohol, isobutanol and n-butanol.

3. The method for producing hexachlorotrisiloxane according to claim 2, characterized in that: The mixed gas after secondary distillation and the non-condensable gas after re-condensation are discharged from the final condensation system and then recycled.

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