Carbon-terminated functionalized polysiloxane and preparation method thereof

Abstract

The invention discloses end-group carbon functionalized polysiloxane and a preparation method thereof, and belongs to the technical field of organic silicon industry. The preparation method of the carbon-terminated functionalized polysiloxane comprises the following steps: (1) mixing hydroxyl-terminated polysiloxane, chlorosilane and an acid-binding agent, and stirring and reacting under the protection of nitrogen to obtain a reaction solution a; (2) adding an organic solvent into the reaction liquid a, uniformly stirring, adding alkali liquor, and stirring to react until a system is neutral, so as to obtain reaction liquid b; (3) adding a drying agent into the reaction solution b, stirring, drying and filtering to obtain a reaction solution c; and (4) carrying out reduced pressure distillation on the reaction liquid c, and recovering the solvent to obtain the carbon-terminated functionalized polysiloxane. The carbon-terminated polysiloxane is prepared through the reaction of chlorosilane and hydroxyl-terminated polysiloxane, the preparation method is simple, the reaction is economical and efficient, the completely-terminated carbon-terminated polysiloxane can be prepared on a large scale, meanwhile, no waste gas or waste water is generated, and the method is safe and environmentally friendly.

Description

Technical Field

[0001] The present application relates to a terminal carbon functionalized polysiloxane and a preparation method thereof, and belongs to the technical field of organic silicon industry. Background Art

[0002] Polysiloxane is a polymer containing silicon in its molecular structure and with organic groups attached to the silicon atoms. Therefore, it has the dual characteristics of organic and inorganic materials, and has excellent properties such as high and low temperature resistance, weather resistance, radiation resistance, aging resistance, corrosion resistance, electrical insulation, flame retardancy, hydrophobicity, and physiological inertness. These excellent properties of silicone products are incomparable and irreplaceable by other organic polymer materials, so they are widely used in aerospace, electronics and electrical, light industry, chemical industry, textiles, machinery, construction, transportation, medical care, and daily life.

[0003] By introducing reactive functional groups, such as silane, vinyl, chlorocarbon and other groups, at the end of the polysiloxane molecular chain, it becomes an active polysiloxane, which can be used for copolymerization modification of polymers or preparation of functional materials, greatly broadening the application scenarios of silicone materials.

[0004] At present, the preparation of polysiloxane generally adopts acidic or alkaline catalysts, and in the presence of end-capping agents, the ring bodies such as methyl ring bodies, phenyl ring bodies, trifluoropropyl ring bodies, etc. are homopolymerized or copolymerized to obtain them. Due to the different end-capping agents (such as water, vinyl double end-capping, hydrogen-containing double end-capping), hydroxyl-terminated polysiloxane, vinyl-terminated polysiloxane, and hydrogen-terminated polysiloxane are obtained, and then applied in different fields. However, the end-capping efficiency of the above-mentioned end-capping method depends on the reactivity ratio between the cyclic monomer and the end-capping agent, and the ring-opening activity of the cyclic monomer is affected by the side chain group. When one methyl group in D4 (octamethylcyclotetrasiloxane) is replaced by trifluoropropyl, the polymerization rate of cyclotetrasiloxane is 1.5 times the original; when it is replaced by a phenyl group, it is about 4 times the original; when it is replaced by a γ-cyanopropyl group, it is 440 times the original. Therefore, for methyl polysiloxane, the chain breaking or ring opening activity of the end-capping agent and the cyclic monomer is not much different, and a well-end-capped end-functionalized polysiloxane can be obtained. However, for functional monomers with special functional groups such as phenyl and trifluoropropyl in the side groups, the difference between their ring opening activity and the chain breaking activity of the end-capping agent is large, resulting in low end-capping efficiency. Therefore, the end-capping method of this type of polysiloxane has always been an industry problem. In addition, carbon functional end groups are prone to side reactions, and there are very few types of end-capping agents that can be added during the polymerization process, and only a few end-capping structures can be obtained.

[0005] Chinese patent document CN103642046A discloses a method for preparing a vinyl-terminated fluorosilicone oil, which uses a hydroxyl-terminated fluorosilicone oil or its acetone solution to react with (N,N-dialkylamino)dimethylvinylsilane to prepare a vinyl-terminated fluorosilicone oil. However, the preparation of the above-mentioned end-capping agent (N,N-dialkylamino)dimethylvinylsilane is relatively complicated and costly, and is not suitable for industrial production. Summary of the invention

[0006] In order to solve the above problems, the present application provides a terminal carbon-functionalized polysiloxane and a preparation method thereof, wherein the terminal carbon-functionalized polysiloxane is prepared by reacting chlorosilane with terminal hydroxyl polysiloxane. The preparation method is simple, the reaction is economical and efficient, and fully capped terminal carbon-functionalized polysiloxane can be prepared in large quantities. At the same time, no waste gas or wastewater is generated, and it is safe and environmentally friendly.

[0007] According to one aspect of the present application, a method for preparing a terminal carbon functionalized polysiloxane is provided, comprising the following steps: (1) After mixing terminal hydroxyl polysiloxane, chlorosilane and an acid binding agent, stirring and reacting under nitrogen protection to obtain a reaction solution a; (2) Add an organic solvent to the reaction solution a, stir evenly, add an alkali solution, stir and react until the system becomes neutral, and obtain a reaction solution b; (3) Add a desiccant to the reaction solution b, stir to dry, and filter to obtain a reaction solution c; (4) subjecting the reaction solution c to reduced pressure distillation to recover the solvent and obtain terminal carbon functionalized polysiloxane; The structural formula of the chlorosilane is shown in formula (1), Formula (1), Among them, R3, R4, and R5 are selected from one or more of methyl, ethyl, propyl, butyl, vinyl, allyl, phenyl, hydrogen, chloromethyl, chloropropyl, trifluoropropyl, and perfluorooctyl, and R3, R4, and R5 can be the same or different.

[0008] Specifically, the chlorosilane includes dimethylvinylchlorosilane, dimethylallylchlorosilane, trivinylchlorosilane, dimethylphenylchlorosilane, triphenylchlorosilane, trimethylchlorosilane, triethylchlorosilane, tributylchlorosilane, chloromethyldimethylchlorosilane, chloropropyldimethylchlorosilane or perfluorooctyldimethylchlorosilane.

[0009] Specifically, the reaction principle is as follows:

[0010] Wherein, m, n, x are the degree of polymerization, m≥0, n≥0, x≥0, 10≤(m+n+x)≤10000; R1 and R2 are selected from one or more of methyl, ethyl, phenyl, and trifluoropropyl, and R1 and R2 may be the same or different; R3, R4, and R5 are selected from one or more of methyl, ethyl, propyl, butyl, vinyl, allyl, phenyl, hydrogen, chloromethyl, chloropropyl, trifluoropropyl, and perfluorooctyl, and R3, R4, and R5 may be the same or different.

[0011] Optionally, the structural formula of the hydroxyl-terminated polysiloxane is as shown in formula (2), Formula (2), Wherein, m, n, x are the degree of polymerization, m≥0, n≥0, x≥0, 10≤(m+n+x)≤10000; R1 and R2 are selected from one or more of methyl, ethyl, phenyl, and trifluoropropyl, and R1 and R2 may be the same or different.

[0012] Preferably, 40≤(m+n+x)≤5000.

[0013] Optionally, the acid binding agent is selected from one or more of pyridine, N,N-diisopropylethylamine, 4-dimethylaminopyridine, triethanolamine, triethylamine, potassium carbonate, ammonium carbonate, and sodium carbonate.

[0014] Optionally, the organic solvent is selected from one or more of acetone, dichloromethane, dioxane, tetrahydrofuran, petroleum ether, cyclohexane, and toluene; the alkali solution is selected from one or more of ammonia water, sodium hydroxide aqueous solution, potassium hydroxide aqueous solution, sodium carbonate aqueous solution, and sodium bicarbonate aqueous solution.

[0015] Optionally, the desiccant is selected from one or more of anhydrous calcium chloride, anhydrous magnesium sulfate, anhydrous potassium carbonate, anhydrous magnesium sulfate, anhydrous calcium sulfate, molecular sieves, and anhydrous sodium sulfate.

[0016] Optionally, in step (1), the reaction temperature is 0°C to 100°C, the reaction time is 0.5h to 12h; the mass of the chlorosilane is 0.1% to 50% of the mass of the terminal hydroxyl polysiloxane; and the mass of the acid binding agent is 10% to 100% of the mass of the chlorosilane.

[0017] Preferably, the mass of the chlorosilane is 0.1% to 10% of the mass of the terminal hydroxyl polysiloxane, and the mass of the acid binding agent is 10% to 50% of the mass of the chlorosilane.

[0018] Specifically, when the mass of chlorosilane is less than 0.1% of the mass of terminal hydroxyl polysiloxane, terminal hydroxyl residues will remain, making it difficult to prepare terminal carbon functional silicone oil with complete end-capping and good performance; when the mass of chlorosilane is greater than 50% of the mass of terminal hydroxyl polysiloxane, although qualified products can be prepared, the reaction economy will be greatly reduced.

[0019] Preferably, when (m+n+x) of the terminal hydroxyl polysiloxane is 40, the minimum amount of chlorosilane is 20% of the mass of the terminal hydroxyl polysiloxane; when (m+n+x) of the terminal hydroxyl polysiloxane is 5000, the minimum amount of chlorosilane is 0.01% of the mass of the terminal hydroxyl polysiloxane.

[0020] Optionally, in step (2), the stirring reaction time is 0.5 h to 6 h; the mass of the organic solution is 0% to 1000% of the mass of the terminal hydroxyl polysiloxane; and the mass fraction of the alkali solution is 1% to 50%.

[0021] Preferably, the mass of the organic solution is 0% to 200% of the mass of the terminal hydroxyl polysiloxane; and the mass fraction of the alkali solution is 5% to 20%.

[0022] Optionally, in step (3), the stirring and drying time is 1 h to 24 h; the mass of the desiccant is 1% to 500% of the mass of the alkali solution; in step (4), the temperature of the reduced pressure distillation is 30° C. to 150° C., and the time is 1 h to 6 h.

[0023] Preferably, the mass of the desiccant is 20% to 200% of the mass of the alkali solution.

[0024] Specifically, the filtration step in step (3) includes reduced pressure filtration or pressurized filtration.

[0025] Specifically, the solvent recovered in step (4) can be reused.

[0026] According to another aspect of the present application, there is also provided a terminal carbon functionalized polysiloxane, which is prepared by the above-mentioned preparation method.

[0027] The beneficial effects of this application include but are not limited to: 1. According to the preparation method of terminal carbon functionalized polysiloxane of the present application, terminal carbon functionalized polysiloxane is prepared by reacting chlorosilane with terminal hydroxyl polysiloxane. The preparation method is simple, the reaction is economical and efficient, and fully capped terminal carbon functionalized polysiloxane can be prepared in large quantities. At the same time, no waste gas or wastewater is generated, and it is safe and environmentally friendly.

[0028] 2. According to the preparation method of the terminal carbon functionalized polysiloxane of the present application, the raw materials are simple and easy to obtain, the end capping can be carried out quickly and efficiently under mild conditions, the reaction controllability is good, thereby forming various types of terminal carbon functionalized polysiloxanes, which are particularly suitable for the preparation of terminal carbon functionalized polysiloxanes with large differences in reaction activity between cyclic monomers such as methylphenyl polysiloxane and methyltrifluoropropyl polysiloxane and the end capping agent, and no drying solvent and silazane end capping agent with complicated preparation process are required, which greatly reduces the production cost and improves the production efficiency.

[0029] 3. According to the preparation method of terminal carbon functionalized polysiloxane of the present application, the excess chlorosilane is completely hydrolyzed and neutralized by alkaline solution, thereby avoiding acid or alkali residue and improving the thermal stability of the product; the desiccant is used to adsorb or bind water to remove the moisture in the system, so that various salts are precipitated and then filtered out, thereby avoiding the problem of generating a large amount of industrial wastewater by decompression dehydration or multiple water washings, which is economical and environmentally friendly.

[0030] 4. The terminal carbon functionalized polysiloxane according to the present application has low cost, good end-capping effect, and can be produced in large quantities to adapt to industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings: Figure 1 This is the thermogravimetric curve of the terminal chloropropyl fluorosilicone oil prepared in Example 1 in air.

[0032] Figure 2 It is a commercially available vinyl-terminated fluorosilicone oil. 1 HNMR spectrum.

[0033] Figure 3 The vinyl-terminated fluorosilicone oil prepared in Example 2 1 HNMR spectrum.

[0034] Figure 4 The vinyl-terminated fluorosilicone oil prepared in Example 2 29 SiNMR spectrum.

[0035] Figure 5 The trivinyl fluorosilicone oil prepared in Example 3 1 HNMR spectrum.

[0036] Figure 6 The trivinyl fluorosilicone oil prepared in Example 3 29 SiNMR spectrum.

[0037] Figure 7The vinyl-terminated methyl side vinyl phenyl silicone oil prepared in Example 5 1 HNMR spectrum.

[0038] Figure 8 The vinyl-terminated fluorosilicone oil prepared in Comparative Example 1 is 1 HNMR spectrum. DETAILED DESCRIPTION

[0039] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0040] Unless otherwise specified, the raw materials in the examples and comparative examples of the present application were purchased through commercial channels.

[0041] Unless otherwise specified, the methods used in the examples and comparative examples of the present application are conventional methods in the prior art.

[0042] Example 1 ⑴ Pour 10kg 5000mPa•s terminal hydroxyl fluorosilicone oil into a 30L reactor, keep the temperature constant after the reactor reaches 0℃, add 245g pyridine under nitrogen protection, stir mechanically for 20min, add 870g chloropropyldimethylsilyl chloride, stir and react for 1h to obtain reaction solution a; (2) Add 325.6 g of 25% sodium hydroxide aqueous solution to the reaction solution a, and stir the reaction for 0.5 h until the system becomes neutral to obtain a reaction solution b; ⑶ Add 1000 g of anhydrous sodium sulfate to the reaction solution b, stir and dry for 24 h, and filter to obtain a reaction solution c; (4) The reaction solution c was distilled under reduced pressure at 150°C for 5 h to obtain terminal chloropropyl fluorosilicone oil with a viscosity of 4800 mPa•s.

[0043] The thermogravimetric curve of the chloropropyl-terminated fluorosilicone oil prepared in Example 1 in air is as follows: Figure 1 As shown by Figure 1 It can be seen that when the sample weight loss = -4.984%, that is, when the sample weight loss is close to 5%, the temperature is 363.20°C, indicating that the initial decomposition temperature of the sample is relatively high and has good thermal stability; when the sample weight loss = -10.006%, that is, when the sample weight loss is close to 10%, the temperature is 401.17°C; the maximum weight loss rate temperature Tmax is 454.02°C; when the test temperature is 800.44°C, the sample weight loss = -81.776%, and the residual mass is 18.224%, indicating that the silicone oil prepared in Example 1 has good thermal stability.

[0044] Example 2 ⑴ Pour 10kg 20000mPa•s terminal hydroxyl fluorosilicone oil into a 30L reactor, keep the temperature at 30°C, add 45g triethylamine under nitrogen protection, stir mechanically for 30min, add 331g dimethylvinylchlorosilane, stir and react for 12h to obtain reaction solution a; (2) Add 500 g of toluene to the reaction solution a, stir evenly, then add 1825 g of a 20% sodium bicarbonate aqueous solution, stir and react for 0.5 h until the system becomes neutral, to obtain a reaction solution b; ⑶ Add 300 g of molecular sieves to the reaction solution b, stir and dry for 12 h, and filter to obtain a reaction solution c; (4) The reaction solution c was distilled at 65°C under reduced pressure for 1 h to recover 498 g of toluene, and then distilled at 150°C under reduced pressure for 3 h to obtain vinyl-terminated fluorosilicone oil with a viscosity of 18000 mPa•s.

[0045] Example 2: Vinyl-terminated fluorosilicone oil prepared 1 HNMR spectra and 29 SiNMR spectrum Figure 3 and Figure 4 As shown. Figure 3 and Figure 4 It can be seen that the prepared vinyl-terminated fluorosilicone oil is well capped, and the hydroxyl peak disappears completely; Figure 2 It is a commercially available vinyl-terminated fluorosilicone oil. 1 HNMR spectrum, by Figure 2 It can be seen that the commercially available vinyl-terminated fluorosilicone oil has an obvious hydroxyl peak and a low vinyl termination rate.

[0046] Example 3 ⑴ Pour 10 kg of 80000 mPa•s terminal hydroxyl fluorosilicone oil into a 30 L reactor, keep the temperature at 80°C, add 5 g of pyridine under nitrogen protection, stir mechanically for 30 min, add 15 g of trivinyl chlorosilane, stir and react for 4 h to obtain reaction solution a; (2) Add 20 kg of dioxane to the reaction solution a, stir evenly, then add 10 g of ammonia water, stir and react for 2 h until the system becomes neutral, to obtain reaction solution b; ⑶ Add 10 g of anhydrous magnesium sulfate to the reaction solution b, stir and dry for 1 h, and filter to obtain a reaction solution c; (4) The reaction solution c was distilled at 80°C under reduced pressure for 2 h to recover 19995 g of dioxane, and then distilled at 150°C under reduced pressure for 1 h to obtain terminal trivinyl fluorosilicone oil with a viscosity of 79000 mPa•s.

[0047] Example 3 Preparation of trivinyl fluorosilicone oil 1 HNMR spectra and 29 SiNMR spectrum Figure 5 and Figure 6 As shown. Figure 5 and Figure 6 It can be seen that the prepared trivinyl fluorosilicone oil is well capped, the hydroxyl peak disappears completely, and the Si connected to the trivinyl group peaks at δ=25.51, which is different from the Si connected to the vinyl group in the vinyl-terminated silicone oil at δ=33.69.

[0048] Example 4 ⑴ Pour 2kg 4000000mPa•s terminal hydroxy dimethyl silicone oil into a 30L reactor, keep the temperature at 60°C, add 0.2g triethylamine under nitrogen protection, stir mechanically for 30min, add 2g trimethylchlorosilane, stir and react for 2h to obtain reaction solution a; (2) Add 20 kg of tetrahydrofuran to the reaction solution a, stir evenly, then add 3.3 g of a 1% sodium bicarbonate aqueous solution, stir and react for 0.5 h until the system becomes neutral, to obtain a reaction solution b; ⑶ Add 16.5 g of anhydrous magnesium sulfate to the reaction solution b, stir and dry for 8 h, and filter to obtain a reaction solution c; (4) The reaction solution c was distilled under reduced pressure at room temperature for 2 h to recover 19990 g of tetrahydrofuran, and then distilled under reduced pressure at 150° C. for 5 h to obtain methyl-terminated polydimethylsiloxane with a viscosity of 4000000 mPa•s.

[0049] Example 5 (1) Pour 10 kg 10000 mPa•s hydroxy-terminated methyl vinyl phenyl silicone oil (vinyl content 1%, phenyl content 20%) into a 30 L reactor, keep the temperature constant after the reactor reaches 40°C, add 60 g pyridine under nitrogen protection, stir mechanically for 2 h, add 177 g dimethylvinyl chlorosilane, stir and react for 8 h to obtain reaction solution a; (2) Add 1000 g of toluene to the reaction solution a, stir evenly, then add 130 g of aqueous ammonia, stir and react for 2 h until the system becomes neutral, to obtain reaction solution b; ⑶ Add 100 g of anhydrous calcium chloride to the reaction solution b, stir and dry for 10 h, and filter to obtain the reaction solution c5; (4) The reaction solution c was distilled at 70°C under reduced pressure for 2 hours to recover 999 g of toluene, and then distilled at 150°C under reduced pressure for 5 hours to obtain vinyl-terminated methyl side vinyl phenyl silicone oil with a viscosity of 9500 mPa•s.

[0050] Figure 7 The vinyl-terminated methyl side vinyl phenyl silicone oil prepared in Example 5 1 The HNMR spectrum shows that the silicone oil is well capped.

[0051] Example 6 ⑴ Pour 10kg 2000mPa•s terminal hydroxyl fluorosilicone oil into a 30L reactor, keep the temperature at 50°C, add 5000g 4-dimethylaminopyridine under nitrogen protection, stir mechanically for 20min, add 5000g trimethylchlorosilane, stir and react for 18h to obtain reaction solution a; (2) Add 540.6 g of 50% sodium carbonate aqueous solution to the reaction solution a, and stir the reaction for 6 h until the system becomes neutral to obtain a reaction solution b; ⑶ Add 5.4 g of anhydrous potassium carbonate to the reaction solution b, stir and dry for 15 h, and filter to obtain a reaction solution c; (4) The reaction solution c was distilled under reduced pressure at 150°C for 4 h to obtain terminal methyl fluorosilicone oil with a viscosity of 1900 mPa•s.

[0052] Example 7 ⑴ Pour 5kg of 60000mPa•s terminal hydroxyl fluorosilicone oil into a 30L reactor, keep the temperature at 25°C, add 250g of pyridine under nitrogen protection, stir mechanically for 20min, add 500g of triethylsilyl chloride, stir and react for 3h to obtain reaction solution a; (2) Add 10 kg of toluene to the reaction solution a, stir evenly, then add 101.9 g of a 20% sodium hydroxide aqueous solution, stir and react for 0.5 h until the system becomes neutral, to obtain a reaction solution b; ⑶ Add 204 g of anhydrous sodium sulfate to the reaction solution b, stir and dry for 24 h, and filter to obtain a reaction solution c; (4) The reaction solution c was distilled under reduced pressure at 150°C for 5 h to obtain terminal triethyl fluorosilicone oil with a viscosity of 59500 mPa•s.

[0053] Comparative Example 1 Comparative Example 1: A vinyl-terminated fluorosilicone oil was prepared by a conventional method, and the specific steps are as follows: ⑴ Pour 10kg of trifluoropropylcyclotrisiloxane and 2.5g of tetramethylammonium hydroxide into a 30L reactor, dehydrate under reduced pressure at 40℃ for 1h, then add 120g of tetramethyldivinyldisiloxane into the reactor, heat to 100℃ and react at constant temperature for 120min, then heat to 145℃ and react for 1h, heat to 180℃ and decompress for 5h to remove low boiling points, and obtain vinyl-terminated fluorosilicone oil with a viscosity of 15000 mPa•s.

[0054] Figure 8 The vinyl-terminated fluorosilicone oil prepared in Comparative Example 1 is 1 HNMR spectrum, by Figure 8It can be seen that the silicone oil has an obvious Si-OH peak. This is because the end-capping agent tetramethyldivinyldisiloxane is more difficult to break than trifluoropropylcyclotrisiloxane and polyfluorosiloxane chains. Therefore, under the reaction conditions, the polymer chain will continue to break to form free radicals. After the polymerization reaction is completed, these free radicals will be converted into Si-OH, resulting in low vinyl end-capping efficiency of the product.

[0055] Comparative Example 2 ⑴ Pour 10kg 2000mPa•s terminal hydroxyl fluorosilicone oil into a 30L reactor, keep the temperature at 50°C, add 50g pyridine under nitrogen protection, stir mechanically for 20min, add 300g trimethylsilyl chloride, stir and react for 18h to obtain reaction solution a; (2) Add 2000 g of water to the reaction solution a, wash with water and stir for 1 hour, then pour out the acid solution, repeat the above washing operation 8 times until the system is neutral, and obtain reaction solution b; ⑶ Dehydrate the reaction solution b at 50°C under reduced pressure for 1 h, then heat to 150°C and distill under reduced pressure for 4 h to obtain terminal methyl fluorosilicone oil with a viscosity of 1960 mPa•s.

[0056] The difference between Comparative Example 2 and Example 6 is that step (2) uses water washing to remove the acid remaining in the polymer instead of using the alkali solution neutralization method in Example 6. The silicone oil obtained by this process is still well capped, but a large amount of wastewater is generated in the process, which is not suitable for green production.

[0057] Comparative Example 3 ⑴ Pour 10kg 30000mPa•s terminal hydroxyl fluorosilicone oil into a 30L reactor, keep the temperature at 60°C, add 20g triethylamine under nitrogen protection, stir mechanically for 30min, add 70g dimethylvinylchlorosilane, stir and react for 2h to obtain reaction solution a; (2) Add 500 g of tetrahydrofuran to the reaction solution a, stir evenly, then add 200 g of a 10% sodium bicarbonate aqueous solution, stir and react for 1 h until the system becomes neutral, to obtain a reaction solution b; ⑶ Distill the reaction solution b under reduced pressure at 50° C. to remove tetrahydrofuran and water in the system to obtain reaction solution c9; (4) Add 500 g of tetrahydrofuran to the reaction solution c, stir evenly, and filter to remove the salt in the system to obtain a reaction solution d; (5) The reaction liquid d was distilled under reduced pressure at room temperature for 2 h to recover 498 g of tetrahydrofuran, and then distilled under reduced pressure at 150°C for 5 h to obtain vinyl-terminated fluorosilicone oil with a viscosity of 26500 mPa•s.

[0058] In Comparative Example 3, water and organic solvents in the reaction system are removed by vacuum distillation, rather than the desiccant drying and water removal method used in the examples of the present application. For silicone oil with high viscosity, it is necessary to heat it again to reduce the viscosity or add an appropriate amount of solvent to reduce the viscosity during the filtration process to facilitate filtration, and the process is cumbersome.

[0059] The above is only the embodiment of the present application, and the protection scope of the present application is not limited by these specific embodiments, but is determined by the claims of the present application. For those skilled in the art, the present application can have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the technical ideas and principles of the present application should be included in the protection scope of the present application.

Claims

1. A method for preparing a terminal carbon functionalized polysiloxane, characterized in that: The following steps are involved: (1) After mixing terminal hydroxyl polysiloxane, chlorosilane and an acid binding agent, stirring and reacting under nitrogen protection to obtain a reaction solution a; (2) Add an organic solvent to the reaction solution a, stir evenly, add an alkali solution, stir and react until the system becomes neutral, and obtain a reaction solution b; (3) Add a desiccant to the reaction solution b, stir to dry, and filter to obtain a reaction solution c; (4) subjecting the reaction solution c to reduced pressure distillation to recover the solvent and obtain terminal carbon functionalized polysiloxane; The structural formula of the chlorosilane is shown in formula (1), Formula (1), Among them, R3, R4, and R5 are selected from one or more of methyl, ethyl, propyl, butyl, vinyl, allyl, phenyl, hydrogen, chloromethyl, chloropropyl, trifluoropropyl, and perfluorooctyl, and R3, R4, and R5 can be the same or different.

2. The method for preparing a terminal carbon functionalized polysiloxane according to claim 1, characterized in that: The structural formula of the hydroxy-terminated polysiloxane is shown in formula (2), Formula (2), Wherein, m, n, x are the degree of polymerization, m≥0, n≥0, x≥0, 10≤(m+n+x)≤10000; R1 and R2 are selected from one or more of methyl, ethyl, phenyl, and trifluoropropyl, and R1 and R2 may be the same or different.

3. The method for preparing a terminal carbon functionalized polysiloxane according to claim 1, characterized in that: The acid binding agent is selected from one or more of pyridine, N,N-diisopropylethylamine, 4-dimethylaminopyridine, triethanolamine, tetrabutylammonium bromide, triethylamine, potassium carbonate, ammonium carbonate and sodium carbonate.

4. The method for preparing a terminal carbon functionalized polysiloxane according to claim 1, characterized in that: The organic solvent is selected from one or more of acetone, dichloromethane, dioxane, tetrahydrofuran, petroleum ether, cyclohexane, and toluene; the alkali solution is selected from one or more of ammonia water, sodium hydroxide aqueous solution, potassium hydroxide aqueous solution, sodium carbonate aqueous solution, and sodium bicarbonate aqueous solution.

5. The method for preparing a terminal carbon functionalized polysiloxane according to claim 1, characterized in that: The desiccant is selected from one or more of anhydrous calcium chloride, anhydrous magnesium sulfate, anhydrous potassium carbonate, anhydrous magnesium sulfate, anhydrous calcium sulfate, molecular sieves, and anhydrous sodium sulfate.

6. The method for preparing a terminal carbon functionalized polysiloxane according to claim 1, characterized in that: In step (1), the reaction temperature is 0°C to 100°C, the reaction time is 0.5h to 12h; the mass of the chlorosilane is 0.1% to 50% of the mass of the terminal hydroxyl polysiloxane; and the mass of the acid binding agent is 10% to 100% of the mass of the chlorosilane.

7. The method for preparing a terminal carbon functionalized polysiloxane according to claim 1, characterized in that: In step (2), the stirring reaction time is 0.5h~6h; the mass of the organic solution is 0%~1000% of the mass of the terminal hydroxyl polysiloxane; and the mass fraction of the alkali solution is 1%~50%.

8. The method for preparing a terminal carbon functionalized polysiloxane according to claim 1, characterized in that: In step (3), the stirring and drying time is 1 h to 24 h; the mass of the desiccant is 1% to 500% of the mass of the alkali solution; in step (4), the temperature of the reduced pressure distillation is 30° C. to 150° C., and the time is 1 h to 6 h.

9. A terminal carbon functionalized polysiloxane, characterized in that: The method is prepared according to any one of claims 1 to 8.

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