JPH0665257A - Production of trialkoxysilane - Google Patents

Abstract

PURPOSE:To obtain a method for producing a trialkoxysilane using a catalyst having high activity and selectivity and producing a relatively small amount of chlorine compounds. CONSTITUTION:The objective method for producing a trialkoxysilane comprise reacting metallic silicon with an alcohol in the presence of (a) a copper alkoxide and a metallic halide or (b) an alkoxycopper halide used as a catalyst.

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 with alcohol in the presence of a catalyst.

[0002]

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 produced. It is a compound useful as a raw material.

Conventionally, as a method for producing an 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 Method for producing dialkoxysilane (JP-B-37-17967), (3) Method for producing methoxysilane using a reaction solvent mainly containing dodecylbenzene (JP-A-55-76891), (4) Cu ( A method for producing an alkoxysilane by reacting silicon and alcohol in a liquid phase using OH) ₂ as a catalyst and an aromatic solvent (Japanese Patent Laid-Open No. Sho 63-63)
-258481) and many other methods were known.

Recently, it has been found that when copper chloride is used as a catalyst in a method of 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 an excellent one.

[0005]

However, this method has a drawback that chlorine compounds generated due to chlorine in the catalyst are mixed in the product. In particular, when trialkoxysilane is used as a raw material for producing a silane coupling agent, dechlorination treatment is required. Furthermore, 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.
For example, the Cu (OH) ₂ catalyst of the above (4) has a drawback of being unstable.

[0007] Therefore, an object of the present invention is to provide a method for producing trialkoxysilane using a catalyst having high activity and selectivity and a relatively small amount of chlorine compounds generated.

[0008]

The present inventors have previously found that when a copper alkoxide is used as a catalyst instead of a conventional copper chloride catalyst, a high activity equivalent to or higher than that of copper chloride can be obtained, and It was found that no generation of chlorine compounds was observed (Japanese Patent Application No. 354055). However, with this catalyst, the selectivity of trialkoxysilane was slightly inferior.
Therefore, when the present inventors further used a copper alkoxide together with a metal halide, it was possible to further improve the selectivity of trialkoxysilane as compared with the case where the copper alkoxide was used alone, and moreover, the activity of the catalyst was that copper alkoxide was used. The inventors have found that the level is as high as when used alone, and that halogen contamination in the product can be reduced as compared with the case of a conventional catalyst containing copper chloride alone, and arrived at the present invention.

That is, the present invention provides a method for producing trialkoxysilane by reacting metal silicon with alcohol in the presence of a catalyst, wherein the catalyst is (a) copper alkoxide and metal halide, or (b) alkoxy. Provided is a method for producing a trialkoxysilane, which is characterized by using a copper halide.

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, and more preferably 0.5 to 5 mol / hour with respect to 1 mol of metal silicon.

In the present invention, (a) a copper alkoxide and a metal halide, or (b) an alkoxy copper halide is used as a catalyst when the metal silicon is reacted with the above alcohol. The copper alkoxide is preferably a copper alkoxide represented by the following formula: Cu (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, an ethyl group, a propyl group, a butyl group, an isobutyl group,
Examples thereof include sec-butyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, heptyl group, octyl group, nonyl group and decyl group.

The metal halide is, for example, MX _n (where M is a metal element selected from the 4th to the 16th periods of the periodic table, and X is selected from F, Cl, Br and I). And halogens are n = 1 to 5, provided that when n is 2 or more, X may be the same or different. Specific examples of preferable metal halides include, for example, TiCl ₄ , VCl ₃ , CrCl ₃ , MnBr ₂ and F.
eCl ₂ , FeCl ₃ , CoBr ₂ , CoCl ₂ , Co
I ₂ , NiCl ₂ , CuCl, CuCl ₂ , ZnB
r ₂ , GaCl ₃ , GeI ₄ , ZrCl ₄ , NbC
l ₅ , MoCl ₅ , MoBr ₃ , PdCl ₂ , CdCl
₂ , InCl ₃ , InF ₃ , SnCl ₂ , SnCl ₄ ,
SnI ₂ , SnF ₂ , SbCl ₃ , SbCl ₅ , TeC
l ₄ , BiCl ₃ , BiBr ₃ , OsCl ₃ , Pb
F ₂ , PbCl ₂ , PbI _{2 and the} like can be mentioned. The metal halide may be a hydrate or an anhydride, but is preferably an anhydride.

Alkoxy copper halides are, for example, CuX
(OR) (where X and R are as defined above)
Indicated by. Such an alkoxy copper halide can be produced by the method described in, for example, Journal of Inorganic and Nuclea Chemistry (J. Inorg. Nucl. Chem.), Vol. 27, p. 59 (1965). The alkoxy copper halides can be used alone, but can also be used with the above-mentioned copper alkoxides or with the above-mentioned metal halides.

The ratio (molar ratio) of metal halide to copper alkoxide in the catalyst is preferably 0.001-10, more preferably 0.01-1 in the case of the above (a). In the case of (b) above, the ratio is necessarily 1 when the alkoxy copper halide is used alone. When using an alkoxy copper halide with a copper alkoxide,
1 mole of copper alkoxide for 1 mole of alkoxy copper halide
It is preferably used in an amount of up to 00 moles, and when an alkoxy copper halide is used with a metal halide, 20 moles of metal halide per mole of alkoxy copper halide.
It is preferably used in amounts up to molar.

The catalyst is used as a metal in an amount of preferably 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 touch body is prepared. As the method, for example, the powder of the catalyst is physically mixed, or the catalyst is dissolved in a ketone solvent such as dimethyl ketone, and the powder of metal silicon is added to the solution, which is then evaporated to dryness under reduced pressure. There is a method of doing so. The thus obtained tactile body is usually at normal pressure and
Under the condition of ~ 300 ° C, several liters / hour (normal temperature, atmospheric pressure conversion value) of several tens of minutes of an inert gas such as helium, hydrogen or a mixed gas of alcohol used in the reaction and an inert gas such as helium is used. It is pretreated by being distributed for a period of time to several hours. The contact body is contacted with alcohol vapor. As the contact method, any of a fixed bed method, a moving bed method, a fluidized bed method, etc. can be adopted. In some cases, the alcohol vapor and the contact body can be brought into contact with each other in a batch manner. The contact time between alcohol vapor and contact body is 20,000 to 1,000 hours- ¹ at room temperature and atmospheric pressure in gas space velocity (GHSV).
Is preferred. The reaction temperature is preferably 100 to 300 ° C,
The temperature is more preferably 150 to 220 ° 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 catalyst. As the solvent, paraffin hydrocarbons such as decane, dodecane and pentadecane, and alkylbenzene hydrocarbons such as diethylbenzene and dodecylbenzene can be preferably used. It is preferable that alcohol is supplied at a reaction temperature of 100 to 250 ° C. at a rate of 0.1 to 5 mol / hour per 1 mol of metal silicon for the reaction.

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

[0019]

【Example】

Example 1 Metallic silicon (manufactured by Towa Kako Co., Ltd., purity 98.5%,
1.0 g of copper (II) methoxide (manufactured by Aldrich Co.) and 0.006 g of cupric chloride were added to 1.0 g of the product which was sieved to 63 to 106 μm and washed with ion-exchanged water, and mixed sufficiently. I got a touch.

1.0 g of this contact body was charged into a Pyrex glass fixed bed reactor having an inner diameter of 10 mm, and then the reactor was replaced with 1
After heating to 30 ° C., helium gas was passed for 10 minutes at 1.0 liter / hour (normal temperature, atmospheric pressure conversion value).

Next, the partial pressure of methanol was set to 56 kPa, methanol was fed to the reactor at a feed rate of 38 mmol / hour with a micro feeder, and the temperature of the reactor was raised to 200 ° C. in about 30 minutes. By doing so, the pretreatment of the contact body was performed. Then, trimethoxysilane was produced in the gas phase at the same temperature. The reaction condition is a reaction temperature of about 20.
The reaction pressure was 0 ° C and the reaction pressure was 1 atm. The reaction product is
It was analyzed every 5 minutes by gas chromatography connected to the outlet of the reaction tube. As a result, the conversion rate of metallic silicon was 87% and the selectivity of trimethoxysilane was 96% after 7 hours from the start of supplying methanol. The main product other than trimethoxysilane was tetramethoxysilane. The contact time with the methanol vapor of the contact body was 2,300 hours ^-1 in gas space velocity (GHSV) (normal temperature, normal pressure conversion value). Example 2 A contact body was produced and pretreated in the same manner as in Example 1 except that the amount of cupric chloride was 0.012 g, and then reacted with methanol under the same conditions as in Example 1. The results are shown in Table 1.
Shown in. Example 3 A contact body was produced and pretreated in the same manner as in Example 1 except that 0.0088 g of cuprous chloride was used instead of cupric chloride, and then methanol was treated under the same conditions as in Example 1. Reacted with. The results are shown in Table 1. Example 4 A contact body was prepared and pretreated in the same manner as in Example 3 except that the amount of cuprous chloride was 0.018 g, and then reacted with methanol under the same conditions as in Example 1. The results are shown in Table 1.
Shown in. Example 5 Instead of copper (II) methoxide and cupric chloride, Journal of in Organic and Nuclea Chemistry (J. Inorg. Nucl. Chem.), No. 27.
Vol., Page 59 (1965), except that 0.10 g of methoxycopper chloride CuCl (OCH ₃ ) produced according to the method described in Example 1 was used to produce a contact body and pretreatment was conducted. Then, it was reacted with methanol under the same conditions as in Example 1. The results are shown in Table 1. Example 6 The same as Example 1 except that 0.12 g of copper (II) ethoxide (manufactured by Kojundo Chemical Co., Ltd.) and 0.012 g of cupric chloride were used instead of copper (II) methoxide and cupric chloride. A contact body was produced, pretreated, and then reacted with methanol under the same conditions as in Example 1. 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 0.11 g of cupric chloride was used instead of copper (II) methoxide and cupric chloride, pretreatment was performed, and then performed. It was reacted with methanol under the same conditions as in Example 1. The results are also shown in Table 1. Comparative Example 2 A contact body was produced in the same manner as in Comparative Example 1 except that 0.08 g of cuprous chloride was used instead of cupric chloride, and then pretreated in the same manner as in Example 1, It was reacted with methanol under the same conditions as in Example 1. The results are also shown in Table 1. Comparative Example 3 A contact body was produced in the same manner as in Comparative Example 1 except that 0.10 g of copper (II) methoxide was used instead of cupric chloride, and then a pretreatment was performed in the same manner as in Example 1. The reaction was carried out with methanol under the same conditions as in Example 1 except that the reaction temperature was 175 ° C. The results are also shown in Table 1. Example 7 A contact body was produced and pretreated in the same manner as in Example 6.
Next, a reaction was performed under the same conditions as in Example 1 except that ethanol was used instead of methanol to produce triethoxysilane. The results are shown in Table 1.

[0022]

[Table 1]

* 1 Cl / Cl + OR (mol%), R = Me or Et
_{(Me = CH 3, Et =} C 2 H 5) * 2 response after 7 hours conversion and selectivity Example 8 metal silicon (Towa Kako Co., Ltd., 98.5% pure,
1.0 g of copper (II) methoxide (manufactured by Aldrich) and 1.0 g of anhydrous ferric chloride 14.3 m after sieving to 63 to 106 μm and washing with ion-exchanged water)
g was added and mixed well to obtain a contact body.

1.0 g of this contact body was filled in a Pyrex glass fixed bed reactor having an inner diameter of 10 mm, and then the reactor was set to 1
After heating to 30 ° C., helium gas was passed for 10 minutes at 1.0 liter / hour (normal temperature, atmospheric pressure conversion value). Further, the partial pressure of methanol was set to 56 kPa, methanol was supplied to the reactor at a feed rate of 38 mmol / hour with a micro feeder, and the temperature of the reactor was raised from 130 ° C. to 200 ° C. over about 30 minutes. The pretreatment of the touch body was performed.

Next, production of trimethoxysilane in the gas phase
I went. The reaction conditions are a reaction temperature of 200 ° C. and a reaction pressure of 1
It was atm. The reaction product is connected to the outlet of the reaction tube.
Gas chromatography was performed and analyzed every 5 minutes. So
As a result of the
The conversion rate is 84%, and the selectivity of trimethoxysilane is
It was 96%. In addition, other than trimethoxysilane
The by-product was tetramethoxysilane. Tactile meta
The contact time with the nole vapor is the gas space velocity (G.H.S.V.).
(Room temperature, atmospheric pressure conversion value) 2,300 hours^-1Met.Example 9 Instead of anhydrous ferric chloride, anhydrous cobalt chloride (CoCl
₂) In the same manner as in Example 8 except that 11.5 mg was used.
The tactile body is manufactured, pretreated and then as in Example 8.
It was made to react with methanol under the conditions. The results are shown in Table 2.Example 10 Instead of anhydrous ferric chloride, anhydrous cobalt bromide (CoBr
₂) In the same manner as in Example 8 except that 19.3 mg was used.
The tactile body is manufactured, pretreated and then as in Example 8.
It was made to react with methanol under the conditions. The results are shown in Table 2.Example 11 Instead of anhydrous ferric chloride, anhydrous molybdenum pentachloride (Mo
Cl_Five) Same as Example 8 except using 24.2 mg
To produce a contact body, pretreatment is performed, and then the same as in Example 8 is performed.
It was made to react with methanol under the same conditions. The results are shown in Table 2.
YouExample 12  Instead of anhydrous ferric chloride, anhydrous stannous chloride (SnCl 2
₂) In the same manner as in Example 8 except that 16.8 mg was used.
The tactile body is manufactured, pretreated and then as in Example 8.
It was made to react with methanol under the conditions. The results are shown in Table 2.Example 13 Instead of anhydrous ferric chloride, anhydrous bismuth trichloride (BiC
l₃) In the same manner as in Example 8 except that 27.9 mg was used.
To produce a contact body, pretreatment, and then the same as in Example 8
It was made to react with methanol on condition of. The results are shown in Table 2.Example 14 Instead of copper (II) methoxide, copper (II) ethoxide (high
Purity Chemical Co., Ltd.) Same as Example 8 except that 0.12 g was used.
A contact body is manufactured in this manner, pretreated, and then used in Example 8.
It was made to react with methanol under the same conditions as. The results are shown in Table 2.
Show.

[0026]

[Table 2]

* 1 MX _n / (MX _n + Cu (OR) ₂ ) (mol%), R = Me or Et (Me = CH ₃ , Et = C ₂ H ₅ ) * 2 Conversion after 7 hours of reaction And selectivity

[0028]

According to the present invention, trialkoxysilane can be produced at a much higher conversion rate than when copper chloride is used alone, and when copper chloride is used alone. Can be performed with the same high selectivity. Moreover, in the present invention, since the chlorine content in the catalyst is relatively low, the chlorine content in the product is small and it is not necessary to use a corrosion resistant reactor. Therefore, the method of the present invention is industrially highly useful.

Claims (2)

[Claims] 1. A method for producing trialkoxysilane by reacting metal silicon and alcohol in the presence of a catalyst, wherein (a) a copper alkoxide and a metal halide, or (b) an alkoxy copper halide is used as the catalyst. A method for producing a trialkoxysilane, which comprises using the same. 2. The method according to claim 1, wherein (b) alkoxy copper halide is further used in combination with copper alkoxide or metal halide as a catalyst.