A method for preparing methacryloyloxypropyltris(trimethylsiloxane)silane via a microchannel reactor

Abstract

This invention discloses a method for preparing methacryloxypropyltris(trimethylsiloxane)silane via a microchannel reactor, relating to the field of organic synthesis technology. Using methacryloxypropyltrimethoxysilane and hexamethyldisiloxane as raw materials, a silicone transesterification reaction is completed through a microchannel reactor to obtain crude methacryloxypropyltris(trimethylsiloxane)silane. After separating the monomers (MM) and the product by thin-film evaporation, the target product is obtained by molecular distillation with a purity >99%. This synthesis method significantly improves the reaction rate and lowers the reaction temperature through the microchannel reactor, while also reducing side reactions during transesterification, such as dimers and polymers formed by the condensation of two molecules. These polymers are not polymers produced by the polymerization of acrylic acid double bonds, but rather polysiloxanes formed between silicon, oxygen, and silicon. The purification method is changed from the original distillation and rectification to thin-film evaporation and molecular distillation, transforming the intermittent purification method into a more efficient continuous purification method.

Description

Technical Field

[0001] This invention relates to the field of organic synthesis technology, specifically to a method for preparing methacryloyloxypropyltris(trimethylsiloxane)silane via a microchannel reactor. Background Technology

[0002] Oxygen permeability is a crucial indicator of contact lens comfort, and the introduction of silicon materials represents a breakthrough in improving oxygen permeability. Methacryloxypropyltris(trimethylsiloxane)silane is one of the key monomers for producing high-performance contact lenses. Patent US413954 disclosed the preparation of contact lenses using this material in 1979, and patent US7649598 also reported the application of this compound and similar compounds in contact lenses. Several high-performance products have been developed, such as CooperVision's "Biofinity" and Johnson & Johnson's "Eurocomfort."

[0003] Methacryloxypropyltris(trimethylsiloxane)silane, as a novel product of (meth)acryloyloxysilanes, can be combined with 2-ethyl-2-adamantane methacrylate to form a high-temperature resistant gas separation membrane.

[0004] Methacryloxypropyltris(trimethylsiloxane)silane is emulsion polymerized with other acrylic monomers such as methyl acrylate, butyl acrylate, hydroxyethyl acrylate, etc., to prepare waterproof coatings as a substitute for fluorine-containing waterproof materials.

[0005] Methacryloxypropyltris(trimethylsiloxane)silane can also be added to acrylic adhesive systems to adjust the adhesive peel strength.

[0006] The existing synthetic method for methacryloyloxypropyltris(trimethylsiloxane)silane is as follows:

[0007] CN104910200A discloses the following synthetic route for methacryloxypropyltris(trimethylsiloxane):

[0008]

[0009] Similarly, CN103554169A reports the following synthetic route for methacryloxypropyltris(trimethylsiloxane):

[0010]

[0011] Similarly, CN 103554169A reports the following synthetic route for methacryloxypropyltris(trimethylsiloxane):

[0012]

[0013] The synthesis methods of patents such as WO03 / 064436A1 and US8110697B2 are all very similar. They all use batch reactors for reaction, which cannot be continuously produced. In addition, the raw material costs are high or there is a lot of waste acid as a by-product. This patent has readily available raw materials, less wastewater, and has achieved industrial continuous production.

[0014] In summary, the preparation method of methacryloxypropyltris(trimethylsiloxane)silane uses methacryloxypropyltrimethoxysilane (KH570) and hexamethyldisiloxane as raw materials. The silicone exchange reaction is completed through a microchannel reactor to obtain crude methacryloxypropyltris(trimethylsiloxane)silane. After separating MM and product by membrane evaporation, the target product is obtained by molecular distillation with a purity >99%. Step (1): The mixture A after uniformly mixing of methacryloxypropyltrimethoxysilane (KH570) and hexamethyldisiloxane is mixed with acidic water methanol solution B by metering pumps into a premixer and then reacted in a microchannel reactor to obtain crude methacryloxypropyltris(trimethylsiloxane)silane A. After separation, pH adjustment, drying and filtration, crude product A is purified by membrane evaporation and then molecular distillation to obtain a colorless and transparent product with a purity >99%. This synthetic route, utilizing a microchannel reactor, significantly increases the reaction rate and lowers the reaction temperature. It also reduces side reactions during transesterification, such as the formation of dimers and polymers from the condensation of two molecules. These polymers are not produced by the polymerization of acrylic acid double bonds, but rather by polysiloxanes formed between silicon, oxygen, and silicon. Furthermore, the purification method has been changed from distillation to thin-film evaporation and molecular distillation, transforming the intermittent purification process into a more efficient and safer continuous purification method.

[0015] Therefore, we propose a method for preparing methacryloyloxypropyltris(trimethylsiloxane)silane via a microchannel reactor to solve the problems mentioned above, such as the inability to achieve continuous production, high raw material costs, or excessive by-product acid. Summary of the Invention

[0016] The purpose of this invention is to provide a method for preparing methacryloyloxypropyltrisilane via a microchannel reactor, in order to solve the problems currently found in the market as described in the background art.

[0017] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing methacryloyloxypropyltris(trimethylsiloxane)silane via a microchannel reactor, the preparation method specifically comprising the following steps:

[0018] Step (1): The mixture A, after being thoroughly mixed with methacryloyloxypropyltrimethoxysilane (KH570) and hexamethyldisiloxane, is mixed with acidic water methanol solution B by metering pumps into a premixer and then reacted in a microchannel reactor to obtain crude methacryloyloxypropyltris(trimethylsiloxane)silane A. After separation, pH adjustment, drying and filtration, crude product A is purified by membrane evaporation and molecular distillation to obtain a colorless and transparent product with a purity >99%.

[0019] The colorless and transparent product with a purity >99% is product (I), and the byproduct of the molecular distillation purification product is byproduct (II). The structural formulas of product (I) and byproduct (II) are as follows:

[0020]

[0021] Preferably, in step (1), the acid in the acidic water methanol solution includes one of hydrogen chloride, sulfuric acid, trifluoromethanesulfonic acid, acetic acid, and p-toluenesulfonic acid.

[0022] Preferably, in step (1), the acid in the acidic water methanol solution includes multiple types of acids such as hydrogen chloride, sulfuric acid, trifluoromethanesulfonic acid, acetic acid, and p-toluenesulfonic acid.

[0023] Preferably, in step (1), the molar ratio of KH570 to hexamethyldisiloxane is 1:0.8 to 1.2. When methacryloyloxypropyltrimethoxysilane (KH570) and hexamethyldisiloxane are mixed, they can be pumped into a storage tank and stirred by a stirring blade.

[0024] Preferably, in step (1), the molar ratio of the acid-water-methanol solution is acid:water:methanol = 0.1:2:1. During the process of mixing A and acid-water-methanol solution B being pumped into the premixer by metering pumps, the metering pumps are divided into metering pump A and metering pump B. Mixture A is connected to metering pump A, and acid-water-methanol solution B is connected to metering pump B. The flow rate of metering pump A is 1000 kg / h, and the flow rate of metering pump B is 2000 kg / min.

[0025] Preferably, in step (1), the mass ratio of the mixture A to the acid-water methanol solution B is 2.8-3.2:1, and the oil temperature in the jacket of the microchannel reactor is 30°C.

[0026] Preferably, in step (1), the crude product A is separated into an acidic water-methanol solution by an oil-water separator, and the organic phase is dried and filtered after adjusting the pH with sodium carbonate to obtain crude product B.

[0027] Preferably, in step (1), the purification step of crude product B includes thin-film evaporation to remove the low boiling point, with the oil bath temperature of the thin-film evaporator being 80-90℃ and the vacuum degree being -0.1 to -0.2MPa, to obtain crude product C.

[0028] Preferably, in step (1), the crude product C purification step includes molecular distillation purification of the product. The molecular distillation oil bath temperature is 110-120℃; the vacuum degree is 0.1-0.3Pa, and the product is obtained.

[0029] Preferably, the outlet of the microchannel reactor is connected to an oil-water separator, and the oil layer is pumped into a 5m³ system via a transfer pump. 3 After adjusting the pH of the enamel-lined reactor to neutral with sodium carbonate, anhydrous magnesium sulfate was added, dried, and then filtered.

[0030] The methacryloyloxypropyltris(trimethylsiloxane)silane synthesized in this invention can be used in silicone hydrogel contact lenses, acrylic coatings, and other materials. Its CAS number is 17096-07-0. Preferably, the reaction route is as follows:

[0031]

[0032] Compared with the prior art, the beneficial effects of the present invention are: the preparation method of the methacryloyloxypropyltris(trimethylsiloxane)silane via a microchannel reactor:

[0033] 1. The microchannel reactor significantly increases the reaction rate and lowers the reaction temperature, while reducing side reactions during transesterification, such as dimers and polymers formed by the condensation of two molecules. These polymers are not produced by the polymerization of acrylic acid double bonds, but rather by polysiloxanes formed between silicon, oxygen, and silicon. Simultaneously, the purification method has been changed from the original distillation and rectification to thin-film evaporation and molecular distillation, transforming the intermittent purification method into a more efficient and safer continuous purification method.

[0034] 2. It features readily available raw materials, simple processes, easy operation, low cost, high yield, a safer production process, and high product purity. It can achieve safe and continuous ton-scale industrial production. Attached Figure Description

[0035] Figure 1 This is the chromatogram of the present invention;

[0036] Figure 2 This is the experimental peak chart of the present invention;

[0037] Figure 3 This is the NMR structure diagram of the present invention. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] Example 1

[0040] Please see Figures 1-3 This invention provides a technical solution: a method for preparing methacryloyloxypropyltris(trimethylsiloxane)silane via a microchannel reactor, the preparation method specifically including the following steps:

[0041] Step (1): The mixture A, after being thoroughly mixed with methacryloyloxypropyltrimethoxysilane (KH570) and hexamethyldisiloxane, is mixed with acidic water methanol solution B by metering pumps into a premixer and then reacted in a microchannel reactor to obtain crude methacryloyloxypropyltris(trimethylsiloxane)silane A. After separation, pH adjustment, drying and filtration, crude product A is purified by membrane evaporation and molecular distillation to obtain a colorless and transparent product with a purity >99%.

[0042] The colorless and transparent product with a purity >99% is designated as product (I), and the byproduct of molecular distillation purification is designated as byproduct (II). The structural formulas of product (I) and byproduct (II) are as follows:

[0043]

[0044] In step (1), the acid in the acidic water methanol solution includes one of hydrogen chloride, sulfuric acid, trifluoromethanesulfonic acid, acetic acid, and p-toluenesulfonic acid.

[0045] In step (1), the molar ratio of KH570 to hexamethyldisiloxane is 1:0.8 to 1.2. When methacryloyloxypropyltrimethoxysilane (KH570) and hexamethyldisiloxane are mixed, they can be pumped into the storage tank and stirred by the stirring blade.

[0046] In step (1), the molar ratio of acid water methanol solution is acid:water:methanol = 0.1:2:1. During the process of mixing A and acid water methanol solution B being pumped into the premixer by metering pumps, the metering pumps are divided into metering pump A and metering pump B. Mixture A is connected to metering pump A, and acid water methanol solution B is connected to metering pump B. The flow rate of metering pump A is 1000 kg / h, and the flow rate of metering pump B is 2000 kg / min.

[0047] In step (1), the mass ratio of mixture A to acidic water methanol solution B is 2.8-3.2:1, and the oil temperature in the jacket of the microchannel reactor is 30℃.

[0048] In step (1), crude product A is separated into acidic water and methanol solution by an oil-water separator, and the organic phase is dried and filtered after adjusting the pH with sodium carbonate to obtain crude product B.

[0049] In step (1), the purification step of crude product B includes thin-film evaporation to remove the low boiling point. The oil bath temperature of the thin-film evaporator is 80-90℃ and the vacuum degree is -0.1 to -0.2MPa, to obtain crude product C.

[0050] In step (1), the purification step of crude product C includes molecular distillation purification of the product. The molecular distillation oil bath temperature is 110-120℃; the vacuum degree is 0.1-0.3Pa, and the product is obtained.

[0051] The microchannel reactor outlet is connected to an oil-water separator, and the oil layer is pumped into a 5m³ system via a transfer pump. 3 After adjusting the pH of the enamel-lined reactor to neutral with sodium carbonate, anhydrous magnesium sulfate was added, dried, and then filtered.

[0052] Specifically, 1250 kg of KH570 (methacryloyloxypropyltrimethoxysilane) and 1750 kg of MM (hexamethyldisiloxane) were pumped into a 5 m³ / h column using a pneumatic diaphragm pump. 3 In storage vessel R-1, turn on the stirrer and stir for 10 minutes, then turn off the stirrer. Next, weigh out 10 kg of sulfuric acid, 78 kg of water, and 32 kg of methanol and add them to 1 mL of water. 3 In the enamel-lined reactor R-2, stir for 10 minutes and then let stand. Connect the storage reactor R-1 and the enamel-lined reactor R-2 to metering pumps A and B, respectively. Set the flow rate of metering pump A to 1000 kg / h and the flow rate of metering pump B to 2000 kg / min. Set the oil temperature in the microchannel reactor jacket to 30℃. When the internal temperature of the microchannel reactor reaches 30℃, simultaneously turn on metering pumps A and B to start the reaction. Connect the outlet of the microchannel reactor to an oil-water separator, and pump the oil layer into a 5m³ tank via a transfer pump. 3 After adjusting the pH to neutral with sodium carbonate in an enamel-lined reactor, anhydrous magnesium sulfate was added, and the mixture was dried and filtered. Crude product B was then transferred to storage tank A. A thin-film evaporator was set at an oil temperature of 80℃ and a vacuum of -0.1 to -0.2 MPa to separate excess MM and methanol, yielding crude product C. This crude product C was directly fed into molecular distillation via a gear pump for product separation and purification from high-boiling-point substances. The molecular distillation oil bath was set at 120℃, and the vacuum was 2–10 Pa. 3940 kg of a colorless, transparent product with a purity of 99% was obtained, representing a yield of 93%. The reaction equation is as follows:

[0053]

[0054] Example 2

[0055] Please see Figures 1-3 This invention provides a technical solution: a method for preparing methacryloyloxypropyltris(trimethylsiloxane)silane via a microchannel reactor. The difference between this embodiment and Embodiment 1 is that:

[0056] In step (1), the acids in the acidic water methanol solution include hydrogen chloride, sulfuric acid, trifluoromethanesulfonic acid, acetic acid, and p-toluenesulfonic acid.

[0057] 1000 kg KH570 (methacryloyloxypropyltrimethoxysilane) and 1500 kg MM (hexamethyldisiloxane) were pumped into a 5 m³ / h column using a pneumatic diaphragm pump. 3 In storage vessel R-1, turn on the stirrer and stir for 10 minutes, then turn off the stirrer. Next, weigh out 12 kg of sulfuric acid, 80 kg of water, and 34 kg of methanol and add them to 1 mL of water. 3 In the enamel-lined reactor R-2, stir for 10 minutes and then let stand. Connect the storage reactor R-1 and the enamel-lined reactor R-2 to metering pumps A and B, respectively. Set the flow rate of metering pump A to 1000 kg / h and the flow rate of metering pump B to 2000 kg / min. Set the oil temperature in the microchannel reactor jacket to 30℃. When the internal temperature of the microchannel reactor reaches 30℃, simultaneously turn on metering pumps A and B to start the reaction. Connect the outlet of the microchannel reactor to an oil-water separator, and pump the oil layer into a 5m³ tank via a transfer pump. 3 After adjusting the pH to neutral with sodium carbonate in the enamel-lined reactor, anhydrous magnesium sulfate was added, and the mixture was dried and filtered. Crude product B was then transferred to storage tank A. A thin-film evaporator was set at an oil temperature of 90°C and a vacuum of -0.1 to -0.2 MPa to separate excess MM and methanol, yielding crude product C. This crude product C was directly fed into molecular distillation via a gear pump for product separation and purification from high-boiling-point substances. The molecular distillation oil bath was set at 110°C, and the vacuum was 2–10 Pa, yielding a colorless and transparent product with a purity of 99% and a yield of 93%.

[0058] Example 3

[0059] This invention provides a technical solution: a method for preparing methacryloyloxypropyltris(trimethylsiloxane)silane via a microchannel reactor. The difference between this embodiment and Embodiment 1 is as follows:

[0060] 1120 kg KH570 (methacryloyloxypropyltrimethoxysilane) and 1620 kg MM (hexamethyldisiloxane) were pumped into a 5 m³ / h column using a pneumatic diaphragm pump. 3 In storage vessel R-1, turn on the stirrer and stir for 10 minutes, then turn off the stirrer. Next, weigh out 15 kg of sulfuric acid, 85 kg of water, and 36 kg of methanol and add them to 1 mL of water. 3In the enamel-lined reactor R-2, stir for 10 minutes and then let stand. Connect the storage reactor R-1 and the enamel-lined reactor R-2 to metering pumps A and B, respectively. Set the flow rate of metering pump A to 1000 kg / h and the flow rate of metering pump B to 2000 kg / min. Set the oil temperature in the microchannel reactor jacket to 30℃. When the internal temperature of the microchannel reactor reaches 30℃, simultaneously turn on metering pumps A and B to start the reaction. Connect the outlet of the microchannel reactor to an oil-water separator, and pump the oil layer into a 5m³ tank via a transfer pump. 3 After adjusting the pH to neutral with sodium carbonate in the enamel-lined reactor, anhydrous magnesium sulfate was added, and the mixture was dried and filtered. Crude product B was then transferred to storage tank A. A thin-film evaporator was set at an oil temperature of 85°C and a vacuum of -0.1 to -0.2 MPa to separate excess MM and methanol, yielding crude product C. This crude product C was directly fed into molecular distillation via a gear pump for product separation and purification from high-boiling-point substances. The molecular distillation oil bath was set at 115°C, and the vacuum was 2–10 Pa, yielding a colorless and transparent product with a purity of 99% and a yield of 93%.

[0061] The contents not described in detail in this specification are existing technologies known to those skilled in the art.

[0062] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing methacryloyloxypropyltris(trimethylsiloxane)silane via a microchannel reactor, characterized in that: The preparation method specifically includes the following steps: Step (1): The mixture A, after being thoroughly mixed with methacryloyloxypropyltrimethoxysilane (KH570) and hexamethyldisiloxane, is mixed with acidic water methanol solution B by metering pumps into a premixer and then reacted in a microchannel reactor to obtain crude methacryloyloxypropyltris(trimethylsiloxane)silane A. After separation, pH adjustment, drying and filtration, crude product A is purified by membrane evaporation and molecular distillation to obtain a colorless and transparent product with a purity >99%. The colorless and transparent product with a purity >99% is product (I), and the byproduct of the molecular distillation purification product is byproduct (II). The structural formulas of product (I) and byproduct (II) are as follows:

2. The method for preparing methacryloyloxypropyltris(trimethylsiloxane)silane via a microchannel reactor according to claim 1, characterized in that: In step (1), the acid in the acidic water methanol solution includes one of hydrogen chloride, sulfuric acid, trifluoromethanesulfonic acid, acetic acid, and p-toluenesulfonic acid.

3. The method for preparing methacryloyloxypropyltris(trimethylsiloxane)silane via a microchannel reactor according to claim 1, characterized in that: In step (1), the acid in the acidic water methanol solution includes multiple types of acids such as hydrogen chloride, sulfuric acid, trifluoromethanesulfonic acid, acetic acid, and p-toluenesulfonic acid.

4. The method for preparing methacryloyloxypropyltris(trimethylsiloxane)silane via a microchannel reactor according to claim 1, characterized in that: In step (1), the molar ratio of KH570 to hexamethyldisiloxane is 1:0.8 to 1.

2. When methacryloyloxypropyltrimethoxysilane (KH570) and hexamethyldisiloxane are mixed, they can be pumped into a storage vessel and stirred by a stirring blade.

5. The method for preparing methacryloyloxypropyltris(trimethylsiloxane)silane via a microchannel reactor according to claim 1, characterized in that: In step (1), the molar ratio of the acid-water-methanol solution is: acid: Water:methanol = 0.1:2:

1. During the process of mixing A and acidic water methanol solution B being pumped into the premixer by metering pumps, the metering pumps are divided into metering pump A and metering pump B. Mixture A is connected to metering pump A, and acidic water methanol solution B is connected to metering pump B. The flow rate of metering pump A is 1000 kg / h, and the flow rate of metering pump B is 2000 kg / min.

6. The method for preparing methacryloyloxypropyltris(trimethylsiloxane)silane via a microchannel reactor according to claim 1, characterized in that: In step (1), the mass ratio of mixture A to acidic water methanol solution B is 2.8-3.2:1, and the oil temperature in the jacket of the microchannel reactor is 30℃.

7. The method for preparing methacryloyloxypropyltris(trimethylsiloxane)silane via a microchannel reactor according to claim 1, characterized in that: In step (1), crude product A is separated into acidic water and methanol solution by an oil-water separator, and the organic phase is dried and filtered after adjusting the pH with sodium carbonate to obtain crude product B.

8. The method for preparing methacryloyloxypropyltris(trimethylsiloxane)silane via a microchannel reactor according to claim 1, characterized in that: In step (1), the purification step of crude product B includes thin-film evaporation to remove the low boiling point. The oil bath temperature of the thin-film evaporator is 80-90℃ and the vacuum degree is -0.1 to -0.2MPa, to obtain crude product C.

9. The method for preparing methacryloyloxypropyltris(trimethylsiloxane)silane via a microchannel reactor according to claim 1, characterized in that: In step (1), the crude product C purification step includes molecular distillation purification of the product. The molecular distillation oil bath temperature is 110-120℃; the vacuum degree is 0.1-0.3Pa, and the product is obtained.

10. The method for preparing methacryloyloxypropyltris(trimethylsiloxane)silane via a microchannel reactor according to claim 1, characterized in that: The outlet of the microchannel reactor is connected to an oil-water separator, and the oil layer is pumped into a 5m³ flow meter via a transfer pump. 3 After adjusting the pH of the enamel-lined reactor to neutral with sodium carbonate, anhydrous magnesium sulfate was added, dried, and then filtered.

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