KR100808258B1 - Preparation method of tetraalkoxysilane from silica minerals - Google Patents

Abstract

A method for preparing tetraalkoxysilane is provided to be able to increase the yield of the tetraalkoxysilane by increasing the conversion rate of a silica into alkoxy silane through use of amorphous silica as silicone and optimization of a reactor where the silicone and triethanol amine efficiently reacts. A method for preparing tetraalkoxysilane comprises the steps of: (a) after dissolving tris silatranyl oxyethylamine generated by reacting a silica obtained by purifying at least one selected from the group consisting of silica minerals, ashes, fly ashes and wastes of mine, NaOH and triethanolamine under nitrogen atmosphere in methanol, injecting anhydrous hydrogen chloride gas into the methanol to prepare a methoxy silatrane; and (b) reacting the methoxy silatrane with ethanol to extract the tetraalkoxysilane.

Description

Preparation Method of Tetraalkoxysilane from Silica Minerals

1 is an infrared spectroscopy spectrum of tetramethoxysilane according to the present invention.

2 is a gas chromatograph pattern diagram of tetramethoxysilane according to the present invention.

The present invention relates to a method for preparing tetraraalkoxysilane, and more particularly, to a tetraalkoxysilane prepared by reacting a silica mineral with a triethanolamine under a sodium hydroxide catalyst and then reacting with a lower alcohol in an acidic atmosphere. It is about a method.

Alkoxy silanes, such as tetraethyl orthosilicate (TEOS) and tetramethoxy orthosilicate (TEOS), are widely used as sol-gel optical fibers, starting materials for the synthesis of ceramics, and materials for forming semiconductor insulating films. .

In 1846, Ebelmen synthesized tetraethoxysilane from silicon tetrachloride and ethanol and reported the first alkoxy silane synthesis reaction. Since 1920, many studies on the reaction mechanism and physical properties of various metal alkoxides including alkoxy silane have been conducted. . Synthesis of the alkoxy silane is widely known in various ways such as reaction of silicon chloride and alcohol, reaction of metal silicon and alcohol, reaction of silicon hydroxide or oxide and alcohol, exchange of alcohol, and the like.

At present, the most widely used method for the production of alkoxysilanes is a method for preparing by reacting tetrachloride silane with an alcohol. However, the method is a by-product of the hydrogen chloride is generated by the corrosion of the manufacturing apparatus, a device of a special material to prevent this is required, there is a disadvantage that takes a lot of expense in the removal and disposal of hydrogen chloride.

In order to overcome the above disadvantages, a method of preparing a tetraalkoxysilane by reacting a metal silicon powder and a lower alcohol using a copper catalyst has been proposed, but in this reaction, not only the tetraalkoxysilane which is a target compound, but also a trialkoxysilane and Other silicone derivatives are produced together, and a high molecular weight and high boiling point disilane compound is also produced. And the reaction of silicon metal or oxide with alcohol needs to optimize these factors to obtain high temperature, high pressure, large surface area of metal and substantial fast reaction rate. In addition, the silicon alkoxide may be prepared by the electrolytic method, but this method requires a lot of investment cost and operation cost, and there is a problem that the separation of the product is difficult.

In order to improve the production efficiency of such tetraalkoxysilane, a method using metal copper or a compound thereof has already been disclosed. For example, US Pat. Nos. 4,289,889 and 4,762,939 use a copper catalyst and a special type of solvent to react in a liquid phase, or US Pat. No. 4,447,632 uses alkali metal carbonate as a high pressure reaction catalyst. Or US Pat. Nos. 4,211,717 and 4,752,647 disclose methods for reacting in a liquid phase using an alkali metal or alkali metal alkoxide as a catalyst and using a special type of solvent.

The method for producing tetraalkoxysilanes by the direct synthesis method has a problem such that a high-pressure reaction vessel is required under high pressure, and various alkoxysilanes such as trialkoxysilanes are simultaneously generated and a continuous process is impossible. As the silicon metal, high purity metal silicon is used. A well-known technique for improving the problem of the simultaneous generation of such various alkoxysilanes is Korean Patent Application No. 10-2006-0005031, which is a metal silicon (Silicon) separated and recovered from waste in the presence of a high boiling alkali alkoxide catalyst The present invention relates to a method for producing tetraalkoxysilane by reacting a low alcohol such as methanol and ethanol at 180-210 ° C.

As described above, the synthesis of the alkoxy silane can be performed by various methods such as 1) reaction of silicon chloride with alcohol, 2) reaction of metal silicon with alcohol, 3) reaction of silicon hydroxide or oxide with alcohol, and 4) exchange of alcohol. This is known, but little is known about the production of alkoxy silanes from silica, which is a natural mineral. When the silica mineral is directly used as a raw material for the production of the alkoxy silane in the raw material for producing the silicon compound, more energy can be saved than using the silicon metal, which is an economical method.

The present invention has been made in order to solve the various problems of the prior art as described above, the object of the present invention is a silica mineral as a raw material, silicon is used as a sample of amorphous silica, the silicon and triethanolamine reacts efficiently The production of tetraalkoxysilanes by which the reaction rate of alkoxysilanes can be increased by adopting a catalyst that can optimize the reaction apparatus to improve the conversion rate of the raw material silica to alkoxysilane and ultimately increase the yield of tetraalkoxysilane. It provides a way.

Tetraalkoxysilane production method according to the present invention for achieving the above object is a trissilatraniloxyethylamine produced by the reaction of silica and silica and triethanolamine purified silica minerals with ethanol or methanol in an acid catalyst The tetraalkoxysilane is extracted by reacting with any one selected from the same low boiling alcohol.

Here, the silica is preferably any one selected from the group consisting of silica mineral, volcanic ash, coal ash, mine waste and industrial by-products.

In addition, the acid catalyst is preferably any one selected from the group consisting of anhydrous acid, such as anhydrous hydrogen chloride, fuming sulfuric acid.

Also. The lower alcohol is preferably any one selected from the group consisting of methanol, ethanol, propanol, isopropanol, butanol, isobutanol, secondary butanol and tertiary butanol.

The present invention for achieving the above technical problem, a step of synthesizing tetraalkoxysilane by the reaction of silica and triethanolamine produced in Korea, and the reaction of the reactant with alcohol of ethanol or methanol under acidic conditions Characterized by going through a series of steps consisting of.

The features and advantages of the present invention will become more apparent from the following detailed description based on the accompanying drawings. Prior to this, the terms or words used in the present specification and claims are defined in the technical spirit of the present invention on the basis of the principle that the inventor can appropriately define the concept of the term in order to explain his invention in the best way. It must be interpreted to mean meanings and concepts.

Hereinafter, the manufacturing method of the tetraalkoxysilane which concerns on the Example of this invention is demonstrated in detail.

The method for preparing tetraalkoxysilane according to the present invention is that the synthesis of alkoxysilane is a step of reacting silica and triethanolamine produced domestically and tetraalkoxysilane by reaction of the reactant with alcohol of ethanol or methanol under acidic conditions. It consists of the steps of synthesizing. Hereinafter, the present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited to the following examples.

<Example 1>

Silica, triethanolamine, and sodium hydroxide (NaOH) are placed in a 500 ml three-necked flask, and the mixture is stirred at 210 ° C. under a nitrogen atmosphere. At this time, the silica has a weight of 36.0g, the average particle diameter is 20μm, the trimethanolamine has a weight of 109.2g, the molecular weight of 0.8mol, and the sodium hydroxide weight of 0.8g and 0.02mol of a gas molecule of 0.02mol. Do.

Thereafter, after reacting the mixture for 4 hours, excess triethanolamine of the mixture is removed by vacuum distillation. The vacuum distilled reactant was dissolved in 200 ml of dry acetonitrile to remove unreacted silica by filtration. This was distilled off again to remove acetonitrile and dried in vacuo at 150 ° C. to obtain 101.2 g of trissilatranyloxyethylamine (Tris (silatranyloxyethyl) amine). Silica was converted to trissilatranyloxyethylamine, a silicon intermediate, as shown in FIG.

After dissolving trissilatranyloxyethylamine obtained through the above process with 20 ml of dried methanol, anhydrous hydrogen chloride gas is blown into the reaction solution for 2 hours. At this time, the weight of trissilatranyloxyethylamine is 20.0 g, the basic molecular number is 0.0765 mol, the amount of anhydrous hydrogen chloride gas is added is 1030ml and the basic molecular number is preferably 0.0046mmol. After stirring the mixture for about 2 hours, the solvent was distilled off, and this was recrystallized from dry diethyl ether to obtain 12 g of colorless crystals of methoxysilatrane.

The ethoxysilatran obtained by recrystallization from diethyl ether is dissolved in 100 ml of dry ethanol. At this time, it is preferable that the quantity of ethoxy silatran is 20g. Anhydrous hydrogen chloride gas was blown into the ethanol in which ethoxysilatran was dissolved at room temperature for 2 hours, and no more hydrogen chloride gas was blown to absorb the gas. Thereafter, 100 ml of dry diethyl ether was added to the reaction mixture, and the mixture was mixed well. The solid material was filtered off, and the remaining liquid material was distilled to obtain 15.9 g of tetraethoxysilane.

<Example 2>

In the description of the second embodiment, the same parts as in the first embodiment will be omitted. In Example 2, after dissolving trissilatranyloxyethylamine obtained through the same process as in Example 1 with 100 ml of dried ethanol, fuming sulfuric acid was added dropwise. At this time, the amount of trisilalanilyloxyethylamine is 33.5g, fuming sulfuric acid is the weight of 7.55g, the base molecular number is 0.077mol, it is preferable that fuming sulfuric acid has the weight of 7.55g and the base molecular number of 0.077mol. . Thereafter, the mixture was stirred for about 1 hour by reacting a mixture of trissilatranyloxyethylamine, dried ethanol and fuming sulfuric acid, and then the solvent was distilled off. The remaining material was recrystallized from ethanol / diethyl ether, and filtered to give 24.0 g of ethoxysilatranes, colorless needle-shaped crystals.

After dissolving the ethoxysilatran obtained through the above method in 100 ml of dry methanol, the anhydrous hydrogen chloride gas is blown for 2 hours at room temperature until the hydrogen chloride gas is not absorbed even if the hydrogen chloride gas is blown. At this time, the weight of the ethoxysilatran is preferably 15.6g, the number of basic molecules is 0.072mol. The reaction product was mixed well by adding about 100 ml of dry diethyl ether, and then the solid material was filtered off. The remaining liquid material was distilled off to obtain 8.9 g of tetramethoxysilane. The trissilatraniloxyethylamine, a silica and silicon intermediate, was converted to tetramethoxysilane, a silicon intermediate, as shown in FIG. In addition, Figure 2 shows the gas chromatograph profile of the tetramethoxysilane prepared in Example 2. A column of OV-1 series and a thermal conductivity detector (TCD) were used, and the retention time was 1.39 minutes.

What has been described above is only one embodiment for carrying out the present invention, and the present invention is not limited to the above-described embodiment, and the present invention is made without departing from the gist of the present invention as claimed in the following claims. Anyone with ordinary knowledge in this field will have the technical spirit of the present invention to the extent that various modifications can be made.

As described above, according to the method for producing tetraalkoxysilane according to the present invention, the silica mineral is made of silicon using amorphous silica as a sample, and the raw material is optimized by optimizing a reaction apparatus in which the silicon and triethanolamine can be efficiently reacted. The conversion of phosphorus silica to alkoxysilanes can be increased, ultimately increasing the yield for tetraalkoxysilanes. That is, when preparing the alkoxysilane from the silica purified silica mineral can be obtained a useful effect that can greatly increase the yield of tetraalkoxysilane

Claims (4)

Silica produced by purifying any one of silica minerals, volcanic ash, coal ash and mine waste, and trissilatranyloxyethylamine produced by reacting sodium hydroxide and triethanolamine in a nitrogen atmosphere in methanol, and then anhydrous hydrogen chloride gas A method for producing tetraalkoxysilane, which is injected into methanol to produce methoxysilane, and the methoxysilane is reacted with ethanol to extract tetraalkoxysilane. delete delete delete

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