Preparation method of phenethyl trialkoxysilane

Abstract

The invention relates to a preparation method of phenethyl trialkoxysilane, and belongs to the technical field of synthesis of fine chemicals. The method comprises the following steps: adding styrene and a catalyst into a reaction kettle; dropwise adding trialkoxysilane into the reaction kettle, wherein the molar ratio of styrene to trialkoxysilane is (1.8-1.0): 1.0; and rectifying the reaction material to obtain a target product. The phenethyl trialkoxysilane with the purity larger than 98% and the mass yield higher than 85% (with the mol feeding amount of trialkoxysilane as the standard) is generated through the reaction of styrene and trialkoxysilane under the solvent-free condition, and compared with a large amount of hydrogen chloride as a byproduct in the prior art, the phenethyl trialkoxysilane synthesis method is environmentally friendly, small in corrosion to equipment and low in production cost. The method can prolong the service life of equipment, does not need to use a solvent, further reduces the production cost, has fewer byproducts, does not generate waste materials, is high in raw material conversion rate, and can be used for industrial production.

Description

Technical Field

[0001] The invention relates to the technical field of synthesis of fine chemicals, and in particular to a method for preparing phenethyltrialkoxysilane. Background Art

[0002] Phenylethyltrialkoxysilane is an important silane coupling agent, mainly used as a crosslinker for silicone resins, a raw material for phenyl silicone oil, a raw material for preparing high molecular organic compounds, a surface treatment agent, an additive for waterproof coatings, and electronic materials. In optoelectronic displays, LED packaging, and solar panels, it can enhance the insulation and corrosion resistance of materials and form an insulating film, thereby effectively preventing current leakage and interference and ensuring the normal operation of electronic equipment.

[0003] The conventional method for preparing phenethyltrialkoxysilane is to use chlorosilane monomer (hydrogen-containing chlorosilane) and styrene as raw materials, synthesize phenethylchlorosilane through a silylation reaction, and then obtain phenethyltrialkoxysilane through alcoholysis in a solvent. Since the alcoholysis reaction will produce a large amount of hydrogen chloride, if the hydrogen chloride cannot be discharged from the system in time, it is easy to cause alcoholysis to have side reactions, resulting in a decrease in product yield. The use of solvents also increases production energy consumption. At the same time, the strong acidity of hydrogen chloride is easy to corrode equipment, and this process has high requirements for equipment conditions. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing phenethyltrialkoxysilane, which solves the problems of high production energy consumption and easy corrosion of equipment by hydrogen chloride produced by the reaction in the existing production technology. The method of the present invention can improve the product yield, does not produce hydrogen chloride gas, can extend the service life of the equipment, and does not require the use of solvents.

[0005] The above-mentioned object of the present invention is achieved by the following technical solutions: A method for preparing phenethyltrialkoxysilane comprises the following steps: A. Add styrene and catalyst into the reactor, and keep warm for activation under stirring; B. adding trialkoxysilane dropwise to the reaction kettle, and keeping the temperature to react after the addition is completed to obtain a reacted material, wherein the molar ratio of styrene to trialkoxysilane is 1.8-1.0:1.0; C. The materials after the reaction are subjected to distillation treatment to obtain the finished product of phenethyltrialkoxysilane.

[0006] Furthermore, the platinum catalyst is one of the platinum homogeneous catalysts: Speier catalyst; Karstedt catalyst; Pt-acetylacetone complex catalyst; Pt-PPh3 complex catalyst. Preferably, it is a Pt-PPh3 complex catalyst.

[0007] The use of Speier catalyst in the process of the invention is generally understood by those skilled in the art to be hexachloroplatinic acid or hexachloroplatinic acid dissolved in isopropanol, other solvents for this catalytic system being known to those skilled in the art, such as acetone or methanol or solvent mixtures.

[0008] Karstedt's catalyst is a soluble Pt(0) complex catalyst, which is a complex catalyst formed in the form of a concentrate of chloroplatinic acid and divinyltetramethyldisiloxane.

[0009] The Pt-acetylacetone complex catalyst is a complex catalyst composed of 1 gram of chloroplatinic acid and 3ML of acetylacetone in the Speier catalyst.

[0010] The Pt-PPh3 complex catalyst is a complex catalyst prepared by combining 1 gram of chloroplatinic acid in the Speier catalyst with 2 grams of triphenylphosphine, and is preferably a hydrosilylation catalyst in the preparation of phenethyltrialkoxysilane.

[0011] Furthermore, the amount of the catalyst used (calculated based on the mass of the metal platinum contained therein) is 3 / 1000000 to 2 / 100000, preferably 3 to 8 / 1000000 of the mass of the reaction material.

[0012] Furthermore, the temperature of the heat preservation activation is 60-110°C, preferably 85-90°C.

[0013] In step A, the activation time of heat preservation is 30 to 60 minutes, preferably 40 to 50 minutes.

[0014] In step B, the dripping time of trimethoxysilane is 40 to 120 min, preferably 60 to 90 min.

[0015] In step B, the reaction temperature of the dropwise addition of trimethoxysilane should be controlled at 60-120°C, preferably 90-110°C.

[0016] In step B, the heat preservation reaction time is 1 to 4 hours, preferably 1 to 2 hours.

[0017] In step C, the vacuum degree of vacuum distillation is 0.098 MPa, and the fraction with a temperature of 100-140°C at the top of the distillation tower is collected as the finished product. The preferred temperature is 100-140°C.

[0018] Furthermore, based on the mol amount of the trialkoxysilane fed, the mass yield of the phenethyltrialkoxysilane product prepared by the method of the present invention is higher than 85%.

[0019] Furthermore, the reaction mechanism of the preparation method of the present invention is: CH2=CHC6H5 +HSi(OR)3→C6H5CH2CH2Si(OR)3 Or CH2=CHC6H5 +HSiR'(OR)2→C6H5CH2CH2SiR'(OR)2 Wherein R = alkyl, such as methyl, ethyl or propyl. R' = methyl. When R is equal to methyl, phenethyl trimethoxy silane and phenethyl methyl dimethoxy silane are obtained; when R is equal to ethyl, phenethyl triethoxy silane is obtained.

[0020] The beneficial effects of the present invention are: 1. The preparation method provided by the present invention is to generate phenethyltrialkoxysilane with a purity greater than 98% and a mol mass yield greater than 85% (based on the mol feed amount of trialkoxysilane) by reacting styrene and trimethoxysilane under solvent-free conditions. Compared with the prior art that produces a large amount of hydrogen chloride as a by-product, the present invention is more environmentally friendly and less corrosive to equipment, and can extend the service life of the equipment. No solvent is required, thereby reducing production costs, and there are fewer by-products, no waste is generated, and the raw material conversion rate is high, which can be used for industrial production.

[0021] 2. The preparation method provided by the present invention uses raw materials that are easily available and relatively safe. The reaction is carried out at a temperature not higher than 120°C, and the amount of catalyst used is extremely small, which greatly reduces the production cost and ensures process safety. It is highly practical. DETAILED DESCRIPTION

[0022] 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, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention. In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below in conjunction with specific embodiments.

[0023] A method for preparing phenethyltrialkoxysilane of the present invention has the following reaction mechanism: CH2=CHC6H5 +HSi(OR)3→C6H5CH2CH2Si(OR)3 Or CH2=CHC6H5 +HSiR'(OR)2→C6H5CH2CH2SiR'(OR)2 Wherein R = alkyl, such as methyl, ethyl or propyl. R' = methyl. When R is equal to methyl, phenethyl trimethoxysilane and phenethyl methyl dimethoxysilane are obtained; when R is equal to ethyl, phenethyl triethoxysilane is obtained.

[0024] The preparation method comprises the following steps: A. Add styrene and catalyst into the reactor and activate them under stirring.

[0025] B. Add trialkoxysilane dropwise to the reaction kettle, control the reaction temperature, and keep the temperature for reaction after the addition is completed to obtain a reaction material, wherein the molar ratio of styrene to trialkoxysilane is 1.8-1.0:1.0; C. Distill the materials after the reaction to obtain the target product, phenethyltrialkoxysilane.

[0026] Specifically, the catalyst is a platinum homogeneous catalyst Pt-PPh3 complex catalyst, and the amount of the catalyst used (calculated based on the mass of metal platinum contained therein) is 3 / 1000000~2 / 100000, preferably 3~8 / 1000000 of the mass of the reaction material.

[0027] In step A, the temperature of the heat preservation activation is 60-110° C., and the time of the heat preservation activation is 30-60 min.

[0028] In step B, when trialkoxysilane is added dropwise to the reaction kettle, the addition time is 40-120 min, the reaction temperature is controlled to be stable at 60-120° C., and the heat preservation reaction time is 1-4 h.

[0029] In step C, the vacuum degree of the vacuum distillation is 0.098 MPa, and the temperature of the cut fraction is 100-140° C. The temperature of the cut fraction is the finished product.

[0030] The invention generates phenethyltrialkoxysilane with a purity greater than 98% and a mass yield greater than 85% (based on the mol feeding amount of trialkoxysilane) by reacting styrene and trialkoxysilane under solvent-free conditions. Compared with the prior art in which a large amount of hydrogen chloride is produced as a by-product, the invention is more environmentally friendly and less corrosive to equipment, and can extend the service life of the equipment. No solvent is required, thereby reducing production costs. Furthermore, less by-products are produced, no waste is generated, and the raw material conversion rate is high, so the invention can be used for industrial production.

[0031] The present invention is further described in detail below with reference to the embodiments. Embodiment 1:

[0032] In a four-necked flask equipped with a stirrer, a constant pressure dropping funnel, a reflux condenser and a thermometer, nitrogen was introduced into the flask until the flask was full. Then, 11.48 g (0.11 mol) of 99.8% styrene and a Pt-PPh3 complex catalyst containing 5 PPM of platinum were added. Stirring was started and the temperature was raised to 85-90°C to activate the catalyst for 50 minutes.

[0033] Weigh 12.47g (0.1 mol) of trimethoxysilane (content 98%) and put it into a dropping funnel. After the catalyst is activated, add trimethoxysilane to the four-necked bottle at a rate of 1h. Control the reaction temperature to be stable at 90~110℃. After the addition is completed, continue to maintain the temperature for 1.5h and take samples for analysis.

[0034] Gas chromatography analysis showed that the content of trimethoxysilane in the material was 0.5%; the content of tetramethoxysilane was 1%; the content of styrene was 5%; the content of phenethyltrimethoxysilane was 90%, and the reaction yield was 95%.

[0035] The reaction material was subjected to vacuum distillation (-0.098 MPa, collecting fractions at a temperature of 100-130°C), and 20.46 g of distilled product with a content of 98% was obtained, with a mol yield of 88.62%. Embodiment 2:

[0036] In a four-necked flask equipped with a stirrer, a constant pressure dropping funnel, a reflux condenser and a thermometer, nitrogen was introduced into the flask until the flask was full, and then 11.48 g (0.11 mol) of 99.8% styrene and a Pt-PPh3 complex catalyst containing 5 PPM of platinum were added. Stirring was started and the temperature was raised to 85-90°C to activate the catalyst for 40 minutes.

[0037] Weigh 16.76g (0.1 mol) of triethoxysilane (content 98%) and put it into a dropping funnel. After the catalyst is activated, add triethoxysilane to the four-necked bottle at a constant rate of 1.5h. Control the reaction temperature to be stable at 95~120℃. After the addition is completed, continue to maintain it for 2h and take samples for analysis. The crude product reaction yield is 97.31%.

[0038] The reaction material was subjected to vacuum distillation (-0.098 MPa, collecting fractions at 115-140°C), and 23.08 g of distilled product with a content of 98% was obtained, with a mol yield of 86%. Embodiment 3:

[0039] In a four-necked flask equipped with a stirrer, a constant pressure dropping funnel, a reflux condenser and a thermometer, nitrogen was introduced into the flask until the flask was full, and then 11.48 g (0.11 mol) of 99.8% styrene and a Pt-PPh3 complex catalyst containing 10 PPM of platinum were added, stirring was started, and the temperature was raised to 85-90°C to activate the catalyst for 60 minutes.

[0040] Weigh 10.84g (0.1mol) of methyldimethoxysilane (content 98%, can be purchased or synthesized in the laboratory) and put it into a dropping funnel; after the catalyst is activated, add methyldimethoxysilane to the four-necked bottle, and control the speed to drip evenly for 1.5h. Control the reaction temperature between 90~105℃, and continue to maintain it for 1h after the dripping is completed. Take samples for analysis. The crude product reaction yield is 95.85%.

[0041] The reaction material was subjected to vacuum distillation (-0.098 MPa, collecting fractions at a temperature of 100-115°C), and 19.10 g of distilled product with a content of 98% was obtained, with a mol yield of 89.51%.

[0042] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made to the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing phenethyltrialkoxysilane, characterized in that: The steps include: A. Add styrene and catalyst into the reactor, and keep warm for activation under stirring; B. adding trialkoxysilane dropwise to the reaction kettle, and keeping the temperature to react after the addition is completed to obtain a reaction material, wherein the molar ratio of styrene to trialkoxysilane is 1.8-1.0:1.0; C. The materials after the reaction are subjected to distillation treatment to obtain the finished product of phenethyltrialkoxysilane.

2. The method for preparing phenethyltrialkoxysilane according to claim 1, characterized in that: The catalyst is a platinum homogeneous catalyst: Speier catalyst; Karstedt catalyst; Pt-acetylacetone complex catalyst; Pt-PPh3 complex catalyst.

3. The method for preparing phenethyltrialkoxysilane according to claim 2, characterized in that: The amount of the catalyst used, calculated based on the mass of the metal platinum contained therein, is 3 / 1000000 to 2 / 100000 of the mass of the reaction material.

4. The method for preparing phenethyltrialkoxysilane according to claim 1, characterized in that: In step A, the temperature of heat preservation and activation is 60-110° C., and the time is 30-60 min.

5. The method for preparing phenethyltrialkoxysilane according to claim 1, characterized in that: In step B, the trialkoxysilane is added dropwise for 40 to 120 minutes at a temperature of 60 to 120°C.

6. The method for preparing phenethyltrialkoxysilane according to claim 1, characterized in that: In step B, the heat preservation reaction time is 1 to 4 hours.

7. The method for preparing phenethyltrialkoxysilane according to claim 1, characterized in that: In step C, the vacuum degree of the vacuum distillation is 0.098 MPa, and the fraction with a temperature of 100-140° C. at the top of the distillation tower is collected as the finished product.

8. The method for preparing phenethyltrialkoxysilane according to claim 1, characterized in that: Based on the mol amount of trialkoxysilane, the mass yield of the prepared phenethyltrialkoxysilane product is above 85%.

9. The method for preparing phenethyltrialkoxysilane according to claim 1, characterized in that: The reaction mechanism of the preparation method is: CH2=CHC6H5+HSi(OR)3→C6H5CH2CH2Si(OR)3; Or CH2=CHC6H5 +HSiR'(OR)2→C6H5CH2CH2SiR'(OR)2; Wherein, R=alkyl, including methyl, ethyl or propyl; R'=methyl; in the case of R=methyl, phenethyltrimethoxysilane or phenethylmethyldimethoxysilane is obtained; in the case of R=ethyl, phenethyltriethoxysilane is obtained.