JPS6228955B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a new and improved method for producing fluorosilane, and particularly to an industrially advantageous method for producing fluorosilane. In recent years, fluorosilane has attracted attention as a heat-resistant refrigerant or an intermediate in organic synthesis. As a general method for synthesizing this fluorosilane, a method is known in which a suitable fluoride is reacted with the corresponding chlorosilane. Examples of the fluoride include hydrogen fluoride, antimony trifluoride, and antimony trifluoride-antimony pentachloride. , zinc fluoride, potassium fluoride-hydrogen fluoride, ammonium fluoride, silver fluoride, or silver fluoride. However, among the above-mentioned fluorides, hydrogen fluoride, antimony trifluoride, antimony trifluoride-antimony pentachloride are toxic and dangerous to handle, and silver compounds such as silver fluoride are expensive. Therefore, the use of large amounts causes economic disadvantages, and furthermore, zinc fluoride has problems such as post-treatment being relatively difficult. The present invention provides a method for producing fluorosilane that solves the conventional problems as described above, and is based on the general formula R _(2o+2)-n Si _o Cl _n ...(i)ゝR is an unsubstituted monovalent hydrocarbon group, n is 1
An integer of ~5, m is an integer greater than or equal to 1, where m<2n
The general formula R _(2o+2)-n Si _o F _n ...(ii) (where R, m and n has the same meaning as above). The present inventors have conducted extensive research with the aim of solving the above-mentioned problems regarding the method of producing fluorosilane from chlorosilane, and have found that relatively inexpensive cupric fluoride has a good fluorination effect. The present invention has been completed based on the following findings: (1) The fluorination reaction proceeds extremely easily (proceeds exothermically in most cases) at temperatures between 0°C and room temperature, resulting in the formation of cupric fluoride as cupric fluoride. Use commercially available dihydrate as is〓〓〓〓〓
However, chlorination takes precedence, and there is almost no effect of water. (2) All the fluorine atoms in cupric fluoride participate in the reaction, and by-product copper chloride can be reliably precipitated by adding a hydrocarbon solvent. (3) The steric configuration of the carbon bonded to the silicon atom is not affected in any way, and in the conventional method, the starting material chlorosilane has no hydrogen-silicon bond. However, in the present invention, such cleavage does not occur, and the hydrogen-silicon bond remains intact. The method of the present invention will be explained in detail below. The chlorosilane used as the starting material in the present invention is represented by the above general formula (i),
R in the formula represents an unsubstituted monovalent hydrocarbon group, including alkyl groups such as methyl, ethyl, propyl, butyl or octyl, cycloalkyl such as cyclopentyl or cyclohexyl, vinyl or alkenyl groups such as allyl groups, and aryl groups such as phenyl groups and tolyl groups. m and n are as described above. In the present invention, various conventionally known chlorosilanes can be used as long as they satisfy the above general formula. In addition, as the cupric fluoride used together with the above silane, commonly available commercially available cupric fluoride
An ethereal suspension of copper can be used. The reaction in the method of the present invention is shown in the reaction formula below. R _(2o+2)-n Si _o Cl _n +1/2m・CuF ₂・2H ₂ O→R _(2o+2)-n Si _o F _n +1/2m・CuCl ₂ (+2H ₂ O) (However, R , m and n have the same meanings as above) In the reaction according to the method of the present invention, for example, chlorosilane is added to the ether solution of cupric fluoride described above
℃ to room temperature and under atmospheric pressure, it proceeds easily by simply dropping it dropwise (stirring may be performed if necessary),
The production of the target fluorosilane can be easily confirmed by gas chromatography analysis. Note that the reaction product contains copper chloride as a by-product, but this copper chloride can be completely precipitated by adding a hydrocarbon solvent such as pentane, and the desired fluorosilane and copper chloride are It can be separated by filtration. Regarding the usage ratio (reaction molar ratio) of the chlorosilane and cupric fluoride, it is preferable to use an amount of cupric fluoride that converts all of the chlorine atoms in the chlorosilane to fluorine atoms. Note that when carrying out the method of the present invention, a reaction solvent may be used, and ether is generally used as the reaction solvent. The reaction also proceeds in hydrocarbon solvents such as pentane and octane, but the reaction rate in these is slightly slower than in ether. Next, examples of the present invention will be given, but the present invention is not limited thereto. Example 1 Diphenyldichlorosilane 1.25g (4.9mmol)
Cupric fluoride dihydrate (CuF ₂ 2H ₂ O) 0.70g
(5.1 mmol) in ether (5 ml) was gradually added dropwise at room temperature, and after completion of the dropwise addition, the mixture was stirred at room temperature for 1 hour. Then, after adding 5 ml of pentane, suction filtration was performed, the resulting filtration residue was washed with 5 ml of pentane, and the filtrate and washing solution were combined. Next, the solvent was distilled off and distilled under reduced pressure at an oil bath temperature of 180°C.
0.995 g of fraction up to 18 mmHg was obtained. This product was confirmed to be diphenyldifluorosilane by gas chromatography analysis (yield 89%). Example 2 Phenyldimethylchlorosilane 0.96g
(5.63mmol), cupric fluoride 0.418g (3.04mmol)
The treatment was carried out in substantially the same manner as in Example 1 above using 5 ml of ether and 0.5552 g of a fraction up to an oil bath temperature of 120° C./18 mmHg was obtained. This product was confirmed to be phenylmethyldifluorosilane by gas chromatography analysis (yield 64%). Example 3 〓〓〓〓〓
To a suspension of 0.752 g (5.4 mmol) of cupric fluoride dihydrate in ether (10 ml), 1.612 g (9.7 mmol) of pentamethylchlorosilane was gradually added dropwise at room temperature. The progress of the reaction was monitored by gas chromatography analysis, and after the reaction was completed, the treatment was carried out according to Example 1, and 0.971 g of pentamethylfluorodisilane was obtained as a fraction with a boiling point of 90 to 100°C (yield: 67 %). Example 4 To a suspension of 3.6 g (26 mmol) of cupric fluoride dihydrate in ether (15 ml), 3.6 g (15.7 mmol) of endo-norbornyltrichlorosilane was added under water cooling (0
When the solution was added dropwise over a period of 3 minutes at a temperature of 100.degree. C., a colored liquid was obtained. After stirring this liquid at room temperature for 12 hours, 15 ml of pentane was added.
Then, suction filtration was performed and the residue was washed with pentane. When the filtrate and washing solution were dried with sodium sulfate and distilled, endo-norponyltrifluorosilane was found as a fraction with a boiling point of 57-58℃/68mmHg at 2.10%.
g (yield 74%). Example 5 To a suspension of 0.950 g (6.9 mmol) of cupric fluoride dihydrate in ether (5 ml), 0.706 g (3.3 mmol) of n-octyldichlorosilane was gradually added dropwise at 0°C. After the completion of the reaction, stirring was continued for 5 minutes at the same temperature. Then, the same treatment as in Example 1 was carried out, and n-octyldifluorosilane was obtained with a yield of 74%. Examples 6 to 9 Silanes shown in the table below and dihydrate of cupric fluoride were reacted under the conditions shown in the table, and then treated in substantially the same manner as in Example 1.
The products shown in the table below were obtained.

[Table] 〓〓〓〓〓

Claims (1)

[Claims] 1 General formula R _(2o+2)-n Si _o Cl _n (wherein, R is an unsubstituted monovalent hydrocarbon group, and n is 1
An integer of ~5, m is a positive integer of 1 or more, provided that m<
2n+2)
A method for producing fluorosilane represented by the general formula R _(2o+2)-n Si _o F _n (wherein R, m and n have the same meanings as above), characterized by reacting with steel. .