JP2002234712A - Porous material, method for producing the same and catalyst using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a porous material having sufficiently high catalytic activity and enabling reduction of catalytic reaction time and the amount of a catalyst used and to provide a method for producing the porous material and a catalyst using the porous material. SOLUTION: The porous material comprises a compound having a basic framework in which zirconium and phosphorus atoms bond to each other by way of an oxygen atom and not having a crosslinked structure of an organic group and has pores having 0.3-2 nm median pore diameter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a porous material, a method for producing the same, and a catalyst comprising the same.

[0002]

2. Description of the Related Art Zeolite is conventionally known as a crystalline porous substance. Zeolite has uniform pores (micropores) having a central pore diameter of 0.3 to 1.3 nm based on its crystal structure, and is widely used as a catalyst or an adsorbent because of its unique surface characteristics and adsorption characteristics. I have. Zeolites generally have a basic skeleton consisting of silicon atoms, aluminum atoms and oxygen atoms, but recently, titanosilicate zeolites have a crystalline porosity consisting of silicon atoms, titanium atoms and oxygen atoms. The substance was synthesized.

[0003] Typical examples of the titanosilicate zeolite include those called TS-1 and TS-2. These titanosilicate zeolites have a medium strength solid acidity. It has been reported to exhibit catalytic activity in organic synthesis reactions and photocatalytic reactions in the liquid phase.

In recent years, mesoporous substances having pores larger than zeolite (mesopores, central pore diameter: 1.5 to 50 nm) and having very high uniform pore diameter have also been synthesized. (CT Kresge et al., Natur
e, vol.359, p710, 1992; S. Inagaki et al., J. Che
m. Soc., Chem. Commun., 680. 1993).

[0005] The above-mentioned zeolites and mesoporous substances have a silicate skeleton (O-Si-O) as a basic skeleton. In recent years, studies on a porous substance made of an inorganic compound having a basic skeleton other than the silicate skeleton have been actively conducted. It has been done. One example is a porous material made of a zirconium-phosphorus composite oxide, and a technique for synthesizing a porous material made of zirconium phosphate and having pores having a center pore diameter of about 2.5 to 2.7 nm ( Jose Jim
enez-Jimenez et al., Adv. Mater., 10, No. 10, p812,
1998) and a technology for introducing an organic group into a layered compound composed of zirconium phosphate to form a pillared (G.
Alberti et al., Microporous and Mesoporous Materi
als 21, p297, 1998).

[0006]

However, the catalytic activity of the above-mentioned conventional porous material is not sufficient, and it takes a long time to obtain a sufficient amount of reaction product in the catalytic reaction. Since a large amount of catalyst is required, there has been a problem that the cost increases and the kind of applicable catalytic reaction is limited.

The present invention has been made in view of the above-mentioned problems of the prior art, has sufficiently high catalytic activity, and is capable of sufficiently reducing the time required for the catalytic reaction and the amount of the catalyst used. It is an object of the present invention to provide a possible porous material, a method for producing the same, and a catalyst using the porous material.

[0008]

Means for Solving the Problems The present inventors have made intensive studies to achieve the above object, and as a result, have found that an organic group having a basic skeleton in which a zirconium atom and a phosphorus atom are bonded via an oxygen atom. It has been found that the above problems can be solved by a porous substance comprising a compound having no crosslinked structure and having a central pore diameter within a specific range, and the present invention has been completed.

That is, the porous substance of the present invention comprises a compound having a basic skeleton in which a zirconium atom and a phosphorus atom are bonded via an oxygen atom and having no cross-linking structure of an organic group. Has pores of 0.3 to 2 nm.

The porous substance of the present invention comprises a compound having a basic skeleton in which a zirconium atom and a phosphorus atom are bonded via an oxygen atom and having no organic group cross-linking structure as described above. A large amount of zirconium atoms contributing to the reaction can be incorporated into the porous material, and when used as a catalyst, sufficiently high catalytic activity can be obtained. In addition, the porous substance of the present invention has pores whose central pore diameter is within the above specific range, and therefore has a sufficiently large surface area and can provide a large number of reaction sites. , A sufficiently high catalytic activity can be obtained.

In the porous material of the present invention, the value obtained by dividing the total volume of pores having a diameter within the range of ± 40% of the central pore diameter by the total volume of pores is 0.4 to 1. Preferably, there is. If the pore volume satisfies the above conditions,
The pore diameter becomes very uniform, and the shape selectivity of the reaction substrate in the catalytic reaction tends to be further enhanced.

The basic skeleton is represented by the following general formula (1): ZrP _x O _y (1) [In the formula (1), x represents a number of 0.1 to 10, and y represents 2 to 10.
It represents the number of 10.]. When the porous substance of the present invention has a basic skeleton having a composition represented by the above general formula (1), the basic skeleton tends to efficiently act on a catalytic reaction, and the catalyst efficiency tends to be improved.

The catalyst of the present invention is characterized by containing the above-mentioned porous substance of the present invention. The catalyst of the present invention enables an efficient catalytic reaction even when the amount used is small, and can be suitably used as a catalyst such as a partial oxidation catalyst for organic substances and a photocatalyst.

Further, the method for producing a porous material according to the present invention is characterized in that it comprises a step of reacting a zirconium-containing compound with a phosphorus-containing compound in water in the presence of an alkyldiamine and an alcohol. . According to the production method of the present invention, the porous substance of the present invention can be obtained efficiently and reliably.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail.

The porous substance of the present invention is a compound having a skeleton in which a zirconium atom and a phosphorus atom are bonded via an oxygen atom and having no cross-linked structure of an organic group (hereinafter, referred to as a “first compound” in some cases). The first compound has a bond represented by-[Zr-OPO] _n- (n: an integer of 1 or more representing the number of repetitions) in the molecule. Since the porous substance of the present invention is composed of the first compound having such a basic skeleton, a zirconium atom as an active site (active site) of the catalyst is contained in the compound without impairing the pore structure of the porous substance. A sufficiently large amount can be taken in, and a sufficiently high catalytic activity can be obtained.

In addition, the present inventors speculate as to the mechanism by which the active site of the catalyst is expressed in the porous material of the present invention as follows. That is, it is considered that the formation of the basic skeleton in the molecule of the first compound forms a band structure in which the conduction band and the valence band are separated by an appropriate forbidden band. When energy such as heat or light is applied to the compound having such a band structure,
It is presumed that the electrons in the valence band are excited into the conduction band by the absorption of energy, and the holes in the valence band and the electrons in the conduction band respectively act as active centers of the redox reaction.

In the porous material of the present invention, both the zirconium atom and the phosphorus atom can form a four-coordinate structure or a six-coordinate structure. When a four-coordinate structure is formed, a steric bond is formed such that an oxygen atom is located at at least one of four vertexes of a tetrahedron centered on a zirconium atom or a phosphorus atom. On the other hand, when a hexacoordinate structure is formed, a steric bond is generated such that an oxygen atom is located at at least one of the six vertices of an octahedron centered on a zirconium atom or a phosphorus atom.

The valences of the zirconium atom and the phosphorus atom are 4 and 5, respectively, and those which do not participate in the bond with the oxygen atom forming the basic skeleton can bond to other atoms or functional groups. For example, a zirconium atom can form a bond with a chlorine atom, a hydroxyl group, or the like in addition to a bond with an oxygen atom forming a basic skeleton. Further, the phosphorus electron can form a bond with a chlorine atom, a hydroxyl group, an alkyl group or the like in addition to the bond with the oxygen atom forming the basic skeleton.

When the composition of the basic skeleton of the porous substance of the present invention is represented by the following general formula (1): ZrP _x O _y (1) using the ratio x, y of phosphorus atom and oxygen atom to zirconium atom. , X is a number from 0.1 to 10 and y is from 2 to
It is preferably a number of 10, more preferably x is a number of 0.7 to 1.2 and y is a number of 3 to 6. When the ratio of the phosphorus atom and the oxygen atom to the zirconium atom satisfies the above conditions, the regularity of the chemical structure of the porous material is improved, and, for example, a higher catalytic activity when used as a partial oxidation catalyst or a photocatalyst of an organic compound. Tends to be obtained.

The porous substance of the present invention has pores having a central pore diameter of 0.3 to 2 nm. When the center pore diameter of the pores is within the above range, the porous substance exhibits sufficiently high adsorptivity to the starting compound for the catalytic reaction, and the starting compound is sufficiently present in the pores where the active sites exist. It is introduced at a high concentration to improve the reaction rate. Further, in such fine pores, a strong potential field is formed by the van der Waals force from the pore walls overlapping and acting in a three-dimensional manner. The reaction rate is improved. Further, the surface area of the porous material of the present invention having such pores is sufficiently large, so that a sufficiently large number of reaction sites can be provided. Therefore, the porous substance of the present invention makes it possible to sufficiently reduce the time for the catalytic reaction and the amount of the catalyst used.

Here, the central pore diameter according to the present invention is a value (d) obtained by differentiating the pore volume (V) by the pore diameter (D).
V / dD) refers to the pore diameter at the maximum peak of a curve (pore diameter distribution curve) plotting pore diameter (D). The pore size distribution curve can be determined by the method described below. That is, the porous body is cooled to liquid nitrogen temperature (−196 ° C.), nitrogen gas is introduced, the adsorption amount is determined by a constant volume method or a weight method, and then the pressure of the introduced nitrogen gas is gradually increased. The adsorption amount of nitrogen gas is plotted against each equilibrium pressure to obtain an adsorption isotherm.
Using this adsorption isotherm, the Cranston-Inklay method, Pollimore
-A pore size distribution curve can be obtained by a calculation method such as the Heal method or the BJH method.

In the porous material of the present invention, the value obtained by dividing the total volume of pores having a diameter within the range of ± 40% of the central pore diameter by the total volume of pores is 0.4 to 1%. It is preferred that When the pore volume does not satisfy the above conditions, the uniformity of the pore diameter becomes insufficient, and the shape selectivity of the reaction substrate in the catalytic reaction tends to decrease.

Further, the pore volume of the porous material of the present invention is preferably 0.05 to 0.5 ml / g, more preferably 0.1 to 0.5 ml / g. When the pore volume is less than the lower limit, the volume of the pores in the porous material becomes small, for example, when performing a water decomposition reaction using the porous material as a photocatalyst, the number of reaction sites is reduced and the catalyst becomes Activity tends to decrease. On the other hand, when the pore volume exceeds the upper limit, the void portion in the porous material tends to increase excessively, and the strength of the porous material tends to decrease. The pore volume can be determined from the above adsorption isotherm.

The porous substance of the present invention has a basic skeleton in which a zirconium atom and a phosphorus atom are bonded via an oxygen atom. As described above, in the basic skeleton, the zirconium atom has a four-coordinate structure. Alternatively, it can have a six-coordinate structure, and the phosphorus atom can also have a four- or six-coordinate structure. Although the present inventors do not wish to be bound by any theory, when both the zirconium atom and the phosphorus atom take a four-coordinated structure, ZrXPO ₄ (X is Cl ⁻ , OH ^- or the like), and when the zirconium atom has a four-coordinate structure and the phosphorus atom is bonded to double-bonded oxygen, the structure of ZrHPO ₄ is contained in the porous material. Is considered to be formed.

Since the valences of the zirconium atom and the phosphorus atom are 4, 5, respectively, it is considered that the phosphorus atom in the structure of ZrXPO ₄ is positively charged and forms an ion pair with X having a negative charge. Can be Therefore, it is considered that when both the zirconium atom and the phosphorus atom have a four-coordinate structure in the porous material of the present invention, the porous material exhibits anion exchange characteristics. In this case, the porous substance of the present invention has the following formula (2):

[0027]

Embedded image It has a structure represented by

[0028] In the above formula (2), X ^- as the anion represented by, for example, derived from a variety of compounds used in the synthesis of porous material (surfactant, pH adjusting agents, etc.) O
H ^- like anion, Cl from desorbed various compounds during synthesis (four hydrogen chloride eliminated by the reaction of zirconium chloride and phosphoric acid, etc.) ^- is anion and the like.

When a porous material having a structure represented by the above formula (2) is brought into contact with a solution containing an anion, this solution penetrates into the pores of the porous material and the like, and the solution contains an anion. It represents an anion exchange properties happening exchange between ^- ion and X. At this time, the ion exchange dose is 0.01 to 10 m
It is preferably mol.

In the structure of ZrHPO ₄ , PO—O
There is a bond H, in which H ⁺ exhibits strong solid acidity by being polarized like P—O ⁻ H ⁺ . Therefore, in the porous material of the present invention, 4 zirconium atoms are required.
It is considered that when a phosphorus atom has a coordination type structure and bonds to a double bond oxygen, it exhibits cation exchange characteristics. In this case, the porous substance of the present invention has the following formula (3):

[0031]

Embedded image It has a structure represented by

The structure represented by the above formula (3) is neutral as a whole, but the hydroxyl group bonded to the phosphorus atom can be polarized like P—O ⁻ H ⁺ as described above. By bringing the porous material having the structure represented by 3) into contact with a solution containing a cation, this solution penetrates into the pores of the porous material and exchanges cations in the solution with H ^+. Occurs to indicate cation exchangeability. At this time, the ion exchange dose is preferably 0.01 to 10 mmol / g.

The porous substance of the present invention is represented by the above formula (2)
Or, having the structure represented by (3) can be confirmed by a conventionally known analysis method. For example, the presence of a PO-Zr bond can be confirmed by an infrared absorption spectrum, and the zirconium atom can be confirmed to have a four-coordinate structure or a six-coordinate structure by an ultraviolet / visible absorption spectrum. In addition, it can be confirmed from the ³¹ P MAS NMR spectrum that the phosphorus atom has a four-coordinate structure or a six-coordinate structure.

The porous substance of the present invention having the above-mentioned constitution can be obtained efficiently and reliably by the production method of the present invention described later.

That is, the method for producing a porous substance of the present invention is characterized in that it comprises a step of reacting a zirconium-containing compound with a phosphorus-containing compound in water in the presence of an alkyldiamine and an alcohol. .

The zirconium-containing compound used in the production method of the present invention is not particularly limited as long as it can react with a phosphorus-containing compound to form a basic skeleton in which a zirconium atom and a phosphorus atom are bonded via an oxygen atom. Although not specifically mentioned, specifically, zirconium tetrachloride (ZrC
l ₄ ), zirconium tetraisopropoxide (Zr
(OiPr) ₄ ), zirconium alkoxide, zirconium acetylacetonate, sulfated zirconia and the like. One of these zirconium-containing compounds may be used alone, or two or more thereof may be used in combination.

The phosphorus-containing compound is not particularly limited as long as it can react with the zirconium-containing compound to form a basic skeleton in which a zirconium atom and a phosphorus atom are bonded via an oxygen atom. Include phosphoric acid (H ₃ PO ₄ ), phosphate ester and the like. One of these phosphorus-containing compounds may be used alone, or two or more thereof may be used in combination. In addition, the phosphorus-containing compound, in addition to the above compounds, an alkylphosphonic acid and / or
Or you may further contain an alkyl phosphonic acid ester. The alkyl group of the alkylphosphonic acid or the alkylphosphonic ester may be linear or branched. Further, the alkyl group preferably has 1 to 10 carbon atoms.

When the phosphorus-containing compound further contains an alkylphosphonic acid and / or an alkylphosphonic ester in addition to phosphoric acid or a phosphoric ester, the basic skeleton of the resulting porous substance has an alkyl group bonded to a phosphorus atom. , And the hydrophobicity of the porous substance tends to be increased. It is preferable that the ratio of the phosphorus atom derived from the alkylphosphonic acid and / or the alkylphosphonic ester to all the phosphorus atoms contained in such a phosphorus-containing compound is 50% or less in terms of molar amount.

The amount of the zirconium-containing compound and the phosphorus-containing compound used is appropriately selected according to the composition (ZrP _x O _y ) of the basic skeleton of the target porous substance, and the total amount of zirconium atoms in the zirconium-containing compound is determined. The ratio of the total number of moles of phosphorus atoms in the phosphorus-containing compound to the number of moles is preferably from 0.1 to 10, more preferably from 0.7 to 10.
1.2. The concentration of these compounds in water is not particularly limited, but is preferably 0.1 to 20 mol% in total of the zirconium-containing compound and the phosphorus-containing compound.

In the production method of the present invention, an alkyl diamine is used as a template. As such an alkyldiamine, specifically, 1,12-
Diaminododecane, 1,10-diaminodecane, 1,8
Examples thereof include -diaminooctane and 1,6-diaminohexane, and among them, an alkyldiamine having an alkyl group having 8 to 14 carbon atoms is preferable. Further, the amount of the alkyldiamine used is preferably 0.1 to 20% by mole based on the total number of moles of the zirconium-containing compound and the phosphorus-containing compound.

In the production method of the present invention, when a zirconium-containing compound and a phosphorus-containing compound are reacted in water in the presence of an alkyldiamine, the crystallinity of a porous substance obtained by using an alcohol is improved. Can be. Specific examples of such alcohols include methanol, ethanol, n-propanol, i-
And propanol. These alcohols are 1
The seeds may be used alone, or two or more kinds may be used in combination. The amount of the alcohol used is preferably 0.3 to 1 mol, more preferably 0.5 to 1 mol, per 1 mol of the phosphorus-containing compound.

The reaction temperature in the production method of the present invention is not particularly limited, and the reaction may be carried out at room temperature or with heating. When the reaction temperature is room temperature, the reaction is preferably performed for 1 hour to 3 days while stirring the reaction solution. When heating, 40 to 150 ° C using an autoclave or the like.
For 1 hour to 3 days.

Further, in the production method of the present invention, the reaction solution is prepared using ammonia water or an aqueous sodium hydroxide solution.
It is preferable to adjust H to 2 to 6. When the pH value of the reaction solution is within the above range, a porous substance having higher crystallinity tends to be obtained.

In the production method of the present invention, after a step of reacting a zirconium-containing compound and a phosphorus-containing compound in water in the presence of an alkyldiamine and an alcohol is carried out, the alkyl present in the pores of the porous substance is obtained. The method may further include a step of removing the diamine.

Examples of the method for removing the alkyldiamine include a method involving calcination and a method involving treating with a solvent such as water or alcohol. The firing temperature in the firing method is usually 300 to 1000 ° C., preferably 400 to 7 ° C.
00 ° C. The firing time is appropriately selected according to the firing temperature, but is usually about 30 minutes, preferably 1 hour or more. The firing may be performed in the air, but is preferably performed in an atmosphere of an inert gas such as nitrogen since a large amount of combustion gas is generated during the firing. In the method of treating with a solvent, it is preferable to use a solvent having high solubility in alkyldiamine.

As described above, the porous substance of the present invention has the above-mentioned composition and chemical structure, and the catalyst of the present invention using the porous substance can be suitably used in a wide range of fields. As an application field of the catalyst of the present invention,
Specifically, partial oxidation of organic matter, production of hydrogen by photolysis of water, and organic compounds (methane,
Photo-synthesis of methanol, etc.) (immobilization of carbon dioxide), photo-purification of nitrogen oxides (NOx), antifouling building materials, antibacterial materials, superhydrophilic materials, superhydrophobic materials, deodorant / deodorant amounts, dioxin and Photodegradation of environmentally harmful substances such as environmental hormones, freshness retention material by ethylene degradation, water treatment material (removal of Escherichia coli, organochlorine compounds, pesticides, phenol, etc.) Use and the like.

[0047]

EXAMPLES Hereinafter, the present invention will be described more specifically based on Examples and Comparative Examples, but the present invention is not limited to the following Examples.

EXAMPLE 1 In 70 ml of a mixed solution of isopropanol and water (weight ratio of isopropanol to water: 1/1), 23.4 g of 1,12-diaminododecane as a template and phosphoric acid (H ₃ PO ₄₎ ) And stirred vigorously.

Next, a mixture of zirconium tetrapropoxide (Zr (OPr) ₄ : Pr represents a propyl group) and isopropanol (weight ratio of zirconium tetrapropoxide to isopropanol: 1/1) 77.2
g is gradually added to the above mixture.
And hydrothermally treated at 60 ° C. (333 K) for 1 day under normal pressure to obtain a gel-like substance. The molar ratios of the constituent components of the obtained gel-like substance were as follows.

Zr (OPr) ₄ : H ₃ PO ₄ : R: H ₂ O =
1: 1: 0.25: 100 where R represents a template (1,12-diaminododecane).

The gel material was filtered, and the obtained solid was washed with water and dried at room temperature to obtain a template-containing porous material. 2 g of the porous material containing the template
g of diluted hydrochloric acid (2 mol%) and 100 ml of ethanol, and the resulting mixture was refluxed at 40 ° C. (313 K) for 4 hours to remove the template, thereby obtaining a desired porous substance.

(X-Ray Fluorescence Analysis) X-ray fluorescence analysis of the porous material after the removal of the template revealed that the chemical composition was Zr ₁ P ₁ O _4.5 .

(Measurement of X-ray diffraction spectrum) RINT-
Using a 2200 (Rigaku Corp., X-ray: CuKα ray), powder X-ray diffraction measurement of the porous material containing the template and the porous material after removing the template was performed.

FIGS. 1a and 1b are graphs showing the diffraction patterns of the porous material after removal of the template, respectively.
Is a diffraction pattern in the Bragg angle range of 2θ = 2 to 50 °, and b is an enlarged view of a portion of 2θ = 2 to 10 °. In FIG. 1, a diffraction peak is observed in a low angle range of 2θ <10 °, but a characteristic diffraction peak is observed in a range of 2θ = 10 ° to 50 °. The obtained porous substance has a long periodic structure. Only, and it was confirmed that the pore walls had an amorphous structure. Further, d ₁₀₀ of the template-containing porous material is 2.65 nm, d ₁₀₀ of the porous material after template removal was found to be 2.42nm.

(Nitrogen Adsorption) The porous material after removing the template was cooled to liquid nitrogen temperature (−196 ° C.), nitrogen gas was introduced, and the amount of adsorption was measured by a volumetric method. Next, the pressure of the nitrogen gas to be introduced was gradually increased, and the adsorption amount of the nitrogen gas with respect to each equilibrium pressure (P / P ₀ ) was plotted to obtain a nitrogen adsorption isotherm. Based on the adsorption isotherm, a pore diameter distribution curve was obtained by the SF method (Saito-Foley method), and the pore diameter at the maximum peak was defined as the central pore diameter. FIG. 2 shows the obtained adsorption isotherm, and FIG. 3 shows the pore size distribution curve.

From the adsorption isotherm shown in FIG. 2, it was found that the obtained porous substance was a mesoporous substance and had a BET specific surface area of 275 m ² / g. Note that this B
The value of the ET specific surface area is larger than conventionally known layered zirconium phosphate (BET specific surface area: about 10 to 50 m ² / g). Further, the central pore diameter of this porous material was 1.1 nm.

(Measurement of ³¹ P MAS NMR spectrum) Using MSL-300WB (manufactured by Bruker) and phosphoric acid (H ₃ PO ₄ ) as a standard sample, porous material containing template and porous material after removing the template The ³¹ P MAS NMR spectrum of the active substance was measured. FIG. 4 shows the obtained results.

In any of the spectra shown in FIG. 4, a signal based on P (OZr) ₄ was detected at around -30 to -5 ppm, and in these porous substances, a zirconium atom and a phosphorus atom were linked via an oxygen atom. It was confirmed that the compound had a basic skeleton bonded by bonding. Further, in the spectrum of the template-containing porous substance shown in FIG.
A signal near 0 ppm, a signal near -10.8 ppm, and a signal near -16.5 ppm are each assigned to a phosphorus atom having a tetracoordinate structure. Further, in the spectrum of the porous material after the template removal,
Chemical shift from around -10.8 ppm to around -12.6 ppm and -20.0 pp from around -16.5 ppm
A chemical shift around m was observed, and no signal around -7.0 ppm was observed. Such a chemical shift and the disappearance of the signal are caused by the removal of P-
O ^- from NR ₄ ⁺ P-O ^- protonation of the H ⁺ (proto
nation).

(Measurement of FT-IR spectrum) FT / I
Using R-5M (manufactured by JASCO Corporation), the FT of the porous material containing the template and the porous material after removing the template was used.
-IR spectrum was measured.

FT-IR of porous material containing template
The spectrum is shown in FIG. In FIG. 5, the absorption at 3420 cm ⁻¹ is the O—H stretching vibration of P—OH, the absorption at 1630 cm ^{−1 is} the bending vibration of the adsorbed water, the absorption at 1120 to 1020 cm ⁻¹ and 525 cm ⁻¹ is P—O −. It is attributed to the vibration of the Zr skeleton. Also, 3200 to 30 shown in FIG.
The absorption at 40 cm ^-1 is CH stretching vibration, 2920-285
The absorption at 0 cm ^-1 is NH stretching vibration, 1510 to 1390
Although the absorption at cm ^-1 is attributed to the NH bending vibration, these absorptions were not observed in the spectrum of the porous material after removing the template.

(Scanning Electron Microscope Observation) JSM-890
The scanning electron microscope (SEM) observation of the porous material containing a template was performed using (manufactured by JOEL). The photograph shown in FIG. 6 was taken at a magnification of 20000. FIG.
Has a particle size of 40, as found in microporous materials.
The figure shows a spherical crystal having a particle size of 0.2 to 0.3 μm constituted by aggregation of fine particles of 示 60 μm.

(Estimation of Mechanism of Formation of Basic Skeleton in Porous Material) Based on the above results, it was presumed that the basic skeleton was formed in the obtained porous material by the reaction route shown in FIG. .

That is, in the presence of phosphoric acid, two amino groups of 1,12-diaminododecane are protonated to
NH ₃ ^+, and the hydrophobic moiety mainly, the spheroids balanced by aggregated as hydrophilic moiety outwardly oriented, further outside of -NH ₃ ⁺ charges phosphate ions (PO ₄ ^3-) Form. When zirconium tetrapropoxide is added to the spheroid, zirconium is quickly arranged near the phosphate ions of the spheroid, and the PO is subjected to hydrothermal treatment.
It is considered that Zr is formed and a template-containing porous material is obtained (FIG. 7A).

When the template-containing porous substance thus produced is treated with a hydrochloric acid / ethanol solution,
It is considered that an oxygen atom (—O ⁻ ) bonded to —NH ₃ ⁺ is protonated with the elimination of 2-diaminododecane to obtain a target porous substance (FIG. 7B). .

The above reaction mechanism is suggested by the fact that the pore diameter of the porous material after the removal of the template is in good agreement with the molecular length of 1,2-diaminododecane.

(Evaluation of catalytic activity)
Photodecomposition of water was performed using the porous material after removal of the template as a catalyst, and its catalytic activity was evaluated.

The photolysis of water was carried out using a gas phase circulation system reactor. The reaction apparatus is provided with a quartz reaction vessel having an internal volume of 400 ml, and the inside of the reaction vessel can be evacuated by a vacuum pump. An on-line gas chromatography device (detector: TCD, FID) is connected to the gas phase circulation path of the reaction device, so that the composition of the gas after a predetermined time has elapsed can be analyzed.

In such a reaction apparatus, first, an aqueous solution in which 5.3 g of sodium sulfite (Na ₂ SO ₃ ) was dissolved in 175 ml of water and 1 g of the porous substance after removing the template
Was placed in a reaction vessel and attached to the reactor. Next, after exhausting the gas in the reaction vessel and the gas phase circulation path, 60 Torr of argon gas is introduced, and while the mixture in the reaction vessel is stirred by a magnetic stirrer, light is emitted using a xenon (Xe) lamp (output: 300 W). Irradiation was performed. After a lapse of a predetermined time, the amount of hydrogen generated by the reaction was measured by a gas chromatography device.

In the above reaction, the amount of hydrogen generated when light irradiation was performed for 1 hour was 3.9 mmol per 1 g of the catalyst. FIG. 8 shows the correlation between the reaction time and the amount of generated hydrogen when this cycle is repeated three times until 24 hours after the start of light irradiation. The amount of hydrogen generated in 1 to 3 cycles was 84.2 mm / g of catalyst.
ol, 82.7 mmol, and 81.8 mmol, and it was confirmed that the porous substance used had sufficiently high catalytic activity over a long period of time. Note that oxygen was not detected in the above reaction.

Comparative Example 1 Water photolysis was carried out in the same manner as in Example 1 except that the porous material after removing the template was not used.
The amount of hydrogen generated by light irradiation for 24 hours is 10.7 mmol
Met.

[0071]Comparative Example 2 Instead of porous material after template removal,
Tania (Pt / TiO _Two) And sulfurous acid
Sodium carbonate (Na_TwoCO_Three)
Photolysis of water was carried out in the same manner as in Example 1 except that it was used.
However, the amount of hydrogen generated by light irradiation for one hour
It was 0.57 mmol per g.

Comparative Example 3 The same as Example 1 except that zirconia (ZrO ₂ ) was used instead of the porous material after the template was removed, and sodium hydrogen carbonate (NaHCO ₃ ) was used instead of sodium sulfite. When the water was subjected to photolysis, the amount of hydrogen generated by light irradiation for 1 hour was 0.31 mmol per 1 g of the catalyst.

[0073]

As described above, the porous substance of the present invention has a sufficiently high catalytic activity and can sufficiently reduce the time required for the catalytic reaction and the amount of the catalyst used. is there. Further, the porous material of the present invention can be obtained efficiently and reliably by the production method of the present invention.
Furthermore, the catalyst of the present invention using the porous material of the present invention sufficiently reduces the time for the catalytic reaction and the amount of the catalyst used in a wide range of fields such as partial oxidation of organic substances and photolysis of water. At the same time, a sufficiently high catalytic activity can be obtained.

[Brief description of the drawings]

FIG. 1 is a graph showing a diffraction pattern of a porous material obtained after removing a template obtained in Example 1, where a is a diffraction pattern in the range of Bragg angle 2θ = 2 to 50 °, b
Is an enlarged view of the portion of 2θ = 2 to 10 ° of a.

FIG. 2 is a graph showing an adsorption isotherm of a porous substance obtained in Example 1 after removing a template.

FIG. 3 is a graph showing a pore size distribution curve of a porous substance obtained in Example 1 after removing a template.

FIG. 4 shows ³¹ P MAS of the porous material containing a template obtained in Example 1 and the porous material after removing the template.
It is a graph which shows an NMR spectrum.

FIG. 5 is a graph showing an FT-IR spectrum of the template-containing porous substance obtained in Example 1.

FIG. 6 is a scanning electron micrograph of the template-containing porous material obtained in Example 1.

FIG. 7 is a reaction route diagram showing an assumed reaction mechanism when synthesizing the porous substance of the present invention from a zirconium-containing compound and a phosphorus-containing compound.

FIG. 8 is a graph showing the correlation between the light irradiation time and the amount of generated hydrogen in the photolysis of water using the porous material obtained in Example 1 after removing the template.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4G069 AA02 AA08 AA09 AA11 AA12 BB06A BB06B BD07A BD07B BD07C CC33 DA06 EC11X EC11Y EC12X EC12Y EC13X EC13Y FB08 FB29 FB77 4G073 BA21 BA70 BA75 BB24 BB43 FC01

Claims (5)

[Claims] 1. A compound having a basic skeleton in which a zirconium atom and a phosphorus atom are bonded via an oxygen atom and having no cross-linking structure of an organic group, and having a central pore diameter of 0.3 to
A porous material having pores of 2 nm. 2. The value obtained by dividing the total volume of pores having a diameter in the range of ± 40% of the central pore diameter by the total volume of pores is 0.4 to 1. The porous substance according to claim 1. 3. The basic skeleton is represented by the following general formula (1): ZrP _x O _y (1) [In the formula (1), x represents a number of 0.1 to 10, and y represents 2 to 10.
The porous material according to claim 1 or 2, wherein the composition has a composition represented by the following formula: 4. A catalyst comprising the porous substance according to claim 1. Description: 5. A method for producing a porous material, comprising a step of reacting a zirconium-containing compound and a phosphorus-containing compound in water in the presence of an alkyldiamine and an alcohol.