Process for the preparation of long chain alkyl green silane coupling agents

Abstract

The application discloses a preparation method of long-chain alkyl green silane coupling agent, comprising the following steps: step one, 10-undecene-1-ol is reacted with chlorosulfoxide under the conditions of low-temperature dropwise adding and medium-temperature preservation, and 11-chloro-1-undecene is obtained through vacuum rectification purification; step two, under the action of a platinum catalyst, 11-chloro-1-undecene is subjected to addition reaction with trichlorosilane, excessive raw materials are removed, and 11-chloro undecyl trichlorosilane is obtained through rectification; step three, 11-chloro undecyl trichlorosilane is subjected to alkoxylation reaction with biological methanol or biological ethanol, by-products and excessive biological alcohol are removed, and high-purity long-chain alkyl green silane coupling agent is obtained through rectification. The carbon sources of raw materials are all biological, the method is green and low-carbon, the product has a long-chain structure, and the product has flexibility, fatigue resistance and aging resistance, and can be further derived into functional silane such as amino, mercapto and thiocyanogen; the long-chain alkyl green silane coupling agent can be widely applied to high-end flexible composite materials such as flexible electronics and robot joints, and effectively improves the service life and safety of the materials.

Description

Technical Field

[0001] This invention relates to the field of coupling agent technology, and specifically to a method for preparing a long-chain alkyl green silane coupling agent. Background Technology

[0002] As human society rapidly advances towards digitalization and artificial intelligence, intelligent robots are widely used in numerous fields such as industrial manufacturing, healthcare, services, and specialized operations. This places higher demands on the supporting additives used in the development of flexible electronic materials, robot telescopic structures, movable joints, and highly elastic sealing materials.

[0003] Silane coupling agents are key interfacial agents for connecting inorganic materials and organic polymers, directly affecting the strength, toughness, aging resistance, service life, and safety of composite materials. Traditional silane coupling agents are mostly short-chain alkyl or functional silanes, with short carbon chains and poor flexibility. Under repeated bending, stretching, and deformation conditions, they are prone to interfacial debonding, cracking, and aging failure, resulting in short lifespan and low safety of robot components, making it difficult to meet the requirements of high-end flexible and dynamic structures.

[0004] Meanwhile, traditional silane coupling agents mostly rely on petroleum-based carbon sources, resulting in high carbon emissions, which is inconsistent with the trend of green and low-carbon development. Therefore, developing long-chain alkyl silane coupling agents with green carbon sources, suitable chain lengths, and excellent flexibility has significant application value. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems of short chains, insufficient performance, and non-green raw materials in the prior art of silane coupling agents, and to provide a method for preparing long-chain alkyl green silane coupling agents.

[0006] To achieve the above objectives, the technical solution provided by this invention is: a method for preparing long-chain alkyl green silane coupling agents, comprising the following steps: Step 1: Add 10-undecen-1-ol to a dry reaction vessel. Under nitrogen protection, stir and cool to 0-10°C, then slowly add thionyl chloride dropwise. Control the dropwise temperature to not exceed 20°C. After the dropwise addition is complete, slowly raise the temperature to 30-50°C and maintain the reaction for 2-6 hours. Monitor the reaction of 10-undecen-1-ol with TLC or gas chromatography until it is complete. After the reaction is complete, remove excess thionyl chloride and byproducts hydrogen chloride and sulfur dioxide gas under reduced pressure to obtain crude 11-chloro-1-undecene (undecene chloride). Purify the crude product by reduced pressure distillation to obtain high-purity undecene chloride. Step 2: Under nitrogen protection and anhydrous and oxygen-free conditions, undecyl chloride is added to trichlorosilane using chloroplatinic acid or cassiterite as a catalyst. The reaction temperature is 50–90°C, the reaction pressure is atmospheric pressure to 0.3 MPa, and the reaction time is 3–8 h. After the reaction is completed, excess trichlorosilane is removed, and 11-chloroundecyltrichlorosilane is obtained by vacuum distillation. Step 3: Add 11-chloroundecyltrichlorosilane to the dry reaction vessel, purge with nitrogen to maintain anhydrous and oxygen-free conditions, control the temperature at 0–30°C, and slowly add bio-methanol or bioethanol dropwise. After the addition is complete, raise the temperature to 30–60°C and maintain the reaction temperature for 2–6 hours until the raw material trichlorosilane intermediate is obtained. Remove hydrogen chloride gas and excess bioethanol under reduced pressure to obtain crude 11-chloroundecyltrimethoxysilane or 11-chloroundecyltriethoxysilane. The crude product is then subjected to reduced pressure distillation to obtain a high-purity long-chain alkyl green silane coupling agent.

[0007] Preferably, the molar ratio of 10-undecen-1-ol to thionyl chloride in this invention is 1:1.05 to 1.30.

[0008] Preferably, the ratio of undecyl chloride to trichlorosilane in the present invention is 1:1.05 to 1.5.

[0009] Preferably, the molar ratio of 11-chloroundecyltrichlorosilane to biomethanol or bioethanol in this invention is 1:3.0 to 5.0.

[0010] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention adopts a long-chain undecyl structure. Compared with traditional propylsilane, the silane coupling agent of the present invention has a longer chain, significantly improved flexibility, fatigue resistance and aging resistance.

[0011] 2. The carbon source of the raw materials in this invention is entirely derived from bio-based sources, making it green, low-carbon, and environmentally friendly.

[0012] 3. The process route of this invention is simple, can use microtube reactors, is safer, less prone to explosion, the reaction is controllable, the yield is high, and it is suitable for industrial production.

[0013] 4. The product of this invention is applicable to flexible electronics, robot joints, telescopic materials, and high-elasticity composite materials, significantly improving service life and safety. Detailed Implementation

[0014] The present invention will be further described below with reference to the embodiments. The embodiments of the present invention include, but are not limited to, the following embodiments. Example 1 Under nitrogen protection, 170 g (1.0 mol) of 10-undecen-1-ol was added to a dry reaction vessel. Stirring was started, and the temperature was lowered to 0–10 °C. 143 g (1.2 mol) of thionyl chloride was slowly added dropwise, controlling the dropping temperature to not exceed 20 °C, for 1.5 h. After the addition was complete, the temperature was slowly raised to 40–45 °C, and the reaction was maintained at this temperature with stirring for 4 h. The reaction was stopped when the residual amount of 10-undecen-1-ol was <0.5%, as monitored by gas chromatography (GC). After the reaction was complete, excess thionyl chloride and byproducts SO2 and HCl gases were removed under reduced pressure. The product was then subjected to reduced pressure distillation, and the fraction was collected to obtain 182 g of 11-chloro-1-undecene (undecene chloride) with a purity ≥99.2% and a yield of 91.2%.

[0016] The requirements for the above-mentioned vacuum distillation apparatus are as follows: packed column ≥30 cm (glass spring / θ ring is acceptable), vacuum: oil pump ≤10 mmHg (preferably 1–2 mmHg), distillation head: equipped with reflux ratio controller.

[0017] Vacuum and temperature for reduced pressure distillation: Vacuum 0.01 atm≈10 mmHg, oil bath 140–160°C, distillation temperature (top temperature): undecenyl chloride approximately 95–105 °C, undecenol approximately 120–130 °C. If the top temperature is raised, immediately change the receiving flask.

[0018] Reflux ratio for vacuum distillation: 5:1 for the forerun, 10:1 for the main distillate (undecenyl chloride), 10:1 for the main distillate, and 10:1 for the undecenol. Distillate division: forerun (light impurities, solvent), main distillate A: 10-undecenyl chloride (99%+), intermediate distillate (recycled), main distillate B: 10-undecenol (99%+).

[0019] Example 2 Under nitrogen protection and anhydrous and oxygen-free conditions, 199 g (1.0 mol) of undecene chloride prepared in Example 1 was added to a dry reaction vessel, along with a chloroplatinic acid catalyst (10 ppm, calculated as platinum). After stirring until homogeneous, 149 g (1.2 mol) of trichlorosilane was slowly added, controlling the addition rate to avoid a sudden rise in system temperature. After the addition was complete, the temperature was raised to 70 °C and the reaction was maintained at this temperature for 5 h. The reaction endpoint was determined by GC monitoring showing that the residual amount of undecene chloride was <0.5%. After the reaction was completed, excess trichlorosilane was removed under reduced pressure (and recycled). The crude product was then subjected to reduced pressure distillation to obtain 296 g of 11-chloroundecyltrichlorosilane with a purity ≥98% and a yield of 89.5%.

[0020] The above-mentioned reduced pressure distillation adopts high vacuum distillation, and the high vacuum distillation conditions are 112 ℃ / 0.01 mmHg.

[0021] Example 3 Under nitrogen protection and an anhydrous environment, 331 g (1.0 mol) of 11-chloroundecyltrichlorosilane prepared in Example 2 was added to a dry reaction vessel. The system temperature was controlled at 0–20 °C, and 68 g (2.125 mol) of bio-methanol was slowly added dropwise, with the temperature controlled not to exceed 25 °C during the addition process, and the addition time was 1 h. After the addition was completed, the temperature was raised to 40–50 °C and the reaction was maintained at this temperature for 4 h. The reaction was stopped when the residual amount of 11-chloroundecyltrichlorosilane was <0.5% by GC monitoring. After the reaction was completed, HCl gas and excess bio-methanol were removed under reduced pressure. The crude product was then subjected to reduced pressure distillation to obtain 312 g of 11-chloroundecyltrimethoxysilane with a purity ≥98% and a yield of 90.1%.

[0022] Example 4 Following the process of Example 3, only 92g (2.0mol) of bioethanol was replaced with biomethanol, the molar ratio of 11-chloroundecyltrichlorosilane to bioethanol was 1:2.0, and other reaction conditions remained unchanged, to obtain 344g of 11-chloroundecyltriethoxysilane with a purity ≥98% and a yield of 89.7%.

[0023] Example 5 346 g (1.0 mol) of 11-chloroundecyltrimethoxysilane prepared in Example 3 was added to a dry reaction vessel, along with 500 mL of methanol as solvent. After purging with nitrogen three times, ammonia gas was slowly introduced at room temperature (molar ratio of 11-chloroundecyltrimethoxysilane to ammonia = 1:10). After the ammonia gas was introduced, the temperature was raised to 50 °C and the reaction was maintained at this temperature for 6 h. After the reaction was completed, the mixture was cooled to room temperature, and the byproduct ammonium chloride was removed by filtration. The filtrate was then subjected to vacuum distillation to remove the solvent and excess ammonia, yielding 318 g of 11-aminoundecyltrimethoxysilane with a purity ≥97.5% and a yield of 88.6%.

[0024] Example 6 346 g (1.0 mol) of 11-chloroundecyltrimethoxysilane prepared in Example 3 was added to a dry reaction vessel, along with 500 mL of toluene as a solvent, and then 121 g (1.2 mol) of triethylamine. Under nitrogen protection, the temperature was raised to 70–80 °C and the reaction was maintained for 8 h. The reaction endpoint was determined by GC monitoring showing that the residual amount of the starting material was <0.5%. After the reaction was completed, the mixture was cooled to room temperature, and the generated triethylamine hydrochloride was removed by filtration. The filtrate was then subjected to vacuum distillation to remove the solvent, yielding 298 g of 11-undecyltrimethoxysilane with a purity ≥98% and a yield of 89.3%.

[0025] Example 7 Under nitrogen protection, 346 g (1.0 mol) of 11-chloroundecyltrimethoxysilane prepared in Example 3 was added to a dry reaction vessel, along with 400 mL of acetone as a solvent, and then 128 g (1.2 mol) of methacrylate. The temperature was raised to 55–65 °C and maintained for 7 h. GC monitoring confirmed complete reaction of the raw materials. After the reaction, the generated salt impurities were removed by filtration. The filtrate was then subjected to vacuum distillation to remove the solvent, and the crude product was subjected to vacuum distillation to obtain 362 g of 11-methacryloyloxyundecyltrimethoxysilane with a purity ≥97.5% and a yield of 87.9%.

[0026] Example 8 346 g (1.0 mol) of 11-chloroundecyltrimethoxysilane prepared in Example 3 was added to a dry reaction vessel, along with 300 mL of ethanol as a solvent. The temperature was controlled at 25–35 °C, and 340 g (1.2 mol) of 20% hydrogen polysulfide solution was slowly added dropwise. After the addition was complete, the reaction was maintained at this temperature for 5 h. After the reaction was completed, the liquid was separated, and the organic phase was washed twice with saturated brine, dried over anhydrous magnesium sulfate, filtered, and the solvent was removed under reduced pressure. The solution was then subjected to reduced pressure distillation, and the corresponding fractions were collected to obtain 192 g (purity ≥97%) of undecylsilane disulfide and 185 g (purity ≥97%) of undecylsilane tetrasulfide, with a total yield of 88.2%.

[0027] Example 9 Step 1: 346 g (1.0 mol) of 11-chloroundecyltrimethoxysilane prepared in Example 3 was added to a dry reaction vessel, along with 400 mL of isopropanol as a solvent and 56 g (1.1 mol) of sodium hydrosulfide. The mixture was heated to 45–55 °C and reacted for 4 h. GC monitoring was used to ensure the reaction was complete. After the reaction, the generated sodium chloride was removed by filtration. The filtrate was then subjected to vacuum distillation to remove the solvent, yielding 322 g of 11-mercaptoundecyltrimethoxysilane with a purity ≥98% and a yield of 89.8%.

[0028] Step 2: To the prepared 11-mercaptoundecyltrimethoxysilane (358 g, 1.0 mol), add 400 mL of dichloromethane as a solvent. Under nitrogen protection, cool to 0–5 °C and slowly add 215 g (1.05 mol) of undecyl chloride. After the addition is complete, raise the temperature to 25–30 °C and maintain the reaction temperature for 3 hours. After the reaction is complete, wash with saturated sodium bicarbonate solution until neutral, then wash once with saturated brine, dry with anhydrous magnesium sulfate, filter, remove solvent under reduced pressure, and distill under reduced pressure to obtain 486 g of undecylmercaptoundecylsilane with a purity ≥97% and a yield of 88.5%.

[0029] Example 10 Under nitrogen protection, 346 g (1.0 mol) of 11-chloroundecyltrimethoxysilane prepared in Example 3 was added to a dry reaction vessel, along with 400 mL of acetonitrile as a solvent and 81 g (1.05 mol) of sodium thiocyanate. The temperature was raised to 60–70 °C and the reaction was maintained at this temperature for 6 h. The reaction endpoint was defined as the residual amount of raw materials being <0.5% as monitored by GC. After the reaction was completed, the mixture was cooled to room temperature, and the generated sodium chloride was removed by filtration. The filtrate was then subjected to vacuum distillation to remove the solvent, and the crude product was subjected to vacuum distillation to obtain 342 g of 11-thiocyanoundecyltrimethoxysilane with a purity ≥97.5% and a yield of 89.1%.

[0030] The above embodiments are merely preferred embodiments of the present invention and should not be used to limit the scope of protection of the present invention. Any modifications or refinements made to the main design concept and spirit of the present invention that are not of substantial significance, but solve the same technical problem as the present invention, should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a long-chain alkyl green silane coupling agent, characterized in that... Includes the following steps: Step 1: Add 10-undecen-1-ol to a dry reaction vessel. Under nitrogen protection, stir and cool to 0-10°C, then slowly add thionyl chloride dropwise. Control the dropwise temperature to not exceed 20°C. After the dropwise addition is complete, slowly raise the temperature to 30-50°C and maintain the reaction for 2-6 hours. Monitor the reaction of 10-undecen-1-ol with TLC or gas chromatography until it is complete. After the reaction is complete, remove excess thionyl chloride and byproducts hydrogen chloride and sulfur dioxide gas under reduced pressure to obtain crude 11-chloro-1-undecene (undecene chloride). Purify the crude product by reduced pressure distillation to obtain high-purity undecene chloride. Step 2: Under nitrogen protection and anhydrous and oxygen-free conditions, undecyl chloride is added to trichlorosilane using chloroplatinic acid or cassiterite as a catalyst. The reaction temperature is 50–90°C, the reaction pressure is atmospheric pressure to 0.3 MPa, and the reaction time is 3–8 h. After the reaction is completed, excess trichlorosilane is removed, and 11-chloroundecyltrichlorosilane is obtained by vacuum distillation. Step 3: Add 11-chloroundecyltrichlorosilane to the dry reaction vessel, purge with nitrogen to maintain anhydrous and oxygen-free conditions, control the temperature at 0–30°C, and slowly add bio-methanol or bioethanol dropwise. After the addition is complete, raise the temperature to 30–60°C and maintain the reaction temperature for 2–6 hours until the raw material trichlorosilane intermediate is obtained. Remove hydrogen chloride gas and excess bioethanol under reduced pressure to obtain crude 11-chloroundecyltrimethoxysilane or 11-chloroundecyltriethoxysilane. The crude product is then subjected to reduced pressure distillation to obtain a high-purity long-chain alkyl green silane coupling agent.

2. The method for preparing the long-chain alkyl green silane coupling agent according to claim 1, characterized in that: The molar ratio of 10-undecen-1-ol to thionyl chloride is 1:1.05 to 1.

30.

3. The method for preparing the long-chain alkyl green silane coupling agent according to claim 1, characterized in that: The ratio of undecyl chloride to trichlorosilane is 1:1.05 to 1.

5.

4. The method for preparing the long-chain alkyl green silane coupling agent according to claim 1, characterized in that: The molar ratio of the 11-chloroundecyltrichlorosilane to biomethanol or bioethanol is 1:3.0 to 5.0.