Method for synthesizing tris (trimethylsilane) borate through microchannel reactor
The synthesis of tris(trimethylsilane)boronic acid esters via a microchannel reactor solves the problems of long reaction time, low yield, and high cost due to catalyst use in existing technologies, achieving efficient, safe, and low-cost industrial production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANDONG FURUWEI TECHNOLOGY CO LTD
- Filing Date
- 2026-02-09
- Publication Date
- 2026-05-19
AI Technical Summary
Existing methods for synthesizing tris(trimethylsilane)borate esters have long reaction times and low yields. The use of catalysts increases production costs and makes waste disposal more difficult, making it hard to achieve industrial-scale production.
A method for synthesizing tris(trimethylsilane)boronic acid esters using a microchannel reactor involves reacting boric acid and hexamethyldisilazane in the microchannel reactor, using a solvent to dissolve the raw materials, and carrying out the reaction under set temperature, pressure, and residence time. The post-processing is simple and avoids the use of catalysts.
It significantly shortens reaction time, improves production efficiency, reduces side reactions, lowers production costs, increases product yield and purity, simplifies post-processing, and enables environmentally friendly continuous production.
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Figure CN122059979A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of lithium battery electrolyte additive technology, specifically relating to a method for synthesizing tris(trimethylsilane)boronic acid esters using a microchannel reactor. Background Technology
[0002] Electrolyte additives are functional substances added in minute quantities (0.1%–5% of the total electrolyte mass) to selectively optimize battery performance. The presence of additives significantly improves the electrochemical performance of the electrolyte and the quality of cathode deposition. Existing additives are generally one or more natural or synthetic compounds. When selecting additives, it is essential to ensure that they do not participate in the electrode reactions during the electrolysis process and can significantly improve the electrochemical performance of the electrolyte. Their main functions include forming a solid electrolyte interphase (SEI) film on the electrode surface, suppressing side reactions, protecting the electrode structure, and improving cycle life; and enhancing the electrolyte conductivity and thermal stability by adjusting the ion-solubilized structure, adapting to extreme operating conditions such as high voltage and low temperature.
[0003] Tris(trimethylsilane)borate is a boron-containing organosilicon compound that can be used as a film-forming additive in lithium-ion battery electrolytes. It helps form a protective solid electrolyte interface film, significantly improving the high-temperature storage and performance of the electrolyte system in lithium-ion batteries. This not only significantly extends battery life but also effectively suppresses side reactions in gel polymer batteries. Therefore, it has wide applications in lithium iron phosphate, lithium manganese oxide, and lithium titanate lithium-ion batteries.
[0004] The main synthetic routes for tris(trimethylsilane)borate esters reported to date are as follows: Initially, MG Voronkov's research team prepared tris(trimethylsilane)borate by reacting boron trioxide with hexamethyldisiloxane in a pressure vessel at 350°C for 27 h, with a yield of only 13.3%. Subsequently, they refluxed trimethylchlorosilane with boric acid for 15 h, achieving a crude product yield of 26.4%; and then heated the reaction under tetrahydrofuran catalysis for 24 h, with a yield of only 22%. Both of these synthetic routes had long reaction times and low yields, only 10-26%, making industrial-scale production impossible.
[0005] Korean invention patent KR20100090152[P] discloses a method for synthesizing tris(trimethylsilane)boronic acid ester by reacting hexamethyldisilazane with boric acid at 70~85℃ and 110~120℃ for 10h, which successfully increased the yield to 71.4%.
[0006] Chinese invention patent CN201310268325.3 discloses another method for preparing high-purity trisilylated borate esters, which involves reacting hexamethyldisilazane and boric acid for 3 hours under organic ammonia catalysis to synthesize trisilylated borate esters, increasing the yield to 83%. However, this method introduces a non-recyclable organic ammonia catalyst, with the catalyst feed amount being 5-50% of the boric acid mass, increasing the amount of waste generated and the difficulty of treatment.
[0007] Chinese invention patent CN201410099946.8 reports a method for synthesizing tris(trimethylsilane)boronic acid ester by reacting hexamethyldisilazane with boric acid under reaction conditions of 60-80℃ using sulfonic acid-type resin catalysis, with a yield of 85% after 1-3 hours of reaction. However, this method requires the use of a resin catalyst and pre-activation treatment, and the subsequent separation and reuse of the catalyst is difficult, increasing the amount of waste generated and the cost.
[0008] Subsequently, MG Voronkov's research team further optimized the experimental conditions using hexamethyldisilazane and boric acid. Under the catalysis of a small amount of quaternary ammonium salt, the reaction was carried out at 115°C for 10 hours. The crude product was distilled and the purity reached 99.95%, with a yield of 86%.
[0009] These methods involve reaction times of 10 hours or more, resulting in low production efficiency. While using catalysts shortens the reaction time and increases the yield to 86%, the addition of large amounts of catalysts increases production and solid waste treatment costs.
[0010] The above methods for synthesizing tris(trimethylsilane)boronic acid esters have several main problems: First, the initial reaction routes have low yields, making industrial production impossible; second, the long reaction times significantly reduce production efficiency, hindering efficient, rapid, and stable production; and third, the use of catalysts requires initial activation, and subsequent separation and reuse are difficult, increasing waste generation and treatment complexity, resulting in higher production costs and limiting the progress of industrialization. Summary of the Invention
[0011] This invention provides a method for synthesizing tris(trimethylsilane)boronic acid esters using a microchannel reactor. The method uses boric acid and hexamethyldisilazane as raw materials and reacts them in a microchannel reactor. The raw materials are relatively safe, the reaction efficiency is high, the byproducts are environmentally friendly and have low corrosiveness to equipment, the post-processing is simple, the product yield is high, and no catalyst is involved, which reduces the waste treatment process and saves production costs.
[0012] The technical solution of this invention is as follows: A method for synthesizing tris(trimethylsilane)boronic acid esters using a microchannel reactor includes the following steps: 1) Raw material preparation: Dissolve the reactants boric acid and hexamethyldisilazane in solvents to prepare boric acid solution and hexamethyldisilazane solution respectively; 2) Microchannel reaction: The prepared boric acid solution and hexamethyldisilazane solution are delivered to the microchannel reactor and reacted at the set reaction temperature, reaction pressure and residence time to obtain the reaction solution; 3) Product separation: The reaction solution was distilled under reduced pressure to obtain the product tris(trimethylsilane)boronic acid ester.
[0013] Preferably, the solvent is one or more of the following solvents: 1,2-dichloroethane, acetonitrile, toluene, tetrahydrofuran, dimethyl carbonate, diethyl carbonate, and methyl ethyl carbonate.
[0014] Preferably, the concentration of the boric acid solution in step 1) is 0.05~1 mol / L, and the concentration of the hexamethyldisilazane solution is 0.05~3 mol / L.
[0015] Preferably, the flow rate of the boric acid solution in step 2) is 5.0~10 mL / min, and the flow rate of the hexamethyldisilazane solution is 5.0~10 mL / min.
[0016] Preferably, the reaction temperature is 75~120℃, the reaction pressure is 0~3MPa, and the residence time is 30s~100s.
[0017] This invention provides a method for the continuous synthesis of tris(trimethylsilane)boronic acid esters using a microchannel reactor. The method involves reacting anhydrous boric acid and hexamethyldisilazane dissolved in a solvent as raw materials under heating conditions in a microchannel reactor. After post-treatment, tris(trimethylsilane)boronic acid esters are obtained. The reaction formula is shown below: ; The feed ratio is precisely controlled, and the reactor has high mass and heat transfer efficiency. It can complete the full mixing and reaction process instantly upon material contact, effectively suppressing side reactions caused by excessively high local concentrations of single raw materials or intermediate states. The reaction process can be completed within a few seconds to tens of seconds, significantly shortening the reaction time and greatly improving production efficiency compared to batch reaction processes. The microchannel reactor's channel structure enables thorough mixing of reactants, achieving complete reaction even without catalyst addition. This simplifies post-processing, reduces waste generation, saves raw material costs, and improves overall profitability. Continuous synthesis of tris(trimethylsilane)boronic esters using microchannel reactors results in low online liquid hold-up, minimizing the risk of reaction runaway and ensuring inherent safety. Furthermore, it automates the entire process from feeding to discharging and reaction quenching, enabling unmanned operation and significantly enhancing automation levels for rapid industrial-scale production.
[0018] Microchannel reactors, with their numerous microchannels, offer high mass and heat transfer efficiency, enabling instantaneous and uniform mixing of materials and efficient heat transfer. In a microchannel reactor, two fluids diverge and then converge through the microchannels. Due to the small width and depth of the microchannels, the fluid diffusion distance between reactors is significantly shortened, resulting in rapid mass transfer and thorough mixing of reactants within a short time. Microchannel reactors enhance mass and heat transfer processes, precisely control reaction conditions, and improve reaction efficiency. They also feature low online liquid holdup, inherent safety, small reactor size, and low equipment investment, making them an environmentally friendly and highly efficient production device.
[0019] Compared with the prior art, the present invention has the following advantages: 1. The present invention has a short reaction time: the microchannel reactor has extremely high mass and heat transfer efficiency, which can significantly shorten the reaction time. The conventional synthesis of tris(trimethylsilane)borate ester generally takes several hours or even more than ten hours, while the synthesis in the microchannel reactor can be completed in a few seconds to tens of seconds, which significantly improves the production efficiency. Moreover, the reaction is carried out without the addition of an additional catalyst.
[0020] 2. Low cost and high yield: The fluid flow state in the microchannel reactor is controllable, which can effectively suppress the occurrence of side reactions, such as the side reaction of ammonia and boric acid, improve the yield of the target product, reduce the addition of catalyst, simplify the production operation steps, and save production costs.
[0021] 3. High product purity: The reaction conditions in the microchannel reactor are uniform, resulting in high product purity. It is easy to separate and purify the product, with a purity of up to 99.93%. No catalyst is required, which reduces the generation of solid waste at the source.
[0022] 4. High safety: Microchannel reactors have a small liquid holding capacity, which can effectively control reaction risks and improve production safety.
[0023] 5. Easy to achieve continuous production: Microchannel reactors are easy to operate continuously, which is conducive to improving production efficiency and automation level. Attached Figure Description
[0024] Figure 1 This is a schematic flowchart of the preparation method of the present invention.
[0025] Figure 2 This is a schematic diagram of the microchannel reactor of the present invention.
[0026] Figure 3 This is the gas chromatogram of the third batch of products in Example 3 of the present invention.
[0027] In the diagram, 1 is the first feed inlet; 2 is the second feed inlet; 3 is the discharge outlet; 4 is the mixing unit; 5 is the first reaction channel; 6 is the second reaction channel; 7 is the first pipeline; 8 is the sub-channel; 9 is the "V"-shaped flow divider structure; 10 is the flow bypass area; and 11 is the blocking protrusion. Detailed Implementation
[0028] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions will be clearly and completely described below in conjunction with the embodiments of this invention.
[0029] like Figure 2 As shown, the specific structure of the microchannel reactor used in the embodiments and comparative examples is as follows: The microchannel reactor is provided with a first inlet 1 (hexamethyldisilazane), a second inlet 2 (boric acid feed), an outlet 3 and a mixing unit 4. Both the first inlet 1 and the second inlet 2 are provided with flow pumps, which are electrically connected to the controller. The outlet 3 is provided with a back pressure valve, which is electrically connected to the controller. Both the first feed inlet 1 and the second feed inlet 2 are connected to the mixing unit 4. Several mixing units 4 are interconnected to form a reaction channel 1 5. The outlet of the reaction channel 1 5 is connected to several reaction channels 2 6 in sequence through pipelines. Each reaction channel 2 6 includes two sets of several mixing units 4 arranged in parallel in the horizontal direction. The vertically corresponding mixing units 4 in the two sets of parallel mixing units 4 are connected through pipeline 1 7. Several blocking protrusions 11 are provided in the pipelines connecting the reaction channel 1 5 and the reaction channel 2 6, as well as in the pipelines connecting two adjacent reaction channels 2 6. The last reaction channel 2 6 is connected to the discharge port 3.
[0030] Two adjacent mixing units 4 are connected by a sub-channel 8. Each mixing unit 4 is equipped with a "human"-shaped flow splitting structure 9 and a flow bypass zone 10.
[0031] The "human" shaped diversion structure 9 is a centrally symmetrical structure. The width of the "human" shaped diversion structure 9 is half the width of the sub-channel 8. It should be noted that the width of the "human" shaped diversion structure 9 is the thickness of each side of the "human" shape.
[0032] The flow-around region 10 is cylindrical, and the diameter of the flow-around region 10 is the same as the width of the sub-channel 8.
[0033] Example 1 The method for synthesizing tris(trimethylsilane)boronic acid esters using the microchannel reactor includes the following steps: 1) Raw material preparation: Dissolve the reactant boric acid in acetonitrile to prepare an acetonitrile solution with a concentration of 0.5 mol / L boric acid; dissolve hexamethyldisilazane in acetonitrile to prepare an acetonitrile solution with a concentration of 0.5 mol / L hexamethyldisilazane; 2) Microchannel reaction: A boric acid acetonitrile solution and a hexamethyldisilazane acetonitrile solution were introduced into a microchannel reactor at a flow rate of 8 mL / min and a molar ratio of boric acid to hexamethyldisilazane of 1:1. The reaction temperature was controlled at 75℃, the reaction pressure at 0.5 MPa, and the residence time at 50 s. After the reaction was completed, the reaction solution flowed out of the reactor outlet and entered the post-processing process. 3) Product separation: The reaction solution was distilled under reduced pressure to obtain the product tris(trimethylsilane)boronic acid ester.
[0034] Three batches of trial production were carried out under the reaction conditions, and the results are shown in Table 1.
[0035] Table 1 Production Results of Example 1
[0036] Example 2 The method for synthesizing tris(trimethylsilane)boronic acid esters using the microchannel reactor includes the following steps: 1) Raw material preparation: Dissolve the reactant boric acid in acetonitrile to prepare an acetonitrile solution with a concentration of 0.5 mol / L boric acid; dissolve hexamethyldisilazane in acetonitrile to prepare an acetonitrile solution with a concentration of 0.5 mol / L hexamethyldisilazane; 2) Microchannel reaction: The acetonitrile solution of boric acid and the acetonitrile solution of hexamethyldisilazane were introduced into a microchannel reactor at a flow rate of 8 mL / min and a flow rate of 8 mL / min, respectively, with a molar ratio of boric acid to hexamethyldisilazane of 1:1. The reaction temperature was controlled at 85℃, the reaction pressure at 1.0 MPa, and the residence time at 80 s. After the reaction was completed, the reaction solution flowed out of the reactor outlet and entered the post-processing process. 3) Product separation: The reaction solution was distilled under reduced pressure to obtain the product tris(trimethylsilane)boronic acid ester.
[0037] Three batches of trial production were carried out under the reaction conditions, and the results are shown in Table 2.
[0038] Table 2 Production Results of Example 2
[0039] Example 3 The method for synthesizing tris(trimethylsilane)boronic acid esters using the microchannel reactor includes the following steps: 1) Raw material preparation: Dissolve the reactant boric acid in acetonitrile to prepare an acetonitrile solution with a concentration of 0.5 mol / L boric acid; dissolve hexamethyldisilazane in acetonitrile to prepare an acetonitrile solution with a concentration of 0.5 mol / L hexamethyldisilazane; 2) Microchannel reaction: The acetonitrile solution of boric acid was introduced into a microchannel reactor at a flow rate of 8 mL / min and the acetonitrile solution of hexamethyldisilazane was introduced at a flow rate of 10 mL / min, with the molar ratio of boric acid to hexamethyldisilazane being 1:1.2. The reaction temperature was controlled at 115℃, the reaction pressure at 2.0 MPa, and the residence time at 60 s. After the reaction was completed, the reaction solution flowed out of the reactor outlet and entered the post-processing process. 3) Product separation: The reaction solution was distilled under reduced pressure to obtain the product tris(trimethylsilane)boronic acid ester.
[0040] Three batches of trial production were carried out under the reaction conditions, and the results are shown in Table 3.
[0041] Table 3 Production Results of Example 3
[0042] The products from the third batch of experiments in Example 3 were subjected to gas chromatography analysis, as detailed below: An Agilent gas chromatograph detector and a DB-35 capillary column were used. The vaporization chamber temperature was 270°C, the detector temperature was 280°C, the column temperature was 80°C for 2 min, then increased to 260°C at a rate of 20°C / min and held for 10 min. Gas chromatography was performed on the sample. The results are as follows: Figure 3 As shown, the peak with a retention time of 3.535 min is the unreacted raw material hexamethyldisilazane, accounting for 0.16%, and the peak with a retention time of 6.410 min is tris(trimethylsilane)boronic acid ester, accounting for 99.84%.
[0043] Example 4 Unlike Example 3, the concentrations of the acetonitrile solution of boric acid and the acetonitrile solution of hexamethyldisilazane in this example are both 0.3 mol / L. The remaining preparation methods and steps are the same as in Example 3. Three batches were produced, with an average purity of 99.9% and an average yield of 92.7%.
[0044] Comparative Example 1 In this comparative example, tris(trimethylsilane)boronic acid esters were prepared using conventional methods, as detailed below: In a 500 mL three-necked flask, 30.9 g (0.5 mol) boric acid, 80.70 g (0.5 mol) hexamethyldisilazane, and 300 mL dimethyl carbonate were added. The mixture was stirred and refluxed at 90 °C for 8 h. After the reaction was completed, the organic phase was concentrated and then distilled under reduced pressure to obtain the product tris(trimethylsilane)boronic acid ester, with a total yield of 65% and a purity of 96.7%.
[0045] Comparative Example 2 Based on Example 1, 1% by weight of tetrabutylammonium bromide, a phase transfer catalyst, was added to the acetonitrile solution of hexamethyldisilazane. The final product yield was 78% and the purity was 98.5%. Compared with Example 1, this comparative example added a catalyst, and the yield and purity of the final product were comparable to those of Example 1. This proves that the solution of the present invention can achieve the same mixing effect without the addition of an additional catalyst, thus saving costs and reducing post-processing steps.
[0046] Although the present invention has been described in detail by way of preferred embodiments, the invention is not limited thereto. Various equivalent modifications or substitutions can be made to the embodiments of the present invention by those skilled in the art without departing from the spirit and essence of the invention, and such modifications or substitutions should all be within the scope of the invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.
Claims
1. A method for synthesizing tris(trimethylsilane)borate esters using a microchannel reactor, characterized in that, Includes the following steps: 1) Raw material preparation: Dissolve the reactants boric acid and hexamethyldisilazane in solvents to prepare boric acid solution and hexamethyldisilazane solution respectively; 2) Microchannel reaction: The prepared boric acid solution and hexamethyldisilazane solution are delivered to the microchannel reactor and reacted at the set reaction temperature, reaction pressure and residence time to obtain the reaction solution; 3) Product separation: The reaction solution was distilled under reduced pressure to obtain the product tris(trimethylsilane)boronic acid ester.
2. The method for synthesizing tris(trimethylsilane)boronic acid esters using a microchannel reactor as described in claim 1, characterized in that, The solvent is one or more of the following solvents: 1,2-dichloroethane, acetonitrile, toluene, tetrahydrofuran, dimethyl carbonate, diethyl carbonate, and methyl ethyl carbonate.
3. The method for synthesizing tris(trimethylsilane)boronic acid esters using a microchannel reactor as described in claim 1, characterized in that, The concentration of the boric acid solution in step 1) is 0.05~1 mol / L, and the concentration of the hexamethyldisilazane solution is 0.05~3 mol / L.
4. The method for synthesizing tris(trimethylsilane)boronic acid esters using a microchannel reactor as described in claim 1, characterized in that, The flow rate of the boric acid solution in step 2) is 5.0~10 mL / min, and the flow rate of the hexamethyldisilazane solution is 5.0~10 mL / min.
5. The method for synthesizing tris(trimethylsilane)boronic acid esters using a microchannel reactor as described in claim 1, characterized in that, The reaction temperature is 75~120℃, the reaction pressure is 0~3MPa, and the residence time is 30s~100s.