Distillation and purification method for preparing silane coupling agent

Abstract

The invention discloses a distillation purification method for preparing a silane coupling agent, and belongs to the technical field of preparation of silane coupling agents. The distillation and purification method for preparing the silane coupling agent comprises the following steps: step 1, mixing a silane coupling agent crude product, tetrahydrofuran, an organic antioxidant and an auxiliary agent, heating, mixing and stirring to obtain a mixture; 2, adding the mixture into a distillation tower, heating and distilling, controlling the heating temperature and the distillation rate, and ensuring stable and continuous evaporation and condensation of the silane coupling agent; and 3, collecting the condensed liquid into a collector, separating the liquid, filtering, and drying to obtain the silane coupling agent. According to the method, the product purity and yield of the silane coupling agent can be effectively improved.

Description

Technical Field

[0001] The invention belongs to the technical field of silane coupling agent preparation, and particularly relates to a distillation purification method for preparing a silane coupling agent. Background Art

[0002] Silane coupling agent is an organosilicon compound with a special structure. Its molecules contain organic and inorganic functional groups, which make silane coupling agent have the function of connecting the interface between organic and inorganic materials. Through the action of silane coupling agent, the interface of two materials with very different properties can be coupled, thereby improving the performance of composite materials and increasing the bonding strength. This unique property makes silane coupling agent widely used in rubber, plastic, filled composite materials, epoxy packaging materials, elastomers, coatings, adhesives and sealants. In the preparation process of silane coupling agent, distillation purification is a key link. After the reaction is completed, the crude silane coupling agent is obtained, which contains impurities such as unreacted raw materials, catalyst residues and by-products. In order to obtain a high-purity silane coupling agent product, the crude product needs to be further purified. Distillation purification, as a commonly used chemical separation technology, has the advantages of high separation efficiency and simple operation, and therefore becomes an important means of purifying silane coupling agent.

[0003] Patent CN 103626795A discloses a method for preparing a silane coupling agent, comprising the following steps: (1) mixing aminosilicon with phthalic acid, adding an organic solvent, and mixing and stirring; (2) adding a strong acid to the above-mentioned mixed solution, reacting, and obtaining a silane coupling agent. The silane coupling agent synthesized by the method of the invention has a heteroaromatic ring introduced into the siloxane main chain, which can improve its comprehensive performance without reducing its heat resistance. However, the yield and purity of the silane coupling agent prepared by this method still have room for improvement. Summary of the invention

[0004] The purpose of the present invention is to provide a distillation purification method for preparing a silane coupling agent, which is used to solve the technical problems of poor yield and purity of the silane coupling agent in the prior art.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] The present invention provides a distillation purification method for preparing a silane coupling agent, comprising the following steps:

[0007] Step 1: Mix the crude silane coupling agent, tetrahydrofuran, an organic antioxidant and an auxiliary agent, heat, mix and stir to obtain a mixture;

[0008] Step 2: Add the mixture to a distillation tower, heat and distill, control the heating temperature and distillation rate to ensure smooth and continuous distillation and condensation of the silane coupling agent;

[0009] Step 3: Collect the condensed liquid into a collector, separate the liquid, filter, and dry to obtain a silane coupling agent.

[0010] Preferably, in step 1, the usage ratio of crude silane coupling agent, tetrahydrofuran, organic antioxidant and auxiliary agent is (10-15) g: (5-8) mL: (0.1-0.5) g: (0.05-0.2) g, the heating temperature is 40-50° C., and the heating time is 4-6 h.

[0011] Preferably, the method for preparing the organic antioxidant comprises the following steps:

[0012] Q1: Add indole to a container, then add p-toluenesulfonyl azide, heat to condense and reflux, add anhydrous methanol after reflux, stir, filter, and obtain a pink solid, add the pink solid, dichloromethane, benzaldehyde and boron trifluoride ether to the container in sequence under argon atmosphere, stir to react, add anhydrous methanol, ultrasonically treat, a yellow solid precipitates, filter, and dry to obtain intermediate 1;

[0013] Q2: Add benzoyl chloride, phenylhydrazine and triethylamine to a container containing dichloromethane in sequence, react at room temperature, add hydrochloric acid after the reaction is completed, extract, collect the organic phase, concentrate under reduced pressure, and purify to obtain compound 1, add compound 1, acetonitrile, triphenylphosphine and carbon tetrachloride to a container in sequence, react at room temperature, distill under reduced pressure, and purify to obtain intermediate 2;

[0014] Q3: Add intermediate product 1 to a container, then add mesitylene, stir, add intermediate product 2, heat and stir to react, after the reaction is completed, purify by chromatography to obtain an organic antioxidant.

[0015] In the above process, the synthesis reaction formula of the organic antioxidant is as follows:

[0016]

[0017] The results of mass spectrometry analysis of intermediate product 1 were: m / z: 361.11 (100.0%), 362.12 (24.1%), 363.11 (4.6%), 363.12 (3.4%), 362.11 (1.2%), 364.11 (1.1%); the results of mass spectrometry analysis of intermediate product 2 were: m / z: 230.06 (100.0%), 232.06 (32.1 %), 231.06 (14.8%), 233.06 (4.8%); the results of mass spectrometry analysis of organic antioxidants were: m / z: 569.21 (100.0%), 570.22 (39.4%), 571.22 (8.3%), 571.21 (5.0%), 570.21 (1.9%), 572.21 (1.8%), 572.22 (1.2%).

[0018] Preferably, in Q1, the dosage ratio of indole, p-toluenesulfonyl azide and anhydrous methanol is (9.53-19.06) g: (10.85-21.7) mL: (1-2) mL, the heating condensation reflux temperature is 60-70°C, the reflux time is 10-12 h, the stirring time is 30-45 min, the dosage ratio of pink solid, dichloromethane, benzaldehyde, boron trifluoride ether and anhydrous methanol is (1.2-2.4) g: (8-16) mL: (1.3-2.6) mL: (2.6-5.2) mL: (2-2.7) mL, the stirring reaction time is 1-2 h, and the ultrasonic treatment time is 30-45 min.

[0019] Preferably, in Q2, the amount ratio of benzoyl chloride, phenylhydrazine, triethylamine and dichloromethane is (1.3-2.6) g: (1-2) g: (2.06-4.12) g: (5-8) mL, the reaction time at room temperature is 10-12 h, the concentration of hydrochloric acid is 1 mol / L, and dichloromethane is used for extraction. The amount ratio of compound 1, acetonitrile, triphenylphosphine and carbon tetrachloride is (1-1.5) g: (3.12-4.56) mL: (2.34-4.67) g: (4-7) mL, and the reaction time at room temperature is 12-14 h;

[0020] Preferably, in Q3, the dosage ratio of intermediate product 1, mesitylene and intermediate product 2 is (0.5-0.8) g: (0.5-1) mL: (0.67-0.83) g, the heating temperature is 40-50°C, the reaction time is 6-8h, and a mixed solution of petroleum ether and ethyl acetate in a volume ratio of 4:1 is used as the eluent for chromatography purification.

[0021] Preferably, the preparation method of the auxiliary agent comprises the following steps:

[0022] S1: adding melamine into a crucible, sealing the crucible, and then placing the crucible in a muffle furnace for heating. After the heating is completed, cooling and grinding are performed to obtain a solid catalyst;

[0023] S2: Add methyl ricinoleate and isopropanol into a container, stir and mix evenly, add sodium bisulfite into distilled water, stir and add into the container, then add solid catalyst, heat and stir, stir thoroughly, cool, filter, extract, rotary evaporate, desalinate, recrystallize, and dry to obtain an auxiliary agent.

[0024] In the above process, melamine undergoes polymerization reaction under high temperature environment to obtain a solid catalyst, and then methyl ricinoleate is used as a starting material to undergo addition sulfonation reaction with a carbon-carbon double bond through sodium bisulfite to obtain an auxiliary agent, wherein the synthetic reaction formula of the auxiliary agent is as follows:

[0025]

[0026] The results of mass spectrometry analysis were: m / z: 416.22 (100.0%), 417.22 (21.4%), 418.22 (4.7%), 418.23 (3.4%), 419.22 (1.0%).

[0027] Preferably, in S1, the heating process is: heating to 450°C at a heating rate of 2°C / min and maintaining for 4 hours.

[0028] Preferably, in S2, the dosage ratio of methyl ricinoleate, isopropanol, sodium bisulfite, distilled water and solid catalyst is (11-20) g: (50-80) mL: (14.5-20) g: (50-75) mL: (2-2.5) g, the heating temperature is 40-50°C, the stirring time is 20-24h, extraction is carried out with petroleum ether, and anhydrous ethanol is added for desalination.

[0029] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0030] 1. The present invention first uses indole, p-toluenesulfonyl azide, benzaldehyde, benzoyl chloride, phenylhydrazine and carbon tetrachloride as raw materials to prepare an organic antioxidant, and then uses melamine 、 The auxiliary agent is prepared by taking ricinoleic acid methyl ester and sodium bisulfite as raw materials. In the distillation and purification process of the silane coupling agent, adding the organic antioxidant and the auxiliary agent can effectively improve the yield and purity thereof.

[0031] 2. The present invention uses indole, p-toluenesulfonyl azide, benzaldehyde, benzoyl chloride, phenylhydrazine and carbon tetrachloride as raw materials to prepare an organic antioxidant. In the preparation process of the silane coupling agent, the free radicals generated will trigger a chain reaction, resulting in the destruction of the molecular structure or the generation of by-products. At the same time, the silane coupling agent is also prone to oxidation reaction with oxygen in the air, reducing the purity and yield of the product. The presence of the organic antioxidant can effectively remove the free radicals, reduce the probability of chain reaction, and protect the integrity of the silane coupling agent molecules. At the same time, it can also inhibit the oxidation reaction and reduce the contact opportunity between the silane coupling agent and oxygen. The organic antioxidant also has the function of stabilizing the molecular structure, preventing the silane coupling agent from decomposing or isomerizing during the purification process, maintaining its performance and quality, and improving the purity and yield of the product. At the same time, the thermal stability of the organic antioxidant prevents it from decomposing and generating impurities during the distillation purification process, thereby improving the quality of the silane coupling agent.

[0032] 3. The present invention uses melamine 、 The auxiliary agent is prepared by taking ricinoleic acid methyl ester and sodium bisulfite as raw materials. The auxiliary agent is used in the process of distillation purification to effectively improve the purity and yield of the silane coupling agent. The presence of the auxiliary agent can effectively reduce the surface tension, improve the fluidity, reduce the interaction between droplets, and improve the distillation efficiency. The auxiliary agent can also react with the free radicals or active intermediates generated in the distillation to inhibit the occurrence of side reactions, reduce the generation of by-products, and improve the purity of the silane coupling agent. The auxiliary agent can also form a thin film between the molecules of the silane coupling agent, promote the orderly arrangement of the molecules, reduce the interaction and agglomeration between the molecules, and further improve the distillation efficiency. At the same time, the presence of the auxiliary agent can also reduce the residue of the silane coupling agent in the distillation tower and improve its yield. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] Example 1: This example discloses a method for preparing an organic antioxidant, comprising the following steps:

[0035] Q1: 14.3 g of indole was added to a container, followed by 16.28 mL of p-toluenesulfonyl azide, and the mixture was heated at 70°C for condensation and reflux for 12 h. After the reflux was completed, 1.5 mL of anhydrous methanol was added, stirred for 45 min, and filtered to obtain a pink solid. 1.8 g of the pink solid, 12 mL of dichloromethane, 1.9 mL of benzaldehyde, and 3.9 mL of boron trifluoride ether were added to the container in sequence under an argon atmosphere, stirred for 2 h, 2.35 mL of anhydrous methanol was added, and ultrasonic treatment was performed for 30 min. A yellow solid was precipitated, which was filtered and dried to obtain an intermediate product 1.

[0036] Q2: 1.95 g of benzoyl chloride, 1.5 g of phenylhydrazine and 3.09 g of triethylamine were added to a container containing 6.5 mL of dichloromethane in sequence, and reacted at room temperature for 12 h. After the reaction was completed, 2 mL of 1 mol / L hydrochloric acid was added, and extracted with dichloromethane. The organic phase was collected, concentrated under reduced pressure, and purified to obtain compound 1. 1.25 g of compound 1, 3.83 mL of acetonitrile, 3.51 g of triphenylphosphine and 5.5 mL of carbon tetrachloride were added to a container in sequence, reacted at room temperature for 12 h, and then distilled under reduced pressure and purified to obtain intermediate 2;

[0037] Q3: Add 0.65 g of intermediate product 1 to a container, then add 0.75 mL of mesitylene, stir, then add 0.75 g of intermediate product 2, heat and stir at 50°C for 6 hours. After the reaction, use a mixed solution of petroleum ether and ethyl acetate in a volume ratio of 4:1 as eluent for chromatography purification to obtain an organic antioxidant.

[0038] This embodiment discloses a method for preparing an auxiliary agent, comprising the following steps:

[0039] S1: adding melamine into a crucible, sealing the crucible, and then placing the crucible in a muffle furnace for heating treatment, the process is: heating to 450°C at a heating rate of 2°C / min, maintaining for 4 hours, cooling after heating, grinding, and obtaining a solid catalyst;

[0040] S2: Add 15.5g of methyl ricinoleate and 65mL of isopropanol into a container, stir and mix evenly, then add 17g of sodium bisulfite into 62.5mL of distilled water, stir and add into the container, then add 2.25g of solid catalyst, heat and stir at 40℃ for 24h, stir well, cool after stirring, filter, extract with petroleum ether, rotary evaporate, add anhydrous ethanol for desalination, recrystallize, dry to obtain an auxiliary agent.

[0041] This embodiment discloses a distillation purification method for preparing a silane coupling agent, comprising the following steps:

[0042] Step 1: 12.5 g of crude silane coupling agent, 6.5 mL of tetrahydrofuran, 0.3 g of organic antioxidant and 0.125 g of auxiliary agent were mixed, heated at 50° C. and stirred for 4 h to obtain a mixture;

[0043] Step 2: Add the mixture to a distillation tower, heat and distill, control the heating temperature and distillation rate to ensure smooth and continuous distillation and condensation of the silane coupling agent;

[0044] Step 3: Collect the condensed liquid into a collector, separate the liquid, filter, and dry to obtain a silane coupling agent.

[0045] Example 2: This example discloses a method for preparing an organic antioxidant, comprising the following steps:

[0046] Q1: 9.53 g of indole was added to a container, followed by 10.85 mL of p-toluenesulfonyl azide, and the mixture was heated at 70°C for condensation and reflux for 12 h. After the reflux was completed, 1 mL of anhydrous methanol was added, stirred for 45 min, and filtered to obtain a pink solid. 1.2 g of the pink solid, 8 mL of dichloromethane, 1.3 mL of benzaldehyde, and 2.6 mL of boron trifluoride ether were added to the container in sequence under an argon atmosphere, stirred for 2 h, 2.7 mL of anhydrous methanol was added, and ultrasonic treatment was performed for 30 min. A yellow solid was precipitated, which was filtered and dried to obtain an intermediate product 1.

[0047] Q2: 1.3 g of benzoyl chloride, 1 g of phenylhydrazine and 2.06 g of triethylamine were added to a container containing 5 mL of dichloromethane in sequence, and the mixture was reacted at room temperature for 12 h. After the reaction was completed, 2 mL of 1 mol / L hydrochloric acid was added, and the mixture was extracted with dichloromethane. The organic phase was collected, concentrated under reduced pressure, and purified to obtain compound 1. 1 g of compound 1, 3.12 mL of acetonitrile, 2.34 g of triphenylphosphine and 4 mL of carbon tetrachloride were added to a container in sequence, and the mixture was reacted at room temperature for 12 h, and then distilled under reduced pressure and purified to obtain intermediate 2.

[0048] Q3: Add 0.5 g of intermediate product 1 to a container, then add 0.5 mL of mesitylene, stir, then add 0.67 g of intermediate product 2, heat and stir at 50°C for 6 h. After the reaction, use a mixed solution of petroleum ether and ethyl acetate in a volume ratio of 4:1 as eluent for chromatography purification to obtain an organic antioxidant.

[0049] This embodiment discloses a method for preparing an auxiliary agent, comprising the following steps:

[0050] S1: adding melamine into a crucible, sealing the crucible, and then placing the crucible in a muffle furnace for heating treatment, the process is: heating to 450°C at a heating rate of 2°C / min, maintaining for 4 hours, cooling after heating, grinding, and obtaining a solid catalyst;

[0051] S2: Add 11g of methyl ricinoleate and 50mL of isopropanol into a container, stir and mix evenly, then add 14.5g of sodium bisulfite into 50mL of distilled water, stir evenly and add into the container, then add 2g of solid catalyst, heat to 40℃ and stir for 24h, stir well, cool after stirring, filter, extract with petroleum ether, rotary evaporate, add anhydrous ethanol for desalination, recrystallize and dry to obtain an auxiliary agent.

[0052] This embodiment discloses a distillation purification method for preparing a silane coupling agent, comprising the following steps:

[0053] Step 1: 10 g of crude silane coupling agent, 5 mL of tetrahydrofuran, 0.5 g of organic antioxidant and 0.05 g of auxiliary agent were mixed, heated at 50° C. and stirred for 4 h to obtain a mixture;

[0054] Step 2: Add the mixture to a distillation tower, heat and distill, control the heating temperature and distillation rate to ensure smooth and continuous distillation and condensation of the silane coupling agent;

[0055] Step 3: Collect the condensed liquid into a collector, separate the liquid, filter, and dry to obtain a silane coupling agent.

[0056] Example 3: This example discloses a method for preparing an organic antioxidant, comprising the following steps:

[0057] Q1: 19.06 g of indole was added to a container, followed by 21.7 mL of p-toluenesulfonyl azide, and the mixture was heated at 70°C for condensation and reflux for 12 h. After the reflux was completed, 2 mL of anhydrous methanol was added, stirred for 45 min, and filtered to obtain a pink solid. 2.4 g of the pink solid, 16 mL of dichloromethane, 2.6 mL of benzaldehyde, and 5.2 mL of boron trifluoride ether were added to the container in sequence under an argon atmosphere, stirred for 2 h, 2 mL of anhydrous methanol was added, and ultrasonic treatment was performed for 30 min. A yellow solid was precipitated, which was filtered and dried to obtain an intermediate product 1.

[0058] Q2: 2.6 g of benzoyl chloride, 2 g of phenylhydrazine and 4.12 g of triethylamine were added to a container containing 8 mL of dichloromethane in sequence, and the mixture was reacted at room temperature for 12 h. After the reaction was completed, 2 mL of 1 mol / L hydrochloric acid was added, and the mixture was extracted with dichloromethane. The organic phase was collected, concentrated under reduced pressure, and purified to obtain compound 1. 1.5 g of compound 1, 4.56 mL of acetonitrile, 4.67 g of triphenylphosphine and 7 mL of carbon tetrachloride were added to a container in sequence, and the mixture was reacted at room temperature for 12 h, and then distilled under reduced pressure and purified to obtain intermediate 2.

[0059] Q3: Add 0.8 g of intermediate product 1 to a container, then add 1 mL of mesitylene, stir, then add 0.83 g of intermediate product 2, heat and stir at 50°C for 6 h. After the reaction, use a mixed solution of petroleum ether and ethyl acetate in a volume ratio of 4:1 as eluent for chromatography purification to obtain an organic antioxidant.

[0060] This embodiment discloses a method for preparing an auxiliary agent, comprising the following steps:

[0061] S1: adding melamine into a crucible, sealing the crucible, and then placing the crucible in a muffle furnace for heating treatment, the process is: heating to 450°C at a heating rate of 2°C / min, maintaining for 4 hours, cooling after heating, grinding, and obtaining a solid catalyst;

[0062] S2: Add 20g of methyl ricinoleate and 80mL of isopropanol into a container, stir and mix evenly, then add 20g of sodium bisulfite into 75mL of distilled water, stir and add into the container, then add 2.5g of solid catalyst, heat and stir at 40℃ for 24h, stir well, cool after stirring, filter, extract with petroleum ether, rotary evaporate, add anhydrous ethanol for desalination, recrystallize, dry to obtain an auxiliary agent.

[0063] This embodiment discloses a distillation purification method for preparing a silane coupling agent, comprising the following steps:

[0064] Step 1: 15 g of crude silane coupling agent, 8 mL of tetrahydrofuran, 0.1 g of organic antioxidant and 0.2 g of auxiliary agent were mixed, heated at 50° C. and stirred for 4 h to obtain a mixture;

[0065] Step 2: Add the mixture to a distillation tower, heat and distill, control the heating temperature and distillation rate to ensure smooth and continuous distillation and condensation of the silane coupling agent;

[0066] Step 3: Collect the condensed liquid into a collector, separate the liquid, filter, and dry to obtain a silane coupling agent.

[0067] Example 4: This example discloses a method for preparing an organic antioxidant, comprising the following steps:

[0068] Q1: 11.92 g of indole was added to a container, followed by 13.57 mL of p-toluenesulfonyl azide, and the mixture was heated at 70°C for condensation and reflux for 12 h. After the reflux was completed, 1.2 mL of anhydrous methanol was added, stirred for 45 min, and filtered to obtain a pink solid. 1.5 g of the pink solid, 10 mL of dichloromethane, 1.55 mL of benzaldehyde, and 3.1 mL of boron trifluoride ether were added to the container in sequence under an argon atmosphere, stirred for 2 h, 2.15 mL of anhydrous methanol was added, and ultrasonic treatment was performed for 30 min. A yellow solid was precipitated, which was filtered and dried to obtain an intermediate product 1.

[0069] Q2: 1.62 g of benzoyl chloride, 1.2 g of phenylhydrazine and 2.53 g of triethylamine were added to a container containing 6 mL of dichloromethane in sequence, and reacted at room temperature for 12 h. After the reaction was completed, 2 mL of 1 mol / L hydrochloric acid was added, and the mixture was extracted with dichloromethane. The organic phase was collected, concentrated under reduced pressure, and purified to obtain compound 1. 1.1 g of compound 1, 3.47 mL of acetonitrile, 2.92 g of triphenylphosphine and 5 mL of carbon tetrachloride were added to a container in sequence, and reacted at room temperature for 12 h, and then distilled under reduced pressure and purified to obtain intermediate 2;

[0070] Q3: Add 0.6 g of intermediate product 1 to a container, then add 0.6 mL of mesitylene, stir, then add 0.71 g of intermediate product 2, heat and stir at 50°C for 6 h. After the reaction, use a mixed solution of petroleum ether and ethyl acetate in a volume ratio of 4:1 as eluent for chromatography purification to obtain an organic antioxidant.

[0071] This embodiment discloses a method for preparing an auxiliary agent, comprising the following steps:

[0072] S1: adding melamine into a crucible, sealing the crucible, and then placing the crucible in a muffle furnace for heating treatment, the process is: heating to 450°C at a heating rate of 2°C / min, maintaining for 4 hours, cooling after heating, grinding, and obtaining a solid catalyst;

[0073] S2: Add 13g of methyl ricinoleate and 60mL of isopropanol into a container, stir and mix evenly, then add 16g of sodium bisulfite into 55mL of distilled water, stir and add into the container, then add 2.1g of solid catalyst, heat and stir at 40℃ for 24h, stir well, cool after stirring, filter, extract with petroleum ether, rotary evaporate, add anhydrous ethanol for desalination, recrystallize, dry to obtain an auxiliary agent.

[0074] This embodiment discloses a distillation purification method for preparing a silane coupling agent, comprising the following steps:

[0075] Step 1: 11 g of crude silane coupling agent, 6 mL of tetrahydrofuran, 0.4 g of organic antioxidant and 0.1 g of auxiliary agent were mixed, heated at 50° C. and stirred for 4 h to obtain a mixture;

[0076] Step 2: Add the mixture to a distillation tower, heat and distill, control the heating temperature and distillation rate to ensure smooth and continuous distillation and condensation of the silane coupling agent;

[0077] Step 3: Collect the condensed liquid into a collector, separate the liquid, filter, and dry to obtain a silane coupling agent.

[0078] Example 5: This example discloses a method for preparing an organic antioxidant, comprising the following steps:

[0079] Q1: 16.68 g of indole was added to a container, followed by 18.99 mL of p-toluenesulfonyl azide, and the mixture was heated at 70°C for condensation and reflux for 12 h. After the reflux was completed, 1.7 mL of anhydrous methanol was added, stirred for 45 min, and filtered to obtain a pink solid. 2.1 g of the pink solid, 14 mL of dichloromethane, 2.3 mL of benzaldehyde, and 4.5 mL of boron trifluoride ether were added to the container in sequence under an argon atmosphere, stirred for 2 h, 2.58 mL of anhydrous methanol was added, and ultrasonic treatment was performed for 30 min. A yellow solid was precipitated, which was filtered and dried to obtain an intermediate product 1.

[0080] Q2: 2.25 g of benzoyl chloride, 1.7 g of phenylhydrazine and 3.59 g of triethylamine were added to a container containing 7 mL of dichloromethane in sequence, and the mixture was reacted at room temperature for 12 h. After the reaction was completed, 2 mL of 1 mol / L hydrochloric acid was added, and the mixture was extracted with dichloromethane. The organic phase was collected, concentrated under reduced pressure, and purified to obtain compound 1. 1.4 g of compound 1, 4.13 mL of acetonitrile, 4.54 g of triphenylphosphine and 6 mL of carbon tetrachloride were added to a container in sequence, and the mixture was reacted at room temperature for 12 h, and then distilled under reduced pressure and purified to obtain intermediate 2.

[0081] Q3: Add 0.7 g of intermediate product 1 to a container, then add 0.8 mL of mesitylene, stir, then add 0.81 g of intermediate product 2, heat and stir at 50°C for 6 h. After the reaction, use a mixed solution of petroleum ether and ethyl acetate in a volume ratio of 4:1 as eluent for chromatography purification to obtain an organic antioxidant.

[0082] This embodiment discloses a method for preparing an auxiliary agent, comprising the following steps:

[0083] S1: adding melamine into a crucible, sealing the crucible, and then placing the crucible in a muffle furnace for heating treatment, the process is: heating to 450°C at a heating rate of 2°C / min, maintaining for 4 hours, cooling after heating, grinding, and obtaining a solid catalyst;

[0084] S2: Add 18g of methyl ricinoleate and 70mL of isopropanol into a container, stir and mix evenly, then add 18g of sodium bisulfite into 70mL of distilled water, stir and add into the container, then add 2.4g of solid catalyst, heat and stir at 40℃ for 24h, stir well, cool after stirring, filter, extract with petroleum ether, rotary evaporate, add anhydrous ethanol for desalination, recrystallize, dry to obtain an auxiliary agent.

[0085] This embodiment discloses a distillation purification method for preparing a silane coupling agent, comprising the following steps:

[0086] Step 1: 14 g of crude silane coupling agent, 7 mL of tetrahydrofuran, 0.2 g of organic antioxidant and 0.15 g of auxiliary agent were mixed, heated at 50° C. and stirred for 4 h to obtain a mixture;

[0087] Step 2: Add the mixture to a distillation tower, heat and distill, control the heating temperature and distillation rate to ensure smooth and continuous distillation and condensation of the silane coupling agent;

[0088] Step 3: Collect the condensed liquid into a collector, separate the liquid, filter, and dry to obtain a silane coupling agent.

[0089] Comparative Example 1: Compared with Example 1, in the preparation process of the organic antioxidant in Comparative Example 1, no benzoyl chloride is added, and other conditions remain unchanged.

[0090] Comparative Example 2: Compared with Example 1, in Comparative Example 2, during the preparation of the auxiliary agent, methyl ricinoleate was not added, and other conditions remained unchanged.

[0091] Comparative Example 3: Compared with Example 1, in Comparative Example 3, no organic antioxidant is added during the distillation and purification process, and other conditions remain unchanged.

[0092] Comparative Example 4: Compared with Example 1, in Comparative Example 4, no auxiliary agent is added during the distillation and purification process, and other conditions remain unchanged.

[0093] Experimental Example: The main component content of the sample was tested by high performance liquid chromatography. According to the yield = (mass of the purified product / mass of the crude product) × 100%, the test results are shown in Table 1:

[0094] Table 1

[0095]

[0096]

[0097] It can be seen from the test results in Table 1 that the silane coupling agent obtained in Examples 1-5 of the present invention has excellent yield and purity. Comparison between Comparative Example 1 and Examples 1-5 shows that the addition of benzoyl chloride can improve the yield and purity of the silane coupling agent; comparison between Comparative Example 2 and Examples 1-5 shows that the addition of methyl ricinoleate can improve the yield and purity of the silane coupling agent; comparison between Comparative Example 3 and Examples 1-5 shows that the addition of an organic antioxidant can improve the yield and purity of the silane coupling agent; comparison between Comparative Example 4 and Examples 1-5 shows that the addition of an auxiliary agent can improve the yield and purity of the silane coupling agent.

[0098] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

[0099] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A distillation purification method for preparing a silane coupling agent, characterized in that: The following steps are involved: Step 1: Mix the crude silane coupling agent, tetrahydrofuran, an organic antioxidant and an auxiliary agent, heat, mix and stir to obtain a mixture; Among them, the structural formula of the organic antioxidant is: The structural formula of the additive is: Step 2: adding the mixture into a distillation tower, heating and distilling, controlling the heating temperature and distillation rate to ensure smooth and continuous distillation and condensation of the silane coupling agent; Step 3: Collect the condensed liquid into a collector, separate the liquid, filter, and dry to obtain a silane coupling agent.

2. The distillation purification method for preparing a silane coupling agent according to claim 1, characterized in that: In the step 1, the usage ratio of the crude silane coupling agent, tetrahydrofuran, organic antioxidant and auxiliary agent is (10-15) g: (5-8) mL: (0.1-0.5) g: (0.05-0.2) g, the heating temperature is 40-50° C., and the heating time is 4-6 h.

3. The distillation purification method for preparing a silane coupling agent according to claim 1, characterized in that: The preparation method of the organic antioxidant comprises the following steps: Q1: Add indole to a container, then add p-toluenesulfonyl azide, heat to condense and reflux, add anhydrous methanol after reflux, stir, filter, and obtain a pink solid, add the pink solid, dichloromethane, benzaldehyde and boron trifluoride ether to the container in sequence under argon atmosphere, stir to react, add anhydrous methanol, ultrasonically treat, a yellow solid precipitates, filter, and dry to obtain intermediate 1; Q2: Add benzoyl chloride, phenylhydrazine and triethylamine to a container containing dichloromethane in sequence, react at room temperature, add hydrochloric acid after the reaction is completed, extract, collect the organic phase, concentrate under reduced pressure, and purify to obtain compound 1, add compound 1, acetonitrile, triphenylphosphine and carbon tetrachloride to a container in sequence, react at room temperature, distill under reduced pressure, and purify to obtain intermediate 2; Q3: Add intermediate product 1 to a container, then add mesitylene, stir, then add intermediate product 2, heat and stir to react, after the reaction is completed, purify by chromatography to obtain an organic antioxidant.

4. The distillation purification method for preparing a silane coupling agent according to claim 3, characterized in that: In the Q1, the dosage ratio of indole, p-toluenesulfonyl azide and anhydrous methanol is (9.53-19.06) g: (10.85-21.7) mL: (1-2) mL, the heating condensation reflux temperature is 60-70°C, the reflux time is 10-12 h, the stirring time is 30-45 min, the dosage ratio of pink solid, dichloromethane, benzaldehyde, boron trifluoride ether and anhydrous methanol is (1.2-2.4) g: (8-16) mL: (1.3-2.6) mL: (2.6-5.2) mL: (2-2.7) mL, the stirring reaction time is 1-2 h, and the ultrasonic treatment time is 30-45 min.

5. The distillation purification method for preparing a silane coupling agent according to claim 3, characterized in that: In Q2, the dosage ratio of benzoyl chloride, phenylhydrazine, triethylamine and dichloromethane is (1.3-2.6) g: (1-2) g: (2.06-4.12) g: (5-8) mL, the reaction time at room temperature is 10-12 h, the concentration of hydrochloric acid is 1 mol / L, and dichloromethane is used for extraction. The dosage ratio of compound 1, acetonitrile, triphenylphosphine and carbon tetrachloride is (1-1.5) g: (3.12-4.56) mL: (2.34-4.67) g: (4-7) mL, and the reaction time at room temperature is 12-14 h.

6. The distillation purification method for preparing a silane coupling agent according to claim 3, characterized in that: In Q3, the usage ratio of intermediate product 1, mesitylene and intermediate product 2 is (0.5-0.8) g: (0.5-1) mL: (0.67-0.83) g, the heating temperature is 40-50°C, the reaction time is 6-8h, and a mixed solution of petroleum ether and ethyl acetate in a volume ratio of 4:1 is used as the eluent for chromatography purification.

7. The distillation purification method for preparing a silane coupling agent according to claim 1, characterized in that: The preparation method of the auxiliary agent comprises the following steps: S1: adding melamine into a crucible, sealing the crucible, and then placing the crucible in a muffle furnace for heating. After the heating is completed, cooling and grinding are performed to obtain a solid catalyst; S2: Add methyl ricinoleate and isopropanol into a container, stir and mix evenly, add sodium bisulfite into distilled water, stir and add into the container, then add solid catalyst, heat and stir, stir thoroughly, cool, filter, extract, rotary evaporate, desalinate, recrystallize, and dry to obtain an auxiliary agent.

8. The distillation purification method for preparing a silane coupling agent according to claim 7, characterized in that: In S1, the heating process is: heating to 450° C. at a heating rate of 2° C. / min and maintaining for 4 hours.

9. The distillation purification method for preparing a silane coupling agent according to claim 7, characterized in that: In S2, the dosage ratio of methyl ricinoleate, isopropanol, sodium bisulfite, distilled water and solid catalyst is (11-20) g: (50-80) mL: (14.5-20) g: (50-75) mL: (2-2.5) g, the heating temperature is 40-50° C., the stirring time is 20-24 h, extraction is performed with petroleum ether, and anhydrous ethanol is added for desalination.

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