Preparation method of pentafluorophenyltriethoxysilane
By using a grid reaction with magnesium shavings and a zeolite packing layer in a fixed-bed reactor, high-purity pentafluorophenyltriethoxysilane was prepared, solving the problems of low purity and high cost in existing technologies and achieving efficient and low-cost production.
Patent Information
- Application Number
- CN202411145921.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-20
- Publication Date
- 2026-03-03
AI Technical Summary
The existing pentafluorophenyltriethoxysilane has low purity and is expensive, so there is a need to develop a preparation method with higher purity and lower cost.
Using bromopentafluorobenzene and tetraethyl orthosilicate as raw materials, a Grignard reaction was carried out in a fixed-bed reactor with magnesium shavings and zeolite packing. Iodine particles were used as initiators, and the reaction was carried out in a mixed solvent of anhydrous tetrahydrofuran and benzene. The reaction temperature and time were optimized to reduce the formation of by-products.
High-purity (over 97.0%) pentafluorophenyltriethoxysilane was prepared, reducing production costs. The reaction yield was improved by extending the reaction time and contact area, while reducing energy consumption and byproduct generation.
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Figure CN121591774A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of battery electrolyte technology, and relates to a method for preparing electrolyte additives, particularly a method for preparing pentafluorophenyltriethoxysilane. Background Technology
[0002] Electrolyte additives are small amounts of substances added to the electrolyte to improve its electrochemical performance and enhance cathode deposition quality. While they generally do not participate in the electrode reactions of the electrolysis process, they can improve the electrochemical performance of the electrolyte system, influence ion discharge conditions, and optimize the electrolysis process, making them an indispensable part of the electrolyte system.
[0003] Pentafluorophenyltriethoxysilane is a commonly used chemical reagent. When used as an electrolyte additive, it can be oxidized and decomposed before other materials in the electrolyte under high voltage, forming a stable solid CEI film. This inhibits electrolyte decomposition and slows down the dissolution, migration, and precipitation of transition metal ions. Furthermore, the fluorine atoms in this substance can enhance the ionic conductivity of the CEI film. Therefore, pentafluorophenyltriethoxysilane is an excellent electrolyte additive.
[0004] However, currently available pentafluorophenyltriethoxysilanes only achieve a purity of 95% and are expensive, costing over 350 yuan per gram. Therefore, research is needed on the preparation methods of pentafluorophenyltriethoxysilanes to produce products with higher purity and lower production costs. Summary of the Invention
[0005] The purpose of this invention is to reduce the overall production cost of pentafluorophenyltriethoxysilane and to prepare a high-purity product. This invention studies the preparation method of pentafluorophenyltriethoxysilane, and optimizes the reaction mode, reduces the reaction temperature and reduces the generation of by-products.
[0006] The technical solution adopted in this invention is a method for preparing pentafluorophenyltriethoxysilane. The key point is that the above preparation method uses bromopentafluorobenzene and tetraethyl orthosilicate as raw materials, and a Grignard reaction is carried out under the action of a catalyst to generate pentafluorophenyltriethoxysilane. After vacuum distillation, the pentafluorophenyltriethoxysilane product is obtained. The catalyst is magnesium shavings, and the Grignard reaction is carried out in an anhydrous organic solvent with iodine particles as the initiator. The molar ratio of magnesium shavings, bromopentafluorobenzene, tetraethyl orthosilicate and iodine particles is 1:0.8~1.2:0.8~1.2:0.0005~0.001.
[0007] Specifically, the aforementioned anhydrous organic solvent is anhydrous tetrahydrofuran or a mixture of anhydrous tetrahydrofuran and benzene.
[0008] More specifically, in the above-mentioned mixed solvent of anhydrous tetrahydrofuran and benzene, the volume ratio of tetrahydrofuran to benzene is 2 to 4:1.
[0009] Preferably, the reaction temperature is 30℃~40℃ and the reaction time is 4h~8h.
[0010] Furthermore, the specific reaction steps are as follows:
[0011] S1. Soak the zeolite in the soaking solution, remove it, drain it, and set it aside;
[0012] S2. Inert gas is introduced into the fixed-bed reactor, magnesium shavings and iodine granules are mixed, and soaked zeolite is added to form a packing layer.
[0013] S4. Mix pentafluorobenzene with tetrahydrofuran to obtain a mixed solution. Slowly feed the mixed solution from the bottom to the top of the fixed bed reactor until it is discharged from the top. Circulate the mixed solution for 4 to 6 hours to obtain a tetrahydrofuran solution of pentafluorophenyl magnesium bromide.
[0014] S5. Add tetraethyl orthosilicate to the reaction vessel, and add the tetrahydrofuran solution of the aforementioned pentafluorophenyl magnesium bromide dropwise. After the addition is complete, heat and stir the reaction. After the reaction is completed, distill under reduced pressure to obtain the pentafluorophenyltriethoxysilane product.
[0015] Preferably, the particle size ratio of the magnesium shavings to the zeolite is 1:1.2 to 2.0, and the particle size of the magnesium shavings is 1.0 mm to 2.0 mm.
[0016] Specifically, the soaking time for the zeolite is 0.5h to 1h.
[0017] More specifically, the zeolite mentioned above is a synthetic zeolite, composed of sulfonated polystyrene, and can be recycled and reused.
[0018] Preferably, the soaking solution is any one of iodomethane, iodoethane, and bromobenzene.
[0019] Compared with the prior art, the present invention has the following advantages:
[0020] This invention uses pentafluorobenzene and tetraethyl orthosilicate as raw materials to prepare pentafluorophenyltriethoxysilane via Grignard reaction. In the preparation of the Grignard reagent, this invention uses magnesium shavings and zeolite as the packing layer in a fixed-bed reactor, extending the material contact time and contact area, and significantly shortening the reaction time. Furthermore, the zeolite used in this invention is soaked in solutions such as periodomethane, which not only eliminates the influence of oxygen inside the zeolite on the reaction, but also allows the solution adsorbed by the zeolite to co-initiate the reaction with the iodine particles, reducing the amount of iodine particles required.
[0021] This invention uses a zeolite and magnesium shavings filler layer and specifies the particle size ratio of magnesium shavings to zeolite to avoid using excessively fine magnesium powder. The magnesium shavings used in this invention have a suitable particle size, are not easily oxidized during use, do not clog the reaction channels of the zeolite, are easier to recover, and residual magnesium shavings can be used in the next production. Residual Grignard reagents and other materials in the zeolite can be used in the next reaction without further soaking or adding initiator, and the reaction yield and the purity of the obtained product do not change significantly.
[0022] This invention discovers that using a mixed solvent of tetrahydrofuran and benzene does not affect the reaction. It is well known that the Grignard reaction commonly uses tetrahydrofuran or diethyl ether as solvents. Since tetrahydrofuran has a higher boiling point than diethyl ether, the safer tetrahydrofuran is generally chosen as the solvent. However, this invention finds that mixing a portion of benzene into tetrahydrofuran allows the Grignard reaction to proceed smoothly. Benzene has a higher boiling point than tetrahydrofuran and is also cheaper, thus helping to reduce production costs. Attached Figure Description
[0023] Figure 1 This is the high-performance gas phase spectrum of sample 1 prepared in this invention. Detailed Implementation
[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0025] Unless otherwise specified in the examples, the procedures can be followed according to conventional conditions; unless the manufacturers of the reagents or instruments used are specified, they are all conventional products that can be purchased commercially.
[0026] For ease of description, the following is in parts by weight.
[0027] Example 1
[0028] S1. Soak the artificial zeolite in iodomethane for 40 minutes, until the iodomethane completely submerges the artificial zeolite. Remove the artificial zeolite, let it drain naturally, and set aside.
[0029] S2. Nitrogen gas is introduced into the fixed bed reactor. 24.3 parts magnesium shavings and 0.20 parts iodine granules are mixed, and 100 parts soaked artificial zeolite are added to the mixture. The materials are mixed evenly to form a packing layer. In this embodiment, the molar ratio of magnesium shavings to iodine granules is 1:0.0008. The average particle size of the magnesium shavings used in this embodiment is 1.25 mm, and the average particle size of the artificial zeolite used is 1.95 mm.
[0030] The test method for the average particle size of magnesium shavings and artificial zeolite is as follows: randomly select the sample to be tested, determine its maximum particle size, test each sample 3 times, and take the arithmetic mean as the test result of this sampling; perform 6 random samplings for each material and calculate the arithmetic mean.
[0031] S4. Mix 220 parts of bromopentafluorobenzene with 1760 parts of dry tetrahydrofuran to obtain a mixture. Slowly feed the mixture from the bottom to the top of the fixed bed reactor until it is discharged from the top. Circulate for 5 hours to obtain a tetrahydrofuran solution of pentafluorophenyl magnesium bromide.
[0032] S5. Add 240 parts of tetraethyl orthosilicate to the reaction vessel, and slowly add the prepared tetrahydrofuran solution of pentafluorophenyl magnesium bromide. After the addition is complete, raise the temperature to 35°C, stir and keep the reaction at this temperature for 6 hours. After the reaction is completed, distill under reduced pressure to obtain pentafluorophenyltriethoxysilane sample 1.
[0033] Example 2
[0034] S1. Soak the artificial zeolite in iodoethane for 30 minutes, until the iodoethane completely submerges the artificial zeolite. Remove the artificial zeolite and let it drain naturally from the solvent. Set aside for later use.
[0035] S2. Nitrogen gas is introduced into the fixed bed reactor. 24.3 parts magnesium shavings and 0.13 parts iodine granules are mixed, and 80 parts soaked artificial zeolite are added to the mixture. The materials are mixed evenly to form a packing layer. In this embodiment, the molar ratio of magnesium shavings to iodine granules is 1:0.0005. The average particle size of the magnesium shavings used in this embodiment is 1.01 mm, and the average particle size of the artificial zeolite used is 1.99 mm.
[0036] The method for testing the average particle size of magnesium shavings and synthetic zeolite is the same as in Example 1;
[0037] S4. Mix 198 parts of bromopentafluorobenzene with 1485 parts of dry tetrahydrofuran mixed solvent (the volume ratio of tetrahydrofuran to benzene is 4:1) to obtain a mixed solution. Slowly feed the mixed solution from the bottom to the top of the fixed bed reactor until it is discharged from the top. Circulate for 4 hours to obtain a tetrahydrofuran solution of pentafluorophenyl magnesium bromide.
[0038] S5. Add 210 parts of tetraethyl orthosilicate to the reaction vessel, and slowly add the prepared tetrahydrofuran solution of pentafluorophenyl magnesium bromide. After the addition is complete, raise the temperature to 30°C, stir and keep the reaction at this temperature for 8 hours. After the reaction is completed, distill under reduced pressure to obtain pentafluorophenyltriethoxysilane sample 2.
[0039] Example 3
[0040] S1. Soak the artificial zeolite in bromobenzene for 60 minutes, until the bromobenzene completely submerges the artificial zeolite. Remove the artificial zeolite, let it drain naturally, and set aside.
[0041] S2. Nitrogen gas is introduced into the fixed bed reactor. 24.3 parts magnesium shavings and 0.25 parts iodine granules are mixed, and 120 parts soaked artificial zeolite are added to the mixture. The materials are mixed evenly to form a packing layer. In this embodiment, the molar ratio of magnesium shavings to iodine granules is 1:0.001. The average particle size of the magnesium shavings used in this embodiment is 1.65 mm, and the average particle size of the artificial zeolite used is 1.99 mm.
[0042] The method for testing the average particle size of magnesium shavings and synthetic zeolite is the same as in Example 1;
[0043] S4. Mix 247 parts of bromopentafluorobenzene with 1482 parts of dry tetrahydrofuran mixed solvent (the volume ratio of tetrahydrofuran to benzene is 2:1) to obtain a mixed solution. Slowly feed the mixed solution from the bottom to the top of the fixed bed reactor until it is discharged from the top. Circulate for 6 hours to obtain a tetrahydrofuran solution of pentafluorophenyl magnesium bromide.
[0044] S5. Add 264 parts of tetraethyl orthosilicate to the reaction vessel, and slowly add the prepared tetrahydrofuran solution of pentafluorophenyl magnesium bromide. After the addition is complete, raise the temperature to 40°C, stir and keep the reaction at this temperature for 4 hours. After the reaction is completed, distill under reduced pressure to obtain pentafluorophenyltriethoxysilane sample 3.
[0045] Example 4: Zeolite Recycling and Reuse Experiment
[0046] The artificial zeolite used in step S4 of Example 1 is recycled without washing. 22 parts of magnesium shavings are added directly and mixed evenly with the zeolite to form the packing layer of the fixed bed reactor. 220 parts of bromopentafluorobenzene and 1760 parts of dry tetrahydrofuran are mixed to obtain a mixed solution. The mixed solution is slowly fed from the bottom to the top of the fixed bed reactor until it is discharged from the top. The mixture is circulated for 5 hours to obtain a tetrahydrofuran solution of pentafluorophenyl magnesium bromide.
[0047] 240 parts of tetraethyl orthosilicate were added to the reaction vessel, and the prepared tetrahydrofuran solution of pentafluorophenyl magnesium bromide was slowly added dropwise. After the addition was completed, the temperature was raised to 35°C, stirred and kept at the temperature for 6 hours. After the reaction was completed, pentafluorophenyl triethoxysilane sample 4 was obtained by vacuum distillation.
[0048] Comparative Example 1
[0049] 24.3 parts magnesium shavings, 0.50 parts iodine granules, and 1760 parts dried tetrahydrofuran were added to a reaction vessel. Under nitrogen protection, bromopentafluorobenzene was slowly added dropwise. After the reaction was initiated, the addition of bromopentafluorobenzene was stopped and the mixture was stirred for 30 minutes. Then, the addition of bromopentafluorobenzene continued until 220 parts of bromopentafluorobenzene were added. The mixture was kept at room temperature for 12 hours to prepare a tetrahydrofuran solution of magnesium pentafluorophenyl bromide.
[0050] 240 parts of tetraethyl orthosilicate were added to the reactor, and the prepared tetrahydrofuran solution of pentafluorophenyl magnesium bromide was slowly added dropwise. After the addition was completed, the temperature was raised to 35°C, stirred and kept at the temperature for 6 hours. After the reaction was completed, pentafluorophenyltriethoxysilane reference standard 1 was obtained by vacuum distillation.
[0051] Comparative Example 2
[0052] 24.3 parts magnesium shavings, 0.50 parts iodine granules, and 1760 parts dried tetrahydrofuran were added to a reaction vessel. Under nitrogen protection, bromopentafluorobenzene was slowly added dropwise. After the reaction was initiated, the addition of bromopentafluorobenzene was stopped and the mixture was stirred for 30 minutes. Then, the addition of bromopentafluorobenzene continued until 220 parts of bromopentafluorobenzene were added. The mixture was then refluxed for 6 hours to prepare a tetrahydrofuran solution of pentafluorophenyl magnesium bromide. Subsequent reactions were carried out using Comparative Example 1, and pentafluorophenyltriethoxysilane reference standard 2 was obtained by vacuum distillation.
[0053] Comparative Example 3
[0054] 24.3 parts magnesium shavings, 0.20 parts iodine granules, and 1760 parts dried tetrahydrofuran were added to a reaction vessel. Under nitrogen protection, bromopentafluorobenzene was slowly added dropwise. After the reaction was initiated, the addition of bromopentafluorobenzene was stopped and the mixture was stirred for 30 minutes. Then, the addition of bromopentafluorobenzene continued until 220 parts of bromopentafluorobenzene were added. The mixture was then refluxed for 12 hours to prepare a tetrahydrofuran solution of pentafluorophenyl magnesium bromide. Subsequent reactions were carried out using Comparative Example 1, and pentafluorophenyltriethoxysilane reference standard 3 was obtained by vacuum distillation.
[0055] Analysis and Testing
[0056] The purity of the samples and reference standards was determined by high performance gas chromatography, and the results are shown in Table 1.
[0057] The sample and the reference standard were weighed, and the yield was calculated using the following formula. The results are shown in Table 1.
[0058] The yield calculation formula is:
[0059] Product yield = Actual weight of the obtained sample (g) / Theoretical yield (g) calculated based on the amount of tetraethyl orthosilicate used × 100%.
[0060] Table 1: Summary of Sample Yield and Purity Test Results
[0061] Sample number Product yield (%) Product purity (%) Product Sample 1 90.2 97.6 Product Sample 2 90.6 97.3 Product Sample 3 90.1 97.4 Product Sample 4 89.6 97.3 Reference Standard 1 85.6 92.1 Reference Standard 2 88.7 95.6 Reference Standard 3 86.5 93.4
[0062] As shown in Table 1, the purity of the pentafluorophenyltriethoxysilane product prepared by this invention can reach over 97.0%, and the product yield can reach approximately 90%. In the preparation process, this invention uses a mixture of artificial zeolite and magnesium shavings as the packing layer in a fixed-bed reactor, which increases the contact area of the reaction substrate and extends the reaction time. The reaction process for preparing Grignard reagents also does not require heating, greatly reducing the generation of byproducts and energy consumption. Furthermore, the soaked zeolite not only eliminates the influence of air in the zeolite pores but also adsorbs some of the soaking solution, synergistically initiating the reaction with iodine particles, thus reducing the amount of iodine particles required.
[0063] The packing layer of zeolite and magnesium filings can be recycled and reused, making full use of the remaining magnesium filings, and there is no need to soak the zeolite again during recycling. However, the number of recycling times is not unlimited. Studies have found that the reaction yield and product purity are greatly reduced during the third cycle. The reaction efficiency can be improved by adding iodine granules and magnesium filings.
[0064] Application testing
[0065] Sample 1 and reference sample 2 were added to the lithium battery electrolyte as electrolyte additives, with the addition amount being 1% of the total mass of the electrolyte. A lithium battery with a capacity of 1000mAh was made using these electrolytes and its performance was tested.
[0066] 1. High-temperature external short-circuit test
[0067] After fully charging the battery, place it in an environment of 55℃±5℃. After the battery surface temperature reaches 55℃±5℃, leave it for another 30 minutes. Then connect the positive and negative terminals of the battery with wires and ensure that the total external resistance is 80mΩ±20mΩ. Monitor the battery temperature change during the test. The battery should not catch fire or explode. The maximum temperature should not exceed 150℃. Record the test phenomena. The test results are shown in Table 2.
[0068] 2. Electrical Cyclic Performance Test
[0069] The test environment temperature was 25℃±2℃. The battery was charged at a constant current of 1C to 4.35V, then charged at a constant voltage to a current of 0.05C, and then discharged at a constant current of 1C to 3.0V. This was the first cycle.
[0070] Under the above cycling conditions, perform 100, 300, and 500 charge / discharge cycles respectively, and calculate the capacity retention rate after 100, 300, and 500 cycles respectively. The capacity retention rate after cycling is calculated using the following formula:
[0071] The capacity retention rate after cycling is calculated as (discharge capacity after the corresponding number of cycles / discharge capacity of the first cycle) × 100%, and the results are shown in Table 2.
[0072] 3. High-voltage electric cycling performance test
[0073] The test environment temperature was 25℃±2℃. The battery was charged to 4.6V with a constant current of 1C, then charged to 0.05C with a constant voltage of 4.6V, and then discharged to 3.0V with a constant current of 1C. This was the first cycle.
[0074] The battery was charged / discharged for 100, 300, and 500 cycles under the conditions described above. The capacity retention rate after 100, 300, and 500 cycles was calculated, and the results are shown in Table 2.
[0075] Table 2: Summary of Battery Performance Test Results
[0076]
[0077] As shown in Table 2, using high-purity pentafluorophenyltriethoxysilane as a lithium salt in the preparation of battery electrolyte helps improve the battery's electrocycle performance, especially its electrocycle performance under high voltage. This is because the pre-oxidation of pentafluorophenyltriethoxysilane reduces the battery's internal resistance, inhibits electrolyte decomposition, and allows for more complete discharge of the battery's active materials. The higher the purity of the additive, the more significant the effect.
Claims
1. A method for preparing pentafluorophenyltriethoxysilane, characterized in that, The preparation method uses bromopentafluorobenzene and tetraethyl orthosilicate as raw materials, and a Grignard reaction is carried out under the action of a catalyst to generate pentafluorophenyltriethoxysilane. The product is obtained by vacuum distillation. The catalyst is magnesium shavings, and the Grignard reaction is carried out in an anhydrous organic solvent with iodine particles as the initiator. The molar ratio of magnesium shavings, bromopentafluorobenzene, tetraethyl orthosilicate and iodine particles is 1:0.8-1.2:0.8-1.2:0.0005-0.
001.
2. The method for preparing pentafluorophenyltriethoxysilane according to claim 1, characterized in that, The anhydrous organic solvent is anhydrous tetrahydrofuran or a mixture of anhydrous tetrahydrofuran and benzene.
3. The method for preparing pentafluorophenyltriethoxysilane according to claim 2, characterized in that, The volume ratio of tetrahydrofuran to benzene in the anhydrous tetrahydrofuran and benzene mixed solvent is 2 to 4:
1.
4. The method for preparing pentafluorophenyltriethoxysilane according to claim 1, characterized in that, The reaction temperature is 30℃~40℃, and the reaction time is 4h~8h.
5. The method for preparing pentafluorophenyltriethoxysilane according to claim 1, characterized in that, The specific reaction steps are as follows: S1. Soak the zeolite in the soaking solution, remove it, drain it, and set it aside; S2. Inert gas is introduced into the fixed-bed reactor, magnesium shavings and iodine granules are mixed, and soaked zeolite is added to form a packing layer. S4. Mix pentafluorobenzene with tetrahydrofuran to obtain a mixed solution. Slowly feed the mixed solution from the bottom to the top of the fixed bed reactor until it is discharged from the top. Circulate the mixed solution for 4 to 6 hours to obtain a tetrahydrofuran solution of pentafluorophenyl magnesium bromide. S5. Add tetraethyl orthosilicate to the reaction vessel, and add the tetrahydrofuran solution of the aforementioned pentafluorophenyl magnesium bromide dropwise. After the addition is complete, heat and stir the reaction. After the reaction is completed, distill under reduced pressure to obtain the pentafluorophenyltriethoxysilane product.
6. The method for preparing pentafluorophenyltriethoxysilane according to claim 5, characterized in that, The particle size ratio of magnesium shavings to zeolite is 1:1.2 to 2.0, and the particle size of magnesium shavings is 1.0 mm to 2.0 mm.
7. The method for preparing pentafluorophenyltriethoxysilane according to claim 5, characterized in that, The soaking time for the zeolite is 0.5h to 1h.
8. The method for preparing pentafluorophenyltriethoxysilane according to claim 5, characterized in that, The zeolite is a synthetic zeolite, composed of sulfonated polystyrene, and can be recycled and reused.
9. The method for preparing pentafluorophenyltriethoxysilane according to claim 5, characterized in that, The soaking solution is any one of iodomethane, iodoethane, and bromobenzene.