CHA type zeolite and preparation method thereof

Abstract

The invention relates to CHA type zeolite and a preparation method thereof. Provided are: a method for producing a CHA-type zeolite in which the heat resistance of a CHA-type zeolite is improved on the basis of a method different from conventional heat resistance improvement methods; and at least one of such CHA-type zeolites. It is preferable to provide a CHA-type zeolite characterized in that, in a 1H-MAS-NMR spectrum, the ratio of the integrated intensity of a maximum peak having a peak position at a chemical shift of 3.0-3.5 ppm to the integrated intensity of a maximum peak having a peak position at a chemical shift of 4.0-4.5 ppm is more than 0.12 and not more than 0.5, and in an IR spectrum, the ratio of the integrated intensity of the maximum peak having a peak position at a chemical shift of 4.0-4.5 ppm to the integrated intensity of the maximum peak having a peak position at a chemical shift of 4.0-4.5 ppm is more than 0.12 and not more than 0.5. The ratio of the maximum peak height of an absorption peak having a peak position at a wave number of 3630 cm <-1 > to 3650 cm <-1 > to the maximum peak height of an absorption peak having a peak position at a wave number of 3590 cm <-1 > to 3610 cm <-1 > is 0.40 to 1.0, and the molar ratio of silica to alumina is 8.0 to 50.0.

Description

[0001] This application is a divisional application of Chinese Patent Application No. 202180057259.8, filed on August 6, 2021, entitled "A CHA-type zeolite and its preparation method". Technical Field

[0002] This disclosure relates to a CHA-type zeolite. Background Technology

[0003] CHA-type zeolites such as SSZ-13 or SSZ-62 are prone to skeletal disintegration when exposed to high temperature and high humidity atmospheres. Therefore, heat-resistant CHA-type zeolites have been studied to date, and these CHA-type zeolites are capable of being used as selective catalytic reduction (SCR) catalysts for nitrogen oxides.

[0004] For example, a CHA-type zeolite (Patent Document 1) is disclosed, which has an average crystal diameter of 1.5 μm or more and a SiO2 / Al2O3 ratio of 15 or more. Its characteristic is that the SiO2 / Al2O3 ratio is 15 or more and the molar ratio of silanol groups to silicon is 1.6 × 10⁻⁶. -2 The following are CHA-type zeolites (Patent Document 2) with an average crystal diameter of 0.5 μm or more and less than 1.5 μm and a volume diameter of 3.2 or less relative to 50% of the 10% volume diameter, and CHA-type zeolites (Patent Document 3) characterized by having a Chabazite structure, containing Si and Al, having a lattice constant ≤13.74 Å, and having a crystallinity ≥140%.

[0005] Existing technical documents Patent documents Patent Document 1: US Patent Publication No. 2011 / 0251048 Patent Document 2: Japanese Patent Application Publication No. 2018-135261 Patent Document 3: Japanese Patent Application Publication No. 2017-218367 Summary of the Invention

[0006] The technical problem that the invention aims to solve Represented by Patent Documents 1 and 2, previous studies have explored improving heat resistance by controlling methods such as crystal grain size, SiO2 / Al2O3 ratio, or silanols. Furthermore, in Patent Document 3, the heat resistance of CHA-type zeolites with low SiO2 / Al2O3 ratios obtained solely from raw materials without organic structure directing agents was improved. In contrast, the present disclosure aims to provide at least one of the following: improving the heat resistance of CHA-type zeolites using a method different from existing heat resistance improvement methods; a method for manufacturing CHA-type zeolites with improved heat resistance; and CHA-type zeolites with improved heat resistance.

[0007] Means for solving technical problems In this disclosure, we focus on the state of protons at the solid acid sites of CHA-type zeolites, especially CHA-type zeolites with a SiO2 / Al2O3 ratio of 8 or higher. Furthermore, we have found that the heat resistance of CHA-type zeolites is further improved by treating them under specific conditions.

[0008] That is, the present invention is as described in the technical solutions in the claims, and the gist of this disclosure is as follows.

[0009] [1] A CHA-type zeolite, characterized in that, 1 In the 1H-MAS-NMR spectrum, the integrated intensity of the largest peak at chemical shifts of 3.0–3.5 ppm is greater than 0.12 and less than 0.5 relative to the integrated intensity of the largest peak at chemical shifts of 4.0–4.5 ppm. Furthermore, in the IR spectrum, at a wavenumber of 3630 cm⁻¹… -1 Above and 3650cm -1 The following absorption peaks have maximum peak heights relative to wavenumber 3590 cm⁻¹. -1 Above and 3610cm -1 The ratio of the maximum peak height of the following absorption peaks is greater than 0.40 and less than 1.0.

[0010] [2] According to the CHA-type zeolite described in [1] above, it is characterized in that, in the IR spectrum, at a wavenumber of 3630 cm⁻¹ -1 Above and 3650cm -1 The following absorption peaks have maximum peak heights relative to wavenumber 3590 cm⁻¹. -1 Above and 3610cm -1 The ratio of the maximum peak height of the following absorption peaks is 0.55 or higher and 1.0 or lower.

[0011] [3] According to the CHA-type zeolite described in [1] or [2] above, wherein, in the 1In H-MAS-NMR spectra, the ratio of the integrated intensity of the largest peak with a chemical shift of 3.0–3.5 ppm to the integrated intensity of the largest peak with a chemical shift of 4.0–4.5 ppm is greater than 0.13 and less than 0.5.

[0012] [4] The CHA type zeolite according to any one of [1] to [3] above, wherein the molar ratio of silicon dioxide to aluminum oxide is 8.0 or more and 50.0 or less.

[0013] [5] The CHA type zeolite according to any one of [1] to [4] above contains transition metal elements.

[0014] [6] A method for manufacturing CHA type zeolite, characterized in that it includes a step of treating a CHA type zeolite precursor containing an organic structure directing agent under a water-containing atmosphere.

[0015] [7] According to the manufacturing method described in [6] above, the organic structure directing agent is one or more selected from N,N,N-trialkyladamantane ammonium cation, N,N,N-trimethylbenzylammonium cation, N-alkyl-3-quinol cation, N,N,N-trialkylexoaminonorbornene cation and N,N,N-trialkylcyclohexylammonium cation.

[0016] [8] According to the manufacturing method described in [6] or [7] above, wherein the molar ratio of silica to alumina in the CHA-type zeolite precursor is 8.0 or more.

[0017] [9] The manufacturing method according to any one of [6] to [8] above, wherein the cationic form of the CHA-type zeolite precursor is sodium-potassium type.

[0018]

[10] The manufacturing method according to any one of [6] to [9] above, wherein the content of alkali metal element in the CHA type zeolite precursor is 0.1% by mass or more.

[0019]

[11] The manufacturing method according to any one of [6] to

[10] above, wherein the water-containing atmosphere is an air atmosphere in which the water content is 5% or more and 95% or less of the saturated water vapor content.

[0020]

[12] The manufacturing method according to any one of [6] to

[11] above, wherein the water treatment is a process of placing the CHA type zeolite precursor in a calcining furnace and then heating it to the water treatment temperature.

[0021]

[13] The manufacturing method according to any one of [6] to

[12] above, wherein the water treatment is a process of introducing the CHA type zeolite precursor into a calcining furnace that has been heated to the water treatment temperature.

[0022]

[14] The manufacturing method according to any one of [6] to

[13] above, wherein the water treatment temperature of the water treatment is 400°C or higher.

[0023]

[15] A CHA type zeolite, which is obtained by any one of the manufacturing methods described in [6] to

[14] above.

[0024]

[16] The CHA-type zeolite according to

[15] above is characterized in that, in the IR spectrum, at a wavenumber of 3630 cm⁻¹ -1 Above and 3650cm -1 The following absorption peaks have maximum peak heights relative to wavenumber 3590 cm⁻¹. -1 Above and 3610cm -1 The ratio of the maximum peak height of the following absorption peaks is 0.55 or higher and 1.0 or lower.

[0025]

[17] A nitrogen oxide reduction catalyst, characterized in that it comprises any one of the above [1] to [5],

[15] and

[16] CHA type zeolite.

[0026]

[18] A method for reducing nitrogen oxides, characterized in that the CHA type zeolite described in any one of [1] to [5],

[15] and

[16] above is used.

[0027] Invention Effects According to this disclosure, it is possible to provide a CHA-type zeolite with high heat resistance compared to existing CHA-type zeolites, and a catalyst containing the CHA-type zeolite, a nitrogen oxide reduction catalyst, and a nitrogen oxide reduction catalyst based on selective catalytic reduction. Detailed Implementation

[0028] Hereinafter, an example of an embodiment of the CHA-type zeolite of the present invention will be described. It should be noted that the terminology used in this embodiment is as follows.

[0029] "Aluminosilicate" is a composite oxide having a repeating network structure consisting of aluminum (Al) and silicon (Si) via oxygen (O). In the powder X-ray diffraction (XRD) pattern of aluminosilicates, substances with crystalline XRD peaks are called "crystalline aluminosilicates," and substances without crystalline XRD peaks are called "amorphous aluminosilicates."

[0030] In this embodiment, the XRD pattern is measured using CuKα rays as the radiation source. The following conditions can be cited as the conditions for its measurement.

[0031] X-ray source: CuKα rays (λ = 1.5406 Å) Measurement mode: Step scan Scanning speed: 4.0° per minute Measurement range: 2θ = 3.0°~40.0° The following conditions can be cited as preferred criteria.

[0032] Accelerating current and voltage: 40mA·40kV X-ray source: CuKα rays (λ = 1.5405 Å) Measurement mode: Step scan Scanning conditions: 40° / minute Measurement time: 3 seconds Measurement range: 2θ = 3° to 43° Longitudinal diverging slit: 10mm Diverging / Incident Slit: 1° Light-receiving slit: open Light-receiving Soler slit: 5° Detector: Semiconductor detector (D / teX Ultra) Filter: Ni filter Crystalline XRD peaks are specific 2θ peaks detected in the analysis of XRD patterns using general analysis software (such as SmartLab Studio II, manufactured by Rigaku). Examples of crystalline XRD peaks are XRD peaks with a half-width of 2θ = 0.50° or less.

[0033] "Zeolite" refers to a compound having an ordered structure of framework atoms (hereinafter also referred to as "T atoms") formed by oxygen (O), and the T atoms comprising at least one of metal atoms and / or half-metal atoms. Examples of half-metal atoms include one or more selected from boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), and tellurium (Te).

[0034] "Zeolite analogues" refer to compounds that have an ordered structure formed by T atoms through oxygen, and that contain at least atoms other than metals and half-metals in the T atoms. Examples of zeolite analogues include complex phosphorus compounds such as aluminum phosphate (AlPO) and silica aluminum phosphate (SAPO), which contain phosphorus (P) as T atoms.

[0035] The "ordered structure" (hereinafter also referred to as "zeolite structure") in zeolites or zeolite-like substances refers to the framework structure as defined by the structure code (hereinafter also simply "structure code") prescribed by the Structure Commission of the International Zeolite Association. For example, the CHA structure is the framework structure defined by the structure code "CHA". Zeolite structures can be identified by comparing them with the XRD patterns of the various structures described in the Collection of simulated XRD powder patterns for zeolites, Fifth revised edition, p. 483 (2007) (hereinafter also referred to as "reference patterns"). Regarding zeolite structures, framework structure, crystal structure, or crystalline phase are used synonymously.

[0036] In this embodiment, “CHA-type zeolite” and other “~-type zeolite” mean a zeolite with the structure code, and preferably means a crystalline aluminosilicate with the structure code.

[0037] "IR spectrum" refers to the IR spectrum of CHA-type zeolite, which does not contain organic structure directing agents and has a protonated cationic form, measured under the following conditions.

[0038] Measurement method: Diffuse reflectance method Wavenumber range for measurement: 400–4000 cm⁻¹ -1 Resolution: 4cm -1 Points earned: 128 times Reference: KBr.

[0039] IR spectra can be measured using a general FT-IR device (e.g., Varian660-IR, manufactured by Agilent Technologies). The obtained IR spectra can be converted to absorbance values, baseline corrected, and analyzed using a common spectral data analysis program (e.g., GRAMS / AI, manufactured by Thermo Fisher Scientific).

[0040] “ 1 "H-MAS-NMR spectroscopy" refers to the spectroscopy of CHA-type zeolites that do not contain organic structure-directing agents and are cationic proton-type zeolites measured under the following conditions. 1 H-MAS-NMR spectrum.

[0041] Resonant frequency: 400.0MHz Pulse width: π / 2 Measurement waiting time: 10 seconds Points earned: 32 times Rotation frequency: 15kHz Chemical shift reference: TMS.

[0042] 1 H-MAS-NMR spectra can be measured using general NMR measuring devices (such as VNMRS-400, manufactured by Varian). The obtained NMR spectra can be baseline corrected and analyzed using common spectral data analysis programs (such as GRAMS / AI, manufactured by Thermo Fisher Scientific).

[0043] "Average grain size" is the average grain size based on SEM observations. It is the average value of the size of primary particles (primary grain size) measured from images observed by a scanning electron microscope (SEM). More specifically, it refers to the average grain size obtained by measuring the length of one side of the rhomboid facet of CHA-type zeolite present in the field of view of an SEM image observed at any magnification (e.g., 5000 to 10000x) that can observe more than 150, preferably 200 ± 50 primary grains.

[0044] Hereinafter, an example of an embodiment of the method for manufacturing CHA-type zeolite of this disclosure will be shown and described.

[0045] The manufacturing method of this embodiment is a method for manufacturing CHA-type zeolite, characterized by a step of treating a CHA-type zeolite precursor containing an organic structure directing agent under an aqueous atmosphere. By treating the CHA-type zeolite containing the organic structure directing agent (hereinafter also referred to as "SDA") under an aqueous atmosphere, SDA removal and heat resistance improvement of the CHA-type zeolite can be achieved simultaneously. The CHA-type zeolite obtained by the manufacturing method of this embodiment can serve as a precursor for nitrogen oxide reduction catalysts exhibiting higher NOx reduction rates.

[0046] <Precursor CHA> The CHA-type zeolite precursor (hereinafter, also called "precursor CHA") supplied for the process of treating a CHA-type zeolite precursor containing an organic structure directing agent under an aqueous atmosphere (hereinafter also referred to as the "aqueous treatment process") is a synthetically produced CHA-type zeolite (synthetic CHA-type zeolite), which is any CHA-type zeolite containing SDA. The precursor CHA is preferably a zeolite whose framework element does not contain phosphorus.

[0047] The SDA contained in the precursor CHA can be any cation that functions as a directed CHA-type zeolite (more specifically, a CHA structure, hereinafter the same). Examples of cations functioning as directed CHA-type zeolites include one or more selected from the group consisting of N,N,N-trialkyladamantane ammonium cation, N,N,N-trimethylbenzylammonium cation, N-alkyl-3-quinol cation, N,N,N-trialkylexoaminonorbornene cation, and N,N,N-trialkylcyclohexylammonium cation, preferably N,N,N-trialkyladamantane ammonium cation (hereinafter also referred to as "TAAd"). + N,N,N-trimethylbenzylammonium cation (hereinafter also referred to as "TMBA") + ), and N,N,N-trialkylcyclohexylammonium cation (hereinafter also referred to as "TACH"), and N,N,N-trialkylcyclohexylammonium cation (hereinafter also referred to as "TACH"). + More than one of the group consisting of “”, preferably TAAd + and TACH + At least one of them, particularly preferably TAAd + and TACH + .

[0048] As the preferred TAAd + Examples include N,N,N-trimethyladamantane ammonium cation (hereinafter also referred to as "TMAd"). + Additionally, TACH is the preferred option. + Examples include N,N,N-dimethylethylcyclohexylammonium cation (hereinafter also referred to as "CDMEA"). + ") and N,N,N-methyldiethylcyclohexylammonium cation (hereinafter, also known as "MDECH") ... + At least one of the following can be cited: CDMEA + .

[0049] Precursor CHA preferably contains at least CDMEA + More preferably, it contains TMAd + and CDMEA + Additionally, the precursor CHA may also contain TMAd. + and CDMEA + At least one of them.

[0050] The precursor CHA contains SDA; that is, CHA-type zeolites containing SDA can be identified by XRD patterns. The precursor CHA preferably has XRD peaks in its XRD pattern, at least within the interplanar spacing d shown in the table below.

[0051] [Table 1]

[0052] *Relative intensity is a relative value of the intensity with respect to the interplanar spacing d = 4.22–4.32 Å. In addition to the XRD peaks mentioned above, the precursor CHA may also contain the following XRD peaks.

[0053] [Table 2]

[0054] *Relative intensity is a relative value of the intensity with respect to the interplanar spacing d = 4.22–4.32 Å. It should be noted that the precursor CHA may also contain any XRD peak whose intensity (hereinafter also referred to as "relative intensity") relative to the XRD peak intensity at the interplanar spacing d = 4.22 to 4.32 Å is less than 5.

[0055] The molar ratio of SDA to alumina in the precursor CHA (hereinafter also referred to as "SDA content") can be greater than 0 and is 0.1 or more, 0.3 or more, 0.6 or more, 0.7 or more, or 0.8 or more, while being less than 1.0.

[0056] The molar ratio of silicon dioxide to aluminum oxide in the precursor CHA (hereinafter also referred to as "SiO2 / Al2O3 ratio") is preferably 8.0 or more, 10.0 or more, or 12.0 or more, and is 30.0 or less, 25.0 or less, 20.0 or less, 19.5 or less, or 15.0 or less.

[0057] The SDA content in this embodiment is calculated using the following formula.

[0058] SDA content = 1 - {(M1 + 1 / n × M2) / Al} [mol / mol] In this formula, M1 is a monovalent metal cation, and M2 is an n-valent metal cation. For example, when the precursor CHA contains sodium, potassium, and magnesium, the SDA content can be calculated from 1 - {(Na+K+1 / 2×Mg) / Al} [mol / mol].

[0059] The average grain size of the precursor CHA is 0.3 μm or more or 0.4 μm or more, and preferably 2.0 μm or less, 1.5 μm or less, 1.2 μm or less, 1.0 μm or less or 0.8 μm or less.

[0060] The cationic forms of the precursor CHA can be selected from the sodium (Na) form, potassium (K) form, sodium-potassium (Na-K) form, and proton (H) form. + Type ) and ammonium type (NH4) +The zeolite contains one or more of the following types (types), and the alkali metal exchange rate (the ratio of alkali metal cations [mol] to Al [mol]; [mol%]) is 20% or more or 30% or more, preferably a cationic type of 100% or less or 70% or less. Examples of such cationic types include one or more of the following types: sodium type, potassium type, and sodium-potassium type; at least one of the following sodium type and sodium-potassium type; or sodium-potassium type. By performing aqueous treatment in a state containing alkali metal, the state change of the protons of the oxygen atoms forming the zeolite framework is determined to a degree that can be confirmed by measurement such as IR. As a result, the heat resistance of CHA-type zeolite is considered to be improved.

[0061] The precursor CHA preferably has a molar ratio of alkali metal to aluminum of 0.05 or more or 0.1 or more, and is 1.0 or less, 0.8 or less or 0.5 or less.

[0062] Since heat resistance is more easily improved through water treatment, the precursor CHA preferably contains alkali metals. The content of alkali metal elements (e.g., sodium and potassium) can be 0.1% by mass or more, greater than 0.5% by mass, 1.0% by mass or more, 1.5% by mass or more, or 2.0% by mass or more, while being less than 10.0% by mass, less than 8.0% by mass, or less than 5.0% by mass. The alkali metal content is the total mass percentage (mass %) of the alkali metals, silicon, and aluminum in the precursor CHA after conversion to oxides, and can be calculated by {M2O[g] / (SiO2+Al2O3+M2O)[g]}×100.

[0063] The precursor CHA is preferably free of phosphorus (P) and fluorine (F), for example, the content of phosphorus and fluorine is 500 ppm or less by mass or 100 ppm or less by mass, and preferably below the detection limit of composition analysis such as ICP determination (e.g., 100 ppm or less by mass).

[0064] <Preparation method of precursor CHA> The precursor CHA can be any CHA-type zeolite obtained by a manufacturing method having a step of crystallizing a composition containing SDA. An example of a manufacturing method for the precursor CHA is a manufacturing method having a step of crystallizing a composition (hereinafter also referred to as the "raw material composition") containing a silica source, an alumina source, an alkali source, an organic structure directing agent, and water (hereinafter also referred to as the "crystallization step").

[0065] The silica source is a compound containing silicon (Si), and may be selected from one or more of the group consisting of colloidal silica, precipitated silica, amorphous silica, sodium silicate, tetraethoxysilane and amorphous aluminum silicate, preferably amorphous aluminum silicate.

[0066] The alumina source is a compound containing aluminum (Al), and may be selected from one or more of the group consisting of aluminum sulfate, sodium aluminate, aluminum hydroxide, aluminum chloride and amorphous aluminum silicates, preferably at least one of aluminum hydroxide and amorphous aluminum silicates, and more preferably amorphous aluminum silicates.

[0067] An alkali source is a compound containing an alkali metal element. Examples include compounds containing one or more elements selected from the group consisting of sodium, potassium, rubidium, and cesium; compounds containing one or more elements selected from the group consisting of sodium, potassium, and cesium; compounds containing at least one element selected from sodium and potassium; or compounds containing sodium. Examples of alkali sources include one or more elements selected from the group consisting of hydroxides, fluorides, bromides, iodides, sulfates, nitrates, and carbonates containing the aforementioned alkali metal elements; one or more elements selected from the group consisting of hydroxides, bromides, and iodides; or hydroxides (hereinafter, alkali sources containing sodium are referred to as "sodium sources," and alkali sources containing potassium are referred to as "potassium sources," etc.). The raw material composition particularly preferably contains sodium and potassium sources. In addition, when starting materials such as silica sources contain alkali metal elements, these starting materials are also considered as alkali sources.

[0068] In addition to pure water and ion-exchanged water, water that is used as a starting material, including structural water, hydrated water, and water used as a solvent, is also considered as water in the raw material composition.

[0069] Organic structure directing agent (SDA) is a cation that functions to direct CHA-type zeolite (CHA structure), and is the aforementioned cation. The raw material composition may include at least one of the following: a salt as SDA and a compound (hereinafter also referred to as "SDA source"). The SDA source is selected from one or more of the group consisting of hydroxides, bromides, iodides, carbonates, methyl carbonates, and sulfates containing the aforementioned SDA, and preferably from one or more of the group consisting of hydroxides, bromides, and iodides.

[0070] Preferred compositions for the raw material composition include the following molar compositions. It should be noted that in the following molar compositions, SDA is an organic structure-directing agent, and M is an alkali metal element. SDA stands for TMAd. + In this case, set the SDA / SiO2 ratio to "TMAd". + The ratio of / SiO2 can be calculated. Additionally, in TMAd... + and CDMEA + In this case, the SDA / SiO2 ratio is set to "(TMAd + +CDMEA +The M / SiO2 ratio can be set to "Na / SiO2 ratio". When M is sodium, the M / SiO2 ratio can be set to "Na / SiO2 ratio". In addition, when M is sodium and potassium, the M / SiO2 ratio can be set to "(Na+K) / SiO2 ratio".

[0071] The SiO2 / Al2O3 ratio is 5.0 or higher, or 10.0 or higher, and below 20.0 or below 15.0. SDA / SiO2 ratio = 0.06 or higher or 0.07 or higher, and 0.12 or lower or 0.10 or lower. The M / SiO2 ratio is ≥0.10 or ≥0.15, and ≤0.30 or ≤0.25. The H2O / SiO2 ratio is 8.0 or higher, or 10.0 or higher, and below 25.0 or below 20.0. The raw material composition may contain seed crystals. Seed crystals are zeolites that promote the crystallization of CHA-type zeolites, preferably CHA-type zeolites. The content of seed crystals is calculated as the mass of silicon (Si) containing seed crystals converted to silicon dioxide (SiO2) relative to the mass of silicon (Si) contained in the raw material composition (excluding seed crystals), and examples include 0% by mass or more, 1% by mass or more, and 10% by mass or less, or 5% by mass or less.

[0072] Through a crystallization process, the raw material composition is crystallized to obtain CHA-type zeolite (precursor CHA) containing SDA. Crystallization can be exemplified by filling the raw material composition into a sealed container and subjecting it to hydrothermal treatment. The crystallization conditions are arbitrary, and the following conditions can be exemplified.

[0073] Crystallization temperature: above 100℃ or above 140℃ and below 200℃ or below 170℃ Crystallization time: 1 hour or more, or 10 hours or more but less than 100 hours or less than 80 hours Crystallization state: at least one of stirring state and standing state, preferably stirring state. Crystallization pressure: self-generated pressure After the crystallization process, the precursor CHA is recovered through solid-liquid separation. It is then washed and treated to remove moisture and impurities (e.g., heat treatment such as drying, for example, heat treatment at less than 400°C, or further, heat treatment at 300°C or higher but less than 400°C). In other words, the precursor CHA only needs to be CHA-type zeolite in a state where it has not undergone heat treatment at 400°C or higher after crystallization.

[0074] <Water Treatment> In the aqueous treatment process, the precursor CHA is treated in an aqueous atmosphere (hereinafter also referred to as "aqueous treatment"). This removes SDA from the precursor CHA and improves its heat resistance. One reason for the improved heat resistance of CHA-type zeolite through aqueous treatment of the precursor CHA is that the CHA-type zeolite obtained by crystallizing the raw material composition containing SDA is subjected to heat treatment in an atmosphere with sufficient moisture. Specifically, it is believed that SDA exists in a state where it can achieve valence compensation with the specific aluminum constituting the CHA structure. Therefore, an interaction between SDA and moisture in the atmosphere occurs at the sites where SDA is present, and heat treatment is performed under a moderate load. Thus, it is believed that although heat treatment is performed in an aqueous atmosphere, the heat load on the overall zeolite framework is suppressed, thereby improving heat resistance.

[0075] A water-containing atmosphere is an atmosphere (especially an air atmosphere) with a water content (hereinafter also referred to as "moisture content") of 5% or more, 10% or more, 30% or more, or 50% or more relative to the saturated water vapor content, and at the same time, an atmosphere (especially an air atmosphere) with a water content of 100% or less, 90% or less, or 70% or less. Since CHA-type zeolites treated with water content tend to have a high solid acid content, the water-containing atmosphere is an air atmosphere with a moisture content of 15% or more and 90% or less, preferably an air atmosphere with a moisture content of 45% or more and 80% or less. The moisture content can be adjusted by methods such as circulating a mixture of air and water vapor, filling the reaction vessel with water and heating it, or using a water-containing precursor CHA.

[0076] The moisture treatment is preferably carried out under conditions where air circulates to achieve the aforementioned moisture content, and can be carried out using one or more known firing furnaces selected from the group consisting of muffle furnaces, tubular furnaces, and kilns.

[0077] The water-containing treatment temperature can be any temperature above 400°C, above 500°C, or above 550°C, and below 800°C, below 650°C, or below 600°C. In order to effectively remove SDA while suppressing the disintegration of the CHA structure, the water-containing treatment temperature is particularly preferably above 500°C and below 700°C.

[0078] The water treatment time varies depending on the water treatment temperature, the amount of CHA precursor supplied for water treatment, etc., but any time excluding SDA is acceptable, and examples can be any time between 10 minutes or more, 1 hour or more, and 24 hours or less, or 5 hours or less. It should be noted that the water treatment time is the treatment time at the water treatment temperature (maximum reached temperature).

[0079] Moisture treatment simply involves either introducing the precursor CHA into a firing furnace and heating it to the moisture treatment temperature, or placing the precursor CHA in a firing furnace and then heating it to the moisture treatment temperature. The rate at which the firing furnace is heated to the moisture treatment temperature and the rate at which it is cooled after moisture treatment are arbitrary. For example, heating and cooling rates can be 1°C / min or higher, or 2°C / min or higher, and less than 10°C / min or less than 5°C / min. The heating and cooling rates can also be different.

[0080] <Post-processing steps> The manufacturing method of this embodiment may include, as needed, at least one of the following steps after the water treatment step: an ion exchange step and a metal-containing step.

[0081] In the ion exchange process, CHA-type zeolite undergoes ion exchange to form any cationic form. Examples of cationic forms include sodium form (Na form) and ammonium form (NH4+). + Type 1) and proton type (H) + At least one of the following types (specifically, proton type): ion exchange. Ion exchange can be performed using any ion exchange method. For example, when the cationic type is set to NH4... + In the case of the cationic type, a method for mixing and stirring CHA-type zeolite in an ammonium chloride aqueous solution can be exemplified, where the cationic type is set as H + In the case of the cationic form NH4, it is possible to exemplify this. + Methods for calcining CHA-type zeolites, or methods for mixing and stirring in hydrochloric acid aqueous solution.

[0082] The metal-containing process involves contacting the CHA-type zeolite with a metal compound. This allows the CHA-type zeolite to contain any metal element that functions as an active metal. Examples of metal elements include catalyst metal elements, specifically transition metal elements, and are further selected from at least one element selected from the group consisting of platinum, palladium, rhodium, iron, copper, cobalt, manganese, and indium; at least one element selected from the group consisting of cobalt, nickel, iron, and copper; at least one element selected from iron and copper; or copper. The method of containing the metal is arbitrary, but a method of supporting the metal element in the CHA-type zeolite is preferred. Specifically, examples include at least one element selected from the group consisting of ion exchange, impregnation support, evaporation-drying, precipitation support, and physical mixing, with at least one ion exchange and impregnation support methods being preferred, and impregnation support methods being more preferred.

[0083] The metal compound is arbitrary and may be one or more selected from the group consisting of nitrates, sulfates, acetates, chlorides, complex salts and oxides of metals, preferably one or more selected from the group consisting of nitrates, sulfates and acetates.

[0084] After contacting CHA-type zeolite with a metal compound, it can be calcined to produce metal-containing CHA-type zeolite (hereinafter also referred to as "metal-containing CHA-type zeolite") as needed. Examples of calcination conditions include atmospheric conditions, temperatures above 500°C and below 700°C, and firing times of 0.5 hours and below 5 hours. It should be noted that "atmosphere" refers to an air atmosphere where moisture content is not controlled, and examples include air with a moisture content greater than 0% by volume and less than 3% by volume.

[0085] <CHA type zeolite> Hereinafter, an example of an embodiment will be shown while the CHA-type zeolite of the present invention will be described.

[0086] The CHA-type zeolite of this embodiment is characterized in that... 1 In the H-MAS-NMR spectrum, the integrated intensity of the largest peak at chemical shifts of 3.0–3.5 ppm is greater than 0.12 and less than 0.5 relative to the integrated intensity of the largest peak at chemical shifts of 4.0–4.5 ppm. Furthermore, in the IR spectrum, at a wavenumber of 3630 cm⁻¹… -1 Above and 3650cm -1 The following absorption peaks with peak positions have maximum peak heights relative to wavenumber 3590 cm⁻¹. -1 Above and 3610cm -1 The ratio of the maximum peak height of the following absorption peaks is greater than 0.40 and less than 1.0.

[0087] The CHA-type zeolite of this embodiment has a wavenumber of 3630 cm⁻¹ in the IR spectrum. -1 Above and 3650cm -1 The following are the maximum peak heights of absorption peaks with peak positions (hereinafter also referred to as "IR"). P2 (relative to wavenumber 3590cm) -1 Above and 3610cm -1 The following are the maximum peak heights of absorption peaks with peak positions (hereinafter also referred to as "IR"). P1 The ratio of (hereinafter, also known as "IR") to () P2 / IR P1 The ratio (or IR ratio) is 0.4 or higher and 1.0 or lower, preferably 0.45 or higher and 1.0 or lower, and more preferably 0.55 or higher and 1.0 or lower.

[0088] The CHA structure contains oxygen atoms at different atomic positions (i.e., non-equivalent oxygen atoms) in its zeolite structure. The oxygen atoms are: oxygen atoms that form oxygen 4-membered ring structure and oxygen 8-membered ring structure and are present at the connection positions of the two oxygen 6-membered rings that form oxygen double 6-membered rings (hereinafter also referred to as "O(1)"); oxygen atoms that form oxygen 4-membered ring and oxygen 8-membered ring and are present at the connection positions of the two oxygen double 6-membered rings (hereinafter also referred to as "O(2)"); oxygen atoms that form 6-membered rings and also form oxygen 4-membered rings and oxygen 8-membered rings (hereinafter also referred to as "O(3)"); and oxygen atoms that form oxygen 6-membered rings and form oxygen 4-membered rings but do not form oxygen 8-membered rings (hereinafter also referred to as "O(4)").

[0089] IR is considered P1 and IR P2 The peak heights are respectively the IR peaks of the protons via O(1) and O(2). By satisfying the above-mentioned IR ratio, the framework structure is difficult to disintegrate even when exposed to high temperature and high humidity. The IR ratio is preferably 0.58 or higher or 0.60 or higher, and at the same time, it is 0.80 or lower or 0.70 or lower.

[0090] The CHA-type zeolite in this embodiment is 1 In H-MAS-NMR spectra, the integrated intensity of the maximum peak at chemical shifts of 3.0–3.5 ppm (hereinafter also referred to as "NMR") is the value of the peak at that position. P2 The integral intensity of the maximum peak with a chemical shift of 4.0–4.5 ppm (hereinafter also referred to as "NMR") relative to the maximum peak with a chemical shift of 4.0–4.5 ppm. P1 The ratio of (hereinafter, also known as "NMR") to () P2 / NMR P1 The NMR ratio is greater than 0.12 and less than 0.5, preferably greater than 0.13 and less than 0.5. More preferably, the NMR ratio is greater than 0.13, greater than 0.14, or greater than 0.15, and less than 0.5, less than 0.3, or less than 0.2. P1 and NMR P2 The integrated intensity of the peaks attributed to protons bound to O(1) and O(3), respectively, and the NMR... P2 The heat resistance of CHA-type zeolites is easily increased by satisfying the above NMR ratio, which is due to the integrated intensity of the peak of the protons that are bound to O(2).

[0091] In this embodiment, the preferred molar ratio of silica to alumina (hereinafter also referred to as "SiO2 / Al2O3 ratio") of the CHA-type zeolite is 5.0 or more, 8.0 or more, or 12.0 or more, and is 50.0 or less, less than 30.0, 25.0 or less, 20.0 or less, or 15.0 or less.

[0092] The average grain size of the CHA-type zeolite in this embodiment is preferably 0.3 μm or more, 0.4 μm or more, or 0.45 μm or more, and is 2.0 μm or less, 1.5 μm or less, 1.2 μm or less, 1.0 μm or less, 0.8 μm or less, or 0.6 μm or less. Since workability (slurry workability) is easily improved without compromising crystallinity, the average grain size is preferably less than 2.0 μm, 1.8 μm or less, or 1.5 μm or less.

[0093] The cationic type of the CHA-type zeolite in this embodiment is arbitrary, and examples can be selected from sodium-potassium type (Na-K type) and proton type (H type). + Type ) and ammonium type (NH4) + One or more species from the group consisting of sodium type (Na type) and proton type (H type) + Type ) and ammonium type (NH4) + It consists of one or more of the following groups: proton type and ammonium type, or at least one of the following proton types. In addition, the cationic type can also be sodium-potassium type.

[0094] The CHA-type zeolite of this embodiment preferably contains a catalyst metal element, and more preferably a transition metal element. The transition metal element is one or more elements selected from the group consisting of Groups 8, 9, 10 and 11 of the periodic table, and further selected from one or more elements selected from the group consisting of platinum (Pt), palladium (Pd), rhodium (Rh), iron (Fe), copper (Cu), cobalt (Co), manganese (Mn) and indium (In), and one or more elements selected from the group consisting of cobalt (Co), nickel (Ni), iron (Fe) and copper (Cu), and at least one of iron and copper, or copper.

[0095] The form in which the transition metal element is contained is arbitrary, as long as it is present either inside or outside the zeolite framework. Examples include at least one of the following states: pores and ion exchange points, where the transition metal element is supported outside the zeolite framework. Preferably, the transition metal element is contained outside the zeolite framework, and more preferably, it is supported within the zeolite.

[0096] The transition metal content of the CHA-type zeolite in this embodiment is 1.0% by mass or more, 1.5% by mass or more, or 2.0% by mass or more, and is 5.0% by mass or less, 4.5% by mass or less, or 4.0% by mass or less.

[0097] Example Hereinafter, this embodiment will be described based on the examples and comparative examples. However, this embodiment is not limited to the following examples.

[0098] (Identification of crystals) The XRD analysis of the samples was performed using a standard powder X-ray diffractometer (Ultima IV, manufactured by Rigaku). The measurement conditions are as follows.

[0099] Accelerating current and voltage: 40mA·40kV X-ray source: CuKα rays (λ = 1.5405 Å) Measurement mode: Step scan Scanning conditions: 40° / minute Measurement time: 3 seconds Measurement range: 2θ = 3° to 43° Longitudinal diverging slit: 10mm Diverging / Incident Slit: 1° Light-receiving slit: open Light-receiving Soler slit: 5° Detector: Semiconductor detector (D / teX Ultra) Filter: Ni filter The obtained XRD pattern is compared with the reference pattern to identify the crystal structure of the sample.

[0100] (SiO2 / Al2O3 ratio) The composition of the sample was determined by fluorescence X-ray diffraction. The SiO2 / Al2O3 ratio was calculated using a calibration curve based on the X-ray intensity ratio of Si to Al.

[0101] (IR spectrum) The IR spectra of the pretreated samples were measured under the following conditions.

[0102] <Preprocessing> Sample: CHA type zeolite (cationic type: H) + Type, SDA: does not contain) Processing atmosphere: Vacuum Processing temperature: 400℃ Processing time: 2 hours It is used as a pretreatment by processing at the processing temperature.

[0103] <IR Measurement> For the pretreated samples, the IR spectra were measured using a standard FT-IR apparatus (Varian 660-IR, manufactured by Agilent Technologies) while maintaining the pretreatment temperature. The measurement conditions are shown below.

[0104] Measurement method: Diffuse reflectance method Wavenumber range for measurement: 400–4000 cm⁻¹ -1 Resolution: 4cm -1 Points earned: 128 times Reference: KBr The obtained IR spectra are converted to absorbance values, baseline corrected, and analyzed using spectral data analysis programs (e.g., GRAMS / AI, Thermo Fisher Scientific).

[0105] ( 1 H-MAS-NMR spectrum) The pretreated samples were measured under the following conditions. 1 H-MAS-NMR spectrum.

[0106] <Preprocessing> Sample: CHA type zeolite (cationic type: H) + Type, SDA: does not contain) Processing atmosphere: Vacuum Processing temperature: 400℃ Processing time: 5 hours After treatment at the treatment temperature, nitrogen gas is introduced, and the sample is cooled to room temperature under a nitrogen atmosphere, which serves as a pretreatment.

[0107] <NMR Measurement> For the pretreated samples, NMR measurements were performed using a standard NMR apparatus (apparatus name: VNMRS-400, manufactured by Varian). 1 H-MAS-NMR spectra. Measurement conditions are shown below.

[0108] Resonant frequency: 400.0MHz Pulse width: π / 2 Measurement waiting time: 10 seconds Points earned: 32 times Rotation frequency: 15kHz Chemical shift reference: TMS The obtained NMR spectra were baseline corrected and analyzed using a spectral data analysis program (e.g., GRAMS / AI, Thermo Fisher Scientific).

[0109] (Average crystal grain size) The average grain size is determined by measuring the length of one side of the rhombus of 150 CHA-type zeolite primary particles identified in the field of view of a SEM image observed at 10,000x magnification using a scanning electron microscope (device name: JSM-IT200, manufactured by JEOL Ltd.). The average grain size is then taken as the average grain size.

[0110] (50% of volume diameter) A slurry was prepared by mixing 1g of powder sample with 99g of pure water, and this slurry was used as the test sample. The slurry was treated with an ultrasonic homogenizer for 2 minutes to disperse the powder sample. The volume diameter of the treated slurry was determined by laser diffraction scattering, thereby determining the 50% volume diameter.

[0111] Example 1 A 25% by mass aqueous solution of N,N,N-trimethyladamantane ammonium hydroxide (hereinafter also referred to as "TMADAOH"), a 49% by mass aqueous solution of N,N,N-dimethylethylcyclohexylammonium bromide (hereinafter also referred to as "CDMEABr"), pure water, a 48% by mass aqueous solution of sodium hydroxide, a 48% by mass aqueous solution of potassium hydroxide, and amorphous aluminosilicate were mixed to obtain a raw material composition having the following composition.

[0112] SiO2 / Al2O3 = 13.0 (TMAdA + +CDMEA + ) / SiO2=0.08 TMAdA + / SiO2=0.01 CDMEA + / SiO2=0.07 (Na+K) / SiO2=0.20 Na / SiO2 = 0.12 K / SiO2 = 0.08 H2O / SiO2 = 15 OH / SiO2 = 0.21 After mixing 1.0% by mass of seed crystals into the raw material composition, the raw material composition was sealed in a stainless steel autoclave and crystallized at 150°C for 48 hours with stirring at 55 rpm. The obtained crystals were subjected to solid-liquid separation, washed with sufficient pure water, and dried to remove moisture and impurities, serving as the precursor CHA in this embodiment. The precursor CHA contains a single phase of CHA-type zeolite, with a cationic form of sodium-potassium, SiO2 / Al2O3 = 14.0, (Na+K) / Al = 0.56 (4.7% by mass), and an average grain size of 0.49 μm. In addition, the precursor CHA contains TMAda as SDA. + and CDMEA + Its SDA content is 0.44. The XRD peaks with a relative intensity of 5 or higher in the precursor CHA are shown in the table below.

[0113] [Table 3]

[0114] *Relative strength is the relative value of the strength relative to the interplanar spacing d = 4.27. The precursor CHA was heated to 550°C at a heating rate of 3°C / min in an atmosphere in which a mixture of water vapor and dry air (0% moisture content by volume) was circulated, followed by a water treatment at 550°C for 2 hours to produce the CHA-type zeolite of this embodiment. The CHA-type zeolite of this embodiment comprises a single phase of CHA-type zeolite, with a sodium-potassium cationic form, a SiO2 / Al2O3 ratio of 13.9, and an average grain size of 0.49 μm.

[0115] The CHA-type zeolite of this embodiment was treated with a 2 mol / L hydrochloric acid aqueous solution and then subjected to ion exchange. After drying overnight at 110°C in atmospheric conditions, the cationic form was converted to the protonated form. The ion-exchanged CHA-type zeolite was equivalent to IR... P1 3599cm -1 The intensity of the peak at the position of the peak and the IR P2 3638cm -1 The intensity of the peak at the specified position is [value missing], with an IR ratio of 0.62. Additionally, NMR [value missing]. P1 and NMR P2 These are equivalent to the integrated intensities of the peak at 4.2 ppm and the peak at 3.2 ppm, respectively, with an NMR ratio of 0.15.

[0116] Example 2 The precursor CHA was subjected to a water-containing treatment in an atmosphere in which a mixed gas (air with a moisture content of 17% by volume) of dry air mixed with water vapor was circulated. Otherwise, the CHA-type zeolite of this embodiment was obtained by the same method as in Example 1. The CHA-type zeolite of this embodiment contains a single phase of CHA-type zeolite, with a cationic form of sodium-potassium type, a SiO2 / Al2O3 ratio of 13.9, and an average grain size of 0.49 μm.

[0117] In this embodiment, the CHA-type zeolite was converted from cationic to proton-type using the same method as in Example 1, resulting in a CHA-type zeolite with a proton-type cationic configuration. The IR ratio of the proton-type CHA-type zeolite was 0.45, and the NMR ratio was 0.17.

[0118] Example 3 The precursor CHA was subjected to a water-containing treatment in an atmosphere in which a mixed gas (air with a moisture content of 89% by volume) of dry air mixed with water vapor was circulated, and the water-containing treatment temperature was set to 600°C. Otherwise, the CHA-type zeolite of this embodiment was obtained by the same method as in Example 1. The CHA-type zeolite of this embodiment contains a single phase of CHA-type zeolite, the cationic type is sodium-potassium type, SiO2 / Al2O3 = 13.9, and the average grain size is 0.49 μm.

[0119] In this embodiment, the CHA-type zeolite was modified by converting the cationic form to the protonated form using the same method as in Example 1, resulting in a CHA-type zeolite with the cationic form being protonated. The IR ratio of the protonated CHA-type zeolite was 0.45, and the NMR ratio was 0.19.

[0120] Example 4 The water treatment temperature was set to 600°C. Otherwise, the CHA-type zeolite of this embodiment was obtained using the same method as in Example 1. The CHA-type zeolite of this embodiment contains a single phase of CHA-type zeolite, with a sodium-potassium cationic form, SiO2 / Al2O3 = 13.9, and an average grain size of 0.49 μm.

[0121] In this embodiment, the CHA-type zeolite was modified by converting the cationic form to the protonated form using the same method as in Example 1, resulting in a CHA-type zeolite with the cationic form being protonated. The IR ratio of the protonated CHA-type zeolite was 0.54, and the NMR ratio was 0.24.

[0122] Comparative Example 1 The precursor CHA obtained by the same method as in Example 1 was treated at 600°C for 2 hours under dry air (0% moisture content by volume) to prepare the CHA-type zeolite of this comparative example.

[0123] The CHA-type zeolite in this comparative example contains a single phase of CHA-type zeolite, with a cationic form of sodium-potassium, a SiO2 / Al2O3 ratio of 13.8, and an average grain size of 0.49 μm.

[0124] Using the same method as in Example 1, cation-type ions were exchanged for H+. + The proton-type CHA zeolite was subjected to IR and NMR measurements. The ion-exchanged CHA-type zeolite corresponds to IR measurements. P1 3599cm -1 The intensity of the peak at the position of the peak and the IR P2 3639cm -1 The intensity of the peak at the position of the peak, IR P2 / IR P1 The ratio is 0.51. Additionally, NMR... P1 and NMRP2 These correspond to the integrated intensities of the peak at 4.2 ppm and the peak at 3.2 ppm, respectively, in NMR. P2 / NMR P1 The ratio is 0.12.

[0125] Example 5 A raw material composition having the following composition is obtained by mixing 49% by mass aqueous solution of CDMEABr, 35% by mass aqueous solution of N,N,N-dimethylethylcyclohexylammonium hydroxide, pure water, 48% by mass aqueous solution of sodium hydroxide, 48% by mass aqueous solution of potassium hydroxide, and amorphous aluminosilicate.

[0126] SiO2 / Al2O3 = 18.5 CDMEA + / SiO2=0.08 (Na+K) / SiO2=0.20 Na / SiO2 = 0.04 K / SiO2 = 0.12 H2O / SiO2 = 18 OH / SiO2 = 0.18.

[0127] After mixing 1.0% by mass of seed crystals, the raw material composition was sealed in a stainless steel autoclave and crystallized at 150°C for 48 hours with stirring at 55 rpm. The obtained crystals were subjected to solid-liquid separation, washed with sufficient pure water, and dried to remove moisture and impurities, serving as the precursor CHA in this embodiment. The precursor CHA contains a single phase of CHA-type zeolite, with a cationic form of sodium-potassium, SiO2 / Al2O3 = 18.9, (Na+K) / Al = 0.36 (2.6% by mass), and an average grain size of 0.78 μm. In addition, the precursor CHA contains CDMEA as SDA. + The SDA content is 0.64.

[0128] The precursor CHA was subjected to a water-containing treatment at 600°C for 2 hours in an atmosphere in which dry air (0% moisture content) mixed with water vapor (air with 67% moisture content) was circulated, thereby producing the CHA-type zeolite of this embodiment. The CHA-type zeolite of this embodiment comprises a single phase of CHA-type zeolite, with a sodium-potassium cationic form, a SiO2 / Al2O3 ratio of 18.9, and an average grain size of 0.78 μm.

[0129] In this embodiment, the CHA-type zeolite was converted from cationic to proton-type using the same method as in Example 1, resulting in a CHA-type zeolite with a proton-type cationic configuration. The IR ratio of the proton-type CHA-type zeolite was 0.71, and the NMR ratio was 0.38.

[0130] Comparative Example 2 The precursor CHA obtained by the same method as in Example 5 was treated at 600°C for 2 hours under a flow of dry air (0% moisture content by volume) to prepare the CHA-type zeolite of this comparative example. The CHA-type zeolite of this comparative example contains a single phase of CHA-type zeolite, with a sodium-potassium cationic form, a SiO2 / Al2O3 ratio of 18.9, and an average grain size of 0.78 μm.

[0131] In this comparative example, the CHA-type zeolite was converted from cationic to proton-type using the same method as in Example 1, resulting in a CHA-type zeolite with a proton-type cationic configuration. The IR ratio of the proton-type CHA-type zeolite was 0.24, and the NMR ratio was 0.23.

[0132] Example 6 Except that the composition of the raw material composition is set as follows and the crystallization temperature is set to 160°C, the precursor CHA of this embodiment is obtained by the same method as in Example 1.

[0133] SiO2 / Al2O3 = 13.2 (TMAdA + +CDMEA + ) / SiO2=0.08 TMAdA + / SiO2=0.01 CDMEA + / SiO2=0.07 (Na+K) / SiO2=0.20 Na / SiO2 = 0.11 K / SiO2 = 0.09 H2O / SiO2 = 15 OH / SiO2 = 0.21 The precursor CHA contains a single phase of CHA-type zeolite, with a cationic form of sodium-potassium, SiO2 / Al2O3 = 13.9, (Na+K) / Al = 0.56 (4.7 mass%), and an average grain size of 0.58 μm.

[0134] The precursor CHA was subjected to a water treatment at 550°C for 2 hours in an atmosphere in which dry air (0% moisture content) mixed with water vapor (air with 17% moisture content) was circulated, thereby producing the CHA-type zeolite of this embodiment.

[0135] The CHA-type zeolite in this embodiment contains a single phase of CHA-type zeolite, with the cationic type being sodium-potassium type, SiO2 / Al2O3 = 13.9, and the average grain size being 0.58 μm.

[0136] In this embodiment, the CHA-type zeolite was modified by converting the cationic form to the protonated form using the same method as in Example 1, resulting in a CHA-type zeolite with the cationic form being protonated. The IR ratio of the protonated CHA-type zeolite was 0.50, and the NMR ratio was 0.18.

[0137] Comparative Example 3 The precursor CHA obtained by the same method as in Example 6 was treated at 600°C for 2 hours under dry air (0% moisture content by volume) to prepare the CHA-type zeolite of this comparative example.

[0138] The CHA-type zeolite in this comparative example contains a single phase of CHA-type zeolite, with a cationic form of sodium-potassium, a SiO2 / Al2O3 ratio of 13.9, and an average grain size of 0.58 μm.

[0139] In this comparative example, the CHA-type zeolite was converted from cationic to proton-type using the same method as in Example 1, resulting in a CHA-type zeolite with a proton-type cationic configuration. The IR ratio of the proton-type CHA-type zeolite was 0.39, and the NMR ratio was 0.08.

[0140] Comparative Example 4 The sodium-potassium cationic CHA-type zeolite obtained by the same method as Comparative Example 1 was used as the precursor CHA. The precursor CHA was subjected to a water treatment at 550°C for 2 hours in an atmosphere in which dry air (0% moisture content) mixed with water vapor (air with 17% moisture content) was circulated, thereby producing the CHA-type zeolite of this Comparative Example.

[0141] The CHA-type zeolite in this comparative example contains a single phase of CHA-type zeolite, with a cationic form of sodium-potassium, a SiO2 / Al2O3 ratio of 13.8, and an average grain size of 0.49 μm.

[0142] In this comparative example, the CHA-type zeolite was converted from cationic to proton-type using the same method as in Example 1, resulting in a CHA-type zeolite with a proton-type cationic configuration. The IR ratio of the proton-type CHA-type zeolite was 0.55, and the NMR ratio was 0.08.

[0143] Comparative Example 5 The sodium-potassium cationic CHA-type zeolite obtained by the same method as in Comparative Example 1 was subjected to ion exchange to obtain a proton-type CHA-type zeolite, which was used as a precursor CHA. This precursor CHA was subjected to a water treatment at 550°C for 2 hours in an atmosphere in which dry air (0% moisture content) mixed with water vapor (air with 17% moisture content) was circulated, thereby producing the CHA-type zeolite of this Comparative Example.

[0144] The CHA-type zeolite of this comparative example contains a single phase of CHA-type zeolite, with the cationic type being proton-type, SiO2 / Al2O3 = 13.8, an average grain size of 0.49 μm, and an IR ratio of 0.82 and an NMR ratio of 0.06.

[0145] Measurement Example 1 After converting the cationic form of the CHA-type zeolites obtained in Examples 1 to 5 and Comparative Example 1 to the proton form, copper nitrate aqueous solution was added dropwise and the mixture was mortared for 10 minutes. After mixing, the mixture was dried overnight at 110°C in the atmosphere and then calcined at 550°C in the atmosphere for 1 hour, thereby producing copper-supported metal-containing CHA-type zeolites (copper-supported CHA-type zeolites). The results are shown in the table below.

[0146] [Table 4]

[0147] (Hydrothermal durability treatment) Copper-supported CHA-type zeolite was shaped and crushed to form aggregated particles with a diameter of 12–20 mesh. 3 mL of the aggregated particles were then filled into a flow-through reaction tube (hereinafter referred to as the "reaction tube") under atmospheric pressure and subjected to hydrothermal durability treatment under the following conditions.

[0148] Processing atmosphere: Circulating air atmosphere with a moisture content of 10% by volume. Airflow rate: 300 mL / min Processing temperature: 900℃ Processing time: 1 hour (Nitrogen oxide reduction rate) 1.5 mL of hydrothermally durable condensed particles was packed into the reaction tube. While maintaining the following measurement temperature, a gas containing nitrogen oxides was passed through the tube, and the nitrogen oxide concentrations at the inlet and outlet of the reaction tube were measured. The gas flow conditions containing nitrogen oxides are described below.

[0149] Composition of nitrogen oxide gases: NO 200ppm NH3 200ppm O210 volume % H2O 3% by volume N2 balance Flow rate of nitrogen oxide-containing gas: 1.5 L / min Space velocity: 60,000hr -1 Measurement temperature: 150℃ or 600℃ The nitrogen oxide concentration was used to calculate the nitrogen oxide reduction rate (NOx reduction rate) using the following formula. Nitrogen oxide reduction rate (%) ={([NOx]in-[NOx]out) / [NOx]in}×100 [NOx]in is the concentration of nitrogen oxides in the nitrogen oxide gas at the inlet of the reaction tube, and [NOx]out is the concentration of nitrogen oxides in the nitrogen oxide gas at the outlet of the reaction tube.

[0150] The ratio of NOx reduction rate of Examples 1 to 4 to NOx reduction rate of Comparative Example 1 (=NOx reduction rate of each Example [%] / NOx reduction rate of Comparative Example 1 [%]) is shown in the table below.

[0151] [Table 5]

[0152] Compared to Comparative Example 1, the embodiment with the water treatment process of this embodiment can confirm NO in either the low temperature region of 150°C or the high temperature region of 600°C. X The reduction rate also increased. In particular, in Example 1, NO at 600°C... X The reduction rate was 1.25 times that of Comparative Example 1, confirming that NO in the high-temperature zone of the water-containing treatment process was reduced. X The reduction rate has been greatly improved.

[0153] Test Example 2 The nitrogen oxide reduction rate was determined using the CHA-type zeolite obtained in Example 5 and Comparative Example 2, with the hydrothermal durability treatment time set to 4 hours and the measurement temperature set to 600°C. Otherwise, NO was determined using the same method as in Example 1. x Reduction rate. The ratio of the NOx reduction rate of Example 5 to the NOx reduction rate of Comparative Example 2 (=NOx reduction rate [%] of each example / NOx reduction rate [%] of Comparative Example 2) is shown in the table below.

[0154] [Table 6]

[0155] Example 5 In Example 5, NO at 600°C XThe reduction rate was 1.15 times that of Comparative Example 2, confirming that NO in the high-temperature zone of the water-containing treatment process was reduced. X The reduction rate has been improved.

[0156] Example 7 The precursor CHA was prepared and subjected to aqueous treatment using the same method as in Example 6 to obtain a CHA-type zeolite with a sodium-potassium cationic form. Ion exchange was performed by treating the obtained CHA-type zeolite with a 2 mol / L hydrochloric acid aqueous solution. Then, it was dried overnight at 110°C in atmospheric conditions to obtain a proton-type CHA-type zeolite, which was used as the CHA-type zeolite in this example. The 50% volume diameter of the CHA-type zeolite in this example is 19.8 μm.

[0157] Example 8 The CHA-type zeolite obtained by crystallization using the same method as that used to produce the precursor CHA in Example 6 was mixed with pure water to obtain a slurry containing 30% by mass of CHA-type zeolite. The slurry was then subjected to continuous wet milling (bead milling) using a continuous bead mill (equipment name: DYNO-MILL typ KDL, manufactured by Shinmaru Enterprises) under the following conditions.

[0158] Grinding medium: 1mm diameter glass beads Filling amount of pulverizing media: 80% by volume Slurry retention time: 1 minute Stirring speed (circumferential speed of the disc): 10 m / s.

[0159] After solid-liquid separation of the pulverized slurry, the recovered solid phase was dried overnight at 110°C in the atmosphere to obtain the precursor CHA of this embodiment. After drying, it underwent aqueous treatment using the same method as in Example 6, performing ion exchange by treating the obtained CHA-type zeolite with a 2 mol / L hydrochloric acid aqueous solution. Then, it was dried overnight at 110°C in the atmosphere to obtain a proton-type CHA-type zeolite, thus obtaining the CHA-type zeolite of this embodiment. The 50% volume diameter of the CHA-type zeolite of this embodiment is 2.4 μm.

[0160] Example 9 CHA-type zeolite with a protonated cationic form was obtained using the same method as in Example 7. It was then pulverized using the same method as in Example 8. After solid-liquid separation of the pulverized slurry, the recovered solid phase was dried overnight in air at 110°C to obtain the CHA-type zeolite of this example. The 50% volume diameter of the CHA-type zeolite of this example is 2.9 μm.

[0161] Comparative Example 6 The precursor CHA obtained by the same method as in Example 6 was treated at 600°C for 2 hours under dry air (0% moisture content by volume) to prepare the CHA-type zeolite of this comparative example.

[0162] The CHA-type zeolite in this comparative example has a SiO2 / Al2O3 ratio of 14.0 and an average grain size of 0.50 μm.

[0163] The CHA-type zeolite of this comparative example was treated with a 2 mol / L hydrochloric acid aqueous solution and subjected to ion exchange, then dried overnight at 110°C in the atmosphere to obtain a CHA-type zeolite with a protonated cationic form. The 50% volume diameter of the protonated CHA-type zeolite was 19.8 μm.

[0164] Comparative Example 7 The precursor CHA obtained by the same method as in Example 8 was treated at 600°C for 2 hours under a flow of dry air (0% moisture content by volume) to obtain CHA-type zeolite. The 50% volume diameter of the CHA-type zeolite in this comparative example is 2.4 μm.

[0165] The CHA-type zeolite of this comparative example was treated with a 2 mol / L hydrochloric acid aqueous solution and subjected to ion exchange. It was then dried overnight in the atmosphere at 110°C to obtain a CHA-type zeolite with a protonated cationic form.

[0166] Test Example 3 The NOx reduction rate was determined using CHA-type zeolites with a protonated cationic form obtained in Examples 7 to 9 and Comparative Examples 6 and 7, omitting the step of setting the cationic form of the CHA-type zeolite to proton, and setting the measurement temperature to 600°C. Otherwise, the NOx reduction rate was determined using the same method as in Example 1. The NOx reduction rates of Examples 7 to 9 and Comparative Example 7 were... X The reduction rate relative to NO in Comparative Example 6 X The reduction rate ratio (= NO of each embodiment or comparative example) X Reduction rate [%] / NO of Comparative Example 6 X The reduction rate (%) is shown in the table below.

[0167] [Table 7]

[0168] In Example 7, NO at 600°C X The reduction rate was 1.02 times that of Comparative Example 6, confirming that the NO reduction in the high-temperature zone was achieved through the water-containing treatment process. X The reduction rate has been improved.

[0169] It can be confirmed that in Comparative Example 7, by performing a pulverization process, NO XThe reduction rate was lower than that of Comparative Example 6. In contrast, in Examples 8 and 9, which underwent water treatment, even after pulverization, the NO reduction rate was lower. X The reduction rate will not decrease.

[0170] The entire contents of the specification, claims and abstract of Japanese Patent Application No. 2020-134632, filed on August 7, 2020, are incorporated herein by reference as disclosure of this publication.

Claims

1. A CHA-type zeolite, characterized in that, 1 In the 1H-MAS-NMR spectrum, the integrated intensity of the largest peak at chemical shifts of 3.0–3.5 ppm is greater than 0.12 and less than 0.5 relative to the integrated intensity of the largest peak at chemical shifts of 4.0–4.5 ppm. Furthermore, in the IR spectrum, at a wavenumber of 3630 cm⁻¹… -1 Above and 3650cm -1 The following absorption peaks have maximum peak heights relative to wavenumber 3590 cm⁻¹. -1 Above and 3610cm -1 The ratio of the maximum peak height of the absorption peaks with the following positions is 0.40 or higher and 1.0 or lower, and the molar ratio of silicon dioxide to aluminum oxide is 8.0 or higher and 50.0 or lower. The CHA-type zeolite is manufactured by a manufacturing method comprising the following steps: The process of manufacturing CHA-type zeolite precursors by crystallizing a composition containing an organic structure-directing agent and having the following molar composition, and The process of treating the CHA-type zeolite precursor containing the organic structure directing agent under an aqueous atmosphere. The SiO2 / Al2O3 ratio is greater than 5.0 and less than 20.

0. The ratio of organic structure directing agent to SiO2 is greater than 0.06 and less than 0.

12. The ratio of alkali metal elements to SiO2 is greater than 0.10 and less than 0.

30. The H2O / SiO2 ratio is above 8.0 and below 25.

0.

2. The CHA-type zeolite according to claim 1, wherein, In the IR spectrum, at a wavenumber of 3630 cm⁻¹ -1 Above and 3650cm -1 The following absorption peaks have maximum peak heights relative to wavenumber 3590 cm⁻¹. -1 Above and 3610cm -1 The ratio of the maximum peak height of the following absorption peaks is 0.55 or higher and 1.0 or lower.

3. The CHA-type zeolite according to claim 1 or 2, wherein, In the 1 In H-MAS-NMR spectra, the ratio of the integrated intensity of the largest peak with a chemical shift of 3.0–3.5 ppm to the integrated intensity of the largest peak with a chemical shift of 4.0–4.5 ppm is greater than 0.13 and less than 0.

5.

4. The CHA-type zeolite according to claim 1 or 2, wherein, The molar ratio of silicon dioxide to aluminum oxide is greater than 12.0 and less than 20.

0.

5. The CHA-type zeolite according to claim 1 or 2, wherein, The CHA-type zeolite contains transition metal elements.

6. A method for manufacturing CHA-type zeolite, characterized in that, The manufacturing method has the following characteristics: The process of manufacturing CHA-type zeolite precursors by crystallizing a composition containing an organic structure-directing agent and having the following molar composition, and The process of treating the CHA-type zeolite precursor containing the organic structure directing agent under an aqueous atmosphere. The SiO2 / Al2O3 ratio is greater than 5.0 and less than 20.

0. The ratio of organic structure directing agent to SiO2 is greater than 0.06 and less than 0.

12. The ratio of alkali metal elements to SiO2 is greater than 0.10 and less than 0.

30. The H2O / SiO2 ratio is above 8.0 and below 25.

0.

7. The manufacturing method according to claim 6, wherein, The organic structure directing agent is selected from one or more of N,N,N-trialkyladamantane ammonium cation, N,N,N-trimethylbenzylammonium cation, N-alkyl-3-quinol cation, N,N,N-trialkylexoaminonorbornene cation and N,N,N-trialkylcyclohexylammonium cation.

8. The manufacturing method according to claim 6 or 7, wherein, The molar ratio of silica to alumina in the CHA-type zeolite precursor is 8.0 or higher and 30.0 or lower.

9. The manufacturing method according to claim 6 or 7, wherein, The cationic form of the CHA-type zeolite precursor is sodium-potassium type.

10. The manufacturing method according to claim 6 or 7, wherein, The content of alkali metal elements in the CHA-type zeolite precursor is 0.1% by mass or more.

11. The manufacturing method according to claim 6 or 7, wherein, The water-containing atmosphere is an air atmosphere in which the water content relative to the saturated water vapor content is more than 5% by volume and less than 95% by volume.

12. The manufacturing method according to claim 6 or 7, wherein, The water treatment involves placing the CHA-type zeolite precursor in a calcining furnace and then heating it to the water treatment temperature.

13. The manufacturing method according to claim 6 or 7, wherein, The water treatment involves introducing the CHA-type zeolite precursor into a calcining furnace that has been heated to the water treatment temperature.

14. The manufacturing method according to claim 6 or 7, wherein, The water-containing treatment temperature is above 400℃.

15. A CHA-type zeolite, characterized in that, It is obtained by the manufacturing method according to any one of claims 6 to 14.

16. The CHA-type zeolite according to claim 15, wherein, In the IR spectrum, at a wavenumber of 3630 cm⁻¹ -1 Above and 3650cm -1 The following absorption peaks have maximum peak heights relative to wavenumber 3590 cm⁻¹. -1 Above and 3610cm -1 The ratio of the maximum peak height of the following absorption peaks is 0.55 or higher and 1.0 or lower.

17. A nitrogen oxide reduction catalyst, characterized in that, It includes CHA-type zeolite as described in any one of claims 1 to 5, 15, and 16.

18. A method for reducing nitrogen oxides, characterized in that, Use the CHA type zeolite as described in any one of claims 1 to 5, 15, and 16.

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