JPH0688770B2 - Monosilane manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing monosilane from an alkoxysilane as a raw material.

[Conventional technology]

Monosilane is used as a high-purity silicon raw material for semiconductors, as well as amorphous silicon photoconductors, solar cells,
It is widely used as a raw material for New Ceramics materials.

Many proposals have hitherto been made regarding a method for producing monosilane. Japanese Examined Patent Publication No. 51-20040 describes a method of disproportionating triethoxysilane using sodium ethoxide as a catalyst, as one of the most effective methods for producing monosilane.

[Problems to be Solved by the Invention] Although this method has excellent characteristics such as extremely high catalytic efficiency, since the catalytic reaction is carried out in a liquid phase medium,
There is a problem that the catalyst is dissolved in a by-product substance (tetraethoxysilane etc.), and it is not always easy to separate the catalyst and the by-product substance. As is clear from the above formula, this reaction produces a large amount of by-product substances, but this by-product substance is useful as a raw material for various silicon compounds, for example, a raw material for high-purity silicon. is necessary.

An object of the present invention is to provide a method for producing monosilane, which can efficiently produce monosilane from a raw material alkoxysilane and can easily separate a catalyst from a reaction product.

[Means for solving problems]

In view of the above-mentioned drawbacks, the present inventors have studied a catalyst having a high catalyst efficiency and an easy separation operation from a reaction product, and as a result, a certain kind of solid catalyst is found to meet this purpose. Heading The invention has been reached.

That is, the present invention disproportionates an alkoxysilane represented by the general formula (I) in the presence of a catalyst composed of an anion exchange resin to produce H _n Si (OR) _4-n (I) (wherein R Represents an alkyl group having 1 to 6 carbon atoms, and n represents 1, 2 or 3).

The present invention will be described in detail below.

Alkoxysilanes, which are the raw materials used in the present invention, are, for example, JP-A Nos. 54-163529 and 55-7689.
It is easily prepared by the method described in 1.

The disproportionation reaction in the method of the present invention is carried out using an anion exchange resin as a catalyst.

The anion exchange resin referred to herein is a polymer substrate polymerized in a three-dimensional manner, with a primary to tertiary amine or 4 as an exchange group.
A resin having a quaternary ammonium group bonded thereto, and a typical polymer substrate is a copolymer of styrene and divinylbenzene.

Ion-exchange resins are classified into low-crosslinking resins having a crosslinking degree of 8% or less and high-crosslinking resins having a crosslinking degree of more than 8%, depending on the crosslinking degree of the copolymer, and any of them can be used in the present invention. Further, structurally, depending on the porosity, gel, porous,
Although classified into a high-porous shape, any of them can be used in the present invention. The anion exchange resin that is generally available is a chemically stable Cl salt (RN-Cl) type, and when used normally, an OH salt (RN
・ OH) form, but in the method of the present invention, even in the Cl salt form,
OH salt form can be used.

Specific examples of commercially available anion exchange resins include SA-10A, HPA-25, PA-306, W of DiAiON manufactured and sold by Mitsubishi Kasei.
Examples include A-20 and WA-30.

The amount of the anion exchange resin used as a catalyst can achieve its original purpose by 0.01% by weight or more with respect to the raw material alkoxysilane, but a condition of 0.1 to 200% by weight is usually adopted.

The reaction can be carried out either in a suspended batch system or a fixed bed flow system. In particular, since it can be carried out without any restriction on the material of the apparatus, a suitable reaction type can be freely selected.

The reaction can achieve the purpose sufficiently even if it is carried out at normal pressure and room temperature, but it is generally more preferable to carry out the reaction at normal pressure and under heating. The process according to the invention is less temperature-dependent, but a particularly preferred temperature is between 50 ° and 80 ° C.

The reaction pressure may be any pressure from reduced pressure to increased pressure. However, when the product monosilane comes into contact with air, it is instantly ignited, and the normal pressure condition is excellent in operability.

The raw material alkoxysilane in the present invention may be a single composition or a mixture. On the other hand, tetramethoxysilane, which is one of the disproportionation reaction products, and other substances such as saturated aliphatic hydrocarbons such as hexane and heptane, and alicyclic saturated hydrocarbons such as cyclohexane may be used together as a solvent. I can.

The reaction is usually carried out under an inert gas atmosphere of nitrogen or argon. In particular, the use of nitrogen is suitable for condensing and collecting monosilane.

Next, the method of the present invention will be described more specifically by way of examples, but the present invention is not limited to the following examples unless it exceeds the gist.

〔Example〕

Example 1 A pressure-resistant glass autoclave having an internal volume of 100 ml, equipped with a stirring blade, a nitrogen gas introduction pipe, a gas discharge pipe with a cooling pipe, and a liquid charging pipe, was previously dried as a catalyst in a nitrogen stream under heating and manufactured by Mitsubishi Kasei 3.5 g of DiAiON-WA-30 anion exchange resin was charged, and the inside of the autoclave system was sufficiently replaced with nitrogen. Thereafter, 0.2 mole of trimethoxysilane was added from a liquid charging tube at room temperature and stirring was started.

The reaction occurs at room temperature from the time when the catalyst and trimethoxysilane come into contact with each other, monosilane is produced, and then heated to 70 ° C,
It was carried out for 1 hour until monosilane was not produced. The produced monosilane was quantified by gas chromatography over time. As a result, the conversion of trimethoxysilane was 97.5mole.
%, Monosilane formation was 0.0487 mole.

After the reaction, the reaction product was passed and the catalyst was separated. The catalyst is insoluble in the raw materials and reaction products, and can be easily separated.

Examples 2 to 3 Table 2 shows the results obtained by changing the type of anion exchange resin (all manufactured by Mitsubishi Kasei Co., Ltd.), the amount and the reaction time by the method used in Example 1. Table 1 shows the physical properties of the anion exchange resin used as a catalyst.

Each anion exchange resin used was insoluble in the raw material and the reaction product, and the catalyst could be easily separated by passing the reaction product.

[Effect] According to the method of the present invention, monosilane can be easily obtained from alkoxysilane as described above. Moreover, the catalyst used in the present invention is substantially insoluble in the reaction product,
Separation from the reaction product is extremely easy. Reaction products (by-products) are useful as raw materials for various silicon products, for example, raw materials for high-purity silicon used for applications such as optical fibers, IC sealants, IC devices, photomasks, etc. Easy is industrially significant.

Claims (1)

[Claims] 1. An alkoxysilane represented by general formula (I) in the presence of a catalyst, H _n Si (OR) _4-n (I) (wherein R is an alkyl group having 1 to 6 carbon atoms, n represents 1, 2 or 3.) A process for producing monosilane by disproportionation, which comprises using an anion exchange resin as a catalyst.