JPS6121477B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for stabilizing trimethoxysila. Specifically, the present invention relates to a method for stabilizing trimethoxysilane in a reaction mixture containing trimethoxysilane obtained by reacting silicon and methyl alcohol in the presence of a copper catalyst. Conventionally, trimethoxysilane is produced by reacting silicon metal and methyl alcohol at 100 to 300°C in the presence of a copper catalyst, distilling the resulting trimethoxysilane out of the system together with unreacted methyl alcohol, and then A method of separating trimexysilane by distillation from a distillation reaction mixture is known. However, in the above method, when storing the distillation reaction mixture or separating trimethoxysilane from the distillation reaction mixture by distillation, trimethoxysilane in the distillation reaction mixture and unreacted methanol react to form tetramethoxysilane. is produced, and as a result, there is a problem that the amount of trimethoxysila produced decreases. Therefore, the present inventors investigated a method for stabilizing trimethoxysilane in the above reaction mixture, and found that by allowing a specific amino acid to exist in the reaction mixture, the reaction between trimethoxysilane and methanol in the main reaction could be suppressed. It has been discovered that trimethoxysilane can be effectively suppressed and significantly stabilized, leading to the present invention. That is, the object of the present invention is to
The purpose is to stabilize trimethoxysilane in the reaction mixture obtained by reacting silicon and methyl alcohol;
general formula

This is achieved by the presence of an amino acid represented by the formula: (R represents hydrogen, an alkyl group having 1 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms). Next, the present invention will be explained in detail. In the method of the present invention, trimethoxysilane is produced by reacting silicon and methyl alcohol in the presence of a copper catalyst in a gas phase system or a liquid phase system. As silicon, silicon metal having a purity of 88 to 99.9% is usually ground to an average particle size of 200 microns or less, preferably 100 microns or less. As the copper catalyst, a copper catalyst such as metallic copper or a copper compound is preferably used. As a copper compound,
halides, carboxylates, chelate compounds,
Various oxides can be used, and specifically, for example, cuprous chloride, cupric chloride, cuprous oxalide, cupric oxalide, cuprous iodide,
Examples include cupric iodide, copper formate, copper acetylacetonate, cuprous acetate, cupric acetate, cuprous oxide, and the like. The amount of copper catalyst to be used is selected from the range of 0.0001 to 0.5 times the mole of silicon metal. When the reaction is carried out in a liquid phase system, a solvent is used in an amount of 1 ml to 10 ml per gram of silicon metal. Examples of solvents include alkylbenzenes such as cumene, n-butylbenzene, cymene, hexamethylbenzene, triethylbenzene, octylbenzene, dodecylbenzene, and didodecylbenzene, naphthalene, methylnaphthalene, propylnaphthalene, dipropylnaphthalene, and tripropyl. Alkylnaphthalenes such as naphthalene, or
Aliphatic hydrocarbons such as n-decane, dodecane, tetradecane, octadecane, and liquid paraffin, and arylmethanes such as diphenylmethane, triphenylmethane, ditolylmethane, benzyltoluene, dibenzyltoluene, and dibenzylxylene are used. The amount of methyl alcohol to be used is selected from the range of 0.1 to 100 times, preferably 1 to 50 times, per mole of silicon metal. The reaction temperature is appropriately selected within the range of 100 to 300°C. The reaction pressure may be reduced pressure, normal pressure, or increased pressure.
Preferably, it is selected from 500 mmHg to 2000 mmHg. Trimethoxysilane is distilled out of the system after the reaction is completed or continuously during the reaction. The resulting distillation reaction mixture contains, in addition to trimethoxysilane, monomethoxysilane, dimethoxysilane, tetramethoxysilane, unreacted methyl alcohol, and the like. In the method of the present invention, the general formula

It is necessary for the amino acid represented by the formula to be present. In the above general formula, R represents hydrogen, an alkyl group having 1 to 10 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms. Specifically, examples of alkyl groups include methyl, ethyl, propyl, butyl, and the like, and examples of aralkyl groups include benzyl, phenylethyl, and the like. Specific examples of amino acids used in the present invention include glycine, alanine, valine, leucine, isoleucine, and phenylalanine. The amount of amino acid added is based on the reaction mixture.
Range of 0.0001 to 50% by weight, preferably 0.001 to 50% by weight
It is 1% by weight. In order to make the above amino acid exist in a reaction mixture containing trimethoxysilane, it is sufficient to add the above amino acid to the reaction mixture distilled out after the trimethoxysilane production reaction. Alternatively, the above-mentioned amino acid may be added to the reaction mixture after the trimethoxysilane production reaction is completed and before the reaction mixture containing trimethoxysilane is distilled off. As described above in detail, according to the present invention, trimethoxysilane in a reaction mixture obtained from silicon and methyl alcohol can be effectively stabilized. Next, the present invention will be specifically explained using Examples, but the present invention is not limited to the following Examples unless it exceeds the gist thereof. Example 1 Silicon metal powder (purity
98%), 5.0 g of cuprous chloride, and 200 c.c. of dodecylbenzene. A condenser was attached to the outlet of the distillation tube to collect trimethoxysilane produced and unreacted methyl alcohol, etc., which were distilled out. The reactor was heated, and when the bath temperature reached 200°C, introduction of methyl alcohol was started from the introduction tube. The introduction rate of methyl alcohol is 75c.c./during the reaction.
It was kept constant over time. The total amount of the distilled reaction mixture 7.5 hours after the start of introduction was 544.6 g. The amount of ingredients in the mixture is methyl alcohol 194.3
g, trimethoxysilane 286.9g, tetramethoxysilane 42.4g, etc. When 1/10 of this reaction mixture was taken, 0.50 g of glycine was added thereto, and the mixture was left to stand at room temperature for 40 hours, the remaining amount of trimethoxysilane in the reaction mixture was 27.2 g, and the residual rate was 94.8. It was %. Here, the residual rate is the ratio (% by weight) of the amount of trimethoxysilane after 40 hours to the amount of trimethoxysilane immediately after the reaction. For comparison, when the distillation reaction mixture was allowed to stand for 40 hours without adding glycine, the residual rate of trimethoxysilane was 50.1%. Example 2 Add 0.51 alanine instead of glycine as an additive
When the distillation reaction mixture was left to stand for 40 hours in the same manner as in Example 1 except that g was added, the residual rate of trimethoxysilane was 96.0%.

Claims (1)

[Claims] 1. In a reaction mixture containing trimethoxysilane obtained by reacting silicon and methyl alcohol using a copper catalyst, a compound having the general formula [Formula] (R is hydrogen, and has 1 to 20 carbon atoms) Alkyl group or carbon number 7
1. A method for stabilizing trimethoxysila, characterized in that an amino acid represented by ~20 aralkyl groups is present.