Preparation method of cyclohexylmethyldimethoxysilane
By carrying out a hydrosilylation reaction and esterification tower purification under a mixed atmosphere of oxygen and nitrogen, the problems of low yield and industrial applicability of cyclohexylmethyldimethoxysilane were solved, and the preparation of high purity and high yield was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANDONG GUIKE NEW MATERIAL CO LTD
- Filing Date
- 2026-01-27
- Publication Date
- 2026-05-12
AI Technical Summary
Existing methods for preparing cyclohexylmethyldimethoxysilane suffer from low yields, complex processes, and unsuitability for industrial production. In particular, the Grignard reagent method and the alkali metal method pose safety hazards and impurity contamination, while the hydrosilylation method yields less than 70%.
A hydrosilylation reaction was carried out under a mixed atmosphere of oxygen and nitrogen to produce cyclohexylmethyldichlorosilane, which was then subjected to a substitution reaction with methanol. The cyclohexylmethyldimethoxysilane was obtained by dropwise addition and purification in an esterification tower.
High purity and high yield of cyclohexylmethyldimethoxysilane were achieved, with a purity of over 99% and a yield of over 85%, avoiding safety hazards and impurity contamination.
Smart Images
Figure CN122011007A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of organic synthesis technology, specifically relating to a method for preparing cyclohexylmethyldimethoxysilane. Background Technology
[0002] Cyclohexylmethyldimethoxysilane is a class of silane coupling agents containing a six-membered ring. It can be used as an auxiliary agent for highly efficient supported catalysts in propylene polymerization and is widely applied in the production of plastics such as polypropylene and polyethylene. Furthermore, this compound can also be used in the synthesis and modification of other organosilicon compounds.
[0003] Currently, the main methods for preparing cyclohexylmethyldimethoxysilane are the Grignard reagent method, the hydrosilylation method, and the alkali metal method. The Grignard reagent method requires organic reagents, thus increasing the variety of reactants and lengthening the process route. It also easily introduces new impurities during synthesis, and most organic solvents are highly toxic, potentially harming human health, making it unsuitable for industrial production. The alkali metal method uses some highly reactive and hazardous metals, also making it difficult to transfer to industrial production. The hydrosilylation method is currently the best-controlled process; however, existing methods using hydrosilylation yield cyclohexylmethyldimethoxysilanes with low yields, only 70-80%. Summary of the Invention
[0004] In view of this, the present invention provides a method for preparing cyclohexylmethyldimethoxysilane. The cyclohexylmethyldimethoxysilane prepared according to the method provided by the present invention has high purity and high yield.
[0005] To address the aforementioned technical problems, this invention provides a method for preparing cyclohexylmethyldimethoxysilane, comprising the following steps: Cyclohexene, methyldichlorosilane, and a platinum catalyst were mixed in a mixed atmosphere of oxygen and nitrogen and then subjected to a hydrosilylation reaction to obtain cyclohexylmethyldichlorosilane; the oxygen content in the mixed atmosphere of oxygen and nitrogen was 100~200ppm. The cyclohexylmethyldichlorosilane was mixed with methanol and subjected to a substitution reaction. The system after the substitution reaction was purified to obtain the cyclohexylmethyldimethoxysilane.
[0006] Preferably, the oxygen content in the mixed atmosphere of oxygen and nitrogen is 110~150ppm.
[0007] Preferably, the molar ratio of cyclohexene to methyldichlorosilane is 1:1 to 1.2; The content of platinum catalyst in the mixture of cyclohexene, methyldichlorosilane and platinum catalyst is 5~200ppm.
[0008] Preferably, the temperature of the hydrosilylation reaction is 110~120℃, and the time of the hydrosilylation reaction is 2~3h.
[0009] Preferably, the substitution reaction is carried out in an esterification column, which includes a packed column at the top and a receiving vessel at the bottom; a first dropping device is provided in the packed column, a condenser is connected above the packed column, and a second dropping device is provided at the connection between the packed column and the receiving vessel.
[0010] Preferably, cyclohexylmethyldichlorosilane is added dropwise to the packed column using a first dropping device, and methanol is added dropwise to the receiving vessel using a second dropping device; The dropping rate of methanol is 3~50 mL / min; The dropping rate of cyclohexylmethyldichlorosilane was 5~50 mL / min.
[0011] Preferably, the temperature of the receiving vessel is 100~140℃; the temperature in the packing column is 120~130℃. The substitution reaction takes 0.5 to 1.5 hours.
[0012] Preferably, the purification process includes sequentially subjecting the system after the substitution reaction to vacuum treatment, neutralization, and fractionation.
[0013] Preferably, the vacuum degree of the vacuum treatment is 700~730 mmHg; the vacuum treatment time is 0.5~3h, and the temperature is 50~90℃.
[0014] Preferably, the neutralization involves mixing a sodium methoxide methanol solution with a mass concentration of 18-22% with the vacuum-treated system; the mass ratio of the vacuum-treated system to the sodium methoxide methanol solution is 2.5-5:1.
[0015] This invention provides a method for preparing cyclohexylmethyldimethoxysilane, comprising the following steps: a hydrosilylation reaction is carried out by mixing cyclohexene, methyldichlorosilane, and a platinum catalyst under a mixed atmosphere of oxygen and nitrogen to obtain cyclohexylmethyldichlorosilane; the oxygen content in the mixed atmosphere of oxygen and nitrogen is 100-200 ppm; the cyclohexylmethyldichlorosilane is then mixed with methanol to carry out a substitution reaction; the system after the substitution reaction is purified to obtain the cyclohexylmethyldimethoxysilane. The cyclohexylmethyldimethoxysilane prepared according to the method provided by this invention has high purity and yield. Attached Figure Description
[0016] Figure 1 The image shows a gas chromatogram of cyclohexylmethyldimethoxysilane prepared in Example 1. Detailed Implementation
[0017] This invention provides a method for preparing cyclohexylmethyldimethoxysilane, comprising the following steps: Cyclohexene, methyldichlorosilane, and a platinum catalyst were mixed in a mixed atmosphere of oxygen and nitrogen and then subjected to a hydrosilylation reaction to obtain cyclohexylmethyldichlorosilane; the oxygen content in the mixed atmosphere of oxygen and nitrogen was 100~200ppm. The cyclohexylmethyldichlorosilane was mixed with methanol and subjected to a substitution reaction. The system after the substitution reaction was purified to obtain the cyclohexylmethyldimethoxysilane.
[0018] This invention involves a hydrosilylation reaction of cyclohexene, methyldichlorosilane, and a platinum catalyst under a mixed atmosphere of oxygen and nitrogen to yield cyclohexylmethyldichlorosilane. In this invention, the oxygen content in the mixed atmosphere is 100-200 ppm, specifically 125-135 ppm, and more precisely, 130 ppm. The oxygen can serve as a catalyst aid, and the use of a mixed atmosphere of oxygen and nitrogen reduces safety hazards during operation.
[0019] In one specific embodiment of the present invention, the molar ratio of cyclohexene and methyldichlorosilane can be 1:1 to 1.2, specifically 1:1.1; the content of platinum catalyst in the mixed system of cyclohexene, methyldichlorosilane and platinum catalyst can be 5 to 200 ppm, or 9 to 100 ppm, specifically 10 ppm, 50 ppm or 80 ppm.
[0020] This invention does not have special requirements for the mixing of cyclohexene, methyldichlorosilane, and platinum catalyst, as long as they are mixed uniformly. In one specific embodiment of this invention, the temperature of the hydrosilylation reaction can be 110-120°C, specifically 113°C, 115°C, or 118°C; the time of the hydrosilylation reaction can be 2-3 hours, specifically 2.3 hours, 2.5 hours, or 2.8 hours. In this invention, the hydrosilylation reaction is stopped when the content of cyclohexylmethyldichlorosilane in the system is 70% or more (it can be 75%) after the hydrosilylation reaction.
[0021] In this invention, the equation for the hydrosilylation reaction is shown in Equation 1: Formula 1.
[0022] In one specific embodiment of the present invention, the hydrosilylation reaction may further include: subjecting the system after the hydrosilylation reaction to atmospheric distillation and vacuum distillation sequentially; the temperature of the atmospheric distillation may be 130-140°C; the temperature of the vacuum distillation may be 130-140°C, the peak temperature of the vacuum distillation may be >45°C, and the vacuum degree of the vacuum distillation may be 700-730 mmHg. The present invention removes methyldichlorosilane through atmospheric distillation and removes cyclohexene through vacuum distillation.
[0023] After obtaining cyclohexylmethyldichlorosilane, the present invention mixes the cyclohexylmethyldichlorosilane with methanol and performs a substitution reaction. The system after the substitution reaction is then purified to obtain the cyclohexylmethyldimethoxysilane. In one specific embodiment of the present invention, the substitution reaction can be carried out in an esterification column, which may include a packed column at the upper part and a receiving vessel at the lower part; a first dropping device is provided at the inlet of the packed column, a condenser is connected to the outlet of the packed column, and a second dropping device is provided at the connection between the packed column and the receiving vessel; the packing material in the packed column may be glass packing. This invention utilizes a first dropping device to add cyclohexylmethyldichlorosilane dropwise into a packed column, and a second dropping device to add methanol dropwise into a receiving vessel. The dropping rate of methanol can be 3~50 mL / min, or 6~6.5 mL / min, specifically 6.3 mL / min; the dropping rate of cyclohexylmethyldichlorosilane can be 5~50 mL / min, or 10~30 mL / min, specifically 12.87 mL / min; the temperature of the receiving vessel can be 100~140℃, and the temperature in the packed column can be 120~130℃, specifically 125℃. In one specific embodiment of this invention, the substitution reaction time can be 0.5~1.5 h, specifically 1 h or 1.3 h.
[0024] In this invention, the equation for the substitution reaction is shown in Equation 2: Equation 2.
[0025] In one specific embodiment of the present invention, the purification process may include sequentially subjecting the system after the substitution reaction to vacuum treatment, neutralization, and fractionation; the vacuum degree of the vacuum treatment may be 700-730 mmHg; the vacuum treatment temperature may be 50-90°C, specifically 60°C, 70°C, or 80°C; the vacuum treatment time may be 0.5-3 hours, specifically 1 hour, 1.5 hours, 2 hours, or 2.5 hours. The present invention, through vacuum treatment, can remove the acid (HCl) generated in the reaction and the incompletely reacted methanol.
[0026] In one specific embodiment of the present invention, the neutralization involves mixing a sodium methoxide methanol solution with a mass concentration of 18-22% with the vacuum-treated system; the mass ratio of the vacuum-treated system to the sodium methoxide methanol solution is 2.5-5:1 (specifically 3:1, 3.5:1, 4:1, or 4.5:1); the mass concentration of sodium methoxide in the sodium methoxide methanol solution can be 18-22%, specifically 20%; the pH value of the system after neutralization is approximately 7. In this invention, the fractionation temperature can be 100-180°C, specifically, the finished product is received at 100°C and the fractionation operation is completed at 180°C; in this invention, the sodium methoxide can neutralize chloride ions in the system.
[0027] The cyclohexylmethyldimethoxysilane prepared according to the preparation method provided by the present invention has a purity of 99% or higher, specifically 99.84%; and a yield of 85% or higher, specifically 90%.
[0028] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.
[0029] Example 1 Cyclohexene, methyldichlorosilane, and platinum catalyst were added sequentially to a reactor, with a molar ratio of cyclohexene to methyldichlorosilane of 1:1.1 and a platinum catalyst concentration of 10 ppm. The reactor was heated to 120°C for 2.5 h under a mixed atmosphere of oxygen and nitrogen (oxygen concentration of 130 ppm) to initiate a hydrosilylation reaction. The reaction was stopped when the mass percentage of cyclohexylmethyldichlorosilane in the system reached 75% after the hydrosilylation reaction, as determined by gas chromatography. Subsequently, atmospheric distillation was performed at 130–140°C, followed by vacuum distillation at 130–140°C (top temperature > 45°C) and a vacuum of 700–730 mmHg to remove methyldichlorosilane and cyclohexene, yielding cyclohexylmethyldichlorosilane. Esterification tower equipment setup: A heating jacket is installed outside two layers of glass-filled packing columns. A receiving vessel is installed below the packing columns. The outlet of the packing columns is connected to a condenser, and a dropping device is installed at the inlet of the packing columns, as well as at the connection between the packing columns and the receiving vessel. When the receiving vessel is heated to 140℃, methanol is added dropwise to the receiving vessel at a dropping rate of 6.3 mL / min, completing the methanol addition within 3.5 hours. (Cyclohexylmethyldichlorosilane is then added dropwise to the packing columns at a dropping rate of 12.87 mL / min, completing the addition within 3.5 hours.) After the addition is complete, the temperature of the receiving vessel is maintained at 100~105℃ and the temperature of the packed column is maintained at 120~130℃ for 1 hour of substitution reaction. After that, the content of the sample at the bottom of the vessel is tested. Vacuum treatment is carried out at 80℃ for 1 hour under conditions of 700~730mmHg. The vacuum-treated system and a 20% sodium methoxide methanol solution (the mass ratio of the vacuum-treated system and the sodium methoxide methanol solution is 3.5:1) are mixed and fractionated (the fractionated product is collected at 100~180℃) to obtain cyclohexylmethyldimethoxysilane.
[0030] The purity of the prepared cyclohexylmethyldimethoxysilane was 99.84%, and the yield was 90%, as determined by gas chromatography. The cyclohexylmethyldimethoxysilane prepared in Example 1 was analyzed by gas chromatography, and the resulting gas chromatogram is shown below. Figure 1 As shown. By Figure 1 It can be seen that the product obtained in Example 1 is cyclohexylmethyldimethoxysilane.
[0031] Comparative Example 1 The hydrosilylation reaction was carried out according to the method of Example 1, except that the reaction was carried out under a nitrogen atmosphere, as follows: Cyclohexene, methyldichlorosilane, and platinum catalyst were added sequentially to a reactor, with a molar ratio of cyclohexene to methyldichlorosilane of 1:1.1 and a platinum catalyst concentration of 10 ppm. The reactor was heated to 120°C under a nitrogen atmosphere (oxygen content of 0) for 2.5 h for a hydrosilylation reaction. The mass percentage of cyclohexylmethyldichlorosilane in the system after the hydrosilylation reaction was found to be 0, and chromatographic analysis showed that the raw materials did not react significantly.
[0032] Comparative Example 2 The hydrosilylation reaction was carried out according to the method of Example 1, except that the reaction was carried out in a mixed atmosphere of nitrogen and oxygen with relatively high oxygen concentrations (260 ppm and 690 ppm), as follows: Cyclohexene, methyldichlorosilane, and platinum catalyst were added sequentially to a reactor, with a molar ratio of cyclohexene to methyldichlorosilane of 1:1.1 and a platinum catalyst concentration of 10 ppm. The reactor was heated to 120°C for 2.5 hours under a mixed atmosphere of oxygen and nitrogen (oxygen concentrations of 260 ppm and 690 ppm, respectively) to induce a hydrosilylation reaction. The mass percentage of cyclohexylmethyldichlorosilane in the system after the hydrosilylation reaction was measured. When the oxygen concentration was 260 ppm, the mass percentage of cyclohexylmethyldichlorosilane in the system after the hydrosilylation reaction was 65%; when the oxygen concentration was 690 ppm, the mass percentage was 63.31%, both lower than the mass of cyclohexylmethyldichlorosilane produced in Example 1. Extending the reaction time in Comparative Example 2 resulted in a slight increase in the content of cyclohexylmethyldichlorosilane in the system after the hydrosilylation reaction.
[0033] Comparative Example 3 The hydrosilylation reaction was carried out according to the method of Example 1, except that the reaction was carried out in a mixed atmosphere of nitrogen and oxygen with a lower oxygen concentration (73 ppm), as follows: Cyclohexene, methyldichlorosilane, and platinum catalyst were added sequentially to a reactor, with a molar ratio of cyclohexene to methyldichlorosilane of 1:1.1 and a platinum catalyst content of 10 ppm in the mixture. The reactor was heated to 120°C for 2.5 h under a mixed atmosphere of oxygen and nitrogen (oxygen content of 73 ppm) for hydrosilylation reaction. The mass percentage of cyclohexylmethyldichlorosilane in the system after the hydrosilylation reaction was measured to be 50%, which is less than the mass of cyclohexylmethyldichlorosilane produced in Example 1.
[0034] The results above show that the cyclohexylmethyldichlorosilane prepared according to the preparation method provided by the present invention has a high yield, thereby ensuring that the cyclohexylmethyldimethoxysilane has a high yield.
[0035] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.
Claims
1. A method for preparing cyclohexylmethyldimethoxysilane, characterized in that, Includes the following steps: Cyclohexene, methyldichlorosilane, and a platinum catalyst were mixed in a mixed atmosphere of oxygen and nitrogen and then subjected to a hydrosilylation reaction to obtain cyclohexylmethyldichlorosilane; the oxygen content in the mixed atmosphere of oxygen and nitrogen was 100~200ppm. The cyclohexylmethyldichlorosilane was mixed with methanol and subjected to a substitution reaction. The system after the substitution reaction was purified to obtain the cyclohexylmethyldimethoxysilane.
2. The preparation method according to claim 1, characterized in that, The oxygen content in the mixed atmosphere of oxygen and nitrogen is 110~150ppm.
3. The preparation method according to claim 1, characterized in that, The molar ratio of cyclohexene to methyldichlorosilane is 1:1 to 1.2; The content of platinum catalyst in the mixture of cyclohexene, methyldichlorosilane and platinum catalyst is 5~200ppm.
4. The preparation method according to any one of claims 1 to 3, characterized in that, The hydrosilylation reaction is carried out at a temperature of 110~120℃ for 2~3 hours.
5. The preparation method according to claim 1, characterized in that, The substitution reaction is carried out in an esterification column, which includes a packed column at the top and a receiving vessel at the bottom. A first dropping device is provided in the packed column, a condenser is connected above the packed column, and a second dropping device is provided at the connection between the packed column and the receiving vessel.
6. The preparation method according to claim 5, characterized in that, Cyclohexylmethyldichlorosilane was added dropwise to the packed column using the first dropping device, and methanol was added dropwise to the receiving vessel using the second dropping device. The dropping rate of methanol is 3~50 mL / min; The dropping rate of cyclohexylmethyldichlorosilane was 5~50 mL / min.
7. The preparation method according to claim 5 or 6, characterized in that, The temperature of the receiving vessel is 100~140℃; the temperature in the packing column is 120~130℃; The substitution reaction takes 0.5 to 1.5 hours.
8. The preparation method according to claim 1, characterized in that, The purification process includes sequentially subjecting the system after the substitution reaction to vacuum treatment, neutralization, and fractionation.
9. The preparation method according to claim 8, characterized in that, The vacuum degree of the vacuum treatment is 700~730 mmHg; the vacuum treatment time is 0.5~3h, and the temperature is 50~90℃.
10. The preparation method according to claim 8, characterized in that, The neutralization process involves mixing a sodium methoxide methanol solution with a mass concentration of 18-22% with the vacuum-treated system; the mass ratio of the vacuum-treated system to the sodium methoxide methanol solution is 2.5-5:1.