JPH05170773A - Production of trialkoxysilane - Google Patents

Abstract

PURPOSE:To obtain a method for producing a trialkoxysilane using a catalyst having high activity without producing chlorine compounds. CONSTITUTION:The objective method for producing a trialkoxysilane by reacting metallic silicon with an alkyl alcohol in the presence of a copper alkoxide.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Trialkoxysilane has a highly reactive silicon-hydrogen bond and is easily added to various olefins or acetylenes. Therefore, compounds having various functions such as silane coupling agents can be used. It is a compound useful as a raw material for production.

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

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

[0005]

However, this method has a drawback that chlorine compounds generated due to chlorine in the catalyst are mixed in the product. Particularly, when trialkoxysilane is used as a raw material for producing a silane coupling agent, dechlorination treatment is required. Moreover, this chlorine compound can also cause corrosion of the equipment used in the reaction.

As a catalyst for this reaction, a compound that can substantially replace copper chloride has not been found yet.

Therefore, an object of the present invention is to provide a method for producing trialkoxysilane using a catalyst which has high activity and does not generate chlorine compounds.

[0008]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies as to a method for producing trialkoxysilane, and as a result, when copper alkoxide was used as a catalyst, a high activity equal to or higher than that of copper chloride was obtained. The present invention has been completed by finding that it is possible and that no chlorine compound is generated.

That is, the present invention provides a method for producing trialkoxysilane by reacting metallic silicon and 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 preferably supplied at 0.1 to 20 mol / hour, more preferably 0.5 to 5 mol / hour with respect to 1 mol of metal silicon.

In the present invention, copper alkoxide is used as a catalyst when reacting metallic silicon with the above alcohol. The copper alkoxide is preferably of the formula Cu
A copper alkoxide represented by (OR) ₂ (wherein R represents an alkyl group having 1 to 10 carbon atoms). The alkyl group of R may be linear or branched. Examples of such an alkyl group include a methyl group,
Ethyl group, propyl group, butyl group, isobutyl group, sec-
Butyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, heptyl group, octyl group, nonyl group,
A decyl group and the like can be mentioned. 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, based on 1 mol of metal silicon.

In the method of the present invention, the reaction can be carried out in the gas phase or the liquid phase. When it is performed in the gas phase, for example, it is performed as follows. First, a contact body is prepared. As the method, for example, powder of metal silicon and copper alkoxide is physically mixed, or copper alkoxide is dissolved 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 contact body is usually passed under an atmospheric pressure of 150 to 300 ° C. under an inert gas such as helium gas or a hydrogen flow at several liters / hour (normal temperature, atmospheric pressure conversion value) for several hours. Pretreat by The contact body is contacted with alcohol vapor. The contact method is fixed bed method, moving bed method,
Any of the fluidized bed system and the like can be adopted. In some cases, the alcohol vapor and the contact body may be brought into contact with each other in a batch manner. The contact time between alcohol vapor and the contact body is 20,0 at the gas space velocity (GHSV) at room temperature and pressure.
00 to 1,000 hours- ¹ is preferred. The reaction temperature is preferably 1
The 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 the range in which the system can be kept in the gas phase.

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

The present invention will be described in more detail by the following examples.

[0015]

【Example】

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

1.0 g of this contact body was packed in a Pyrex glass fixed bed reactor having an inner diameter of 10 mm, and then the reactor was replaced with 2 reactors.
The contact body was pretreated by heating at 00 ° C. and flowing helium gas at 1.0 liter / hour (normal temperature, atmospheric pressure conversion value) for 1 hour.

Next, the partial pressure of methanol was set to 56 kPa, and methanol was fed to the reactor with a microfeeder at a feed rate of 38 mmol / hour to produce trimethoxysilane in the gas phase. The reaction conditions were a reaction temperature of about 200 ° C. and a reaction pressure of 1 atm. The reaction product was analyzed every 5 minutes by gas chromatography connected to the outlet of the reaction tube. As a result, trimethoxysilane started to be generated without an induction period, the conversion rate of metallic silicon was 21% 4 hours after the start of the reaction, and the selectivity of trimethoxysilane was 91%. The main product other than trimethoxysilane was tetramethoxysilane. The contact time with methanol vapor of the contact body is gas space velocity (GHSV)
(At room temperature and atmospheric pressure) It was 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 metal 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 contact body. This contact was pretreated as in Example 1,
Then, it was reacted with methanol in the same manner as in Example 1.
As a result, the conversion rate of metallic silicon 4 hours after the start of the reaction was 2
8%, and the selectivity of trimethoxysilane was 92%. Example 3 A contact body was produced in the same manner as in Example 1 except that 0.12 g of copper (II) ethoxide (manufactured by Aldrich) was used in place of copper (II) methoxide, pretreatment was carried out, and then Example was performed. It was reacted with methanol under the same conditions as in 1. The results are shown in Table 1.
Shown in. Example 4 Instead of copper (II) methoxide, copper (II) ethoxide 0.
A contact body was prepared 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. The results are shown in Table 1. 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 (manufactured by Kanto Chemical Co., Inc., special grade) was used instead of copper (II) methoxide, and pretreatment was performed. Then, the reaction was carried out with methanol under the same conditions as in Example 1. The results are shown in Table 1. Comparative Example 2 Copper (I) chloride 0.079 instead of copper (II) methoxide
A contact body was produced in the same manner as in Example 2 except that g was used.
Pretreatment was performed, and then the reaction was carried out with methanol under the same conditions as in Example 2. The results are shown in Table 1. 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. The results are shown in Table 1.

[0018]

[Table 1]

* Conversion rate and selectivity after 4 hours of reaction

[0020]

In the method of the present invention, since the copper catalyst does not contain chlorine, chlorine compounds are not produced as a by-product, chlorine is not mixed in the product, and a corrosion-resistant reactor is used. There is no need. Moreover, according to the present invention, trialkoxysilane can be produced with high conversion and selectivity. Therefore, the method of the present invention is industrially highly useful.

Claims (1)

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