JP2018145044A - Transition metal carried aei type silico-alumino-phosphate and catalyst for nitrogen oxide purification treatment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transition metal-supported AEI type SAPO having high water resistance and a catalyst for nitrogen oxide purification treatment. SOLUTION: A group consisting of Ti, Fe, Co, Ni, Cu, Zn, Ga, Zr, Mo, W, Pt, Au, and Ce in a zeolite having at least a silicon atom, a phosphorus atom, and an aluminum atom in a skeleton structure. A transition metal-supporting AEI-type siliconaluminophosphate carrying at least one transition metal selected from the above. The transition metal carrying amount of the zeolite is 0.5% by weight or more and 10.0% by weight or less, and the molar ratio x of the silicon atom to the total of the silicon atom, the aluminum atom and the phosphorus atom in the zeolite skeleton structure is 0.01 to 0.01. It is 0.20, the average primary particle diameter obtained from the SEM image is 1 μm or more and 50 μm or less, and the ratio of the median diameter obtained from the particle size distribution to the average primary particle diameter is 10 or less. [Selection diagram] Fig. 1

Description

  The present invention relates to a transition metal-supported AEI-type silicoaluminophosphate (hereinafter referred to as “AEI-type SAPO”) and a nitrogen oxide purification treatment catalyst having high water resistance.

Silicoaluminophosphate (hereinafter “SAPO”) was developed in 1984 by Union Carbide (UCC). This SAPO forms a three-dimensional skeleton structure with tetrahedrons of PO ₂ ⁺ , AlO ₂ ⁻ and SiO ₂ .

  Among the above-mentioned SAPO, there is a report example that AEI-type SAPO is a useful catalyst. For example, in Non-Patent Document 1, AEI-type SAPO has a higher conversion rate of lower olefin than CHA-type SAPO in MTO reaction and has a long life. Has been reported as a long catalyst. Non-Patent Document 2 describes that the life of AEI-type SAPO has a property that the acid strength is slightly lower than that of CHA-type SAPO, which is because pore clogging due to coking is suppressed.

  Non-Patent Document 3 reports that AEI-type SAPO supporting Cu exhibits high activity as a catalyst for selective catalytic reduction (SCR) of nitrogen oxide (Nox).

  AEI type SAPO has a problem of low water resistance. For example, Patent Document 1 reports that AEI-type SAPO has a low acid amount maintenance rate in a steam atmosphere and low water resistance. Therefore, AEI-type SAPO has a relatively low skeleton density and a large pore volume, so that it is expected to show high performance as a desiccant, an adsorbent, etc., but the desiccant and the adsorption heat pump (AHP) It is not suitable as a water adsorbing and desorbing agent used for the above.

  When SAPO is used as a catalyst or adsorbent, the powder is often slurried and applied to a honeycomb for holding. The heat of adsorption at the time of slurrying and the desorption of water during drying and firing after application of the honeycomb reduces the crystallinity of SAPO. The SAPO described in Non-Patent Document 5 changes the bond angle and bond length of skeleton element-bonded Si—O—Al and P—O—Al due to the adsorption and desorption of water. By the adsorption / desorption of water, the skeleton element-bonded Si—O—Al and P—O—Al are decomposed, and the structure of the zeolite skeleton is destroyed. If the structure of the zeolite skeleton is destroyed, the catalytic activity is further reduced due to a reduction in the catalyst surface area.

  As described in Non-Patent Documents 5 and 6, when SAPO is used as an exhaust gas purification catalyst, high catalyst performance can be obtained by supporting a transition metal such as iron or copper on zeolite.

  As shown in Non-Patent Document 7, Cu-supported AEI-type SAPO is widely known as an SCR catalyst. Although the pore diameter is the same as that of Cu-supported CHA-type SAPO used industrially, it has higher high-temperature steam durability.

  When diesel oil burns in a diesel engine, hydrocarbon (hereinafter referred to as HC), particulate matter (hereinafter referred to as PM), NOx, water vapor and the like are generated. The generated water vapor is condensed in the exhaust gas treatment system and adsorbed on the exhaust gas purification catalyst when the exhaust gas temperature is lowered when the engine is stopped or idling. When the adsorbed water is desorbed, the zeolitic acid sites are cleaved and the catalytic performance is lowered. Therefore, an exhaust gas purification catalyst having high water resistance has been demanded.

  Moreover, it cannot be said that the synthesis method of AEI type SAPO has been sufficiently studied. For example, in the method using tetraethylammonium hydroxide (TEAOH) as a template as shown in Non-Patent Document 9, the synthesis time is long and a high temperature of 200 ° C. or higher is required. A method using N, N-diisopropylethylamine (DIEA) shown in Non-Patent Document 9 and Patent Document 1 as a template is currently most widely used. Although this method is superior to the above-described method using TEAOH in that it can be synthesized at a relatively mild synthesis temperature of 160 to 180 ° C., it takes time to synthesize. In any of the methods, the produced AEI type SAPO crystal has a very small particle size, so it takes time for filtration, the productivity is very low, and it is not suitable for industrial production.

  Thus, in order to use the transition metal-supported AEI type SAPO as an exhaust gas purification catalyst or the like, water resistance is required. Therefore, there is a demand for transition metal-supported AEI type SAPO having superior water resistance, which has not been obtained conventionally.

JP 2014-141385 A

Industrial & Engineering Chemistry Research, Vol. 44, p. 6605 (2005) Applied Catalysis A: General, Vol. 283, p. 197 (2005) Microporous and Mesoporous Materials, Vol. 215, p. 154 (2015) Microporous and Mesoporous Materials Vol. 57, p. 157 (2003) Journal of the Chemical Society, Chemical Communications, 1272 (1986) Applied Catalysis B: Environmental 102 (2011) 441-448 Journal of Catalysis 319 (2014) 36-43 Applied Catalysis, A, General, Vol. 142 p. L197 (1996) Journal of Physical Chemistry, Vol. 98, p. 10216 (1994)

  An object of the present invention is to provide a transition metal-supported AEI type SAPO having high water resistance and a catalyst for purifying nitrogen oxides.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have supported a transition metal having a Si / (Al + Si + P) molar ratio of 0.01 or more and 0.20 or less and an average primary particle diameter of 1 μm or more. It has been found that the water resistance of AEI type SAPO is high. The present inventors have also made it possible to use SAPO having high water resistance at a high purity and industrially when two or more kinds from a specific compound group are used in combination as a template used in hydrothermal synthesis of AEI type SAPO. It has been found that it can be produced in synthesis time.

The present invention is based on such knowledge, and the gist thereof is as follows.
[1] From a group consisting of Ti, Fe, Co, Ni, Cu, Zn, Ga, Zr, Mo, W, Pt, Au, and Ce in a skeleton structure containing at least a silicon atom, a phosphorus atom, and an aluminum atom. A transition metal-supported AEI type SAPO supporting at least one selected transition metal,
(1) The amount of transition metal supported on the zeolite is 0.5 wt% or more and 10.0 wt% or less,
(2) The molar ratio x of silicon atoms in the total of silicon atoms, aluminum atoms and phosphorus atoms in the zeolite framework structure is 0.01 to 0.20,
(3) The average primary particle diameter obtained from the SEM image is 1 μm or more and 50 μm or less,
(4) A transition metal-supported AEI type SAPO, wherein the ratio of the median diameter obtained from the particle size distribution to the average primary particle diameter is 10 or less.
[2] The transition metal-supported AEI type SAPO according to [1], wherein the transition metal contains at least Cu or Fe.
[3] The transition metal-supported AEI SAPO as described in [1], wherein the transition metal is Cu.
[4] The transition metal-supported AEI SAPO according to any one of [1] to [3], wherein the transition metal-supported amount is 1.0% by weight or more and 7.0% by weight or less.
[5] The transition metal-supported AEI type SAPO according to any one of [1] to [4], wherein a molar ratio x of the silicon atoms is 0.03 to 0.15.
[6] The transition metal-supported AEI type SAPO according to any one of [1] to [4], wherein a molar ratio x of the silicon atoms is 0.04 to 0.10.
[7] A catalyst for purifying nitrogen oxides comprising the transition metal-supported AEI type SAPO according to any one of [1] to [6].

  According to the present invention, a transition metal-supported AEI type SAPO having high water resistance is provided. Such AEI-type SAPO can be widely used as a catalyst, an adsorbent, a separator, and the like.

It is an XRD pattern of AEI type SAPO of Example A1. It is a SEM image of AEI type SAPO of Example A1. It is NOx purification performance of AEI type SAPO of Example B1. It is an XRD pattern of AEI type SAPO of comparative example A1. It is a SEM image of AEI type SAPO of comparative example A1. It is NOx purification performance of AEI type SAPO of comparative example B1.

  Hereinafter, embodiments of the present invention will be described in detail. However, the following description is an example (representative example) of an embodiment of the present invention, and the contents thereof are not specified.

The transition metal-supported AEI-type silicoaluminophosphate of the present invention has a skeleton structure containing at least a silicon atom, a phosphorus atom and an aluminum atom, Ti, Fe, Co, Ni, Cu, Zn, Ga, Zr, Mo, W, A transition metal-supported AEI type silicoaluminophosphate supporting at least one transition metal selected from the group consisting of Pt, Au, and Ce, wherein the zeolite has a transition metal support of 0.5 wt% or more and 10.0 The molar ratio x of silicon atoms to the total of silicon atoms, aluminum atoms and phosphorus atoms in the zeolite framework structure is 0.01 to 0.20, and the average primary particle diameter obtained from the SEM image is 1μm to 50μm
The ratio of the median diameter obtained from the particle size distribution to the average primary particle diameter is 10 or less.

≪AEI type SAPO≫
Hereinafter, the AEI type SAPO of the present invention will be described in detail.

SAPO, as described in US Pat. No. 4,440,871, is a three-dimensional micro that is crystalline and microporous and consists of PO ₂ ⁺ , AlO ₂ ⁻ and SiO ₂ tetrahedral units. It is a compound having a porous crystal skeleton structure.

  The transition metal-supported AEI type SAPO of the present invention has an AEI structure. The AEI structure is a crystal structure that becomes an AEI structure with a structure code defined by the International Zeolite Society (IZA).

  In addition, the structure of AEI type SAPO in the present invention is determined by X-ray diffraction (hereinafter referred to as XRD).

[Si / (Al + Si + P) molar ratio]
The abundance ratio Si / (Al + Si + P) molar ratio x of silicon atoms to the total of silicon atoms, aluminum atoms and phosphorus atoms contained in the skeleton structure in the transition metal-supported AEI type SAPO of the present invention is 0.01 or more, preferably 0 0.03 or more, more preferably 0.053 or more, still more preferably 0.058 or more, and most preferably 0.063 or more. The Si / (Al + Si + P) molar ratio is 0.20 or less, preferably 0.12 or less, more preferably 0.093 or less, more preferably 0.088 or less, still more preferably 0.083 or less, and most preferably 0.80 or less. When Si / (Al + Si + P) is in the above range, the crystallinity is high, so that the heat resistance, water resistance, and high temperature steam resistance are high. Moreover, since it has sufficient acid amount, it can utilize suitably as a solid acid catalyst. If Si / (Al + Si + P) is less than 0.01, defects tend to occur in the crystal, and heat resistance and water resistance are reduced. Furthermore, it becomes SAPO with a small amount of acid. When the Si / (Al + Si + P) molar ratio is more than 0.2, the amount of acid is too large, hydrolysis from an acid point tends to occur, and water resistance decreases. Thereby, when such SAPO is used as an adsorbent, a desiccant or a solid acid catalyst, its function may be insufficient.

[Al / (Al + Si + P) molar ratio]
The abundance ratio Al / (Al + Si + P) molar ratio of aluminum atoms to the total of silicon atoms, aluminum atoms and phosphorus atoms contained in the skeleton structure in the transition metal-supported AEI type SAPO of the present invention is usually 0.3 or more, preferably 0. .35 or more, more preferably 0.4 or more, and usually 0.6 or less, preferably 0.55 or less. If Al / (Al + Si + P) is within the above range, impurities tend to be difficult to mix during synthesis.

[P / (Al + Si + P) molar ratio]
The abundance ratio P / (Al + Si + P) of phosphorus atoms with respect to the total of silicon atoms, aluminum atoms and phosphorus atoms contained in the skeleton structure in the transition metal-supported AEI type SAPO of the present invention is preferably 0.33 or more, more preferably Is 0.35 or more, more preferably 0.38 or more, and most preferably 0.4 or more, usually 0.12 or less, preferably 0.58 or less, more preferably 0.56 or less, and still more preferably 0.00. 54 or less. When P / (Al + Si + P) is not less than the above lower limit, water resistance tends to be high. Further, when z is not more than the above upper limit value, it becomes a transition metal-supported AEI type SAPO having high water resistance and a large amount of solid acid. Thereby, the function as an adsorbent, a desiccant, and a solid acid catalyst becomes high.

[Atom Me other than Si, Al, P]
In the transition metal-supported AEI type SAPO of the present invention, a part of Al and P atoms may be substituted with other atoms (Me). As other atoms (Me), for example, lithium, magnesium, calcium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, germanium, arsenic, tin, boron, zirconium, palladium, etc. However, the present invention is not limited to this. Me is preferably at least one of iron, copper, and gallium.

  The molar ratio of Me is not particularly limited, but when the molar ratio of Me to the total of Me, Al, Si, and P is m, m is usually 0 or more, preferably 0.001 or more. In general, it is 0.2 or less, preferably 0.05 or less, more preferably 0.03 or less.

  The molar ratio of Al, Si, P, and Me is energy dispersive X-ray spectroscopy (EDX), fluorescent X-ray analysis (XRF), scanning electron microscope-energy dispersive X-ray spectroscopy (SEMEDX), It can be measured by inductively coupled plasma (ICP) elemental analysis or the like. In EDX, XRF, and SEM-EDX, it is desirable to create a calibration curve using a sample in which the value of element content is obtained by chemical analysis, and to quantify it. In ICP, SAPO can be measured by dissolving it in nitric acid, hydrofluoric acid, sodium hydroxide, potassium hydroxide or the like.

[Average primary particle size]
The average primary particle size of the transition metal-supported AEI type SAPO of the present invention is 1 μm or more, preferably 1.2 μm or more, more preferably 1.5 μm or more, and most preferably 2.0 μm or more. , 50 μm or less, preferably 30 μm or less, more preferably 20 μm or less, even more preferably 15 μm or less, and most preferably 12 μm or less.

  Here, the primary particle diameter is the ferret diameter of the smallest unit particle observed by a scanning electron microscope (SEM), and the average primary particle diameter is 50 or more randomly extracted by the SEM. This is a value obtained by averaging the primary particle diameters of the primary particles. Therefore, the secondary particle diameter and average secondary particle diameter, which are the diameters of secondary particles in which a plurality of primary particles are aggregated, are different from the primary particle diameter and average primary particle diameter. SEM observation conditions are not particularly limited as long as the shape and number of crystal grains can be clearly observed, but are usually taken at a magnification of 2000 times.

  When the average primary particle diameter is 1.0 μm or more, heat resistance and water resistance are likely to be high. On the other hand, if the average primary particle diameter of the crystal of 50 μm or less, the diffusion rate of the substance in the SAPO crystal is difficult to decrease. Therefore, for example, when the SAPO of the present invention is used as a solid acid catalyst, the reaction rate is unlikely to decrease, and an increase in by-products can be suppressed. Further, when used as an adsorbent or a desiccant, the adsorption rate is unlikely to decrease.

  When the average primary particle diameter is less than 1.0 μm, the diffusion rate becomes too high, and when used as an adsorbent or a desiccant, the expansion / contraction of crystals accompanying the adsorption / desorption of the adsorbate becomes rapid. Furthermore, rapid adsorption / desorption causes rapid exotherm and endotherm, which causes further crystal expansion / contraction. As a result, the crystal structure is broken, and the adsorption capacity is lowered, so that the durability of repeated adsorption / desorption is lowered.

  In general, it is known that the expansion and contraction associated with the heat of zeolite and adsorption / desorption of adsorbate has anisotropy. For example, Journal of the Chemical Society, Chemical Communications, p. 544 (1993) (Non-Patent Document 6) shows that the change in lattice constant associated with water adsorption / desorption of CHA-type SAPO differs between the a-axis and the c-axis. Therefore, in the state of secondary particles in which the particles are aggregated, the individual primary particles forming the secondary particles expand and contract in different directions. Therefore, the connection part of each primary particle becomes easy to be destroyed by expansion and contraction accompanying temperature change and adsorption / desorption of adsorbate. Moreover, the interface newly generated by destruction has many defects and is easily hydrolyzed by water. Therefore, the agglomerated particles have low mechanical and thermal durability and water resistance. It is preferable that the AEI type SAPO of the present invention does not aggregate.

[Crystal form]
The transition metal-supported AEI-type SAPO according to the present invention preferably has 60% or more, preferably 70% or more, more preferably 80% or more, and most preferably 90% of the crystal in the form of cubic or tetragonal crystals. . If it is at least the above lower limit, the mechanical strength of the crystal is high, and when the SAPO of the present invention is subjected to processing such as granulation and molding, there is a tendency that functional deterioration due to breakage is less likely to occur.

  In this specification, a case where the average aspect ratio is 1.25 or less measured and calculated by the following <Aspect Ratio Measurement and Calculation Method> is defined as cubic crystal. The average aspect ratio is 1.25 or less, that is, cubic is most preferable.

  The aspect ratio is 3 or less, that is, the closer to the cubic shape, the higher the mechanical strength of the crystal, and it is less likely to cause functional degradation due to breakage when the AEI type SAPO of the present invention is processed such as granulation or molding. Become.

In the case of tetragonal crystal, the average aspect ratio is preferably 4 or less, more preferably 3 or less, more preferably 2.5 or less, further preferably 2 or less, and particularly preferably 1.5 or less.
<Measurement and calculation method of average aspect ratio>
The aspect ratio means a value that is 1 or more among values obtained by dividing the value of the vertical ferret diameter from the value of the horizontal ferret diameter or the reciprocal thereof. The average aspect ratio is defined as an arithmetic average of the aspect ratios of the 50 primary particles obtained from the average primary particle diameters described above.

[(Median diameter) / (average primary particle diameter)]
It is desirable that the particles of the present invention do not aggregate and the primary particle size distribution is uniform. The more uniform the crystal, the higher the mechanical strength of the crystal, and the lowering of function due to breakage is less likely to occur when processing such as granulation or molding. In addition, when there is an unreacted raw material such as a silicon atom raw material between the primary particles, structural destruction due to hydrolysis is likely to occur, and therefore, the particle is preferably not agglomerated. The ratio of the median diameter to the average primary particle diameter, that is, (median diameter) / (average primary particle diameter) is preferably 10 or less, preferably 7.5 or less, more preferably 5.0 or less, and more preferably 4 or less. More preferred is 3 or less. When all the particles do not aggregate, the median diameter and the average primary particle diameter coincide with each other, and the ratio is 1, which is most preferable.

[Specific surface area]
The specific surface area of the transition metal supported AEI type SAPO of the present invention is preferably at least 400 meters ² / g, more preferably at least 450 m ² / g, 500 meters is more preferably not less than ² / g, 550m ² / g or more is most preferred. The higher the specific surface area, the higher the catalytic activity when used as a catalyst or the like, and the higher the adsorption capacity when used as an adsorbent or desiccant.

When the specific surface area is less than 400 m ² / g, there is a possibility that the crystallinity of the transition metal-supported AEI type SAPO is low and / or the crystals are partially collapsed to block the pores. If the crystallinity is low, the crystal structure is more likely to be destroyed by expansion / contraction due to repeated adsorption / desorption of water vapor. In addition, when the crystal is partially collapsed and the pores are clogged, when the water is absorbed and desorbed, the clogged part does not adsorb and desorb, so the other parts expand and contract. There is a possibility that the crystal breaks between the closed part and the non-closed part. The specific surface area of the sample can be calculated by nitrogen adsorption measurement.

[Ion exchange site]
The transition metal-supported AEI-type SAPO of the present invention may contain a cation species capable of ion exchange with other cations, in addition to the component constituting the skeleton structure and the supported transition metal. Examples of such cationic species include protons (H ⁺ ), alkaline elements such as Li, Na, and K, and alkaline earth elements such as Mg, Ca, and Sr. Among these, H ⁺ , Mg, Ca, and Sr are preferable, H ⁺ , Ca, and Sr are more preferable, and H ⁺ and Ca are more preferable. The inclusion of H ⁺ , Ca, and Sr is preferable because an improvement in water resistance can be expected. The inclusion of H ⁺ is preferable because an improvement in heat resistance can be expected.

[Supported transition metals]
The transition metal-carrying AEI type SAPO of the present invention carries a transition metal as an active site of the catalyst separately from the components constituting the skeleton structure. The supported transition metal may be in any state such as ionicity, metal, oxide or hydroxide, but is preferably ionic or oxide. More preferably, it is ionic. Examples of the transition metal include Ti, Fe, Co, Ni, Cu, Zn, Ga, Zr, Mo, W, Pt, Au, and Ce. Among these, Ti, Fe, Ni, Cu, Pt, Au, and Ce are preferable, Fe, Cu, and Ce are more preferable, and Fe and Cu are further preferable.

  Note that “transition metal” does not necessarily mean that it is in an elemental zero-valent state. Reference to “transition metal” includes the presence state supported in AEI-type SAPO, for example, the presence state as ionic or other species.

  The amount of transition metal supported is usually 0.1% or more, preferably 0.5% or more, more preferably 1% or more, still more preferably 1.5% or more, and usually 10% by weight with respect to zeolite. % Or less, preferably 8% or less, more preferably 5% or less, and further preferably 4% or less. If it is less than the lower limit, the active point tends to decrease, and the catalyst performance may not be exhibited. If the upper limit is exceeded, metal agglomeration tends to be remarkable, and the catalyst performance may be lowered.

≪Method for producing transition metal-supported AEI type SAPO≫
The transition metal-supported AEI-type SAPO of the present invention is usually a raw material obtained by mixing an aluminum atom raw material, a phosphorus atom raw material, a silicon atom raw material (if other atomic Me is included, another atomic (Me) raw material) and a template. After the mixture is prepared, it is produced by hydrothermal synthesis and then loading the transition metal after removing the template.

[Aluminum atomic material]
The aluminum atom raw material of zeolite is not particularly limited, and is usually aluminum alkoxide such as pseudoboehmite, aluminum isopropoxide, aluminum triethoxide, aluminum hydroxide, alumina sol, sodium aluminate, etc., and pseudoboehmite is preferable.

[Raw material]
The phosphorus atom raw material of zeolite is usually phosphoric acid, but aluminum phosphate may be used.

[Silicon atom raw material]
The silicon atom raw material of zeolite is not particularly limited, and is usually fumed silica, silica sol, colloidal silica, water glass, ethyl silicate, methyl silicate, etc., and fumed silica is preferable.

[Molar ratio of silicon atom material, aluminum atom material and phosphorus atom material]
The preferred range of the molar ratio (molar ratio as an oxide) of the silicon atom raw material, the aluminum atomic raw material and the phosphorus atomic raw material is as follows. The value of SiO ₂ / Al ₂ O ₃ is usually greater than 0, preferably 0.02 or more, and usually 0.5 or less, preferably 0.4 or less, more preferably 0.3 or less. . Further, the ratio of P ₂ O ₅ / Al ₂ O _{3 on} the same basis is usually 0.6 or more, preferably 0.7 or more, more preferably 0.8 or more, usually 1.3 or less, preferably 1 .2 or less, more preferably 1.1 or less.

  The composition of the zeolite obtained by hydrothermal synthesis has a correlation with the composition of the raw material mixture, and the composition of the raw material mixture is appropriately set in order to obtain a zeolite having a desired composition.

[Seed crystal]
If desired, SAPO crystals may be added as seed crystals (seed) to the above mixture of raw materials. The kind of SAPO used as a seed is not particularly limited, but a crystal containing a double 6-membered ring as a building unit is preferable as in AEI type SAPO. Among them, FAU, AEI, and CHA type SAPO are more preferable.

[water]
The ratio of water is usually 3 or more, preferably 5 or more, more preferably 10 or more, and usually 200 or less, preferably 150 or less, more preferably 120 or less, in molar ratio with respect to the aluminum atom raw material.

[Other ingredients]
If desired, the raw material mixture may contain components other than those described above. Such components include hydroxides such as lithium, magnesium, calcium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, germanium, arsenic, tin, boron, zirconium, palladium, Salt. Among these, Preferably, hydroxides and salts, such as iron, copper, and gallium, are mentioned. Further, the raw material mixture may contain a hydrophilic organic solvent such as alcohol. The content ratio of the hydroxide and salt in the raw material mixture is usually 0.2 or less, preferably 0.1 or less in terms of molar ratio with respect to Al ₂ O ₃ . The content ratio of the hydrophilic organic solvent such as alcohol is usually 0.5 or less, preferably 0.3 or less in terms of a molar ratio with respect to water.

[template]
The template used in the present invention is preferably (A) two or more selected from amines and ammonium salts, or (B) two or more acyclic alkylamines.
(A) Two or more selected from amines and ammonium salts

<(A) Description of a template comprising two or more selected from amines and ammonium salts>
(1) Amine The type of amine is not particularly limited, but primary amines, secondary amines, and tertiary amines are preferred. The alkyl group of the alkylamine described later may partially have a substituent such as a hydroxyl group. The alkyl group preferably has 1 to 9 carbon atoms. The molecular weight of the amine is usually 30 or more, preferably 45 or more, more preferably 60 or more, and usually 250 or less, preferably 200 or less, more preferably 150 or less.

  Examples of the primary amine include isopropylamine, t-butylamine, neopentylamine, and ethylenediamine.

  Secondary amines include diethylamine, N-methyl-n-butylamine, N-methylisobutylamine, N-methyl-t-butylamine, N-methyl-n-pentylamine, N-ethyl-n-propylamine, N -Ethyl-n-butylamine, di-n-propylamine, di-n-butylamine, diisobutylamine, di-n-pentylamine, N-methylethanolamine, hexamethyleneimine, morpholine, piperidine, 3,5-dimethylpiperidine Among them, diethylamine, N-methyl-n-butylamine, N-methylisobutylamine, N-methyl-t-butylamine, N-methyl-n-pentylamine, N-ethyl-n-propylamine, N- Ethyl-n-butylamine and di-n-propylamine are preferred. Triethanolamine, N- methyl -n- butylamine, N- methyl isobutyl amine, 3,5-dimethylpiperidine, more preferably, diethylamine, N- methyl -n- butylamine, N- methyl isobutylamine is particularly preferred.

  Tertiary amines include triethanolamine, N, N-dimethylethanolamine, N-methyldiethanolamine, dimethylethylamine, diisopropylethylamine, N-methylpiperidine, N-methyl-3,5-dimethylpiperidi, among others. Dimethylethylamine, diisopropylethylamine, N-methylpiperidine, N-methyl-3,5-dimethylpiperidine are preferable, diisopropylethylamine, N-methylpiperidine, N-methyl-3,5-dimethylpiperidine are more preferable, and diisopropylethylamine is particularly preferable. preferable.

(2) Ammonium salt Although the kind of ammonium salt is not specifically limited, The alkyl ammonium salt containing a C4 or less linear alkyl group is preferable. A tubular ammonium salt having a 6-membered ring structure is preferred.

  Examples of such ammonium salts include tetramethylammonium salt, tetraethylammonium salt, tetrapropylammonium salt, tetrabutylammonium salt, N, N-dimethyl-3,5-dimethylpiperidinium salt, and the like. N, N-dimethyl-3,5-dimethylpiperidinium salt is more preferable.

  The type of salt is not particularly limited, but halide salts such as fluoride salts, chloride salts, bromide salts, and iodide salts, and hydroxide salts are preferable, and hydroxide salts are more preferable.

  As the template of (A) described above, it is preferable to use at least one tertiary amine or / and secondary amine, and it is more preferable to use a tertiary amine and a secondary amine in combination.

<(B) Description of Template Consisting of Two or More Acyclic Alkylamines>
The kind of the acyclic alkylamine is not particularly limited, but primary acyclic alkylamine, secondary acyclic alkylamine, and tertiary acyclic alkylamine are preferable. The alkyl group of the acyclic alkylamine may partially have a substituent such as a hydroxyl group. The alkyl group preferably has 1 to 9 carbon atoms. The molecular weight of the acyclic alkylamine is usually 30 or more, preferably 45 or more, more preferably 60 or more, and usually 250 or less, preferably 200 or less, more preferably 150 or less.

  Examples of the primary acyclic alkylamine include isopropylamine, t-butylamine, neopentylamine, ethylenediamine, and the like.

  Secondary acyclic alkylamines include diethylamine, N-methyl-n-butylamine, N-methylisobutylamine, N-methyl-t-butylamine, N-methyl-n-pentylamine, N-ethyl-n- Examples include propylamine, N-ethyl-n-butylamine, di-n-propylamine, di-n-butylamine, diisobutylamine, di-n-pentylamine, dimethylethylamine, and N-methylethanolamine, among which diethylamine, N -Methyl-n-butylamine, N-methylisobutylamine, N-methyl-t-butylamine, N-methyl-n-pentylamine, N-ethyl-n-propylamine, N-ethyl-n-butylamine, di-n -Propylamine is preferred, diethylamine, N-methyl-n-butylamine N- methyl isobutyl amine are more preferred.

  Tertiary acyclic alkylamines include dimethylethylamine, triethylamine, diisopropylethylamine, tri-n-propylamine, triisopropylamine, triethanolamine, N, N-dimethylethanolamine, N-methyldiethanolamine, Of these, dimethylethylamine, triethylamine, and diisopropylethylamine are preferable, and diisopropylethylamine is more preferable.

<Suitable template>
As the template, it is preferable to use at least one tertiary acyclic alkylamine or / and a secondary acyclic alkylamine. A tertiary acyclic alkylamine and a secondary acyclic alkylamine are preferably used. It is more preferable to use an amine in combination.

  The following description applies to the case where the template is any one of the above (A) and (B).

  The mixing ratio of the templates needs to be selected according to conditions.

  When two templates are mixed, the molar ratio of the two templates to be mixed is usually 1:20 to 20: 1, preferably 1:10 to 10: 1, more preferably 1: 5 to 5: 1. More preferably from 1: 3 to 3: 1, most preferably from 1: 2 to 2: 1. For example, when diisopropylethylamine and N-methyl-n-butylamine are used, the molar ratio of diisopropylethylamine / N-methyl-n-butylamine is usually 0.05 or more, preferably 0.1 or more, more preferably 0.2 or more. It is usually 20 or less, preferably 10 or less, more preferably 9 or less.

  When mixing three templates, the molar ratio of the third template is usually from 1:20 to 20: 1, preferably 1:10, relative to the sum of the two templates mixed above. 10: 1, more preferably 1: 5 to 5: 1.

  Other templates may be contained, but the other templates are usually 20% or less in molar ratio to the whole template, and preferably 10% or less.

  The order of mixing one or more templates selected from each of the two or more groups is not particularly limited, and after preparing the template, it may be mixed with other substances, and each template may be mixed with other substances. May be mixed with.

The total amount of the template is usually 0.2 or more, preferably 0.5 or more, more preferably 1 or more in terms of the molar ratio of the template to Al ₂ O ₃ when the aluminum atom raw material in the raw material mixture is represented by an oxide. Usually, it is 4 or less, preferably 3 or less, more preferably 2.5 or less.

  When a template is included in the raw material mixture, the synthesis time can be shortened, the particle size can be increased, and the water vapor resistance can be improved. SAPO can be produced efficiently.

  A technique for synthesizing a raw material mixture by mixing a plurality of templates has been actively studied in AFI type and CHA type SAPO. For example, Japanese Patent Application Laid-Open No. 2003-183020 discloses a method capable of synthesizing CHA-type SAPO with good crystallinity in a short time. As a reason why such synthesis is possible, in Japanese Patent Laid-Open No. 2003-183020, a CHA-type SAPO can be synthesized in a short time, but a template having a characteristic of low crystallization ability and a CHA phase can be obtained. It is described that the characteristics of the individual templates appear as a synergistic effect by combining templates having the characteristics that the crystallization ability is high but a long crystallization time is required.

  The advantage of manufacturing the AEI type SAPO of the present invention using a plurality of templates cannot be explained by the above-mentioned synergistic effect. For example, in the case of using a mixture of N, N-diisopropylethylamine and N-methylbutylamine as shown in the examples described later as a template, N, N-diisopropylethylamine alone becomes a template for AEI-type SAPO. However, N, N-diisopropylethylamine alone does not form AEI type, but forms CHA type SAPO (SAPO-47). In view of the above-mentioned synergistic effect, it is expected that mixed crystals and intergrowth crystals of AEI type and CHA type are obtained in this case, but surprisingly, it was a single-phase AEI type SAPO. . Furthermore, the AEI-type SAPO produced using this mixed template shows a particle shape and crystallinity that are completely different from those when D is used alone, and no features appear when D is used alone. . Further, surprisingly, by changing the mixing ratio of N-methylbutylamine and N, N-diisopropylethylamine, the number of moles of M, which is a template of CHA type SAPO, is changed to N, which is a template of AEI type SAPO, Even when the amount was larger than that of N-diisopropylethylamine, the obtained crystals were also single-phase AEI type SAPO.

  Although the reason for the above phenomenon has not been clarified, when a certain plurality of amines are combined, they form a certain aggregate in the system, and the aggregate forms a new AEI-type SAPO. One of the hypotheses is the phenomenon of working as a template for If you think that way, you can explain that the effect of individual templates does not appear. Since the amine aggregate has a three-dimensional structure very close to the cage structure of AEI, it acts as a template for a more effective AEI-type SAPO, and as a result, the AEI-type structure is further stabilized. It is considered that the crystallization time is shortened and the crystallinity is improved.

[Ingredient mixing order]
The mixing order in preparing the aqueous gel by mixing the silicon atom raw material, aluminum atomic raw material, phosphorus atomic raw material, template and water is not limited and may be appropriately selected depending on the conditions to be used. A phosphorus atom raw material and an aluminum atomic raw material are mixed together, and a silicon atom raw material and a template are mixed therewith.

[PH of raw material mixture]
The pH of the raw material mixture is usually 5 or more, preferably 6 or more, more preferably 6.5 or more, and is usually 10 or less, preferably 9 or less, more preferably 8.5 or less, and even more preferably 8 or less.

[Synthesis of zeolite by hydrothermal synthesis]
The above raw material mixture (usually an aqueous gel) is placed in a pressure vessel and maintained at a predetermined temperature under stirring or standing under self-generated pressure or gas pressure that does not inhibit crystallization. Hydrothermal synthesis is possible. The reaction temperature of hydrothermal synthesis is usually 100 ° C. or higher, preferably 120 ° C. or higher, more preferably 150 ° C. or higher, and is usually 300 ° C. or lower, preferably 250 ° C. or lower, more preferably 220 ° C. or lower. In this temperature range, in the process of raising the temperature to the highest temperature which is the highest temperature, it is preferably maintained in the temperature range from 80 ° C. to 120 ° C. for 1 hour or more, and more preferably for 2 hours or more. . When the holding time in this temperature range is less than 1 hour, the durability of the zeolite obtained by calcining the obtained template-containing zeolite may be insufficient.

  The upper limit of the time maintained at 80 to 120 ° C. is not particularly limited, but if it is too long, it may be inconvenient in terms of production efficiency, and is usually 100 hours or less, and preferably 24 hours or less in terms of production efficiency.

  The temperature rising pattern is not particularly limited, and may be, for example, a monotonically increasing pattern, a step changing pattern, a pattern changing vertically such as vibration, or a combination of these. Usually, a pattern in which the temperature rises monotonously while keeping the temperature rise rate below a certain value is preferable because of easy control.

  In the hydrothermal synthesis step, it is preferable to keep the temperature near the maximum temperature for a predetermined time. The vicinity of the maximum temperature means a temperature 5 ° C. lower than the maximum temperature or the maximum temperature. The time for maintaining the maximum temperature is usually 0.5 hours or more, preferably 3 hours or more, more preferably 5 hours or more, usually 30 days or less, preferably 10 days, depending on the composition of the raw material mixture. Hereinafter, it is more preferably 4 days or less.

  The temperature drop pattern after being held at the maximum temperature is not particularly limited, and may be any of a pattern that changes stepwise, a pattern that changes below the maximum temperature, such as vibration, and a combination of these. Usually, from the viewpoint of ease of control and durability of the obtained zeolite, it is preferable to keep the temperature at the highest temperature and then to monotonously lower the temperature from 100 ° C. to room temperature.

[Remove template]
After the hydrothermal synthesis, the product-containing zeolite containing the template is separated from the hydrothermal synthesis reaction solution. The method for separating the zeolite containing the template is not particularly limited. Usually, the product can be obtained by separation by filtration or decantation, washing with water, and drying at room temperature to 150 ° C. or lower.

Proton type (H ⁺ type) SAPO can be obtained by removing the template from the zeolite containing the template. The method for removing the template is not particularly limited. Usually contained in air or oxygen-containing inert gas, or by baking in an atmosphere of inert gas at a temperature of 400 ° C. to 700 ° C. or by extraction with an extraction solvent such as an ethanol aqueous solution or HCl-containing ether. Organic matter can be removed. Preferably, removal by baking is preferable in terms of manufacturability.

  The template may be removed before or after the transition metal is supported on the AEI type SAPO. That is, the metal may be supported on the zeolite from which the template is removed, or the template may be removed after the metal is supported on the zeolite containing the template. It is preferable to remove the template after the metal is supported on the zeolite containing the template in terms of a simple manufacturing process with few manufacturing steps.

  When a metal is supported on the AEI type SAPO, an AEI type SAPO obtained by removing the template by baking is used in a generally used ion exchange method. This is because the ion exchange AEI type SAPO is produced by ion exchange of the metal into the pores from which the template has been removed, and the AEI type SAPO containing the template cannot be ion exchanged. It is unsuitable.

  The template removal in the case of carrying the transition metal after removing the template is usually a method of firing at a temperature of usually 400 ° C. or higher and 900 ° C. or lower in an inert gas containing air or oxygen, or an inert gas atmosphere. , And various methods such as extraction with an extractant such as an ethanol aqueous solution and HCl-containing ether.

[Transition metal loading method]
To support the transition metal on the zeolite containing the template, for example, impregnating the zeolite with an aqueous solution of a transition metal salt and then firing it, or adding the transition metal raw material to the gel before hydrothermal synthesis And a method of directly hydrothermally synthesizing the transition metal-supported zeolite. In order to support the transition metal on the zeolite from which the template is removed, for example, an ion exchange method, an impregnation support method, a precipitation support method, a solid phase ion exchange method, a CVD method, a spray drying method, etc., preferably a solid phase ion exchange method , Impregnation support method, spray drying method.

[Transition metal raw materials]
The transition metal raw material supported on the AEI type SAPO is not particularly limited. Usually, transition metal sulfates, nitrates, phosphates, chlorides, bromides and other inorganic acid salts, acetates, oxalates, citrates, etc. And organic metal compounds such as organic acid salts, pentacarbonyl, and ferrocene. Of these, inorganic acid salts and organic acid salts are preferred from the viewpoint of solubility in water. In some cases, a colloidal oxide or a fine powdered oxide may be used.

As the transition metal raw material, two or more transition metal species or different compound species may be used in combination.

  As described above, the “transition metal” does not necessarily mean that it is in an elemental zero-valent state. Reference to “transition metal” includes the presence state supported in AEI-type SAPO, for example, the presence state as ionic or other species.

[How to use the transition metal-supported AEI type SAPO]
The gold transition metal-supported AEI-type SAPO can be used as a catalyst for purifying nitrogen oxides. Specifically, for example, the present transition metal-supported AEI-type SAPO can be used for purifying nitrogen oxides in exhaust gas by contacting exhaust gas containing nitrogen oxides.
The usage form of the present transition metal-supported AEI type SAPO is not particularly limited. For example, a mixture of the catalyst containing the present transition metal-supported AEI type SAPO is formed (including film formation), etc. It may be used as a nitrogen oxide purification element having a predetermined shape.

Components other than nitrogen oxides may be included in the exhaust gas, and for example, hydrocarbons, carbon monoxide, carbon dioxide, hydrogen, nitrogen, oxygen, sulfur oxides, and water may be included.
Nitrogen oxide-containing exhaust gas specifically includes various diesel engines, boilers, gas turbines, etc. that are used in diesel engines, gasoline automobiles, stationary power generation / ships / agricultural machinery / construction machinery / motorcycles / aircraft. Various exhaust gases containing nitrogen oxides can be mentioned.

  The contact condition between the catalyst and the exhaust gas when using the transition metal-supported AEI type SAPO is not particularly limited, but the space velocity of the exhaust gas is usually 100 / h or more, preferably 1000 / h or more, More preferably, it is 5000 / h or more, usually 500000 / h or less, preferably 400000 / h or less, more preferably 200000 / h or less, and the temperature is usually 100 ° C. or more, more preferably 125 ° C. or more, further preferably It is used at 150 ° C or higher, usually 1000 ° C or lower, preferably 800 ° C or lower, more preferably 600 ° C or lower, particularly preferably 500 ° C or lower.

  In addition, at the time of such exhaust gas treatment, the present transition metal-supported AEI-type SAPO can be used in the coexistence of a reducing agent, and the coexistence of the reducing agent allows efficient purification to proceed. As the reducing agent, one or more of ammonia, urea, organic amines, carbon monoxide, hydrocarbon, hydrogen and the like are used, and preferably ammonia and urea are used.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to the following examples. Evaluation methods, various measurement methods, analysis methods and the like in the following Examples and Comparative Examples are as follows.

[Evaluation of catalytic activity]
The prepared zeolite sample was press-molded, crushed, passed through a sieve, and sized to 0.6 to 1 mm. 1 ml of the sized zeolite sample was charged into an atmospheric pressure fixed bed flow type reaction tube. The zeolite layer was heated while a gas having the composition shown in Table 1 below was passed through the zeolite layer at a space velocity of SV = 200000 / h. When the outlet NO concentration becomes constant at a predetermined temperature,
NO purification rate (%) = {(inlet NO concentration) − (outlet NO concentration)} /
(Inlet NO concentration) x 100
Based on the value, the purification performance (nitrogen oxide removal activity) of the zeolite sample was evaluated.

[Submersion test]
Transition metal-supporting AEI type SAPO (3.0 g) and demineralized water (12.0 g) were mixed, sealed in a 100 ml fluororesin inner cylinder, and placed in a stainless steel autoclave. Heated in an oven at 100 ° C. for 6 hours. After cooling to room temperature, the slurry was taken out from the inner cylinder and filtered under reduced pressure. The wet cake was dried at 100 ° C. overnight to obtain a sample after the submergence test.

[Measurement method of XRD]
Equipment: DRU PHASER made by BRUKER
X-ray source: Cu-Kα ray output setting: 30 kV · 10 mA
Divergent slit: 0.2 °
Incident side solar slit: 2.5 °
Light receiving side solar slit: 2.5 °
Detector opening angle: 5.0 °
Ni filter: 2.5%
Diffraction peak position: 2θ (diffraction angle)
Measurement range: 2θ = 3-50 °
Scan speed: 0.41 ° (2θ / sec)

[Method of elemental analysis]
Apparatus: Shimadzu Corporation energy dispersive X-ray fluorescence spectrometer EDX-700
Measurement atmosphere: Vacuum collimator: 10 mm
Sample amount: 0.08 to 0.12 g

  As standard samples, calibration curves were prepared using SAPO with known Si / (Al + Si + P) molar ratio, Al / (Al + Si + P) molar ratio, and P / (Al + Si + P) molar ratio (by ICP measurement).

[Measurement method of average primary particle diameter by SEM]
Device: JSM-6010LV manufactured by JEOL Ltd.
Particle size measurement method: 50 primary particles observed by SEM were randomly extracted, their ferret diameter was measured, and the primary particle size was determined. The arithmetic average of the obtained particle diameters of the primary particles was used as the average primary particle diameter.

[Particle size distribution measurement]
Device: LA-950V2 manufactured by HORIBA
Measurement method: Laser diffraction / scattering dispersion medium: Demineralized water

[Method for measuring BET specific surface area]
A 20 mg zeolite sample was pretreated for 2 hours at 400 ° C. under vacuum suction. Thereafter, measurement was performed by the BET method using BELSORP-mini manufactured by Microtrack Bell.

[Example 1]
As shown in Table 2 below, 97.6 g of 85% H ₃ PO ₄ (manufactured by Wako Pure Chemical Industries, Ltd.) and 352.8 g of H ₂ O were added and stirred gently. 0.7 g was added and stirred for 1 hour. Thereafter, 4.6 g of fumed silica (Aerosil 200, manufactured by Nippon Aerosil Co., Ltd.) and 32.5 g of H ₂ O were added and stirred for 30 minutes to obtain a white aqueous gel.

  As a template, 59.6 g of N, N-diisopropylethylamine (DIEA) (manufactured by Wako Pure Chemical Industries, Ltd.) and 40.2 g of N-methylbutylamine (MBA) (manufactured by Santa Cruz Biotechnology) are added and mixed to form an amine. A mixed solution was obtained. This amine mixture was added dropwise to the aqueous gel with the aqueous gel being stirred. Thereafter, this aqueous gel was further stirred for 2 hours to obtain a raw material mixture (total weight 650.0 g) made of an aqueous gel having the composition (molar ratio) shown in Table 3 described later.

The raw material mixture thus obtained was charged into a 1000 ml stainless steel autoclave containing a fluororesin inner cylinder and reacted at 170 ° C. for 48 hours with stirring (hydrothermal synthesis). After the hydrothermal synthesis, the mixture was cooled and the resulting reaction solution was transferred to a beaker and allowed to stand for 12 hours. As a result, a white solid precipitated on the bottom of the beaker. The supernatant was discarded, water was added to the remaining precipitate to disperse it, and the dispersion was centrifuged (3500 rpm × 4 times) to wash and collect the solid content. The obtained white solid was dried at 100 ° C. for 12 hours to obtain a template-containing sample SAPO. Thereafter, baking was performed at 600 ° C. for 6 hours under air (water vapor content of 0.5% by volume or less), the template was removed, and an H ⁺ type sample SAPO was obtained.

  The XRD of SAPO thus obtained was measured (FIG. 1). As a result, it was AEI type SAPO. When elemental analysis was performed, the Si / (Al + Si + P) molar ratio (x), the Al / (Al + Si + P) molar ratio (y), and the P / (Al + Si + P) molar ratio (z) were x = 0.071, y = 0.514 and z = 0.414.

  About the obtained AEI type SAPO, an average primary particle diameter obtained by selecting arbitrary 50 primary particles from an SEM image (FIG. 2) taken at a magnification of 2000 times and arithmetically averaging the particle diameters. As shown in Table 4, it was 1.59 μm. The ratio of the primary particle diameter to the median diameter determined from the particle size distribution measurement was 2.84.

Cu was supported on the obtained H ⁺ type AEI type SAPO as follows to produce a catalyst. That is, 1.603 g of copper acetate monohydrate (purity 98% or more, manufactured by Kishida Chemical Co., Ltd.) was dissolved in 18.0 g of demineralized water. 9.0 g of the above SAPO was added and stirred for 5 minutes. Thereafter, filtration under reduced pressure was performed, and the obtained wet cake was dried at 120 to 160 ° C. The dried sample was baked at 550 ° C. for 3 hours under the flow of air (water vapor content of 0.5% by volume or less) to remove organic substances and obtain Cu-supported AEI type SAPO. This was used as an example catalyst. The amount of Cu supported was quantified by XRF and found to be 2.5% by weight.

  The above-described submergence test was performed on the obtained catalyst (Cu-supported AEI type SAPO), and a sample after the submergence test was obtained. The above-described catalytic activity evaluation was performed on the samples before and after the submergence test. The results are shown in FIG. The maintenance rate of the 200 ° C. NO purification rate before and after the submergence test was 86.5%.

[Comparative Example 1]
Journal of Physical Chemistry, Vol. 98, 10216 (1994) p. With reference to the method described in 10217, SAPO was produced as follows.

As shown in Table 1, 94.4 g of H ₂ O was added to 98.6 g of 85% H ₃ PO ₄ (manufactured by Wako Pure Chemical Industries, Ltd.), and the mixture was agitated lightly. And stirred for 1 hour. Thereafter, 5.4 g of fumed silica (Aerosil 200, manufactured by Nippon Aerosil Co., Ltd.) and 80.0 g of H ₂ O were added and stirred for 30 minutes to obtain a white gel.

  As a template, 93.3 g of N, N-diisopropylethylamine (DIEA) (manufactured by Wako Pure Chemical Industries, Ltd.) was added dropwise to the white gel with the gel stirred. After addition of DIEA, the obtained gel was stirred for 2 hours to obtain an aqueous gel (total weight 632.9 g) having the composition shown in Table 3.

The aqueous gel thus obtained was charged into a 1000 ml stainless steel autoclave containing a fluororesin inner cylinder and reacted at 160 ° C. for 192 hours with stirring (hydrothermal synthesis). After the hydrothermal synthesis, the mixture was cooled and the resulting reaction solution was transferred to a beaker and allowed to stand for 12 hours. As a result, a white solid precipitated on the bottom of the beaker. The supernatant was discarded, water was added to the remaining precipitate to disperse it, and the dispersion was centrifuged (3500 rpm × 4 times) to wash and collect the solid content. The obtained white solid was dried at 100 ° C. for 12 hours to obtain a template-containing sample. Thereafter, baking was performed at 600 ° C. for 6 hours under air (water vapor content of 0.5% by volume or less), the template was removed, and an H ⁺ type sample was obtained.

  The XRD of SAPO thus obtained was measured (FIG. 4). As a result, it was AEI type SAPO. Further, when elemental analysis was performed, Si / (Al + Si + P) molar ratio (x), Si / (Al + Si + P) molar ratio, Al / (Al + Si + P) molar ratio (y), and P / (Al + Si + P) molar ratio (z) were X = 0.065, y = 0.510, and z = 0.425, respectively.

  When the obtained AEI type SAPO was observed by SEM (FIG. 5), the crystal shape was uneven (columnar to flat plate shape), and the exact crystal particle diameter was not measured, but all the particles were in the long side direction. Was less than 1 μm.

In the same manner as in Example 1, Cu was supported on the obtained H ⁺ type AEI type SAPO to produce a catalyst. The amount of Cu supported was quantified by XRF and found to be 2.5% by weight.

  About the obtained Cu carrying | support AEI type SAPO, the above-mentioned immersion test was done and the sample after a immersion test was obtained. The above-described catalytic activity evaluation was performed on the samples before and after the submergence test. The results are shown in FIG. The maintenance rate of the 200 ° C. NO purification rate before and after the submergence test was 39.1%.

  Tables 2 to 4 collectively show the conditions and compositions of Example 1 and Comparative Example 1.

Claims (7)

At least selected from the group consisting of Ti, Fe, Co, Ni, Cu, Zn, Ga, Zr, Mo, W, Pt, Au, and Ce as a skeleton structure containing at least a silicon atom, a phosphorus atom, and an aluminum atom A transition metal-supported AEI type silicoaluminophosphate supporting one transition metal,
The transition metal loading of the zeolite is 0.5 wt% or more and 10.0 wt% or less,
The molar ratio x of silicon atoms to the total of silicon atoms, aluminum atoms and phosphorus atoms in the zeolite framework structure is 0.01 to 0.20,
The average primary particle diameter obtained from the SEM image is 1 μm or more and 50 μm or less,
A transition metal-supported AEI type silicoaluminophosphate, wherein the ratio of the median diameter obtained from the particle size distribution to the average primary particle diameter is 10 or less.   The transition metal-supported AEI type silicoaluminophosphate according to claim 1, wherein the transition metal contains at least Cu or Fe.   The transition metal-supported AEI type silicoaluminophosphate according to claim 1, wherein the transition metal is Cu.   The transition metal-supported AEI type silicoaluminophosphate according to any one of claims 1 to 3, wherein the amount of the transition metal supported is 1.0 wt% or more and 7.0 wt% or less.   The transition metal-supported AEI type silicoaluminophosphate according to any one of claims 1 to 4, wherein the molar ratio x of the silicon atoms is 0.03 to 0.15.   The transition metal-supported AEI type silicoaluminophosphate according to any one of claims 1 to 4, wherein a molar ratio x of the silicon atoms is 0.04 to 0.10.   A catalyst for purifying nitrogen oxides comprising the transition metal-supported AEI type silicoaluminophosphate according to any one of claims 1 to 6.

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