Methyl phenyl high-boiling silicone oil and preparation method thereof

Abstract

The invention relates to the technical field of silicone oil production, in particular to methyl phenyl high-boiling silicone oil and a preparation method thereof. The preparation method is used for solving the technical problem that in the prior art, the stability, the oxidation resistance and the antibacterial property of the methyl phenyl high-boiling silicone oil are not further improved by adding proper auxiliaries and improving the process. The preparation method comprises the following steps: by taking a methyl phenyl dichlorosilane high-boiling-point substance and a diphenyl dichlorosilane high-boiling-point substance as raw materials, adding a high-stability antibacterial agent to prepare methyl phenyl high-boiling-point silicone oil; the hydrolysis accelerant is added to promote the rearrangement reaction in the hydrolysis process of the high-boiling-point substance raw material, and a connecting ring of a polymer is destroyed through the chain terminator, so that the phenomena of gelling and curing do not occur in the subsequent copolymerization equilibrium reaction; calcium carbonate nanoparticles are used as a carrier, so that the calcium carbonate nanoparticles can exert oxidation resistance and antibacterial ability in the methyl phenyl high-boiling silicone oil for a long time, and the prepared methyl phenyl high-boiling silicone oil has more excellent stability and oxidation resistance and has a certain antibacterial effect.

Description

Technical Field

[0001] The invention relates to the technical field of silicone oil production, and in particular to a methylphenyl high-boiling silicone oil and a preparation method thereof. Background Art

[0002] In the production process of organosilicon monomers, in addition to the main product dimethyldichlorosilane, byproducts such as monomethyltrichlorosilane, trimethylmonochlorosilane, low-boiling substances and high-boiling substances are also generated. The high-boiling substances of organosilicon have complex components and high chlorine content, so how to deal with high-boiling substances has become one of the bottlenecks affecting the sustainable development of the organosilicon industry.

[0003] Silicone oil usually refers to linear polysiloxane products that remain in liquid state at room temperature. Methylphenyl silicone oil is a product in which part of the methyl group of methyl silicone oil is replaced by phenyl. Due to the introduction of phenyl into the molecular chain, methylphenyl silicone oil has a higher viscosity coefficient, heat resistance, stability and insulation compared to ordinary methyl silicone oil, so it has broad development prospects in the fields of cosmetics, electronics, lubricants, aerospace, etc.

[0004] The patent with the authorization announcement number CN111978544B discloses a method for synthesizing methylphenyl high-boiling silicone oil, which uses methylphenyl dichlorosilane high-boiling products and diphenyl dichlorosilane high-boiling products as raw materials, first reacts with alcohol-water solvent, then adds catalyst tetramethylammonium hydroxide, octamethylcyclotetrasiloxane and chain terminator, and prepares methylphenyl high-boiling silicone oil after catalytic equilibrium. The invention has a simple preparation process and high yield, and effectively solves the problem of low utilization rate of high-boiling products. However, it is found that in the existing method for preparing methylphenyl high-boiling silicone oil, after the high-boiling hydrolyzate is hydrolyzed, the trifunctional groups contained in the high-boiling hydrolyzate contact with the hydrochloric acid material layer located at the bottom liquid part, and then crosslink and solidify under the catalysis of hydrochloric acid, and naturally form a polymer with a network structure, so that the methylphenyl high-boiling silicone oil is easy to deposit and adhere to the reaction vessel, which is easy to cause the reaction vessel to be blocked, affecting the production efficiency; and the method does not further improve the stability, antioxidant and antibacterial properties of the methylphenyl high-boiling silicone oil by adding suitable additives and improving the process. Summary of the invention

[0005] The object of the present invention is to provide a methylphenyl high-boiling silicone oil and a preparation method thereof, so as to solve the technical problem that the prior art has not further improved the stability, antioxidant and antibacterial properties of the methylphenyl high-boiling silicone oil by adding suitable additives and improving the process.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] A method for preparing methylphenyl high-boiling silicone oil comprises the following steps:

[0008] S1. Add high boiling products of methylphenyldichlorosilane and diphenyldichlorosilane into a reaction kettle, add a hydrolysis accelerator and a first chain terminator and stir continuously, dropwise add methanol aqueous solution at room temperature, and after the dropwise addition is completed, react at a constant temperature of 70 to 90° C. for 0.5 to 4 hours;

[0009] S2, cooling the reaction solution and allowing it to stand for stratification, collecting the oil layer, washing it with water until it is neutral, and then distilling it to obtain a high-boiling hydrolysis crude product;

[0010] S3, placing the high-boiling hydrolysis crude product in a reaction kettle, adding tetramethylammonium hydroxide, octamethylcyclotetrasiloxane and a second chain terminator under stirring, and reacting at 60-130° C. under vacuum conditions for 0.5-3 h;

[0011] S4. After the reaction is completed, heating is performed under normal pressure to remove tetramethylammonium hydroxide to obtain a refined reaction solution;

[0012] S5. After the refined reaction liquid is cooled to room temperature, a highly stable antibacterial auxiliary agent is added and stirred to obtain methylphenyl high-boiling silicone oil.

[0013] Preferably, the preparation method of the highly stable antibacterial auxiliary agent comprises the following steps:

[0014] S11, preparing 2,5-dioctylhydroquinone ferulate, calcium chloride and sodium carbonate into acetone aqueous solutions respectively;

[0015] S12, at a constant temperature, mixing calcium chloride and an acetone aqueous solution of 2,5-dioctylhydroquinone ferulate, stirring to obtain a mixed solution A, quickly adding a sodium carbonate solution to the mixed solution A, stirring to react, and obtaining a reaction solution B;

[0016] S13, centrifugally filtering the reaction solution B to collect the nanoparticle-like highly stable antibacterial auxiliary agent.

[0017] Preferably, the mass ratio of acetone to water in the acetone aqueous solution of 2,5-dioctylhydroquinone ferulate, calcium chloride and sodium carbonate in S11 is 3:(1-1.5); the molar concentration ratio of 2,5-dioctylhydroquinone ferulate, calcium chloride and sodium carbonate is (0.2-0.6):1:1.

[0018] Preferably, the constant temperature range in S12 is between 30 and 50° C., the dosage ratio of calcium chloride, 2,5-dioctylhydroquinone ferulate solution and sodium carbonate solution is 1:1:1, the calcium chloride solution and 2,5-dioctylhydroquinone ferulate solution are mixed and stirred with a magnetic stirrer for 10 to 20 minutes, and after adding the sodium carbonate solution, the mixture is stirred at 30 to 50° C. and at a speed of 400 to 1000 rpm for 5 to 15 minutes.

[0019] Preferably, in S13, centrifugal filtration is performed at a speed of 3000-10000 rpm for 2-3 times, and the obtained product is dried at a constant temperature of 30-50° C. in a vacuum and ground for 10-30 min.

[0020] Wherein, the synthetic reaction formula of 2,5-dioctyl hydroquinone ferulate is as follows:

[0021]

[0022] The synthetic method of 2,5-dioctyl hydroquinone ferulate comprises the following steps:

[0023] S21, stirring 2,5-dioctylhydroquinone and N,N-dimethylformamide to dissolve, and then adding dicyclohexylcarbodiimide and 4-dimethylaminopyridine;

[0024] S22, adding ferulic acid at low temperature to react, and after the reaction is complete, filtering to remove impurities to obtain a filtrate;

[0025] S23, washing the obtained filtrate with ice water and suction filtering, eluting the obtained crude product with a recrystallization solvent, and finally separating by column chromatography to obtain refined 2,5-dioctylhydroquinone ferulate.

[0026] Preferably, the usage ratio of 2,5-dioctylhydroquinone, N,N-dimethylformamide, dicyclohexylcarbodiimide and 4-dimethylaminopyridine in S21 is (0.1-0.3) mol: (1000-3000) mL: (0.2-0.6) mol: (0.01-0.02) mol.

[0027] Preferably, in S22, the molar ratio of ferulic acid to 2,5-dioctylhydroquinone is 2 to 3:1, and the reaction is carried out at a constant temperature of 0 to 10°C.

[0028] Preferably, in S23, the recrystallization solvent is ethyl acetate-petroleum ether, and the volume ratio of ethyl acetate to petroleum ether is 1:15-25.

[0029] Preferably, the mass ratio of the methylphenyl high boiling point substance to the diphenyldichlorosilane high boiling point substance in S1 is 1:0.5-2.5.

[0030] Preferably, the hydrolysis accelerator in S1 is one or more of coconut oil diethanolamide, lauroamphodiacetate disodium, cocoamidopropyl dimethylglycine and hexadecyl sulfobetaine, and the added amount thereof is 0.05-1wt% of the sum of the mass of methylphenyldichlorosilane high boiling products and diphenyldichlorosilane high boiling products.

[0031] Preferably, the first chain terminator and the second chain terminator in S1 and S3 are one or more of tetramethyldiphenyldisiloxane, dimethyltetraphenyldisiloxane, divinyltetramethyldisiloxane and hexamethyldisiloxane.

[0032] Preferably, the mass ratio of methanol to water in the methanol aqueous solution in S1 is 1:0.05-1, and the amount of methanol aqueous solution added is 30-60 wt % of the sum of the masses of high boiling methylphenyldichlorosilane and high boiling diphenyldichlorosilane.

[0033] Preferably, the amount of the chain terminator added in S1 is 0.05-0.1 wt % of the sum of the masses of the high boiling products of methylphenyldichlorosilane and diphenyldichlorosilane.

[0034] Preferably, the temperature in S2 is controlled at 70 to 120° C. under reduced pressure of -0.08 to -0.1 MPa to remove water and low boiling substances by distillation.

[0035] Preferably, the amount of tetramethylammonium hydroxide added in S3 is 0.003-0.008 wt % of the sum of the masses of the high boiling products of methylphenyldichlorosilane and diphenyldichlorosilane.

[0036] Preferably, the amount of octamethylcyclotetrasiloxane added in S3 is 2-20 wt % of the sum of the mass of the high boiling products of methylphenyldichlorosilane and diphenyldichlorosilane.

[0037] Preferably, the amount of the second chain terminator added in S3 is 5 to 20 wt % of the sum of the mass of the high boiling products of methylphenyldichlorosilane and diphenyldichlorosilane.

[0038] Preferably, the S4 is heated to 140-170° C. and kept warm for 1-3 hours, and nitrogen is continuously introduced to remove waste gas in time.

[0039] Preferably, the amount of the highly stable antibacterial auxiliary agent added in S5 is 0.1-1 wt % of the mass of the refined reaction liquid.

[0040] The present invention also provides a methylphenyl high-boiling silicone oil prepared according to the preparation method of the methylphenyl high-boiling silicone oil.

[0041] The present invention has the following beneficial effects:

[0042] 1. The invention uses methylphenyldichlorosilane high boiling products and diphenyldichlorosilane high boiling products as raw materials, adds a hydrolysis promoter and a first chain terminator, drips a methanol aqueous solution for hydrolysis, adds tetramethylammonium hydroxide, octamethylcyclotetrasiloxane and a second chain terminator to the hydrolyzate for copolymerization equilibrium, and finally adds a high-stability antibacterial agent to prepare methylphenyl high boiling silicone oil; the addition of the hydrolysis promoter and the first chain terminator not only accelerates the hydrolysis rate of the high boiling product raw materials, but also reduces the problem of gelation and solidification of the trifunctional groups contained in the high boiling products under the catalysis of hydrochloric acid after contacting the hydrochloric acid material layer located at the bottom liquid part; the nanoparticles of 2,5-dioctylhydroquinone ferulate wrapped with calcium carbonate are added as the high-stability antibacterial auxiliary agent, so that the prepared methylphenyl high boiling silicone oil product is clearer and more transparent, has stronger stability and antioxidant properties, and significantly improves the antibacterial ability.

[0043] 2. The addition of the hydrolysis promoter of the present invention promotes the rearrangement reaction during the hydrolysis of the high-boiling raw material, reduces the trifunctional groups contained in the high-boiling raw material, and destroys the connecting ring of the polymer through the chain terminator, so that the polysiloxane tends to be more linearly arranged, so that the methylphenyl high-boiling silicone oil prepared by the subsequent copolymerization equilibrium reaction will not gel and solidify.

[0044] 3. The highly stable antibacterial adjuvant in the present invention has different physical and chemical properties from ordinary calcium carbonate due to the change of the crystal structure and surface electronic structure of the nanoparticles due to the size of the nanoparticles being close to the wavelength of light. The nanoparticles of 2,5-dioctylhydroquinone ferulate wrapped with calcium carbonate are used as highly stable antibacterial adjuvants, which can not only exert their antioxidant function, but also adjust the transparency and viscosity of the product by adjusting the size of the added nanoparticles.

[0045] 4. The effective ingredient of the highly stable antibacterial adjuvant in the present invention is 2,5-dioctylhydroquinone ferulate; 2,5-dioctylhydroquinone is a phenolic highly stable antibacterial adjuvant with excellent performance. The 2,5-dioctylhydroquinone ferulate prepared from 2,5-dioctylhydroquinone and ferulic acid not only has the antibacterial property of ferulic acid, but also its larger ortho-substituted group destroys the conjugation between the benzene ring and the phenolic hydroxyl oxygen, weakens the hydrogen-oxygen bond of the phenolic hydroxyl, and the free radical formed after the hydrogen leaves tends to be stable, so that its antioxidant property is improved. Calcium carbonate nanoparticles are used as carriers to enable it to exert its antioxidant and antibacterial abilities in methylphenyl high-boiling silicone oil for a long time, so that the prepared methylphenyl high-boiling silicone oil has more excellent stability and antioxidant property, and has a certain antibacterial effect. DETAILED DESCRIPTION

[0046] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] Example 1

[0048] A method for preparing a methylphenyl high-boiling silicone oil of the present embodiment comprises the following steps:

[0049] S1, add 500g and 250g of high-boiling methylphenyldichlorosilane and high-boiling diphenyldichlorosilane into a reactor, add 7.5g of hydrolysis promoter coconut oil diethanolamide and 0.75g of first chain terminator tetramethyldiphenyldichlorosilane and keep stirring, add 450g of methanol aqueous solution with a methanol and water mass ratio of 1:0.05 at room temperature, and after the addition of methanol aqueous solution is completed, react at 70°C for 4h at a constant temperature;

[0050] S2, cooling the reaction solution and allowing it to stand for stratification, collecting the oil layer and washing it with water until it is neutral, and then controlling the temperature to 70° C. under a reduced pressure of -0.08 MPa to distill off water and low-boiling substances to obtain a high-boiling hydrolysis crude product;

[0051] S3, placing the high-boiling hydrolysis crude product in a reaction kettle, adding 0.0225 g of tetramethylammonium hydroxide, 15 g of octamethylcyclotetrasiloxane and 37.5 g of the second chain terminator tetramethyldiphenyldichlorosilane under stirring, and reacting at 60° C. under vacuum conditions for 3 h;

[0052] S4. After the reaction is completed, the mixture is heated to 140°C under normal pressure and kept warm for 1 hour, and nitrogen is continuously introduced to remove waste gas in time to obtain a refined reaction liquid;

[0053] S5. After the refined reaction liquid is cooled to room temperature, 0.75 g of a highly stable antibacterial auxiliary agent is added and stirred to obtain methylphenyl high-boiling silicone oil.

[0054] The preparation method of the highly stable antibacterial auxiliary agent comprises the following steps:

[0055] S11, dissolving 6.87 g of 2,5-dioctyl hydroquinone ferulate, 5.55 g of calcium chloride, and 5.3 g of sodium carbonate into 100 mL of acetone aqueous solution having a mass ratio of acetone to water of 3:1, respectively, to prepare 2,5-dioctyl hydroquinone ferulate acetone aqueous solution, calcium chloride acetone aqueous solution, and sodium carbonate acetone aqueous solution;

[0056] S12, at a constant temperature of 30° C., mixing calcium chloride and an acetone aqueous solution of 2,5-dioctylhydroquinone ferulate, stirring for 5 min to obtain a mixed solution A, rapidly adding a sodium carbonate solution to the mixed solution A, stirring at a speed of 400 rpm for 5 min to obtain a reaction solution B, wherein the amounts of calcium chloride, 2,5-dioctylhydroquinone ferulate solution and sodium carbonate solution are 100 mL, 100 mL and 100 mL respectively;

[0057] S13, centrifugally filter the reaction solution B at a speed of 3000 rpm for 3 times, dry the obtained product at a constant temperature of 30° C. in a vacuum, grind for 10 min, and collect the nano-particles to obtain a highly stable antibacterial auxiliary agent.

[0058] The synthetic method of 2,5-dioctyl hydroquinone ferulate comprises the following steps:

[0059] S21, 5.58 g of 2,5-dioctylhydroquinone and 500 mL of N,N-dimethylformamide were stirred to dissolve, and then 6.88 g of dicyclohexylcarbodiimide and 0.407 g of 4-dimethylaminopyridine were added;

[0060] S22, adding 6.47 g of ferulic acid at a constant temperature of 0° C. to react, and after the reaction is complete, filtering to remove impurities to obtain a filtrate;

[0061] S23. The obtained filtrate is rinsed and filtered with ice water, and the obtained crude product is eluted with a recrystallization solvent, the recrystallization solvent is ethyl acetate-petroleum ether, and the volume ratio of ethyl acetate to petroleum ether is 1:15. Finally, column chromatography is used to separate and obtain refined 2,5-dioctylhydroquinone ferulate.

[0062] Example 2

[0063] A method for preparing a methylphenyl high-boiling silicone oil of the present embodiment comprises the following steps:

[0064] S1, add 200g and 500g of high-boiling methylphenyldichlorosilane and high-boiling diphenyldichlorosilane into a reactor, add 0.35g of hydrolysis promoter coconut oil diethanolamide and 0.35g of first chain terminator tetramethyldiphenyldichlorosilane and keep stirring, add 210g of methanol aqueous solution with a methanol and water mass ratio of 1:1 at room temperature, and after the addition of methanol aqueous solution is completed, react at a constant temperature of 90°C for 0.5h;

[0065] S2, cooling the reaction solution and allowing it to stand for stratification, collecting the oil layer and washing it with water until it is neutral, and then controlling the temperature at 120° C. under a reduced pressure of -0.1 MPa to distill off water and low-boiling substances to obtain a high-boiling hydrolysis crude product;

[0066] S3, placing the high-boiling hydrolysis crude product in a reaction kettle, adding 0.056 g of tetramethylammonium hydroxide, 140 g of octamethylcyclotetrasiloxane and 140 g of the second chain terminator tetramethyldiphenyldichlorosilane under stirring, and reacting at 130° C. under vacuum conditions for 3 hours;

[0067] S4. After the reaction is completed, the mixture is heated to 170°C under normal pressure and kept warm for 3 hours, and nitrogen is continuously introduced to remove waste gas in time to obtain a refined reaction liquid;

[0068] S5. After the refined reaction liquid is cooled to room temperature, 7 g of a highly stable antibacterial auxiliary agent is added and stirred to obtain methylphenyl high-boiling silicone oil.

[0069] The method for preparing the highly stable antibacterial auxiliary agent comprises the following steps:

[0070] S11, dissolving 10.3 g of 2,5-dioctyl hydroquinone ferulate, 2.78 g of calcium chloride, and 2.65 g of sodium carbonate into 100 mL of acetone aqueous solution with a mass ratio of acetone to water of 2:1, respectively, to prepare 2,5-dioctyl hydroquinone ferulate acetone aqueous solution, calcium chloride acetone aqueous solution, and sodium carbonate acetone aqueous solution;

[0071] S12, at a constant temperature of 50° C., mixing calcium chloride and an acetone aqueous solution of 2,5-dioctylhydroquinone ferulate, stirring for 15 min to obtain a mixed solution A, rapidly adding a sodium carbonate solution to the mixed solution A, stirring at a speed of 1000 rpm for 15 min to obtain a reaction solution B, wherein the amounts of calcium chloride, 2,5-dioctylhydroquinone ferulate solution and sodium carbonate solution are 100 mL, 100 mL and 100 mL respectively;

[0072] S13, centrifugally filter the reaction solution B at a speed of 10000 rpm for 2 to 3 times, dry the obtained product at a constant temperature of 50° C. in a vacuum, grind for 30 minutes, and collect the nano-particles to obtain a highly stable antibacterial auxiliary agent.

[0073] The synthetic method of 2,5-dioctyl hydroquinone ferulate comprises the following steps:

[0074] S21, 10.04 g of 2,5-dioctylhydroquinone and 100 mL of N,N-dimethylformamide were stirred to dissolve, and then 12.38 g of dicyclohexylcarbodiimide and 0.733 g of 4-dimethylaminopyridine were added;

[0075] S22, adding 17.48 g of ferulic acid at a constant temperature of 10° C. to react, and after the reaction is complete, filtering to remove impurities to obtain a filtrate;

[0076] S23. The obtained filtrate is rinsed and filtered with ice water, and the obtained crude product is eluted with a recrystallization solvent, wherein the recrystallization solvent is ethyl acetate-petroleum ether, and the volume ratio of ethyl acetate to petroleum ether is 1:25. Finally, column chromatography is used to separate and obtain refined 2,5-dioctylhydroquinone ferulate.

[0077] Example 3

[0078] A method for preparing a methylphenyl high-boiling silicone oil of the present embodiment comprises the following steps:

[0079] S1, add 500g and 500g of high-boiling methylphenyldichlorosilane and high-boiling diphenyldichlorosilane into a reactor, add 5g of hydrolysis promoter coconut oil diethanolamide and 0.7g of first chain terminator tetramethyldiphenyldichlorosilane and keep stirring, add 500g of methanol aqueous solution with a methanol and water mass ratio of 1:0.5 at room temperature, and after the addition of methanol aqueous solution is completed, react at a constant temperature of 80°C for 2.5h;

[0080] S2, cooling the reaction solution and allowing it to stand for stratification, collecting the oil layer and washing it with water until it is neutral, and then controlling the temperature to 90° C. under a reduced pressure of -0.1 MPa to distill off water and low-boiling substances to obtain a high-boiling hydrolysis crude product;

[0081] S3, placing the high-boiling hydrolysis crude product in a reaction kettle, adding 0.05 g of tetramethylammonium hydroxide, 100 g of octamethylcyclotetrasiloxane and 100 g of the second chain terminator tetramethyldiphenyldichlorosilane under stirring, and reacting at 110° C. under vacuum conditions for 2 h;

[0082] S4. After the reaction is completed, the mixture is heated to 120°C under normal pressure and kept warm for 2 hours, and nitrogen is continuously introduced to remove waste gas in time to obtain a refined reaction liquid;

[0083] S5. After the refined reaction liquid is cooled to room temperature, 5 g of a highly stable antibacterial auxiliary agent is added and stirred to obtain methylphenyl high-boiling silicone oil.

[0084] Preferably, the preparation method of the highly stable antibacterial auxiliary agent comprises the following steps:

[0085] S11, dissolving 13.73 g of 2,5-dioctyl hydroquinone ferulate, 5.55 g of calcium chloride, and 5.3 g of sodium carbonate respectively into 100 mL of acetone aqueous solution in which the mass ratio of acetone to water is 2.5:1, to prepare 2,5-dioctyl hydroquinone ferulate acetone aqueous solution, calcium chloride acetone aqueous solution, and sodium carbonate acetone aqueous solution;

[0086] S12, at a constant temperature of 40° C., mixing calcium chloride and an acetone aqueous solution of 2,5-dioctylhydroquinone ferulate, stirring for 15 min to obtain a mixed solution A, rapidly adding a sodium carbonate solution to the mixed solution A, stirring at a speed of 600 rpm for 10 min to obtain a reaction solution B, wherein the amount ratio of calcium chloride, 2,5-dioctylhydroquinone ferulate solution and sodium carbonate solution is 100 mL: 100 mL: 100 mL;

[0087] S13, centrifugally filter the reaction solution B at a speed of 5000 rpm for 2 to 3 times, dry the obtained product at a constant temperature of 40° C. in a vacuum, grind for 20 minutes, and collect to obtain a nano-particle-shaped highly stable antibacterial auxiliary agent. Preferably, the synthesis method of 2,5-dioctylhydroquinone ferulate comprises the following steps:

[0088] S21, after 6.7 g of 2,5-dioctylhydroquinone and 400 mL of N,N-dimethylformamide were stirred and dissolved, 8.26 g of dicyclohexylcarbodiimide and 0.488 g of 4-dimethylaminopyridine were added, and the amount ratio of 2,5-dioctylhydroquinone, N,N-dimethylformamide, dicyclohexylcarbodiimide and 4-dimethylaminopyridine was 0.1 mol: 2000 mL: 0.2 mol: 0.01 mol;

[0089] S22, adding 9.71 g of ferulic acid at a constant temperature of 5° C. to react, and after the reaction is complete, filtering to remove impurities to obtain a filtrate;

[0090] S23. The obtained filtrate is rinsed and filtered with ice water, and the obtained crude product is eluted with a recrystallization solvent, wherein the recrystallization solvent is ethyl acetate-petroleum ether, and the volume ratio of ethyl acetate to petroleum ether is 1:20. Finally, column chromatography is used to separate and obtain refined 2,5-dioctylhydroquinone ferulate.

[0091] Comparative Example 1

[0092] The difference between this comparative example and Example 1 is that the masses of high-boiling methylphenyldichlorosilane and high-boiling diphenyldichlorosilane are changed to 500 g and 10 g, no hydrolysis accelerator and first chain terminator are added, the mass of methanol aqueous solution added dropwise is changed to 50 g, and the reaction time is changed to 6 h.

[0093] Comparative Example 2

[0094] The difference between this comparative example and Example 1 is that the amount of the highly stable antibacterial auxiliary agent is increased to 75 g.

[0095] Comparative Example 3

[0096] The difference between this comparative example and Example 2 is that after the sodium carbonate solution is quickly added to the calcium chloride solution, the reaction is stirred at a speed of 600 rpm for 10 minutes to obtain a reaction solution B, and then the hydroquinone ferulate solution is added to the reaction solution B.

[0097] Comparative Example 4

[0098] The difference between this comparative example and Example 2 is that 2,5-dioctylhydroquinone ferulate is replaced by hydroquinone diacetate.

[0099] Physical properties test

[0100] The properties of the methylphenyl high boiling silicone oils obtained in Examples 1 to 3 and Comparative Examples 1 to 4 were observed, the volatile content of the obtained samples at 150° C. was tested, and the viscosity was measured using an Ostwald viscometer at room temperature.

[0101] Antimicrobial testing

[0102] Escherichia coli was used as the test strain, the culture medium was heated and melted, and then the sample was added. After the test strain was added to the obtained culture medium, it was sealed and placed in a biochemical incubator for incubation at 18°C ​​for 96 hours and observed. The culture medium without sample addition was used to culture the strain in the same mode as the control group to test the antibacterial rate of the sample.

[0103]

[0104] A is the average number of recovered bacteria in the control group, and B is the average number of recovered bacteria after adding the sample.

[0105] The test results are shown in the following table:

[0106]

[0107]

[0108] As can be seen from the above table, the methylphenyl high-boiling silicone oils prepared in Examples 1 to 3 are clear and transparent, and their volatile content meets the requirements of high-boiling silicone oil for volatiles (<10%), and the antibacterial rate is above 90%, which has excellent antibacterial ability; the sample prepared in Comparative Example 1 is a turbid oily substance. Compared with Example 1, its volatile content increases, the viscosity increases, and the antibacterial rate decreases. The reason is that the high-boiling substance fails to react fully, and the colloid substance formed not only hinders the removal of impurities, but also provides space for the growth of bacteria; Comparative Example 2 adds too much high-stable antibacterial additives, although the antibacterial performance and viscosity are compared with Example 1 The results show that the antibacterial rate of comparative example 3 is significantly reduced compared with that of example 2, because the nanoparticles in the prepared highly stable antibacterial auxiliary agent do not encapsulate the effective ingredients of the auxiliary agent, which greatly shortens the shelf life of the effective ingredients and reduces the antibacterial performance; the auxiliary agent components added in comparative example 4 are different, among which hydroquinone diacetate is liquid at 150°C and may escape nanoparticles, causing the volatile content of the sample to increase and the viscosity to decrease, and hydroquinone diacetate does not have the functional group corresponding to 2,5-dioctylhydroquinone ferulate, and the antibacterial ability of the sample is greatly reduced.

[0109] The above is only a preferred specific implementation method of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solution and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

[0110] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing methylphenyl high-boiling silicone oil, characterized in that: The following steps are involved: S1. Place high boiling products of methylphenyldichlorosilane and diphenyldichlorosilane in a reaction kettle, add a hydrolysis accelerator and a first chain terminator, dropwise add a methanol aqueous solution at room temperature, and stir continuously. After the dropwise addition is completed, react at a constant temperature of 70 to 90° C. for 0.5 to 4 hours; S2, cooling the reaction solution and allowing it to stand for stratification, collecting the oil layer, washing it with water until it is neutral, and then distilling it to obtain a high-boiling hydrolyzate; S3, placing the high-boiling hydrolyzate in a reaction kettle, stirring continuously, adding tetramethylammonium hydroxide, octamethylcyclotetrasiloxane and a second chain terminator, and reacting under vacuum conditions at 60-130° C. for 0.5-3 h; S4. After the reaction is completed, heating is performed under normal pressure to remove tetramethylammonium hydroxide to obtain a refined reaction solution; S5. After the refined reaction liquid is cooled to room temperature, a highly stable antibacterial auxiliary agent is added and stirred to obtain methylphenyl high-boiling silicone oil; the highly stable antibacterial auxiliary agent is nanoparticles of 2,5-dioctylhydroquinone ferulate coated with calcium carbonate.

2. The method for preparing a methylphenyl high boiling silicone oil according to claim 1, characterized in that: The preparation method of the highly stable antibacterial auxiliary agent comprises the following steps: S11, preparing 2,5-dioctylhydroquinone ferulate, calcium chloride and sodium carbonate into acetone aqueous solutions respectively; S12, at a constant temperature, mixing calcium chloride and an acetone aqueous solution of 2,5-dioctylhydroquinone ferulate, stirring to obtain a mixed solution A, quickly adding a sodium carbonate solution to the mixed solution A, stirring to react, and obtaining a reaction solution B; S13, centrifugally filtering the reaction solution B to collect the nanoparticle-like highly stable antibacterial auxiliary agent.

3. The method for preparing a methylphenyl high boiling silicone oil according to claim 2, characterized in that: In the S11, the mass ratio of acetone to water in the acetone aqueous solution of 2,5-dioctyl hydroquinone ferulate, calcium chloride and sodium carbonate is 3:(1-1.5), and the molar concentration ratio of 2,5-dioctyl hydroquinone ferulate, calcium chloride and sodium carbonate is (0.2-0.6):1:1; in the S12, the constant temperature range is between 30 and 50°C, the calcium chloride and 2,5-dioctyl hydroquinone ferulate solution is stirred with a magnetic stirrer for 10 to 20 minutes, and after the sodium carbonate solution is added, it is stirred at a speed of 400 to 1000 rpm at 30 to 50°C for 5 to 15 minutes; in the S13, centrifugal filtration is performed at a speed of 3000 to 10000 rpm for 2 to 3 times, and the obtained product is dried at a constant temperature of 30 to 50°C in a vacuum and ground for 10 to 30 minutes.

4. The method for preparing a methylphenyl high boiling silicone oil according to claim 2, characterized in that: The preparation method of 2,5-dioctyl hydroquinone ferulate comprises the following steps: S21, stirring 2,5-dioctylhydroquinone and N,N-dimethylformamide to dissolve, and then adding dicyclohexylcarbodiimide and 4-dimethylaminopyridine; S22, adding ferulic acid at low temperature to react, and after the reaction is complete, filtering to remove impurities to obtain a filtrate; S23, washing the obtained filtrate with ice water and suction filtering, eluting the obtained crude product with a recrystallization solvent, and finally separating by column chromatography to obtain refined 2,5-dioctylhydroquinone ferulate.

5. The method for preparing a methylphenyl high boiling silicone oil according to claim 4, characterized in that: In S21, the dosage ratio of 2,5-dioctylhydroquinone, N,N-dimethylformamide, dicyclohexylcarbodiimide and 4-dimethylaminopyridine is (0.1-0.3) mol: (1000-3000) mL: (0.2-0.6) mol: (0.002-0.004) mol; in S22, the molar ratio of ferulic acid to 2,5-dioctylhydroquinone is 2-3:1, and the reaction is carried out at a constant temperature of 0-10°C; in S23, the recrystallization solvent is ethyl acetate-petroleum ether, and the volume ratio of ethyl acetate to petroleum ether is 1:15-25.

6. The method for preparing a methylphenyl high boiling silicone oil according to claim 1, characterized in that: In the S1, the mass ratio of high boiling methylphenyldichlorosilane to high boiling diphenyldichlorosilane is 1:0.5-2.5, the mass ratio of methanol to water in the methanol aqueous solution is 1:0.05-1, and the amount of methanol aqueous solution added is 30-60wt% of the sum of the mass of high boiling methylphenyldichlorosilane and high boiling diphenyldichlorosilane.

7. The method for preparing a methylphenyl high boiling silicone oil according to claim 1, characterized in that: The first chain terminator and the second chain terminator in S1 and S3 are one or more of tetramethyldiphenyldisiloxane, dimethyltetraphenyldisiloxane, divinyltetramethyldisiloxane and hexamethyldisiloxane, and the amount of the first chain terminator added is 0.05-0.1wt% of the sum of the mass of the high boiling products of methylphenyldichlorosilane and diphenyldichlorosilane.

8. The method for preparing a methylphenyl high boiling silicone oil according to claim 1, characterized in that: In the S2, the temperature is controlled at 70-120° C. under a reduced pressure of -0.08 to -0.1 MPa to remove water and low boiling substances by distillation; in the S3, the added amounts of tetramethylammonium hydroxide, octamethylcyclotetrasiloxane and the second chain terminator are 0.003-0.008 wt %, 2-20 wt % and 5-20 wt % of the sum of the masses of the high boiling substances of methylphenyldichlorosilane and diphenyldichlorosilane.

9. The method for preparing a methylphenyl high boiling silicone oil according to claim 1, characterized in that: In the step S4, the mixture is heated to 140-170° C. and kept warm for 1-3 hours, and nitrogen is continuously introduced to remove waste gas in time; in the step S5, the amount of the highly stable antibacterial auxiliary agent added is 0.1-1 wt % of the mass of the refined reaction liquid.

10. A methylphenyl high boiling point silicone oil prepared according to the method for preparing a methylphenyl high boiling point silicone oil according to any one of claims 1 to 9.

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