JP2007197289A - Spherical silica-based mesoporous body, method for producing the same and base catalyst using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spherical silica-based mesoporous body having excellent base catalyst performance. <P>SOLUTION: The spherical silica-based mesoporous body has an average particle diameter of 0.01-3 μm and has radial pores having a median pore diameter of 1-5 nm, wherein the spherical silica-based mesoporous body has been modified with a 3-aminopropyl group. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a spherical silica-based mesoporous material useful as a base catalyst, an adsorbing material and the like, and a method for producing the same.

  Conventionally, use of a base catalyst in which amino groups are introduced into various mesoporous silicas by a method such as grafting or copolymerization has been studied. For example, Japanese Patent Application Laid-Open No. 2003-112051 (Patent Document 1) discloses a base catalyst in which an amino group is directly bonded to a silicon atom of mesoporous silica, and a base catalyst in which an amino group is introduced into FSM-16 is disclosed. Are listed. However, since the FSM used as a support is irregular and has mesopores in the form of rods, there are many outer surfaces, the movement of reactants is limited, and the base catalyst performance is still not sufficient. . In addition, since the amino group is directly bonded to the silicon atom, the possibility that the pores are blocked is low. However, since the ammonia treatment is performed at a high temperature of 200 to 800 ° C., there is a concern about the collapse of the pores. At the same time, there is a problem that other organic functional groups cannot coexist.

  In order to solve such a problem, for example, Japanese Patent Application Laid-Open No. 2005-89218 (Patent Document 2) discloses that a silica raw material and a surfactant are mixed in a solvent, and the surfactant is contained in the silica raw material. A first step of obtaining porous precursor particles in which is introduced, and a second step of obtaining a spherical silica-based mesoporous material by removing the surfactant contained in the porous precursor particles. A method for producing a spherical silica-based mesoporous material that includes a spherical silica-based mesoporous material under specific conditions using a specific surfactant is disclosed. In Patent Document 2, it is described that 3- (2-aminoethyl) aminopropyltrialkoxysilane is used as a silica raw material together with sodium silicate and the like.

However, even the spherical silica-based mesoporous material obtained by the method described in Patent Document 2 does not necessarily have sufficient base catalyst performance.
JP 2003-112051 A JP 2005-89218 A

  The present invention has been made in view of the above-mentioned problems of the prior art, and an object thereof is to provide a spherical silica-based mesoporous material having excellent base catalyst performance and a method for producing the spherical silica-based mesoporous material. And

  As a result of intensive studies to achieve the above object, the present inventors have achieved excellent base catalyst performance by modifying a 3-aminopropyl group in a silica-based mesoporous material having a specific particle morphology and pore morphology. The present inventors have found that a spherical silica-based mesoporous material having the above can be obtained and completed the present invention.

  That is, the spherical silica-based mesoporous material of the present invention is a spherical silica-based mesoporous material having radial pores having an average particle diameter of 0.01 to 3 μm and a central pore diameter of 1 to 5 nm. The spherical silica-based mesoporous material is modified with a 3-aminopropyl group.

  In the spherical silica-based mesoporous material of the present invention, the 3-aminopropyl group is preferably coordinated to Si atoms in the silicate skeleton constituting the spherical silica-based mesoporous material.

  Furthermore, in the spherical silica-based mesoporous material of the present invention, 90% by weight or more of all the particles of the spherical silica-based mesoporous material have a particle size within a range of ± 10% of the average particle size. It is preferable.

The first method for producing a spherical silica-based mesoporous material according to the present invention is a porous precursor particle obtained by mixing a silica raw material and a surfactant in a solvent and introducing the surfactant into the silica raw material. A first step of obtaining
A second step of obtaining a spherical silica-based mesoporous material by removing the surfactant contained in the porous material precursor particles;
A method for producing a spherical silica-based mesoporous material comprising:
At least a part of the silica raw material is an organic alkoxysilane containing a 3-aminopropyl group, and the surfactant is represented by the following general formula (1):

[Wherein R ¹ , R ² and R ³ may be the same or different and each represents an alkyl group having 1 to 3 carbon atoms, X represents a halogen atom, and n represents an integer of 9 to 25, respectively. ]
Is used, an aqueous solvent having an alcohol content of 80% by volume or less is used as the solvent, and the concentration of the surfactant in the solvent is 0.0003 to 0.03 mol / L, In this method, the spherical silica mesoporous material is obtained by adjusting the concentration of the silica raw material to 0.0005 to 0.03 mol / L in terms of Si concentration.

The second method for producing the spherical silica-based mesoporous material of the present invention is a porous precursor obtained by mixing a silica raw material and a surfactant in a solvent and introducing the surfactant into the silica raw material. A first step of obtaining body particles;
A second step of obtaining a spherical silica-based mesoporous material by removing the surfactant contained in the porous material precursor particles;
A third step of graft polymerizing an organic alkoxysilane containing a 3-aminopropyl group to the spherical silica-based mesoporous material;
A method for producing a spherical silica-based mesoporous material containing the following general formula (1) as the surfactant:

[Wherein R ¹ , R ² and R ³ may be the same or different and each represents an alkyl group having 1 to 3 carbon atoms, X represents a halogen atom, and n represents an integer of 9 to 25, respectively. ]
Is used, an aqueous solvent having an alcohol content of 80% by volume or less is used as the solvent, and the concentration of the surfactant in the solvent is 0.0003 to 0.03 mol / L, The spherical silica-based mesoporous material according to any one of claims 1 to 3 is obtained by setting the concentration of the silica raw material to 0.0005 to 0.03 mol / L in terms of Si concentration. It is a method to do.

  The base catalyst of the present invention is characterized by comprising the spherical silica-based mesoporous material.

  According to the present invention, it is possible to provide a spherical silica-based mesoporous material having excellent base catalyst performance and a method for producing the spherical silica-based mesoporous material.

  Hereinafter, the present invention will be described in detail with reference to preferred embodiments thereof.

<Spherical silica-based mesoporous material>
First, the spherical silica-based mesoporous material of the present invention will be described. That is, the spherical silica-based mesoporous material of the present invention is a spherical silica-based mesoporous material having radial pores having an average particle diameter of 0.01 to 3 μm and a central pore diameter of 1 to 5 nm. The spherical silica-based mesoporous material is modified with a 3-aminopropyl group.

  In the spherical silica mesoporous material of the present invention, the spherical silica mesoporous material needs to be modified with a 3-aminopropyl group. As described above, when the spherical silica-based mesoporous material is modified with a 3-aminopropyl group, basic catalytic performance is imparted to the spherical silica-based mesoporous material. In addition, since such a 3-aminopropyl group has a relatively small molecule, the base catalyst performance is hardly deteriorated due to blockage of pores. Furthermore, in the spherical silica mesoporous material of the present invention, it is preferable that such a 3-aminopropyl group is coordinated to Si atoms in the silicate skeleton constituting the spherical silica mesoporous material. Thus, the 3-aminopropyl group is coordinated to the Si atom in the silicate skeleton constituting the spherical silica-based mesoporous material, whereby the base catalyst performance of the spherical silica-based mesoporous material tends to be improved. . In addition, by the 1st manufacturing method (copolymerization method) of the spherical silica type mesoporous material of this invention mentioned later, blockage | closure of a pore is minimized and the said 3-aminopropyl group is more reliably attached to Si in a silicate frame | skeleton. Can be coordinated to an atom.

  Moreover, it is necessary that the average particle diameter of such a spherical silica-based mesoporous material is 0.01 to 3 μm. If the average particle size is less than 0.01 μm, the particles are aggregated, resulting in low reaction efficiency. On the other hand, if it exceeds 3 μm, it becomes difficult to form spherical particles and at the same time it takes time for the reactant to diffuse into the catalyst. The reaction efficiency is lowered. Furthermore, it is preferable that 90% by weight or more of all the particles of the spherical silica-based mesoporous material have a particle size within a range of ± 10% of the average particle size. If the particles having a particle size in the range of ± 10% of the average particle size are less than 90% by weight of the total particles, the aggregation of the particles increases, and the reaction efficiency tends to decrease.

  Further, such a spherical silica-based mesoporous material needs to have radial pores. Since the spherical silica-based mesoporous material has radial pores as described above, the outer surface is reduced and the pores can be effectively used up to the inside. Furthermore, it is necessary that the central pore diameter of such radial pores is 1 to 5 nm. If the central pore diameter is less than 1 nm, sufficient base catalyst performance cannot be exhibited for bulky reactants, while if it exceeds 5 nm, it becomes difficult to form spherical particles.

  The term “spherical” as used in the present invention is not limited to a true sphere, but includes a substantially sphere having a minimum diameter of 80% or more (preferably 90% or more) of the maximum diameter. In the case of a substantially spherical body, the particle size is an average value of the minimum diameter and the maximum diameter in principle. The central pore diameter is a curve (pore diameter distribution curve) in which a value (dV / dD) obtained by differentiating the pore volume (V) with respect to the pore diameter (D) is plotted against the pore diameter (D). ) At the maximum peak. The pore size distribution curve can be obtained by the method described below. That is, silica-based mesoporous particles are cooled to a liquid nitrogen temperature (-196 ° C.), nitrogen gas is introduced, the adsorption amount is determined by a constant volume method or a gravimetric method, and then the pressure of the introduced nitrogen gas is gradually increased. And the adsorption amount of nitrogen gas for each equilibrium pressure is plotted to obtain an adsorption isotherm. Using this adsorption isotherm, a pore size distribution curve can be obtained by a calculation method such as Cranston-Inklay method, Dollimore-Heal method, BJH method or the like.

In the spherical silica-based mesoporous material of the present invention, it is preferable that 60% or more of the total pore volume is included in the range of ± 40% of the center pore diameter in the pore size distribution curve. The silica-based mesoporous particle satisfying this condition means that the pore diameter is very uniform. The specific surface area of such a spherical silica-based mesoporous material is not particularly limited, but is preferably 700 m ² / g or more. The specific surface area can be calculated as a BET specific surface area from the adsorption isotherm using the BET isotherm adsorption equation.

Further, such a spherical silica-based mesoporous material preferably has one or more peaks at a diffraction angle corresponding to a d ₁₀₀ value of 1 nm or more in the X-ray diffraction pattern. The X-ray diffraction peak means that a periodic structure having a d ₁₀₀ value corresponding to the peak angle is present in the sample. Therefore, the presence of one or more peaks at a diffraction angle corresponding to a d ₁₀₀ value of 1 nm or more means that the pores are regularly arranged at intervals of 1 nm or more.

  Further, the radial pores possessed by the spherical silica-based mesoporous material according to the present invention are pores having a so-called radial type structure in which the pores are arranged radially from the center to the outside. As described above, since the pores are arranged from the center of the particle toward the outside while maintaining regularity, the outer surface is reduced and a structure suitable as a catalyst or an adsorbent is obtained. In addition, it is confirmed that spherical silica-based mesoporous materials have a so-called radial structure by introducing a metal such as gold or platinum into the pores and observing the cross section with a scanning electron microscope. Is possible. Further, it is not necessary that all the pores in the spherical silica-based mesoporous material of the present invention are arranged radially from the center to the outside, and 50% or more (more preferably 70% or more) of all the pores. ) Are preferably arranged in this way.

  Furthermore, the pore arrangement state (pore arrangement structure or structure) in the spherical silica-based mesoporous material of the present invention is not particularly limited, but is preferably a 2d-hexagonal structure, a 3d-hexagonal structure, or a cubic structure. Such a pore arrangement structure may have a disordered pore arrangement structure.

  Here, that the porous body has a hexagonal pore arrangement structure means that the arrangement of the pores is a hexagonal structure (S. Inagaki, et al., J. Chem. Soc., Chem. Commun. 680, 1993; S. Inagaki, et al., Bull. Chem. Soc. Jpn., 69, 1449, 1996, Q. Huo, et al., Science, 268, 1324, 1995). Further, the porous body having a cubic pore arrangement structure means that the arrangement of pores is a cubic structure (JCVartuli, et al., Chem. Mater., 6, 2317, 1994; Q. Huo, et al., Nature, 368, 317, 1994). Further, the porous body having a disordered pore arrangement structure means that the arrangement of the pores is irregular (PTTanev, et al., Science, 267,865, 1995; SABagshaw, et al. Science, 269, 1242, 1995; R. Ryoo, et al., J. Phys. Chem., 100, 17718, 1996). The cubic structure is preferably Pm-3n, Im-3m or Fm-3m symmetric. The symmetry is determined based on a space group notation.

  In the spherical silica-based mesoporous material as described above, the method for introducing the 3-aminopropyl group is organic alkoxy during the synthesis of the spherical mesoporous silica as in the first method for producing the spherical silica-based mesoporous material of the present invention described later. Even in the copolymerization method in which silane is added, a 3-aminopropyl group is added to the spherical silica mesoporous material composed of inorganic components as in the second method for producing the spherical silica mesoporous material of the present invention described later. It may be a grafting method in which the above is modified. Among these methods, in the case of the graft method, the copolymerization method is preferable from the viewpoint that pores are blocked or that the amount of 3-aminopropyl group introduced is difficult to control.

  Such a spherical silica-based mesoporous material may be used as it is, but may be molded and used as necessary. Any molding means may be used, but extrusion molding, tablet molding, rolling granulation, compression molding, CIP and the like are preferable. The shape can be determined according to the place of use and method, and examples thereof include a columnar shape, a crushed shape, a spherical shape, a honeycomb shape, an uneven shape, and a corrugated plate shape. In addition, such a spherical silica-based mesoporous material is useful as a base catalyst for a reaction product having a particularly high molecular weight.

<Method for producing spherical silica-based mesoporous material>
Next, the manufacturing method of the spherical silica type mesoporous material of this invention is demonstrated.

(First manufacturing method)
First, the 1st manufacturing method (copolymerization method) of the spherical silica type mesoporous material of this invention is demonstrated. In the first method for producing a spherical silica-based mesoporous material of the present invention, first, a porous material in which a silica raw material and a surfactant are mixed in a solvent, and the surfactant is introduced into the silica raw material. Precursor particles are obtained (first step).

  At least a part of the silica raw material used in the first production method of the present invention needs to be an organoalkoxysilane containing a 3-aminopropyl group.

  As such an organic alkoxysilane containing a 3-aminopropyl group, a trialkoxysilane having three alkoxy groups, a dialkoxysilane having two alkoxy groups, and a monoalkoxysilane having one alkoxy group can be used. . The type of alkoxy group is not particularly limited, but those having a relatively small number of carbon atoms in the alkoxy group such as methoxy group, ethoxy group, propoxy group, and butoxy group are advantageous from the viewpoint of reactivity. As such an organic alkoxysilane containing a 3-aminopropyl group, various conventionally known compounds containing a 3-aminopropyl group can be used and are not particularly limited. For example, it is a trialkoxysilane. And 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, and the like. These organoalkoxysilanes containing a 3-aminopropyl group can be used alone or in combination of two or more.

  Moreover, as a silica raw material used in the present invention, other alkoxysilanes are used in addition to the organic alkoxysilanes containing the 3-aminopropyl group. As such other alkoxysilanes, tetraalkoxysilane having 4 alkoxy groups, trialkoxysilane having 3 alkoxy groups, and dialkoxysilane having 2 alkoxy groups can be used. The type of alkoxy group is not particularly limited, but those having a relatively small number of carbon atoms in the alkoxy group (such as those having about 1 to 4 carbon atoms) such as methoxy group, ethoxy group, propoxy group, butoxy group, etc. This is advantageous in terms of reactivity. In addition, when the alkoxysilane has 3 or 2 alkoxy groups, an organic group, a hydroxyl group, or the like may be bonded to the silicon atom in the alkoxysilane.

  Examples of such tetraalkoxysilane include tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, tetrabutoxysilane, and dimethoxydiethoxysilane. Examples of such trialkoxysilane include trimethoxysilanol and triethoxysilane. Examples include silanol, trimethoxymethylsilane, trimethoxyvinylsilane, triethoxyvinylsilane, and the like. Examples of such dialkoxysilane include dimethoxydimethylsilane and diethoxydimethylsilane.

  These alkoxysilanes can be used alone or in combination of two or more. Moreover, the alkoxysilane having 2 to 4 alkoxy groups described above can be used in combination with a monoalkoxysilane having one alkoxy group. Examples of the monoalkoxysilane that can be used in this way include trimethylmethoxysilane, trimethylethoxysilane, and 3-chloropropyldimethylmethoxysilane.

  Alkoxysilane produces a silanol group by hydrolysis, and the resulting silanol groups condense to form a 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, tetraalkoxysilane having a large number of alkoxy groups is preferably used as alkoxysilane, and tetramethoxysilane or tetraethoxysilane is particularly preferably used as tetraalkoxysilane from the viewpoint of reaction rate.

  In addition, it is preferable that the ratio of the organic alkoxysilane containing the said 3-aminopropyl group is a ratio of 0.1-20 mol% with respect to the whole quantity of a silica raw material. When the ratio of the organoalkoxysilane is less than 0.1 mol%, the catalyst performance tends to decrease. On the other hand, if the amount exceeds 20 mol%, the 3-aminopropyl group has a positive charge. Therefore, when an ammonium salt is used as the surfactant, charge repulsion occurs and it becomes difficult to form spherical particles. It tends to be difficult to form spherical particles and regular mesoporous structures.

  The surfactant used in the present invention is an alkyl ammonium halide represented by the following general formula (1).

And R < ¹ >, R < ² >, R < ³ > in General formula (1) may be same or different, and respectively shows a C1-C3 alkyl group. Examples of such an alkyl group include a methyl group, an ethyl group, and a propyl group, and these may be mixed in one molecule, but R ¹ , R ² , R ^{3 are used} from the viewpoint of symmetry of the surfactant molecule. Are preferably the same. When the symmetry of the surfactant molecule is excellent, aggregation of the surfactants (formation of micelles, etc.) tends to be facilitated. ^Furthermore, R ^1, it is preferable that at least one of R 2, ^{R 3} is a methyl ^group, and more preferably all of R ^1, R 2, ^{R 3} is a methyl group.

  Moreover, n in General formula (1) shows the integer of 9-25, and it is more preferable that it is an integer of 9-17. With alkylammonium halides where n is 8 or less, a spherical porous body cannot be obtained. Moreover, the center pore diameter becomes smaller than 1.0 nm, and the catalytic reactivity in the pores is lowered. On the other hand, in the case of the alkylammonium halide having n of 26 or more, the hydrophobic interaction of the surfactant is too strong, so that a layered compound is generated and a spherical porous body cannot be obtained.

  Furthermore, X in the general formula (1) represents a halogen atom, and the kind of such a halogen atom is not particularly limited, but X is preferably a chlorine atom or a bromine atom from the viewpoint of easy availability.

Therefore, as the surfactant represented by the general formula (1), all of R ¹ , R ² and R ³ are methyl groups and alkyltrimethylammonium halides having a long-chain alkyl group having 10 to 26 carbon atoms. Among them, decyltrimethylammonium halide, dodecyltrimethylammonium halide, tetradecyltrimethylammonium halide, hexadecyltrimethylammonium halide, octadecyltrimethylammonium halide, eicosyltrimethylammonium halide, and docosyltrimethylammonium halide are more preferable.

  Such a surfactant forms a complex in a solvent together with the silica raw material. The silica raw material in the composite is changed to silicon oxide by the reaction, but silicon oxide is not generated in the part where the surfactant is present, so pores are formed in the part where the surfactant is present. Will be. That is, the surfactant is introduced into the silica raw material and functions as a template for pore formation. In the present invention, the surfactant can be used alone or in combination of two or more, but as described above, the surfactant acts as a template for forming pores in the reaction product of the silica raw material, Since the type greatly affects the pore shape 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, an aqueous solvent containing alcohol is used as a solvent for mixing the silica raw material and the surfactant. Examples of such alcohol include methanol, ethanol, isopropanol, n-propanol, ethylene glycol, and glycerin, and methanol or ethanol is preferable from the viewpoint of solubility of the silica raw material.

  In the present invention, when synthesizing the porous precursor particles in which the surfactant is introduced into the silica raw material, it is important to use an aqueous solvent having an alcohol content of 80% by volume or less. More preferably, the alcohol content is 10 to 70% by volume. When the alcohol content exceeds 80% by volume, it is difficult to control the particle size and particle size distribution, and the resulting spherical silica-based mesoporous material is less uniform in particle size. By using an aqueous solvent containing a relatively large amount of alcohol, generation and growth of uniform spheres are realized, and the particle diameter of the obtained spherical silica mesoporous material is highly uniformly controlled. It becomes.

  Further, in the present invention, by changing the ratio of water and alcohol, the particle size of the obtained spherical silica-based mesoporous material is easily controlled while maintaining the uniformity of the particle size at a high level. be able to. That is, when the water ratio is high, the porous body is likely to precipitate, so the particle size is small. Conversely, when the alcohol ratio is high, a porous body having a large particle size can be obtained.

  Further, in the present invention, when the porous material precursor particles are obtained by mixing the silica raw material and the surfactant in the aqueous solvent, the concentration of the surfactant described above is 0 based on the total volume of the solution. 0.003 to 0.03 mol / L (preferably 0.0005 to 0.02 mol / L), and the concentration of the silica raw material described above is 0.0005 to 0.03 mol / L (preferably based on the total volume of the solution) , 0.003 to 0.015 mol / L). By strictly controlling the concentrations of the surfactant and the silica raw material in this way, the generation and growth of uniform spherical bodies are realized in combination with the use of the aqueous solvent described above, and the resulting spherical silica meso The particle size of the porous body is highly uniformly controlled. When the concentration of the surfactant is less than 0.0003 mol / L, a sufficient porous body cannot be obtained because the amount of the surfactant to be a template is insufficient, and the particle size and particle size distribution are controlled. The particle size uniformity of the spherical silica-based mesoporous material obtained becomes difficult. On the other hand, when the concentration of the surfactant exceeds 0.03 mol / L, a porous body having a spherical shape cannot be obtained at a high ratio, and control of the particle size and particle size distribution becomes difficult. The uniformity of the particle size of the resulting spherical silica-based mesoporous material is reduced. In addition, when the concentration of the silica raw material is less than 0.0005 mol / L, a porous body having a spherical shape cannot be obtained at a high ratio, and it becomes difficult to control the particle size and particle size distribution. The uniformity of the particle size of the spherical silica-based mesoporous material is lowered. On the other hand, when the concentration of the silica raw material exceeds 0.03 mol / L, a good porous body cannot be obtained because the ratio of the surfactant to be a template is insufficient, and the particle size and particle size distribution are further reduced. The uniformity of the particle size of the spherical silica-based mesoporous material obtained because of difficulty in control becomes low.

  Moreover, in this invention, when mixing the said silica raw material and the said surfactant, it is preferable to mix on basic conditions. The silica raw material generally reacts under basic and acidic conditions and changes to silicon oxide, but the concentration of the silica raw material and the surfactant in the present invention is considerably lower than that of the prior art method. Therefore, the reaction hardly proceeds under acidic conditions. Therefore, in the present invention, it is preferable to react the silica raw material under basic conditions. In addition, when the silica raw material is reacted under basic conditions, the reaction point of silicon atoms is increased when the reaction is performed under basic conditions, and a silicon oxide having excellent physical properties such as moisture resistance and heat resistance is obtained. In this respect, mixing under basic conditions is also advantageous.

  In order to make the aqueous solvent basic, a basic substance such as a sodium hydroxide aqueous solution is usually added. There are no particular restrictions on the basic conditions during the reaction, 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 should be 0.1 to 0.9. Preferably, it 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 raw material is less than 0.1, the yield tends to decrease, and on the other hand, it exceeds 0.9. In such a case, the formation of the porous body tends to be difficult.

  The reaction conditions (reaction temperature, reaction time, etc.) in the first step as described above are not particularly limited, and the reaction temperature is, for example, -20 ° C to 100 ° C (preferably 0 ° C to 80 ° C, more preferably 10 ° C. to 40 ° C.). Further, the reaction is preferably allowed to proceed with stirring.

  In addition, as a specific example of such a 1st process, the following methods are mentioned, for example. That is, first, a surfactant and a basic substance are added to an aqueous solvent containing alcohol to prepare a basic solution of the surfactant, and a silica raw material is added to this solution. Since the added silica raw material is hydrolyzed (or hydrolyzed and condensed) in the solution, a white powder is deposited several seconds to several tens of minutes after the addition. In this case, the reaction temperature is preferably 0 ° C to 80 ° C, more preferably 10 ° C to 40 ° C. 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 the completion of stirring, the porous precursor particles according to the present invention can be obtained by allowing the system to stand overnight at room temperature as necessary, stabilizing the system, and filtering and washing the resulting precipitate as necessary.

  Next, in the first method for producing the spherical silica mesoporous material of the present invention, the surfactant contained in the porous precursor particles obtained in the first step is removed to remove the spherical silica mesoporous material. A body is obtained (second step). Examples of the method for removing the surfactant in this way include a method of treating with an organic solvent and an ion exchange method.

  In the case of treating with an organic solvent, the surfactant is extracted by immersing the porous precursor particles in a good solvent having high solubility in the used surfactant. In the ion exchange method, the porous precursor particles are immersed in an acidic solution (such as ethanol containing a small amount of hydrochloric acid) and stirred, for example, while heating at 50 to 70 ° C. Thereby, the surfactant existing in the pores of the porous precursor particles is ion-exchanged with hydrogen ions. In addition, although hydrogen ions remain in the hole by ion exchange, the problem of blockage of the hole does not occur because the ion radius of the hydrogen ion is sufficiently small.

(Second manufacturing method)
Next, the 2nd manufacturing method (graft method) of the spherical silica type mesoporous material of this invention is demonstrated. In the second method for producing a spherical silica-based mesoporous material of the present invention, first, a spherical silica-based mesoporous material is used in the same manner as in the first manufacturing method described above except that the other alkoxysilane is used as a silica raw material. (First step, second step).

  In the second method for producing the spherical silica-based mesoporous material of the present invention, as a method for removing the surfactant, a method using baking is used in addition to the method for treating with an organic solvent and the ion exchange method described above. Can do. In such a firing method, the porous precursor particles are heated at 300 to 1000 ° C., preferably 400 to 700 ° C. The heating time may be about 30 minutes, but it is preferable to heat for 1 hour or longer in order to completely remove the surfactant. The firing can be performed in the air, but since a large amount of combustion gas is generated, it may be performed by introducing an inert gas such as nitrogen.

  Then, the spherical silica-based mesoporous material is graft-polymerized with an organic alkoxysilane containing a 3-aminopropyl group (third step). Examples of the method for graft polymerization in this manner include a method in which spherical mesoporous silica, an organic alkoxysilane containing a 3-aminopropyl group, and an organic solvent are mixed and then heated. It is preferable that the usage-amount of such an organic alkoxysilane containing 3-aminopropyl group is 0.01-10 equivalent with respect to the surface silanol group of the said spherical mesoporous silica. If the amount of the organoalkoxysilane used is less than the lower limit, the catalytic activity tends to decrease because the 3-aminopropyl group is insufficient. On the other hand, when the upper limit is exceeded, an excessive amount of organoalkoxysilane is bonded and the pores tend to be blocked. Moreover, it is preferable that the usage-amount of such an organic solvent is 1-1000 weight part with respect to 1 weight part of the said spherical mesoporous silica. Furthermore, as heating conditions, the heating temperature is preferably 40 to 150 ° C., and the heating time is preferably 0.5 to 48 hours.

  According to the production method of the present invention as described above, a spherical silica-based mesoporous material having an average particle diameter of 0.01 to 3 μm and having a relatively large central pore diameter of 1 to 5 nm. A system mesoporous material can be obtained efficiently and reliably.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example. In Examples and Comparative Examples, those having the following structural formulas were used as silica raw materials for introducing organic functional groups.

Example 1
First, 3.52 g of hexadecyltrimethylammonium chloride (surfactant) was dissolved in 800 g of a water / methanol solution (weight ratio 1/1) and stirred while maintaining the temperature at 25 ° C. in a constant temperature water bath. Next, 2.28 mL of 1 mol / L sodium hydroxide solution was added to the obtained mixed solution. Thereafter, a tetramethoxysilane (TMOS) / 3-aminopropyltrimethoxysilane (APTMS) mixture (molar ratio 9/1) 8.68 × 10 ⁻³ mol previously mixed in a dry nitrogen stream as a silica raw material was added. After adding the silica raw material, precipitation of particles was observed within a few minutes, and the solution became cloudy. Thereafter, the resulting cloudy solution was stirred for about 8 hours and allowed to stand overnight (14 hours) to obtain a product. Then, the operation of filtering the obtained product and redispersing in water was repeated twice, followed by drying at 45 ° C. overnight (14 hours) to obtain a silica / surfactant complex. Next, 0.5 g of the obtained complex was dispersed in 50 mL of ethanol, 0.5 mL of hydrochloric acid was added, and the mixture was stirred in an oil bath at a temperature of 60 ° C. for 3 hours to extract the surfactant. Then, after fully washing | cleaning with ethanol, it dried at 45 degreeC for 24 hours, and obtained the spherical silica type mesoporous material.

An X-ray diffraction pattern of the obtained spherical silica-based mesoporous material is shown in FIG. X-ray diffraction pattern shown in Figure 1, obtained spherical mesoporous silica material has a peak of d ₁₀₀ value 41.1 angstroms (Å), yet correspond to hexagonal arrangement of pores It was confirmed that it had peaks of (100), (110) and (200). Therefore, it was confirmed that the obtained spherical silica-based mesoporous material has high pore regularity.

  Next, the obtained spherical silica-based mesoporous material was observed with a scanning electron microscope (SEM). The obtained SEM photograph is shown in FIG. When the diameter of 50 arbitrary particles was measured in the SEM photograph, the particle size distribution of 50 arbitrary particles was 0.54 to 0.69 μm, and the average particle size was 0.62 μm. The proportion of particles having a particle size in the range of ± 10% of the average particle size was 95% by weight of the total particles, and the obtained spherical silica mesoporous material was in a monodispersed state.

  Further, gold was partially introduced into the pores of the obtained spherical silica-based mesoporous material, and then observed with a transmission electron microscope (TEM). The obtained TEM photograph is shown in FIG. From the TEM photograph shown in FIG. 3, it was confirmed that in the obtained spherical silica-based mesoporous material, hexagonal pores were directed outward from the center of the sphere, and radial pores were formed.

(Example 2)
Implemented except that a tetramethoxysilane (TMOS) / 3-aminopropyltrimethoxysilane (APTMS) mixture (molar ratio 4/1) 8.68 × 10 ⁻³ mol previously mixed in a dry nitrogen stream as a silica raw material was used. In the same manner as in Example 1, a spherical silica-based mesoporous material was obtained.

Obtained spherical mesoporous silica material has a peak of d ₁₀₀ value 36.9 angstroms (Å), it was confirmed that a high regularity of the pores. Moreover, the particle size distribution of 50 arbitrary particles of the obtained spherical silica-based mesoporous material was 0.42 to 0.63 μm, and the average particle size was 0.55 μm. Furthermore, the proportion of particles having a particle size within a range of ± 10% of the average particle size was 92% by weight of the total particles, and the obtained spherical silica-based mesoporous material was in a monodispersed state. In addition, it was confirmed that radial pores were formed in the obtained spherical silica-based mesoporous material.

(Example 3)
Implemented except that a tetramethoxysilane (TMOS) / 3-aminopropyltrimethoxysilane (APTMS) mixture (molar ratio 19/1) 8.68 × 10 ⁻³ mol previously mixed in a dry nitrogen stream as a silica raw material was used. In the same manner as in Example 1, a spherical silica-based mesoporous material was obtained.

Obtained spherical mesoporous silica material has a peak of d ₁₀₀ value 35.6 angstroms (Å), it was confirmed that a high regularity of the pores. The particle size distribution of 50 arbitrary particles of the obtained spherical silica-based mesoporous material was 0.50 to 0.67 μm, and the average particle size was 0.60 μm. Further, the proportion of particles having a particle size within the range of ± 10% of the average particle size was 95% by weight of the total particles, and the obtained spherical silica-based mesoporous material was in a monodispersed state. In addition, it was confirmed that radial pores were formed in the obtained spherical silica-based mesoporous material.

Example 4
Implemented except that a tetraethoxysilane (TEOS) / 3-aminopropyltrimethoxysilane (APTMS) mixture (molar ratio 9/1) 8.68 × 10 ⁻³ mol previously mixed in a dry nitrogen stream as a silica raw material was used. In the same manner as in Example 1, a spherical silica-based mesoporous material was obtained.

Obtained spherical mesoporous silica material has a peak of d ₁₀₀ value 39.0 angstroms (Å), it was confirmed that a high regularity of the pores. In addition, the particle size distribution of 50 arbitrary particles of the obtained spherical silica-based mesoporous material was 0.82 to 1.15 μm, and the average particle size was 0.95 μm. Further, the proportion of particles having a particle size within the range of ± 10% of the average particle size was 95% by weight of the total particles, and the obtained spherical silica-based mesoporous material was in a monodispersed state. In addition, it was confirmed that radial pores were formed in the obtained spherical silica-based mesoporous material.

(Example 5)
A spherical silica mesoporous material was obtained in the same manner as in Example 1 except that 3.36 g of octadecyltrimethylammonium chloride was used as the surfactant.

Obtained spherical mesoporous silica material has a peak of d ₁₀₀ value 38.2 angstroms (Å), it was confirmed that a high regularity of the pores. The particle size distribution of 50 arbitrary particles of the obtained spherical silica-based mesoporous material was 0.66 to 0.88 μm, and the average particle size was 0.74 μm. Further, the proportion of particles having a particle size within a range of ± 10% of the average particle size was 96% by weight of the total particles, and the obtained spherical silica-based mesoporous material was in a monodispersed state. In addition, it was confirmed that radial pores were formed in the obtained spherical silica-based mesoporous material.

(Example 6)
Spherical silica was used in the same manner as in Example 3 except that 1.54 g of decyltrimethylammonium bromide was used as the surfactant, the water / methanol solution weight ratio was 3/1, and the reaction temperature in the constant temperature bath was 30 ° C. A system mesoporous material was obtained.

Obtained spherical mesoporous silica material has a peak of d ₁₀₀ value 29.1 angstroms (Å), it was confirmed that a high regularity of the pores. Further, the particle size distribution of 50 arbitrary particles of the obtained spherical silica-based mesoporous material was 0.40 to 0.58 μm, and the average particle size was 0.49 μm. Further, the proportion of particles having a particle size within the range of ± 10% of the average particle size was 94% by weight of the total particles, and the obtained spherical silica-based mesoporous material was in a monodispersed state. In addition, it was confirmed that radial pores were formed in the obtained spherical silica-based mesoporous material.

(Example 7)
First, synthetic silica was obtained in the same manner as in Example 1 except that tetramethoxysilane (TMOS) 8.68 × 10 ⁻³ mol was used as a silica raw material. Next, 0.8 g of the obtained synthetic silica, 80 g of dehydrated toluene, and 2.15 g of 3-aminopropyltrimethoxysilane (APTMS) were mixed and refluxed at 90 ° C. for 15 hours. The obtained product was filtered and dried at 45 ° C. overnight (14 hours) to obtain a spherical silica-based mesoporous material.

Obtained spherical mesoporous silica material has a peak of d ₁₀₀ value 32.6 angstroms (Å), it was confirmed that a high regularity of the pores. Further, the particle size distribution of 50 arbitrary particles of the obtained spherical silica-based mesoporous material was 0.44 to 0.56 μm, and the average particle size was 0.51 μm. Further, the proportion of particles having a particle size within a range of ± 10% of the average particle size was 99% by weight of the total particles, and the obtained spherical silica-based mesoporous material was in a monodispersed state. In addition, it was confirmed that radial pores were formed in the obtained spherical silica-based mesoporous material.

(Comparative Example 1)
Tetraethoxysilane (TEOS) / N- (2-aminoethyl) -3-aminopropyltrimethoxysilane (AAPTMS) mixture (molar ratio 9/1) 8.68 × 10 8 previously mixed in a dry nitrogen stream as a silica raw material ^A comparative spherical silica-based mesoporous material was obtained in the same manner as in Example 1 except that ^-3 mol was used.

Obtained spherical mesoporous silica material has a peak of d ₁₀₀ value 36.3 angstroms (Å), it was confirmed that a high regularity of the pores. The obtained spherical silica-based mesoporous material had a spherical particle shape and an average particle diameter of 0.51 μm. However, the particle size distribution of 50 arbitrary particles is 0.39 to 0.62 μm, and the proportion of particles having a particle size in the range of ± 10% of the average particle size is 85% by weight of the total particles. The obtained spherical silica-based mesoporous particles were not in a monodispersed state.

(Comparative Example 2)
A silica-based mesoporous material for comparison was obtained in the same manner as in Example 3 except that a mixed solution of 0.35 g of hexadecyltrimethylammonium chloride, 5 g of water, and 5 g of methanol was used.

The obtained mesoporous silica material has a peak of d ₁₀₀ value 35.5 angstroms (Å), it was confirmed that a high regularity of the pores. The particle shape of the silica-based mesoporous material was rod-shaped.

(Comparative Example 3)
5.49 mmol of hexadecyltrimethylammonium chloride, 14 mmol of 2M aqueous sodium hydroxide solution and 480 g of water were mixed and stirred at 80 ° C. for 30 minutes. After confirming that the solution had a pH of 12.3, 44.8 mmol of tetraethoxysilane (TEOS) and 3- [2- (2-aminoethylamino) ethylamino] propyltrimethoxy were added to the obtained mixed solution. Silane (AEPTMS) 5.75 mmol was sequentially added, and the mixture was stirred at 80 ° C. for 2 hours. The obtained product was filtered and vacuum-dried to obtain a silica / surfactant complex. 1 g of the obtained complex was dispersed in 100 mL of methanol, 1 g of hydrochloric acid was added, and the mixture was stirred in an oil bath at a temperature of 60 ° C. for 3 hours to extract the surfactant. Thereafter, the obtained porous silica was filtered and dried under vacuum to obtain a comparative spherical silica mesoporous material.

The resulting spherical silica-based mesoporous material had a peak of d ₁₀₀ value 38.4 angstroms (Å), the direction of the pores by TEM observation was estimated to be irregular. The obtained spherical silica-based mesoporous material had a spherical particle shape and an average particle size of 1.4 μm. However, the particle size distribution of 50 arbitrary particles is 0.6 to 2.1 μm, and the proportion of particles having a particle size in the range of ± 10% of the average particle size is 50% by weight of the total particles. The obtained spherical silica-based mesoporous particles were not in a monodispersed state.

(Comparative Example 4)
1 g of spherical silica having no mesoporous structure (spherical fine powder Seahorster, Nippon Shokubai Co., Ltd., particle size 500 nm), 0.2 g of 3-aminopropyltrimethoxysilane (APTMS) and 20 mL of dehydrated toluene were mixed at 90 ° C. Refluxed for 15 hours. The obtained product was filtered and dried at 45 ° C. overnight (14 hours) to obtain a comparative spherical silica.

  In the obtained spherical silica, pores could not be confirmed. Moreover, the particle shape of the obtained spherical silica was spherical, the particle size distribution of 50 arbitrary particles was 0.47 to 0.61 μm, and the average particle size was 0.55 μm. Furthermore, the proportion of particles having a particle size within a range of ± 10% of the average particle size was 98% by weight of the total particles, and the obtained spherical silica was in a monodispersed state.

(Comparative Example 5)
FSM-16 (synthesized according to literature (J. Chem. Soc., Chem. Commun., 680, 1993)) 0.8 g, 2.67 g of 3-aminopropyltrimethoxysilane (APTMS) and 80 mL of dehydrated toluene were mixed. And refluxed at 90 ° C. for 15 hours. The obtained product was filtered and dried at 45 ° C. overnight (14 hours) to obtain a silica-based mesoporous material for comparison.

The obtained mesoporous silica material is 37.4 angstroms (Å) has a peak of d ₁₀₀ value, it pores are not radially was confirmed. Further, the particle shape of the obtained silica-based mesoporous material was indefinite.

(Comparative Example 6)
3 g of MCM-41 (synthesized according to the literature (J. Org. Chem. 62, 749, 1997)), 3 g of 3-aminopropyltrimethoxysilane (APTMS) and 50 mL of dehydrated toluene were mixed and refluxed at 90 ° C. for 1.5 hours. . And after distilling off toluene, it heated. The obtained product was filtered and dried at 120 ° C. overnight (14 hours) to obtain a silica-based mesoporous material for comparison.

The obtained mesoporous silica material has had a peak of d ₁₀₀ value 37.9 angstroms (Å), that the pores are not radially was confirmed. Further, the particle shape of the obtained silica-based mesoporous material was indefinite.

(Comparative Example 7)
A comparative spherical silica-based mesoporous material was obtained in the same manner as in Example 1 except that 8.68 × 10 ⁻³ mol of tetramethoxysilane (TMOS) was used as a silica raw material.

Obtained spherical mesoporous silica material has a peak of d ₁₀₀ value 33.1 angstroms (Å), it was confirmed that a high regularity of the pores. Moreover, the particle shape of the obtained spherical silica-based mesoporous material was spherical, the particle size distribution of 50 arbitrary particles was 0.47 to 0.59 μm, and the average particle size was 0.54 μm. Further, the proportion of particles having a particle size within a range of ± 10% of the average particle size was 98% by weight of the total particles, and the obtained spherical silica-based mesoporous material was in a monodispersed state.

<Physical properties of the composite>
The physical properties of the spherical silica-based mesoporous materials obtained in Examples 1 to 6 are as shown in Table 1. The physical properties of the silica-based mesoporous materials obtained in Comparative Examples 1 to 7 (spherical silica in Comparative Example 4) were as shown in Table 2. In addition, the organic functional group introduction amount, specific surface area, central pore diameter, and pore volume of the synthesized product were evaluated by the following methods.

(I) Amount of introduction of organic functional group First, thermogravimetric analysis of the sample was carried out at a rate of temperature increase of 10 ° C./min in a N ₂ stream using a thermal analyzer (manufactured by Rigaku Corporation, THERMO PLUS TG8120). The weight loss rate when heated to 500 ° C. was measured. Next, the thermogravimetric analysis similar to the above was performed on the synthetic silica obtained in Comparative Example 7, and the weight loss rate when heated from 150 ° C. to 500 ° C. was measured. And the amount of organic functional group introduction was computed from the difference of these weight decreasing rates.

(Ii) Pore volume, specific surface area and central pore diameter First, the sample was vacuum degassed at 100 ° C. for 2 hours. Next, the N ₂ adsorption isotherm of the sample subjected to the vacuum degassing treatment was measured by a constant volume method under the condition of liquid N ₂ temperature (77 K) using Belsorb-mini manufactured by Nippon Bell. The pore volume was calculated from the obtained N ₂ adsorption isotherm, and the specific surface area was calculated using the BET isotherm equation. Further, the central pore diameter was calculated from the obtained N ₂ adsorption isotherm by the BJH method.

<Base catalyst performance evaluation>
Using the silica-based mesoporous material obtained in Examples 1-6 and Comparative Examples 1-7 (spherical silica in Comparative Example 4) as a base catalyst, the yield and turnover number of the product in the nitroaldol reaction are measured. Thus, the base catalyst performance of the obtained synthesized product was evaluated. That is, first, 50 mg of a base catalyst was added to 0.61 g (5 mmol) of p-hydroxybenzaldehyde and 10 ml of nitromethane, and reacted at 90 ° C. for 1 hour. Next, the base catalyst was removed from the resulting reaction mixture by filtration, the base catalyst was washed with chloroform, and then the filtrate was concentrated under reduced pressure. Next, acetone-d ₆ was added to the obtained residue to completely dissolve it, THF was added to the internal standard, ¹ H-NMR measurement of this solution was performed, and the product amount was determined from the integral value of the proton of the vinyl group. Went. Then, the turnover number was calculated by dividing the product amount (mmol) by the active site of the catalyst (introduction amount of organic functional group (mmol)) (Reaction 1). Further, the amount of product was determined and the turnover number was calculated in the same manner as in the above method except that 1.17 g (5 mmol) of 4-n-octyloxybenzaldehyde was used as a reactant (Reaction 2). In the case where the silica-based mesoporous material obtained in Comparative Example 3 was used as the base catalyst, the reaction time was 20 hours. In addition, when the silica-based mesoporous material obtained in Comparative Example 6 was used as a base catalyst, the amount of the reaction product was 2.5 mmol. The obtained results are shown in Table 3.

  As is clear from the results shown in Table 3, when the spherical silica-based mesoporous material of the present invention was used as a base catalyst (Examples 1 to 6), the product yield and turnover number were high. In addition, the spherical silica-based mesoporous material of the present invention (Examples 1 to 5) synthesized by the copolymerization method exhibits high catalytic performance, and although reaction 2 is a bulky molecular reaction compared to reaction 1, It was revealed that the catalyst was an excellent catalyst with almost no change in the over number.

  On the other hand, although the spherical silica-based mesoporous material obtained in Comparative Example 1 into which N- (2-aminoethyl) -3-aminopropyl group was introduced exhibits a certain degree of catalytic performance, the functional group may be bulky. Compared with the spherical silica-based mesoporous material of the present invention, the turnover number was also low. In addition, since the pores are small, the catalyst performance was significantly lowered in Reaction 2, which is a bulky molecular reaction. Further, the silica-based mesoporous material obtained in Comparative Example 2 in which the particle shape is rod-shaped is more turned than the spherical silica-based mesoporous material obtained in Example 3 in which the introduction amount of 3-aminopropyl group is equal. The over number was low. Further, the spherical silica-based mesoporous material obtained in Comparative Example 3 in which the size of the spherical particles is non-uniform and the direction of the pores is not uniform is low in turn even though the reaction time is 20 hours. The number was over. In addition, the spherical silica obtained in Comparative Example 4 that is spherical but has no pores exhibits a certain degree of catalytic performance, but has a lower catalytic performance than the spherical silica-based mesoporous material of the present invention, and the catalytic reaction is fine. It was suggested that it occurred efficiently in the hole.

  Further, the other 3-aminopropyl groups which are typical mesoporous silicas such as FSM and MCM grafted with 3-aminopropyl groups (Comparative Examples 5 and 6) also show some catalytic performance, but the same 3-aminopropyl groups. The turnover number was lower than that of the spherical silica-based mesoporous material of the present invention obtained in Example 6 grafted with No. 1.

  Therefore, it was confirmed that the spherical silica-based mesoporous material of the present invention has excellent base catalyst performance.

  As described above, according to the present invention, it is possible to provide a spherical silica mesoporous material having excellent base catalyst performance. Therefore, the spherical silica mesoporous material of the present invention is useful as a base catalyst, an adsorbing material and the like.

2 is a graph showing an X-ray diffraction pattern of the spherical silica-based mesoporous material obtained in Example 1. 2 is a SEM photograph of a spherical silica-based mesoporous material obtained in Example 1. 2 is a TEM photograph of gold introduced into a part of pores of a spherical silica-based mesoporous material obtained in Example 1. FIG.

Claims (6)

  A spherical silica-based mesoporous material having an average particle diameter of 0.01 to 3 μm and radial pores having a central pore diameter of 1 to 5 nm, wherein the spherical silica-based mesoporous material is 3-aminopropyl A spherical silica-based mesoporous material, which is modified with a group.   The spherical silica-based mesoporous material according to claim 1, wherein the 3-aminopropyl group is coordinated to an Si atom in a silicate skeleton constituting the spherical silica-based mesoporous material.   3. The spherical shape according to claim 1, wherein 90% by weight or more of all the particles of the spherical silica-based mesoporous material have a particle size within a range of ± 10% of the average particle size. Silica-based mesoporous material. A first step of mixing a silica raw material and a surfactant in a solvent to obtain porous precursor particles obtained by introducing the surfactant into the silica raw material;
A second step of obtaining a spherical silica-based mesoporous material by removing the surfactant contained in the porous material precursor particles;
A method for producing a spherical silica-based mesoporous material comprising:
At least a part of the silica raw material is an organic alkoxysilane containing a 3-aminopropyl group, and the surfactant is represented by the following general formula (1):
[Wherein R ¹ , R ² and R ³ may be the same or different and each represents an alkyl group having 1 to 3 carbon atoms, X represents a halogen atom, and n represents an integer of 9 to 25, respectively. ]
Is used, an aqueous solvent having an alcohol content of 80% by volume or less is used as the solvent, and the concentration of the surfactant in the solvent is 0.0003 to 0.03 mol / L, The spherical silica-based mesoporous material according to any one of claims 1 to 3 is obtained by setting the concentration of the silica raw material to 0.0005 to 0.03 mol / L in terms of Si concentration. A method for producing a spherical silica mesoporous material. A first step of mixing a silica raw material and a surfactant in a solvent to obtain porous precursor particles obtained by introducing the surfactant into the silica raw material;
A second step of obtaining a spherical silica-based mesoporous material by removing the surfactant contained in the porous material precursor particles;
A third step of graft polymerizing an organic alkoxysilane containing a 3-aminopropyl group to the spherical silica-based mesoporous material;
A method for producing a spherical silica-based mesoporous material containing the following general formula (1) as the surfactant:
[Wherein R ¹ , R ² and R ³ may be the same or different and each represents an alkyl group having 1 to 3 carbon atoms, X represents a halogen atom, and n represents an integer of 9 to 25, respectively. ]
Is used, an aqueous solvent having an alcohol content of 80% by volume or less is used as the solvent, and the concentration of the surfactant in the solvent is 0.0003 to 0.03 mol / L, The spherical silica-based mesoporous material according to any one of claims 1 to 3 is obtained by setting the concentration of the silica raw material to 0.0005 to 0.03 mol / L in terms of Si concentration. A method for producing a spherical silica mesoporous material.   A base catalyst comprising the spherical silica-based mesoporous material according to any one of claims 1 to 3.