Preparation method of (3-methacryloxy-2-hydroxypropoxy) propyl bis (trimethylsiloxy) methylsilane

Abstract

The invention relates to the technical field of organic synthesis, and discloses a preparation method of (3-methacryloxy-2-hydroxypropoxy) propyl bis (trimethylsiloxy) methylsilane, which comprises the following steps: mixing allyl glycidyl ether, a platinum catalyst and heptamethyltrisiloxane, passing through a microchannel reactor, and rectifying to obtain an intermediate A; mixing the intermediate A, methacrylic acid, THF and a catalyst, and reacting through a micro-channel reactor to obtain a crude product; and concentrating, filtering and rectifying the crude product to obtain the product. The preparation method of 3-methylacryloyloxy-2-hydroxypropoxy) propyl bis (trimethylsiloxy) methylsilane has the advantages of easily available raw materials, simple process, simple operation, low cost and high yield, and through a two-step microchannel reactor reaction process, the reaction time is greatly shortened, the reaction temperature is reduced, side reaction products are reduced, the purity of the final product is improved, and the preparation method is suitable for industrial production. Meanwhile, the reaction risk is greatly reduced, and a safer production process is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of organic synthesis, in particular to a method for preparing (3-methacryloyloxy-2-hydroxypropoxy)propylbis(trimethylsilyloxy)methylsilane. Background Art

[0002] The oxygen permeability of contact lenses is a very important indicator for measuring the wearing comfort of lenses, and the introduction of silicon materials has become a breakthrough point for improving the oxygen permeability coefficient. (3-methacryloyloxy-2-hydroxypropoxy)propylbis(trimethylsiloxy)methylsilane is one of the important monomers for preparing high-performance contact lenses.

[0003] The existing synthesis method of (3-methacryloyloxy-2-hydroxypropoxy)propylbis(trimethylsilyloxy)methylsilane is as follows:

[0004]

[0005] The above method uses methacrylic acid and epoxy ring opening to obtain the product in one step. This method will generate (isomer II), disubstituted (impurity III) and (impurity IV) during epoxy ring opening:

[0006]

[0007] Similarly, the method reported in US2004 / 0267039 is similar and still has the same problem. US2008 / 0119627 using the same method clearly states that the obtained product is a mixture of the target product and the above-mentioned isomer II.

[0008] The synthetic route of (3-methacryloyloxy-2-hydroxypropoxy)propylbis(trimethylsilyloxy)methylsilane disclosed in US2006 / 47134 is as follows:

[0009]

[0010] This method obtains the final product through a two-step process. By changing the reaction order, the by-product generation in the epoxy bond ring-opening esterification stage is reduced. However, the presence of two double bonds in the final hydrosilylation also leads to the generation of a large amount of isomer V:

[0011]

[0012] In summary, the main problem of the existing synthesis technology of (3-methacryloyloxy-2-hydroxypropoxy)propylbis(trimethylsiloxy)methylsilane is that there are multiple reaction sites in a single-step reaction, resulting in a large proportion of isomers produced in the reaction and low purity. When the first addition reaction is carried out by a conventional reactor, the epoxy bond of allyl glycidyl ether has the risk of ring-opening polymerization. If the addition reaction of heptamethyltrisiloxane with allyl glycidyl ether is not completed in time in the presence of a platinum catalyst, there is a risk of dehydrogenation to produce hydrogen. Both are extremely dangerous side reactions in chemical production. At the same time, (3-methacryloyloxy-2-hydroxypropoxy)propylbis(trimethylsiloxy)methylsilane and the raw material methacrylic acid are both easily polymerized compounds. When reacted by a conventional conventional reactor, the ring-opening reaction time of methacrylic acid and epoxy is long, which increases the polymerization risk of raw materials and products.

[0013] In view of this, we conducted in-depth research on the above issues and proposed this case to solve the above problems. Summary of the invention

[0014] The object of the present invention is to provide a method for preparing (3-methacryloyloxy-2-hydroxypropoxy)propylbis(trimethylsiloxy)methylsilane, so as to solve the problems of low purity and low yield of side reaction products in the existing method for preparing 3-methacryloyloxy-2-hydroxypropoxy)propylbis(trimethylsiloxy)methylsilane proposed in the above background technology.

[0015] To achieve the above object, the present invention provides the following technical solution: a method for preparing (3-methacryloyloxy-2-hydroxypropoxy)propylbis(trimethylsilyloxy)methylsilane, comprising the following steps:

[0016] Step 1: pumping allyl glycidyl ether, platinum catalyst and heptamethyltrisiloxane into a premixer through a metering pump for mixing;

[0017] Step 2: subjecting the mixture obtained in step 1 to a hydrosilylation reaction through a microchannel reactor to obtain glycidyl heptamethyl trisiloxane;

[0018] Step 3: distilling the obtained epoxypropyl heptamethyltrisiloxane to obtain an intermediate A with a purity of >98%;

[0019] Step 4: The intermediate A, methacrylic acid, THF and the catalyst are pumped into a premixer through a metering pump for mixing;

[0020] Step 5: reacting the mixture obtained in step 4 through a microchannel reactor to obtain a crude product;

[0021] Step 6: The crude product is concentrated, filtered and distilled to obtain a product with a purity of >97%.

[0022] As a preferred technical solution of the present invention, the platinum catalyst in step 1 is one or more of chloroplatinic acid THF solution, chloroplatinic acid IPA solution, Custer toluene solution, and Custer dimethyl silicone oil solution.

[0023] As a preferred technical solution of the present invention, in the step 1, the molar ratio of allyl glycidyl ether, platinum catalyst and heptamethyltrisiloxane is 1:0.001-0.005:0.8-1.0.

[0024] As a preferred technical solution of the present invention, in the step 2, the liquid holding capacity of the microchannel reactor is 100 mL, the retention time of the mixture in the reactor is 3 min, and the reaction temperature is 80°C.

[0025] As a preferred technical solution of the present invention, in step three, a distillation tower is used for distillation, the top temperature of the distillation tower is 110 to 120° C., and the vacuum degree is -0.1 to -0.2 MPa.

[0026] As a preferred technical solution of the present invention, the catalyst in step 4 is one or more of trifluoroethyl ether boric acid, potassium methacrylate, and organosilicon-modified metal catalyst (self-made).

[0027] As a preferred technical solution of the present invention, the molar ratio of intermediate A, methacrylic acid and THF in step 4 is 1:1.05-1.5:2-5.

[0028] As a preferred technical solution of the present invention, in the step 5, the liquid holding capacity of the microchannel reactor is 100 mL, the retention time of the mixture in the reactor is 5 min, and the reaction temperature is 80°C.

[0029] As a preferred technical solution of the present invention, in step six, a distillation tower is used for distillation, the top temperature of the distillation tower is 80-90° C., and the vacuum degree is 0.1-0.3 MPa.

[0030] Compared with the prior art, the invention has the following beneficial effects: the preparation method of 3-methacryloyloxy-2-hydroxypropoxy)propylbis(trimethylsiloxy)methylsilane has readily available raw materials, simple process, simple operation, low cost and high yield; through a two-step microchannel reactor reaction process, the reaction risk caused by the epoxy ring opening of allyl glycidyl ether in the reaction process and the risk caused by the dehydrogenation of heptamethyltrisiloxane to generate hydrogen in the presence of a platinum catalyst after a large amount of aggregation of heptamethyltrisiloxane can be avoided, and the polymerization risk of methacrylic acid and the product in the reaction process is avoided; at the same time, the microchannel reaction has high reaction efficiency, greatly reduces the reaction time, reduces the reaction temperature, reduces the side reaction products, improves the purity of the final product, and at the same time greatly reduces the reaction risk, ensures a safer production process, thereby realizing continuous large-scale production of (3-methacryloyloxy-2-hydroxypropoxy)propylbis(trimethylsiloxy)methylsilane. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 GC chart of intermediate A prepared in the present invention;

[0032] Figure 2 GC chart of the product prepared by the present invention;

[0033] Figure 3 This is the NMR image of the product prepared by the present invention. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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.

[0035] The technical solution of the present invention is a method for preparing (3-methacryloyloxy-2-hydroxypropoxy)propylbis(trimethylsilyloxy)methylsilane, comprising the following steps:

[0036] Step 1: injecting allyl glycidyl ether, platinum catalyst and heptamethyl trisiloxane into a premixer at a molar ratio of 1:0.001-0.005:0.8-1.0 through a metering pump for mixing, wherein the platinum catalyst is one or more of chloroplatinic acid THF solution, chloroplatinic acid IPA solution, Custer toluene solution and Custer dimethyl silicone oil solution;

[0037] Step 2: subjecting the mixture obtained in step 1 to a hydrosilylation reaction through a microchannel reactor, controlling the retention time of the mixture in the reactor to be 3 minutes and the reaction temperature to be 80° C., to obtain glycidyl heptamethyl trisiloxane;

[0038] Step 3: distill the obtained epoxypropyl heptamethyl trisiloxane in a distillation tower, control the top temperature of the distillation tower to 110-120° C., and the vacuum degree to -0.1-0.2 MPa, to obtain an intermediate A with a purity of >98%;

[0039] Step 4: intermediate A, methacrylic acid, THF and a catalyst are pumped into a premixer through a metering pump for mixing, wherein the molar ratio of intermediate A, methacrylic acid and THF is controlled to be 1:1.05-1.5:2-5, and the catalyst is one or more of trifluoroethyl ether boric acid, potassium methacrylate and organosilicon-modified metal catalyst (self-made);

[0040] Step 5: reacting the mixture obtained in step 4 through a microchannel reactor to obtain a crude product, wherein the retention time of the mixture in the reactor is 5 minutes and the reaction temperature is 80° C.;

[0041] Step 6: The obtained crude product is concentrated, filtered and distilled, and the top temperature of the distillation tower is controlled to be 80-90° C. and the vacuum degree is 0.1-0.3 MPa to obtain a product with a purity of >97%.

[0042] Embodiment 1

[0043] Weigh 2870g of heptamethyltrisiloxane in feed barrel A, then weigh 1770g of allyl glycidyl ether and 3mL of platinum catalyst and mix them evenly in feed barrel B, connect feed barrels A and B to metering pumps A and B respectively, set the flow rate of metering pump A to 21.85mL / min, the flow rate of metering pump B to 11.49mL / min, set the jacket oil temperature of the microchannel reactor to 80°C, and when the temperature in the microchannel reactor reaches 80°C, open metering pumps A and B at the same time to start the reaction, connect the outlet of the microchannel reactor to a thin film evaporator, set the oil temperature of the thin film evaporator to 80°C, and the vacuum degree is -0.1 to -0.2Mpa, separate excess allyl glycidyl ether and crude intermediate product A, analyze the intermediate product purity to be 95%, and do not contain 2% isomers such as isomer formula (I), and distill the crude product in a distillation tower to obtain an intermediate product A with a purity of 98% and a yield of 90%. The reaction route is as follows:

[0044]

[0045] Weigh 3018g of intermediate A epoxypropyl heptamethyl trisiloxane into feed barrel A, then weigh 920g of methacrylic acid and 4g of organosilicon-modified metal catalyst (homemade) THF solution 2080g and inhibitor and mix them evenly into feed barrel B, connect feed barrels A and B to metering pumps A and B respectively, set the flow rate of metering pump A to 10.00mL / min, the flow rate of metering pump B to 10.00mL / min, set the jacket oil temperature of the microchannel reactor to 80°C, when the temperature inside the microchannel reactor reaches 80°C, open metering pumps A and B at the same time to start the reaction, connect the outlet of the microchannel reactor to a thin film evaporator, set the oil temperature of the thin film evaporator to 40°C, and the vacuum degree to 0.1 to 0.3Mpa, separate excess methacrylic acid and THF, analyze the purity of the crude product to be 95%, and distill the crude product in a distillation tower to obtain a product with a purity of 98% and a yield of 90%. The reaction route is as follows:

[0046]

[0047] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in the field. Although the embodiments of the present invention have been shown and described, it is understood by ordinary technicians in the field that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for preparing (3-methacryloyloxy-2-hydroxypropoxy)propylbis(trimethylsilyloxy)methylsilane, characterized in that: The following steps are involved: Step 1: pumping allyl glycidyl ether, platinum catalyst and heptamethyltrisiloxane into a premixer through a metering pump for mixing; Step 2: subjecting the mixture obtained in step 1 to a hydrosilylation reaction through a microchannel reactor to obtain glycidyl heptamethyl trisiloxane; Step 3: distilling the obtained epoxypropyl heptamethyltrisiloxane to obtain an intermediate A with a purity of >98%; Step 4: The intermediate A, methacrylic acid, THF and the catalyst are pumped into a premixer through a metering pump for mixing; Step 5: reacting the mixture obtained in step 4 through a microchannel reactor to obtain a crude product; Step 6: The crude product is concentrated, filtered and distilled to obtain a product with a purity of >97%.

2. The method for preparing (3-methacryloyloxy-2-hydroxypropoxy)propylbis(trimethylsilyloxy)methylsilane according to claim 1, characterized in that: The platinum catalyst in step 1 is one or more of chloroplatinic acid THF solution, chloroplatinic acid IPA solution, Custer toluene solution, and Custer dimethyl silicone oil solution.

3. The method for preparing (3-methacryloyloxy-2-hydroxypropoxy)propylbis(trimethylsilyloxy)methylsilane according to claim 1, characterized in that: In the step 1, the molar ratio of allyl glycidyl ether, platinum catalyst and heptamethyltrisiloxane is 1:0.001-0.005:0.8-1.

0.

4. The method for preparing (3-methacryloyloxy-2-hydroxypropoxy)propylbis(trimethylsilyloxy)methylsilane according to claim 1, characterized in that: In the step 2, the liquid holding capacity of the microchannel reactor is 100 mL, the retention time of the mixture in the reactor is 3 min, and the reaction temperature is 80° C.

5. The method for preparing (3-methacryloyloxy-2-hydroxypropoxy)propylbis(trimethylsilyloxy)methylsilane according to claim 1, characterized in that: In the step 3, a distillation tower is used for distillation, the top temperature of the distillation tower is 110 to 120° C., and the vacuum degree is -0.1 to -0.2 MPa.

6. The method for preparing (3-methacryloyloxy-2-hydroxypropoxy)propylbis(trimethylsilyloxy)methylsilane according to claim 1, characterized in that: The catalyst in step 4 is one or more of trifluoroethyl ether boric acid, potassium methacrylate, and organosilicon-modified metal catalyst (self-made).

7. The method for preparing (3-methacryloyloxy-2-hydroxypropoxy)propylbis(trimethylsilyloxy)methylsilane according to claim 1, characterized in that: In the step 4, the molar ratio of intermediate A, methacrylic acid and THF is 1:1.05-1.5:2-5.

8. The method for preparing (3-methacryloyloxy-2-hydroxypropoxy)propylbis(trimethylsilyloxy)methylsilane according to claim 1, characterized in that: In the step 5, the liquid holding capacity of the microchannel reactor is 100 mL, the retention time of the mixture in the reactor is 5 min, and the reaction temperature is 80° C.

9. The method for preparing (3-methacryloyloxy-2-hydroxypropoxy)propylbis(trimethylsilyloxy)methylsilane according to claim 1, characterized in that: In the step six, a distillation tower is used for distillation, the top temperature of the distillation tower is 80-90° C., and the vacuum degree is 0.1-0.3 MPa.

10. The method for preparing (3-methacryloyloxy-2-hydroxypropoxy)propylbis(trimethylsilyloxy)methylsilane according to claim 1, characterized in that: The intermediate A obtained in step 3 has the structural formula: The product structure obtained in step six is:

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