A method for large-scale preparation of high-purity, high-yield perfluoroalkyl POSS

Abstract

The invention discloses a method for preparing high-purity and high-yield perfluoroalkyl POSS on a large scale, and belongs to the technical field of POSS (cage-type polysilsesquioxane) synthesis. The invention uses perfluoroalkyltrialkoxysilane as a precursor, a strong base as a catalyst, and a fluorocarbon-type surfactant as an auxiliary agent. The perfluoroalkyl POSS with an octahedral cage structure is prepared through a hydrolysis condensation process assisted by ultrasound and a recrystallization process in a hydrofluoroether solvent. The method has the characteristics of high yield, high purity, and low equipment operation burden, and is suitable for large-scale preparation.

Description

Technical Field

[0001] The invention relates to the technical field of POSS (cage-type polysilsesquioxane) synthesis, and more specifically to a method for large-scale preparation of high-purity and high-yield perfluoroalkyl POSS. Background Art

[0002] Polyhedral oligomeric silsesquioxanes (POSS) are also known as polyhedral oligomeric silsesquioxanes. The structural formula of POSS is Rn(SiO1.5)n. When n=8, it has a classic octahedral structure. Its molecules are mainly composed of an inorganic core formed by silicon-oxygen bonds and an organic group R. The three-dimensional size of the molecule is about 1~5nm, and it has the general properties of nanomaterials. POSS is generally obtained by hydrolyzing trichlorosilane or trialkoxysilane using a sol-gel method under the action of an acidic or alkaline catalyst. However, since the hydrolysis and condensation process is difficult to control, most of the products obtained are random structures, and perfect octahedral cage structures are rare. In order to improve the yield and purity of POSS, on the one hand, it is necessary to increase the cage formation rate by precisely controlling the reaction conditions, and on the other hand, it is necessary to separate the required cage structure through multiple purification processes.

[0003] R is -CH2CH2-C n F 2n+1 POSS is called perfluoroalkyl POSS. In 2007, Joseph M. Mabry's research team reported perfluoroalkyl POSS with n=4, 6, and 8 at ANGEW and studied the relationship between its hydrophobicity and surface microstructure. Subsequently, more research teams studied the performance and application of perfluoroalkyl POSS and found that it has excellent hydrophobicity and oleophobicity, low interfacial friction coefficient and excellent dielectric properties. The nanocomposite prepared by this has super-hydrophobic, super-oleophobic, super-lubricating and anti-icing surface properties, and has broad application prospects. The current methods for synthesizing perfluoroalkyl POSS are all based on the method reported by Joseph M. Mabry, that is, perfluoroalkyl trialkoxysilane is synthesized by hydrolysis and condensation in a specific solvent. Since the cage structure is insoluble in the solvent, it will crystallize and precipitate, thereby obtaining perfluoroalkyl POSS. However, the products with semi-cage structure and linear structure are also insoluble in the solvent, and the semi-cage structure is also crystalline, which greatly increases the difficulty of subsequent purification and leads to reduced yield. At the same time, after crystallization, it is easy to adhere to the stirring paddle and container wall, which puts a great burden on the operation of the equipment, and therefore it is difficult to prepare and apply on a large scale.

[0004] In order to solve the problems in the preparation process of perfluoroalkyl POSS, the present invention provides a method for preparing high-purity and high-yield perfluoroalkyl POSS on a large scale, wherein ultrasonic waves are used to assist the crystallization process in the critical stage of hydrolyzing perfluoroalkyl trialkoxysilane into silanol and entering condensation, and a hydrofluoroether solvent is used to perform recrystallization purification three times after the reaction to obtain high-purity and high-yield perfluoroalkyl POSS. Ultrasonic waves can prevent the semi-cage structure from being encapsulated in the solid crystals and unable to form a closed cage, thereby improving the cage formation rate, and can effectively prevent the solid from adhering to the stirring paddle and the kettle wall after precipitation, thereby reducing the burden of equipment operation, simplifying the subsequent recrystallization and purification process, and improving the yield of perfluoroalkyl POSS, and the method has universality for the synthesis of different types of perfluoroalkyl POSS, and can achieve large-scale preparation. Summary of the invention

[0005] 1. Technical problems to be solved:

[0006] In view of the problems existing in the prior art, the object of the present invention is to provide a method for preparing high-purity and high-yield perfluoroalkyl POSS on a large scale, which overcomes the many shortcomings of laboratory synthesis methods and is more suitable for commercial production. Specifically, perfluoroalkyl trialkoxysilane is used as a precursor for hydrolysis and condensation under the action of an alkaline catalyst, and ultrasonic waves are used to assist in the key stage of cage-forming reaction, which can greatly reduce the proportion of semi-cage products, and can effectively prevent solids from adhering to a stirring paddle and a kettle wall after precipitation. After the reaction is completed, a specific hydrofluoroether solvent is used to prepare perfluoroalkyl POSS after recrystallization and purification. The method has the characteristics of simple reaction conditions, high yield and purity, low equipment operation burden, and strong versatility.

[0007] 2. Technical solution:

[0008] To solve the above problems, the present invention adopts the following technical solutions.

[0009] A method for large-scale preparation of high-purity, high-yield perfluoroalkyl POSS comprises the following synthesis steps:

[0010] S1. Add the precursor, solvent and surfactant into the reaction kettle and stir evenly, and control the reaction temperature to 5-35°C;

[0011] S2, add alkaline catalyst, control the alkalinity to 0.1~1mgKOH / g, stir and react for 2~10h, turn on ultrasound, control the reaction temperature to 20~40℃ and continue the reaction until the total reaction time is 24h;

[0012] S3, adding acetic acid to neutralize;

[0013] S4, collecting the filter cake by filtration under reduced pressure, and washing the filter cake with a hydrofluoroether solvent at 0-10°C to remove the surfactant, linear body and random polymer;

[0014] S5, dissolving the filter cake in a hydrofluoroether solvent to prepare a solution with a concentration of 15-25wt%, washing with deionized water to remove a small amount of acetate therein, transferring the organic phase to a distillation kettle for distillation and concentration to a concentration of 50-60wt%, rapidly cooling to 0-10°C to precipitate crystals, collecting the filter cake by filtration under reduced pressure, and washing the filter cake with a hydrofluoroether solvent at 0-30°C;

[0015] S6, dissolving the filter cake again in a 40-60° C. hydrofluoroether solvent to prepare a solution with a concentration of 50-60 wt%, rapidly cooling to 0-10° C. to precipitate crystals, collecting the filter cake by filtration under reduced pressure, and washing the filter cake with a 0-30° C. hydrofluoroether solvent;

[0016] S7. Put the filter cake into an oven, first dry it at 60°C for 3 hours, then heat it to 120°C and dry it for 1 hour. After natural cooling and crushing, high-purity perfluoroalkyl POSS is obtained.

[0017] A further improvement is that the reactor in step S2 is equipped with a medium-power ultrasonic device of 100W to 500W, and the ultrasonic device must be turned on during the synthesis process.

[0018] A further improvement is that the precursor in step S1 is one of perfluorobutylethyltrimethoxysilane, perfluorobutylethyltriethoxysilane, perfluorohexylethyltrimethoxysilane, perfluorohexylethyltriethoxysilane, perfluorooctylethyltrimethoxysilane, and perfluorooctylethyltriethoxysilane, and its acid value needs to be less than 0.01 mgKOH / g.

[0019] A further improvement is that the solvent used in the reaction in step S1 is one of methanol, ethanol, isopropanol, tetrahydrofuran, dimethyl ether and acetone, and is an anhydrous solvent.

[0020] A further improvement is that the surfactant in step S1 is a non-ionic fluorocarbon surfactant.

[0021] A further improvement is that in step S1, the weight ratio of the precursor, the solvent and the surfactant is 10-50:50-90:0.1-1.5.

[0022] A further improvement is that the alkaline catalyst in step S2 is an aqueous solution composed of 0.2-2 wt % of sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide and tetramethylammonium hydroxide.

[0023] A further improvement is that the hydrofluoroether solvent in step S4 includes one of 3M™ Novec™ 7000, 3M™ Novec™ 7100, 3M™ Novec™ 7200, 3M™ Novec™ 7300, and 3M™ Novec™ 7500.

[0024] 3. Beneficial effects:

[0025] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0026] The invention has a reasonable design, uses ultrasound to assist the crystallization process in the critical stage of hydrolyzing perfluoroalkyltrialkoxysilane into silanol and entering condensation, and uses a hydrofluoroether solvent to perform recrystallization purification three times after the reaction to obtain high-purity and high-yield perfluoroalkyl POSS. Ultrasonic waves can prevent the semi-cage structure from being encapsulated in the solid crystals and unable to form a closed cage, thereby improving the cage formation rate, and can effectively prevent the solid from adhering to the stirring paddle and the kettle wall after precipitation, thereby reducing the burden of equipment operation, simplifying the subsequent recrystallization purification process, and improving the yield of the perfluoroalkyl POSS. The method has universality for the synthesis of different types of perfluoroalkyl POSS, and can achieve large-scale preparation.

[0027] It should be noted that the structures not introduced in the present invention are the same as the prior art or can be implemented by using the prior art, and are not described in detail here because they do not involve the design points and improvement directions of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is the infrared spectrum of the perfluoroalkyl POSS of the present invention;

[0029] Figure 2 Figure 2 is a molecular structure diagram of the perfluoroalkyl POSS of the present invention. DETAILED DESCRIPTION

[0030] To facilitate understanding of the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. Several embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0031] To solve the problems in the prior art, the present invention provides a method for preparing high-purity and high-yield perfluoroalkyl POSS on a large scale, which overcomes the many deficiencies of laboratory synthesis methods and is more suitable for commercial production. Specifically, perfluoroalkyl trialkoxysilane is used as a precursor for hydrolysis and condensation under the action of an alkaline catalyst, and ultrasonic waves are used to assist in the critical stage of cage-forming reaction, which can greatly reduce the proportion of semi-cage products, and can effectively prevent solids from adhering to a stirring paddle and a kettle wall after precipitation. After the reaction is completed, a specific hydrofluoroether solvent is used for recrystallization and purification to prepare perfluoroalkyl POSS. The method has the characteristics of simple reaction conditions, high yield and purity, low equipment operation burden, and strong versatility.

[0032] Specifically, the perfluoroalkyl POSS of the present invention has the following characteristics: Figure 2 The octahedral cage structure shown;

[0033] The group R f It is -CH2CH2CF2CF2CF2CF3, -CH2CH2CF2CF2CF2CF2CF2CF3 or -CH2CH2CF2CF2CF2CF2CF2CF2CF2CF3.

[0034] To synthesize Figure 1 The perfluoroalkyl POSS shown in the figure requires a precursor selected from the group consisting of perfluorobutylethyltrimethoxysilane, perfluorobutylethyltriethoxysilane, perfluorohexylethyltrimethoxysilane, perfluorohexylethyltriethoxysilane, perfluorooctylethyltrimethoxysilane, and perfluorooctylethyltriethoxysilane. The acid value of the precursor needs to be reduced before use to avoid adverse effects on the hydrolysis and condensation process. A variety of methods can be used to reduce the acid value of the precursor, including but not limited to:

[0035] (1) Add anhydrous magnesium sulfate and ground weakly alkaline solid powders such as sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, calcium oxide, aluminum silicate, etc. to the precursor, stir for a long time, and then filter;

[0036] (2) Passing the precursor through a weakly alkaline ion exchange resin column to remove trace amounts of acid;

[0037] (3) Add pyridine, triethylamine and other acid-binding agents to the precursor, stir and react, and then re-distill. Ion exchange resin column is preferred for acid removal. This method is simple in process, does not introduce additional impurities, can be operated at room temperature, has high acid removal efficiency, and can be produced continuously. The acid value after treatment must be less than 0.01 mgKOH / g.

[0038] The synthesis reaction is carried out in a reactor with ultrasonic function. The precursor, solvent and surfactant are added to the reactor and stirred evenly, the reaction temperature is controlled to be 5~35℃, an alkaline catalyst is added, the alkaline value is controlled to be 0.1~1mgKOH / g, the reaction is stirred for 2~10h, the ultrasound is turned on, the reaction temperature is controlled to be 20~40℃ and the reaction is continued until the total reaction time is 24h. Acetic acid is added for neutralization. The filter cake is collected by vacuum filtration, and the filter cake is washed with a hydrofluoroether solvent at 0~10℃ to remove the surfactant, linear body and random polymer. The filter cake is dissolved in a hydrofluoroether solvent to prepare a solution with a concentration of 15~25wt%, washed with deionized water to remove a small amount of acetate, and the organic phase is transferred to a distillation kettle for distillation and concentration to a concentration of 50~60wt%, and the temperature is quickly reduced to 0~10℃ to precipitate crystals, the filter cake is collected by vacuum filtration, and the filter cake is washed with a hydrofluoroether solvent at 0~30℃. The filter cake is dissolved again in a 40-60°C hydrofluoroether solvent to prepare a 50-60wt% solution, and the temperature is quickly reduced to 0-10°C to precipitate crystals. The filter cake is collected by vacuum filtration and washed with a 0-30°C hydrofluoroether solvent. The filter cake is placed in an oven, first dried at 60°C for 3h, then heated to 120°C for 1h, and naturally cooled and crushed to obtain high-purity perfluoroalkyl POSS.

[0039] Specifically, as mentioned above, the solvent is one of methanol, ethanol, isopropanol, tetrahydrofuran, dimethyl ether, and acetone, and is an anhydrous solvent, wherein the mass fraction of the precursor in the solvent is 10-50wt%.

[0040] Specifically, the acid value of the precursor and the base value of the reaction system as described above are tested using the method described in GB / T 4945-2002.

[0041] Specifically, as mentioned above, the surfactant is a fluorinated surfactant, which can effectively improve the crystal agglomeration phenomenon, make the grain distribution more uniform, and prevent the semi-cage structure from being encapsulated in the crystal block and unable to complete the closed cage reaction. This surfactant contains fluorocarbon groups such as perfluoroalkyl and perfluoropolyether, and has hydrophilic groups such as carboxylates, sulfonates, phosphates, and polyoxyethylene. This fluorinated surfactant can be an ionic type, such as Zonyl®FS-610, Zonyl®FSA, Zonyl®FS-62, etc. It can also be a non-ionic type, such as DuPont's Zonyl®FSG, Zonyl®FSN-100, Zonyl®FSO-100, Zonyl®8857A, Zonyl®FS-300, Zonyl®FSO, Dow's Capstone FS-10, 3M's Fluorad FC-4430, Yumu Chemical's YM-313, YM-3016, etc. Ionic and non-ionic surfactants have similar effects in stabilizing crystals. Non-ionic fluorinated surfactants with better solubility in the above-mentioned solvents are preferred, and their usage is 0.1-1.5% of the total mass of the precursor and the solvent.

[0042] Specifically, as mentioned above, the effective ingredient of the alkaline catalyst is one of sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, and tetramethylammonium hydroxide, which is pre-prepared into an aqueous solution with a concentration of 0.2~2wt% for use as a catalyst. On the one hand, it is convenient for accurate use, and on the other hand, it can also provide a trace amount of water required for hydrolysis of the precursor.

[0043] Specifically, as mentioned above, ultrasound plays a key role in the reaction process. By breaking the crystal blocks, the semi-cage polymer can continue to participate in the reaction to complete the cage, and at the same time increase the contact between the catalyst and the intermediate state, but the intervention of ultrasound in the early stage of the reaction will inhibit the cage formation, resulting in an increase in random polymers. Therefore, the appropriate selection of the timing of ultrasound is the key to improving the yield. The opening time of ultrasound is preferably between 2 and 10 hours after the start of the reaction. In the subsequent reaction process, ultrasound can be turned on continuously or intermittently. If intermittent opening is adopted, the time interval between each opening is 0.5 to 3 hours, and the duration after each ultrasound opening is 10 to 60 minutes. Medium-power ultrasound with a power of 100W to 500W should be selected, preferably 300W to 500W.

[0044] Specifically, as mentioned above, the hydrofluoroether solvent should have better solubility for random polymers and semi-cage polymers, and the solubility for perfluoroalkyl POSS changes with temperature. Hydrofluoroether solvents that meet the above requirements include 3M™ Novec™ 7000, 3M™ Novec™ 7100, 3M™ Novec™ 7200, 3M™ Novec™ 7300, and 3M™ Novec™ 7500.

[0045] In this embodiment, the filter cake is purified by multiple crystallizations in steps S5 and S6 to remove the amorphous part and improve the purity. The solvent temperature for washing the filter cake is 0-30°C and the dissolution temperature is 40-60°C. Therefore, the temperature difference is 10-60°C, which has a wide range of application. At the same time, the acetate is physically separated and does not involve reaction.

[0046] In this embodiment, 3M stands for Minnesota Mining and Manufacturing, and novec is the name of 3M's product series. The number behind it represents the model number, which is the complete product name of 3M's products.

[0047] R f The group in is one of perfluorobutyl, perfluorohexyl and perfluorooctyl.

[0048] Embodiment 1:

[0049] Add 500g perfluorobutylethyltrimethoxysilane, 4500g methanol, and 5g Zonyl®FSG into the reactor and stir evenly. Control the reaction temperature to 5°C. Add 178.43g sodium hydroxide solution with a mass concentration of 0.2wt%. Take a sample to test the alkali content. Control the alkali value to 0.1mgKOH / g. Stir and react for 2h. Continue to turn on ultrasound during the subsequent reaction. Control the reaction temperature to 20°C and continue the reaction until the total reaction time is 24h. Add 0.64g acetic acid for neutralization. Collect the filter cake by vacuum filtration and wash the filter cake with 3M™ Novec™ 7000 solvent at 0°C to remove surfactants, linear bodies and random polymers. The filter cake was dissolved in 3M™ Novec™ 7000 to prepare a 15wt% solution, washed with deionized water to remove a small amount of acetate, and the organic phase was transferred to a distillation kettle for distillation and concentration to a concentration of 50wt%, and the temperature was rapidly reduced to 0°C to precipitate crystals, and the filter cake was collected by vacuum filtration, and the filter cake was washed with 0°C 3M™ Novec™ 7000. The filter cake was dissolved in 3M™ Novec™ 7000 at 40°C to prepare a 50wt% solution, and the temperature was rapidly reduced to 0°C to precipitate crystals, and the filter cake was collected by vacuum filtration, and the filter cake was washed with 0°C 3M™ Novec™ 7000. The filter cake was placed in an oven, first dried at 60°C for 3h, then heated to 120°C for 1h, and naturally cooled and crushed to obtain R. f It is a perfluoroalkyl POSS of perfluorobutylethyl.

[0050] Embodiment 2:

[0051] Add 1000g perfluorobutylethyltriethoxysilane, 4000g ethanol, and 75g Zonyl® FSO-100 to the reactor and stir evenly. Control the reaction temperature to 20°C. Add 507.5g potassium hydroxide solution with a mass concentration of 1wt%, take a sample to test the alkali content, control the alkali value to 1mgKOH / g, stir and react for 6h, then start ultrasound every 0.5h, the duration of ultrasound is 10min, control the reaction temperature to 30°C and continue the reaction until the total reaction time is 24h. Add 6.52g acetic acid for neutralization. Collect the filter cake by vacuum filtration, and wash the filter cake with 3M™ Novec™ 7100 at 10°C to remove surfactants, linear bodies and random polymers. The filter cake was dissolved in 3M™ Novec™ 7100 solvent to prepare a 25wt% solution, washed with deionized water to remove a small amount of acetate, and the organic phase was transferred to a distillation kettle for distillation and concentration to a concentration of 60wt%, and the temperature was rapidly reduced to 10°C to precipitate crystals, and the filter cake was collected by vacuum filtration, and the filter cake was washed with 20°C 3M™ Novec™ 7100 solvent. The filter cake was dissolved again in 60°C 3M™ Novec™ 7100 solvent to prepare a 60wt% solution, and the temperature was rapidly reduced to 5°C to precipitate crystals, and the filter cake was collected by vacuum filtration, and the filter cake was washed with 20°C 3M™ Novec™ 7100 solvent. The filter cake was placed in an oven, first dried at 60°C for 3h, then heated to 120°C and dried for 1h, and naturally cooled and crushed to obtain R. f It is a perfluoroalkyl POSS of perfluorobutylethyl.

[0052] Embodiment 3:

[0053] Add 1500g perfluorohexylethyltrimethoxysilane, 3500g isopropanol, and 12.5g Zonyl® FSO to the reactor and stir evenly. Control the reaction temperature to 10°C. Add 125.31g potassium hydroxide solution with a mass concentration of 2wt%. Take a sample to test the alkali content. Control the alkali value to 0.5mgKOH / g. Stir the reaction for 4h. Then start ultrasound every 3h. The duration of ultrasound is 60min. Control the reaction temperature to 30°C and continue the reaction until the total reaction time is 24h. Add 3.22g acetic acid for neutralization. Collect the filter cake by vacuum filtration and wash the filter cake with 3M™ Novec™ 7200 at 5°C to remove surfactants, linear bodies and random polymers. The filter cake was dissolved in 3M™ Novec™ 7200 to prepare a 15wt% solution, washed with deionized water to remove a small amount of acetate, and the organic phase was transferred to a distillation kettle for distillation and concentration to a concentration of 55wt%, and the temperature was rapidly reduced to 0°C to precipitate crystals, and the filter cake was collected by vacuum filtration, and the filter cake was washed with 0°C 3M™ Novec™ 7200. The filter cake was dissolved again in 60°C 3M™ Novec™ 7200 solvent to prepare a 55wt% solution, and the temperature was rapidly reduced to 0°C to precipitate crystals, and the filter cake was collected by vacuum filtration, and the filter cake was washed with 0°C hydrofluoroether solvent. The filter cake was placed in an oven, first dried at 60°C for 3h, then heated to 120°C for 1h, and naturally cooled and crushed to obtain R. f The perfluoroalkyl POSS is perfluorohexylethyl.

[0054] Embodiment 4:

[0055] Add 1500g perfluorohexylethyltriethoxysilane, 3500g tetrahydrofuran, and 25g Capstone FS-10 to the reactor and stir evenly. Control the reaction temperature to 35°C. Add 204.11g tetramethylammonium hydroxide solution with a mass concentration of 1wt%, take a sample to test the alkali content, control the alkali value to 0.25mgKOH / g, stir and react for 10h, then start ultrasound every 1h, the duration of ultrasound is 20min, control the reaction temperature to 35°C and continue the reaction until the total reaction time is 24h. Add 1.61g acetic acid to neutralize. Collect the filter cake by vacuum filtration, and wash the filter cake with 3M™ Novec™ 7300 at 10°C to remove surfactants, linear bodies and random polymers. The filter cake was dissolved in 3M™ Novec™ 7300 to prepare a 25wt% solution, washed with deionized water to remove a small amount of acetate, and the organic phase was transferred to a distillation kettle for distillation and concentration to a concentration of 50wt%. The temperature was rapidly reduced to 5°C to precipitate crystals, and the filter cake was collected by vacuum filtration and washed with 3M™ Novec™ 7300 at 30°C. The filter cake was dissolved in 3M™ Novec™ 7300 at 60°C to prepare a 60wt% solution, and the temperature was rapidly reduced to 5°C to precipitate crystals. The filter cake was collected by vacuum filtration and washed with 3M™ Novec™ 7300 at 30°C. The filter cake was placed in an oven, first dried at 60°C for 3h, then heated to 120°C and dried for 1h, and then naturally cooled and crushed to obtain R. f The perfluoroalkyl POSS is perfluorohexylethyl.

[0056] Embodiment 5:

[0057] 2000g perfluorooctylethyltrimethoxysilane, 3000g acetone, and 37.5g Fluorad FC-4430 were added to the reactor and stirred evenly. The reaction temperature was controlled to 25°C. 2019.17g of cesium hydroxide solution with a mass concentration of 0.5wt% was added. Samples were taken to test the alkali content. The alkali value was controlled to be 0.75mgKOH / g. The reaction was stirred for 7h. After that, ultrasound was turned on every 1.5h. The duration of ultrasound was 30min. The reaction temperature was controlled to 25°C and the reaction was continued until the total reaction time was 24h. 4.85g acetic acid was added for neutralization. The filter cake was collected by vacuum filtration and cleaned with 3M™ Novec™ 7300 at 5°C to remove surfactants, linear bodies, and random polymers. The filter cake was dissolved in 3M™ Novec™ 7300 to prepare a 20wt% solution, washed with deionized water to remove a small amount of acetate, and the organic phase was transferred to a distillation kettle for distillation and concentration to a concentration of 60wt%, and the temperature was rapidly reduced to 5°C to precipitate crystals, and the filter cake was collected by vacuum filtration, and the filter cake was washed with 0°C 3M™ Novec™ 7300. The filter cake was dissolved in 3M™ Novec™ 7300 at 60°C to prepare a 60wt% solution, and the temperature was rapidly reduced to 5°C to precipitate crystals, and the filter cake was collected by vacuum filtration, and the filter cake was washed with 0°C 3M™ Novec™ 7300. The filter cake was placed in an oven, first dried at 60°C for 3h, then heated to 120°C for 1h, and naturally cooled and crushed to obtain R. f It is a perfluoroalkyl POSS of perfluorooctylethyl.

[0058] Embodiment 6:

[0059] Add 2500g perfluorooctylethyltriethoxysilane, 2500g ethanol, and 50g YM-3016 to the reactor and stir evenly. Control the reaction temperature to 15°C. Add 115.31g of 2wt% rubidium hydroxide solution. Take a sample to test the alkali content. Control the alkali value to 0.25mgKOH / g. Stir and react for 6h. Then start ultrasound every 2h. The duration of ultrasound is 30min. Control the reaction temperature to 25°C and continue the reaction until the total reaction time is 24h. Add 1.62g acetic acid to neutralize. Collect the filter cake by vacuum filtration and wash the filter cake with 3M™ Novec™ 7500 at 5°C to remove surfactants, linear bodies and random polymers. The filter cake was dissolved in 3M™ Novec™ 7500 to prepare a 20wt% solution, washed with deionized water to remove a small amount of acetate, and the organic phase was transferred to a distillation kettle for distillation and concentration to a concentration of 50wt%, and the temperature was rapidly reduced to 0°C to precipitate crystals, and the filter cake was collected by vacuum filtration, and the filter cake was washed with 0°C 3M™ Novec™ 7500. The filter cake was dissolved in 50°C 3M™ Novec™ 7500 again to prepare a 50wt% solution, and the temperature was rapidly reduced to 0°C to precipitate crystals, and the filter cake was collected by vacuum filtration, and the filter cake was washed with 0°C 3M™ Novec™ 7500. The filter cake was placed in an oven, first dried at 60°C for 3h, then heated to 120°C for 1h, and naturally cooled and crushed to obtain R. f It is a perfluoroalkyl POSS of perfluorooctylethyl.

[0060] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for large-scale preparation of high-purity, high-yield perfluoroalkyl POSS, characterized in that: The synthesis steps include: S1. Add the precursor, solvent and surfactant into a reaction kettle and stir evenly, and control the reaction temperature to be 5-35°C. The surfactant is a fluorine-containing surfactant; S2, add alkaline catalyst, control the alkalinity to 0.1~1mgKOH / g, stir and react for 2~10h, turn on ultrasound, control the reaction temperature to 20~40℃ and continue the reaction until the total reaction time is 24h; S3, adding acetic acid to neutralize; S4, collecting the filter cake by filtration under reduced pressure, and washing the filter cake with a hydrofluoroether solvent at 0-10°C to remove the surfactant, linear body and random polymer; S5, dissolving the filter cake in a hydrofluoroether solvent to prepare a solution with a concentration of 15-25wt%, washing with deionized water to remove a small amount of acetate therein, transferring the organic phase to a distillation kettle for distillation and concentration to a concentration of 50-60wt%, rapidly cooling to 0-10°C to precipitate crystals, collecting the filter cake by filtration under reduced pressure, and washing the filter cake with a hydrofluoroether solvent at 0-30°C; S6, dissolving the filter cake again in a 40-60° C. hydrofluoroether solvent to prepare a solution with a concentration of 50-60 wt%, rapidly cooling to 0-10° C. to precipitate crystals, collecting the filter cake by filtration under reduced pressure, and washing the filter cake with a 0-30° C. hydrofluoroether solvent; S7, put the filter cake into an oven, first dry it at 60 ° C for 3 hours, then heat it to 120 ° C and dry it for 1 hour, and then naturally cool and crush it to obtain high-purity perfluoroalkyl POSS; The reactor in step S2 is equipped with a medium-power ultrasonic device of 100W to 500W, and the ultrasonic device must be turned on during the synthesis process; In the step S1, the precursor is one of perfluorobutylethyltrimethoxysilane, perfluorobutylethyltriethoxysilane, perfluorohexylethyltrimethoxysilane, perfluorohexylethyltriethoxysilane, perfluorooctylethyltrimethoxysilane, and perfluorooctylethyltriethoxysilane, and its acid value must be less than 0.01 mgKOH / g.

2. A method for large-scale preparation of high-purity, high-yield perfluoroalkyl POSS according to claim 1, characterized in that: The solvent used in the reaction in step S1 is one of methanol, ethanol, isopropanol, tetrahydrofuran, dimethyl ether and acetone, and is an anhydrous solvent.

3. A method for large-scale preparation of high-purity, high-yield perfluoroalkyl POSS according to claim 1, characterized in that: The surfactant in step S1 is a non-ionic fluorocarbon surfactant.

4. A method for large-scale preparation of high-purity, high-yield perfluoroalkyl POSS according to claim 1, characterized in that: In the step S1, the weight ratio of the precursor, the solvent and the surfactant is 10-50:50-90:0.1-1.

5.

5. A method for large-scale preparation of high-purity, high-yield perfluoroalkyl POSS according to claim 1, characterized in that: In the step S2, the alkaline catalyst is an aqueous solution composed of 0.2-2 wt % of sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide and tetramethylammonium hydroxide.

6. A method for large-scale preparation of high-purity, high-yield perfluoroalkyl POSS according to claim 1, characterized in that: The hydrofluoroether solvent in step S4 includes one of 3M™ Novec™ 7000, 3M™ Novec™ 7100, 3M™ Novec™ 7200, 3M™ Novec™ 7300, and 3M™ Novec™ 7500.

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