Production process for comprehensive utilization of methyl organosilicon low-boiling substance

Abstract

The present application relates to methyl organosilicon low boiling production technical field, especially to a kind of methyl organosilicon low boiling comprehensive utilization production process. Including the following steps: 1) in pressure reactor, add Lewis acid catalyst or Lewis acid further modified active catalyst, methyl organosilicon low boiling and methyl dichlorosilane, under certain temperature and pressure conditions, after a certain time, obtain trimethylchlorosilane reaction liquid;2) in the obtained trimethylchlorosilane reaction liquid, add complexing agent, remove catalyst;3) after removing catalyst, trimethylchlorosilane reaction liquid is rectified to obtain trimethylchlorosilane. The process can obtain the trimethylchlorosilane of higher economic value, solve the current methyl organosilicon low boiling comprehensive utilization low problem, also solve the monomer plant methyl dichlorosilane surplus problem.

Description

Technical Field

[0001] This invention belongs to the field of methyl organosilicon low-boiling-point product production technology, and particularly relates to a production process for the comprehensive utilization of methyl organosilicon low-boiling-point products. Background Technology

[0002] Methyl organosilicon low-boiling compounds refer to components with a boiling point below 40°C obtained from methyl organosilicon monomer synthesis. More specifically, they refer to components obtained by dimethylchlorosilane through distillation, in which the content of tetramethylsilane is about 30-70%, the content of dimethylchlorosilane is 5-20%, and the remainder consists of 2-methylbutane, 2-methyl-1-butene, 2-methyl-2-butene, etc.

[0003] Obtaining high-purity tetramethylsilane by processing low-boiling-point substances is currently a research hotspot. CN101955496A, CN108948063A, CN113214304A, and CN103539810B disclose research on converting chlorosilanes into hydrolysates with higher boiling points through hydrolysis. After removing chlorosilanes through hydrolysis, organic impurities are further removed by molecular sieve adsorption to obtain high-purity tetramethylsilane. However, due to the large impurity content, there is a problem of difficulty in industrial scale-up.

[0004] The disproportionation reaction of low-boiling-point compounds with other chlorosilane monomers to obtain new organosilicon monomers such as dimethyldichlorosilane and trimethylchlorosilane is also a current research hotspot. CN113831362A improves the yield of dimethyldichlorosilane and monomethyltrichlorosilane by directly catalytically reacting a mixture of organosilicon low-boiling-point compounds, monomethyltrichlorosilane, and trimethylchlorosilane on a catalyst-supported packing layer. The reaction process needs to be maintained at 87-89℃. CN118002043A mentions a production system for directly converting low-boiling-point compounds into trimethylchlorosilane. The low-boiling-point compounds described are tetramethylsilane, trichlorosilane, and dimethylchlorosilane, with contents of 50-70%, 5-20%, and 10-20%, respectively. The reaction temperature needs to reach 110-150℃, and the catalyst content of aluminum trichloride is 6-12% of the mixed mass. The reaction temperature is high and the catalyst addition is large. The untreated catalyst will undergo further disproportionation reaction in the subsequent distillation process.

[0005] How to utilize organosilicon to obtain high-value products with low waste, high efficiency, and green practices is a problem that organosilicon monomer manufacturers urgently need to solve. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a production process for the comprehensive utilization of low-boiling-point methyl organosilicon compounds. This process can obtain trimethylchlorosilane with high economic value, solves the problem of low comprehensive utilization of low-boiling-point methyl organosilicon compounds, and also solves the problem of excess methyl dichlorosilane in monomer plants.

[0007] To achieve the aforementioned objective, the technical solution of the present invention is implemented as follows: a production process for the comprehensive utilization of methyl organosilicon low-boiling-point compounds includes the following steps: 1) In a pressure reactor, a Lewis acid catalyst or an active catalyst further modified with Lewis acid, a methyl organosilicon low-boiling-point substance, and methyl dichlorosilane are added. After reacting for a certain time under certain temperature and pressure conditions, a trimethylchlorosilane reaction solution is obtained. 2) Add a complexing agent to the obtained trimethylchlorosilane reaction solution to remove the catalyst; 3) The trimethylchlorosilane reaction solution after removing the catalyst was distilled to obtain trimethylchlorosilane.

[0008] Furthermore, the pressure reactor is a high-pressure reactor, a tubular reactor, or a loop reactor combining a reactor and a tubular reactor. Furthermore, the Lewis acid catalyst is at least one of aluminum trichloride, ferric chloride, zinc chloride, or an active intermediate further modified from a Lewis acid catalyst; preferably, the catalyst is aluminum trichloride or an active intermediate modified from aluminum trichloride. The mass of the Lewis acid catalyst is 0.5-10 wt% of the total mass of the methyl organosilicon low-boiling-point compound and methyl dichlorosilane; preferably, the mass of the Lewis acid catalyst is 1-3 wt% of the total mass of the methyl organosilicon low-boiling-point compound and methyl dichlorosilane.

[0009] Furthermore, the methyldichlorosilane is a product obtained by fractionation of methyl organosilicon monomers, with a content (purity) of 90-99.99%.

[0010] Furthermore, the mass ratio of tetramethylsilane to methyldichlorosilane in the methyl organosilicon low-boiling compound is 1:0.3-1, more preferably 1:0.5-0.8.

[0011] Furthermore, in step 1), the reaction time is 2-10 hours, preferably 4-6 hours; the reaction temperature is 20-80°C, preferably room temperature (20°C) to 60°C, more preferably 35-45°C. Furthermore, the reaction pressure is the pressure generated by the reaction of the pressure reactor itself or the pressure reactor is pressurized to 0.1 MPa with nitrogen gas. Preferably, the reaction pressure is the pressure generated by the reaction of the pressure reactor itself.

[0012] Furthermore, the complexing agent is an amine hydrochloride, preferably one of ethylenediamine hydrochloride, ethylenediaminetetraacetic acid, methylamine hydrochloride, and triethylamine hydrochloride, and more preferably triethylamine hydrochloride.

[0013] Furthermore, the amount of the complexing agent added is 0.5-5 times the total mass of the Lewis acid catalyst; preferably, the amount of triethylamine hydrochloride added is 1-3 times the total mass of the Lewis acid catalyst.

[0014] Furthermore, in step 3), the trimethylchlorosilane reaction solution is subjected to atmospheric distillation or rectification to obtain a product with a purity ≥99%. Furthermore, in step 2), the content of metal ions such as Al and Fe in the reaction solution is reduced to 10-1000 ppm. Preferably, the content of metal ions in the reaction solution is reduced to 10-100 ppm after the addition of the complexing agent.

[0015] The beneficial effects of this invention are reflected in: This invention reacts low-boiling-point methyl organosilicon compounds with methyl dichlorosilane under Lewis acid catalyst conditions to obtain trimethylchlorosilane with high economic value. This solves the problem of low comprehensive utilization of low-boiling-point methyl organosilicon compounds and also solves the problem of excess methyl dichlorosilane in monomer plants. Moreover, the entire process is carried out at room temperature or slightly above room temperature, which is a green, low-carbon, and economically valuable method for the comprehensive utilization of low-boiling-point compounds. Attached Figure Description

[0016] Figure 1 Here are typical chromatograms of the reaction product components of this invention; Figure 2 This is a schematic diagram of the preparation process of Embodiment 3 of the present invention. Detailed Implementation

[0017] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] like Figure 1-2 As shown, the present invention provides a production process for the comprehensive utilization of methyl organosilicon low-boiling-point compounds.

[0019] Includes the following steps: 1) In a pressure reactor, a Lewis acid catalyst or an active catalyst further modified with Lewis acid, a methyl organosilicon low-boiling-point substance, and methyl dichlorosilane are added. After reacting for a certain time under certain temperature and pressure conditions, a trimethylchlorosilane reaction solution is obtained. 2) Add a complexing agent to the obtained trimethylchlorosilane reaction solution to remove the catalyst; 3) The trimethylchlorosilane reaction solution after removing the catalyst is subjected to atmospheric distillation or rectification to obtain trimethylchlorosilane.

[0020] Example 1 After purging with nitrogen, 500g of methyl organosilicon low-boiling-point compound, containing 66% tetramethylsilane, was added to a 1L high-pressure reactor. 320g of methyldichlorosilane and 5g of aluminum trichloride were also added. After reacting at room temperature (20℃) for 6 hours, the reaction pressure was 0.05Mpa. The vent valve was opened, and the tail gas was absorbed with water. 25g of triethylamine hydrochloride was then added to the mixture, and the mixture was separated to obtain the upper reaction liquid.

[0021] Chromatographic analysis revealed a trimethylchlorosilane content of 72.17%, with a calculated tetramethyl conversion rate of 88.86% and a methyldichlorosilane conversion rate of 91.37%. Elemental analysis of the reaction solution showed an aluminum content of 20 ppm.

[0022] Example 2 After purging with nitrogen, 114 kg of methyl organosilicon low-boiling-point compound (45% tetramethylsilane) was added to a 200 L high-pressure reactor. 51 kg of methyl dichlorosilane and 3 kg of aluminum trichloride were also added. After reacting at 40 °C for 4 h, the reaction pressure was 0.01 MPa. The vent valve was opened, and the tail gas was absorbed with water. Then, 4 kg of triethylamine hydrochloride was added to the mixture. The mixture was separated to obtain the upper reaction liquid.

[0023] Chromatographic analysis revealed a trimethylchlorosilane content of 71.63%, with a calculated tetramethyl conversion rate of 98.72% and a methyldichlorosilane conversion rate of 98.14%. Elemental analysis of the reaction solution showed an aluminum content of 78 ppm.

[0024] Example 3 This embodiment uses a loop reactor for production, and the process is shown in the attached diagram. Figure 2 As shown.

[0025] 1) A methyl organosilicon low-boiling-point compound (of which the content of tetramethylsilane is 45%) is pumped into stirred tank R1 at a rate of 125 kg / h, aluminum trichloride is pumped into stirred tank R1 at a rate of 7.5 kg / h, and methyl dichlorosilane is pumped into stirred tank R1 at a rate of 55 kg / h. The stirring speed of stirred tank R1 is controlled at 80 rpm / min. Stirred tank R1 is pumped into overflow tank V1 at a flow rate of 36 kg / h. No additional heating or pressurization is required in the whole process. The overflow tank overflows and the reaction solution flows into crude monomer tank V2.

[0026] 2) After adding 5000 kg of reaction liquid from crude monomer tank V2 to stirred tank R2, 200 kg of complexing agent triethylamine hydrochloride was added. After stirring and reacting for 4 hours, aluminum trichloride triethylamine hydrochloride complex was separated from the bottom. Chromatographic analysis of the upper reaction solution showed that the content of trimethylchlorosilane was 70.5% and the content of aluminum was 85 ppm.

[0027] 3) The reaction solution enters the atmospheric distillation system, and the components at 57.5℃ are collected to obtain 2600 kg of trimethylchlorosilane with a purity of 99%.

[0028] 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 principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A production process for the comprehensive utilization of low-boiling-point methyl organosilicon compounds, characterized in that, Includes the following steps: 1) In a pressure reactor, a Lewis acid catalyst or an active catalyst further modified with Lewis acid, a methyl organosilicon low-boiling-point substance, and methyl dichlorosilane are added. After reacting for a certain time under certain temperature and pressure conditions, a trimethylchlorosilane reaction solution is obtained. 2) After adding a complexing agent to the obtained trimethylchlorosilane reaction solution, a Lewis acid complex is formed, and the catalyst is removed by liquid-liquid separation. 3) Trimethylchlorosilane is obtained by distillation or atmospheric distillation of the reaction solution after removing the catalyst.

2. The production process for comprehensive utilization of methyl organosilicon low-boiling-point compounds according to claim 1, characterized in that, In step 1), the Lewis acid catalyst is at least one of aluminum trichloride, ferric trichloride, zinc chloride, or an active intermediate further modified from the Lewis acid catalyst; and the mass of the Lewis acid catalyst is 0.5-10 wt% of the total mass of the methyl organosilicon low-boiling product and methyl dichlorosilane.

3. The production process for comprehensive utilization of methyl organosilicon low-boiling-point compounds according to claim 1, characterized in that, In step 1), the methyl organosilicon low-boiling product is a low-boiling product fractionated from the methyl organosilicon monomer after further distillation, wherein the content of tetramethylsilane is 45-66%.

4. A production process for the comprehensive utilization of methyl organosilicon low-boiling-point compounds according to claim 1, 2, or 3, characterized in that, In step 1), the methyldichlorosilane is a product obtained by fractionation of methyl organosilicon monomers, with a content of 90-99.99%.

5. The production process for comprehensive utilization of methyl organosilicon low-boiling-point compounds according to claim 3, characterized in that, In step 1), the mass ratio of tetramethylsilane to methyldichlorosilane in the methyl organosilicon low-boiling compound is 1:0.3-1.

6. The production process for comprehensive utilization of methyl organosilicon low-boiling-point compounds according to claim 1, characterized in that, In step 1), the reaction time is 4-6 hours and the reaction temperature is 20-40°C.

7. The production process for comprehensive utilization of methyl organosilicon low-boiling-point compounds according to claim 4, characterized in that, In step 1), the reaction pressure is the pressure generated by the reaction of the pressure reactor itself or the pressure reactor is pressurized to 0.1 MPa with nitrogen.

8. The production process for comprehensive utilization of methyl organosilicon low-boiling-point compounds according to claim 4, characterized in that, In step 2), the complexing reagent is an amine hydrochloride; the amine hydrochloride is one of ethylenediamine hydrochloride, ethylenediaminetetraacetic acid, methylamine hydrochloride, and triethylamine hydrochloride.

9. A production process for the comprehensive utilization of methyl organosilicon low-boiling-point compounds according to claim 1 or 8, characterized in that, In step 2), the amount of the complexing reagent added is 0.5-5 times the total mass of the Lewis acid catalyst.

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