JP2727480B2 - Method for producing trialkoxysilane - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing trialkoxysilane, and more particularly to a method for producing trialkoxysilane by reacting silicon metal and an alcohol in the presence of a catalyst.

[0002]

2. Description of the Related Art Trialkoxysilanes have highly reactive silicon-hydrogen bonds and can be easily added to various olefins or acetylenes, so that compounds having various functions, such as silane coupling agents, can be produced. It is a useful compound as a raw material.

Conventionally, a method for producing an alkoxysilane is as follows: (1) A mixture of 90% metallic silicon and 10% copper is heated at 1050 ° C. for 2 hours in a stream of hydrogen in the presence of a contact body obtained by heating for 2 hours. Of tetramethoxysilane by reacting water and methanol in the gas phase (Journal
Of American Chemical Society (JAC
S.), Vol. 70, pp. 2170-2171, 1948), and (2) trialkoxysilane in the gas phase by blowing an alkyl alcohol vapor into a fluidized bed formed of finely ground silicon and a catalyst. Many methods are known, including a method for producing dialkoxysilane (Japanese Patent Publication No. 37-17967) and a method for producing (3) methoxysilane using a reaction solvent mainly containing dodecylbenzene (Japanese Patent Application Laid-Open No. 55-76891). Had been.

In recent years, it has been found that in a method for directly synthesizing trimethoxysilane in the gas phase from metallic silicon and methanol, the use of copper chloride as a catalyst has high reactivity and selectivity to trimethoxysilane ( JP-A-3-4439
No. 3). This is an excellent method.

[0005]

However, this method has a disadvantage that chlorine compounds generated due to chlorine in the catalyst are mixed into the product. In particular, when trialkoxysilane is used as a raw material for producing a silane coupling agent, a dechlorination treatment is required. Further, the chlorine compound may cause corrosion of equipment used for the reaction.

[0006] As a catalyst for this reaction, a compound which can be substantially used instead of copper chloride has not been found yet.

Accordingly, an object of the present invention is to provide a method for producing trialkoxysilane using a catalyst having high activity and generating no chlorine compound.

[0008]

Means for Solving the Problems The present inventors have conducted intensive studies on a method for producing trialkoxysilane, and as a result, it has been found that when a copper alkoxide is used as a catalyst, a high activity equivalent to or higher than that of copper chloride can be obtained. The present invention was found to be possible and no generation of chlorine compounds was observed, and the present invention was achieved.

That is, the present invention provides a method for producing trialkoxysilane by reacting metal silicon and an alcohol in the presence of a catalyst, wherein a copper alkoxide is used as the catalyst. is there.

The alcohol used in the present invention is preferably a lower alkyl alcohol, particularly preferably methanol or ethanol. The alcohol is supplied preferably at 0.1 to 20 mol / hour, more preferably at 0.5 to 5 mol / hour, per 1 mol of metal silicon.

In the present invention, copper alkoxide is used as a catalyst when silicon metal is reacted with the above alcohol. The copper alkoxide is preferably of the formula Cu
(OR) ₂ (where R represents an alkyl group having 1 to 10 carbon atoms). The alkyl group for R may be linear or branched. Examples of such an alkyl group include a methyl group,
Ethyl, propyl, butyl, isobutyl, sec-
Butyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, octyl, nonyl,
Decyl group and the like. The copper alkoxide catalyst is preferably used in an amount of 0.001 to 0.1 mol, more preferably 0.005 to 0.05 mol, per 1 mol of metal silicon.

In the method of the present invention, the reaction can be carried out in the gas phase or in the liquid phase. When it is performed in the gas phase, for example, it is performed as follows. First, a touch body is prepared. As a method, for example, physically mixing metal silicon and copper alkoxide powder or dissolving copper alkoxide in a ketone solvent such as dimethyl ketone,
A method of adding metal silicon powder to the solution and then evaporating to dryness under reduced pressure can be mentioned. The thus-obtained touch body usually flows an inert gas such as a helium gas or a hydrogen gas at a rate of several liters / hour (normal temperature, normal pressure converted value) for several hours at 150 to 300 ° C. under normal pressure. Pre-processing. The contact body is brought into contact with alcohol vapor. The contact method is fixed floor method, moving floor method,
Any of a fluidized bed system and the like can be adopted. In some cases, the alcohol vapor can be brought into contact with the touch body in a batchwise manner. The contact time between the alcohol vapor and the contact body is 20,0 at the gas space velocity (GHSV) at normal temperature and normal pressure.
00 to 1,000 hours- ¹ is preferred. The reaction temperature is preferably 1
The reaction temperature is from 00 to 300 ° C, more preferably from 150 to 210 ° C, and the reaction may be carried out under normal pressure or under pressure. The reaction temperature and pressure can be appropriately selected from a range in which the system can be kept in a gas phase.

When the reaction is carried out in a liquid phase, metal silicon and an alcohol are reacted in a solvent in the presence of the above-mentioned copper alkoxide catalyst. As the solvent, decane, dodecane,
Paraffinic hydrocarbons such as pentadecane and alkylbenzene hydrocarbons such as diethylbenzene and dodecylbenzene can be preferably used. Reaction temperature 100-2
At 50 ° C., the alcohol was added at a concentration of 0.
It is preferable to supply and react at 1 to 5 mol / hour.

The following examples illustrate the invention in more detail.

[0015]

【Example】

Example 1 Metal silicon (manufactured by Towa Kako Co., Ltd., purity 98.5%
0.10 g of copper (II) methoxide (manufactured by Aldrich) was added to 1.0 g of a product which had been sieved to 63 to 106 μm and then washed with ion-exchanged water, and mixed thoroughly to obtain a touch body.

After 1.0 g of the contact body was charged into a fixed bed reactor made of Pyrex glass having an inner diameter of 10 mm, the reactor was cooled to 2 g.
The contact body was pretreated by heating to 00 ° C. and flowing helium gas at 1.0 liter / hour (normal temperature, normal pressure converted value) for 1 hour.

Next, the methanol partial pressure was set to 56 kPa, methanol was supplied to the reactor at a supply rate of 38 mmol / hour by a micro feeder, and trimethoxysilane was produced in a gas phase. The reaction conditions were a reaction temperature of about 200 ° C. and a reaction pressure of 1 atm. The reaction products were analyzed every 5 minutes by gas chromatography connected to the outlet of the reaction tube. As a result, trimethoxysilane started to form without an induction period, and the conversion of silicon metal after 4 hours from the start of the reaction was 21%, and the selectivity for trimethoxysilane was 91%. The main product other than trimethoxysilane was tetramethoxysilane. The contact time of the contact body with methanol vapor is determined by the gas space velocity (GHSV).
(Normal temperature, normal pressure converted value) 2,300 hours- ¹ . Example 2 Under a nitrogen atmosphere, 0.10 g of copper (II) methoxide was dissolved in 30 ml of dimethyl ketone. After adding 1.0 g of metallic silicon to the obtained solution, it was immediately evaporated to dryness at 40 to 50 ° C. under reduced pressure using a rotary evaporator to obtain a touch body. This touch body was pretreated in the same manner as in Example 1,
Then, it was made to react with methanol in the same manner as in Example 1.
As a result, the conversion of metallic silicon 4 hours after the start of the reaction was 2
8%, and the selectivity for trimethoxysilane was 92%. Example 3 A contact body was prepared and pretreated in the same manner as in Example 1 except that 0.12 g of copper (II) ethoxide (manufactured by Aldrich) was used instead of copper (II) methoxide. Reaction was carried out with methanol under the same conditions as in 1. Table 1 shows the results
Shown in Example 4 Copper (II) ethoxide instead of copper (II) methoxide.
A touch body was manufactured and pretreated in the same manner as in Example 2 except that 12 g was used, and then reacted with methanol under the same conditions as in Example 2. Table 1 shows the results. Comparative Example 1 A contact body was produced in the same manner as in Example 1 except that 0.079 g of copper (I) chloride (Kanto Chemical Co., Ltd., special grade) was used instead of copper (II) methoxide, and pretreatment was performed. The reaction was then performed under the same conditions as in Example 1. Table 1 shows the results. Comparative Example 2 Copper (I) chloride 0.079 instead of copper (II) methoxide
A touch body was manufactured in the same manner as in Example 2 except that g was used.
A pretreatment was performed, and then the reaction was carried out with methanol under the same conditions as in Example 2. Table 1 shows the results. Example 5 A reaction for producing triethoxysilane was carried out in the same manner as in Example 4 except that ethanol was used instead of methanol. Table 1 shows the results.

[0018]

[Table 1]

* Conversion and selectivity after 4 hours of reaction

[0020]

According to the method of the present invention, since the copper catalyst does not contain chlorine, no chlorine compound is produced as a by-product, no chlorine is mixed in the product, and a corrosion-resistant reactor is used. No need. Moreover, according to the present invention, trialkoxysilane can be produced at a high conversion and selectivity. Therefore, the method of the present invention has high industrial utility.

Claims (1)

(57) [Claims] 1. A method for producing trialkoxysilane by reacting metal silicon and alcohol in the presence of a catalyst, wherein a copper alkoxide is used as the catalyst.