JPH0344393A - Production of trimethoxysilane - Google Patents

Abstract

PURPOSE:To obtain the subject compound in high yield at a low cost by reacting methyl alcohol in the vapor phase in the presence of a catalyst prepared by supporting copper chloride on metallic silicon. CONSTITUTION:For example, metallic silicon is added to an aqueous solution of ammonia containing copper chloride dissolved therein, etc., and the solvent is then evaporated by heating, etc., to provide a supported catalyst, which is subsequently pretreated in a gas stream, such as hydrogen. Methanol vapor is then brought into contact with the aforementioned pretreated supported catalyst (the contact time is 20000-1000hr<-1> gas space velocity at ordinary temperature under ordinary pressure) and reacted at 180-300 deg.C under ordinary or higher pressure by a fixed bed method to afford the objective compound.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a method for producing trimethoxysilane, and more specifically, the present invention relates to a method for producing trimethoxysilane, and more particularly, the present invention relates to a method for producing trimethoxysilane, and more specifically, the production of methyl alcohol in a gas phase in the presence of a catalyst in which copper chloride is supported on metal silicon. The present invention relates to a method for producing trimethoxysilane by reaction.

Technical Background of the Invention Trimethoxysilane has a highly reactive silicon-hydrogen bond and is easily added to various olefins or acetylenes, so it is used as a raw material for producing compounds with various functions, such as silane coupling agents. It is a compound useful as Therefore, there is a strong desire to develop a method for producing C1 trimethoxysilane that is cheap and efficient.

Heretofore, the following methods have been disclosed as methods for producing alkoxysilanes including methoxysilane by reacting metal silicon and alkyl alcohols in the presence of a copper catalyst.

(a) Reacting methanol in the gas phase at 280°C in the presence of a catalyst obtained by heating a mixture of 90% metallic silicon and 10% copper at 050°C for 2 hours in a hydrogen stream. Method for producing tetramethoxysilane by (Journal
of American Chemical Society! -(J, o
l Am, Chem 5o (), vol. 70, 2170-2
p. 171, 1948).

(b) A method for producing trialkoxysilane and dialkoxysilane in a gas phase by blowing alkyl alcohol vapor into a fluidized bed formed of finely ground silicon and a catalyst (Japanese Patent Publication No. 17967/1983).

(c) A method for producing trimethoxysilane and tetramethoxysilane by suspending the contact body used in method (a) in silicone oil and reacting it in a liquid phase at 280°C (Inorganic Chemistry (Inorg, C.
Hell, ), Vol. 9, No. 5, pp. 1071-1075, 1970).

(d) Reduce the water content of methyl alcohol in the reaction system to 200
Method for producing methoxysilane by maintaining the concentration below 0 ppm and reacting in a solvent (Japanese Unexamined Patent Publication No. 55-28928)
.

(e) A method for producing methoxysilane using a reaction solvent mainly composed of dodecylbenzene (Japanese Patent Application Laid-open No. 76891/1983).

(F) A method for producing an alkoxysilane using dialkylbenzene having a boiling point in the range of 300 to 480°C as a reaction solvent (Japanese Patent Application Laid-open No. 108094/1983).

(g) Method for producing alkoxysilane using a reaction solvent mainly containing hydrogenated triphenyl (Japanese Patent Application Laid-Open No. 57-9959
Publication No. 3).

(h) React alkyl alcohol in a reaction medium with a catalyst in which silicon metal and a copper catalyst have been previously heat-treated in a hydrogen gas atmosphere, or with the catalyst in the presence of an alkali metal alcoholade or an alkali metal as a co-catalyst. Examples include a method for producing alkoxysilane (Japanese Unexamined Patent Publication No. 62-96433).

However, the manufacturing method disclosed above has the following problems. That is, in a method in which methanol is reacted in the gas phase in the presence of a catalyst obtained by heating a mixture of metallic silicon and copper in a hydrogen stream, tetramethoxysilane is produced as the main component6. There was a problem that the desired trimethoxysilane could not be obtained.

In addition, in the production method of methoxysilane by blowing methanol vapor into a fluidized bed formed with silicon and a catalyst, the selectivity of trimethoxysilane is about 45% when a hydrogen stream is not accompanied by methanol. Moreover, when a hydrogen stream is accompanied by methanol, the selectivity of trimethoxysilane is about 78%, and in any case, there is a problem that the selectivity of trimethoxysilane is low.

In addition, methods (c) to (h) are all liquid phase reactions, and although trimethoxysilane is obtained as the main component, the silicon conversion rate is low, the reaction rate is slow, or the selectivity of trimethoxysilane is low. There was a problem that it was not satisfactory as an industrial manufacturing method due to the low .

Furthermore, in the liquid phase reaction, factors other than the original chemical reaction are involved, such as the activity of the catalyst changing depending on the type or amount of reaction medium used, perhaps because the contact efficiency between metal silicon and the copper catalyst changes. There were problems with the impact on the

Purpose of the Invention The present invention provides low silicon conversion, slow reaction rate, and low selectivity of trimethoxysilane when producing trimethoxysilane from metallic silicon and methyl alcohol in the presence of a copper catalyst. The purpose of this invention is to solve the problems associated with the prior art, and to provide an inexpensive and efficient method for producing trimethoxysilane.

Summary of the Invention The present inventors believe that it would be more advantageous if trimethoxysilane could be produced by a gas phase reaction than by a liquid phase reaction in which the catalytic activity changes depending on the type of reaction medium or the amount of reaction medium. , various methods for producing trimethoxysilane in the gas phase were investigated.

As a result, they discovered that trimethoxysilane could be produced with high activity and high selectivity in the gas phase by using a catalyst in which chlorinated steel was supported on metal silicon, and the present invention was completed.

That is, in the method for producing trimethoxysilane according to the present invention, when producing methoxysilane by reacting metallic silicon and methyl alcohol in the presence of a copper catalyst, in the presence of a catalyst in which copper chloride is supported on metallic silicon. It is characterized by the fact that the reaction is carried out in the gas phase.

According to the present invention, trimethoxysilane can be obtained with high selectivity and high yield.

DETAILED DESCRIPTION OF THE INVENTION The method for producing trimethoxysilane according to the present invention will be specifically described below.

The catalyst used in the present invention is, for example, an ammonia aqueous solution in which copper (I) chloride is dissolved, a dimethyl sulfide solution in which copper (I) chloride is dissolved, or a chloride! (U)
It can be easily prepared by adding metal silicon to a methanol solution in which is dissolved and evaporating the solvent by heating or under reduced pressure. In this specification, the catalyst prepared as described above is referred to as a supported catalyst.

In the present invention, the supported catalyst thus prepared is further pretreated under a helium or hydrogen gas flow. This can be done by filling the contact body with a flow of inert gas such as helium or hydrogen for several hours at normal pressure and 250 to 500°C at a rate of several 1/h (normal pressure/normal temperature equivalent). can.

In the supported catalyst prepared in this way, copper chloride (I) is supported on metal silicon, so copper chloride (I) 1)
This improves the contact efficiency between metal silicon and the reaction represented by the following formula (1), which makes it easier for the reaction represented by the following formula (2) to occur. It is thought that the catalytic activity is improved by the formation of the catalytic agent.

In addition, in the pretreatment of the supported catalyst prepared in the present invention, especially when copper chloride (n) supported on silicon is pretreated with hydrogen, the copper chloride (n) is reduced and the copper chloride ( 1) and is pretreated with an inert gas such as helium, it is estimated that the reaction represented by the following equation (1) is promoted.

4CuCjl +S i→4Cu+S icu (
1) 3Cu +S i →Cu3S i
(2) In the present invention, the supporting ratio of copper chloride to metal silicon is 0.1 to 20% by weight, preferably 0.1 to 20% by weight. 5～
It is about 15% by weight.

Contact Conditions The contact between the methyl alcohol vapor according to the present invention and the pretreated supported catalyst can be appropriately selected from conventionally known methods. For example, a method of bringing methanol vapor and the supported catalyst into contact in a fixed bed method, a moving bed method, a fluidized bed method, etc. can be employed. Further, depending on the case, the methanol vapor and the supported catalyst may be brought into contact in a batch manner.

The contact time between methanol vapor and the supporting catalyst is 20.00 at gas hourly space velocity (G, I (, S, V) at normal pressure and room temperature.
It is preferably about 0 to 1.000 hours-1.

In the present invention, the reaction temperature between metal silicon and methyl alcohol is preferably about 180 to 300°C, preferably about 200 to 280°C, and the reaction pressure may be normal pressure or increased pressure. The reaction temperature and reaction pressure can be appropriately selected from a range that allows the system to be maintained in the gas phase.

Effects of the Invention According to the method of the present invention, trimethoxysilane can be efficiently produced with high activity. In addition, the isotropy of the present invention allows trimethoxysilane to be obtained with a higher selectivity than the liquid-phase technology, and thus has the effect of reducing operating costs.

EXAMPLES The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples.

Furthermore, the percentages in the examples are based on weight unless otherwise specified.

Example 1 Under a nitrogen atmosphere, copper chloride (■) (Kanto Kagaku (for use type, special grade) was dissolved in ammonia water (Kanto Kagaku (for use type, special grade)), and metal silicon (added) was added to the resulting solution. Immediately after adding 100 to 110 µm (manufactured by Rikagaku ■, purity 99.5%, sieved to 63-45μ and washed with ion-exchanged water)
The mixture was evaporated to dryness at .degree. C. to obtain a supported catalyst in which 2.5% of copper(I) chloride was supported on metal silicon.

After filling 0.5 g of the catalyst thus obtained into a Pyrex glass fixed bed reactor with an inner diameter of 10 mm, the reactor was heated to 450°C and helium gas was introduced at 1.81/h.
The supported catalyst was pretreated by flowing the mixture at room temperature and pressure for 1 hour.

Then, the reaction temperature was set to 260°C and the methanol partial pressure was set to 99Kp.
methanol was supplied to the reactor using a microfeeder at a supply rate of 106 mmol/hour to produce trimethoxysilane in the gas phase. The reaction product was collected using a gas chromatograph (S) connected to the outlet of the reaction tube.
E-30, 2m column, 100°C) and analyzed every 5 minutes.

As a result, methoxysilane begins to grow without an induction period,
Two hours after the start of the reaction, the production rate of methoxysilane reached 8 mmol/hour, and then gradually decreased. Reaction start 5
The conversion rate of metallic silicon after hours was 84%, and the selectivity of trimethoxysilane was 94%. Note that the methoxysilane product other than trimethoxysilane was tetramethoxysilane.

Example 2~]-0 Example 1 except that the supporting ratio of copper chloride (1) in the supported catalyst, pretreatment conditions, and reaction conditions were changed as shown in Table 1.
The supported catalyst was prepared, pretreated, and trimethoxysilane was produced in the same manner as described above.

Table 1 shows the induction period until the start of the reaction, the production rate of methoxysilane, the conversion rate of metallic silicon 5 hours after the start of the reaction, and the selectivity of trimethoxysilane.

Example 11 After dissolving copper (I) chloride in dimethyl sulfide (manufactured by Kanto Kagaku ■, special grade product) and adding metallic silicon to the resulting solution,
Immediately evaporate to dryness at about 50°C to obtain 10% copper(I) chloride.
A supported catalyst was obtained in which the metal silicon was supported.

After filling 0.5 g of the catalyst thus obtained into a Pyrex glass fixed bed reactor with an inner diameter of 10 mm, the reactor was heated to 260°C and helium gas was pumped in at 1.81/h.
The supported catalyst was pretreated by flowing the mixture at room temperature and pressure for 1 hour.

Next, the reactor was kept at 260°C, and the methanol partial pressure was 99K.
The production of trimethoxysilane in the gas phase was carried out by feeding methanol into the reactor at a feed rate of 106 mmol/h at 100 mA.

As a result, after an induction period of 10 to 15 minutes, methoxysilane began to be produced, and 2 hours after the start of the reaction, the production rate of methoxysilane reached 5 mmol/hour, and thereafter gradually decreased. The conversion rate of metallic silicon was 57% 5 hours after the start of the reaction.
The selectivity of trimethoxysilane was 94%.

1st Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 (%) ■ 2.5 2.5 2.5 0 2.5 2.5 ( /'C/hr) Helium/45Q/1 Helium/45G/1 Helium/450/1 Helium/45G/1 Helium/350/1 Helium/26G/1 Helium/260/1 Helium/260/1 Hydrogen/260 /1 (℃/Kpa) 260/99 260/99 240/99 220/99 260/99 260/99 260/99 260/99 260/99 Methoxysilane (mmol/hour) Decrease after 4 2.3 Decrease after approx. 1 Approximately 1 ■ 4 (after 1 hour) Decreased thereafter 5 (after 4 hours) Example 12-t3 Same as Example 1■ except that the loading rate of copper (I) chloride was changed as shown in Table 2. The supported method was prepared, pretreated, and trimethoxysilane was produced. Table 2 shows the induction period until the start of the reaction, the production rate of methoxysilane, the conversion rate of silicon metal 5 hours after the start of the reaction, and the selectivity of trimethoxysilane.

Example 14 Anhydrous copper chloride (■) (manufactured by Wako Tsumugi Pharmaceutical Co., Ltd., purity 95%) was dissolved in methanol, metal silicon was added to the resulting solution, and the methanol was immediately evaporated at room temperature using a rotary evaporator. Copper(II) chloride 2. A supported catalyst in which 5% was supported on metal silicon was obtained.

After filling 0.5 g of the catalyst thus obtained into a Pyrex glass fixed bed reactor with an inner diameter of 10 mm, the reactor was heated to 260°C and hydrogen gas was injected at 1.81/h (
The supported catalyst was pretreated by flowing the mixture at room temperature and pressure for 1 hour.

The reactor was then maintained at 260°C, and the methanol partial pressure was 99°C.
The production of trimethoxysilane in the gas phase was carried out by feeding methanol into the reactor at a feed rate of 106 mmol/h at K p a .

As a result, after an induction period of 30 minutes, methoxysilane began to grow, and 3.5 hours after the start of the reaction, the production rate of methoxysilane reached 12 mmol/hour, and then decreased. The conversion rate of metallic silicon 5 hours after the start of the reaction was 100%, and the selectivity of trimethoxysilane was 89%.

Examples 15 to 21 A supported catalyst was prepared and pretreated in the same manner as in Example 14, except that the loading ratio of copper chloride (n) on the supported catalyst and the pretreatment conditions were changed as shown in Table 3. Treatment and production of trimethoxysilane were carried out. Table 3 shows the induction period until the start of the reaction, the production rate of methoxysilane, the conversion rate of silicon metal 5 hours after the start of the reaction, and the selectivity of trimethoxysilane.

Comparative Example 1 A contact body was obtained by physically mixing 2.5% copper(I) chloride and 97.5% silicon metal. The touch body thus obtained is 0.
Pretreatment of the catalyst and production of trimethoxysilane were carried out in the same manner as in Example 1, except that 5 g was used and helium gas was passed at 260° C. for 1 hour.

As a result, after an induction period of 1 hour, methoxysilane started to be produced, and the production rate was about 0.5 mmol/hour. In addition, the conversion rate of metallic silicon 3 hours after the start of the reaction was 5
%, the selectivity of trimethoxysilane is 95%,
It was.

Claims (1)

[Claims] (1) When producing methoxysilane by reacting metallic silicon and methyl alcohol in the presence of a copper catalyst, the reaction is carried out in the gas phase in the presence of a catalyst in which copper chloride is supported on metallic silicon. A method for producing trimethoxysilane.