Process for the preparation of methylphenyl silicone oil in one pot

Abstract

The application provides a method for preparing methyl phenyl silicone oil by one-pot method, comprising: S100, carrying out hydrolysis reaction of phenyl dialkoxysilane selected from methyl phenyl dimethoxysilane and diphenyl dimethoxysilane and a chain extender selected from dimethyl cyclosiloxane and alpha, omega-dihydroxypolydimethylsiloxane in the presence of water and a first catalyst at a temperature of 40-90 DEG C, and carrying out first low boiling point removal treatment; S200, adding a second catalyst and reacting at 70-160 DEG C; S300, carrying out second low boiling point removal treatment to obtain methyl phenyl silicone oil; wherein the first catalyst and the second catalyst are each independently selected from tetramethyl ammonium hydroxide silanol salt and potassium hydroxide silanol salt; and the method further comprises: adding an end-capping agent before the hydrolysis reaction in step S100 or before adding the second catalyst in step S200.

Description

Technical Field

[0001] The invention belongs to the technical field of organic silicon, and particularly relates to a method for preparing methylphenyl silicone oil by a one-pot process. Background Art

[0002] Methylphenyl silicone oil can be prepared by hydrolysis route, which usually includes hydrolysis, neutralization, washing, stratification, concentration, polycondensation, neutralization, desulfurization and other processes. Among them, hydrolysis is generally carried out by placing raw materials such as methylphenyldichlorosilane (or methylphenyldimethoxysilane) and diphenyldichlorosilane (or diphenyldimethoxysilane) into a hydrolysis kettle in the presence of toluene solvent and under acidic conditions (addition of hydrochloric acid, dilute sulfuric acid, acid clay, etc.). After hydrolysis, neutralization is carried out, and then the material is transferred to a stratification tank for stratification. After standing and stratification, the upper oil layer or the lower oil layer is taken out according to the density of the hydrolyzed material, and it is transferred to a concentration kettle for further concentration. After concentration, it is transferred to a polycondensation kettle, and the polycondensation reaction is carried out under alkaline conditions (addition of KOH alkali gel or ammonia gel, etc.), and an appropriate amount of neutralizer is added for neutralization (ammonia gel is removed after the media is broken at about 150°C). Finally, the low-boiling substances are removed through the desulfurization process, and the color is removed by filtration or activated carbon adsorption.

[0003] For example, Zhou Yiwen et al. disclosed high-viscosity phenylmethyl silicone oil and its preparation method (Study on the preparation and performance control of high-viscosity phenylmethyl silicone oil [D]. Shanghai University of Technology, 2017), Gong Yugui et al. disclosed methylphenyl vinyl silicone oil and its preparation method (Preparation and performance of methylphenyl vinyl silicone oil [J]. Silicone Materials, 2017, 31(01): 6-9), Sun Dawei et al. disclosed vinyl-terminated methylphenyl silicone oil and its preparation method (Preparation and performance characterization of vinyl-terminated methylphenyl silicone oil [J]. Adhesion, 2011, 32(05): 58-60), Zhang Chao et al. disclosed methyldiphenyl-terminated phenylmethyl silicone oil and its preparation method (Study on the synthesis of methyldiphenyl-terminated phenylmethyl silicone oil [J]. Journal of Hangzhou Normal University (Natural Science Edition), 2017, 16(01): 39-45).

[0004] Therefore, the existing hydrolysis route for preparing methylphenyl silicone oil has a complicated process (including hydrolysis, neutralization, stratification separation, concentration, polycondensation, etc.), and involves a reaction device including at least four main devices (hydrolysis kettle, static stratification device, concentration kettle, polycondensation kettle, etc.), and the investment cost is relatively high. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to address the deficiencies of the prior art and provide a method for preparing methylphenyl silicone oil by a one-pot process. The method of the present invention reduces the steps of methylphenyl silicone oil to two steps, hydrolysis and polycondensation, thereby achieving the effect of preparing methylphenyl silicone oil by a "one-pot process" and having the advantages of low investment cost for production equipment.

[0006] The object of the present application is achieved by the following technical solutions.

[0007] The present application provides a method for preparing methyl phenyl silicone oil by one-pot method, wherein the method comprises the following steps:

[0008] S100, a hydrolysis reaction of a phenyldialkoxysilane selected from methyl phenyl dimethoxysilane and diphenyl dimethoxysilane and a chain extender selected from dimethylcyclosiloxane and α, ω-dihydroxypolydimethylsiloxane is carried out at a temperature of 40-90℃ and in the presence of water and a first catalyst to obtain a hydrolysis reaction mixture, the hydrolysis reaction mixture is subjected to a first low-molecular-weight-removing treatment to obtain a hydrolysate;

[0009] S200, a second catalyst is added to the hydrolysate, and a reaction is carried out at 70-160℃, and a polycondensate is obtained after the reaction is terminated;

[0010] S300, the polycondensate is subjected to a second low-molecular-weight-removing treatment to obtain methyl phenyl silicone oil;

[0011] wherein the first catalyst and the second catalyst are each independently selected from tetramethylammonium hydroxide silanol salt and potassium hydroxide silanol salt, the amount of the first catalyst is 20-1000 ppm based on the total weight of the phenyldialkoxysilane and the chain extender, and the amount of the second catalyst is (1-10):1 relative to the amount of the first catalyst;

[0012] and wherein the method further comprises: adding an end-capping agent before the hydrolysis reaction in step S100 or before the addition of the second catalyst in step S200.

[0013] In the present application, a specific phenyldialkoxysilane and a chain extender are used as raw materials, a hydrolysis reaction is carried out in the presence of water and a specific first catalyst, and without the operations such as water washing, neutralization and filtration, after warming, the hydrolysate after low-molecular-weight-removing is directly subjected to polycondensation in the presence of a second catalyst to obtain methyl phenyl silicone oil. The method of the present application reduces the process for preparing methyl phenyl silicone oil to two processes of hydrolysis and polycondensation, realizes the effect of preparing methyl phenyl silicone oil by one-pot method, and has the advantages of low production equipment investment cost.

[0014] According to the method provided by the present application, the properties of the methyl phenyl silicone oil, in particular the refractive index, can be adjusted by controlling the phenyldialkoxysilane and the chain extender. Meanwhile, the viscosity of the methyl phenyl silicone oil can also be adjusted by controlling the amount of the chain extender. Generally, the amount of the chain extender is positively correlated with the viscosity of the methyl phenyl silicone oil.

[0015] In some embodiments, the phenyldialkoxysilane includes diphenyldimethoxysilane or a mixture of methylphenyldimethoxysilane and diphenyldimethoxysilane. In the mixture of methylphenyldimethoxysilane and diphenyldimethoxysilane, the weight ratio of methylphenyldimethoxysilane to diphenyldimethoxysilane can be (0.5-2):1, preferably (0.8-1.2):1.

[0016] In some embodiments, the weight ratio of the phenyldialkoxysilane to the chain extender can be (0.1-5):1. For example, the weight ratio of the phenyldialkoxysilane to the chain extender can be 0.1:1, 0.2:1, 0.4:1, 0.5:1, 0.8:1, 1:1, 1.2:1, 1.5:1, 2:1, 2.5:1, 3:1, 4:1, 5:1, or a range thereof. In some specific embodiments, the weight ratio of the phenyldialkoxysilane to the chain extender can be (0.4-3):1, preferably (0.4-2.5):1.

[0017] According to the method provided by the present invention, the dimethylcyclosiloxane can be octamethylcyclotetrasiloxane (D4) or a dimethylsiloxane mixed ring (DMC), in particular a mixture of octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane (D5), and dodecamethylcyclohexasiloxane (D6). The present invention has no particular restrictions on the ratio of D4, D5, and D6 in the dimethylsiloxane mixed ring, and DMC available in the art can be used.

[0018] According to the method provided by the present invention, the viscosity of the α,ω-dihydroxypolydimethylsiloxane at 25° C. is 50 to 140 mPa.s, for example, 80 to 120 mPa.s.

[0019] According to the method provided by the present invention, in step S100, the molar ratio of water to phenyldialkoxysilane is (0.1-0.3):1, preferably (0.15-0.25):1.

[0020] According to the method provided by the present invention, the amount of the first catalyst may be 40 to 500 ppm, preferably 40 to 300 ppm, based on the total weight of the phenyldialkoxysilane and the chain extender.

[0021] According to the method provided by the present invention, the end-capping agent is selected from hexamethyldisiloxane (CAS No. 107-46-0), low-viscosity methyl silicone oil, 1,3-dimethyl-1,1,3,3-tetraphenyldisiloxane (CAS No. 807-28-3), 1,1,5,5-tetraphenyl-1,3,3,5-tetramethyltrisiloxane (CAS No. 3982-82-9) and 1,3-diphenyl-1,1,3,3-tetramethyldisiloxane (CAS No. 56-33-7).

[0022] In the present invention, the viscosity of the low viscosity methyl silicone oil at 25°C can be 1 to 10 mm 2 / s, preferably 5 to 8 mm 2 / s. According to the method provided by the present invention, the viscosity of the methylphenyl silicone oil can be adjusted by controlling the amount of the end-capping agent. Generally, the amount of the end-capping agent is negatively correlated with the viscosity of the methylphenyl silicone oil.

[0023] In some embodiments, based on 100 parts by weight of the total amount of phenyldialkoxysilane and the chain extender, the amount of the end-capping agent is 1 to 20 parts by weight, preferably 1.5 to 17.5 parts by weight.

[0024] According to the method provided by the present invention, the conditions for the hydrolysis reaction in step S100 include: a temperature of 50 to 70° C.; and / or a time of 1 to 12 hours, preferably 1 to 3 hours.

[0025] According to the method provided by the present invention, the conditions for the first degassing treatment in step S100 include: a vacuum degree of -0.03 to -0.099 MPa, preferably -0.03 to -0.08 MPa; and a time of 1 to 12 hours, preferably 1 to 3 hours.

[0026] The vacuum level used in the first desulfurization treatment in step S100 can be determined based on the type of chain extender. In some embodiments, the chain extender is dimethylcyclosiloxane, and the vacuum level used in the first desulfurization treatment can be -0.03 to -0.04 MPa. This vacuum level prevents dimethylcyclosiloxanes, such as D4 or DMC, from being removed along with methanol.

[0027] According to the method provided by the present invention, in step S100, after hydrolysis, the methanol produced in the hydrolysis process can be removed through a first dehydrogenation treatment (concentration), thereby pushing the equilibrium of the reaction to the right.

[0028] In the present invention, the following method can be used to determine whether the hydrolysis and the first deoxidation treatment in step S100 have been completed:

[0029] Mode I: No more bubbles emerge in the reactor, and no more liquid drops flow out of the condenser tube used to condense the gas removed by the first degassing treatment; and / or,

[0030] Method II: Take a sample from the reactor, mix the sample with water in a mass ratio of 1:1, and let it stand for 10 minutes. If there is no white turbidity in the oil layer after oil-water separation.

[0031] According to the method provided by the present invention, the hydrolysis reaction and the first deoxidation treatment in step S100 can be performed once or repeatedly, for example, 2 to 5 times, preferably 2 to 3 times.

[0032] In some embodiments, water may be added during the second or subsequent hydrolysis reactions and the first desulfurization treatment, with the weight ratio of the added water to the phenyldialkoxysilane being (0.1-0.3):1.

[0033] According to the method provided by the present invention, the dosage of the second catalyst can be determined based on the reaction rate (viscosity growth rate). For example, after adding the second catalyst, if the reaction rate is slow, additional second catalyst can be added, for example, at a dosage of 50-60 ppm. Specifically, if the viscosity does not increase significantly, it is considered that no additional catalyst is needed. Otherwise, it is considered that the previously added second catalyst dosage is insufficient, resulting in a slow reaction rate.

[0034] In some embodiments, the amount of the second catalyst is 50 to 1000 ppm, preferably 50 to 500 ppm, based on the total weight of the phenyldialkoxysilane and the chain extender.

[0035] According to the method provided by the present invention, the ratio of the amount of the first catalyst to the amount of the second catalyst can be 1:1, 1.2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1 or a range thereof, preferably (1.2 to 6):1.

[0036] According to the method provided by the present invention, the amount of the first catalyst used is the same as the type of the second catalyst. For example, the first catalyst and the second catalyst are both alkaline or neutral.

[0037] According to the method provided by the present invention, the reaction conditions in step S200 include: a reaction temperature of 90 to 160° C.; and / or a reaction time of 1 to 10 hours, preferably 2 to 6 hours.

[0038] According to the method provided by the present invention, in step S200, the reaction endpoint can be determined and the reaction can be terminated by the following method: sampling is performed every hour, and the viscosity of the sample is tested using a kinematic viscometer or a Brookfield rotational viscometer. When the viscosity increase of two consecutive samples is less than 3%, the reaction endpoint is reached.

[0039] According to the method provided by the present invention, in step S200, the reaction is terminated by the following method:

[0040] S210, heating to 150°C to carry out catalyst destruction reaction for 1 to 2 hours; or

[0041] S220. Add neutralizer and neutralize for 1 to 2 hours.

[0042] In some embodiments, the neutralizing agent is selected from siloxane phosphates, strong base and weak acid salts such as K2CO3 and Na2CO3.

[0043] In some specific embodiments, the first and second catalysts are tetramethylammonium hydroxide siliconate. The reaction conditions in step S200 include a temperature of 90-120°C, a reaction time of 5-6 hours, and a catalyst decomposition reaction at 150°C for 1-2 hours. Furthermore, the reaction in step S200 can be performed under vacuum to accelerate the reaction. Preferably, the vacuum level can be -0.04 to -0.05 MPa.

[0044] In some specific embodiments, the first and second catalysts are potassium hydroxide siliconate, and the neutralizing agent is a siloxane phosphate. The reaction conditions in step S200 include a temperature of 140-160°C and a reaction time of 6-10 hours. The reaction is terminated by adding the neutralizing agent and neutralizing at 40-150°C for 1-2 hours. Furthermore, after 1-2 hours of reaction in step S200, vacuuming can be performed to accelerate the reaction. Preferably, the vacuum level can be -0.04 to -0.05 MPa.

[0045] In some specific embodiments, the weight ratio of the neutralizer to the total weight of the first catalyst and the second catalyst is 1.5 to 4:1, preferably 2 to 3:1.

[0046] According to the method provided by the present invention, the conditions for the second desulfurization treatment in step S300 include: temperature of 160 to 180° C.; vacuum degree of -0.05 to -0.099 MPa; and time of 1 to 4 hours.

[0047] In the present invention, the second denitrification treatment in step S300 can be performed under stirring conditions or nitrogen blowing conditions, or can be performed directly, and the present invention has no special limitation on this.

[0048] According to the method provided by the present invention, step S300 may further include filtering the product of the second desulfurization treatment to obtain transparent methylphenyl silicone oil. In the present invention, diatomaceous earth or activated carbon may be used for filtration.

[0049] According to the method provided by the present invention, the structure of the methylphenyl silicone oil can be as shown in Formula I:

[0050]

[0051] In Formula I, Ra and Rb are each independently a capping agent residue, and x≥1, y≥0, z≥0, and y+z≥1.

[0052] Formula I exemplarily shows that the methylphenyl silicone oil prepared by the present invention can contain dimethylsiloxane chain link (repeating unit), methylphenylsiloxane chain link (repeating unit), diphenylsiloxane chain link (repeating unit), but does not mean that these three repeating units are arranged in the order shown. The present invention has no particular requirements on the order (position) of the three kinds of chain links (repeating units). Usually, the methylphenyl silicone oil prepared by the inventive method can be a mixture of different arrangement structures.

[0053] For example, the methylphenyl silicone oil shown in formula I also includes the structure shown in formula II or formula III:

[0054]

[0055] In Formula II and III, Ra and Rb are each independently a capping agent residue, x≥1, y≥0, z≥0, y+z≥1. In some embodiments, Ra and Rb are selected from:

[0056]

[0057]

[0058] According to the method provided by the present invention, the viscosity of the methylphenyl silicone oil at 25°C can be 40 to 20,000 mm 2 / s.

[0059] In addition, the methylphenyl silicone oil prepared by the method of the present invention can be a colorless or light yellow liquid with a chromaticity of less than 60 hazen.

[0060] The method of the present invention has the following advantages:

[0061] (1) In the prior art, dilute hydrochloric acid is used as a hydrolysis catalyst, which introduces water-soluble hydrogen ions and chloride ions that need to be removed by water washing. However, a small amount of hydrogen ions will still remain after washing, which generally requires a neutralization process, which is time-consuming. For example, excessive ammonium bicarbonate is added for neutralization. After neutralization, the excess ammonium bicarbonate is removed by heating.

[0062] In comparison, in the method of the present invention, a specific phenyldialkoxysilane and a chain extender are used as raw materials, and a hydrolysis reaction is carried out in the presence of water and a specific first catalyst. No operations such as water washing, neutralization, and filtration are required. After heating, the hydrolyzate after desulfurization is directly polycondensed in the presence of a second catalyst to prepare methylphenyl silicone oil. As a result, the process of preparing methylphenyl silicone oil is reduced to the two processes of hydrolysis and polycondensation, achieving the effect of preparing methylphenyl silicone oil by a "one-pot method", which has the advantages of low investment cost of production equipment.

[0063] (2) In the method of the present invention, tetramethylammonium hydroxide siliconate or potassium hydroxide siliconate is used as the first catalyst and the second catalyst, and is miscible with the chain extender, the end-capping agent, and the phenyldialkoxysilane. The hydrolysis process of step S100 does not require the use of toluene or other organic solvents, and does not require repeated water washing and standing stratification steps after the hydrolysis. The hydrolysis, the first desulfurization treatment, and the polycondensation process are all completed in the same reactor. The present invention only requires a single reactor to achieve the effects of the hydrolysis, concentration, and polycondensation processes, and has the advantages of simple production, safe production, no methoxy residue, and environmental protection, low equipment investment, and high production efficiency.

[0064] (3) The methylphenyl silicone oil prepared by the method of the present invention can be used as / as a raw material for vacuum diffusion pump oil, high-temperature heating oil, additives in the daily chemical industry, softening finishing agents in the textile industry, lubricating oils in the electronic and electrical industries, self-penetrating liquid silicone rubber, gas chromatography carriers, high-temperature lubricating oils, greases, and thermal greases, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 The methylphenyl silicone oil prepared in Example 1 1 H-NMR spectrum;

[0066] Figure 2 The methylphenyl silicone oil prepared in Example 2 1 H-NMR spectrum. DETAILED DESCRIPTION

[0067] The raw materials involved in each embodiment and comparative example of the present invention include:

[0068] Methylphenyldimethoxysilane, diphenyldimethoxysilane, Jiangxi Hongbai New Materials Co., Ltd.;

[0069] Tetramethylammonium hydroxide siliconate catalyst, 3% content, Jiangxi Bluestar Xinghuo Silicone Co., Ltd.;

[0070] Potassium hydroxide siliconate, 15% content, Jiangxi Bluestar Xinghuo Silicone Co., Ltd.;

[0071] Silicon-based phosphate, 15% content, Jiangxi Bluestar Xinghuo Silicone Co., Ltd.;

[0072] D4 and DMC, Jiangxi Bluestar Xinghuo Silicone Co., Ltd.;

[0073] Low viscosity α,ω-dihydroxy polydimethylsiloxane, Jiangxi Lanxing Xinghuo Silicone Co., Ltd.;

[0074] 1,3-Dimethyl-1,1,3,3-tetraphenyldisiloxane, Anhui Aiyota Silicone Oil Co., Ltd.;

[0075] 1,1,5,5-Tetraphenyl-1,3,3,5-tetramethyltrisiloxane, Dow Corning.

[0076] In addition, the reagents or instruments used in this application that do not indicate the manufacturer can be purchased through regular channels or made by yourself.

[0077] Example 1

[0078] (1) Add 127.4 g of methylphenyldimethoxysilane, 122.2 g of diphenyldimethoxysilane, 100 g of octamethylcyclotetrasiloxane (D4) and 60 g of 1,1,5,5-tetraphenyl-1,3,3,5-tetramethyltrisiloxane to a reactor and heat to 50° C. to obtain a premix;

[0079] (2) adding 51.84 g of deionized water and 0.683 g of tetramethylammonium hydroxide silicon alkoxide (ammonia gel) catalyst to the premix, and hydrolyzing for 3 h to obtain a hydrolysis reaction mixture; vacuuming the hydrolysis reaction mixture for 1 h, wherein the vacuum degree is -0.03 MPa, to obtain a hydrolyzate;

[0080] (3) heating to 90°C, adding 4.1 g of tetramethylammonium hydroxide silicon alkoxide catalyst to the hydrolyzate, polycondensing for 5 h, heating to 150°C, breaking the catalyst and reacting for 1 h to obtain a polycondensate;

[0081] (4) Raise the temperature to 180°C, evacuate to below -0.095 MPa, and degas for 1 hour to obtain methylphenyl silicone oil.

[0082] Example 2

[0083] (1) 232 g of diphenyl dimethoxysilane, 94 g of octamethylcyclotetrasiloxane (D4) and 17 g of 1,3-dimethyl-1,1,3,3-tetraphenyl disiloxane were added into a reactor, and the temperature was raised to 70°C to obtain a premix;

[0084] (2) 41.08 g of deionized water and 0.573 g of tetramethylammonium hydroxide silanol catalyst were added into the premix, and hydrolysis was carried out for 3 h to obtain a hydrolysis reaction mixture; the hydrolysis reaction mixture was vacuumized to remove low-boiling substances for 1 h, wherein the vacuum degree was -0.03 MPa, to obtain a hydrolysate;

[0085] (3) The temperature was raised to 90°C, 3.43 g of tetramethylammonium hydroxide silanol catalyst was added into the hydrolysate, and polycondensation was carried out for 5 h; the temperature was raised to 150°C, and the medium was broken for 1 h to obtain a polycondensate;

[0086] (4) The temperature was raised to 180°C, vacuumization was carried out to below -0.095 MPa, and low-boiling substances were removed for 1 h to obtain a methylphenyl silicone oil.

[0087] Example 3

[0088] (1) 127.4 g of methylphenyl dimethoxysilane, 122.2 g of diphenyl dimethoxysilane, 100 g of octamethylcyclotetrasiloxane (D4) and 60 g of 1,1,5,5-tetraphenyl-1,3,3,5-tetramethyltrisiloxane were added into a reactor, and the temperature was raised to 60°C to obtain a premix;

[0089] (2) 46.84 g of deionized water and 0.533 g of KOH silanol catalyst were added, and hydrolysis was carried out for 3 h to obtain a hydrolysis reaction mixture; the hydrolysis reaction mixture was vacuumized to remove low-boiling substances for 1 h, wherein the vacuum degree was -0.03 MPa, to obtain a hydrolysate;

[0090] (3) The temperature was raised to 160°C, 0.667 g of KOH silanol catalyst was added into the hydrolysate, and polycondensation was carried out for 5 h; 3.6 g of silicon-based phosphate was added, and neutralization was carried out for 1 h to obtain a polycondensate.

[0091] (4) The temperature was raised to 180°C, vacuumization was carried out to below -0.095 MPa, and low-boiling substances were removed for 1 h to obtain a methylphenyl silicone oil.

[0092] Example 4

[0093] (1) 53 g of diphenyl dimethoxysilane, 120 g of α,ω-dihydroxypolydimethylsiloxane with a viscosity of 96 mm 2 / s, and 3 g of methyl silicone oil with a viscosity of 5 mm 2 / s were added into a reactor, and the temperature was raised to 50°C to obtain a premix;

[0094] (2) adding 9.37 g of deionized water and 0.047 g of KOH silicon alkoxide catalyst to the premix, hydrolyzing for 3 h to obtain a hydrolysis reaction mixture, and vacuuming the hydrolysis reaction mixture for 1 h, wherein the vacuum degree is -0.04 MPa, to obtain a hydrolyzate;

[0095] (3) heating to 160° C., adding 0.067 g of KOH silicon alkoxide catalyst to the hydrolyzate, and polycondensing for 5 h; adding 0.34 g of silicon-based phosphate, and neutralizing for 1 h to obtain a polycondensate;

[0096] (4) Raise the temperature to 180°C, evacuate to below -0.095 MPa, and degas for 1 hour to obtain methylphenyl silicone oil.

[0097] Comparative Example 1

[0098] (1) Add 127.4 g of methylphenyldimethoxysilane and 122.2 g of diphenyldimethoxysilane to a reactor, raise the temperature to 70° C. by condensation reflux, and continue to add 30 g of toluene to obtain a premix;

[0099] (2) Slowly drop 5 g of 7‰ hydrochloric acid and 50 g of deionized water into the reactor, raise the temperature to 80°C, and carry out the hydrolysis reaction for 5 h;

[0100] (3) Stop heating, transfer the material in the reactor of step (2) to a separatory funnel, let it stand for 5 hours, separate the layers, and take out the lower layer of hydrolyzate;

[0101] (4) The hydrolyzed liquid from step (3) was transferred to a water washing kettle and washed five times, and then 2 g of 1% ammonia solution was added, and the temperature was raised to 30°C and neutralized for 1 hour;

[0102] (5) After the temperature reaches 60°C, start the vacuum pump and perform degassing at a vacuum degree of -0.08 MPa for 1 hour;

[0103] (6) The material of step (5) was transferred to a polycondensation reactor, heated to 90°C, 100g of D4 (tetracyclic form of octamethylsiloxane) and 60g of 1,1,5,5-tetraphenyl-1,3,3,5-tetramethyltrisiloxane were added, and then 4.1g of tetramethylammonium hydroxide silicon alkoxide was added. The reaction was carried out for 5h, and the temperature was raised to 150°C. The catalyst was broken and reacted for 1h to obtain a polycondensate;

[0104] (7) Raise the temperature to 180°C, evacuate to below -0.095 MPa, and degas for 1 hour to obtain methylphenyl silicone oil.

[0105] Comparative Example 2

[0106] (1) Add 232 g of diphenyldimethoxysilane to a reactor, raise the temperature to 70° C. by condensation reflux, and continue to add 30 g of toluene to obtain a premix;

[0107] (2) Slowly drop 5 g of 7‰ hydrochloric acid and 40 g of deionized water into the reactor, raise the temperature to 80°C, and carry out the hydrolysis reaction for 5 h;

[0108] (3) Stop heating, transfer the material in the reactor of step (2) to a separatory funnel, let it stand for 5 hours, separate the layers, and take out the lower layer of hydrolyzate;

[0109] (4) The hydrolyzed solution from step (3) was transferred to a water washing kettle and washed five times, then 2 g of 1% ammonia water was added, and the temperature was raised to 30°C and neutralized for 1 hour;

[0110] (5) After heating to 60°C, degassing was performed at a vacuum of -0.08 MPa for 1 h;

[0111] (6) The material of step (5) was transferred to a polycondensation reactor, heated to 90°C, 94g of D4 (tetracyclic ring of octamethylsiloxane) and 17g of 1,3-dimethyl-1,1,3,3-tetraphenyldisiloxane were added, and then 3.43g of tetramethylammonium hydroxide silicon alkoxide was added. The reaction was carried out for 5h, and the temperature was raised to 150°C. The catalyst was broken and reacted for 1h to obtain a polycondensate;

[0112] (7) Raise the temperature to 180°C, evacuate to below -0.095 MPa, and degas for 1 hour to obtain methylphenyl silicone oil.

[0113] Comparative Example 3

[0114] (1) Add 127.4 g of methylphenyldimethoxysilane and 122.2 g of diphenyldimethoxysilane to a reactor, raise the temperature to 70° C. by condensation reflux, and continue to add 30 g of toluene to obtain a premix;

[0115] (2) Slowly drop 5 g of 7‰ hydrochloric acid and 43 g of deionized water into the reactor, raise the temperature to 80°C, and carry out the hydrolysis reaction for 5 h;

[0116] (3) Stop heating, transfer the material in the reaction kettle of step (2) to a separatory funnel, let it stand for 5 hours, separate the layers, and take out the lower layer of hydrolyzate;

[0117] (4) The hydrolyzed solution from step (3) was transferred to a water washing kettle and washed five times, then 2 g of 1% ammonia water was added, and the temperature was raised to 30°C and neutralized for 1 hour;

[0118] (5) After heating to 60°C, degassing was performed at a vacuum of -0.08 MPa for 1 h;

[0119] (6) The material of step (5) was transferred to a condensation kettle, warmed to 160°C, 100 g of D4 (tetra ring of octamethylsiloxane) and 60 g of 1,1,5,5-tetraphenyl-1,3,3,5-tetramethyltrisiloxane were added, and then 0.667 g of KOH silanol catalyst was added, and reacted for 5 h;

[0120] (7) 2.0 g of phosphosiloxane ester was added, and neutralized for 1 h;

[0121] (8) Warmed to 180°C, vacuumed to below -0.095 MPa, and de- lowed for 1 h to obtain a methylphenyl silicone oil.

[0122] Comparative Example 4

[0123] (1) 53 g of diphenyldimethoxysilane was added to a reactor, warmed to 70°C using a condensation reflux method, and 7 g of toluene was continuously added to obtain a premix;

[0124] (2) 1.5 g of 7 ‰ hydrochloric acid and 9.38 g of deionized water were slowly dripped into the reactor, the temperature was raised to 80°C, and a hydrolysis reaction was carried out for 5 h;

[0125] (3) The heating was stopped, and the material in the reactor of step (2) was transferred to a separatory funnel, and after standing for 5 h, the layers were separated, and the lower layer of hydrolysis liquid was taken out;

[0126] (4) The hydrolysis liquid of step (3) was transferred to a water washing kettle and washed with water for 5 times, 0.5 g of 1% ammonia solution was further added, and warmed to 30°C, and neutralized for 1 h;

[0127] (5) De- lowed treatment under a vacuum degree of -0.08 MPa for 1 h;

[0128] (6) Condensation reaction: the material of step (5) was transferred to a condensation kettle, warmed to 160°C, 120 g of α,ω-dihydroxypolydimethylsiloxane with a viscosity of 96 mm 2 / s and 3 g of methyl silicone oil with a viscosity of 5 mm 2 / s were added, and then 0.067 g of KOH silanol catalyst was added, and reacted for 5 h;

[0129] (7) 0.20 g of phosphosiloxane ester was added, and neutralized for 1 h;

[0130] (8) Warmed to 180°C, vacuumed to below -0.095 MPa, and de- lowed for 1 h to obtain a methylphenyl silicone oil.

[0131] Comparative Example 5

[0132] (1) Add 127.4 g of methylphenyldimethoxysilane, 122.2 g of diphenyldimethoxysilane, 100 g of octamethylcyclotetrasiloxane (D4) and 60 g of 1,1,5,5-tetraphenyl-1,3,3,5-tetramethyltrisiloxane to a reactor and heat to 50° C. to obtain a premix;

[0133] (2) adding 0.683 g of tetramethylammonium hydroxide silicon alkoxide catalyst to the premix and reacting for 3 h to obtain a reaction mixture; evacuating the reaction mixture for 1 h, wherein the vacuum degree is -0.03 MPa, to obtain a reaction mixture;

[0134] (3) heating to 90°C, adding 4.1 g of tetramethylammonium hydroxide silicon alkoxide catalyst to the reaction mixture, polycondensing for 5 h, heating to 150°C, breaking the catalyst and reacting for 1 h to obtain a polycondensate;

[0135] (4) Raise the temperature to 180°C, evacuate to below -0.095 MPa, and degas for 1 hour to obtain methylphenyl silicone oil.

[0136] Comparative Example 6

[0137] (1) Add 127.4 g of methylphenyldimethoxysilane, 122.2 g of diphenyldimethoxysilane, 100 g of octamethylcyclotetrasiloxane (D4) and 60 g of 1,1,5,5-tetraphenyl-1,3,3,5-tetramethyltrisiloxane to a reactor and heat to 50° C. to obtain a premix;

[0138] (2) adding 51.84 g of deionized water and 4.783 g of tetramethylammonium hydroxide silicon alkoxide catalyst, and hydrolyzing for 3 h to obtain a hydrolysis reaction mixture; vacuuming the hydrolysis reaction mixture for 1 h, wherein the vacuum degree is -0.03 MPa, to obtain a hydrolyzate;

[0139] (3) Heating to 90°C, continuing the reaction for 5 h, then heating to 150°C, breaking the catalyst and reacting for 1 h to obtain a polycondensate;

[0140] (4) Raise the temperature to 180°C, evacuate to below -0.095 MPa, and degas for 1 hour to obtain methylphenyl silicone oil.

[0141] Comparative Example 7

[0142] (1) Add 127.4 g of methylphenyldimethoxysilane, 122.2 g of diphenyldimethoxysilane, 100 g of octamethylcyclotetrasiloxane (D4) and 60 g of 1,1,5,5-tetraphenyl-1,3,3,5-tetramethyltrisiloxane to a reactor and heat to 50° C. to obtain a premix;

[0143] (2) adding 51.84 g of deionized water and 3.189 g of tetramethylammonium hydroxide silicon alkoxide catalyst, and hydrolyzing for 3 h to obtain a hydrolysis reaction mixture; vacuuming the hydrolysis reaction mixture for 1 h, wherein the vacuum degree is -0.04 MPa, to obtain a hydrolyzate;

[0144] (3) heating to 90°C, adding 1.594 g of tetramethylammonium hydroxide silicon alkoxide catalyst to the hydrolyzate, polycondensing for 4 h, heating to 150°C, breaking the catalyst and reacting for 1 h to obtain a polycondensate;

[0145] (4) Raise the temperature to 180°C, evacuate to below -0.095 MPa, and degas for 1 hour to obtain methylphenyl silicone oil.

[0146] Product Characterization

[0147] The product was characterized using the AVANCE AV400MHZ nuclear magnetic resonance instrument from Bruker, Germany. Figure 1 The 1H-NMR spectrum of the sample of Example 1 is shown. Figure 2 The sample of Example 2 is shown 1 H-NMR spectrum. Figures 1-2 It can be seen that the target product was obtained, wherein the sample of Example 1 has the NMR information of the H atom of the methyl group of the methylphenyl chain segment when δ is between 0.2 and 0.6, while the product of Example 2 does not contain this NMR information. 1 The H-NMR spectrum results showed that the target products were also prepared in Examples 3 and 4.

[0148] The refractive index, kinematic viscosity, and chromaticity of each example product were measured, and the results are shown in Table 1. In addition, the quality was evaluated by mixing the sample with deionized water at a weight ratio of 1:1 for 30 minutes, then letting it stand for 30 minutes, and observing whether it was turbid after separation. The results are shown in Table 1.

[0149] Table 1 Properties of methylphenyl silicone oil

[0150]

[0151]

[0152] In conjunction with Table 1, it can be seen from Examples 1 to 4 and Comparative Examples 1 to 4 that the method of the present invention does not require operations such as washing, neutralization, and filtration. After heating, the hydrolyzate after desulfurization is directly polycondensed in the presence of a second catalyst to prepare methylphenyl silicone oil. Thus, the process of preparing methylphenyl silicone oil is reduced to two processes, hydrolysis and polycondensation, and the number of material transfers is significantly reduced, achieving the effect of preparing methylphenyl silicone oil by a "one-pot method" and having the characteristic of low production equipment investment cost.

[0153] Combining Example 1 and Comparative Example 5, it can be seen that when no water is added, hydrolysis is basically not carried out in step (2), the polycondensation in step (3) is incomplete, the sample viscosity is low, and after mixing and stratification with water, it becomes turbid, there are a large number of small molecules, and the chroma is high; when the catalyst is added at a ratio of 2:1 or more (Comparative Examples 6 and 7), the hydrolysis rate is too fast, gel appears after polycondensation, and even precipitation requires filtration, and after mixing and stratification with water, it becomes turbid, there are a large number of small molecules, and the chroma is high.

[0154] The above is a description of the embodiments of the present invention. The above description of the disclosed embodiments will enable professionals in the field to implement or use the present invention. Various modifications to these embodiments will be apparent to professionals in the field. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but should conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing methylphenyl silicone oil by a one-pot process, wherein: The method comprises the following steps: S100, hydrolyzing a phenyldialkoxysilane selected from methylphenyldimethoxysilane and diphenyldimethoxysilane and a chain extender selected from dimethylcyclosiloxane and α,ω-dihydroxypolydimethylsiloxane at a temperature of 40 to 90° C. in the presence of water and a first catalyst to obtain a hydrolysis reaction mixture, and performing a first desulfurization treatment on the hydrolysis reaction mixture to obtain a hydrolyzate; S200, adding a second catalyst to the hydrolyzate, reacting at 70-160° C., and terminating the reaction to obtain a polycondensate; S300, subjecting the polycondensate to a second desulfurization treatment to obtain methylphenyl silicone oil; The first catalyst and the second catalyst are each independently selected from tetramethylammonium hydroxide siliconate and potassium hydroxide siliconate, and the amount of the first catalyst is 20-1000 ppm based on the total weight of the phenyldialkoxysilane and the chain extender, and the amount of the second catalyst is in a ratio of (1-10):1 to the amount of the first catalyst; And wherein the method further comprises: adding a capping agent before the hydrolysis reaction in step S100 or before adding the second catalyst in step S200; The weight ratio of the phenyldialkoxysilane to the chain extender is (0.1-5):

1.

2. The method according to claim 1, wherein The phenyldialkoxysilane includes diphenyldimethoxysilane or a mixture of methylphenyldimethoxysilane and diphenyldimethoxysilane; And / or, the dimethylcyclosiloxane is octamethylcyclotetrasiloxane or a dimethylsiloxane mixed ring body; and / or, the viscosity of the α,ω-dihydroxypolydimethylsiloxane at 25° C. is 50 to 140 mPa.s; And / or, the weight ratio of the phenyldialkoxysilane to the chain extender is (0.4-3):

1.

3. The method according to claim 2, wherein: In the mixture of methylphenyldimethoxysilane and diphenyldimethoxysilane, the weight ratio of methylphenyldimethoxysilane to diphenyldimethoxysilane is (0.5-2):

1.

4. The method according to claim 2 or 3, wherein: The dimethylcyclosiloxane is a mixture of octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane and dodecamethylcyclohexasiloxane.

5. The method according to claim 1 or 2, wherein: In the mixture of methylphenyldimethoxysilane and diphenyldimethoxysilane, the weight ratio of methylphenyldimethoxysilane to diphenyldimethoxysilane is (0.8-1.2).

6. The method according to claim 1 or 2, wherein: The viscosity of the α,ω-dihydroxypolydimethylsiloxane at 25° C. is 80-120 mPa·s.

7. The method according to claim 1 or 2, wherein: The weight ratio of the phenyldialkoxysilane to the chain extender is (0.4-2.5):

1.

8. The method according to claim 1 or 2, wherein: In step S100, the molar ratio of water to phenyldialkoxysilane is (0.1-0.3):

1.

9. The method according to any one of claims 1 to 3, wherein The end-capping agent is selected from hexamethyldisiloxane, low viscosity methyl silicone oil, 1,3-dimethyl-1,1,3,3-tetraphenyldisiloxane, 1,1,5,5-tetraphenyl-1,3,3,5-tetramethyltrisiloxane and 1,3-diphenyl-1,1,3,3-tetramethyldisiloxane; And / or, based on 100 parts by weight of the total amount of phenyldialkoxysilane and the chain extender, the amount of the end-capping agent is 1 to 20 parts by weight.

10. The method according to claim 9, wherein: The viscosity of the low viscosity methyl silicone oil at 25°C is 1-10 mm 2 / s.

11. The method according to claim 9, wherein Based on 100 parts by weight of the total amount of phenyldialkoxysilane and the chain extender, the amount of the end-capping agent is 1.5 to 17.5 parts by weight.

12. The method according to claim 10, wherein: The viscosity of the low viscosity methyl silicone oil at 25°C is 5-8 mm 2 / s.

13. The method according to any one of claims 1 to 3, wherein The conditions for the hydrolysis reaction in step S100 include: a temperature of 50-70° C.; and / or a time of 1-12 h.

14. The method according to claim 13, wherein The conditions for the hydrolysis reaction in step S100 include: a time of 1 to 3 hours.

15. The method according to any one of claims 1 to 3, wherein The conditions of the first degassing treatment in step S100 include: a vacuum degree of -0.03 to -0.099 MPa; and a time of 1 to 12 hours.

16. The method according to claim 15, wherein The conditions of the first degassing treatment in step S100 include: a vacuum degree of -0.03 to -0.08 MPa; and a time of 1 to 3 hours.

17. The method according to any one of claims 1 to 3, wherein Based on the total weight of phenyldialkoxysilane and chain extender, the amount of the first catalyst is 40 to 500 ppm; and / or, based on the total weight of the phenyldialkoxysilane and the chain extender, the amount of the second catalyst is 50 to 1000 ppm; And / or, the ratio of the amount of the second catalyst to the amount of the first catalyst is (1.2-6):

1.

18. The method according to any one of claims 1 to 3, wherein Based on the total weight of phenyldialkoxysilane and chain extender, the amount of the first catalyst is 40 to 300 ppm; And / or, based on the total weight of the phenyldialkoxysilane and the chain extender, the amount of the second catalyst is 50 to 500 ppm.

19. The method according to any one of claims 1 to 3, wherein In step S200, the reaction is terminated by: S210, heating to 150°C to carry out catalyst decomposition reaction for 1-2 hours; or S220, add neutralizer, neutralize for 1~2h; The neutralizing agent is selected from silicone phosphate; The weight ratio of the neutralizer to the total weight of the first catalyst and the second catalyst is 1.5-4:

1.

20. The method according to claim 19, wherein The weight ratio of the neutralizer to the total weight of the first catalyst and the second catalyst is 2-3:

1.

21. The method according to any one of claims 1 to 3, wherein The conditions of the second degassing treatment in step S300 include: a temperature of 160-180° C.; a vacuum degree of -0.05-0.099 MPa; and a time of 1-4 hours.

22. The method according to any one of claims 1 to 3, wherein The viscosity of the methylphenyl silicone oil at 25°C is 40-20000 mm 2 / s.

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