JPS6323196B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for producing trialkoxysilane, and particularly to a method for producing trialkoxysilane, in particular a method for producing trialkoxysilane by reacting a trialkoxysilane with an alkyl alcohol in an alkoxysilane-containing reaction product solution obtained by the reaction of silicon and an alkyl alcohol. The present invention relates to a method for obtaining trialkoxysilane in high yield by preventing a decrease in the yield of alkoxysilane. (Prior art) Regarding the manufacturing method of trialkoxysilane, a method is known in which silicon and alkyl alcohol are reacted in the presence of a copper catalyst, but this method has a low reaction rate of alcohol, so distillate The resulting reaction product solution containing various alkoxysilanes contains a relatively large amount of alkyl alcohol, and this is due to a dehydrogenation reaction between the residual alcohol and trialkoxysilane during storage or purification. It has the disadvantage of converting into tetraalkoxysilane. Therefore, for the production of trialkoxysilane by this method, the general formula

[Formula] A method in which an amino acid represented by (R is a hydrogen atom, an alkyl group, or an aralkyl group) is present (see JP-A-55-72197), a method in which a trivalent organic phosphorus compound is present (JP-A-55-72197), -72198), and adding amines to adjust the pH to 2.0 to 7.0 (see JP-A-57-118592), but these stabilizers are based on trialkoxysilane and alkyl alcohol. The disadvantage is that the effect of suppressing the reaction with silane is not necessarily good, and trialkoxysilane cannot be obtained in high yield. (Structure of the Invention) The present invention relates to a method for producing trialkoxysilane that solves these disadvantages, and this invention involves producing trialkoxysilane obtained by reacting silicon and alkyl alcohol in the presence of a copper catalyst. It is characterized by the presence of epoxides in the reaction product liquid. That is, the present inventors have conducted various studies on methods for preventing the reaction between trialkoxysilane and alkyl alcohol in a reaction product solution containing trialkoxysilane obtained from the reaction of silicon and alkyl alcohol. When epoxides are added to a reaction product solution containing They found that it was possible to obtain the epoxide in high yield, and conducted research on the type of epoxide liquid, the amount added, etc., and completed the present invention. The method of the present invention is carried out in a known manner by first reacting silicon with an alkyl alcohol in the presence of a copper catalyst to obtain an alkoxysilane mixture containing trialkoxysilane. Both silicon and alkyl alcohol in this case may be commercially available products, and this silicon is made by grinding metallic silicon with a purity of 88 to 99.9% to a particle size of 100μ or less, and the alkyl alcohol is methyl alcohol, ethyl alcohol, etc. It is preferable to use an alkyl group having 1 to 5 carbon atoms, such as alcohol, propyl alcohol, butyl alcohol, and the like. In addition, this copper catalyst can be metallic copper or cuprous chloride,
Cupric chloride, cuprous bromide, cupric bromide, cuprous iodide, cupric iodide, copper formate, copper acetylacetate, cuprous acetate, cupric acetate, cuprous oxide A copper compound selected from the following may be used in an amount of 0.001 to 0.5 times the mole of silicon. In order to increase the yield of trialkoxysilane from this reaction, this reaction is preferably carried out in the presence of a solvent.
Dodecylbenzene, triphenyl hydroxide, dialkylbenzene, diphenyl ether, etc. may be used as necessary. This reaction can be carried out at 100 to 300°C under reduced pressure, normal pressure, or increased pressure. According to this, trimethoxysilane can be obtained as a distillate together with other alkoxysilanes that are simultaneously produced. In the method of the present invention, epoxides are added in order to prevent transition of trialkoxysilane to tetraalkoxysilane due to reaction with alkyl alcohol. This epoxide may be added to this reaction system in advance, or may be added to the distillate obtained from the above reaction. These epoxides include butylene oxide, epoxypentane, hexane oxide, pentene oxide, styrene oxide, 1,2
-Epoxy-3-phenylpropane, methyl glycidyl ether, ethyl glycidyl ether, phenyl glycidyl ether, ethylene glycol glycidyl ether, diglycidyl ether, cyclopentene oxide, cyclohexene oxide, cyclohexadiene dioxide, etc. are exemplified, but this reaction Since the produced liquid is then treated by distillation etc. for the purpose of separating and purifying trialkoxysilane, etc., the epoxides should also have a boiling point higher than that of trialkoxysilane, etc. From this point of view, phenyl glycidyl ether, Preferably, it is selected from ethylene glycol diglycidyl ether and cyclohexene oxide. The amount of epoxide added may be determined depending on the amount of trialkoxysilane present in the reaction product solution, but it is usually in the range of 0.01 to 10% by weight based on the reaction product solution.
Preferably it is 0.1 to 5% by weight. Next, examples of the method of the present invention will be given. Examples 1 to 3, Comparative Examples 1 to 4 A 500 ml flask with an alcohol inlet tube, a thermometer, a stirrer and a product distillation tube was charged with a purity of 98%.
100 g of silicon powder, 5 g of cuprous chloride, and 200 ml of diphenyl ether were charged, and a cooler was attached to the outlet of the product distillation pipe so that the alkoxysilane produced and unreacted alcohol could be condensed and collected. did. Next, warm this flask until the internal liquid temperature reaches 200℃.
When the reaction temperature reached 198 ml, methyl alcohol was introduced from the alcohol inlet tube at a rate of 75 ml/hour.
When the reaction was carried out at ~202°C for 5 hours, 320.0 g of distillate was obtained, but gas chromatographic analysis showed that this was 146.4 g (46.1 wt%) of trimethoxysilane and 16.5 g (50 wt%) of tetramethoxysilane. )
It included: Next, 7 samples were prepared by taking 10 g of this distillate, and 0.1 g of phenyl glycidyl ether, ethylene glycol diglycidyl ether, and cyclohexene oxide were added to these three samples and compared with the other three samples. For this reason, 0.1 g of glycine, triphenoxylin, and hexamethylenetetramine were added, and the remaining one was left unadded for 72 hours at room temperature. Gas chromatography analysis was performed on these. The methoxysilane concentration and its residual rate were as shown in Table 1.

【table】

[Table] Example 4, Comparative Example 5 1 g of ethylene glycol diglycidyl ether was added to 100 g of the distillate obtained in Example 1, and this was added to a 200 ml glass tube equipped with a 20 mmφ, 50 cm distillation column filled with a glass coil pack. The distillate was placed in a flask and distilled for 5 hours, and after the completion of the distillation, gas chromatography analysis of the distillate and the residue from the pot revealed that the amount of trimethoxysilane obtained was 44.4 g, with a residual rate of 97.0%. However, for comparison, gas chromatographic analysis of the distillate obtained by the same treatment as above without adding any epoxides revealed that the amount of trimethoxysilane was 25.2 g and the residual rate was 55.1. It was %.

Claims (1)

[Claims] 1. Production of trialkoxysilane, characterized in that epoxides are present in a reaction product solution containing trialkoxysilane obtained by reacting silicon and alkyl alcohol in the presence of a copper catalyst. Method. 2 Epoxides include phenyl glycidyl ether, ethylene glycol diglycidyl ether,
The method for producing a trialkoxysilane according to claim 1, wherein the trialkoxysilane is selected from cyclohexene oxide. 3. The method for producing trialkoxysilane according to claim 1 or 2, wherein the alkyl alcohol is methyl alcohol.