DE1087603B - Process for the production of ª ‰ -Cyanaethyltrichlorosilane - Google Patents

Description

Process for the production of ß-cyanoethyltrichlorosilane The invention relates to a process for the production of fl-cyanoethyltrichlorosilane by reacting trichlorosilane with acrylonitrile at elevated temperature, which is characterized in that the reaction is carried out at a temperature between 40 and 350 "C in the presence of a catalyst carries out either an organophosphorus halide of the formula - (sv) wherein R 'is a preferably aromatic hydrocarbon radical, X is a halogen atom and y is the number 1 or 2, or a heterocyclic amine with one or more heterocyclic rings consisting only of carbon and nitrogen - Or consist only of carbon, nitrogen and sulfur atoms and the ring atoms of which may carry alkyl or aryl substituents, or a diarylamine, or an organophosphonate of the formula where R ", R"'and R "" stand for identical or different aryl radicals, or is a dialkylcyanamide.

Processes are known according to which the double bond is unsaturated Nitrile silanes can optionally be added in the presence of catalysts.

Compounds of the elements of group IIIa, IVa, Ib, II or metals of group VIII of the periodic table and their compounds as well as organic peroxide catalysts are known as catalysts. However, these processes have the disadvantage that the yields are very low because they are due to undesired side reactions catalyst H2C = CH-CN t HSiCl3 to H2C-CH-CN II Cl3Si H Suitable catalysts are organophosphorus halides. They have the general formula R -PX <3 where R 'is a hydrocarbon group, e.g. B. an alkyl or aryl group such as methyl, ethyl, propyl, butyl, phenyl, tolyl or naphthyl group, X is a halogen atom such as a chlorine or bromine atom and y is the number 1 or 2. The phosphorus halide compounds preferred as catalyst for carrying out the process, the reaction mixture consists of a number of different possible addition products. In the present invention, these disadvantages are avoided in that the addition of the silane radical in the β-position is steered by the above-mentioned catalysts, ie the silyl group attaches itself to the olefinic carbon atom, which is removed from the cyano group of the nitrile, and the hydrogen atom the olefinic carbon atom adjacent to the cyano group.

The reaction proceeds according to the following equation: are phenylphosphorus dichloride or diphenyl phosphorus chloride.

Heterocyclic amines These are those six-membered, heterocyclic Amines with one or more heterocyclic rings that are only carbon and Contains nitrogen or only carbon, nitrogen and sulfur atoms in the ring and the ring atoms thereof optionally carry alkyl or aryl substituents. Examples for the alkyl and aryl substituents attached to the atoms of the heterocyclic rings can be bound are methyl, ethyl, Propyl, butyl, pentyl, Cyclohexyl, phenyl or tolyl groups. Typical heterocyclic amine catalysts are 4-ethylpyridine, γ-picoline-thiodiphenylamine or a polyalkylpyridine.

Diarylamines of the formula wherein R 'and R "are aryl radicals which need not be the same. Examples of the aryl groups which R' and R" can represent are phenyl, tolyl, naphthyl, anthryl or phenanthryl groups. Preference is given to using diarylamines which contain a phenyl radical, e.g. B. phenyl-a-naphthylamine or phenyl-ß-naphthylamine.

Organophosphonates of the formula where R ", R? Jl and R""are identical or different alkyl, cycloalkyl or aryl radicals. Examples of such radicals are methyl, ethyl, propyl, butyl, pentyl, cyclohexyl, phenyl The phosphonates preferably used are ethylphosphonic acid diethyl ester, butylphosphonic acid dibutyl ester or phenylphosphonic acid diphenyl ester.

Dialkylcyanamides of the formula where R 'and R "are alkyl radicals which need not be dissimilar. Examples of such radicals are methyl, ethyl, propyl, butyl or pentyl groups. The preferred dialkyl cyanamide catalysts are dimethyl cyanamide, diethyl cyanamide, dipropyl cyanamide or dibutyl cyanamide.

The aforementioned catalysts can be used in amounts of 0.2 to 10 parts by weight be used per 100 parts of the total weight of the starting substances.

The above-mentioned catalysts are preferably used in amounts of 0.3 to 3 parts by weight per 100 parts of the total weight of the acrylonitrile used and trichlorosilane are used.

The acrylonitrile and trichlorosilane used as the starting material can be used in amounts ranging from about 1/2 to 2 moles of nitrile per mole of silane can vary. The reactants are preferably used in equimolar amounts used. Amounts in which one of the starting substances is in excess of this Ratio present can also be used; but do not bring any advantage.

The temperatures used in carrying out the process are between 40 and 350 ° C. When carrying out the process in a pressure vessel a temperature in the range of about 125 to about 250 ° C is preferred. Among those Conditions are - a reaction time of about 2 to about 5 hours.

Temperatures of about 175 to about 300 ° C are preferred when the process is carried out in a fluidized bed in a closed system. In such a System in which a pressure of around atmospheric pressure up to 280kg / cm2 and higher prevails the required reaction time is only about 0.005 minutes.

After the reaction, the reaction mixture contains as the main product ß-cyanoethyltrichlorosilane and some unreacted acrylonitrile and trichlorosilane. The main product can be obtained by a distillation process that operates at reduced pressure is carried out, are separated.

Example 1 In a 50 ml steel pressure vessel 0.15 mol (7.9 g) acrylonitrile, 0.15 mol (20.3 g) trichlorosilane and 0.56 g (2 percent by weight) Diphenyl phosphorus chloride given. The container was sealed and for 2 hours heated to 200 ° C. Thereafter, the container was cooled to room temperature and the The reaction mixture is poured into a flask connected to a distillation column was. The contents of the flask became under reduced pressure. Boiling heated so as not to remove reacted starting material, and then the pressure gradually increased to 3 mm Hg decreased. The distillate was 13.2 g of β-cyanoethyltrichlorosilane at the boiling point 75 to 80 ° C / 3 mm Hg obtained. The yield was 46.8%.

Example 2 In a 50 mol steel pressure vessel 0.15 mole (7.9 g) of acrylonitrile, 0.15 mole (20.3 g of trichlorosilane and 0.56 g (2 percent by weight) Phenyl phosphorus dichloride given. The container was sealed and for 2 hours heated to 200 ° C. Thereafter, the container was cooled to Ranmtemperature and that Reaction mixture worked up as in - Example 1.

The distillate was 10.92 g-cyanoethyltrichlorosilane with a boiling point 75 to 80b C / 3-mm Hg obtained. The yield of B-cyanoethyltrichlorosilane was 38.9 %.

Example 3 In a 300 ml stainless steel pressure vessel Steel were 0.15 mole (7.9 g) acrylonitrile, 0.15 mole (20.3 g) trichlorosilane and Added 0.56 g (2 percent by weight) of 4ethylpyrdine. The container was sealed and heated to 200 ° C for 2 hours. After that, the container was brought to room temperature chilled and. its contents placed in a flask that, with a distillation column was connected. The contents of the flask were used to remove the unreacted The starting materials are heated to the boil and the pressure is then gradually reduced to 3 mm Hg. 11.46 g of XB-cyanoethyltrichlorosilane with a boiling point of 75 to 80 ° C./3 were used as the distillate mm Hg. The yield of β-cyanoethyltrichlorosilane was 40.6%.

Example 4 In a 300 ml pressure vessel - made of stainless steel Steel were 0.15 mol (7.9 g) acrylonitrile, 0.15 mol (20.3 g) trichlorosilane and 0, 56 g (2 percent by weight) of γ-picoline are given. Of the. Container was. locked and Heated to 200 ° C for 2 hours. -After that, the container was brought to room temperature cooled, its contents placed in a flask filled with a. Distillation column was connected, and the product was distilled according to the method described in Example 3. The distillate with a boiling point of 75 to 80 ° C / 3 mm Mg was 8; 88 g-cyanoethyltrichlorosilane inherited. The yield was 31.5%.

Example 5 In a 300 ml stainless steel pressure vessel Steel were 1.33 moles (70.6 g) acrylonitrile, 1.33 moles (180.1 g) trichlorosilane and Added 2.5 g (1.0 weight percent) thiodiphenylamine. The container was sealed and heated to 200 ° C. for 2 hours. After that, the container was brought to room temperature cooled and its contents placed in a flask connected to a distillation column was connected. The contents of the flask were determined according to the procedure given in Example 3 distilled. There were 63.2 g of ß-Cyanäthyltrichlorosilan from boiling point 75 to 80 ° C / 3 mm Hg obtained. The yield of β-cyanoethyltrichlorosilane was 25.2%.

Example 6 In a 50 mol steel pressure vessel 0.15 mol (7.9 g) acrylonitrile, 0.15 mol (20.3 g) trichlorosilane and 56 g (2 percent by weight) Phenyl-a-naphthylamine given. The container was sealed and for 2 hours heated to 200 ° C. The container was then cooled to room temperature, the product placed in a flask connected to a distillation column and after the method given in Example 3 distilled. As a distillate with the boiling point At 75 to 80 ° C / 3 mm Hg, 10.4 g of β-cyanoethyltrichlorosilane were obtained. The yield was 35.6%.

Example 7 In a 50 mol steel pressure vessel 0.15 mol (7.9 g) acrylonitrile, 0.15 mol (20.3 g) trichlorosilane and 0.56 g (2 percent by weight) Phenylphosphonic acid diphenyl ester given. The container was closed and 2 Heated to 200 ° C for hours. Thereafter, the container was cooled to room temperature; 23 g of the reaction mixture was removed therefrom and placed in a flask with a distillation column distilled in the manner indicated in Example 3. There were 14.35 g of β-cyanoethyltrichlorosilane with a boiling point of 75 to 80 ° C / 3 mm Hg. The yield was 50.7%.

Example 8 In a 50 mol steel pressure vessel 0.15 mol (7.9 g) acrylonitrile, 0.15 mol (20.3 g) trichlorosilane and 0.56 g (2 percent by weight) Given butylphosphonic acid dibutyl ester. The container was sealed and 2 hours heated to 200 ° C for a long time. Thereafter, the container was cooled to room temperature and 24.3 g of the reaction mixture removed therefrom were placed in a flask with a distillation column was connected. After the work-up described in Example 3 were 11.76 g of ß-Cyanäthyltrichlororsilan with a boiling point of 75 to as the distillate 800 C / 3 mm Hg obtained. The yield of β-cyanoethyltrichlorosilane was 41.60 / o.

Example 9 In a 50 mol steel pressure vessel 0.15 mole (7.9 g) acrylonitrile, 0.15 mole (20.3 g) Trichlorosilane and 56 g (2 percent by weight) ethylphosphonic acid diethyl ester given. The container was sealed and heated to 2000 C for 2 hours. Thereafter, the container was cooled to room temperature and 22.4 g of the removed therefrom Reaction mixture placed in a flask connected to a distillation column was, and distilled according to the procedure described in Example 3. As a distillate With a boiling point of 75 to 800 C / 3 mm Hg, 11.72 g of β-cyanoethyltrichlorosilane were obtained obtain. The amount obtained corresponded to a yield of 41.5%.

Example 10 In a 50 ml steel pressure vessel, 0.15 Moles (7.9 g) of acrylonitrile, 0.15 moles (20.3 g) of trichlorosilane and 0.56 g (2 percent by weight) Given diethyl cyanamide. The container was sealed and left open for 2 hours Heated to 250 ° C. The container was then cooled to room temperature and the reaction mixture was cooled placed in a flask connected to a distillation column. To the work-up described in Example 3 were 12,17gß-Cyanäthyltrichlorosilan with a boiling point of 75 to 80 ° C / 3 mm Hg. The yield was 43.1%.

Claims (2)

PATENT CLAIMS: 1. Process for the preparation of ß-cyanoethyltrichlorosilane by reacting trichlorosilane with acrylonitrile at an elevated temperature, characterized in that the reaction is carried out at a temperature between 40 and 350 ° C in the presence of a catalyst which is either an organophosphorus halide of the formula Ry ' -PX (3-y) where R 'is a preferably aromatic hydrocarbon radical, X is a halogen atom and y is the number 1 or 2, or a heterocyclic amine with one or more heterocyclic rings consisting only of carbon and nitrogen or only of carbon -, nitrogen and sulfur atoms and their ring atoms optionally carry alkyl or aryl substituents, or a diarylamine or an organophosphonate of the formula where R ", R"'and R "1 represent identical or different alkyl, cycloalkyl or aryl radicals, or is a dialkylcyanamide. 2. The method according to claim 1, characterized in that as Catalyst uses a diarylamine which contains at least one phenyl group. References considered: U.S. Patent No. 2,721 873.