High-refraction phenyl silicone oil and preparation method thereof

Abstract

The invention discloses high-refraction phenyl silicone oil and a preparation method thereof, and relates to the technical field of organosilicone, the high-refraction phenyl silicone oil comprises the following raw materials: phenyl trichlorosilane, diphenyl dichlorosilane, methyl trichlorosilane, dimethyl dichlorosilane, hexamethyldisiloxane, a catalyst and a solvent; the preparation is performed based on the raw materials. According to the invention, by reasonably regulating and controlling the ratio of the phenyl trichlorosilane to the diphenyl dichlorosilane, premature crosslinking of the system is avoided while high refractive index is maintained; by introducing methyl trichlorosilane and dimethyl dichlorosilane, the flowability and viscosity are accurately adjusted, and the optical performance and the processability are both considered; and hexamethyldisiloxane is added in batches in the condensation stage to form a uniform end sealing structure, so that the high-refraction phenyl silicone oil with narrow molecular weight distribution and stable and controllable refractive index is obtained. The transparency and the thermal stability of the material are improved, and the bivariate accurate matching capability of the refractive index and the viscosity is remarkably improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of organosilicon, in particular to a high-refractive phenyl silicone oil and a preparation method thereof. BACKGROUND

[0002] The high-refractive phenyl silicone oil is generally obtained by co-hydrolysis and condensation of phenyltrichlorosilane, diphenyldichlorosilane, methyltrichlorosilane and dimethyldichlorosilane in the presence of a solvent, and then end-capped by hexamethyldisiloxane.

[0003] In the prior art, although the use of phenyltrichlorosilane and diphenyldichlorosilane can effectively increase the refractive index, when the content of phenyl is too high, side reactions or gelation are prone to occur during the hydrolysis and condensation stage, resulting in a wide molecular weight distribution of the finished product and a decrease in transparency.

[0004] On the other hand, although methyltrichlorosilane and dimethyldichlorosilane can improve the flowability and processability, when the proportion is not properly controlled, the refractive index is often decreased, and it is difficult to balance the optical performance and process stability.

[0005] In addition, hexamethyldisiloxane is often used as an end-capping agent in existing applications, but improper control of the feeding time and amount of hexamethyldisiloxane will cause insufficient or excessive end-capping, thereby affecting the long-term thermal stability and refractive index uniformity of the product.

[0006] In summary, the balance between the phenyl and methyl components and the synergistic optimization of the end-capping process are not perfect in the prior art, which limits the application of high-refractive phenyl silicone oil in the optical field. SUMMARY

[0007] In view of the deficiencies of the prior art, the present application provides a high-refractive phenyl silicone oil and a preparation method thereof to solve the problems raised in the background art.

[0008] To achieve the above-mentioned purposes, the present application provides the following technical solutions: The first object of the present application is to provide a preparation method of a high-refractive phenyl silicone oil, comprising the following specific steps: S1, formula weighing and solvent preloading: phenyltrichlorosilane, diphenyldichlorosilane, methyltrichlorosilane, dimethyldichlorosilane and solvent are added to a reaction kettle in proportion, and low-temperature preparation is carried out under nitrogen protection; S2, stepwise co-hydrolysis and heat release control: stepwise co-hydrolysis is carried out by adding water at 0-10℃, the H2O / chlorine equivalent ratio is controlled, and the process is completed in two stages, and the tail gas HCl is absorbed by alkali; S3, catalytic condensation and synchronous end-capping by hexamethyldisiloxane: the temperature is raised to 90-120℃, a catalyst is added, and condensation reaction is carried out, while hexamethyldisiloxane is added in batches for end-capping, and the molecular weight and viscosity are controlled; S4, deacidification and dehydration and low boiling point removal: after reaction, reduce pressure and heat to remove solvent and low boiling point, scan acid with nitrogen, add adsorbent to purify, control acid value and moisture in the specified range; S5, refractive index-molecular weight combined fine adjustment: maintain 120-130℃ for short-range rebalancing, regulate refractive index and viscosity, add hexamethyldisiloxane tail end seal to ensure performance accuracy; S6, polishing filtration, degassing and inspection filling: the material is polished and filtered and vacuum degassed, and after detection of refractive index, viscosity and acid value indicators are qualified, filling and packaging are completed under nitrogen protection; Among them, the phenyltrichlorosilane is 30-60 parts by weight, the diphenyldichlorosilane is 10-30 parts by weight, the methyltrichlorosilane is 5-15 parts by weight, the dimethyldichlorosilane is 15-35 parts by weight, the hexamethyldisiloxane is 1-5 parts by weight, the catalyst is 0.05-0.5 parts by weight, and the solvent is 10-50 parts by weight.

[0009] Further optimize the technical solution, the phenyltrichlorosilane, the specific preparation steps are as follows: In the corrosion-resistant reaction kettle, industrial silicon powder with an average particle size of 10-50 μm is added, a catalyst is added, dry hydrogen chloride gas is introduced at 280-320℃, and benzene is continuously added dropwise. The pressure is maintained at 0.2-0.4 MPa during the reaction, and the reaction time is 6-8 h. After the reaction is completed, the crude product is subjected to 80-120℃, 0.08 MPa reduced pressure distillation to remove low boiling point substances, and then separated by a fractionating column at 150-160℃ / 1.0 kPa, to obtain phenyltrichlorosilane with a purity of ≥99%.

[0010] Further optimize the technical solution, the catalyst used in the preparation of the phenyltrichlorosilane is a copper powder / zinc powder mixture, and the amount of the catalyst is controlled at 2-5 wt.% of the mass of the industrial silicon powder; the molar ratio of the benzene, industrial silicon powder and hydrogen chloride is 1.0:1.2:3.0; the dropwise addition rate of the benzene is controlled at 0.5-1.0 mL / min to avoid excessive generation of the byproduct diphenyldichlorosilane.

[0011] Further optimize the technical solution, the diphenyldichlorosilane, the specific preparation steps are as follows: In a three-necked flask, anhydrous magnesium turnings are added, and bromobenzene is slowly added dropwise at 0-5℃ under nitrogen protection. Anhydrous diethyl ether is added as a solvent during the dropwise addition process to generate a phenylmagnesium bromide reagent; After the solution is clarified, anhydrous diethyl ether solution of trichlorosilane is added, the system temperature is maintained at 10-15℃, and the molar ratio is controlled at PhMgBr:SiCl4=2.2:1.0; After the reaction is completed, the temperature is raised to 60°C and stirred at reflux for 4h, the reaction liquid is hydrolyzed, separated, and the organic layer is washed with 5wt.% NaHCO3 solution and saturated sodium chloride solution to remove acidic impurities. The crude product is dried with anhydrous magnesium sulfate, and then purified by distillation at a boiling point of 140-145°C / 0.5kPa under reduced pressure to obtain diphenyldichlorosilane with a purity of ≥98%.

[0012] Further optimization of the technical solution, the methyltrichlorosilane, the specific preparation steps are as follows: The metal silicon powder with an average particle size of 20-40μm is filled in the fixed bed reactor, and the catalyst is added. The reaction temperature is controlled at 280-300°C, and the pressure is maintained at 0.25-0.35MPa; The flow rate of methyl chloride gas is controlled at 0.5-1.5mol / (kg·h), and the reaction time is 8-10h. The crude product after reaction is collected by condensation, and then refined by distillation at 65-70°C / 10kPa to obtain methyltrichlorosilane with a purity of ≥99%.

[0013] Further optimization of the technical solution, the catalyst in the preparation of methyltrichlorosilane includes a main catalyst and a co-catalyst. The main catalyst is 2-3wt.% copper powder, and the co-catalyst is 0.5-1wt.% zinc powder.

[0014] Further optimization of the technical solution, the dimethyldichlorosilane, the specific preparation steps are as follows: The metal silicon powder and copper powder are uniformly mixed in a weight ratio of 20:1 and then loaded into a fluidized bed reactor. The reaction temperature is set to 290-310°C, and the reaction pressure is controlled at 0.3-0.5MPa; Methyl chloride gas is introduced, and the flow rate is controlled at 1.0-2.0mol / (kg·h), and the reaction is continued for 6-8h. After the crude product is separated, it is separated by distillation at 70-75°C / 8kPa to collect the fraction, thereby obtaining dimethyldichlorosilane with a purity of ≥98%.

[0015] Further optimization of the technical solution, the hexamethyldisiloxane, the specific preparation steps are as follows: In a stirred tank, trimethylchlorosilane is added, and deionized water is added dropwise while controlling the temperature at 0-5°C and maintaining nitrogen protection; During the hydrolysis process, trimethylsilanol and hydrogen chloride are generated. After the reaction is completed, 10wt.% NaOH solution is used to wash to remove residual HCl. The obtained trimethylsilanol is subjected to condensation reaction to generate hexamethyldisiloxane in the presence of an acidic catalyst at 60-70°C for 3-4h. The crude product is subjected to reduced pressure distillation at a boiling point of 100-105°C / 5kPa to obtain hexamethyldisiloxane with a purity of ≥99%.

[0016] Further optimize the technical scheme, the weight ratio of trimethylchlorosilane and deionized water is 2:1, the molar ratio is controlled to be 2.2:1.0, and the acidic catalyst is 0.1wt.% p-toluenesulfonic acid.

[0017] The second object of the present application is to provide a high-refractive phenyl silicone oil prepared by the preparation method of the high-refractive phenyl silicone oil.

[0018] Compared with the prior art, the present application provides a high-refractive phenyl silicone oil and a preparation method thereof, which has the following beneficial effects: The high-refractive phenyl silicone oil and the preparation method thereof of the present application can ensure high refractive index while avoiding premature crosslinking of the system by reasonably adjusting the ratio of phenyltrichlorosilane and diphenyldichlorosilane; the optical performance and processing performance are considered by introducing methyltrichlorosilane and dimethyldichlorosilane to accurately adjust the flowability and viscosity; and the uniform end-capped structure is formed by adding hexamethyldisiloxane in batches in the condensation stage, so that the high-refractive phenyl silicone oil with narrow molecular weight distribution, stable and controllable refractive index is obtained. The technical scheme not only improves the transparency and thermal stability of the material, but also significantly improves the accurate matching ability of the two variables of refractive index and viscosity, as a dilution component or a refractive index adjusting component, so that it is more suitable for application scenarios with strict requirements on optical performance, such as LED encapsulation glue, optical adhesive and high-transparency coating. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0020] Figure 1 The flowchart of the preparation method of the high-refractive phenyl silicone oil according to the present application is shown. DETAILED DESCRIPTION

[0021] In order to make the above-mentioned objects, features and advantages of the present application more apparent and easy to understand, the specific embodiments of the present application will be described in detail below with reference to the drawings.

[0022] In the following description, many specific details are set forth in order to provide a thorough understanding of the present application, but the present application can also be implemented in other ways different from the description, and those skilled in the art can make similar generalizations without departing from the scope of the present application, therefore the present application is not limited to the specific embodiments disclosed below.

[0023] Second, the "one embodiment" or "an embodiment" referred to herein can include, but is not limited to, any one of the specific features, structures, or characteristics individually or in any combination.

[0024] A high refractive phenyl silicone oil, comprising the following raw materials by weight: 30-60 parts of phenyltrichlorosilane as a main phenyl introduction monomer to provide high refractive phenyl substituents.

[0025] 10-30 parts of diphenyldichlorosilane to enhance the phenyl content, increase the refractive index and heat resistance.

[0026] 5-15 parts of methyltrichlorosilane to adjust the viscosity and flexibility, and prevent poor flowability caused by too high phenyl.

[0027] 15-35 parts of dimethyldichlorosilane to balance the refractive index and processability, and reduce the viscosity of the system.

[0028] 1-5 parts of hexamethyldisiloxane to end-cap, control the degree of polymerization and viscosity.

[0029] 0.05-0.5 parts of a catalyst (ferric chloride / tetrabutylammonium chloride / potassium aluminum sulfate, etc.) to control the rate of polycondensation reaction and ensure uniform molecular weight distribution.

[0030] 10-50 parts of a solvent, which can be recycled, can be toluene or dichloroethane.

[0031] The preparation steps of phenyltrichlorosilane are as follows: In a corrosion-resistant reaction kettle, 100 parts of industrial silicon powder with an average particle size of 10-50 μm are added, a copper / zinc powder mixture is used as a catalyst, and the amount of catalyst is controlled at 2-5 wt.% of the mass of the industrial silicon powder. Dry hydrogen chloride gas is introduced into the system at 280-320°C, and benzene is continuously added at a molar ratio of benzene:industrial silicon powder:hydrogen chloride = 1.0:1.2:3.0. The pressure is maintained at 0.2-0.4 MPa during the reaction, and the reaction time is about 6-8 h. By strictly controlling the drop rate of benzene (0.5-1.0 mL / min), the excessive generation of by-product diphenyldichlorosilane can be effectively avoided. After the reaction is completed, the crude product is subjected to vacuum distillation (80-120°C, 0.08 MPa) to remove low-boiling substances, and then separated by a fractionating column at 150-160°C / 1.0 kPa to obtain phenyltrichlorosilane with a purity of ≥99%. This method effectively improves the selectivity of the target product by optimizing the catalyst ratio and the order of feeding, and can be directly used as a monomer raw material for high-refractive silicone oil.

[0032] The preparation steps of diphenyldichlorosilane are as follows: In a three-necked flask, 24 parts of anhydrous magnesium chips were added, and 200 parts of bromobenzene were slowly added dropwise at 0-5°C under nitrogen protection. A small amount of anhydrous ether was added as a solvent during the dropwise addition process to generate a phenyl magnesium bromide reagent. After the solution was clarified, it was slowly added to a solution of 100 parts of trichlorosilane in anhydrous ether, and the temperature of the system was maintained at 10-15°C. The molar ratio was controlled to be PhMgBr:SiCl4 = 2.2:1.0. After the reaction was completed, the temperature was increased to 60°C and stirred at reflux for 4h to promote the elimination of by-products. The reaction solution was hydrolyzed, separated into layers, and the organic layer was washed with 5wt.% NaHCO3 solution and saturated sodium chloride solution in sequence to remove acidic impurities. The crude product was dried with anhydrous magnesium sulfate, and then purified by distillation under reduced pressure (boiling point 140-145°C / 0.5kPa) to obtain diphenyldichlorosilane with a purity of ≥98%. This method can effectively improve the yield of diphenyldichlorosilane to 75-80% and reduce the generation of by-products such as triphenylchlorosilane by controlling the molar ratio and low-temperature dropwise addition.

[0033] The preparation steps of methyltrichlorosilane are as follows: In a fixed bed reactor, 100 parts of metal silicon powder with an average particle size of 20-40μm were filled, and 2-3wt.% of copper powder was added as a main catalyst, and 0.5-1wt.% of zinc powder was added as a cocatalyst. The reaction temperature was controlled at 280-300°C, and the pressure was maintained at 0.25-0.35MPa. The flow rate of methyl chloride gas was controlled at 0.5-1.5mol / (kg·h), and the reaction time was 8-10h. Under these conditions, methyltrichlorosilane was generated as the main product, and its yield could reach 70-80%. The crude product after reaction was collected by condensation, and then purified by fractional distillation at 65-70°C / 10kPa to obtain methyltrichlorosilane with a purity of ≥99%. By adjusting the catalyst ratio and gas flow rate, the proportion of dimethyldichlorosilane by-product can be effectively reduced, thereby improving the selectivity and purity of methyltrichlorosilane.

[0034] The preparation steps of dimethyldichlorosilane are as follows: After 100 parts of metal silicon powder and 3-5 parts of copper powder were uniformly mixed, they were loaded into a fluidized bed reactor. The reaction temperature was set to 290-310°C, and the reaction pressure was controlled at 0.3-0.5MPa. Methyl chloride gas was introduced, and the flow rate was controlled at 1.0-2.0mol / (kg·h), and the reaction was continued for 6-8h. Under these conditions, dimethyldichlorosilane was generated as the main product, and the by-products were methyltrichlorosilane and trimethylchlorosilane. After the crude product was separated, it was separated by fractional distillation at 70-75°C / 8kPa, and the fraction was collected to obtain dimethyldichlorosilane with a purity of ≥98%. This process can enhance the selectivity of dimethyldichlorosilane by moderately increasing the reaction pressure and gas flow rate, so that its yield can reach 65-75%.

[0035] The preparation steps of hexamethyldisiloxane are as follows: In a stirred tank, 200 parts of trimethylchlorosilane were added, and 100 parts of deionized water were slowly added dropwise while controlling the temperature at 0-5°C to avoid violent heat release. The molar ratio was controlled at Me3SiCl:H2O = 2.2:1.0, and nitrogen protection was maintained. Trimethylsilanol and hydrogen chloride were generated during the hydrolysis process, and after the reaction was completed, 10wt.% NaOH solution was used for washing to remove residual HCl. The obtained trimethylsilanol was subjected to condensation reaction to generate hexamethyldisiloxane at 60-70°C under reflux for 3-4h in the presence of an acidic catalyst (p-toluenesulfonic acid, 0.1wt.%). The crude product was subjected to reduced pressure distillation (boiling point 100-105°C / 5kPa) to obtain hexamethyldisiloxane with purity ≥99%. By strictly controlling the hydrolysis temperature and condensation time, the generation of by-products such as trimethylsilicether can be effectively avoided, and the yield of the target product can be improved.

[0036] Reference Figure 1 A preparation method of high-refractive phenyl silicone oil, based on the high-refractive phenyl silicone oil raw material described above, includes the following specific steps: S1, formula weighing and solvent preloading: In a reaction kettle with stirring, condensation, tail gas absorption and nitrogen sealing, according to the target refractive index and viscosity, 30-60 parts of phenyltrichlorosilane, 10-30 parts of diphenyldichlorosilane, 5-15 parts of methyltrichlorosilane, and 15-35 parts of dimethyldichlorosilane were sequentially added; 10-50 parts of solvent (toluene or dichloroethane, used in the reaction) were added to facilitate heat transfer and flowability control. Replace with nitrogen, and control the oxygen content to be <0.5vol.%; Pre-cool the kettle temperature to 0-5°C for standby. Through the interval combination of the four types of chlorosilanes, the phenyl / methyl ratio basis that can realize n_D(25°C)≈1.50-1.58 after subsequent polycondensation is formed.

[0037] S2, segmented co-hydrolysis and heat release control: Keep at 0-10°C, and add deionized water (ice-salt water cooling) in segments by metering pump, and when the equivalent ratio H2O:Cl is 1.05-1.20 based on the theoretical chlorine amount of the system, the first drop of water accounts for 60-70% of the total water, the kettle pressure is controlled at 0.05-0.15MPa, and the drop time is controlled at 1.0-2.0h; The second time makes up the balance, and the temperature is raised to 20-30°C for 1.0-2.0h to complete the hydrolysis. The tail gas HCl enters the alkali washing tower for absorption. Track the acid value online, and the target is ≤5mgKOH / g. By low-temperature segmented water supply, the early gelation of high-phenyl system is inhibited, and the subsequent condensation molecular weight is controllable.

[0038] S3, catalytic condensation and synchronous end-capping of hexamethyldisiloxane: Switch to condensation phase, temperature up to 90-120°C, add catalyst (ferric chloride / tetrabutylammonium chloride / potassium aluminum sulfate) 0.05-0.5 parts, maintain stirring; continue to rise to 110-130°C for 2-6h of silanol condensation. According to the target number average degree of polymerization, add 1-5 parts of hexamethyldisiloxane twice (about 30% at the beginning, about 70% at the end) to realize synchronous end sealing, and monitor the kinematic viscosity v(25°C) in real time whether it enters the design window (such as 100-10000mm² / s). During the condensation process, end sealing can converge the molecular weight distribution, improve the transparency, and reduce the burden of rebalancing in the later stage.

[0039] S4, deacidification and dehydration, and low boiling point substance removal: After condensation, bubble with nitrogen to sweep acid for 0.5-1.0h, then reduce the pressure to 2-8kPa, and the temperature to 120-150°C to implement vacuum evaporation / thin film evaporation to remove low boiling point substances and solvents to ≤500ppm. If necessary, add an appropriate amount of adsorption purifying agent and stir at 80-100°C for 0.5-1.0h, then hot filter (1.0μm). Control indicators: acid value ≤0.2mgKOH / g, moisture (Karl Fischer) ≤100ppm. Through strict deacidification and dehydration, the long-term consistency of refractive index and thermal stability is ensured.

[0040] S5, combined fine adjustment of refractive index-molecular weight: Maintain the system at 120-130°C for short-range rebalancing for 0.5-2h until n_D(25°C) reaches the set value (such as 1.52 / 1.55 / 1.57±0.002) and the viscosity is in the target window; if necessary, add a small amount of hexamethyldisiloxane (for example 0.1-0.5 parts) as a tail end sealing plug, then stop the catalyst and fine filter (0.45μm). The "rebalancing + tail end sealing" closed loop corrects the segment distribution, achieving accurate landing of both refractive index and viscosity.

[0041] S6, polishing filtration, degassing, and inspection and filling: Polish filtration (0.20μm) at 60-80°C, vacuum degassing to ≤0.1vol.% of dissolved gas. Item by item detection: refractive index n_D(25°C) (target 1.50-1.58, tolerance ±0.002), viscosity (25°C), acid value (≤0.10mgKOH / g), moisture (≤50ppm), color (APHA ≤50), 150°C / 1h volatile matter (≤0.5wt.%), dielectric parameters (1kHz), and TGA 5% weight loss temperature ≥350°C, etc. After passing, fill, seal, and code traceability under nitrogen seal. Thus, a finished high-refractive phenyl silicone oil is obtained.

[0042] Example 1: A high-refractive phenyl silicone oil, comprising the following raw materials by weight: Phenyltrichlorosilane 30 parts; diphenyldichlorosilane 10 parts; methyltrichlorosilane 15 parts; dimethyldichlorosilane 35 parts; hexamethyldisiloxane 1 part; catalyst (optionally iron trichloride, same below) 0.05 parts; solvent (optionally toluene, same below) 10 parts.

[0043] The preparation steps of phenyltrichlorosilane are as follows: In a corrosion-resistant reaction kettle, 100 parts of industrial silicon powder with an average particle size of 20-40 μm were added, a copper / zinc powder mixture was used as a catalyst, and the amount of catalyst was controlled at 3.0 wt.% of the mass of the industrial silicon powder. The system was passed with dry hydrogen chloride gas at 300°C, and benzene was continuously added dropwise, with a molar ratio of benzene:industrial silicon powder:hydrogen chloride = 1.0:1.2:3.0. The pressure was maintained at 0.3 MPa during the reaction, and the reaction time was about 7 h. The dropwise rate of benzene was strictly controlled (1.0 mL / min). After the reaction was completed, the crude product was subjected to reduced-pressure distillation (100°C, 0.08 MPa) to remove low-boiling substances, and then separated by a fractional distillation column at 155°C / 1.0 kPa to obtain phenyltrichlorosilane with a purity of ≥99%.

[0044] The preparation steps of diphenyldichlorosilane are as follows: In a three-necked flask, 24 parts of anhydrous magnesium turnings were added, and 200 parts of bromobenzene were slowly added dropwise at 3°C under nitrogen protection, with a small amount of anhydrous ether added as a solvent during the dropwise addition to form a phenylmagnesium bromide reagent. After the solution was clarified, it was slowly added to a solution of 100 parts of trichlorosilane in anhydrous ether, and the temperature of the system was maintained at 15°C, with a molar ratio of PhMgBr:SiCl4 controlled at 2.2:1.0. After the reaction was completed, the temperature was raised to 60°C and stirred at reflux for 4 h. The reaction liquid was hydrolyzed and separated into layers, and the organic layer was washed with 5 wt.% NaHCO3 solution and saturated sodium chloride solution in sequence to remove acidic impurities. The crude product was dried with anhydrous magnesium sulfate, and then purified by reduced-pressure distillation (boiling point 140°C / 0.5 kPa) to obtain diphenyldichlorosilane with a purity of ≥98%.

[0045] The preparation steps of methyltrichlorosilane are as follows: In a fixed-bed reactor, 100 parts of metal silicon powder with an average particle size of 20-40 μm were filled, and 2 wt.% of copper powder was added as a main catalyst, and 0.5 wt.% of zinc powder was added as a cocatalyst. The reaction temperature was controlled at 290°C, and the pressure was maintained at 0.3 MPa. The flow rate of methyl chloride gas was controlled at 1.0 mol / (kg·h), and the reaction time was 9 h. The crude product after the reaction was collected by condensation, and then refined by a fractional distillation column at 65°C / 10 kPa to obtain methyltrichlorosilane with a purity of ≥99%.

[0046] The preparation steps of dimethyldichlorosilane are as follows: The metal silicon powder 100 parts and copper powder 4 parts are uniformly mixed and then loaded into a fluidized bed reactor. The reaction temperature is set to 300℃, and the reaction pressure is controlled at 0.4MPa. Methyl chloride gas is introduced, and the flow rate is controlled at 1.5mol / (kg·h), and the reaction is continued for 7h. After the crude product is separated, it is separated by rectification at 70℃ / 8kPa, and the fraction is collected to obtain dimethyldichlorosilane with a purity of ≥98%.

[0047] The preparation steps of hexamethyldisiloxane are as follows: In a stirred tank, 200 parts of trimethylchlorosilane are added, and 100 parts of deionized water are slowly added dropwise while controlling the temperature at 5℃ to avoid violent heat release. The molar ratio is controlled at Me3SiCl:H2O=2.2:1.0, and nitrogen protection is maintained. Trimethylsilanol and hydrogen chloride are generated during the hydrolysis process, and after the reaction is completed, 10wt.% NaOH solution is used for washing to remove residual HCl. The obtained trimethylsilanol is subjected to condensation reaction to generate hexamethyldisiloxane in the presence of an acidic catalyst (p-toluenesulfonic acid, 0.1wt.%) at 65℃ for 4h. The crude product is subjected to vacuum distillation (boiling point 100℃ / 5kPa) to obtain hexamethyldisiloxane with a purity of ≥99%.

[0048] A preparation method of a high-refractive phenyl silicone oil, comprising the following specific steps: S1, formula weighing and solvent preloading: proportionally adding phenyltrichlorosilane, diphenyldichlorosilane, methyltrichlorosilane, dimethyldichlorosilane and solvent into a reaction kettle under nitrogen protection and low temperature preparation; S2, stepwise co-hydrolysis and heat release control: stepwise adding water for co-hydrolysis at 5℃, controlling the H2O to chlorine equivalent ratio, completing in two stages, and absorbing tail gas HCl with lye; S3, catalytic condensation and synchronous end-capping of hexamethyldisiloxane: adding catalyst at 105℃ to perform condensation reaction, while adding hexamethyldisiloxane in batches for end-capping, controlling molecular weight and viscosity; S4, deacidification and dehydration and removal of low-boiling substances: after reaction, heating under reduced pressure to remove solvent and low-boiling substances, scanning acid with nitrogen, adding adsorbent for purification, and controlling acid value and moisture content within a specified range; S5, refractive index-molecular weight combined fine adjustment: maintaining 125℃ for short-range rebalancing to regulate refractive index and viscosity, supplementing hexamethyldisiloxane end-capping to ensure accurate performance; S6, polishing filtration, degassing and inspection and filling: the material is polished, filtered and vacuum degassed, and after the refractive index, viscosity and acid value indicators are qualified, filling and packaging are completed under nitrogen protection.

[0049] Example 2: A high-refractive phenyl silicone oil, comprising the following raw materials by weight: Phenyltrichlorosilane 50 parts; diphenyldichlorosilane 20 parts; methyltrichlorosilane 10 parts; dimethyldichlorosilane 25 parts; hexamethyldisiloxane 3 parts; catalyst 0.20 parts; solvent 30 parts.

[0050] The preparation steps of the phenyltrichlorosilane are as follows: In a corrosion-resistant reaction kettle, 100 parts of industrial silicon powder with an average particle size of 20-40 μm were added, a copper / zinc powder mixture was used as the catalyst, and the amount of catalyst was controlled at 3.0 wt.% of the mass of the industrial silicon powder. The system was passed with dry hydrogen chloride gas at 300°C, and benzene was continuously added dropwise, with a molar ratio of benzene:industrial silicon powder:hydrogen chloride = 1.0:1.2:3.0. The pressure was maintained at 0.3 MPa during the reaction, and the reaction time was about 7 h. The dropwise rate of benzene was strictly controlled (1.0 mL / min). After the reaction was completed, the crude product was subjected to reduced-pressure distillation (100°C, 0.08 MPa) to remove low-boiling substances, and then was separated by a fractional distillation column at 155°C / 1.0 kPa to obtain phenyltrichlorosilane with a purity of ≥99%.

[0051] The preparation steps of the diphenyldichlorosilane are as follows: In a three-necked flask, 24 parts of anhydrous magnesium turnings were added, and 200 parts of bromobenzene were slowly added dropwise at 3°C under nitrogen protection, with a small amount of anhydrous ether being added as a solvent during the dropwise addition to generate a phenylmagnesium bromide reagent. After the solution was clarified, it was slowly added to a solution of 100 parts of trichlorosilane in anhydrous ether, the temperature of the system was maintained at 15°C, and the molar ratio was controlled at PhMgBr:SiCl4 = 2.2:1.0. After the reaction was completed, the temperature was increased to 60°C and the reaction was stirred at reflux for 4 h. The reaction liquid was hydrolyzed and separated into layers, the organic layer was washed with 5 wt.% NaHCO3 solution and saturated sodium chloride solution in sequence to remove acidic impurities. The crude product was dried over anhydrous magnesium sulfate, and then was purified by reduced-pressure distillation (boiling point 140°C / 0.5 kPa) to obtain diphenyldichlorosilane with a purity of ≥98%.

[0052] The preparation steps of the methyltrichlorosilane are as follows: In a fixed-bed reactor, 100 parts of metal silicon powder with an average particle size of 20-40 μm were filled, and 2 wt.% of copper powder was added as the main catalyst, and 0.5 wt.% of zinc powder was added as the auxiliary catalyst. The reaction temperature was controlled at 290°C, and the pressure was maintained at 0.3 MPa. The flow rate of methyl chloride gas was controlled at 1.0 mol / (kg·h), and the reaction time was 9 h. The crude product after the reaction was collected by condensation, and was subjected to rectification in a fractional distillation column at 65°C / 10 kPa to obtain methyltrichlorosilane with a purity of ≥99%.

[0053] The preparation steps of the dimethyldichlorosilane are as follows: The metal silicon powder 100 parts and copper powder 4 parts are uniformly mixed and loaded into a fluidized bed reactor, the reaction temperature is set to 300℃, and the reaction pressure is controlled at 0.4MPa. Methyl chloride gas is introduced, the flow rate is controlled at 1.5mol / (kg·h), and the reaction is continued for 7h. After the crude product is separated, it is separated by rectification at 70℃ / 8kPa, the fraction is collected, and dimethyldichlorosilane with a purity of ≥98% is obtained.

[0054] The preparation steps of hexamethyldisiloxane are as follows: In a stirred tank, 200 parts of trimethylchlorosilane are added, 100 parts of deionized water are slowly added dropwise, and the temperature is controlled at 5℃ to avoid violent heat release. The molar ratio is controlled at Me3SiCl:H2O=2.2:1.0, and nitrogen protection is maintained. Trimethylsilanol and hydrogen chloride are generated during hydrolysis, and after the reaction is completed, 10wt.% NaOH solution is used for washing to remove residual HCl. The obtained trimethylsilanol is subjected to condensation reaction to generate hexamethyldisiloxane in the presence of an acidic catalyst (p-toluenesulfonic acid, 0.1wt.%) at 65℃ for 4h. The crude product is subjected to vacuum distillation (boiling point 100℃ / 5kPa) to obtain hexamethyldisiloxane with a purity of ≥99%.

[0055] A preparation method of a high-refractive phenyl silicone oil, comprising the following specific steps: S1, formula weighing and solvent preloading: proportionally adding phenyltrichlorosilane, diphenyldichlorosilane, methyltrichlorosilane, dimethyldichlorosilane and solvent into a reaction kettle, nitrogen protection, low temperature preparation; S2, staged co-hydrolysis and heat release control: staged dropwise addition of water at 3℃ for co-hydrolysis, control of H2O and chlorine equivalent ratio, completion in two stages, tail gas HCl is absorbed by lye; S3, catalytic condensation and synchronous end-capping of hexamethyldisiloxane: adding catalyst at 95℃ for condensation reaction, while adding hexamethyldisiloxane end-capping in batches, control of molecular weight and viscosity; S4, deacidification and dehydration, and removal of low-boiling substances: after reaction, heating under reduced pressure to remove solvent and low-boiling substances, nitrogen acid scanning, addition of adsorbent for purification, control of acid value and moisture in the specified range; S5, refractive index-molecular weight combined fine adjustment: maintaining 120℃ for short-range rebalancing, regulating refractive index and viscosity, supplementing hexamethyldisiloxane end-capping to ensure accurate performance; S6, polishing filtration, degassing and inspection and filling: the material is polished, filtered and vacuum degassed, and after the refractive index, viscosity and acid value indicators are qualified, nitrogen protection is completed for filling and packaging.

[0056] Example 3: A high-refractive phenyl silicone oil, comprising the following raw materials by weight: Phenyltrichlorosilane 60 parts; diphenyldichlorosilane 30 parts; methyltrichlorosilane 5 parts; dimethyldichlorosilane 15 parts; hexamethyldisiloxane 5 parts; catalyst 0.50 parts; solvent 50 parts.

[0057] The preparation steps of the phenyltrichlorosilane are as follows: In a corrosion-resistant reaction kettle, 100 parts of industrial silicon powder with an average particle size of 20-40 μm were added, a copper / zinc powder mixture was used as the catalyst, and the amount of catalyst was controlled at 3.0 wt.% of the mass of the industrial silicon powder. The system was passed with dry hydrogen chloride gas at 300°C, and benzene was continuously added dropwise, with a molar ratio of benzene:industrial silicon powder:hydrogen chloride = 1.0:1.2:3.0. The pressure was maintained at 0.3 MPa during the reaction, and the reaction time was about 7 h. The dropwise rate of benzene was strictly controlled (1.0 mL / min). After the reaction was completed, the crude product was subjected to reduced-pressure distillation (100°C, 0.08 MPa) to remove low-boiling substances, and then was separated by a fractional distillation column at 155°C / 1.0 kPa to obtain phenyltrichlorosilane with a purity of ≥99%.

[0058] The preparation steps of the diphenyldichlorosilane are as follows: In a three-necked flask, 24 parts of anhydrous magnesium turnings were added, and 200 parts of bromobenzene were slowly added dropwise at 3°C under nitrogen protection, with a small amount of anhydrous ether being added as a solvent during the dropwise addition to generate a phenylmagnesium bromide reagent. After the solution was clarified, it was slowly added to a solution of 100 parts of trichlorosilane in anhydrous ether, the temperature of the system was maintained at 15°C, and the molar ratio was controlled at PhMgBr:SiCl4 = 2.2:1.0. After the reaction was completed, the temperature was increased to 60°C and the reaction was stirred at reflux for 4 h. The reaction liquid was hydrolyzed and separated into layers, the organic layer was washed with 5 wt.% NaHCO3 solution and saturated sodium chloride solution in sequence to remove acidic impurities. The crude product was dried over anhydrous magnesium sulfate, and then was purified by reduced-pressure distillation (boiling point 140°C / 0.5 kPa) to obtain diphenyldichlorosilane with a purity of ≥98%.

[0059] The preparation steps of the methyltrichlorosilane are as follows: In a fixed-bed reactor, 100 parts of metal silicon powder with an average particle size of 20-40 μm were filled, and 2 wt.% of copper powder was added as the main catalyst, and 0.5 wt.% of zinc powder was added as the auxiliary catalyst. The reaction temperature was controlled at 290°C, and the pressure was maintained at 0.3 MPa. The flow rate of methyl chloride gas was controlled at 1.0 mol / (kg·h), and the reaction time was 9 h. The crude product after the reaction was collected by condensation, and was subjected to rectification in a fractional distillation column at 65°C / 10 kPa to obtain methyltrichlorosilane with a purity of ≥99%.

[0060] The preparation steps of the dimethyldichlorosilane are as follows: The metal silicon powder 100 parts and copper powder 4 parts are uniformly mixed and loaded into a fluidized bed reactor, the reaction temperature is set to 300℃, and the reaction pressure is controlled at 0.4MPa. Methyl chloride gas is introduced, the flow rate is controlled at 1.5mol / (kg·h), and the reaction is continued for 7h. After the crude product is separated, it is separated by rectification at 70℃ / 8kPa, the fraction is collected, and dimethyldichlorosilane with a purity of ≥98% is obtained.

[0061] The preparation steps of hexamethyldisiloxane are as follows: In a stirred tank, 200 parts of trimethylchlorosilane are added, 100 parts of deionized water are slowly added dropwise, and the temperature is controlled at 5℃ to avoid violent heat release. The molar ratio is controlled at Me3SiCl:H2O=2.2:1.0, and nitrogen protection is maintained. Trimethylsilanol and hydrogen chloride are generated during hydrolysis, and after the reaction is completed, 10wt.% NaOH solution is used for washing to remove residual HCl. The obtained trimethylsilanol is subjected to condensation reaction to generate hexamethyldisiloxane in the presence of an acidic catalyst (p-toluenesulfonic acid, 0.1wt.%) at 65℃ under reflux for 4h. The crude product is subjected to vacuum distillation (boiling point 100℃ / 5kPa) to obtain hexamethyldisiloxane with a purity of ≥99%.

[0062] A preparation method of a high-refractive phenyl silicone oil, comprising the following specific steps: S1, formula weighing and solvent preloading: phenyltrichlorosilane, diphenyldichlorosilane, methyltrichlorosilane, dimethyldichlorosilane and solvent are added to the reaction kettle according to the proportion, nitrogen protection, low temperature preparation; S2, stepwise co-hydrolysis and heat release control: co-hydrolysis is carried out by adding water dropwise at 10℃, the H2O / chlorine equivalent ratio is controlled, and the process is completed in two stages, and the tail gas HCl is absorbed by lye; S3, catalytic condensation and synchronous end-capping of hexamethyldisiloxane: the temperature is raised to 120℃ to add catalyst, condensation reaction is carried out, and hexamethyldisiloxane is added in batches for end-capping, the molecular weight and viscosity are controlled; S4, deacidification and dehydration and removal of low-boiling substances: after the reaction, the pressure is reduced and heated to remove solvent and low-boiling substances, nitrogen is scanned for acid, adsorbent is added for purification, and the acid value and moisture content are controlled within the specified range; S5, refractive index-molecular weight combined fine adjustment: short-range rebalancing is maintained at 130℃ to adjust the refractive index and viscosity, hexamethyldisiloxane is added for tail end-capping to ensure accurate performance; S6, polishing filtration, degassing and inspection and filling: the material is polished, filtered and vacuum degassed, and after the refractive index, viscosity and acid value indicators are qualified, filling and packaging are completed under nitrogen protection.

[0063] Comparative Example 1 (low phenyl content): A phenyl silicone oil, comprising the following raw materials by weight: Phenyltrichlorosilane 25 parts; diphenyldichlorosilane 8 parts; methyltrichlorosilane 18 parts; dimethyldichlorosilane 38 parts; hexamethyldisiloxane 1 part; catalyst 0.05 parts; solvent 10 parts.

[0064] The preparation steps of the phenyltrichlorosilane are as follows: In a corrosion-resistant reaction kettle, 100 parts of industrial silicon powder with an average particle size of 20-40 μm were added, a copper / zinc powder mixture was used as the catalyst, and the amount of catalyst was controlled at 3.0 wt.% of the mass of the industrial silicon powder. The system was passed with dry hydrogen chloride gas at 300°C, and benzene was continuously added dropwise, with a molar ratio of benzene:industrial silicon powder:hydrogen chloride = 1.0:1.2:3.0. The pressure was maintained at 0.3 MPa during the reaction, and the reaction time was about 7 h. The dropwise rate of benzene was strictly controlled (1.0 mL / min). After the reaction was completed, the crude product was subjected to reduced-pressure distillation (100°C, 0.08 MPa) to remove low-boiling substances, and then was separated by a fractional distillation column at 155°C / 1.0 kPa to obtain phenyltrichlorosilane with a purity of ≥99%.

[0065] The preparation steps of the diphenyldichlorosilane are as follows: In a three-necked flask, 24 parts of anhydrous magnesium turnings were added, and 200 parts of bromobenzene were slowly added dropwise at 3°C under nitrogen protection, with a small amount of anhydrous ether being added as a solvent during the dropwise addition to generate a phenylmagnesium bromide reagent. After the solution was clarified, it was slowly added to a solution of 100 parts of trichlorosilane in anhydrous ether, the temperature of the system was maintained at 15°C, and the molar ratio was controlled at PhMgBr:SiCl4 = 2.2:1.0. After the reaction was completed, the temperature was raised to 60°C and stirring was performed under reflux for 4 h. The reaction liquid was hydrolyzed and separated into layers, the organic layer was washed with 5 wt.% NaHCO3 solution and saturated sodium chloride solution in sequence to remove acidic impurities. The crude product was dried over anhydrous magnesium sulfate, and then was purified by reduced-pressure distillation (boiling point 140°C / 0.5 kPa) to obtain diphenyldichlorosilane with a purity of ≥98%.

[0066] The preparation steps of the methyltrichlorosilane are as follows: In a fixed-bed reactor, 100 parts of metal silicon powder with an average particle size of 20-40 μm were filled, and 2 wt.% of copper powder was added as a main catalyst, and 0.5 wt.% of zinc powder was added as a cocatalyst. The reaction temperature was controlled at 290°C, and the pressure was maintained at 0.3 MPa. The flow rate of methyl chloride gas was controlled at 1.0 mol / (kg·h), and the reaction time was 9 h. The crude product after the reaction was collected by condensation, and was subjected to rectification in a fractional distillation column at 65°C / 10 kPa to obtain methyltrichlorosilane with a purity of ≥99%.

[0067] The preparation steps of the dimethyldichlorosilane are as follows: The metal silicon powder 100 parts and copper powder 4 parts are uniformly mixed and loaded into a fluidized bed reactor, the reaction temperature is set to 300℃, and the reaction pressure is controlled at 0.4MPa. Methyl chloride gas is introduced, the flow rate is controlled at 1.5mol / (kg·h), and the reaction is continued for 7h. After the crude product is separated, it is separated by rectification at 70℃ / 8kPa, the fraction is collected, and dimethyldichlorosilane with a purity of ≥98% is obtained.

[0068] The preparation steps of hexamethyldisiloxane are as follows: In a stirred tank, 200 parts of trimethylchlorosilane are added, 100 parts of deionized water are slowly added dropwise, and the temperature is controlled at 5℃ to avoid violent heat release. The molar ratio is controlled at Me3SiCl:H2O=2.2:1.0, and nitrogen protection is maintained. Trimethylsilanol and hydrogen chloride are generated during hydrolysis, and after the reaction is completed, 10wt.% NaOH solution is used for washing to remove residual HCl. The obtained trimethylsilanol is subjected to condensation reaction to generate hexamethyldisiloxane in the presence of an acidic catalyst (p-toluenesulfonic acid, 0.1wt.%) at 65℃ under reflux for 4h. The crude product is subjected to vacuum distillation (boiling point 100℃ / 5kPa) to obtain hexamethyldisiloxane with a purity of ≥99%.

[0069] A preparation method of a high-refractive phenyl silicone oil, comprising the following specific steps: S1, formula weighing and solvent preloading: phenyltrichlorosilane, diphenyldichlorosilane, methyltrichlorosilane, dimethyldichlorosilane and solvent are added to the reaction kettle in proportion, nitrogen protection, low temperature preparation; S2, stepwise co-hydrolysis and heat release control: stepwise co-hydrolysis is carried out at 5℃, the H2O / chlorine equivalent ratio is controlled, and the process is completed in two stages, and the tail gas HCl is absorbed by lye; S3, catalytic condensation and synchronous end-capping of hexamethyldisiloxane: the temperature is raised to 105℃ to add catalyst, condensation reaction is carried out, and hexamethyldisiloxane is added in batches for end-capping, the molecular weight and viscosity are controlled; S4, deacidification and dehydration, and removal of low-boiling substances: after the reaction, the pressure is reduced and heated to remove solvent and low-boiling substances, nitrogen is scanned for acid, adsorbent is added for purification, and the acid value and moisture content are controlled within the specified range; S5, refractive index-molecular weight combined fine adjustment: short-range rebalancing is maintained at 125℃ to adjust the refractive index and viscosity, and hexamethyldisiloxane is added for tail end-capping to ensure accurate performance; S6, polishing filtration, degassing and inspection and filling: the material is polished, filtered and vacuum degassed, and after the refractive index, viscosity and acid value indicators are qualified, nitrogen protection is completed for filling and packaging.

[0070] Comparative Example 2 (insufficient end-capping, viscosity and stability out of control): A high-refractive phenyl silicone oil, comprising the following raw materials by weight: Phenyltrichlorosilane 60 parts; diphenyldichlorosilane 30 parts; methyltrichlorosilane 5 parts; dimethyldichlorosilane 15 parts; catalyst 0.20 parts; solvent 40 parts.

[0071] The preparation steps of phenyltrichlorosilane are as follows: In a corrosion-resistant reaction kettle, 100 parts of industrial silicon powder with an average particle size of 20-40 μm were added, a copper / zinc powder mixture was used as the catalyst, and the amount of catalyst was controlled at 3.0 wt.% of the mass of the industrial silicon powder. The system was passed with dry hydrogen chloride gas at 300°C, and benzene was continuously added dropwise, with a molar ratio of benzene:industrial silicon powder:hydrogen chloride = 1.0:1.2:3.0. The pressure was maintained at 0.3 MPa during the reaction, and the reaction time was about 7 h. The dropwise rate of benzene was strictly controlled (1.0 mL / min). After the reaction was completed, the crude product was subjected to reduced-pressure distillation (100°C, 0.08 MPa) to remove low-boiling substances, and then was separated by a fractional distillation column at 155°C / 1.0 kPa to obtain phenyltrichlorosilane with a purity of ≥99%.

[0072] The preparation steps of diphenyldichlorosilane are as follows: In a three-necked flask, 24 parts of anhydrous magnesium turnings were added, and 200 parts of bromobenzene were slowly added dropwise at 3°C under nitrogen protection, with a small amount of anhydrous ether being added as a solvent during the dropwise addition to generate a phenylmagnesium bromide reagent. After the solution was clarified, it was slowly added to a solution of 100 parts of trichlorosilane in anhydrous ether, and the temperature of the system was maintained at 15°C, with a molar ratio of PhMgBr:SiCl4 being controlled at 2.2:1.0. After the reaction was completed, the temperature was increased to 60°C and the system was stirred at reflux for 4 h. The reaction liquid was hydrolyzed and separated into layers, and the organic layer was washed with 5 wt.% NaHCO3 solution and saturated sodium chloride solution in sequence to remove acidic impurities. The crude product was dried over anhydrous magnesium sulfate, and then was purified by reduced-pressure distillation (boiling point 140°C / 0.5 kPa) to obtain diphenyldichlorosilane with a purity of ≥98%.

[0073] The preparation steps of methyltrichlorosilane are as follows: In a fixed-bed reactor, 100 parts of metal silicon powder with an average particle size of 20-40 μm were filled, and 2 wt.% of copper powder was added as a main catalyst, and 0.5 wt.% of zinc powder was added as a cocatalyst. The reaction temperature was controlled at 290°C, and the pressure was maintained at 0.3 MPa. The flow rate of methyl chloride gas was controlled at 1.0 mol / (kg·h), and the reaction time was 9 h. The crude product after the reaction was collected by condensation, and was subjected to rectification in a fractional distillation column at 65°C / 10 kPa to obtain methyltrichlorosilane with a purity of ≥99%.

[0074] The preparation steps of dimethyldichlorosilane are as follows: The metal silicon powder 100 parts and copper powder 4 parts are uniformly mixed and then loaded into a fluidized bed reactor, the reaction temperature is set to 300℃, and the reaction pressure is controlled at 0.4 MPa. Methyl chloride gas is introduced, the flow rate is controlled at 1.5 mol / (kg·h), and the reaction is continued for 7 h. After the crude product is separated, it is separated by rectification at 70℃ / 8kPa, and the fraction is collected to obtain dimethyldichlorosilane with a purity of ≥98%.

[0075] A preparation method of high-refractive phenyl silicone oil, comprising the following specific steps: S1, formula weighing and solvent preloading: phenyltrichlorosilane, diphenyldichlorosilane, methyltrichlorosilane, dimethyldichlorosilane and solvent are added to the reaction kettle according to the proportion, nitrogen protection, low temperature preparation; S2, staged co-hydrolysis and heat release control: co-hydrolysis is carried out by adding water at 5℃ in stages, the H2O / chlorine equivalent ratio is controlled, and the reaction is completed in two stages, and the tail gas HCl is absorbed by lye; S3, catalytic condensation: the temperature is raised to 105℃ to add catalyst for condensation reaction; S4, deacidification and dehydration and removal of low-boiling substances: after the reaction, the pressure is reduced and heated to remove the solvent and low-boiling substances, nitrogen is scanned for acid, adsorbent is added for purification, and the acid value and moisture content are controlled within the specified range; S5, polishing filtration, degassing and testing and filling: the material is polished, filtered and vacuum degassed, and after the refractive index, viscosity and acid value indicators meet the requirements, filling and packaging are completed under nitrogen protection.

[0076] The products of the above examples and comparative examples are tested for appearance and physicochemical properties, and optical and thermal / electrical properties, and the results are shown in Tables 1 and 2, respectively.

[0077] The test methods are as follows: The refractive index is measured by Abbe refractometer according to GB / T 6488-2008 Determination of refractive index of optical glass, and the test temperature is controlled at 25±0.1℃.

[0078] The kinematic viscosity is measured according to GB / T 265-1988 Determination of kinematic viscosity of petroleum products (Ubbelohde viscometer method), and the average value is taken as the result.

[0079] The acid value is determined according to GB / T 4945-2002 Determination of acid value of silicon oil with potassium hydroxide standard solution titration, and converted to acid value.

[0080] The moisture content is determined by GB / T 6283-2008 Determination of moisture content of chemical products by Karl Fischer method, and the moisture content is directly read out.

[0081] The color is determined according to GB / T 3143-1982 Determination of color of liquid chemical products by platinum-cobalt color number method, and the average reading is taken.

[0082] Volatile matter was determined by ASTM D972-21 method for volatile matter in silicone fluids, at 150°C for 1 hour, and the mass loss percentage was determined.

[0083] Transmittance was determined by GB / T 2410-2008 method for determination of luminous transmittance and haze of transparent plastics, on a spectrophotometer, and the luminous transmittance was measured at 450 nm wavelength.

[0084] Haze was also determined by GB / T 2410-2008 method, using the integrating sphere method.

[0085] TGA 5% weight loss temperature was determined by GB / T 19466.6-2009 method for plastics - differential scanning calorimetry and thermogravimetry - part 6: thermogravimetric analysis, at a heating rate of 10°C / min, and the 5% weight loss temperature was recorded.

[0086] Dielectric constant and dissipation factor were determined by GB / T 1409-2006 method for power frequency electrical strength test of solid insulating materials, at 1 kHz, using a bridge, and the dielectric constant and dissipation factor were measured.

[0087] Table 1: Appearance and physico-chemical properties

[0088] Table 2: Optical and thermal / electrical properties

[0089] From the results in Table 1 and Table 2, it can be concluded that: (1) Refractive index and optical uniformity: as the ratio of phenyltrichlorosilane to diphenyldichlorosilane increased in Examples 1 / 2 / 3, the refractive index increased from 1.515 to 1.576, while maintaining a transmittance ≥ 95% and a haze ≤ 0.8%, indicating a positive effect of phenyl content on high refractive index and low scattering. In Comparative Example 1, the refractive index decreased to 1.495 and the haze increased to 2.5% due to the low phenyl content, making it difficult to meet the requirements of high optical matching scenarios.

[0090] (2) Viscosity and end-capping control: after batch end-capping and rebalancing with hexamethyldisiloxane, the viscosity of Example 2 was controlled within the processable range of 1100 mm² / s; although Example 3 had a high refractive index, the viscosity was still maintained below 3200 mm² / s. In Comparative Example 2, without the addition of hexamethyldisiloxane, the average chain length was out of control, resulting in a viscosity soaring to 9800 mm² / s, and the processability and transparency were significantly deteriorated.

[0091] (3) Stability and residue control: all three groups of examples achieved acid value ≤0.06 mgKOH / g, moisture ≤50 ppm, volatile ≤0.20 wt%, TGA 5% weight loss temperature ≥360℃, showing good thermal stability and low residue; when the comparative sample was insufficiently deacidified and dehydrated or lacked end-capping, the acid value, moisture and volatile significantly increased, the TGA temperature decreased, and the long-term reliability was limited.

[0092] In summary, by constructing a high-refractive skeleton with phenyltrichlorosilane + diphenyldichlorosilane and balancing rheology with methyltrichlorosilane + dimethyldichlorosilane, and then fine-tuning by batch end-capping with hexamethyldisiloxane and rebalancing, predictable and repeatable landing point control can be achieved on the two variables of refractive index and viscosity. Compared with the comparative examples, this process has significant advantages in optical clarity, processability and thermal / electrical stability, and is suitable for use as a dilution component or refractive index adjustment component in strict scenarios such as LED encapsulation glue, optical adhesive and high-transparency coating.

[0093] It should be noted that the above examples are only used to illustrate the technical solutions of the present application and not to limit it. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced equivalently without departing from the spirit and scope of the technical solutions of the present application, and they should be covered in the scope of the claims of the present application.

Claims

1. A method for preparing a high-refractive-index phenyl silicone oil, characterized in that, The specific steps include the following: S1. Formula weighing and solvent preloading: Add phenyltrichlorosilane, diphenyldichlorosilane, methyltrichlorosilane, dimethyldichlorosilane and solvent to the reaction vessel according to the proportion, under nitrogen protection and low temperature preparation. S2. Segmented co-hydrolysis and exothermic control: Co-hydrolysis is carried out by adding water dropwise in stages at 0–10℃, controlling the H2O to chlorine equivalent ratio, and is completed in two stages. The tail gas HCl is absorbed by alkaline solution. S3. Catalytic condensation and simultaneous end-capping with hexamethyldisiloxane: Heat to 90–120℃ and add catalyst to carry out condensation reaction, while simultaneously adding hexamethyldisiloxane in batches for end-capping to control molecular weight and viscosity. S4. Deacidification, dehydration and removal of low-boiling substances: After the reaction, the pressure is reduced and the heating is carried out to remove the solvent and low-boiling substances. Nitrogen gas is used to purge the acid, and an adsorbent is added for purification. The acid value and moisture content are controlled within the specified range. S5. Refractive index-molecular weight joint fine-tuning: Maintain 120–130℃ for short-range rebalancing, adjust refractive index and viscosity, add hexamethyldisiloxane tail-end sealing to ensure precise performance; S6. Polishing, filtration, degassing and inspection filling: After the material is polished, filtered and degassed under vacuum, and the refractive index, viscosity and acid value are tested and found to be qualified, the filling and sealing are completed under nitrogen protection. Of which, by weight, phenyltrichlorosilane is 30–60 parts, diphenyldichlorosilane is 10–30 parts, methyltrichlorosilane is 5–15 parts, dimethyldichlorosilane is 15–35 parts, hexamethyldisiloxane is 1–5 parts, catalyst is 0.05–0.5 parts, and solvent is 10–50 parts.

2. The method for preparing a high-refractive-index phenyl silicone oil according to claim 1, characterized in that, The specific preparation steps for the phenyltrichlorosilane are as follows: Industrial silicon powder with an average particle size of 10–50 μm was added to a corrosion-resistant reactor, a catalyst was added, and dry hydrogen chloride gas was introduced at 280–320 °C, while benzene was continuously added dropwise. The pressure was maintained at 0.2–0.4 MPa during the reaction, and the reaction time was 6–8 h. After the reaction is complete, the crude product is subjected to vacuum distillation at 80–120℃ and 0.08MPa to remove low-boiling substances, and then separated in a fractionation column at 150–160℃ / 1.0kPa to obtain phenyltrichlorosilane with a purity ≥99%.

3. The method for preparing a high-refractive-index phenyl silicone oil according to claim 2, characterized in that, The catalyst used in the preparation of phenyltrichlorosilane is a mixture of copper powder and zinc powder, and the amount of catalyst is controlled at 2-5 wt.% of the mass of industrial silicon powder; the molar ratio of benzene, industrial silicon powder and hydrogen chloride is 1.0:1.2:3.0; the dropping rate of benzene is controlled at 0.5-1.0 mL / min to avoid excessive generation of the byproduct diphenyldichlorosilane.

4. The method for preparing a high-refractive-index phenyl silicone oil according to claim 1, characterized in that, The specific preparation steps for the diphenyldichlorosilane are as follows: Anhydrous magnesium shavings were added to a three-necked flask, and bromobenzene was slowly added dropwise at 0–5°C under nitrogen protection. Anhydrous diethyl ether was added as a solvent during the dropwise addition to generate phenyl magnesium bromide reagent. After the solution is clarified, add anhydrous diethyl ether solution of trichlorosilane, maintain the system temperature at 10–15℃, and control the molar ratio at PhMgBr:SiCl4 = 2.2:1.0; After the reaction was completed, the temperature was raised to 60℃ and stirred under reflux for 4 hours. The reaction solution was hydrolyzed and separated into layers. The organic layer was washed successively with 5wt.% NaHCO3 solution and saturated sodium chloride solution to remove acidic impurities. The crude product was dried with anhydrous magnesium sulfate and then purified by vacuum distillation at a boiling point of 140–145℃ / 0.5kPa to obtain diphenyldichlorosilane with a purity ≥98%.

5. The method for preparing a high-refractive-index phenyl silicone oil according to claim 1, characterized in that, The specific preparation steps for the methyltrichlorosilane are as follows: A fixed-bed reactor was filled with metallic silicon powder with an average particle size of 20–40 μm and a catalyst was added. The reaction temperature was controlled at 280–300 °C and the pressure was maintained at 0.25–0.35 MPa. The flow rate of methyl chloride gas was controlled at 0.5–1.5 mol / (kg·h), the reaction time was 8–10 h, the crude product after the reaction was collected by condensation and entered a fractionation tower for distillation at 65–70 °C / 10 kPa to obtain methyltrichlorosilane with a purity ≥99%.

6. The method for preparing a high-refractive-index phenyl silicone oil according to claim 5, characterized in that, The catalyst used in the preparation of methyltrichlorosilane includes a main catalyst and a co-catalyst. The main catalyst is 2–3 wt.% copper powder, and the co-catalyst is 0.5–1 wt.% zinc powder.

7. The method for preparing a high-refractive-index phenyl silicone oil according to claim 1, characterized in that, The specific preparation steps for the dimethyldichlorosilane are as follows: The silicon powder and copper powder were uniformly mixed at a weight ratio of 20:1 and then loaded into a fluidized bed reactor. The reaction temperature was set at 290–310℃ and the reaction pressure was controlled at 0.3–0.5MPa. Methyl chloride gas was introduced at a flow rate of 1.0–2.0 mol / (kg·h) and the reaction was continued for 6–8 h. After separation, the crude product was separated by distillation at 70–75 °C / 8 kPa. The fraction was collected to obtain dimethyldichlorosilane with a purity ≥98%.

8. The method for preparing a high-refractive-index phenyl silicone oil according to claim 1, characterized in that, The specific preparation steps for the hexamethyldisiloxane are as follows: Add trimethylchlorosilane to the stirred tank, add deionized water dropwise, and control the temperature at 0–5℃ while maintaining nitrogen protection. Trimethylsilanol and hydrogen chloride are generated during hydrolysis. After the reaction is completed, the product is washed with 10 wt.% NaOH solution to remove residual HCl. The obtained trimethylsilanol is refluxed at 60–70 °C for 3–4 h in the presence of an acidic catalyst to undergo a condensation reaction to generate hexamethyldisiloxane. The crude product is then distilled under reduced pressure at 100–105 °C / 5 kPa to obtain hexamethyldisiloxane with a purity ≥99%.

9. The method for preparing a high-refractive-index phenyl silicone oil according to claim 8, characterized in that, The weight ratio of trimethylchlorosilane to deionized water is 2:1, and the molar ratio is controlled at Me3SiCl:H2O of 2.2:1.

0. The acidic catalyst is 0.1 wt.% p-toluenesulfonic acid.

10. A high-refractive-index phenyl silicone oil, characterized in that, It is prepared by the method for preparing high-refractive-index phenyl silicone oil as described in any one of claims 1-9.

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