Preparation method of (3, 3, 3-trifluoropropyl) methyl dichlorosilane

Abstract

The invention relates to a novel catalyst for preparing trifluoropropyl methyl dichlorosilane, and 3, 3, 3-trifluoropropene and methyl dichlorosilane react under the action of a platinum-tetrahydrofuran catalyst to prepare (3, 3, 3-trifluoropropyl) methyl dichlorosilane. The method comprises the following steps: introducing 3, 3, 3-trifluoropropene into a mixture of a catalyst and methyl dichlorosilane at a set temperature in an air atmosphere, and stirring to react; the method has the characteristics of simple operation, mild reaction conditions, high target product yield, high selectivity and the like. The obtained product (3, 3, 3-trifluoropropyl) dichloromethylsilane is an important precursor of a monomer of fluorosilicone rubber. The core of the invention is innovation of a traditional catalyst, and the catalyst can improve the yield and selectivity and reduce the loss of a substrate.

Description

Technical Field

[0001] This patent belongs to the field of synthesis of organic silicon compounds, and specifically relates to a method for preparing (3,3,3-trifluoropropyl)methyldichlorosilane. Background Art

[0002] Fluorosilicone rubber is a special synthetic material with a main chain of silicon oxygen structure and a side chain of methyl and trifluoropropyl structure. It is mainly obtained by ring-opening polymerization of 1,3,5-trimethyl-1,3,5-tri(3,3,3-trifluoropropyl)cyclotrisiloxane (D3F). The special chemical structure of this material gives it many unique functions. The Si-O-Si structure of the main chain gives fluorosilicone rubber flexibility and thermal stability, while the side chain structure of trifluoropropyl gives fluorosilicone rubber good oil resistance and solvent resistance. The simpler method for preparing 1,3,5-trimethyl-1,3,5-tri(3,3,3-trifluoropropyl)cyclotrisiloxane (D3F) is to hydrolyze (3,3,3-trifluoropropyl)methyldichlorosilane. Therefore, an efficient and simple preparation of (3,3,3-trifluoropropyl)methyldichlorosilane is very necessary.

[0003] At present, for the preparation method of (3,3,3-trifluoropropyl)methyldichlorosilane, there are data indicating that a homogeneous catalyst, namely a Speier catalyst, can be used, because the Speier catalyst can be more evenly dispersed in the reaction system, has good stability, and the homogeneous catalyst has a higher catalytic activity. However, when the Speier catalyst is used, because the hydroxyl contained in the solvent is isopropanol and reacts with methyldichlorosilane, the yield and selectivity are low, and unnecessary loss of methyldichlorosilane is caused. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides a new catalyst for preparing (3,3,3-trifluoropropyl)methyldichlorosilane. The catalyst greatly improves the yield and selectivity of (3,3,3-trifluoropropyl)methyldichlorosilane.

[0005] The technical solution of the present invention is as follows:

[0006] A (3,3,3-trifluoropropyl)methyldichlorosilane having the following structure:

[0007]

[0008] According to the present invention, the above-mentioned preparation method of (3,3,3-trifluoropropyl)dichloromethylsilane comprises the following steps:

[0009] At a set temperature, trifluoropropylene is introduced into a mixed system of methyldichlorosilane and a catalyst, and stirred for reaction. The reactor is cooled in an ice bath before the reaction.

[0010] Preferably, the reaction temperature is 50-80°C.

[0011] Preferably, the reaction time is 1-3 h.

[0012] Preferably, the catalyst is an organic solvent for chloroplatinic acid.

[0013] Preferably, the organic solvent is tetrahydrofuran

[0014] Preferably, the mass ratio of the catalyst to methyldichlorosilane is 1-10:10000.

[0015] Preferably, the molar ratio of trifluoropropylene to methyldichlorosilane is 1:1-1.5.

[0016] According to the method for preparing (3,3,3-trifluoropropyl)methyldichlorosilane of the present invention, a preferred embodiment comprises the following steps:

[0017] (1) Add methyldichlorosilane and a tetrahydrofuran solution of chloroplatinic acid into the reaction kettle, wherein the mass ratio of the catalyst to methyldichlorosilane is 1-10:10000.

[0018] (2) Raise the temperature of the material to 50-80°C, introduce trifluoropropylene using a high-pressure constant flow pump, and mechanically stir to carry out a hydrosilylation reaction;

[0019] (3) After the trifluoropropylene is passed through, the reaction temperature is maintained at 50-80°C and the reaction is continued with stirring for 1-3 hours;

[0020] (4) After the reaction is completed, the reactor is cooled to a low temperature of 10 to 20°C and the exhaust valve is opened to release the pressure; (5) The product is transferred to a receiving bottle, and a sample is taken for GC determination. The yield and selectivity of (3,3,3-trifluoropropyl)dichloromethylsilane are calculated by the internal standard method;

[0021] The reaction equation of the present invention is

[0022]

[0023] The beneficial effects of this application include:

[0024] (1) Compared with other reported homogeneous reactions, the yield and selectivity are greatly improved and the formation of by-products is reduced.

[0025] (2) The catalyst of the present invention has better catalytic performance than the traditional Speier catalyst.

[0026] (3) The preparation method of the present invention has simple process, easy operation, and is easy to realize industrial production, thereby reducing costs.

[0027] The method has the characteristics of simple operation, mild reaction conditions, high yield of target product, high selectivity, etc. The obtained product (3,3,3-trifluoropropyl)dichloromethylsilane is an important precursor of fluorosilicone rubber monomer. The core of the invention is the innovation of traditional catalysts, which can improve the yield and selectivity and reduce the loss of substrate. DETAILED DESCRIPTION

[0028] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0029] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0030] Example 1

[0031] 1. Add 369 g (3.2 mol) of methyldichlorosilane and 9 ml × 0.02 g / ml of chloroplatinic acid-tetrahydrofuran catalyst (0.5 wt‰ of methyldichlorosilane; calculated as chloroplatinic acid) into the reaction kettle;

[0032] 2. Raise the temperature of the material to 60°C, introduce 276 g (2.9 mol) of trifluoropropylene using a high-pressure pump, and stir mechanically to carry out a hydrosilylation reaction;

[0033] 3. After passing trifluoropropylene, maintain the temperature at 60°C and continue stirring the reaction for 3 hours.

[0034] 4. After the reaction is completed, lower the reactor temperature to 10-20°C and open the exhaust valve to release the pressure.

[0035] 5. Transfer 670.4 g of the product to a receiving bottle and take a sample for GC determination. The internal standard method is used to calculate the yield of (3,3,3-trifluoropropyl)dichloromethylsilane to be 98.0% and the selectivity to be 99%.

[0036] Example 2

[0037] 1. Add 19.5g (0.169mol) of methyldichlorosilane and 0.5ml×0.02g / ml of chloroplatinic acid-tetrahydrofuran catalyst (0.5wt‰ of methyldichlorosilane feed amount; calculated as chloroplatinic acid) into the reactor.

[0038] 2. Heat the material to 80°C, introduce 14.8 g (0.154 mol) of trifluoropropylene using a high-pressure pump, and stir mechanically to carry out a hydrosilylation reaction;

[0039] 3. After passing trifluoropropylene, maintain the temperature at 80°C and continue stirring the reaction for 1 hour.

[0040] 4. After the reaction is completed, lower the reactor temperature to 10-20°C and open the exhaust valve to release the pressure.

[0041] 5. The product was transferred to a receiving bottle and sampled for GC determination. The internal standard method was used to calculate the yield of (3,3,3-trifluoropropyl)dichloromethylsilane to be 92.9% and the selectivity to be 94.4%.

[0042] Example 3

[0043] 1. Add 26.1g (0.228mol) of methyldichlorosilane and 1ml×0.02g / ml of chloroplatinic acid-tetrahydrofuran catalyst into the reaction kettle; (1wt‰ of methyldichlorosilane feed; calculated as chloroplatinic acid)

[0044] 2. Raise the temperature of the material to 60°C, use a high-pressure pump to introduce 14.5 g (0.152 mol) of trifluoropropylene, and mechanically stir to carry out the hydrosilylation reaction;

[0045] 3. After passing trifluoropropylene, maintain the temperature at 60°C and continue stirring the reaction for 3 hours.

[0046] 4. After the reaction is completed, lower the reactor temperature to 10-20°C and open the exhaust valve to release the pressure.

[0047] 5. The product was transferred to a receiving bottle and sampled for GC determination. The internal standard method was used to calculate the yield of (3,3,3-trifluoropropyl)dichloromethylsilane to be 90.7% and the selectivity to be 92.3%.

[0048] Comparative Example 1

[0049] 1. Add 19.7 g (0.171 mol) of methyldichlorosilane and 0.5 ml × 0.02 g / ml of chloroplatinic acid-tetrahydrofuran catalyst (0.5 wt‰ of methyldichlorosilane feed amount; calculated as chloroplatinic acid) into the reactor.

[0050] 2. Heat the material to 120°C, introduce 15.8 g (0.164 mol) of trifluoropropylene using a high-pressure pump, and stir mechanically to carry out a hydrosilylation reaction;

[0051] 3. After passing trifluoropropylene, maintain the temperature at 120°C and continue stirring the reaction for 3 hours.

[0052] 4. After the reaction is completed, lower the reactor temperature to 10-20°C and open the exhaust valve to release the pressure.

[0053] 5. The product was transferred to a receiving bottle and sampled for GC determination. The internal standard method was used to calculate the yield of (3,3,3-trifluoropropyl)dichloromethylsilane to be 55.2% and the selectivity to be 60.4%. High temperature will cause the catalyst to lose its catalytic activity, resulting in a decrease in yield.

[0054] Comparative Example 2

[0055] 1. Add 19.3g (0.168mol) of methyldichlorosilane and 0.5ml×0.02g / ml of tetrahydrofuran solution of chloroplatinic acid (0.5wt‰ of methyldichlorosilane feed amount; calculated as chloroplatinic acid) into the reactor.

[0056] 2. Raise the temperature of the material to 30°C, use a high-pressure pump to introduce 15.1 g (0.157 mol) of trifluoropropylene, and mechanically stir to carry out a hydrosilylation reaction;

[0057] 3. After passing trifluoropropylene, maintain the temperature at 30°C and continue stirring the reaction for 3 hours.

[0058] 4. After the reaction is completed, lower the reactor temperature to 10-20°C and open the exhaust valve to release the pressure.

[0059] 5. The product was transferred to a receiving bottle, and samples were taken for GC determination. The internal standard method was used to calculate the yield of (3,3,3-trifluoropropyl)dichloromethylsilane to be 1.3% and the selectivity to be 10.6%. The catalyst was not activated at room temperature, resulting in poor catalytic effect.

[0060] Comparative Example 3

[0061] 1. Add 19.3g (0.168mol) of methyldichlorosilane and 0.5ml×0.02g / ml of chloroplatinic acid-isopropanol catalyst into the reactor; (0.5wt‰ of methyldichlorosilane feed; calculated as chloroplatinic acid)

[0062] 2. Raise the temperature of the material to 60°C, use a high-pressure pump to introduce 14.9 g (0.155 mol) of trifluoropropylene, and mechanically stir to carry out a hydrosilylation reaction;

[0063] 3. After passing trifluoropropylene, maintain the temperature at 60°C and continue stirring the reaction for 3 hours.

[0064] 4. After the reaction is completed, lower the reactor temperature to 10-20°C and open the exhaust valve to release the pressure.

[0065] 5. Transfer the product to a receiving bottle and take a sample for GC determination. The internal standard method is used to calculate the yield of (3,3,3-trifluoropropyl)dichloromethylsilane to be 72.5% and the selectivity to be 73.6%. Methyldichlorosilane will react with the hydroxyl group in isopropanol, resulting in the loss of the reaction substrate.

[0066] Comparative Example 4

[0067] 1. Add 19.8g (0.172mol) of methyldichlorosilane and 0.5ml×0.02g / ml of chloroplatinic acid-ethanol catalyst into the reactor; (0.5wt‰ of methyldichlorosilane feed; calculated as chloroplatinic acid)

[0068] 2. Raise the temperature of the material to 60°C, use a high-pressure pump to introduce 15.9 g (0.165 mol) of trifluoropropylene, and mechanically stir to carry out a hydrosilylation reaction;

[0069] 3. After passing trifluoropropylene, maintain the temperature at 60°C and continue stirring the reaction for 3 hours.

[0070] 4. After the reaction is completed, lower the reactor temperature to 10-20°C and open the exhaust valve to release the pressure.

[0071] 5. The product was transferred to a receiving bottle and sampled for GC determination. The internal standard method was used to calculate the yield of (3,3,3-trifluoropropyl)dichloromethylsilane to be 63.5% and the selectivity to be 65.6%.

[0072] Comparative Example 5

[0073] 1. Add 19.3g (0.168mol) of methyldichlorosilane and 0.5ml×0.02g / ml of chloroauric acid-tetrahydrofuran catalyst into the reaction kettle; (0.5wt‰ of methyldichlorosilane feed; calculated as chloroplatinic acid)

[0074] 2. Raise the temperature of the material to 60°C, use a high-pressure pump to introduce 15.2 g (0.158 mol) of trifluoropropylene, and mechanically stir to carry out a hydrosilylation reaction;

[0075] 3. After passing trifluoropropylene, maintain the temperature at 60°C and continue stirring the reaction for 3 hours.

[0076] 4. After the reaction is completed, lower the reactor temperature to 10-20°C and open the exhaust valve to release the pressure.

[0077] 5. The product was transferred to a receiving bottle, and a sample was taken for GC determination. The yield of (3,3,3-trifluoropropyl)dichloromethylsilane was 12.7% and the selectivity was 25.1% by the internal standard method. The effect of gold as a catalyst was not good, methyldichlorosilane was not completely converted, and some by-products were formed.

[0078] Comparative Example 6

[0079] 1. Add 19.3g (0.168mol) of methyldichlorosilane and 0.5ml×0.02g / ml of sodium chloroplatinate-tetrahydrofuran catalyst into the reaction kettle; (0.5wt‰ of methyldichlorosilane feed amount; calculated as chloroplatinic acid)

[0080] 2. Raise the temperature of the material to 60°C, use a high-pressure pump to introduce 15.2 g (0.158 mol) of trifluoropropylene, and mechanically stir to carry out a hydrosilylation reaction;

[0081] 3. After passing trifluoropropylene, maintain the temperature at 60°C and continue stirring the reaction for 3 hours.

[0082] 4. After the reaction is completed, lower the reactor temperature to 10-20°C and open the exhaust valve to release the pressure.

[0083] 5. The product was transferred to a receiving bottle, and a sample was taken for GC determination. The internal standard method was used to calculate the yield of (3,3,3-trifluoropropyl)dichloromethylsilane to be 31.6% and the selectivity to be 53.1%. Sodium ions have an effect on the reaction.

[0084] Comparative Example 7

[0085] 1. Add 19.6g (0.170mol) of methyldichlorosilane and 0.5ml×0.02g / ml of chloroplatinic acid-tetrahydrofuran catalyst into the reactor; (0.5wt‰ of methyldichlorosilane feed; calculated as chloroplatinic acid)

[0086] 2. Raise the temperature of the material to 60°C, use a high-pressure pump to introduce 15.8 g (0.164 mol) of trifluoropropylene, and mechanically stir to carry out a hydrosilylation reaction;

[0087] 3. After passing trifluoropropylene, maintain the temperature at 60°C and continue stirring the reaction for 30 minutes.

[0088] 4. After the reaction is completed, lower the reactor temperature to 10-20°C and open the exhaust valve to release the pressure.

[0089] 5. The product was transferred to a receiving bottle and sampled for GC determination. The internal standard method was used to calculate the yield of (3,3,3-trifluoropropyl)dichloromethylsilane to be 58.6% and the selectivity to be 89.7%. The reaction was not completed within 30 minutes.

[0090] Comparative Example 8

[0091] 1. Add 19.5g (0.170mol) of methyldichlorosilane and 0.5ml×0.02g / ml of chloroplatinic acid-tetrahydrofuran catalyst into the reactor; (0.5wt‰ of methyldichlorosilane feed)

[0092] 2. Raise the temperature of the material to 60°C, use a high-pressure pump to introduce 20.5 g (0.214 mol) of trifluoropropylene, and mechanically stir to carry out the hydrosilylation reaction;

[0093] 3. After passing trifluoropropylene, maintain the temperature at 60°C and continue stirring the reaction for 30 minutes.

[0094] 4. After the reaction is completed, lower the reactor temperature to 10-20°C and open the exhaust valve to release the pressure.

[0095] 5. The product was transferred to a receiving bottle and sampled for GC determination. The internal standard method was used to calculate the yield of (3,3,3-trifluoropropyl)dichloromethylsilane to be 72.5% and the selectivity to be 73.6%.

[0096] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for preparing (3,3,3-trifluoropropyl)methyldichlorosilane, characterized in that: Trifluoropropylmethyldichlorosilane has the following structure: The steps include: In an air atmosphere, at 50-80° C., trifluoropropylene is introduced into a mixture of a platinum-tetrahydrofuran catalyst and methyldichlorosilane, and stirred for reaction; thus, trifluoropropylmethyldichlorosilane is obtained.

2. The preparation method according to claim 1, characterized in that: The reaction temperature is preferably 55-70°C, more preferably 60-65°C.

3. The preparation method according to claim 1 or 2, characterized in that: The reaction time is 1-3 h, preferably 1.2-2.5 h, more preferably 1.5-2 h.

4. The preparation method according to claim 1, characterized in that: The molar ratio of trifluoropropylene to methyldichlorosilane is 1:1-1.5, preferably 1:1-1.

2.

5. The preparation method according to claim 1, The mass ratio of the catalyst chloroplatinic acid to methyldichlorosilane is 1-10:10000, preferably 3-7:10000, and more preferably 4-6:10000.

6. The preparation method according to claim 1 or 5, characterized in that: The catalyst concentration is 0.01-0.05 g / ml (calculated as chloroplatinic acid), preferably 0.02-0.03 g / ml (calculated as chloroplatinic acid).

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