A kind of low ring body content epoxy silicone oil and preparation method thereof

Abstract

The invention belongs to the technical field of silicone oil, and discloses a low-ring body content epoxy silicone oil and a preparation method thereof. A cyclosiloxane monomer and a disiloxane double head are used as raw materials, trifluoromethanesulfonic acid is used in combination with a hindered amine as a catalyst system, and a hydrogen-based silicone oil is generated by ring-opening polymerization, and then the epoxy silicone oil is obtained by a hydrosilylation reaction with allyl glycidyl ether. In the ring-opening polymerization process of cyclosiloxane, trifluoromethanesulfonic acid and a hindered amide are used as a catalyst system to avoid the "backbiting" of the molecular chain of the generated organosilicon trifluoromethanesulfonic acid silicon alcohol salt to generate cyclosiloxane and macrocyclic siloxane by-products, greatly reducing the ring body content of cyclosiloxane and the like in the silicone oil product, and greatly improving the bio-friendliness and environmental safety of the silicone oil product. The present invention adopts a catalyst composite method to avoid catalyst poisoning caused by hindered amides, and successfully realizes the hydrosilylation reaction to prepare epoxy silicone oil. The reaction conditions of the present invention are mild, the raw materials are cheap and easy to obtain, the preparation process is simple, and it is suitable for industrial production.

Description

Technical Field

[0001] The invention relates to a method for preparing epoxy silicone oil, in particular to a method for preparing epoxy silicone oil with low ring body content, and specifically belongs to the field of silicone oil preparation in organic silicon materials. Background Art

[0002] There are usually two technical routes for synthesizing linear polysiloxanes such as silicone oil: one is to use cyclosiloxane monomers as raw materials and prepare them by ring-opening equilibrium polymerization; the other is to use a mixture of oligosiloxanes or cyclosiloxanes as raw materials and prepare them by equilibrium polymerization. In the synthesis process, either protonic acid or base can be used as a catalyst. Commonly used protonic acids are concentrated sulfuric acid, perchloric acid and trifluoromethanesulfonic acid. Among them, trifluoromethanesulfonic acid, as a superacid, has the advantages of strong acidity and low dosage when catalyzing the synthesis of silicone oil. The most commonly used alkaline catalysts are sodium hydroxide, potassium hydroxide, tetramethylhydroxylamine, etc., or alkaline gel synthesized from alkali and silicone oil.

[0003] However, no matter whether acid or base is used to catalyze the synthesis of silicone oil, and no matter whether the raw materials used are cyclosiloxane or oligomeric linear polysiloxane, due to the competitive reaction between the linear polysiloxane chain and cyclosiloxane, the prepared silicone oil product will inevitably generate macrocyclic byproducts, which are stable and eventually reach equilibrium with linear polysiloxane components of different molecular weights. Since the European Commission formally revised the restrictions on the use of octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5) and dodecamethylcyclohexasiloxane (D6) in Annex XVII of (EC) No 1907 / 2006 (i.e. REACH Regulation), the revision of this regulation will affect the use and limit of these three substances in products. The relevant products urgently need to reasonably adjust the production process to avoid risks. At present, the cyclic content of silicone oil products sold on the market is generally higher than 1000ppm, and some are even as high as 3000ppm.

[0004] Therefore, how to develop new processes to produce including but not limited to hydrogen-based silicone oil, methyl silicone oil, vinyl silicone oil, phenyl silicone oil, etc. is of great significance for silicone products to adapt to environmental protection and bio-friendliness requirements and expand the application areas of silicone industry products. Summary of the invention

[0005] The present invention aims at the problem of inevitable cyclization side reaction commonly existing in the current silicone oil synthesis and the high ring body content of the product obtained thereby, and discloses a method for preparing linear polysiloxane by catalysis of a trifluoromethanesulfonic acid / hindered amide catalyst system. The alkalinity of hindered amines, especially hindered amides, is greatly weakened, and the positive and negative ion pairs formed after the reaction with acid are not tightly bound, so they have catalytic activity. The present invention utilizes a protonic acid / hindered amide composite catalyst system to catalyze the ring opening of cyclosiloxane monomers. Under the action of a trace amount of water in the system, the catalyst system generates an enol intermediate; in addition, the generated trifluoromethanesulfonic acid silicon alcohol salt can be repeatedly circulated between active reaction species and dormant species, thereby avoiding the occurrence of molecular chain "biting back" of organic silicon active chains to generate cyclic byproducts, thereby obtaining a silicone oil product with a low ring body content.

[0006] The technical solution for achieving the purpose of the present invention is:

[0007] A method for preparing epoxy silicone oil with low cyclic content comprises the following steps: in the presence of a trifluoromethanesulfonic acid / hindered amide catalyst system, using siloxane and a capping agent as raw materials to carry out a ring-opening polymerization reaction to prepare hydrogen silicone oil; then using hydrogen silicone oil and an epoxy compound as raw materials to carry out a hydrosilylation reaction to prepare epoxy silicone oil with low cyclic content; the siloxane is dimethylcyclosiloxane, or dimethylcyclosiloxane and methylhydrogencyclosiloxane.

[0008] A method for preparing low-cyclic hydrogen-based silicone oil comprises the following steps: in the presence of a trifluoromethanesulfonic acid / hindered amide catalyst system, using siloxane and a capping agent as raw materials, performing a ring-opening polymerization reaction to prepare low-cyclic hydrogen-based silicone oil; the siloxane is dimethylcyclosiloxane, or dimethylcyclosiloxane and methylhydrogencyclosiloxane.

[0009] In the present invention, trifluoromethanesulfonic acid and hindered amide are reacted to obtain a trifluoromethanesulfonic acid / hindered amide catalyst system. Preferably, the hindered amide includes one or more of N,N'-dimethylformamide, N,N'-dimethylacetamide, and N,N'-methylphenylformamide; the weight ratio of trifluoromethanesulfonic acid to hindered amide is 1: (0.1-5), preferably 1: (0.5-3), more preferably 1: (0.8-2), and more preferably 1: (1-1.5); the reaction time is 0.1-12 hours, preferably 0.5-8 hours, more preferably 0.8-5 hours, and more preferably 1-3 hours; the reaction temperature is room temperature.

[0010] Furthermore, trifluoromethanesulfonic acid and hindered amide are reacted in a solvent to obtain a trifluoromethanesulfonic acid / hindered amide catalyst system; the solvent is an aromatic solvent, including toluene or any one of xylene; preferably, the weight ratio of the aromatic solvent, trifluoromethanesulfonic acid, and hindered amide is 100-200:1-2:0.2-5.

[0011] In the present invention, the siloxane is dimethylcyclosiloxane, or dimethylcyclosiloxane and methylhydrogencyclosiloxane. Preferably, the weight ratio of dimethylcyclosiloxane, methylhydrogencyclosiloxane and capping agent is 10000: (0-5000): (0.1-500); wherein the dimethylcyclosiloxane is any one of hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, or mixed cyclosiloxane (DMC, dimethylsiloxane mixed ring body).

[0012] In the present invention, the temperature of the ring-opening polymerization reaction is 50-100° C., and the time is 1-24 hours; preferably, the temperature of the ring-opening polymerization reaction is 50-80° C., and the time is 2-10 hours.

[0013] In the present invention, after the ring-opening polymerization reaction is completed, degassing is performed to obtain hydrogen-based silicone oil. During degassing, the material temperature is 80-135°C, preferably 90-110°C, the vacuum degree is 10-55 mmHg, preferably 30-50 mmHg, and the solvent and low molecular weight components are removed by distillation, and no liquid is distilled out.

[0014] In the present invention, during the hydrosilylation reaction, the catalyst is a platinum catalyst, and the epoxy compound is allyl glycidyl ether; the temperature of the hydrosilylation reaction is 70 to 105°C, and the time is 1 to 12 hours. Preferably, the platinum catalyst includes a Speier catalyst and a Karstedt's catalyst, and the weight ratio of the Speier catalyst to the Karstedt's catalyst is 1: (0.1 to 10), preferably 1: (0.5 to 5), more preferably 1: (0.8 to 2), and further preferably 1: (1 to 1.5).

[0015] In the present invention, the weight ratio of hydrogen-based silicone oil and epoxy compound is 100: (1-10); preferably, the weight ratio of hydrogen-based silicone oil and epoxy compound is 100: (1.5-5); further preferably, the weight ratio of hydrogen-based silicone oil and epoxy compound is 100: (2-4); further preferably, the weight ratio of hydrogen-based silicone oil and epoxy compound is 100: (2.2-3).

[0016] Preferably, the amount of platinum catalyst is 0.1‰ to 1% of the weight of the hydrogen-based silicone oil, preferably, the amount of platinum catalyst is 0.5‰ to 0.5% of the weight of the hydrogen-based silicone oil, further preferably, the amount of platinum catalyst is 0.1% to 0.5% of the weight of the hydrogen-based silicone oil, for example, the amount of platinum catalyst is 0.2% to 0.4% of the weight of the hydrogen-based silicone oil, and can be 0.3%; the catalyst is calculated by mass of Pt.

[0017] In the present invention, the reaction temperature of the hydrosilylation reaction is 60-105° C., and the reaction time is 1-12 hours; preferably, the reaction temperature of the hydrosilylation reaction is 70-90° C., and the reaction time is 2-6 hours.

[0018] The present invention discloses epoxy silicone oil with low cyclic content or hydrogen silicone oil with low cyclic content prepared according to the above preparation method, and further discloses the application of epoxy silicone oil with low cyclic content or hydrogen silicone oil with low cyclic content in the preparation of organosilicon materials.

[0019] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0020] 1. The trifluoromethanesulfonic acid and hindered amide catalytic system disclosed in the present invention, trifluoromethanesulfonic acid and hindered amide can generate Schiff base type quaternary ammonium salt, and the quaternary ammonium salt releases trifluoromethanesulfonic acid by dehydration through the enol intermediate state under the action of trace water in the system. In the process of synthesizing silicone oil by ring-opening polymerization, trifluoromethanesulfonic acid catalyzes the ring opening of cyclosiloxane to generate trifluoromethanesulfonic acid silicon alkoxide, and the hindered amide captures / releases trifluoromethanesulfonic acid and circulates continuously, causing the generated trifluoromethanesulfonic acid silicon alkoxide to continuously switch between silicon alkoxide and "dormant species", therefore, the generated trifluoromethanesulfonic acid silicon alkoxide will not have molecular chain "bite-back" to generate cyclosiloxane and macrocyclic siloxane by-products. Thus, the ring body content such as cyclosiloxane in the silicone oil product can be greatly reduced, and the ring body content is as low as 100ppm, and the product biological friendliness and environmental safety are greatly improved.

[0021] 2. When synthesizing epoxy silicone oil in the preparation method disclosed in the present invention, a Speier catalyst and a Karstedt's catalyst are combined to avoid catalyst poisoning caused by residual hindered amide in hydrogen-based silicone oil, and successfully realize the preparation of epoxy silicone oil by hydrosilylation reaction.

[0022] 3. The reaction conditions used in the preparation of epoxy silicone oil in the present invention are mild, the raw materials are cheap and easily available, the preparation process is simple, and it is suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of the hydrogen-based silicone oil prepared in Example 1 of the present invention.

[0024] Figure 2 This is the infrared spectrum of the hydrogen-based silicone oil prepared in Example 1 of the present invention.

[0025] Figure 3 This is the hydrogen nuclear magnetic resonance spectrum of the epoxy silicone oil prepared in Example 1 of the present invention.

[0026] Figure 4 This is the infrared spectrum of the epoxy silicone oil prepared in Example 1 of the present invention.

[0027] Figure 5 This is the infrared spectrum of the hydrogen-based silicone oil prepared in Example 4 of the present invention.

[0028] Figure 6 This is the infrared spectrum of the epoxy silicone oil prepared in Example 4 of the present invention. DETAILED DESCRIPTION

[0029] The preparation method of the low-ring-content epoxy silicone oil disclosed in the present invention is as follows: (1) generating a catalyst system; (2) ring-opening polymerization; (3) removing low-ring content; (4) hydrosilylation epoxidation. The specific steps are: (1) generating a catalyst system, wherein trifluoromethanesulfonic acid and hindered amide are dissolved in an aromatic solvent and reacted to obtain a trifluoromethanesulfonic acid / hindered amide catalyst system; (2) dimethylcyclosiloxane, methyl hydrogencyclosiloxane (optionally added) and a capping agent are mixed evenly, and then ring-opening polymerization is carried out under the catalysis of the trifluoromethanesulfonic acid / hindered amide catalyst system to prepare hydrogen-based silicone oil; (3) after step (2) is completed, the solvent and low molecular weight components are removed by vacuum distillation under reduced pressure until no liquid is distilled out, thereby obtaining hydrogen-based silicone oil; (4) the hydrogen-based silicone oil and allyl glycidyl ether are mixed evenly, a platinum catalyst is added, and the reaction is carried out by heat preservation to obtain an epoxy silicone oil with a low ring content.

[0030] In the above technical scheme, the catalyst system is generated in the preparation step (1) by reacting at room temperature for 1 to 5 hours; the hydrogen-based silicone oil prepared in the step (2) refers to the silicone oil containing hydrogen on its molecular chain; in the step (4) of hydrosilylation epoxidation, the platinum catalyst includes Speier catalyst and Karstedt's catalyst, and the weight ratio of hydrogen-based silicone oil, allyl glycidyl ether, Speier catalyst and Karstedt's catalyst is 10 to 1000 parts: 0.1 to 5 parts: 0.4×10 -5 ~1.2×10 -2 (Based on Pt mass) parts: 0.4×10 -5 ~1.2×10 -2 parts (by Pt mass); the reaction temperature is 70-105°C, and the reaction time is 1-12 hours.

[0031] The preparation method of the above-mentioned low-ring content epoxy silicone oil comprises the following steps:

[0032] (1) Generating a catalytic system: using trifluoromethanesulfonic acid and hindered amide as reactants, reacting in a solvent to obtain a catalytic system;

[0033] (2) Ring-opening polymerization: Cyclosiloxane monomers are mixed with capping agents and reacted under the catalysis of a catalyst system;

[0034] (3) Removal of low molecular weight components: The crude hydrogen-based silicone oil is distilled under reduced pressure to remove solvents and low molecular weight components;

[0035] (4) Hydrosilylation epoxidation: Epoxy silicone oil is prepared by hydrosilylation reaction of hydrogen silicone oil and allyl glycidyl ether as raw materials.

[0036] The specific steps are:

[0037] (1) Generation of catalytic system:

[0038] Trifluoromethanesulfonic acid and hindered amide are used as reactants, dissolved in an aromatic hydrocarbon solvent, and reacted at room temperature to obtain a catalytic system (Schiff base type quaternary ammonium salt). The reaction formula is as follows:

[0039]

[0040] Wherein, R2 and R3 are independently selected from methyl or phenyl; R4 is hydrogen or methyl.

[0041] (2) Ring-opening polymerization:

[0042] In a reactor, the cyclosiloxane monomer and the capping agent are mixed, and the above-prepared catalyst system is added to react. During the polymerization process, the quaternary ammonium salt releases trifluoromethanesulfonic acid through the enol intermediate state under the action of trace water in the system, and the hindered amide captures / releases trifluoromethanesulfonic acid and circulates. The synthetic reaction formula is as follows:

[0043]

[0044] Wherein, R1=hydrogen or methyl; m=3, 4 or an integer of 3 to 6; x=10 to 400, y=0 to 200; R2, R3 and R4 are the same as above. Preferably, y=0 and R1=methyl do not exist at the same time, that is, the hydrogen-based silicone oil molecular chain contains hydrogen.

[0045] (3) Removal of low molecular weight components: After the ring-opening polymerization is completed, the temperature is increased and the reduced pressure is distilled to remove the solvent and low molecular weight components to prepare hydrogen-based silicone oil;

[0046] (4) Hydrosilylation epoxidation: Epoxy silicone oil is prepared by hydrosilylation reaction of hydrogen silicone oil and allyl glycidyl ether under the action of platinum catalyst. The reaction formula is as follows:

[0047]

[0048] Among them, R ′ = methyl or glycidoxypropyl; x = 10 to 400, y = 0 to 200. Preferably, y = 0, R ′ =Methyl groups do not exist at the same time, that is, the epoxy silicone oil molecular chain contains epoxy groups.

[0049] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments. The raw materials used are all existing products, and the specific preparation operations (such as temperature control, stirring, etc.) and performance tests are conventional technologies. The Si-H content in the silicone oil sample is determined by chemical titration. The test principle is based on the fact that the Si-H bond in the sample can react with sodium hydroxide aqueous solution to generate hydrogen, measure the volume of the precipitated hydrogen, and calculate the hydrogen content in the sample based on the sampling amount, which is specifically the existing technology.

[0050] Embodiment 1

[0051] (1) Synthesis of trifluoromethanesulfonic acid / hindered amide composite catalyst

[0052] A 2L four-necked reaction flask was equipped with an electric heating jacket, a reflux condenser, a thermometer and a mechanical stirrer; after adding 150.0g of toluene and 0.8g of trifluoromethanesulfonic acid, stirring was started, and 1.1g of N,N´-dimethylacetamide was added dropwise. After the addition was completed, the reaction was stirred at room temperature for 1 hour to obtain a trifluoromethanesulfonic acid / hindered amide composite catalyst.

[0053] (2) Ring-opening polymerization

[0054] 800.0g of organosilicon cyclosiloxane mixed monomer DMC and 13.4g of hydrogen-based double head (hydrogen-containing double head, tetramethyldihydrogendisiloxane) were added to the above composite catalyst, and the mixture was kept warm at 60±5°C for 4h. After the reaction, 1.2g of sodium carbonate was added for neutralization reaction for 1h, and then filtered to obtain a colorless transparent filtrate.

[0055] (3) Take off the low

[0056] The filtrate was transferred to a 2L single-mouth reaction bottle and degassed for 2 hours at 100±5°C and 40mmHg vacuum under magnetic stirring. When no more liquid was distilled out, degassed and 773.5g of colorless transparent hydrogen-based silicone oil product was obtained with a yield of 95.1%. The hydrogen content of the prepared hydrogen-based silicone oil was measured to be 0.023%. Its hydrogen nuclear magnetic resonance spectrum can be found in Figure 1 , infrared absorption curve is attached Figure 2 , FT-IR(n): 2980, 2900 (CH3, CH2), 2120 (Si-H), 1265 (Si-CH3), 1030-1018 (Si-O-Si) cm -1 .

[0057] (4) Preparation of epoxy silicone oil by hydrosilylation epoxidation

[0058] A 2L four-necked reaction flask was equipped with an electric heating jacket, reflux condenser, thermometer and mechanical stirring. Under nitrogen protection, 600.0 g of hydrogen silicone oil, 0.9 g of Speier catalyst, and 0.9 g of Karstedt's catalyst were added in sequence, and then 16.1 g of allyl glycidyl ether was added dropwise at 75±5°C. After 1 hour of addition, the mixture was kept warm for 3 hours. After stopping the reaction, the mixture was cooled naturally to obtain 603.8 g of the product, the chemical structure of which was:

[0059]

[0060] The product H NMR spectrum is shown in Figure 3 , infrared absorption curve is attached Figure 4, FT-IR(n): 2985, 2900 (CH3, CH2), 1265 (Si-CH3), 1030-1018 (Si-O-Si, epoxy group) cm -1 The number average molecular weight (Mn) of the product was measured to be 8200, and the ring body content (four types of D3, D4, D5, and D6) in the epoxy silicone oil product was measured by GC to be 107 ppm in total.

[0061] Embodiment 2

[0062] (1) Synthesis of trifluoromethanesulfonic acid / hindered amide composite catalyst

[0063] A 2L four-necked reaction flask was equipped with an electric heating jacket, a reflux condenser, a thermometer and a mechanical stirrer. After adding 150.5g of toluene and 0.9g of trifluoromethanesulfonic acid, stirring was started, and 1.1g of N,N'-dimethylacetamide was added dropwise. After the addition was completed, the mixture was stirred at room temperature for 1 hour to obtain a trifluoromethanesulfonic acid / hindered amide composite catalyst.

[0064] (2) Ring-opening polymerization

[0065] 800.0g of organosilicon cyclosiloxane mixed monomer DMC and 5.8g of hydrogen-based double-capped were added to the composite catalyst, and the mixture was kept warm at 60±5°C for 4h. After the reaction, 1.2g of sodium carbonate was added for neutralization and reaction for 1h. The mixture was filtered to obtain a colorless transparent filtrate.

[0066] (3) Take off the low

[0067] The filtrate was transferred to a 2L single-mouth reaction bottle and degassed under magnetic stirring at 100±5°C and 40mmHg vacuum for 2h. No more liquid was distilled out and the degassed was stopped to obtain 757.5g of colorless transparent product with a yield of 94.0%. The hydrogen content of the tested product was 0.009%.

[0068] (4) Preparation of epoxy silicone oil by hydrosilylation epoxidation

[0069] A 2L four-necked reaction flask was equipped with an electric heating jacket, reflux condenser, thermometer and mechanical stirring. Under nitrogen protection, 600.0 g of hydrogen silicone oil, 0.9 g of Speier catalyst, and 0.9 g of Karstedt's catalyst were added in sequence, and 8.1 g of allyl glycidyl ether was added dropwise at 75±5°C for 1 hour. After the addition, the mixture was kept warm for 3 hours. After stopping the reaction, the mixture was cooled to obtain 595.7 g of the product, the chemical structure of which was:

[0070]

[0071] The number average molecular weight (Mn) of the product was measured to be 18500, and the ring body content (four types, D3, D4, D5, and D6) in the epoxy silicone oil product was measured by GC to be 123 ppm in total.

[0072] Embodiment 3

[0073] (1) Synthesis of trifluoromethanesulfonic acid / hindered amide composite catalyst

[0074] A 2L four-necked reaction flask was equipped with an electric heating jacket, a reflux condenser, a thermometer and a mechanical stirrer. After adding 150.0g of toluene and 0.9g of trifluoromethanesulfonic acid, stirring was started, and 1.1g of N,N'-dimethylacetamide was added dropwise. After the addition was completed, the mixture was stirred at room temperature for 1 hour to obtain a trifluoromethanesulfonic acid / hindered amide composite catalyst.

[0075] (2) Ring-opening polymerization

[0076] 740.0g of organosilicon cyclosiloxane mixed monomer DMC, 60.5g of tetramethylcyclotetrasiloxane (D4H) and 10.2g of hexamethyldisiloxane were added to the above composite catalyst for capping, and the mixture was kept warm at 65±5°C for 4h. After the reaction, 1.2g of sodium carbonate was added for neutralization and reaction for 1h. The mixture was filtered to obtain a colorless transparent filtrate.

[0077] (3) Take off the low

[0078] The filtrate was transferred to a 2L single-mouth reaction bottle and degassed under magnetic stirring at 100±5°C and 40 mmHg vacuum for 2 h. No more liquid was distilled out and the degassed was stopped to obtain 774.2 g of colorless transparent product with a yield of 95.5%. The hydrogen content of the tested product was 0.121%.

[0079] (4) Preparation of epoxy silicone oil by hydrosilylation epoxidation

[0080] A 2L four-necked reaction flask was equipped with an electric heating jacket, reflux condenser, thermometer and mechanical stirring. Under nitrogen protection, 600.0 g of hydrogen silicone oil, 0.9 g of Speier catalyst, and 0.9 g of Karstedt's catalyst were added in sequence, and 56.2 g of allyl glycidyl ether was added dropwise at 75±5°C for 1 hour. After the addition, the mixture was kept warm for 3 hours. After stopping the reaction, the mixture was cooled to obtain 610.2 g of the product, the chemical structure of which was:

[0081]

[0082] The number average molecular weight (Mn) of the product was measured to be 12880, and the ring body content (four types, D3, D4, D5, and D6) in the epoxy silicone oil product was measured by GC to be 131 ppm in total.

[0083] Embodiment 4

[0084] (1) Synthesis of trifluoromethanesulfonic acid / hindered amide composite catalyst

[0085] A 2L four-necked reaction flask was equipped with an electric heating jacket, a reflux condenser, a thermometer and a mechanical stirrer. After adding 150.0g toluene and 0.9g trifluoromethanesulfonic acid, stirring was started, and 1.1g N,N'-dimethylacetamide was added dropwise. After the addition, the mixture was stirred at room temperature for 1 hour to obtain a trifluoromethanesulfonic acid / hindered amide composite catalyst.

[0086] (2) Ring-opening polymerization

[0087] 790.0g of organosilicon cyclosiloxane mixed monomer DMC, 12.2g of tetramethylcyclotetrasiloxane (D4H) and 10.2g of hydrogen-based double-capped head were added to the above composite catalyst, and the mixture was kept warm at 60±5°C for 4h. After the reaction, 1.2g of sodium carbonate was added for neutralization and reaction for 1h, and then filtered to obtain a colorless transparent filtrate.

[0088] (3) Take off the low

[0089] The above filtrate was transferred to a 2L single-mouth reaction bottle and degassed at 100±5°C and 40mmHg vacuum for 2h under magnetic stirring. No more liquid was distilled out and the degassed was stopped to obtain 777.8g of colorless transparent product with a yield of 95.9%. The hydrogen content of the product was 0.051%. Its infrared absorption curve is attached. Figure 5 , FT-IR(n): 2981, 2900 (CH3, CH2), 2120 (Si-H), 1265 (Si-CH3), 1031-1015 (Si-O-Si) cm -1 .

[0090] (4) Preparation of epoxy silicone oil by hydrosilylation epoxidation

[0091] A 2L four-necked reaction flask was equipped with an electric heating jacket, reflux condenser, thermometer and mechanical stirring. Under nitrogen protection, 600.0 g of hydrogen silicone oil, 0.9 g of Speier catalyst, and 0.9 g of Karstedt's catalyst were added in sequence, and 10.2 g of allyl glycidyl ether was added dropwise at 75±5°C. After 1 hour of addition, the mixture was kept warm for 3 hours. After stopping the reaction, the mixture was cooled to obtain 591.7 g of the product, the chemical structure of which was:

[0092]

[0093] The infrared absorption curve of the product is attached. Figure 6 , FT-IR(n): 2981, 2900 (CH3, CH2), 1265 (Si-CH3), 1029-1016 (Si-O-Si, epoxy group) cm -1 The number average molecular weight (Mn) of the product was measured to be 10500, and the ring body content (four types of D3, D4, D5, and D6) in the epoxy silicone oil product was measured by GC to be 112 ppm in total.

[0094] Comparative Example 1

[0095] (1) Ring-opening polymerization

[0096] A 2L four-necked reaction flask was equipped with an electric heating jacket, reflux condenser, thermometer and mechanical stirring. After adding 150.0g toluene and 0.8g trifluoromethanesulfonic acid, stirring was started, and 800.0g organosilicon cyclosiloxane mixed monomer DMC and 13.4g hydrogen-based double-capped were added in sequence, and the mixture was kept warm at 60±5℃ for 4h. After the reaction, 1.2g sodium carbonate was added for neutralization reaction for 1h, and then filtered to obtain a colorless transparent filtrate.

[0097] (2) Take off the low

[0098] The filtrate was transferred to a 2L single-mouth reaction bottle and degassed under magnetic stirring at 100±5°C and 40 mmHg vacuum for 2 h. When no more liquid was distilled out, the degassed was stopped to obtain 650.7 g of a colorless transparent product. The hydrogen content of the product was tested to be 0.021%.

[0099] (3) Epoxy silicone oil was prepared by hydrosilylation epoxidation with reference to Example 1 to obtain 598.6 g of product. The number average molecular weight (Mn) of the product was measured to be 8080. The cyclic body content (four types, D3, D4, D5, and D6) in the epoxy silicone oil product was measured by GC to be 2012 ppm in total.

[0100] Comparative Example 2

[0101] (1) Ring-opening polymerization

[0102] A 2L four-necked reaction flask was equipped with an electric heating jacket, reflux condenser, thermometer and mechanical stirring. After adding 150.0g toluene and 1.8g concentrated sulfuric acid with a mass concentration of 95%, stirring was started, and 800.0g organosilicon cyclosiloxane mixed monomer DMC and 13.4g hydrogen-based double-capped were added in sequence, and the mixture was kept warm at 60±5℃ for 4h. After the reaction, 2.3g sodium carbonate was added for neutralization reaction for 1h, and filtered to obtain a colorless transparent filtrate.

[0103] (2) Take off the low

[0104] The filtrate was transferred to a 2L single-mouth reaction bottle and degassed under magnetic stirring at 100±5°C and 40 mmHg vacuum for 2 h. When no more liquid was distilled out, the degassed was stopped to obtain 611.3 g of a colorless transparent product. The hydrogen content of the product was tested to be 0.022%.

[0105] (3) Referring to Example 1, hydrosilylation epoxidation was carried out to prepare epoxy silicone oil. 604.5 g of product was obtained, and the number average molecular weight (Mn) of the product was measured to be 8250. The cyclic body content (four types of D3, D4, D5, and D6) in the epoxy silicone oil product was measured by GC to be 2890 ppm in total. It can be seen that the cyclic body content of the silicone oil prepared by the conventional concentrated sulfuric acid-catalyzed ring-opening polymerization of cyclosiloxane is very high.

[0106] Comparative Example 3

[0107] (1) A 2L four-necked reaction flask was equipped with an electric heating jacket, a reflux condenser, a thermometer and a mechanical stirrer. After adding 150.0g of toluene and 0.9g of trifluoromethanesulfonic acid, stirring was started, and 1.1g of triethylamine was added dropwise. After the addition was complete, the mixture was stirred at room temperature for 1 hour to obtain a composite catalyst.

[0108] (2) Ring-opening polymerization

[0109] 740.0 g of organosilicon cyclosiloxane mixed monomer DMC, 60.5 g of tetramethylcyclotetrasiloxane (D4H) and 10.2 g of hexamethyldisiloxane were added to the composite catalyst in sequence, and the mixture was kept warm at 65±5°C for 4 h. After the reaction, 1.2 g of sodium carbonate was added for neutralization and reaction for 1 h. The mixture was filtered to obtain a colorless transparent filtrate.

[0110] (3) Take off the low

[0111] The filtrate was transferred to a 2L single-mouth reaction bottle and degassed under magnetic stirring at 100±5°C and 40 mmHg vacuum for 2 h. When no more liquid was distilled out, the degassed was stopped to obtain 616.9 g of a colorless transparent product. The hydrogen content of the product was tested to be 0.120%.

[0112] (4) Preparation of epoxy silicone oil by hydrosilylation epoxidation

[0113] The 2L four-mouth reaction flask was equipped with an electric heating jacket, a reflux condenser, a thermometer and a mechanical stirrer. Under nitrogen protection, 600.0 g of hydrogen silicone oil, 0.9 g of speier catalyst, and 0.9 g of Karstedt's catalyst were added in sequence, and 16.1 g of allyl glycidyl ether was added dropwise at 75±5°C for 1 hour. After the addition, the reaction was kept warm for 3 hours. After stopping the reaction, the product was cooled to obtain 601.2 g of product, and the number average molecular weight (Mn) of the product was measured to be 8100. The cyclic body content (D3, D4, D5, and D6) in the epoxy silicone oil product was measured by GC to be 3560 ppm in total. When trifluoromethanesulfonic acid and triethylamine were used as the catalyst system to catalyze the ring-opening polymerization of cyclosiloxane, the yield of silicone oil was low, and the prepared silicone oil cyclic body content was very high.

[0114] Embodiment 5

[0115] Referring to Example 1, wherein N,N'-dimethylacetamide is replaced by N,N'-dimethylformamide or N,N'-methylphenylformamide, and the rest is the same, the obtained silicone oil ring body contents are 116 ppm and 122 ppm respectively.

[0116] Embodiment 6

[0117] Referring to Example 1, the stirring reaction time at room temperature in step (1) is adjusted to 1.5 hours or 2 hours, or the ring-opening polymerization reaction is adjusted to 70±5°C / 3 hours, and the content of the obtained silicone oil ring body is less than 112 ppm.

[0118] Embodiment 7

[0119] Referring to Example 1, the dehumidification conditions were adjusted to 110±5°C and 35 mmHg, and the obtained silicone oil ring body content was 102 ppm.

[0120] Embodiment 8

[0121] Referring to Example 1, the reaction temperature of the hydrosilylation reaction was 80±5° C., the heat preservation reaction time was 2 hours, and the content of the obtained silicone oil ring body was 106 ppm.

[0122] At present, the silicone oil on the market contains a mixture of dimethylsiloxane ring bodies, mainly hexamethylcyclotrisiloxane (D3), octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), and dodecamethylcyclohexasiloxane (D6). The residual organosilicon ring bodies will seriously limit the application of organosilicon products, especially in the food, cosmetics, and medical industries. The total ring body content of the silicone oil currently on the market exceeds 800ppm, and most of them exceed 1000ppm. The researchers adopted methods such as changing the silicone oil production process and its production system, adding piperidine compound adjuvants, nitrogen drums to help remove the ring bodies, and high temperature (140-180°C) vacuuming. In the obtained product, the content of the ring body mixture is still high and it is difficult to be lower than 400ppm. The present invention uses cyclosiloxane monomers and disiloxane double heads as raw materials, trifluoromethanesulfonic acid and hindered amine as the catalyst system, and ring-opening polymerization to generate hydrogen-based silicone oil; hydrogen-based silicone oil and allyl glycidyl ether are reacted by hydrosilylation to obtain epoxy silicone oil. In the ring-opening polymerization process of cyclosiloxane, trifluoromethanesulfonic acid and hindered amide are used as the catalytic system, so that the generated silicon alkoxide is constantly switched between trifluoromethanesulfonic acid silicon alkoxide and "dormant species", so as to avoid the generated trifluoromethanesulfonic acid silicon alkoxide from "biting back" the molecular chain to generate cyclosiloxane and macrocyclic siloxane byproducts. The present invention greatly reduces the content of cyclosiloxane and other ring bodies in the silicone oil product, unexpectedly as low as about 100ppm, and the biofriendliness and environmental safety of the silicone oil product are greatly improved. Further, when the hydrogen-based silicone oil synthesized thereby and allyl glycidol are synthesized by hydrosilylation reaction of epoxy silicone oil, in order to avoid catalyst poisoning caused by residual hindered amide, the present invention adopts the method of Speier catalyst and Karstedt's catalyst composite, and successfully realizes the preparation of epoxy silicone oil by hydrosilylation reaction. The reaction conditions used in the preparation of epoxy silicone oil by the present invention are mild, the raw materials are cheap and easy to obtain, the preparation process is simple, and it is suitable for industrial production.

Claims

1. A method for preparing low-ring content epoxy silicone oil, characterized in that: The following steps are involved: Trifluoromethanesulfonic acid and hindered amide are reacted to obtain a trifluoromethanesulfonic acid / hindered amide catalyst system; in the presence of the trifluoromethanesulfonic acid / hindered amide catalyst system, siloxane and a capping agent are used as raw materials to carry out a ring-opening polymerization reaction to prepare hydrogen-based silicone oil; then hydrogen-based silicone oil and epoxy compound are used as raw materials to carry out a hydrosilylation reaction to prepare low-ring content epoxy silicone oil; the siloxane is dimethylcyclosiloxane, or dimethylcyclosiloxane and methylhydrogencyclosiloxane; the hindered amide includes one or more of N,N'-dimethylformamide, N,N'-dimethylacetamide, and N,N'-methylphenylformamide; the weight ratio of trifluoromethanesulfonic acid to hindered amide is 1: (0.1-5); and the reaction time is 0.1-12 hours.

2. The method for preparing low-ring content epoxy silicone oil according to claim 1, characterized in that: The weight ratio of dimethylcyclosiloxane, methylhydrogencyclosiloxane and capping agent is 10000: (0-5000): (0.1-500); the temperature of the ring-opening polymerization reaction is 50-100°C, and the time is 1-24 hours.

3. The method for preparing low-cyclic epoxy silicone oil according to claim 1, characterized in that: After the ring-opening polymerization reaction is completed, desulfurization is carried out to obtain hydrogen-based silicone oil.

4. The method for preparing low-ring content epoxy silicone oil according to claim 1, characterized in that: During the hydrosilylation reaction, the catalyst is a platinum catalyst, and the epoxy compound is allyl glycidyl ether; the temperature of the hydrosilylation reaction is 70 to 105° C., and the time is 1 to 12 hours.

5. The low-ring content epoxy silicone oil prepared by the preparation method according to claim 1.

6. Use of the low-ring content epoxy silicone oil according to claim 5 in the preparation of organosilicon materials.

7. A method for preparing a low-ring content hydrogen-based silicone oil, characterized in that: The following steps are involved: Trifluoromethanesulfonic acid and hindered amide are reacted to obtain a trifluoromethanesulfonic acid / hindered amide catalyst system; in the presence of the trifluoromethanesulfonic acid / hindered amide catalyst system, siloxane and a capping agent are used as raw materials to carry out a ring-opening polymerization reaction to prepare a low-ring content hydrogen-based silicone oil; the siloxane is dimethylcyclosiloxane, or dimethylcyclosiloxane and methylhydrogencyclosiloxane; the hindered amide includes one or more of N,N'-dimethylformamide, N,N'-dimethylacetamide, and N,N'-methylphenylformamide; the weight ratio of trifluoromethanesulfonic acid to hindered amide is 1: (0.1-5); and the reaction time is 0.1-12 hours.

8. The low-ring-content hydrogen-based silicone oil prepared by the preparation method according to claim 7.

9. Use of the low-cyclic hydrogen-based silicone oil according to claim 8 in the preparation of organosilicon materials.

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