JP7012382B2 - Method for producing tetraalkoxysilane using a co-solvent - Google Patents

Description

The present invention relates to a highly efficient method for producing tetraalkoxysilane, and more particularly to a method for producing tetraalkoxysilane using an entrainer.

Tetraalkoxysilane is used as a raw material for producing various silane compounds, organic silicone polymers, various silylating agents, colloidal silica, ceramics and the like.
As a conventionally known industrial production method for alkoxysilanes, for example, natural silicon dioxide is used as a starting material, mixed with carbon and reduced at a high temperature to obtain metallic silicon, which is used as chlorine. A method of reacting silicon tetrachloride obtained by reaction with an alcohol using silicon tetrachloride as a raw material is known (see Patent Document 1). Further, a production method in which metallic silicon and alcohol are directly reacted is also known (see Patent Document 2).
However, all of these methods need to go through a process of manufacturing metallic silicon, which requires a high temperature, and have a problem of poor energy efficiency.
On the other hand, as a method for directly producing alkoxysilane from silica, a method for producing alkoxysilane by reacting silica with an alkyl carbonate using an alkali metal element or an alkaline earth metal element as a catalyst is known (Patent Document 3). 4). Since these methods do not use the above-mentioned metallic silicon as a raw material, they are advantageous in terms of energy efficiency, but at least twice the amount of alkyl carbonate, which is a relatively expensive compound, is added to silica as a stoichiometry. There is an economic problem as an industrial production method of tetraalkoxysilane.
The present inventors have found that tetramethoxysilane can be produced from methanol and silicon oxide as raw materials, react methanol with silicon oxide in the presence of carbon dioxide, and remove by-produced water using a molecular sieve. We have developed a method for obtaining tetramethoxysilane in high yield (see Patent Document 5).

Japanese Unexamined Patent Publication No. 62-114991 U.S. Pat. No. 2,473,260 Japanese Unexamined Patent Publication No. 2001-114786 Japanese Patent No. 3026371 JP-A-2017-88498

An object of the present invention is to provide a method capable of producing tetraalkoxysilane in an energy-saving manner and in a high yield.

As a result of diligent studies to solve the above problems, the present inventors conducted a reaction to produce tetraalkoxysilane from alcohol and silicon oxide in the presence of an aliphatic hydrocarbon solvent, and further, vaporized components of the reaction mixture. The present invention was completed by finding that a tetraalkoxysilane can be produced in a high yield by contacting with a molecular sieve.

That is, the present invention is as follows.
<1> The inclusion includes a first step of reacting an alcohol and silicon oxide in the presence of an aliphatic hydrocarbon solvent, and a second step of bringing the vaporized component of the reaction mixture obtained in the first step into contact with the molecular sieve. A characteristic method for producing a tetraalkoxysilane.
<2> The method for producing a tetraalkoxysilane according to <1>, wherein the first step is performed in the presence of an alkali metal compound and / or an alkaline earth metal compound.
<3> The first step and the second step are caused by the presence of the molecular sieve at a position in the reactor performing the first step so as not to come into contact with the liquid component and / or the solid component of the reaction mixture. The method for producing a tetraalkoxysilane according to <1> or <2>, which proceeds in one container.
<4> The molecular sieve is present in a container that performs the second step, which is different from the reactor that performs the first step, and an outward flow path for moving the vaporizing component from the reactor to the container. The first step and the second step proceed by connecting the reactor and the container through a return flow path for moving the component in contact with the molecular sieve from the container to the reactor. The method for producing a tetraalkoxysilane according to <1> or <2>.

According to the present invention, tetraalkoxysilane can be produced in high yield.

It is an example of the conceptual diagram of the apparatus which can be used in the manufacturing method of the tetraalkoxysilane of this invention. It is an example of the conceptual diagram of the apparatus which can be used in the manufacturing method of the tetraalkoxysilane of this invention.

In explaining the present invention, specific examples will be given, but the present invention is not limited to the following contents as long as it does not deviate from the gist of the present invention, and can be appropriately modified and carried out.

<Manufacturing method of tetraalkoxysilane>
The method for producing tetraalkoxysilane (hereinafter, may be abbreviated as "the production method of the present invention"), which is one aspect of the present invention, is a tetraalkoxysilane using a reaction for producing tetraalkoxysilane from alcohol and silicon oxide. It is a manufacturing method of the above, and is characterized by including the following first step and second step.
First step: A step of reacting alcohol and silicon oxide in the presence of an aliphatic hydrocarbon solvent (hereinafter, may be abbreviated as "first step").
Second step: A step of bringing the vaporized component of the reaction mixture obtained in the first step into contact with the molecular sieve (hereinafter, may be abbreviated as "second step").
The present inventors carry out a reaction to produce tetraalkoxysilane from alcohol and silicon oxide in the presence of an aliphatic hydrocarbon solvent, and further contact the vaporized component of the reaction mixture with a molecular sieve to increase the amount of tetraalkoxysilane. They found that it could be produced in yield.
Molecular sieves will be used as a dehydrating agent to remove the water produced by the reaction of alcohol and silicon oxide, but the aliphatic hydrocarbon solvent acts as an azeotropic solvent to promote the vaporization of the by-produced water. It is considered that dehydration proceeds efficiently. Further, it is considered that the aliphatic hydrocarbon solvent has an effect of suppressing the reverse reaction in which the produced tetraalkoxysilane is decomposed, and the reaction between the alcohol and silicon oxide is carried out in the presence of the aliphatic hydrocarbon solvent. Tetraalkoxysilanes can be produced in very high yields.
It should be noted that including the "first step" and the "second step" is not only a mode in which the first step and the second step proceed independently, but also the first step and the second step are in one container or different. A mode in which each progresses simultaneously in the container is also included.
Hereinafter, the "first step", the "second step" and the like will be described in detail.

(First step)
The first step is a step of reacting alcohol and silicon oxide in the presence of an aliphatic hydrocarbon solvent, but the type of alcohol is not particularly limited and may be appropriately selected according to the tetraalkoxysilane intended for production. Can be done. For example, if methanol is used as the alcohol, tetramethoxysilane can be produced, and if ethanol is used, tetraethoxysilane can be produced.
The alcohol may be either an aliphatic alcohol or an aromatic alcohol, and the hydrocarbon group in the alcohol may have a branched structure, a cyclic structure, a carbon-carbon unsaturated bond, or the like.
The number of carbon atoms of alcohol is usually 1 or more, preferably 2 or more, preferably 15 or less, more preferably 10 or less, still more preferably 8 or less, and the number of carbon atoms in the case of an aromatic alcohol is usually 6 or less. That is all.
Specific alcohols include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-propanol, 2-methyl-2-propanol, benzyl alcohol, phenol and the like. Be done. Of these, methanol, ethanol, 1-propanol and 1-butanol are preferable, and ethanol is more preferable. In the conventional method using metallic silicon, the yield of tetraalkoxysilane tends to decrease as the number of carbon atoms of the alcohol increases. However, by using the production method of the present invention, the yield is high. Tetraalkoxysilane can be produced at a rate.
The amount of alcohol used is usually 1 time or more, preferably 5 times or more, more preferably 10 times or more, and usually 10,000 times or less, preferably 5000 times or less, more preferably, with respect to the amount of substance of silicon oxide. Is less than 3000 times.

The first step is a step of reacting alcohol and silicon oxide in the presence of an aliphatic hydrocarbon solvent. Silicon oxide is a compound containing a silicon atom (Si) and an oxygen atom (O) as main constituent elements. It means that it may be a composite oxide with silicon monoxide (SiO), silicon dioxide (SiO ₂ ), or another metal such as zeolite.
Specific examples of silicon oxide include natural minerals such as silica stone, silica sand, diatomaceous earth, and quartz, calcined ash of silicon-containing plants, volcanic ash, silicates, silica gel derived from silica sol, fumed silica, silica alumina, and zeolite. And so on.

The first step is a step of reacting alcohol and silicon oxide in the presence of an aliphatic hydrocarbon solvent, and the aliphatic hydrocarbon solvent means an aliphatic hydrocarbon that can be a solvent under a reaction temperature and a reaction pressure. However, aliphatic hydrocarbons are not limited to linear saturated aliphatic hydrocarbons, but have a branched structure, a cyclic structure, a carbon-carbon unsaturated bond (carbon-carbon double bond, carbon-carbon triple bond), and the like. May have. The aliphatic hydrocarbon solvent is not limited to only one type, and two or more types may be mixed and used.
The number of carbon atoms of the aliphatic hydrocarbon solvent is usually 5 to 10.
The boiling point of the aliphatic hydrocarbon solvent is usually 25 to 200 ° C., preferably 30 ° C. or higher, more preferably 35 ° C. or higher, preferably 180 ° C. or lower, and more preferably 150 ° C. or lower. Within the above range, tetraalkoxysilane can be produced in a higher yield.
As a specific aliphatic hydrocarbon solvent,
N-pentane, i-pentane, cyclopentane, 2,2-dimethylpropane with 5 carbon atoms;
N-hexane, i-hexane, cyclohexane, 2,2-dimethylbutane, methylcyclopentane with 6 carbon atoms;
N-heptane, i-heptane, cycloheptane with 7 carbon atoms;
Examples thereof include n-octane, i-octane, and cyclooctane having 8 carbon atoms.
The amount of the aliphatic hydrocarbon solvent used is usually 0.01 times or more, preferably 0.1 times or more, more preferably 0.3 times or more, and usually 100 times the mass of the alcohol used in the reaction. It is fold or less, preferably 10 times or less, and more preferably 1 fold or less.

The first step is preferably carried out in the presence of an alkali metal compound and / or an alkaline earth metal compound. In the presence of an alkali metal compound or an alkaline earth metal compound, the cleavage of the silicon-oxygen bond of silicon oxide is promoted, and tetraalkoxysilane can be produced in a higher yield.
Examples of the alkali metal and alkaline earth metal in the alkali metal compound and the alkaline earth metal compound include lithium (Li), sodium (Na), magnesium (Mg), potassium (K), calcium (Ca), cesium (Cs) and the like. Can be mentioned. Examples of the counter ion include hydroxides, halides, oxides, carbonates, hydrogen carbonates, alkoxides, silicates, aluminates, phosphates, organic acid salts, sulfates, nitrates and the like. .. Of these, hydroxides, halides, carbonates and bicarbonates are preferred, with alkali metal hydroxides, alkali metal halides, alkali metal carbonates and alkali metal bicarbonates being more preferred.
Specific alkali metal compounds and alkaline earth metal compounds include lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, cesium hydroxide, lithium carbonate, sodium carbonate, potassium carbonate, cesium carbonate, and sodium fluoride. , Potassium fluoride, cesium hydroxide and the like. The alkali metal compound and the alkaline earth metal compound may be used not only in one type but also in combination of two or more types.
The total amount of the alkali metal compound and the alkaline earth metal compound used is usually 0 mol or more, preferably 0.001 mol or more, and usually 20 mol or less, preferably 10 mol or less, relative to 1 mol of silicon oxide (in the case of silicon dioxide). be. Within the above range, tetraalkoxysilane can be produced in a higher yield.

The reaction conditions of the first step are not particularly limited and can be appropriately selected depending on the intended purpose.
The reaction temperature in the first step is usually 150 ° C. or higher, preferably 180 ° C. or higher, more preferably 200 ° C. or higher, still more preferably 220 ° C. or higher, particularly preferably 240 ° C. or higher, and usually 400 ° C. or lower, preferably 350 ° C. or higher. ° C. or lower, more preferably 300 ° C. or lower, still more preferably 280 ° C. or lower, and particularly preferably 260 ° C. or lower.
The reaction pressure in the first step is usually 0.1 MPa or more, preferably 1.0 MPa or more, more preferably 3.0 MPa or more, and usually 60 MPa or less, preferably 30 MPa or less, more preferably 20 MPa or less.
The reaction time of the first step is usually 1 hour or more, preferably 5 hours or more, more preferably 10 hours or more, usually 168 hours or less, preferably 120 hours or less, and more preferably 100 hours or less.
Within the above range, tetraalkoxysilane can be produced in a higher yield.

(Second step)
The second step is a step of bringing the vaporized component of the reaction mixture obtained in the first step into contact with the molecular sheave, which functions as a molecular sieve and can adsorb water in the pores to dehydrate. There is no particular limitation as long as it is a certain material, and 3A, 4A, 5A, 13X and the like, which are A-type and X-type porous zeolites, can be preferably used, but 3A is particularly preferable. When it is 3A, water can be selectively removed and tetraalkoxysilane can be produced in a higher yield. The molecular sieve is used in an amount that can sufficiently remove water produced by the reaction between alcohol and silicon oxide.

The second step is a step of bringing the vaporized component of the reaction mixture obtained in the first step into contact with the molecular sieve, and the temperature of the molecular sieve is usually 30 ° C. or higher, preferably 40 ° C. or higher, and usually 80 ° C. Hereinafter, it is preferably 60 ° C. or lower. Within the above range, tetraalkoxysilane can be produced in a higher yield.
When the temperature of the container or the like in which the molecular sheave is installed is used for judgment instead of the temperature of the molecular sheave, the temperature is usually 25 ° C. or higher, preferably 30 ° C. or higher, more preferably 40 ° C. or higher. It is usually 100 ° C. or lower, preferably 80 ° C. or lower, and more preferably 60 ° C. or lower.
The method of controlling the temperature of the molecular sheave is to heat it using a heater, etc., to use the heat of the first step, to circulate constant temperature water or constant temperature oil on the outer surface of the container where the molecular sieve is installed, etc. Can be mentioned.

The apparatus used in the production method of the present invention is not particularly limited as long as it can perform the above-mentioned first step and second step, but the second step is different from the reactor in which the molecular sieve performs the first step. (See FIG. 1A) and an apparatus in which the molecular sieve is located in the reactor in which the first step is performed (see FIG. 1B). Hereinafter, each device will be described in detail with reference to the conceptual diagrams of the devices of FIGS. 1A and 1B.
The apparatus 101a of FIG. 1A has a configuration including a reactor 106 for performing the first step and a container 107 for performing the second step, and the container 107 for performing the second step is larger than the reactor 106 for performing the first step. It is installed above (high position). Alcohol 102, silicon oxide 103, an aliphatic hydrocarbon solvent, an alkali metal compound and the like are charged into the reactor 106 in which the first step is performed and heated to the reaction temperature to perform the first step. The vaporized component 104 of the reaction mixture obtained in the first step is charged into the container 107 for performing the second step in which the molecular sheave 105 is installed via the outward flow path 108, and the component in contact with the molecular sheave 105 is released. It will return to the reactor 106 that performs the first step via the return flow path 109. That is, the vaporization component 104 of the reaction mixture is brought into contact with the molecular sieve 105 in the container 107 for which the second step is performed, and the second step is performed.
The method for moving the vaporization component 104 of the reaction mixture to the container 107 for performing the second step is not particularly limited, but for example, the temperature of the connection portion 110 between the container for performing the second step and the outward flow path is set to 100 to 400 ° C. The range can be mentioned. The temperature of the connection portion between the container to which the second step is performed and the outward flow path is preferably 120 ° C. or higher, more preferably 150 ° C. or higher, preferably 350 ° C. or lower, and more preferably 300 ° C. or lower. Within the above range, the vaporization component of the reaction mixture can be vaporized from the reactor to the second step due to the temperature difference and / or the pressure difference in the reaction system without using a carrier gas, a compressor, or the like. Further, the components in contact with the molecular sieve can be transferred from the container in which the second step is performed to the reactor in which the first step is performed. The method of setting the temperature of the connection between the container and the outward flow path where the second step is performed to be in the range of 100 to 400 ° C. is to heat using a heater or the like, or to use the heat of the first step. Can be mentioned.
The temperature of the outward flow path is usually 100 ° C. or higher, preferably 120 ° C. or higher, more preferably 150 ° C. or higher, and usually 400 ° C. or lower, preferably 350 ° C. or lower, more preferably 300 ° C. or lower. From the viewpoint of improving the yield, it is preferable that the temperature of the outward flow path is higher than the reaction temperature.
The temperature of the return flow path is usually 25 ° C. or higher, preferably 40 ° C. or higher, more preferably 60 ° C. or higher, and usually 100 ° C. or lower, preferably 80 ° C. or lower.

The apparatus 101b of FIG. 1B is configured to include only the reactor 106 that performs the first step. Alcohol 102, silicon oxide 103, an aliphatic hydrocarbon solvent, an alkali metal compound, etc. are charged into the reactor 106 in which the first step is performed, and the molecular sieve 105 is further added to the liquid component and / or in the reactor 106 in which the first step is performed. The first step is performed by installing the compound in a position where it does not come into contact with the solid component (for example, above (high position)) and heating it to the reaction temperature. Then, the vaporization component 104 of the reaction mixture is brought into contact with the molecular sieve 105 in the reactor 106 for which the first step is performed, and the second step is performed. The device 101b is easy to maintain because it is easy to clean, and is advantageous in terms of cost. The apparatus 101b also includes an embodiment in which the reactors in which the first step and the second step are performed are linked by one linking group.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention can be appropriately modified as long as it does not deviate from the gist of the present invention. Therefore, the scope of the present invention should not be construed as limiting by the specific examples shown below.

<Example 1>
Silicon dioxide (Fuji Silysia Chemical CARiACT Q-10) 0.09 g, potassium hydroxide 0.0084 g, methanol 5.5 g, aliphatic in a 10 mL volume SUS autoclave (manufactured by Pressure Resistant Glass Industry Co., Ltd.) containing a magnetic stir bar. 2.5 g of n-pentane was added as a hydrocarbon solvent. Another 10 mL volume SUS autoclave (manufactured by Pressure Resistant Glass Industry Co., Ltd.) is equipped with 8.0 g of molecular sheave 3A (Merck Co., Ltd. molecular sheave 0.3 nm bead shape) at the top, and the two autoclaves are connected to each other. A vertically long reactor as shown in 1B was used. Next, argon gas was introduced from the cylinder at a temperature of 25 ° C., and the inside of the autoclave was replaced with argon gas and sealed. Then, the inside of the autoclave was heated to a reaction temperature of 260 ° C. while stirring at 1200 rpm, and the reaction was carried out for 6 hours. After cooling, the remaining gas was released and the reaction mixture was analyzed by gas chromatography (Shimadzu GC-2014 ATF / SPL). The yield of tetramethoxysilane based on silicon dioxide was 32%. The results are shown in Table 1.

<Example 2>
Tetramethoxysilane was produced by the same operation as in Example 1 except that the reaction conditions of Example 1 were 4.7 g of methanol and 3.3 g of n-pentane as an aliphatic hydrocarbon solvent. The yield of tetramethoxysilane based on silicon dioxide was 32%. The results are shown in Table 1.

<Example 3>
Tetramethoxysilane was produced by the same operation as in Example 1 except that the reaction conditions of Example 1 were 4.0 g of methanol and 4.0 g of n-pentane as an aliphatic hydrocarbon solvent. The yield of tetramethoxysilane based on silicon dioxide was 18%. The results are shown in Table 1.

<Example 4>
Tetramethoxysilane was produced by the same operation as in Example 1 except that the reaction conditions of Example 1 were 5.5 g of methanol and 2.5 g of cyclopentane as an aliphatic hydrocarbon solvent. The yield of tetramethoxysilane based on silicon dioxide was 27%. The results are shown in Table 1.

<Example 5>
Tetramethoxysilane was produced by the same operation as in Example 1 except that the reaction conditions of Example 1 were 6.0 g of methanol and 2.0 g of n-hexane as an aliphatic hydrocarbon solvent. The yield of tetramethoxysilane based on silicon dioxide was 22%. The results are shown in Table 1.

<Example 6>
Tetramethoxysilane was produced by the same operation as in Example 1 except that the reaction conditions of Example 1 were 5.5 g of methanol and 2.5 g of 2,2-dimethylbutane as an aliphatic hydrocarbon solvent. rice field. The yield of tetramethoxysilane based on silicon dioxide was 29%. The results are shown in Table 1.

<Example 7>
Tetramethoxysilane was produced by the same operation as in Example 1 except that 5.5 g of methanol and 2.5 g of sichexane as an aliphatic hydrocarbon solvent were used for the reaction conditions of Example 1. The yield of tetramethoxysilane based on silicon dioxide was 26%. The results are shown in Table 1.

<Example 8>
Silicon dioxide (Fuji Silysia Chemical CARiACT Q-10) 0.06 g, potassium hydroxide 0.0059 g, methanol 3.8 g, aliphatic in a 10 mL volume SUS autoclave (manufactured by Pressure Resistant Glass Industry Co., Ltd.) containing a magnetic stir bar. 1.8 g of n-hexane was added as a hydrocarbon solvent. In another 10 mL volume of SUS autoclave (manufactured by Pressure Resistant Glass Industry Co., Ltd.), 8.0 g of molecular sheave 3A (molecular sheave 0.3 nm bead-shaped manufactured by Merck Co., Ltd.) was installed at the top. A SUS316 tube with an inner diameter of 4.6 mm (108 in FIG. 1A) that can be heated using a ribbon heater as an outward flow path for the vaporization component of the reaction mixture to move so that these two autoclaves have the configuration shown in FIG. 1A. It was connected with a SUS316 tube (corresponding to 109 part in FIG. 1A) having an inner diameter of 4.6 mm as a return flow path for the component in contact with the molecular sieve to move. Next, argon gas was introduced from the cylinder at a temperature of 25 ° C., and the inside of the autoclave was replaced with argon gas and sealed. Then, the inside of the autoclave was heated to a reaction temperature of 200 ° C. while stirring at 1200 rpm, and the reaction was carried out for 6 hours. After cooling, the remaining gas was released and the reaction mixture was analyzed by gas chromatography (Shimadzu GC-2014 ATF / SPL). The yield of tetramethoxysilane based on silicon dioxide was 61%. The results are shown in Table 1.

<Example 9>
Tetramethoxysilane was produced by the same operation as in Example 8 except that the reaction conditions of Example 8 were 3.8 g of methanol and 1.8 g of n-heptane as an aliphatic hydrocarbon solvent. The yield of tetramethoxysilane based on silicon dioxide was 68%. The results are shown in Table 1.

<Example 10>
Tetraethoxysisilane was operated in the same manner as in Example 8 except that the reaction conditions of Example 8 were 3.8 g of ethanol, 1.8 g of n-pentane as an aliphatic hydrocarbon solvent, and the reaction temperature was 160 ° C. Was manufactured. The yield of tetraethoxysilane based on silicon dioxide was 49%. The results are shown in Table 1.

<Example 11>
Tetraethoxysisilane was produced by the same operation as in Example 10 except that the reaction conditions of Example 10 were 3.8 g of ethanol and 1.8 g of n-hexane as an aliphatic hydrocarbon solvent. The yield of tetraethoxysilane based on silicon dioxide was 56%. The results are shown in Table 1.

<Example 12>
A 200 mL volume autoclave (manufactured by Nitto High Pressure Co., Ltd.) equipped with a mechanical stirrer has an inner diameter of 4.6 mm that can be heated using a ribbon heater as an outward flow path for the vaporized components of the reaction mixture to move. A SUS316 tube (corresponding to 108 parts in FIG. 1) and a SUS316 tube having an inner diameter of 4.6 mm (corresponding to 109 parts in FIG. 1) were connected as a return flow path for moving components in contact with the molecular sieve. The temperature (T ₂ ) in the outbound flow path pipe was maintained at 249 ° C. during the reaction. Further, a SUS portable reactor (manufactured by pressure resistant glass) having an internal volume of 30 ml containing 25 g of molecular sieve 3A (manufactured by Merck: 2 mm beads) was connected to these tubes. Constant temperature water was circulated outside the portable reactor to maintain the temperature of the molecular sieve inside the portable reactor at 60 ° C. Add 1.8 g of silicon dioxide (Wakogel 60N 63-212 μm), 55 g of ethanol, 25 g of hexane, and 0.16 g of potassium hydroxide in the autoclave, and add argon gas from the cylinder at a temperature of 25 ° C. with a pressure gauge. At the pressure indicated by (Swagelok FST PGC-50M-MG10), the autoclave was filled to 0.50 MPa, held for 10 minutes with stirring, and sealed. Then, the inside of the autoclave was heated to 200 ° C. while stirring at 500 rpm, and the mixture was reacted for 6 hours. The yield of tetraethoxysilane based on silica was 46.0%. The reaction results are shown in Table 1.

<Comparative Example 1>
Tetramethoxysilane was produced by the same operation as in Example 1 except that the amount of methanol was 8.0 g and no aliphatic hydrocarbon solvent was added to the reaction conditions of Example 1. The yield of tetramethoxysilane based on silicon dioxide was 9%. The results are shown in Table 1.

<Comparative Example 2>
Tetramethoxysilane was produced by the same operation as in Example 8 except that the amount of methanol was 5.6 g and no aliphatic hydrocarbon solvent was added to the reaction conditions of Example 8. The yield of tetramethoxysilane based on silicon dioxide was 45%. The results are shown in Table 1.

<Comparative Example 3>
Tetraethoxysisilane was produced by the same operation as in Example 11 except that the amount of ethanol was 5.6 g and no aliphatic hydrocarbon solvent was added to the reaction conditions of Example 11. The yield of tetraethoxysilane based on silicon dioxide was 30%. The results are shown in Table 1.

<Comparative Example 4>
Tetraethoxysisilane was produced by the same operation as in Example 12 except that ethanol was 80 g and no aliphatic hydrocarbon solvent was added to the reaction conditions of Example 12. The yield of tetraethoxysilane based on silicon dioxide was 17%. The results are shown in Table 1.

Comparison between Examples 1 to 7 and Comparative Example 1, comparison between Examples 8 to 9 and Comparative Example 2, comparison between Examples 10 to 11 and Comparative Example 3, and comparison between Example 12 and Comparative Example 4. From this, it can be seen that the yield of tetraalkoxysilane is improved by reacting alcohol and silicon oxide in the presence of the aliphatic hydrocarbon solvent by using the aliphatic hydrocarbon solvent. Further, from the comparison between Examples 10 to 11 and Comparative Example 3 and the comparison between Example 12 and Comparative Example 4, the yield of tetraalkoxysilane was increased even when the reaction scale was increased by using the aliphatic hydrocarbon solvent. It can be seen that the rate improves.

This application is based on a Japanese patent application filed on December 26, 2017 (Japanese Patent Application No. 2017-249517), the contents of which are incorporated herein by reference.

According to the production method of the present invention, tetraalkoxysilane used as a raw material for producing various silane compounds, organic silicone polymers, various silylating agents, colloidal silica, ceramics and the like can be produced with high efficiency.

101a, 101b Equipment that can be used in the production method of the present invention 102 Alcohol 103 Silicon oxide 104 Vaporizing component of reaction mixture 105 Molecular sieve 106 Reactor for first step 107 Container for second step 108 Vaporizing component of reaction mixture Outbound flow path for movement 109 Return flow path for movement of components in contact with the molecular sieve 110 Connection between the container for the second process and the outbound flow path

Claims (3)

It comprises a first step of reacting an alcohol with silicon oxide in the presence of an aliphatic hydrocarbon solvent, and a second step of bringing the vaporized component of the reaction mixture obtained in the first step into contact with the molecular sieve .
The aliphatic hydrocarbon solvent is selected from aliphatic hydrocarbons having 5 to 10 carbon atoms.
The molecular sieve is present in the reactor performing the first step at a position where it does not come into contact with the liquid component and / or the solid component of the reaction mixture, whereby the first step and the second step are combined into one container. A method for producing tetraalkoxysilane , which proceeds in the process. The first step of reacting alcohol and silicon oxide in the presence of an aliphatic hydrocarbon solvent, and
The second step of bringing the vaporized component of the reaction mixture obtained in the first step into contact with the molecular sieve is included.
The aliphatic hydrocarbon solvent is selected from aliphatic hydrocarbons having 5 to 10 carbon atoms.
The molecular sieve is present in a container that performs the second step, which is different from the reactor that performs the first step, and an outward flow path for the vaporizing component to move from the reactor to the container and the molecular sieve. The first step and the second step proceed by connecting the reactor and the container via a return flow path for moving the component in contact with the reactor from the container to the reactor. A method for producing an alkoxysilane. The method for producing a tetraalkoxysilane according to claim 1 or 2 , wherein the first step is carried out in the presence of an alkali metal compound and / or an alkaline earth metal compound.

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