A method for purifying 3,3,3-trifluoropropylethoxydimethylsilane

Abstract

This invention discloses a method for purifying 3,3,3-trifluoropropylethoxydimethylsilane. The crude 3,3,3-trifluoropropylethoxydimethylsilane mainly contains 3,3,3-trifluoropropylmethyldiethoxysilane as an impurity. The purification steps include: dissolving the crude 3,3,3-trifluoropropylethoxydimethylsilane in an organic solvent, adding magnesium, and then adding a methyl source reagent dropwise. After the addition is complete, the mixture is heated to reflux and reacted. After the reaction is complete, excess magnesium is removed by filtration. Sodium sulfite solid is added to the filtrate and stirred until the mixture becomes colorless and transparent. Excess sodium sulfite solid is removed by filtration, and the filtrate is distilled to obtain the product. The advantages of this invention are: simple operation, mild reaction, high product purity, and suitability for industrial application.

Description

Technical Field

[0001] This invention relates to the field of organosilane purification technology, specifically to the purification of 3,3,3-trifluoropropylethoxydimethylsilane. Background Technology

[0002] Currently, the main method reported both domestically and internationally for preparing high-purity 3,3,3-trifluoropropylethoxydimethylsilane involves reacting 3,3,3-trifluoropropyldimethylchlorosilane with ethanol to generate the target product. However, this method results in high-purity chlorosilane at a relatively high cost.

[0003] Currently, the purity of reagents provided by domestic reagent companies is 98%, and there are no reports of 3,3,3-trifluoropropylethoxydimethylsilane with higher purity.

[0004] To this end, the applicant has developed a purification method that can greatly improve the purity of 3,3,3-trifluoropropylethoxydimethylsilane. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method for purifying 3,3,3-trifluoropropylethoxydimethylsilane, which is simple in steps, easy to operate, mild in reaction, and produces high-purity products, and is suitable for industrial application.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is: a method for purifying 3,3,3-trifluoropropylethoxydimethylsilane, wherein the impurities in the crude 3,3,3-trifluoropropylethoxydimethylsilane mainly include 3,3,3-trifluoropropylmethyldiethoxysilane. The purification steps include: dissolving the crude 3,3,3-trifluoropropylethoxydimethylsilane in an organic solvent, adding magnesium, adding a methyl source reagent dropwise, heating and refluxing after the addition is complete, filtering to remove excess magnesium after the reaction is complete, adding sodium sulfite solid to the filtrate and stirring until it becomes colorless and transparent, filtering to remove excess sodium sulfite solid, and distilling the filtrate to obtain the product.

[0007] The structural formula of 3,3,3-trifluoropropylethoxydimethylsilane is shown in Formula 1: (Formula 1); The structural formula of 3,3,3-trifluoropropylmethyldiethoxysilane is shown in Formula 2: (Formula 2).

[0008] Furthermore, in the aforementioned purification method for 3,3,3-trifluoropropylethoxydimethylsilane, the crude 3,3,3-trifluoropropylethoxydimethylsilane contains 65%–70% 3,3,3-trifluoropropylethoxydimethylsilane by mass, and 20%–30% 3,3,3-trifluoropropylmethyldiethoxysilane by mass.

[0009] Furthermore, in the aforementioned method for purifying 3,3,3-trifluoropropylethoxydimethylsilane, the organic solvent is one or a mixture of two of diethyl ether and tetrahydrofuran.

[0010] Furthermore, in the aforementioned method for purifying 3,3,3-trifluoropropylethoxydimethylsilane, the molar ratio of 3,3,3-trifluoropropylethoxydimethylsilane to magnesium in the crude 3,3,3-trifluoropropylethoxydimethylsilane is 1:0.6~0.65.

[0011] Furthermore, in the aforementioned method for purifying 3,3,3-trifluoropropylethoxydimethylsilane, iodomethane is used as the methyl source reagent.

[0012] Furthermore, in the aforementioned method for purifying 3,3,3-trifluoropropylethoxydimethylsilane, the molar ratio of 3,3,3-trifluoropropylethoxydimethylsilane to the methyl source reagent in the crude 3,3,3-trifluoropropylethoxydimethylsilane is 1:0.4~0.45.

[0013] Furthermore, in the aforementioned method for purifying 3,3,3-trifluoropropylethoxydimethylsilane, the reflux reaction time is 1-2 hours.

[0014] Furthermore, in the aforementioned method for purifying 3,3,3-trifluoropropylethoxydimethylsilane, the mass of sodium sulfite solid is 20% to 25% of the crude mass of 3,3,3-trifluoropropylethoxydimethylsilane.

[0015] Furthermore, in the aforementioned purification method for 3,3,3-trifluoropropylethoxydimethylsilane, the distillation conditions are a 60cm distillation column, atmospheric pressure, nitrogen protection, and a top temperature of 120~125℃.

[0016] The advantages of this invention are: the purification method for 3,3,3-trifluoropropylethoxydimethylsilane described in this invention has fewer process steps, is simple and easy to operate, can effectively remove the impurity 3,3,3-trifluoropropylmethyldiethoxysilane, greatly improve the purity of the finished product to 99.5% or higher, and is suitable for industrial promotion. Detailed Implementation

[0017] The present invention will now be described in further detail with reference to preferred embodiments.

[0018] Example 1: 154g of crude 3,3,3-trifluoropropylethoxydimethylsilane (purity 65%, i.e., containing 100g of 3,3,3-trifluoropropylethoxydimethylsilane) was mixed evenly with 200ml of diethyl ether. 7.2g of magnesium was added, followed by the dropwise addition of 28.4g of iodomethane. After the addition was complete, the temperature was raised to 35°C and refluxed for 1 hour. After the reaction was complete, the temperature was lowered to 20°C–25°C. Excess magnesium shavings were removed by suction filtration. 20g of anhydrous sodium sulfite solid was added to the filtrate and stirred for 30 minutes until it became colorless and transparent. The solid was then removed by filtration. The filtrate was distilled at atmospheric pressure using a 60cm distillation column under nitrogen protection. 88g of the product with a peak temperature of 120–125°C and a GC purity of 99.6% was collected.

[0019] Example 2: 285.7 g of crude 3,3,3-trifluoropropylethoxydimethylsilane (purity 70%, i.e., containing 200 g of 3,3,3-trifluoropropylethoxydimethylsilane) was mixed evenly with 400 ml of tetrahydrofuran. 15.6 g of magnesium was added, followed by dropwise addition of 63.9 g of iodomethane. After the addition was complete, the temperature was raised to 67°C and refluxed for 2 hours. After the reaction was complete, the temperature was lowered to 20°C–25°C. Excess magnesium shavings were removed by suction filtration. 50 g of anhydrous sodium sulfite solid was added to the filtrate and stirred for 20 minutes until colorless and transparent. The solid was then removed by filtration. The filtrate was distilled at atmospheric pressure using a 60 cm distillation column under nitrogen protection. 180 g of the product with a peak temperature of 120–125°C was obtained, with a GC purity of 99.5%.

[0020] Example 3: 147g of crude 3,3,3-trifluoropropylethoxydimethylsilane (purity 68%, i.e., containing 100g of 3,3,3-trifluoropropylethoxydimethylsilane) was mixed evenly with 200ml of tetrahydrofuran. 7.8g of magnesium was added, and 31.95g of iodomethane was added dropwise. After the addition was complete, the temperature was raised to 67°C and refluxed for 1.5h. After the reaction was complete, the temperature was lowered to 20°C-25°C. Excess magnesium shavings were removed by suction filtration. 25g of anhydrous sodium sulfite solid was added to the filtrate and stirred for 30min until it became colorless and transparent. The solid was then removed by filtration. The filtrate was distilled at atmospheric pressure using a 60cm distillation column under nitrogen protection. 86g of the product with a peak temperature of 120-125°C was obtained, with a GC purity of 99.7%.

[0021] Example 4: 746g of crude 3,3,3-trifluoropropylethoxydimethylsilane (purity 67%, i.e., containing 500g of 3,3,3-trifluoropropylethoxydimethylsilane) was mixed evenly with 1000ml of diethyl ether. 36g of magnesium was added, and 142g of iodomethane was added dropwise. After the addition was complete, the temperature was raised to 35°C and refluxed for 2 hours. After the reaction was complete, the temperature was lowered to 20°C–25°C. Excess magnesium shavings were removed by filtration. 100g of anhydrous sodium sulfite solid was added to the filtrate and stirred for 45 minutes until it became colorless and transparent. The solid was then removed by filtration. The filtrate was distilled at atmospheric pressure using a 60cm distillation column under nitrogen protection. 460g of the product with a peak temperature of 120–125°C was obtained, with a GC purity of 99.6%.

[0022] As can be seen from the above embodiments, the purification method for 3,3,3-trifluoropropylethoxydimethylsilane of the present invention has few process steps, is simple and easy to operate, can effectively remove the impurity 3,3,3-trifluoropropylmethyldiethoxysilane, greatly improve the purity of the finished product, and is suitable for industrial promotion.

Claims

1. A method for purifying 3,3,3-trifluoropropylethoxydimethylsilane, wherein the impurities in the crude 3,3,3-trifluoropropylethoxydimethylsilane mainly comprise 3,3,3-trifluoropropylmethyldiethoxysilane, characterized in that: The purification steps include: dissolving crude 3,3,3-trifluoropropylethoxydimethylsilane in an organic solvent, adding magnesium, adding methyl source reagent dropwise, heating and refluxing after the addition is complete, filtering to remove excess magnesium after the reaction is complete, adding sodium sulfite solid to the filtrate and stirring until it is colorless and transparent, filtering to remove excess sodium sulfite solid, and distilling the filtrate to obtain the product.

2. The purification method for 3,3,3-trifluoropropylethoxydimethylsilane according to claim 1, characterized in that: The crude product of 3,3,3-trifluoropropylethoxydimethylsilane contains 65% to 70% 3,3,3-trifluoropropylethoxydimethylsilane by mass, and 20% to 30% 3,3,3-trifluoropropylmethyldiethoxysilane by mass.

3. The purification method for 3,3,3-trifluoropropylethoxydimethylsilane according to claim 1, characterized in that: The organic solvent is one or a mixture of two of diethyl ether and tetrahydrofuran.

4. The purification method for 3,3,3-trifluoropropylethoxydimethylsilane according to claim 1, characterized in that: In the crude product of 3,3,3-trifluoropropylethoxydimethylsilane, the molar ratio of 3,3,3-trifluoropropylethoxydimethylsilane to magnesium is 1:0.6~0.

65.

5. The purification method for 3,3,3-trifluoropropylethoxydimethylsilane according to claim 1, characterized in that: Iodomethane was used as the methyl source reagent.

6. The purification method for 3,3,3-trifluoropropylethoxydimethylsilane according to claim 5, characterized in that: In the crude product of 3,3,3-trifluoropropylethoxydimethylsilane, the molar ratio of 3,3,3-trifluoropropylethoxydimethylsilane to the methyl source reagent is 1:0.4~0.

45.

7. The purification method for 3,3,3-trifluoropropylethoxydimethylsilane according to claim 1, characterized in that: The reflux reaction time is 1-2 hours.

8. The purification method for 3,3,3-trifluoropropylethoxydimethylsilane according to claim 1, characterized in that: The solid sodium sulfite accounts for 20% to 25% of the crude mass of 3,3,3-trifluoropropylethoxydimethylsilane.

9. The purification method for 3,3,3-trifluoropropylethoxydimethylsilane according to claim 1, characterized in that: The distillation conditions were a 60cm distillation column, atmospheric pressure, nitrogen protection, and a top temperature of 120~125℃.