JP2002029733A - Method for manufacturing spherical porous body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a spherical porous body by which a spherical porous body can be obtained with a high production yield and the uniformity of the particle size of the porous body can be improved. SOLUTION: A solution containing a 0.001 to 0.027 mol/L surfactant expressed by general formula (1), 0.01 to 0.25 mol/L silica source material and water is made to react under basic conditions. The mol number of the surfactant is controlled to >=1/10 of the mol number of the silicon atoms in the silica source material. In formula, each of R1 to R3 is an alkyl group, X is a halogen atom and n is an integer of 8 to 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a spherical porous body, and more particularly, to a method for producing a spherical porous body capable of increasing the content ratio of the spherical porous body and the uniformity of the particle diameter of the spherical porous body. About the method.

[0002]

2. Description of the Related Art Since it has been found that a silica-based porous body having 1.5 to 50 nm diameter mesopores arranged very regularly can be obtained from a specific silica raw material and a surfactant (for example, CT Kresge et al., Nature, vol. 359, p710,
1992, S. Inagaki et al., J. Chem. Soc., Chem. Commu
n., 680, 1993, etc.), and studies on synthesis and functional development of ordered mesoporous materials have been actively conducted.

For example, Anderson et al., When a tetramethoxysilane is reacted in a water / methanol solution containing a surfactant such as cetyltrimethylammonium bromide and sodium hydroxide to obtain a porous material, methanol is added to a specific concentration. It is reported that a porous body can be easily obtained at room temperature by using the method (MT Andersonet
al., Chem. Mater. 10, 1490-1500, 1998). JP-A-10-328558 discloses that a spherical porous body can be obtained by reacting alkoxysilane under an acidic condition in an aqueous solution containing a surfactant such as an alkyltrimethylammonium salt. I have.

[0004]

SUMMARY OF THE INVENTION However, Anders
The porous material obtained by the method of on et al. is a mixture of fibrous, spindle-shaped (spheroidal), and spherical porous materials, and is inferior in shape uniformity. It is difficult to increase the density and the density of a compression-molded product obtained by compacting a porous body, and for example, there is a problem that the adsorption capacity per unit volume when used as an adsorbent cannot be increased. .

According to the method disclosed in Japanese Patent Application Laid-Open No. 10-328558, a spherical porous body can be obtained. In some cases, the porous body was partially obtained, or the variation in the particle size became large. In addition, the stability over time such as the moisture resistance of the porous body may be poor.

The present invention has been made in view of the above-mentioned problems of the prior art, and can provide a porous body having a spherical shape at a high ratio, and further improves the uniformity of the particle diameter of the porous body. It is an object of the present invention to provide a method for producing a spherical porous body that can perform the method.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, using an alkylammonium halide having a specific structure as a surfactant, this surfactant and a silica raw material were used. By a method of dissolving in water to a specific concentration and reacting under basic conditions, a spherical porous body can be obtained at a high ratio in shape, and further,
It has been found that the uniformity of the particle size of the porous body can be improved.

That is, the present invention relates to a method for producing a spherical porous body, which comprises reacting a silica raw material under a basic condition in a solution containing a silica raw material, a surfactant and water, wherein the surfactant is An alkylammonium halide represented by the following general formula (1), wherein the concentration of the surfactant is 0.001 to 0.027 mol based on the total volume of the solution.
/ L, the concentration of the silica raw material is 0.01 to 0.25 mol / L based on the total volume of the solution, and the number of moles of the surfactant is the number of silicon atoms in the silica raw material. It is intended to provide a method characterized by being 1/10 or more of the number of moles.

[0009]

Embedded image [Wherein R ¹ , R ² and R ³ are the same or different and may be an alkyl group having 1 to 3 carbon atoms, X is a halogen atom, n
Represents an integer of 8 to 14, respectively. In the present invention, as described above, an alkylammonium halide having a long-chain alkyl group having 9 to 15 carbon atoms is used as a surfactant, and the surfactant and the silica raw material are adjusted to have the above-described concentration and ratio. Dissolving in water and reacting under basic conditions, it is possible to obtain a porous material having a spherical shape at a high ratio, and it is possible to further improve the uniformity of the particle size of the obtained porous material. Become.

In the present invention, the surfactant is decyltrimethylammonium halide, and the concentration of the surfactant is 0.01 to 10% based on the total volume of the solution.
0.02 mol / L, and the concentration of the silica raw material was 0.02 to 0.02 based on the total volume of the solution.
It is preferably 3 mol / L. Further, the surfactant is dodecyltrimethylammonium halide, the concentration of the surfactant is 0.01 to 0.02 mol / L based on the total volume of the solution, and the concentration of the silica raw material is It is preferably 0.02 to 0.03 mol / L based on the total volume of the solution.
When the surfactants described above are used and the concentration of the surfactant and the silica raw material is within the above range, the uniformity of the particle diameter of the obtained spherical porous body tends to be particularly excellent.

[0011] In the present invention, the silica raw material is at least one selected from the group consisting of alkoxysilane, sodium silicate, layered silicate and silica.
It is preferable to use two silica raw materials. By using the above-mentioned silica raw material, the ratio of the spherical porous body and the uniformity of the particle diameter tend to be higher.

[0012]

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a spherical porous material, which comprises reacting a silica raw material under a basic condition in a solution containing a silica raw material, a surfactant and water. The agent is an alkyl ammonium halide represented by the following general formula (1), and the concentration of the surfactant is 0.001 to 0.027 mol /% based on the total volume of the solution.
L, the concentration of the silica raw material is 0.01 to 0.25 mol / L based on the total volume of the solution, and the number of moles of the surfactant is the number of moles of silicon atoms in the silica raw material. It is characterized by being at least 1/10 of the number.

[0013]

Embedded image [Wherein R ¹ , R ² and R ³ are the same or different and may be an alkyl group having 1 to 3 carbon atoms, X is a halogen atom, n
Represents an integer of 8 to 14, respectively. The silica raw material used in the present invention is not particularly limited as long as it can form a silicon oxide (including a silicon double oxide) by reaction, but from the viewpoint of reaction efficiency and physical properties of the obtained silicon oxide. , Alkoxysilane, sodium silicate, layered silicate, silica, or an arbitrary mixture thereof is preferably used.

As the alkoxysilane, tetraalkoxysilane having four alkoxy groups, trialkoxysilane having three alkoxy groups, and dialkoxysilane having two alkoxy groups can be used. Although the type of the alkoxy group is not particularly limited, those having a relatively small number of carbon atoms in the alkoxy group (such as about 1 to 4 carbon atoms) such as a methoxy group, an ethoxy group, a propoxy group, and a butoxy group This is advantageous in terms of reactivity.
When the alkoxysilane has three or two alkoxy groups, an organic group, a hydroxyl group, or the like may be bonded to the silicon atom in the alkoxysilane, and the organic group may be an amino group, a mercapto group, or the like. It may further have a functional group.

Examples of the tetraalkoxysilane that can be used in the present invention include tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, tetrabutoxysilane, dimethoxydiethoxysilane and the like. Silanol, triethoxysilanol, trimethoxymethylsilane, trimethoxyvinylsilane, triethoxyvinylsilane, triethoxy-3-glycidoxypropylsilane, 3-mercaptopropyltrimethoxysilane, 3-chloropropyltrimethoxysilane, 3- (2
-Aminoethyl) aminopropyltrimethoxysilane,
Examples include phenyltrimethoxysilane, phenyltriethoxysilane, γ- (methacryloxypropyl) trimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and the like. Examples of the dialkoxysilane include dimethoxydimethylsilane, diethoxydimethylsilane, diethoxy-3-glycidoxypropylmethylsilane, dimethoxydiphenylsilane, dimethoxymethylphenylsilane, and the like.

In the present invention, the above alkoxysilane is
They can be used alone or in combination of two or more. The alkoxysilane having 2 to 4 alkoxy groups has one alkoxy group.
It is also possible to use in combination with a monoalkoxysilane. Examples of the monoalkoxysilane that can be used in this manner include trimethylmethoxysilane, trimethylethoxysilane, and 3-chloropropyldimethylmethoxysilane.

Alkoxysilanes produce silanol groups by hydrolysis, and the silanol groups formed condense to form silicon oxide. In this case, an alkoxysilane having a large number of alkoxy groups in the molecule has many bonds generated by hydrolysis and condensation. Therefore, in the present invention, it is preferable to use tetraalkoxysilane having many alkoxy groups as the alkoxysilane, and as the tetraalkoxysilane, it is particularly preferable to use tetramethoxysilane from the viewpoint of the reaction rate.

In the present invention, sodium silicate used as a silica raw material includes sodium metasilicate (Na ₂ SiO ₃ ) and sodium orthosilicate (Na ₄ S).
iO ₄ ), sodium disilicate (Na ₂ Si ₂ O ₅ ), sodium tetrasilicate (Na ₂ Si ₄ O ₉ ), and the like. As the sodium silicate, in addition to such a single substance, a substance whose composition is different depending on the case, such as water glass (Na ₂ O · nSiO ₂ , n = 2 to 4), may be used.

As the layered silicate, kanemite (N
aHSi_TwoO_Five・ 3H_TwoO), sodium disilicate crystals
(Α, β, γ, δ-Na_TwoSi_TwoO_Five), Macatite (N
a_TwoSi _FourO₉・ 5H_TwoO), ialite (Na)_TwoSi₈O
₁₇・ XH_TwoO), magadiite (Na_TwoSi₁₄O₁₇・ X
H_TwoO), Kenyaite (Na_TwoSi₂₀O₄₁・ XH_TwoO) etc.
Is mentioned. Also, sepiolite, montmorillonai
G, vermiculite, mica, kaolinite, smecta
Of clay minerals such as silica
The one with the element removed can also be used as a layered silicate.
is there.

The silica used as a silica raw material in the present invention includes Ultrasil (Ultrasil), Cab-O-Si
l (Cabot), precipitated silica such as HiSil (Pittsburgh Plate Glass); colloidal silica; Aerosil (Degussa
-Huls).

The above silica raw materials can be used alone or in combination of two or more. When two or more kinds of silica raw materials are used, reaction conditions at the time of producing a spherical porous body may be complicated,
In the present invention, the silica raw material is preferably used alone.

The surfactant used in the present invention includes:
It is represented by the following general formula (1).

[0023]

Embedded image [Wherein R ¹ , R ² and R ³ are the same or different and may be an alkyl group having 1 to 3 carbon atoms, X is a halogen atom, n
Represents an integer of 8 to 14, respectively. R ¹ , R ² , and R ³ in the general formula (1) may be the same or different, but are preferably the same from the viewpoint of the symmetry of the surfactant molecule. When the symmetry of surfactant molecules is excellent, aggregation of surfactants (such as formation of micelles)
Tends to be easier. Further, at least one of R ¹ , R ² and R ³ is preferably a methyl group,
More preferably, all of R ¹ , R ² and R ³ are methyl groups. Further, n in the general formula (1) is preferably an integer of 9 to 13, and more preferably 9, 11, or 13. The type of halogen atom of X is not particularly limited, but from the viewpoint of availability, X is preferably a chlorine atom or a bromine atom.

Therefore, it is represented by the above general formula (1).
As the surfactant, R¹, R^Two, R ^ThreeAre all methyl groups
Is an alkyltrimethylammonium halide
Is preferred. Alkyl trimethyl ammonium halas
As the id, decyltrimethylammonium halide
Do, dodecyltrimethylammonium halide, tetra
Decyltrimethylammonium halide is preferred. What
Even, decyl trimethyl ammonium halide, dode
Siltrimethylammonium halide is particularly preferred.
Decyl as decyltrimethylammonium halide
Trimethylammonium chloride, decyltrimethyla
Ammonium bromide is preferred, and dodecyltrimethyla
Dodecyl trimethylammonium halide
Ium chloride, dodecyltrimethylammonium bromide
Mid is preferred.

Such a surfactant forms a complex with silica raw material in water. The silica raw material in the composite is converted into silicon oxide by the reaction, but since silicon oxide is not generated in the part where the surfactant is present, pores are formed in the part where the surfactant is present. Will be. That is, the surfactant functions as a template for pore formation. In the present invention, the surfactant can be used alone or in combination of two or more. However, as described above, the surfactant acts as a template when pores are formed in the reaction product of the silica raw material,
Since the type greatly affects the shape of the pores of the porous body, it is preferable to use only one type of surfactant in order to obtain a more uniform spherical porous body.

In the present invention, the silica raw material is reacted under a basic condition in a solution containing the above-mentioned silica raw material, a surfactant and water. The silica raw material generally undergoes a reaction under both basic conditions and acidic conditions and changes to silicon oxide, but the silica raw material and the concentration of the surfactant in the present invention are considerably lower than those of the prior art method. The reaction hardly proceeds under acidic conditions. Therefore, in the present invention, it is necessary to react the silica raw material under basic conditions. In addition,
The silica raw material has a higher number of reaction points of silicon atoms when reacted under basic conditions than when reacted under acidic conditions, and can provide a silicon oxide having excellent properties such as moisture resistance and heat resistance. Therefore, the method of the present invention is also advantageous in this respect.

In order to make the above solution basic, usually,
A basic substance such as an aqueous sodium hydroxide solution is added. The basic conditions at the time of the reaction are not particularly limited, but the value obtained by dividing the alkali equivalent of the basic substance to be added by the number of moles of silicon atoms in the total silica raw material is 0.1 to 0.9. preferable. This value is more preferably 0.2 to 0.5. When the value obtained by dividing the alkali equivalent of the basic substance to be added by the number of moles of silicon atoms in the total silica material is less than 0.1, the yield tends to be extremely reduced, and exceeds 0.9. In such a case, it tends to be difficult to form a porous body.

In the present invention, the concentration of the above-mentioned surfactant is set to 0.001 to 0.
027 mol / L, and the concentration of the above silica raw material is 0.01 to 0.25 mol based on the total volume of the above solution.
/ L, and the number of moles of the surfactant is 1/10 or more of the number of moles of silicon atoms in the silica raw material.

In the present invention, by strictly controlling the concentrations and ratios of the surfactant and the silica raw material as described above, it is possible to obtain a porous material having a spherical shape at a high ratio. It is possible to improve the uniformity of the particle size. If the concentration and the ratio are not within the above ranges, for example, if the concentration of the surfactant is 0.0
When the amount is less than 1 mol / L, a porous body cannot be obtained because the amount of a surfactant to be a template is insufficient. On the other hand, when exceeding 0.027 mol / L,
A porous body having a spherical shape cannot be obtained at a high ratio,
The uniformity of the particle size of the porous body also decreases. Further, when the concentration of the silica raw material is less than 0.01 mol / L, the generated particles are very fine, and it is very difficult to recover them.
If it exceeds mol / L, the ratio of the porous body having a spherical shape and the uniformity of the particle diameter of the porous body will be low.

In the present invention, decyltrimethylammonium halide is used as a surfactant, and based on the total volume of a solution containing a silica raw material, a surfactant and water,
The concentration of the surfactant is 0.005 to 0.025 mol / L
And the concentration of the silica raw material is 0.01 to 0.15 mol / L based on the total volume of the solution, and the number of moles of the surfactant is 1/10 of the number of moles of silicon atoms in the silica raw material. As described above, it is preferable to react the silica raw material.

In this case, the concentration of the surfactant is more preferably from 0.005 to 0.02 mol / L, and even more preferably from 0.01 to 0.02 mol / L. The concentration of the silica raw material is 0.01 to 0.1.
mol / L, more preferably 0.01 to 0.1 mol / L.
More preferably, it is 0.05 mol / L,
It is particularly preferable that the concentration be 0.03 mol / L. The concentration of the surfactant is 0.01 to 0.02 mol / L,
And the concentration of the silica raw material is 0.02 to 0.03 mol / L
In the case of, the uniformity of the particle diameter of the obtained spherical porous body becomes particularly high. For example, it is possible to make the particle diameters of all the obtained porous particles fall within a range of ± 20% of the average particle diameter (see Example 4).

In the present invention, dodecyltrimethylammonium halide is used as a surfactant, and the concentration of the surfactant is 0.001 to 0.001 based on the total volume of the solution containing the silica raw material, the surfactant and water. 0.025m
ol / L, the concentration of the silica material is 0.01 to 0.15 mol / L based on the total volume of the solution, and the number of moles of the surfactant is the number of moles of silicon atoms in the silica material. It is preferable that the ratio is 1/10 or more and the silica raw material is reacted.

In this case, the concentration of the surfactant is more preferably from 0.005 to 0.02 mol / L, and even more preferably from 0.01 to 0.02 mol / L. The concentration of the silica raw material is 0.01 to 0.1.
mol / L, more preferably 0.01 to 0.1 mol / L.
More preferably, it is 0.05 mol / L,
It is particularly preferable that the concentration be 0.03 mol / L. The concentration of the surfactant is 0.01 to 0.02 mol / L,
And the concentration of the silica raw material is 0.02 to 0.03 mol / L
In the case of, the uniformity of the particle diameter of the obtained spherical porous body becomes particularly high. For example, it is possible to make the particle diameters of all the obtained porous particles fall within a range of ± 20% of the average particle diameter (see Example 2).

In the present invention, as described above, an alkylammonium halide having a long-chain alkyl group having 9 to 15 carbon atoms is used as a surfactant. Instead of the alkyltrimethylammonium halide having 9 to 15 carbon atoms in the alkyl group, the alkyl group has less than 9 carbon atoms or 1 carbon atom.
When an alkyltrimethylammonium halide of more than 5 is used, a spherical porous body cannot be obtained, or even if it is obtained, a porous body having a shape other than a spherical shape is mixed or particle size uniformity is poor. And so on.

As described above, even if an alkyltrimethylammonium halide surfactant having an alkyl group of less than 9 or more than 15 carbon atoms capable of forming a porous body in the prior art, the method of the present invention can form a spherical porous body. What I can't do is
This is considered to be because in the method of the present invention, the concentrations of the silica raw material and the surfactant were considerably lower than those of the prior art method.

In the present invention, the number of moles of the surfactant must be at least 1/10 of the number of moles of silicon atoms in the silica raw material (hereinafter, the number of moles of the surfactant and the number of moles in the silica raw material). Is sometimes referred to as surfactant / Si). As described above, the surfactant acts as a template when pores are formed in the reaction product of the silica raw material, and when the surfactant / Si is less than 1/10, the template is not formed or is not formed. Also becomes unstable, so that a porous body cannot be formed. On the other hand, even when the ratio of surfactant / Si is large, a spherical porous body is formed (however, the concentrations of the surfactant and the silica raw material must be within the above range). This is because the surfactant that did not form a complex with the silica raw material during the reaction can be stably present in the solution as a surplus without affecting the reaction of the silica raw material. In the present invention, surfactant / Si is more preferably 1/5 or more, and from the viewpoint of reducing surplus surfactant, surfactant / Si is 1/5 to 1/1. Is more preferred.

In the method for producing a spherical porous body of the present invention,
The reaction conditions (reaction temperature, reaction time, etc.) of the silica raw material are not particularly limited. The reaction temperature can be, for example, 0 ° C to 100 ° C. In the present invention, it is also possible to add an alcohol such as methanol or another organic solvent as a solvent to a solution containing a silica raw material, a surfactant and water, and in such a case, the reaction temperature is − 20 ° C ~
It can be 100 ° C. The reaction preferably proceeds with stirring. The reaction conditions are preferably determined based on the type of the silica raw material used and the like.

That is, when alkoxysilane is used as a silica raw material, for example, a spherical porous body can be obtained as follows. First, a surfactant and a basic substance are added to water (which may be a mixture of water and an organic solvent such as an alcohol) to prepare a basic solution of the surfactant. Is added.
Since the added alkoxysilane is hydrolyzed (or hydrolyzed and condensed) in the solution, a white powder precipitates in a few seconds to a few minutes after the addition. In this case, the reaction temperature is preferably 0 ° C to 80 ° C, and is preferably 10 ° C to 40 ° C.
Is more preferable. The solution is preferably stirred.

After the precipitate is deposited, the solution is further stirred at 0 ° C. to 80 ° C. (preferably 10 ° C. to 40 ° C.) for 1 hour to 10 days to advance the reaction of the silica raw material. After completion of stirring, if necessary, stabilize the system by leaving it at room temperature overnight,
When the volatile components are removed, a spherical porous body is obtained.

In the case where a porous body is prepared by the above-described process using alkoxysilane, the case where the concentration of the alkoxysilane and the surfactant is within the range of the present invention and the case where the alkoxysilane and the surfactant are When at least one of the concentrations is out of the range of the present invention, the time until the addition of alkoxysilane to the formation of a white precipitate is greatly different. When the concentration is within the range of the present invention, the time until the white precipitate is generated is several times to several tens times longer than when the concentration is outside the range. This phenomenon indicates that the reaction in the present invention until a white precipitate is generated proceeds relatively slowly. While we do not wish to be bound by any theory,
It is considered that such a reduction in the rate of the reaction suppresses variations in the shape and the like between the porous particles.

When a silica raw material (sodium silicate, layered silicate or silica) other than alkoxysilane is used as the silica raw material, the silica raw material is added to water (which may be a mixture of water and an organic solvent such as alcohol). Then, a basic substance such as an aqueous sodium hydroxide solution is further added to prepare a uniform solution so as to be about equimolar to the silicon atoms in the silica raw material, and then the diluted acid solution is added to the silicon atoms in the silica raw material. A spherical porous body can be produced by a method of adding ２〜 to ／ times the molar amount of the porous material. An excess of the basic substance is required for the purpose of breaking a part of the Si— (O—Si) ₄ bond already formed in the silica raw material, and the excess must be neutralized with an acid. There is. As the acid, any of inorganic acids such as hydrochloric acid and sulfuric acid and organic acids such as acetic acid may be used.

In the present invention, the formation mechanism of the spherical porous material differs between the case where the non-layered silica raw material (alkoxysilane, sodium silicate and silica) is used as the silica raw material and the case where the layered silica raw material (layered silicate) is used. it is conceivable that.

When a non-layered silica raw material is used, the following mechanism for forming a spherical porous body can be considered. First, by adding a surfactant to water, the surfactant forms micelles regularly arranged in water. When the non-lamellar silica raw material is added to the aqueous solution in which micelles are formed, the non-lamellar silica raw material aggregates around the surfactant to form a composite (typically, a honeycomb-like composite). And
Under the basic conditions, the non-lamellar silica raw material reacts around the surfactant and changes into silicon oxide. Therefore, since silicon oxide is not formed in the portion where the surfactant formed micelles, the reaction product is a porous body (typically, a spherical porous body having honeycomb-shaped pores).

On the other hand, when a layered silicate, which is a layered silica raw material, is used as the silica raw material, the following formation mechanism of a spherical porous body is considered. That is, when the layered silicate is added to the aqueous solution of the surfactant, the surfactant enters between the layers of the layered silicate to form a composite (typically, a honeycomb-shaped composite). At this time, the adjacent layers of the layered silicate are not bonded, but the adjacent layers are bonded by the progress of the reaction of the layered silicate under basic conditions. Thereby, a spherical porous body (typically, a spherical porous body in which holes are formed in a honeycomb shape) is formed such that a portion where the surfactant was present becomes a hole.

According to the production method of the present invention, it is considered that the reaction of the silica raw material proceeds by the above-mentioned reaction mechanism, and the obtained spherical porous body has a surfactant inside the pores. The spherical porous body can be used for various applications even in a state where a surfactant is present inside the pores. However, when used for an application requiring a large specific surface area, the surfactant may be removed.

As a method for removing the surfactant from the porous material, for example, a method of firing, a method of treating with an organic solvent, an ion exchange method and the like can be mentioned. In the firing method, the porous body is heated at 300 to 1000C, preferably 400 to 700C. The heating time may be about 30 minutes, but it is preferable to heat for 1 hour or more to completely remove the surfactant. Although calcination can be performed in the air, since a large amount of combustion gas is generated, an inert gas such as nitrogen may be introduced.

In the case of treatment with an organic solvent, the porous body is immersed in a good solvent of the used surfactant to extract the surfactant. In the ion exchange method, the porous body is immersed in an acidic solution (such as ethanol containing a small amount of hydrochloric acid), for example, 50-70.
Stir while heating at ° C. Thereby, the surfactant existing in the pores of the porous body is ion-exchanged with hydrogen ions. Although hydrogen ions remain in the holes due to ion exchange, the problem of blockage of the holes does not occur because the ionic radius of the hydrogen ions is sufficiently small.

According to the method of the present invention described above, a porous body having a regular pore array structure can be obtained. The pore array structure may be two-dimensional hexagonal, three-dimensional hexagonal, or cubic. In the present invention, the surfactant used has the chemical structure represented by the general formula (1), and the silica raw material is reacted under the above conditions. A spherical porous body arranged in a two-dimensional hexagonal is easily obtained. Also,
Although the average particle size of the spherical porous body obtained by the method of the present invention is not particularly limited, the average particle size is preferably from 0.1 to 5 μm, and more preferably from 0.2 to 1 μm.
The average particle diameter of the spherical porous body can be changed by the concentration of the surfactant and the silica raw material, the temperature during the reaction, the stirring state, and the like.

As described above, according to the method of the present invention, a porous body having a spherical shape can be obtained at a high ratio, and the uniformity of the particle diameter of the porous body can be improved. . Therefore, the porous body obtained in the present invention is uniform in shape and particle size without performing classification by a sieve or the like, the filling rate when filled in a container, and the compression molded product obtained by compacting. It is possible to increase the density. Therefore,
It can be particularly suitably used as an adsorbent, a dielectric, a filler, and the like.

[0050]

Hereinafter, preferred embodiments of the present invention will be described in more detail, but the present invention is not limited to these embodiments.

[Preparation of Porous Material Using Dodecyltrimethylammonium Bromide] (Example 1) 747 mL of water and 250 mL of methanol
Was added to 1.54 g of dodecyltrimethylammonium bromide (surfactant) and 3.28 mL of 1 N sodium hydroxide, and the mixture was stirred until it became uniform. To this, tetramethoxysilane (silica raw material)
When 9 g was added and stirring was continued, tetramethoxysilane was completely dissolved, and a white powder was deposited after about 60 seconds. The concentration of dodecyltrimethylammonium is 0.005 mol based on the total volume of all the above components (water, methanol, dodecyltrimethylammonium, 1N sodium hydroxide and tetramethoxysilane).
/ L, and the concentration of tetramethoxysilane is 0.012.
It was 5 mol / L. Further, the surfactant / Si is set at 0.1.
It was 4.

After stirring at room temperature for further 8 hours and allowing to stand overnight, filtration and washing with deionized water were repeated three times to obtain a white powder. The white powder was dried with a hot air drier for 3 days, and then calcined at 550 ° C. for 6 hours to remove the organic components including the surfactant and obtain a porous body. X of this porous body
The line diffraction pattern is shown in FIG. The X-ray diffraction pattern shown in FIG. 1 showed that the obtained porous body had a two-dimensional hexagonal pore array structure. Next, the porous body was observed with an electron microscope. As a result, each of about 100 porous bodies observed by an electron microscope had a spherical shape, and the particle size was 0.65 to 1.27.
μm. FIG. 2 shows an electron micrograph of the porous body according to the present example taken at a magnification of 5,000. In FIG. 2, the black spherical portion indicates the porous body obtained in this example.

Example 2 To a mixed solution of 742 mL of water and 250 mL of methanol were added 4.62 g of dodecyltrimethylammonium bromide (surfactant) and 7.86 mL of 1N sodium hydroxide, and the mixture was stirred until it became uniform. did. When 4.55 g of tetramethoxysilane (silica raw material) was added thereto and stirring was continued, the tetramethoxysilane was completely dissolved, and a white powder was precipitated after about 60 seconds. The concentration of dodecyltrimethylammonium based on the total volume of all the above components (water, methanol, dodecyltrimethylammonium, 1N sodium hydroxide and tetramethoxysilane) was 0.015 mol / L, Was 0.0299 mol / L. The ratio of surfactant / Si was 0.5.

After stirring at room temperature for further 8 hours and leaving overnight, filtration and washing with deionized water were repeated three times to obtain a white powder. The white powder was dried with a hot air drier for 3 days, and then calcined at 550 ° C. for 6 hours to remove the organic components including the surfactant and obtain a porous body. X of this porous body
The line diffraction pattern showed that the obtained porous body had a two-dimensional hexagonal pore array structure. Next, the porous body was observed with an electron microscope. as a result,
The particle diameter of 100 arbitrary porous bodies observed by an electron microscope was in the range of 0.625 to 0.75 μm, and the average particle diameter was 0.63 μm. In addition, the average particle diameter is ± 19.
%, The particle diameters of all the particles were in the range, and it was shown that a spherical porous body having a very narrow particle diameter distribution and a very excellent particle diameter uniformity was obtained. FIG. 3 shows an electron micrograph of the porous body according to the present example taken at a magnification of 10,000 times. In FIG. 3, a black spherical portion indicates the porous body obtained in this example.

Comparative Example 1 To a mixed solution of 727 mL of water and 250 mL of methanol were added 17 g of dodecyltrimethylammonium bromide (surfactant) and 22.8 mL of 1N sodium hydroxide, and the mixture was stirred until uniform. When 13.2 g of tetramethoxysilane (silica raw material) was added thereto and stirring was continued, the tetramethoxysilane was completely dissolved, and a white powder was precipitated after about 2 seconds. All the above components (water, methanol,
Dodecyltrimethylammonium, based on the total volume of 1N sodium hydroxide and tetramethoxysilane), the concentration of dodecyltrimethylammonium was 0.05.
It was 5 mol / L and the concentration of tetramethoxysilane was 0.0867 mol / L. In addition, surfactant /
Si was 0.63.

After stirring at room temperature for an additional 8 hours and allowing to stand overnight, filtration and washing with deionized water were repeated three times to obtain a white powder. The white powder was dried with a hot air drier for 3 days, and then calcined at 550 ° C. for 6 hours to remove the organic components including the surfactant and obtain a porous body. X of this porous body
The line diffraction pattern showed that the obtained porous body had a two-dimensional hexagonal pore array structure. Next, the porous body was observed with an electron microscope. In FIG.
The electron micrograph of the porous body by this comparative example taken at 10000 times magnification is shown. As shown in FIG. 4, the shape of the porous body obtained in this comparative example was a rice grain.

[Preparation of Porous Material Using Decyltrimethylammonium Bromide] (Example 3) 745 mL of water and 250 mL of methanol
Was mixed with 7 g of decyltrimethylammonium bromide (surfactant) and 5.7 mL of 1 N sodium hydroxide, and the mixture was stirred until it became uniform. When 3.3 g of tetramethoxysilane (silica raw material) was added thereto and stirring was continued, the tetramethoxysilane was completely dissolved, and a white powder was precipitated after about 10 seconds. In addition,
The concentration of decyltrimethylammonium based on the total volume of all the above components (water, methanol, decyltrimethylammonium, 1N sodium hydroxide and tetramethoxysilane) is 0.025 mol / L, and the concentration of tetramethoxysilane Was 0.0217 mol / L. Further, surfactant / Si was 1.15.

After stirring at room temperature for further 8 hours and allowing to stand overnight, filtration and washing with deionized water were repeated three times to obtain a white powder. The white powder was dried with a hot air drier for 3 days, and then calcined at 550 ° C. for 6 hours to remove the organic components including the surfactant and obtain a porous body. X of this porous body
The line diffraction pattern showed that the obtained porous body had a two-dimensional hexagonal pore array structure. Next, the porous body was observed with an electron microscope. as a result,
Each of about 100 porous bodies observed by an electron microscope has a spherical shape, and the particle size is 0.2 to
0.9 μm.

Example 4 3.84 g of decyltrimethylammonium bromide (surfactant) and 1 part of 745 mL of water and 250 mL of methanol were mixed.
5.7 mL of normal sodium hydroxide was added and stirred until uniform. When 3.3 g of tetramethoxysilane (silica raw material) was added thereto and stirring was continued, the tetramethoxysilane was completely dissolved, and a white powder was deposited after about 50 seconds. All the above components (water, methanol,
Decyltrimethylammonium, based on the total volume of 1N sodium hydroxide and tetramethoxysilane), the concentration of decyltrimethylammonium was 0.013.
7 mol / L, and the concentration of tetramethoxysilane was 0.0217 mol / L. In addition, surfactant /
Si was 0.63.

After stirring at room temperature for an additional 8 hours and allowing to stand overnight, filtration and washing with deionized water were repeated three times to obtain a white powder. The white powder was dried with a hot air drier for 3 days, and then calcined at 550 ° C. for 6 hours to remove the organic components including the surfactant and obtain a porous body. X of this porous body
The line diffraction pattern showed that the obtained porous body had a two-dimensional hexagonal pore array structure. Next, the porous body was observed with an electron microscope. as a result,
The particle size of 100 arbitrary porous bodies observed by an electron microscope was in the range of 0.74 to 0.9 μm, and the average particle size was 0.89 μm. Further, the particle diameters of all the particles were within the range of ± 17% of the average particle diameter, and a spherical porous body having a very narrow particle diameter distribution and a very excellent particle diameter uniformity was obtained. It has been shown. FIG. 5 shows an electron micrograph of the porous body according to the present example taken at a magnification of 5,000.
In FIG. 5, a black spherical portion indicates the porous body obtained in this example.

(Comparative Example 2) To a mixed solution of 745 mL of water and 250 mL of methanol, 8.4 g of decyltrimethylammonium bromide (surfactant) and 5.7 mL of 1 N sodium hydroxide were added, and the mixture was stirred until uniform. did. When 3.3 g of tetramethoxysilane (silica raw material) was added thereto and stirring was continued, the tetramethoxysilane was completely dissolved, and a white powder was deposited after about 6 seconds. In addition, based on the total volume of all the above components (water, methanol, decyltrimethylammonium, 1N sodium hydroxide and tetramethoxysilane),
The concentration of decyltrimethylammonium is 0.03mol
/ L, and the concentration of tetramethoxysilane is 0.021.
It was 7 mol / L. Further, the surfactant / Si is set at 1.
38.

After stirring at room temperature for further 8 hours and allowing to stand overnight, filtration and washing with deionized water were repeated three times to obtain a white powder. The white powder was dried with a hot air drier for 3 days, and then calcined at 550 ° C. for 6 hours to remove the organic components including the surfactant and obtain a porous body. X of this porous body
The line diffraction pattern showed that the obtained porous body had a two-dimensional hexagonal pore array structure. Next, the porous body was observed with an electron microscope. as a result,
It was found that a sheet-like porous body was formed by mixing with the spherical porous body.

Comparative Example 3 To a mixed solution of 636 mL of water and 250 mL of methanol, 77 g of decyltrimethylammonium bromide (surfactant) and 114 mL of 1 N sodium hydroxide were added and stirred until uniform. Add tetramethoxysilane (silica raw material)
When 66 g was added and stirring was continued, tetramethoxysilane was completely dissolved, and a white powder was precipitated after about 2 seconds. The concentration of decyltrimethylammonium was 0.275 mol / L based on the total volume of all the above components (water, methanol, decyltrimethylammonium, 1N sodium hydroxide and tetramethoxysilane).
And the concentration of tetramethoxysilane is 0.434 mo
1 / L. Further, surfactant / Si was 0.63.

After stirring at room temperature for another 8 hours and allowing to stand overnight, filtration and washing with deionized water were repeated three times to obtain a white powder. The white powder was dried with a hot air drier for 3 days, and then calcined at 550 ° C. for 6 hours to remove the organic components including the surfactant and obtain a porous body. X of this porous body
The line diffraction pattern showed that the obtained porous body had a two-dimensional hexagonal pore array structure. Next, the porous body was observed with an electron microscope. as a result,
It was found that an amorphous porous body was formed.

[Preparation of Porous Material Using Hexadecyltrimethylammonium Bromide] (Comparative Example 4) 744 mL of water and 250 mL of methanol
Was mixed with 5 g of hexadecyltrimethylammonium bromide (surfactant) and 5.7 mL of 1 N sodium hydroxide, and the mixture was stirred until the mixture became homogeneous. To this, tetramethoxysilane (silica raw material) 3.3
g was added and stirring was continued, but the solution remained transparent and no precipitate was obtained. In addition, all the above components (water,
Methanol, hexadecyltrimethylammonium, 1
The concentration of hexadecyltrimethylammonium was 0.014 mol / L and the concentration of tetramethoxysilane was 0.0217 mol / L, based on the total volume of normal sodium hydroxide and tetramethoxysilane).
Further, surfactant / Si was 0.65.

[Preparation of Porous Body Under Acidic Conditions] (Comparative Example 5) 742 mL of water and 250 mL of methanol
Was added to the mixed solution of 4.62 g of dodecyltrimethylammonium bromide (surfactant) and 7.86 mL of 1N hydrochloric acid, and the mixture was stirred until the mixture became homogeneous. When 4.55 g of tetramethoxysilane (silica raw material) was added thereto and stirring was continued, the solution remained transparent and no precipitate was obtained. The concentration of dodecyltrimethylammonium based on the total volume of all the above components (water, methanol, dodecyltrimethylammonium, 1N hydrochloric acid and tetramethoxysilane) is 0.015mo.
1 / L, and the concentration of tetramethoxysilane is 0.02.
It was 99 mol / L. The ratio of surfactant / Si was 0.5.

[0067]

As described above, according to the present invention,
It is possible to provide a method for producing a spherical porous body capable of obtaining a spherical porous body at a high ratio and further improving the uniformity of the particle diameter of the porous body.

[Brief description of the drawings]

FIG. 1 is a view showing an X-ray diffraction pattern of a spherical porous body obtained in Example 1.

FIG. 2 is an electron micrograph of the spherical porous body obtained in Example 1 (magnification: 5000).

FIG. 3 is an electron micrograph of the spherical porous body obtained in Example 2 (magnification: 10,000 times).

FIG. 4 is an electron micrograph of the porous body obtained in Comparative Example 1 (at a magnification of 10000).

FIG. 5 is an electron micrograph of the spherical porous body obtained in Example 4 (magnification: 5000).

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yoshiaki Fukushima 41-1, Oku-cho, Yokomichi, Nagakute-cho, Aichi-gun, Aichi F-term in Toyota Central R & D Laboratories, Inc. (reference) 4G073 BC02 BD11 FA11 FB11 FB19 FB42 FC05 FD18 FD20 FD23 GA03 GA11 UA06

Claims (4)

[Claims] 1. A method for producing a spherical porous body, comprising reacting a silica raw material under a basic condition in a solution containing a silica raw material, a surfactant and water, wherein the surfactant has the following general formula ( 1) The concentration of the surfactant is 0.001 to 0.027 based on the total volume of the solution.
mol / L, the concentration of the silica raw material is 0.01 to 0.25 mol / L based on the total volume of the solution, and the number of moles of the surfactant is determined based on the number of silicon atoms in the silica raw material. Is 1/10 or more of the number of moles. Embedded image [Wherein R ¹ , R ² and R ³ are the same or different and may be an alkyl group having 1 to 3 carbon atoms, X is a halogen atom, n
Represents an integer of 8 to 14, respectively. ] 2. The surfactant is decyltrimethylammonium halide, and the concentration of the surfactant is 0.01 to 0.02 mol /% based on the total volume of the solution.
The method according to claim 1, wherein the concentration of the silica raw material is 0.02 to 0.03 mol / L based on the total volume of the solution. 3. The surfactant is dodecyltrimethylammonium halide, and the concentration of the surfactant is 0.01 to 0.02 mol based on the total volume of the solution.
The method according to claim 1, wherein the concentration of the silica raw material is 0.02 to 0.03 mol / L based on the total volume of the solution. 4. The silica raw material is an alkoxysilane,
The method according to any one of claims 1 to 3, wherein the method is at least one silica raw material selected from the group consisting of sodium silicate, layered silicate, and silica.