Method for producing CHA type zeolite

Abstract

To provide a production method capable of obtaining a CHA type zeolite rich in aluminum which functions as an acid point in comparison to a conventional CHA type zeolite obtained using an N,N,N-trimethyl-1-adamantane cation as a structure directing agent.SOLUTION: A method for producing CHA type zeolite includes: a crystallizing process of crystallizing a composition including an N,N,N-trialkylcyclohexyl ammonium cation source, an alumina source, a silica source, a sodium source, a cerium source, and water where the mole ratio of silica to alumina is 30 or less, to obtain a crystallized material; a calcining process of calcining the crystallized material at a temperature of 400°C or higher and 700°C or lower to obtain a calcined product; and an alkali-removing process of contacting the calcined product with an ammonium salt-containing solution.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a method for producing CHA-type zeolites using N,N,N-trialkylcyclohexylammonium cations as structure directing agents. [Background technology]

[0002] Artificially synthesized CHA-type zeolites are used as catalysts such as nitrogen oxide reduction catalysts and petrochemical catalysts. Various methods for producing CHA-type zeolites have been proposed so far, including methods using expensive structure-directing agents such as N,N,N-trimethyl-1-adamantane cations and methods using inexpensive structure-directing agents such as N,N,N-trialkylcyclohexylammonium cations (e.g., Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US Patent No. 2008 / 0045767 [Patent Document 2] US Patent No. 2019 / 0105639 Summary of the Invention [Problem to be solved by the invention]

[0004] In CHA zeolites, the aluminum contained in the framework functions as an acid site. Therefore, the nitrogen oxide reduction activity tends to increase as the amount of aluminum increases. However, as a result of investigations by the present inventors, it was confirmed that conventional CHA zeolites obtained using N,N,N-trimethyl-1-adamantane cations as a structure-directing agent have little aluminum that functions as an acid site, even when they contain a large amount of aluminum.

[0005] The present disclosure aims to provide a production method for obtaining CHA-type zeolites that have a higher content of aluminum that functions as acid sites than conventional CHA-type zeolites obtained using N,N,N-trimethyl-1-adamantane cations as a structure-directing agent. [Means for solving the problem]

[0006] The present inventors have investigated the crystallization conditions in a method for producing CHA-type zeolite using N,N,N-trialkylcyclohexylammonium cations as a structure-directing agent, and have found that by using a specific composition for crystallization and containing specific elements, the amount of aluminum that functions as an acid site increases.

[0007] That is, the present invention is as defined in the claims, and the gist of the present disclosure is as follows. [1] A method for producing CHA-type zeolite, comprising: a crystallization step of crystallizing a composition containing an N,N,N-trialkylcyclohexylammonium cation source, an alumina source, a silica source, a sodium source, a cerium source, and water, wherein the molar ratio of silica to alumina is 30 or less, to obtain a crystallized product; a calcination step of calcining the crystallized product at 400°C or higher and 700°C or lower to obtain a calcined product; and an alkali removal step of contacting the calcined product with an ammonium salt-containing solution. [2] The method for producing CHA-type zeolite according to [1], wherein the composition has at least the following molar composition:

[0008] SiO2 / Al2O3 ratio: 3 or more and 30 or less TACH + / SiO2 ratio: 0.01 or more and 0.5 or less Na / SiO2 ratio: more than 0 and less than 0.60 Ce / SiO2 ratio: more than 0 and less than 0.05 H2O / SiO2 ratio: 3 or more and 50 or less OH / SiO2 ratio: 0.10 or more and 1.50 or less However, TACH +represents an N,N,N-trialkylcyclohexylammonium cation. [3] The method for producing a CHA-type zeolite according to [1] or [2], wherein the composition contains one or more selected from the group consisting of an N,N,N-trialkyladamantanammonium cation source, a trimethylbenzylammonium cation source, and a tetraethylammonium cation source. [Effects of the Invention]

[0009] The present disclosure provides a production method for obtaining CHA-type zeolites that have more acid sites and functional aluminum than conventional CHA-type zeolites obtained using N,N,N-trialkylcyclohexylammonium cations as a structure-directing agent. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 2 is a scanning electron microscope image of the cerium-containing CHA-type zeolite of Example 1. [Figure 2] FIG. 2 is a scanning electron microscope image of the cerium-containing CHA-type zeolite of Example 2. [Figure 3] FIG. 2 is a scanning electron microscope image of the cerium-containing CHA-type zeolite of Example 3. [Figure 4] FIG. 2 is a scanning electron microscope image of the cerium-containing CHA-type zeolite of Comparative Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0011] The method for producing CHA-type zeolite of the present disclosure will be described below with reference to an example embodiment. The configurations and parameters disclosed in this specification can be arbitrarily combined, and the upper and lower limits of the values ​​disclosed in this specification can be arbitrarily combined.

[0012] The terms used in this embodiment are as follows:

[0013] "Zeolite" refers to a compound having a regular structure in which skeleton atoms (hereinafter also referred to as "T atoms") are connected via oxygen (O), and the T atoms are at least one of metal atoms and metalloid atoms. Examples of metal atoms include one or more atoms selected from the group consisting of aluminum (Al), titanium (Ti), iron (Fe), zinc (Zn), gallium (Ga), and tin (Sn), with aluminum being preferred. Examples of metalloid atoms include one or more atoms selected from the group consisting of boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), and tellurium (Te), with silicon being preferred.

[0014] "Zeolite-like substances" are compounds with a regular structure in which T atoms are oxygen-mediated, and the T atoms contain at least one atom other than a metal or semimetal (hereinafter also referred to as a "non-metal atom"). Examples of non-metal atoms include phosphorus (P), and examples of zeolite-like substances include complex phosphorus compounds such as aluminophosphate (AlPO) and silicoaluminophosphate (SAPO).

[0015] The "regular structure in which T atoms are oxygen-mediated (hereinafter also referred to as "zeolite structure")" of zeolites and zeolite-like substances is a skeletal structure identified by the structure code (hereinafter also referred to simply as "structure code") established by the Structure Commission of the International Zeolite Association. For example, the CHA structure is a skeletal structure identified by the structure code "CHA." Zeolite structures can be identified by comparing the XRD patterns of each structure (hereinafter also referred to as "reference patterns") described in "Collection of simulated XRD powder patterns for zeolites, Fifth revised edition (2007)." In this embodiment, the terms "skeletal structure," "crystalline structure," and "crystalline phase" are used interchangeably.

[0016] An "aluminosilicate" is a composite oxide having a structure consisting of a repeating network of aluminum (Al) and silicon (Si) via oxygen (O). In this embodiment, aluminosilicates also include those having a structure consisting of a repeating network of aluminum (Al) and silicon (Si) via oxygen (O), and in which a portion of the aluminum (e.g., 30% or less of the aluminum as T atoms) is substituted with another metal atom. Among aluminosilicates, those that have a crystalline XRD peak in their powder X-ray diffraction (hereinafter also referred to as "XRD") pattern are called "crystalline aluminosilicates," and those that do not have a crystalline XRD peak are called "amorphous aluminosilicates."

[0017] In this embodiment, the XRD pattern is measured using CuKα radiation as a radiation source, and the measurement conditions include the following.

[0018] Acceleration current / voltage: 40mA / 40kV Radiation source: CuKα radiation (λ=1.5405Å) Measurement mode: Continuous scan Scan condition: 40° / min Measurement range: 2θ=3° to 43° Divergence vertical limit slit: 10mm Divergence / entrance slit: 1° Receiving slit: open Receiving solar slit: 5° Detector: Semiconductor detector (D / teX Ultra) Filter: Ni filter The XRD pattern can be measured using a general powder X-ray diffractometer (e.g., Ultima IV, manufactured by Rigaku Corporation). The crystalline XRD peak is a peak detected by identifying the 2θ of the peak top in an XRD pattern analysis using general analysis software (e.g., SmartLab Studio II, manufactured by Rigaku Corporation), and an example of such a peak is an XRD peak with a half-width of 2θ = 0.10° or less.

[0019] As the analysis conditions of the XRD pattern, the following conditions can be mentioned.

[0020] Fitting condition: Automatic, refine background Dispersed pseudo-Voigt function (peak shape) Background removal method: Fitting method Kα2 removal method: Kα1 / Kα2 ratio = 0.497 Smoothing method: B-Spline curve Smoothing condition: Second derivative method, σ cut-off value = 3, χ threshold value = 1.5 The composition in this embodiment, such as the molar ratio of silica to alumina, may be measured by ICP analysis using a general inductively coupled plasma optical emission spectrometer (for example, OPTIMA 7300DV, manufactured by PERKIN ELMER).

[0021] The "remaining acid amount ratio" is the Bronsted acid amount of the zeolite, and it may be a value calculated from the ratio of the Bronsted acid amount of the CHA-type zeolite measured by the NH3-TPD method to the theoretical acid amount of the CHA-type zeolite.

[0022] The NH3-TPD measurement may be performed under the following measurement conditions using a general temperature-programmed desorption analyzer (for example, apparatus name: BELCAT II, manufactured by MicrotracBEL). <Measurement sample> Measurement sample: 0.05 g <Pretreatment> Atmospheric gas type: Helium Gas flow rate: 50 ml / min Treatment temperature: 500 °C Treatment time: 60 minutes <NH3-TPD measurement> A mixed gas containing 1% by volume ammonia and 99% by volume helium gas is passed through the measurement sample at 100°C to allow ammonia to adsorb to saturation. After passing the mixed gas for 30 minutes, the mixed gas is replaced with helium gas, which is passed for 15 minutes to remove any remaining ammonia in the atmosphere. After the remaining ammonia is removed, the sample is heated to 710°C at a rate of 10°C / min under a helium flow rate of 30 mL / min. This causes the ammonia adsorbed on the sample to desorb from the sample. The ammonia desorbed from the sample is continuously quantified using a gas chromatograph equipped with a thermal conductivity detector (TCD), thereby obtaining an ammonia desorption spectrum (TPD spectrum).

[0023] The obtained TPD spectrum is analyzed using common analytical software (e.g., Chem Master, Microtrac for Windows ver. 1.4.9, Microtrac) and baseline processing is performed with 700°C as the base end. The baseline-processed spectrum is then subjected to waveform decomposition using Gaussian distribution, dual waveform decomposition, and DFP. Of the two spectra obtained, the area of ​​the spectrum with a peak top in the range of 300°C to 700°C is taken as the ammonia desorption spectrum. The area (integral value) of this spectrum is calculated and used as the amount of ammonia desorption (mmol). The amount of ammonia desorption (mmol) can be divided by the weight (g) of the sample used in the measurement to obtain the Brønsted acidity of the sample (Al-BAS: mmol / g).

[0024] The theoretical acid amount (mmol / g) of CHA zeolite is the theoretical value of the molar amount of Al per mass (Al-zeo:mmol / g) calculated from the composition of CHA zeolite, and can be calculated using the following formula (1):

[0025] Theoretical acidity of CHA-type zeolite (mmol / g) = {101.96 / (60.08×A+101.96)} / 101.96×2×1000 (1) However, in the above formula, A represents the molar ratio of silica to alumina in the CHA-type zeolite (hereinafter also referred to as the "SiO2 / Al2O3 ratio").

[0026] The "average crystal diameter" is the average value of the particle diameters of the primary particles. The primary particles are the smallest unit particles that can be independently observed by scanning electron microscopy (hereinafter also referred to as "SEM") under the following conditions. The SEM observation may be performed using a general scanning electron microscope (for example, apparatus name: JSM-IT200, manufactured by JEOL Ltd.).

[0027] Acceleration voltage: 6 kV Magnification: 10,000 ± 5,000 times The average crystal diameter may be measured by measuring the longest diameter of the smallest unit particles that can be independently observed. When the particles are rhombohedrons or cubes, the diagonal line thereof may be measured, and when they are amorphous, the longest diameter thereof may be measured, and the arithmetic mean of 50 ± 5 may be calculated. However, the secondary aggregates (aggregates) in which the primary particles are aggregated are not used as independent particles for calculating the average crystal diameter.

[0028] <Manufacturing method of CHA-type zeolite> Hereinafter, the manufacturing method of the CHA-type zeolite of the present embodiment will be described.

[0029] If The present embodiment is a method for producing a CHA-type zeolite, which includes a crystallization step of crystallizing a composition containing a N,N,N-trialkylcyclohexylammonium cation source, an alumina source, a silica source, a sodium source, a cerium source, and water, and having a molar ratio of silica to alumina of 30 or less to obtain a crystallized product, a firing step of firing the crystallized product at 400°C or higher and 700°C or lower to obtain a fired product, and an alkali removal step of bringing the fired product into contact with an ammonium salt-containing solution. (Crystallization step) The method for producing CHA-type zeolite of this embodiment includes a crystallization step of crystallizing a composition (hereinafter also referred to as the "raw material composition") containing an N,N,N-trialkylcyclohexylammonium cation source, an alumina source, a silica source, a sodium source, a cerium source, and water, and having a molar ratio of silica to alumina of 30 or less, to obtain a crystallized product.

[0030] It is believed that by crystallizing a raw material composition containing a cerium source in the crystallization process, CHA-type zeolite is crystallized while some or all of the cerium (Ce) is incorporated in a state that is less likely to reduce the acidity of the CHA-type zeolite.

[0031] In order to crystallize the CHA-type zeolite of this embodiment, the molar ratio of silica to alumina (SiO2 / Al2O3 ratio) of the raw material composition is 30 or less, and may be 3 or more and 30 or less, 3 or more and 28 or less, 3 or more and 26 or less, 3 or more and 23 or less, 3 or more and 20 or less, 3 or more and 15 or less, 5 or more and 30 or less, 5 or more and 28 or less, 5 or more and 26 or less, 5 or more and 23 or less, 5 or more and 20 or less, 5 or more and 15 or less, 8 or more and 30 or less, 8 or more and 28 or less, 8 or more and 26 or less, 8 or more and 23 or less, 8 or more and 20 or less, or 8 or more and 15 or less. Furthermore, 5 or more and 26 or less is preferable, and 8 or more and 26 or less is more preferable.

[0032] The raw material composition contains N,N,N-trialkylcyclohexylammonium cation (hereinafter referred to as "TACH + This allows for the production of CHA-type zeolite at lower cost than production methods that use only N,N,N-trimethyl-1-adamantane cation as an organic structure directing agent (hereinafter also referred to as "SDA"). + Specific TACH included in the source + As the cation, N,N,N-trimethylcyclohexylammonium cation (hereinafter referred to as "TMCH + "), N,N,N-dimethylethylcyclohexylammonium cation (hereinafter referred to as "DMECH + "), N,N,N-methyldiethylcyclohexylammonium cation (hereinafter referred to as "MDECH +") and N,N,N-triethylcyclohexylammonium cation (hereinafter referred to as "TECH + ") group, and DMECH + and MDECH + At least one of the above is preferred, and DMECH + or MDECH + is more preferred, and DMECH + is more preferred.

[0033] TACH contained in the raw material composition + The source may be two or more, etc. + If there are two or more sources, DMECH + Source, MDECH + Source & Tech + Preferably, two or more selected from the group of DMECH + Source & MDECH + Source is more preferable.

[0034] TACH + Source: TACH + and salts containing, for example, TACH + Examples of the hydroxide include one or more selected from the group consisting of hydroxides, halides, carbonate monoester salts, and sulfate monoester salts; one or more selected from the group consisting of hydroxides, chlorides, bromides, and iodides; one or more selected from the group consisting of hydroxides, bromides, and iodides; at least one of hydroxides and bromides; or hydroxide.

[0035] The raw material composition contains TACH as SDA. + However, in order to further improve the yield of CHA-type zeolite, it is preferable to use TACH as an SDA for directing the CHA structure, as long as it is within the range that is commensurate with the industrial production cost. + The SDA may contain an SDA other than the above (hereinafter also referred to as "Add-SDA"). As the Add-SDA, N,N,N-trialkyladamantanammonium cation (hereinafter referred to as "TAAd +"). ) source, trimethylbenzylammonium cation source, and tetraethylammonium cation source (Add-SDA cation source), and one or more selected from the group consisting of a cation source. Specific examples of TAAd + The source of Add-SDA is N,N,N-trimethyl-1-adamantanammonium cation. When the raw material composition contains an Add-SDA source, TACH + It is preferred to include Add-SDA in a smaller proportion than the source.

[0036] The Add-SDA source is a salt containing the Add-SDA cation, and examples thereof include one or more selected from the group consisting of hydroxide, halide, carbonate monoester salt, and sulfate monoester salt of the Add-SDA cation; one or more selected from the group consisting of hydroxide, chloride, bromide, and iodide; one or more selected from the group consisting of hydroxide, bromide, and iodide; at least one of hydroxide and bromide; or hydroxide.

[0037] Mainly TACH + In order to crystallize CHA-type zeolite by the structure-directing effect of + The molar ratio of Add-SDA to TACH (hereinafter referred to as "Add-SDA / TACH") + The Add-SDA / SDA ratio may be 0 or more and 1 or less, more than 0 and less than 1, or 0.05 or more and 0.5 or less. The raw material composition may not contain Add-SDA, and the Add-SDA / SDA ratio may be 0 (zero).

[0038] The alumina source is at least one of alumina (Al2O3) and a precursor thereof, and examples thereof include one or more selected from the group consisting of alumina, aluminum sulfate, aluminum nitrate, sodium aluminate, aluminum chloride, aluminum hydroxide, amorphous aluminosilicate, metallic aluminum, crystalline aluminosilicate, and aluminum alkoxide. Further, at least one of an amorphous aluminum compound, aluminum hydroxide, a crystalline aluminosilicate, and an amorphous aluminosilicate, or even an amorphous aluminosilicate, is preferred.

[0039] The silica source is at least one of silica (SiO2) and a precursor thereof, and examples thereof include one or more selected from the group consisting of colloidal silica, amorphous silica, sodium silicate, tetraethoxysilane, tetraethyl orthosilicate, precipitated silica, fumed silica, amorphous aluminosilicate, and crystalline aluminosilicate. At least one of crystalline aluminosilicate and amorphous aluminosilicate, and even amorphous aluminosilicate are preferred.

[0040] At least one of the alumina source and the silica source preferably contains an amorphous aluminosilicate, and it is more preferable that both the alumina source and the silica source contain an amorphous aluminosilicate, which tends to reduce production costs and is industrially advantageous.

[0041] The sodium source may be a salt or compound containing sodium. The salt or compound containing sodium may be one or more selected from the group consisting of chloride, iodide, bromide, hydroxide, and oxide of sodium, preferably one or more selected from the group consisting of chloride, bromide, and hydroxide of sodium, more preferably sodium hydroxide. Sodium contained in other starting materials may also be considered as a sodium source. The raw material composition preferably contains at least sodium hydroxide.

[0042] The raw material composition may contain a source of an alkali metal other than sodium. Examples of sources of alkali metal other than sodium include compounds containing alkali metal elements other than sodium. Examples of salts or compounds containing alkali metal elements other than sodium include one or more selected from the group consisting of chlorides, iodides, bromides, sulfates, hydroxides, and oxides of alkali metals other than sodium. Preferred are one or more selected from the group consisting of chlorides, bromides, and hydroxides of alkali metals other than sodium, and more preferred are hydroxides of alkali metals other than sodium. In addition, alkali metals other than sodium contained in other starting materials can also be considered sources of alkali metals other than sodium.

[0043] Examples of alkali metal elements other than sodium include one or more selected from the group consisting of lithium, potassium, rubidium, and cesium. In terms of the tendency to reduce the amount of silanol defects, the alkali metal elements other than sodium are preferably one or more selected from the group consisting of lithium, potassium, and cesium, more preferably at least one of potassium and cesium, and even more preferably potassium.

[0044] The cerium source may be a salt or compound containing cerium. Examples of the salt or compound containing cerium include one or more selected from the group consisting of chloride, iodide, bromide, nitrate, acetate, sulfate, carbonate, hydroxide, and oxide of cerium. One or more selected from the group consisting of chloride, nitrate, acetate, sulfate, carbonate, and hydroxide of cerium is preferred, with cerium nitrate being more preferred. Cerium contained in other starting materials can also be considered a cerium source. The raw material composition preferably contains at least cerium nitrate.

[0045] The raw material composition may contain alkali metals other than sodium, that is, one or more selected from the group consisting of potassium, rubidium, and cesium, in order to obtain the CHA structure.

[0046] The water contained in the raw material composition may be deionized water or pure water, or may be structured water, water as a solvent, or water (H2O) contained in other starting materials.

[0047] The raw material composition preferably does not contain fluorine (F) or phosphorus (P), and the fluorine and phosphorus contents of the raw material composition are each below the detection limit (for example, the fluorine content is 1 ppm by mass or less, the phosphorus content is 1 ppm by mass or less, or the total content of fluorine and phosphorus is 1 ppm by mass or less).

[0048] The preferred composition of the raw material composition is the following molar composition: + DMECH + TACH when etc. + / SiO2 ratio is DMECH+ In addition, when M is an alkali metal other than sodium and the raw material composition contains two or more alkali metals other than sodium (for example, potassium and cesium), the M / SiO2 ratio may be considered as a (K+Cs) / SiO2 ratio, etc. Furthermore, each composition ratio in the molar composition may be any combination of the upper and lower limits described below.

[0049] SiO2 / Al2O3 ratio: 3 to 30, 3 to 28, 3 to 26, 3 to 23, 3 to 20, 3 to 15, 5 to 30, 5 to 28, 5 to 26, 5 to 23, 5 to 20, 5 to 15, 8 to 30, 8 to 28, 8 to 26, 8 to 23, 8 to 20 or 8 to 15 TACH + / SiO2 ratio: 0.01 or more and 0.50 or less, 0.01 or more and 0.30 or less, 0.01 or more and 0.20 or less, 0.01 or more and 0.10 or less, 0.02 or more and 0.5 or less, 0.02 or more and 0.30 or less, 0.02 or more and 0.20 or less, 0.02 or more and 0.10 or less, 0.05 or more and 0.5 or less, 0.05 or more and 0.30 or less, 0.05 or more and 0.20 or less, 0.05 or more and 0.10 or less, 0.07 or more and 0.5 or less, 0.07 or more and 0.30 or less, 0.07 or more and 0.20 or less, or 0.07 or more and 0.10 or less.

[0050] Add-SDA / TACH + Ratio: 0 or more and 1 or less, 0 or more and 0.5 or less, 0 or more and 0.4 or less, 0.05 or more and 1 or less, 0.05 or more and 0.5 or less, or 0.05 or more and 0 or less and 1 or less, 0.5 or less, or 0.4 or less Na / SiO2 ratio: More than 0 and up to 0.60, more than 0 and up to 0.50, more than 0 and up to 0.30, 0.03 to 0.60, 0.03 to 0.50, 0.03 to 0.30, 0.06 to 0.60, 0.06 to 0.50, or 0.06 to 0.30. More than 0, 0.03 or 0.06 or more, and up to 0.60, 0.5 or less, 0.4 or less, or 0.3 or less M / SiO2 ratio: 0 or more and 0.60 or less, 0 or more and 0.50 or less, 0 or more and 0.30 or less, 0.03 or more and 0.60 or less, 0.03 or more and 0.50 or less, 0.03 or more and 0.30 or less, 0.06 or more and 0.60 or less, 0.06 or more and 0.50 or less, or 0.06 or more and 0.30 or less.

[0051] Ce / SiO2 ratio: greater than 0 and less than 0.05, greater than 0 and less than 0.03, greater than 0 and less than 0.015, 0.001 or more and less than 0.05, 0.001 or more and less than 0.03, 0.001 or more and less than 0.015, 0.005 or more and less than 0.05, 0.005 or more and less than 0.03, or 0.005 or more and less than 0.015.

[0052] H2O / SiO2 ratio: 3 or more and 50 or less, 3 or more and 30 or less, 3 or more and 20 or less, 3 or more and 19 or less, 5 or more and 50 or less, 5 or more and 30 or less, 5 or more and 20 or less, 5 or more and 19 or less, 10 or more and 50 or less, 10 or more and 30 or less, 10 or more and 20 or less, or 10 or more and 19 or less.

[0053] OH / SiO2 ratio :0.10 to 1.50, 0.10 to 1.00, 0.10 to 0.80, 0.10 to 0.60, 0.10 to 0.45, 0.12 to 1.50, 0.12 to 1.00, 0.12 0.80 or more, 0.12 or more and 0.60 or less, 0.12 or more and 0.45 or less, 0.15 or more and 1.50 or less, 0.15 or more and 1.00, 0.15 or more and 0.80, 0.15 or more and 0.60 or less, 0.15 or more and 0.45 or less.

[0054] The raw material composition may contain seed crystals to promote the crystallization of CHA zeolite. Examples of seed crystals include one or more selected from the group consisting of AEI zeolite, AFX zeolite, ERI zeolite, CHA zeolite, LEV zeolite, and OFF zeolite, and an example of which is CHA zeolite. When the raw material composition contains seed crystals, the ratio of the total mass of silicon (Si) and aluminum (Al) of the seed crystals, converted into SiO and AlO, respectively, to the total mass of silicon (Si) and aluminum (Al) of the raw material composition, converted into SiO and AlO, respectively (hereinafter also referred to as the "seed crystal content") may be 0 to 10% by mass, 0 to 5% by mass, or 0 to 3% by mass. The raw material composition may not contain seed crystals, i.e., the seed crystal content may be 0% by mass.

[0055] In the crystallization step, the raw material composition is crystallized to obtain a crystallized product (CHA-type zeolite). The crystallization method may be any method that crystallizes the raw material composition, and may be hydrothermal synthesis. Examples of conditions for hydrothermal synthesis include the following:

[0056] Crystallization temperature: 130 to 200°C, 140 to 180°C, or 150 to 170°C.

[0057] Crystallization time: 1 hour or more, 10 hours or more, 10 hours or more and 1 hour or more, 10 hours or more, or 24 hours or more, and 7 days or less, 5 days or less, 3 days or less, or 2 days or less Crystallization state: at least one of a stirring state and a static state, or a stirring state Crystallization pressure: Autogenous pressure For example, when crystallizing CHA-type zeolite with an SiO2 / Al2O3 ratio of 30 or less, if the crystallization temperature is 130 to 200°C, single-phase CHA-type zeolite can be crystallized in 2 days or less. (Firing process) The method for producing CHA-type zeolite of this embodiment includes a calcination step of calcining the crystallized product obtained in the crystallization step at a temperature of 400° C. or higher and 700° C. or lower. As a result, the TACH contained in the crystallized product (CHA-type zeolite) is reduced. + A fired product can be obtained from which the TACH has been removed. + can be removed from the crystallized product (CHA-type zeolite).

[0058] The firing atmosphere is TACH + The atmosphere may be any atmosphere capable of removing the carbon monoxide, and may be at least one of an oxidizing atmosphere, an inert atmosphere, and a reducing atmosphere, and is preferably an oxidizing atmosphere, or more preferably an air atmosphere.

[0059] SDA removal from crystallized material + Any method capable of removing SDA may be used. SDA removal methods include at least one of calcination and acid treatment, with calcination being preferred. Examples of calcination include treating CHA-type zeolite in one or more atmospheres selected from the group consisting of an oxidizing atmosphere, an inert atmosphere, and a reducing atmosphere at 400°C to 700°C. Particularly preferred calcination methods include calcination in an air atmosphere at 550°C to 650°C. The calcination (and acid treatment) time can be, for example, from 1 hour to 5 hours, but may be adjusted appropriately depending on the amount of crystallized material to be subjected to the calcination.

[0060] The crystallized material to be subjected to the firing step may be one recovered by solid-liquid separation or the like after the crystallization step, but may also be one that has been washed and dried.

[0061] The crystallized product can be washed by any method after crystallization. After the crystallization step, the crystallized product obtained as a solid phase can be washed with pure water in an amount such that the mass of the pure water is at least 1 times the total mass of the raw material composition excluding seed crystals used for crystallization. For example, if the total mass of the raw material composition is 60 g, washing can be done with at least 60 g of pure water, regardless of whether seed crystals are added or not.

[0062] Drying can be performed by any method that can remove moisture physically adsorbed on the CHA-type zeolite, and examples include treating the CHA-type zeolite in at least one of an oxidizing atmosphere and an inert atmosphere at 100°C or higher and 200°C or lower for 2 hours or more. (Alkali removal process) The method for producing CHA-type zeolite of this embodiment includes an alkali removal step in which the calcined product obtained in the calcination step is brought into contact with an ammonium salt-containing solution, thereby removing alkali metals such as sodium contained in the calcined product.

[0063] In the alkali removal step, the fired product obtained in the firing step may be brought into contact with an ammonium salt-containing solution so that the amount of ammonia is such that the alkali metal can be sufficiently removed.

[0064] The ammonium-containing solution contains ammonium (NH4 + ) and a solvent.

[0065] The solvent may be any medium in which the ammonium salt dissolves, and may be at least one of alcohol and water, and is preferably water, that is, the ammonium-containing solution is preferably an aqueous ammonium-containing solution.

[0066] Ammonium salts are ammonium (NH4 + ) may be used, and examples thereof include inorganic salts of ammonium, and further, one or more selected from the group consisting of ammonium carbonate, ammonium chloride and ammonium nitrate, and further, ammonium chloride.

[0067] The ammonium-containing solution is + The concentration is preferably 1% by mass or more and 30% by mass or less, and more preferably 5% by mass or more and 20% by mass or less.

[0068] In order to sufficiently remove alkali metals from the fired product after the firing process, the ratio of the mass of the ammonium-containing solution to the mass of the fired product (CHA-type zeolite not containing SDA, hereinafter also referred to as "NH4 / CHA") is preferably 10 or less, 8 or less, or 6 or less. NH4 / CHA may exceed 1, and may be 1.5 or more, or 2 or more.

[0069] <CHA-type zeolite> The zeolite obtained by the method for producing a CHA-type zeolite of the present embodiment includes a CHA-type zeolite containing cerium (hereinafter also referred to as "cerium-containing CHA-type zeolite"). Hereinafter, the CHA-type zeolite produced by the CHA-type zeolite production method of the present embodiment (hereinafter also simply referred to as "the cerium-containing CHA-type zeolite of the present embodiment") will be described.

[0070] The cerium-containing CHA-type zeolite of the present embodiment preferably has a SiO2 / Al2O3 ratio of 3 or more and 30 or less. By having the SiO2 / Al2O3 ratio within the above range, it can be expected as a carrier that exhibits high SCR catalyst performance and durability. As the SiO2 / Al2O3 ratio of the cerium-containing CHA-type zeolite of the present embodiment, 5 or more and 25 or less is more preferable, and 8 or more and 25 or less is more preferable.

[0071] In the cerium-containing CHA-type zeolite of this embodiment, the cerium content (hereinafter also referred to as the "CeO2 content") calculated as CeO2 is preferably 0.01% by mass or more and 6.0% by mass or less relative to the total content (hereinafter also referred to as the "metal content") of the cerium-containing CHA-type zeolite including the silicon (Si) content calculated as SiO2, the aluminum (Al) content calculated as Al2O3, the sodium (Na) content calculated as Na2O, the alkali metals other than sodium (M) content calculated as MO, and the cerium (Ce) content calculated as CeO2. With the CeO2 content at the above value, high heat resistance can be expected. The CeO2 content of the CHA-type zeolite of this embodiment is more preferably 0.01% by mass or more and 5.0% by mass or less, more preferably 0.03% by mass or more and 4.5% by mass or less, and even more preferably 0.05% by mass or more and 4.0% by mass or less.

[0072] In the cerium-containing CHA-type zeolite of this embodiment, the sodium content calculated as NaO (hereinafter also referred to as "NaO content") relative to the metal content is preferably 0% by mass or more and 0.20% by mass or less, more preferably more than 0% by mass and 0.10% by mass or less, and even more preferably more than 0% by mass and 0.06% by mass or less.

[0073] In the cerium-containing CHA-type zeolite of this embodiment, the content of alkali metals other than sodium calculated as MO (hereinafter also referred to as "MO content") relative to the metal content is preferably 0% by mass or more and 0.20% by mass or less, more preferably more than 0% by mass and 0.10% by mass or less, and even more preferably more than 0% by mass and 0.06% by mass or less.

[0074] For example, the composition of a CHA-type zeolite containing Na and K as alkali metal elements, and Ce, can be determined as follows.

[0075] CeO2 content [mass%] ={CeO2[g] / (SiO2+Al2O3+Na2O+K2O+CeO2[g])}×100 Na2O content [mass%] ={Na2O[g] / (SiO2+Al2O3+Na2O+K2O+CeO2[g])}×100 K2O content (M2O content) [mass%] ={K2O[g] / (SiO2+Al2O3+Na2O+K2O+CeO2[g])}×100 The cerium-containing CHA-type zeolite of this embodiment preferably has a residual acid content of 55% or more and 95% or less. With a residual acid content within this range, the zeolite can be expected to serve as a support for a nitrogen oxide reduction catalyst that exhibits high SCR catalytic performance. The residual acid content of the cerium-containing CHA-type zeolite of this embodiment is more preferably 55% or more and 90% or less, even more preferably 55% or more and 85% or less, and even more preferably 55% or more and 80% or less.

[0076] The cerium-containing CHA-type zeolite of this embodiment preferably has an average crystal diameter of 0.1 μm or more and 1.0 μm or less. Having an average crystal diameter of the above value is expected to improve handling properties, making it easier to coat the honeycomb uniformly. Furthermore, CHA-type zeolite having this average crystal diameter is expected to serve as a carrier that exhibits high SCR performance. The average crystal diameter of the cerium-containing CHA-type zeolite of this embodiment is more preferably 0.15 μm or more and 0.95 μm or less, and more preferably 0.20 μm or more and 0.80 μm or less. [Example]

[0077] The present disclosure will be described below with reference to examples, but the present disclosure is not limited thereto. (zeolite structure) The sample was subjected to XRD measurement using a powder X-ray diffractometer (device name: Ultima IV, manufactured by Rigaku Corporation) under the following measurement conditions.

[0078] Acceleration current / voltage: 40mA / 40kV Radiation source: CuKα radiation (λ=1.5405Å) Measurement mode: Continuous scan Scan condition: 40° / min Measurement range: 2θ=3° to 43° Divergence vertical limit slit: 10mm Divergence / entrance slit: 1° Receiving slit: open Receiving solar slit: 5° Detector: Semiconductor detector (D / teX Ultra) Filter: Ni filter The XRD pattern can be measured using a general powder X-ray diffractometer (Ultima IV, manufactured by Rigaku Corporation). The crystalline XRD peaks are those detected by identifying the 2θ of the peak top in the analysis of the XRD pattern using general analysis software (e.g., SmartLab Studio II, manufactured by Rigaku Corporation). The XRD pattern was analyzed under the following conditions.

[0079] Fitting conditions: Automatic, refine background Dispersive pseudo-Voigt function (peak shape) Background removal method: Fitting method Kα2 removal method: Kα1 / Kα2 ratio=0.497 Smoothing method: B-Spline curve Smoothing conditions: second-order differential method, σ cut value = 3, χ threshold = 1.5 (composition analysis) The composition of the sample was analyzed using a general inductively coupled plasma optical emission spectrometer (instrument name: OPTIMA7300DV, manufactured by PERKIN ELMER). The sample was dissolved in a mixed solution of hydrofluoric acid and nitric acid to prepare a measurement solution. The composition of the sample was analyzed using the obtained measurement solution. (average crystal size) SEM images of the samples were obtained using a standard scanning electron microscope (JSM-IT200, manufactured by JEOL). The average crystal size was calculated by measuring the diagonal of the smallest particle that could be observed independently, if the particle was rhombohedral or cubic, or the longest diameter if the particle was irregular, and then calculating the arithmetic mean of 50 ± 5 particles. However, secondary aggregates formed by aggregation of primary particles were not used in calculating the average crystal size, as they were not considered to be independent particles. (Residual acid amount rate) The residual acid amount ratio of the sample was calculated from the ratio of the Bronsted acid amount of the sample measured by the NH3-TPD method to the theoretical acid amount of the sample. (Bronsted acid site) The measurement of Bronsted acid sites was performed by the NH3-TPD method. Using a general temperature-programmed desorption analyzer (equipment name: BELCATII, manufactured by MicrotracBEL), the amount of Bronsted acid sites of the sample was measured. The measurement conditions are as follows. <Measured sample> Measured sample: 0.05 g <Pretreatment> Atmospheric gas type: Helium Gas flow rate: 50 ml / min Treatment temperature: 500 °C Treatment time: 60 minutes <NH3-TPD measurement> For the sample after pretreatment, at 100 °C, a mixed gas containing 1 vol% ammonia and 99 vol% helium gas was passed through the measured sample to saturate the measured sample with ammonia adsorption. After passing the mixed gas for 30 minutes, the mixed gas was replaced with helium gas, and helium gas was passed for 15 minutes to remove the residual ammonia in the atmosphere. After removing the residual ammonia, under a helium flow rate of 30 mL / min, the temperature was raised to 710 °C at a heating rate of 10 °C / min. Thereby, the ammonia adsorbed on the sample was desorbed from the sample. The ammonia desorbed from the sample was continuously quantified by a gas chromatograph equipped with a thermal conductivity detector (TCD), and thereby an ammonia desorption spectrum (TPD spectrum) was obtained.

[0080] The obtained TPD spectrum was analyzed by waveform separation using common analytical software (software name: Chem Master, Microtrac for Windows ver. 1.4.9, manufactured by MicrotracBEL). Baseline processing was performed with a base start of 100°C and a base end of 700°C. The baseline-processed spectrum was subjected to waveform decomposition using Gaussian distribution, dual waveform decomposition, and DFP. Of the two spectra obtained in this way, the area of ​​the spectrum with a peak top in the range of 300°C to 700°C was taken as the ammonia desorption spectrum. The area (integral value) of this spectrum was calculated and used as the amount of ammonia desorption. The amount of ammonia desorption (mmol) was divided by the weight (g) of the sample used in the measurement to determine the number of Brønsted acid sites of the sample. (Theoretical acid amount) The theoretical acid amount (mmol / g) of the sample was calculated using the above formula (1) as the theoretical value of the molar amount of Al per mass (Al-zeo:mmol / g) calculated from the composition of the sample.

[0081] Example 1 A 50 mass% aqueous solution of dimethylethylcyclohexylammonium bromide (DMECHABr), a 25 mass% aqueous solution of N,N,N-trimethyl-1-adamantanammonium hydroxide (TMAdOH), a 48 mass% aqueous solution of sodium hydroxide, a 48 mass% aqueous solution of potassium hydroxide, cerium (III) nitrate hexahydrate, pure water, and amorphous aluminosilicate (SiO2 / Al2O3 ratio: 14.0) were mixed together to a total amount of 60 g to obtain a raw material composition having the following molar composition.

[0082] SiO2 / Al2O3 ratio: 14.0 DMECH + / SiO2 ratio: 0.07 TMAda + / SiO2 ratio: 0.01 Add-SDA + / TACH + Ratio: 0.14 Na / SiO2 ratio: 0.14 K / SiO2 ratio: 0.06 Ce / SiO2 ratio: 0.0066 H2O / SiO2 ratio: 15 OH / SiO2 ratio: 0.21 The obtained raw material composition and seed crystal CHA-type zeolite (SSZ-13, SiO2 / Al2O3 ratio: 25) were mixed so that the amount was 1.0 mass% relative to the total amount of Si (calculated as SiO2) and Al (calculated as Al2O3) in the raw material composition, and then this was filled into an 80 ml sealed container and hydrothermally treated at 160 ° C for 48 hours under a rotation of 55 rpm to obtain a crystallized product. The obtained crystallized product was recovered by solid-liquid separation, washed with pure water in an amount 1 mass times the total amount of the raw material composition, and then dried in air at 110 ° C for 4 hours. The dried crystallized product was calcined in an air atmosphere at 600 ° C for 4 hours to obtain a calcined product.

[0083] The obtained fired product had an SiO2 / Al2O3 ratio of 14.1, a Na2O content of 1.56 mass%, a K2O content (M2O content) of 2.98 mass%, and a CeO2 content of 1.48 mass%, and was a cerium-containing CHA-type zeolite (hereinafter also referred to as "cerium-containing CHA-type zeolite") consisting of a single phase CHA structure.

[0084] Ion exchange was performed by mixing 10 g of the cerium-containing CHA-type zeolite with an ammonium chloride aqueous solution with an ammonium chloride concentration of 20% by mass. The amount of ammonium chloride aqueous solution used for ion exchange was 3.5 times the mass of the cerium-containing CHA-type zeolite. The cerium-containing CHA-type zeolite after ion exchange was washed with pure water in an amount 10 times the mass of the cerium-containing CHA-type zeolite and dried overnight at 110°C in an air atmosphere to obtain the cerium-containing CHA-type zeolite of this example. The cerium-containing CHA-type zeolite of this example (cation type is ammonium type) had a SiO2 / Al2O3 ratio of 14.8, a Na2O content below the detection limit (less than 0.01% by mass), a K2O content (MO content) of 0.02% by mass, a CeO2 content of 1.58% by mass, and a residual acid rate of 61.9%.

[0085] An SEM image of the cerium-containing CHA-type zeolite of this example is shown in Figure 1. The cerium-containing CHA-type zeolite of this example was composed of aggregated particles formed by aggregation of cubic primary particles. The crystalline particle size of the cerium-containing CHA-type zeolite of this example was 0.66 μm.

[0086] Example 2 A raw material composition having the following molar composition was obtained by mixing a 50 mass% DMECHABr aqueous solution, a 35 mass% DMECHAOH aqueous solution, a 48 mass% sodium hydroxide aqueous solution, a 48 mass% potassium hydroxide aqueous solution, cerium (III) nitrate hexahydrate, pure water, and amorphous aluminosilicate (SiO2 / Al2O3 ratio: 20.0).

[0087] SiO2 / Al2O3 ratio: 20.0 DMECH + / SiO2 ratio: 0.08 (Add-SDA + / TACH + ratio:0.00) Na / SiO2 ratio: 0.08 K / SiO2 ratio: 0.08 Ce / SiO2 ratio: 0.0029 H2O / SiO2 ratio: 18 OH / SiO2 ratio: 0.18 The obtained raw material composition and CHA-type zeolite (SSZ-13, SiO / AlO ratio: 25) as seed crystals were used in an amount of 1.0 mass% based on the total amount of Si (calculated as SiO) and Al (calculated as AlO) in the raw material composition, and were crystallized, washed, dried, and fired in the same manner as in Example 1. The fired product obtained was a cerium-containing CHA-type zeolite with an SiO / AlO ratio of 20.1, an NaO content of 0.35 mass%, a KO content of 1.91 mass%, and a CeO content of 0.65 mass%.

[0088] The cerium-containing CHA-type zeolite was subjected to ion exchange, washing, and drying to obtain the CHA-type zeolite of this example in the same manner as in Example 1. The CHA-type zeolite of this example had an SiO / AlO of 19.7, a NaO content below the lower detection limit (less than 0.01% by mass), a KO content (MO content) of 0.02% by mass, a CeO- content of 0.58% by mass, and a residual acid ratio of 72.0%.

[0089] An SEM image of the cerium-containing CHA-type zeolite of this example is shown in Figure 2. The cerium-containing CHA-type zeolite of this example was composed of aggregated particles formed by aggregation of cubic primary particles. The crystalline particle size of the cerium-containing CHA-type zeolite of this example was 0.67 μm.

[0090] Example 3 A raw material composition having the following molar composition was obtained by mixing a 35 mass % DMECHAOH aqueous solution, a 48 mass % sodium hydroxide aqueous solution, cerium (III) nitrate hexahydrate, water, and amorphous aluminosilicate (SiO2 / Al2O3 ratio: 10.6).

[0091] SiO2 / Al2O3 ratio: 10.6 DMECH + / SiO2 ratio: 0.08 Add-SDA + / TACH + Ratio:0.00 Na / SiO2 ratio: 0.27 K / SiO2 ratio: 0.00 Ce / SiO2 ratio: 0.0139 H2O / SiO2 ratio: 18 OH / SiO2 ratio: 0.35 The obtained raw material composition and CHA-type zeolite (SSZ-13, SiO / AlO ratio: 25) as seed crystals were crystallized, washed, dried, and fired in the same manner as in Example 1, except that 2.0 mass% of seed crystals were used relative to the total amount of Si converted into SiO and Al converted into AlO in the raw material composition, and the crystallization temperature was 165° C. The obtained fired product was a cerium-containing CHA-type zeolite with a SiO / AlO ratio of 10.5, a NaO content of 5.83 mass%, and a CeO content of 3.01 mass%.

[0092] The cerium-containing CHA-type zeolite was subjected to ion exchange, washing, and drying in the same manner as in Example 1 to obtain the cerium-containing CHA-type zeolite of this example. The CHA-type zeolite of this example had an SiO / AlO of 10.5, a NaO content of 0.01% by mass, a KO content (MO content) below the lower detection limit (less than 0.01% by mass), a CeO content of 2.89% by mass, and a residual acid rate of 63.5%.

[0093] An SEM image of the cerium-containing CHA-type zeolite of this example is shown in Figure 3. The cerium-containing CHA-type zeolite of this example was composed of aggregated particles formed by aggregation of cubic primary particles. The crystalline particle size of the cerium-containing CHA-type zeolite of this example was 0.50 μm.

[0094] Comparative Example 1 CHA-type zeolite was obtained based on the known SSZ-13 production method described in IZA (Internal Zeolite Association) (http: / / www.iza-online.org / synthesis / default.htm), except that the SiO2 / Al2O3 ratio was set to 15.0. That is, a 48 mass% sodium hydroxide aqueous solution, a 25 mass% TMAdaOH aqueous solution, aluminum hydroxide, fumed silica, and pure water were mixed to obtain a raw material composition having the following molar composition in a total amount of 60 g.

[0095] SiO2 / Al2O3 ratio: 15.0 DMECH + / SiO2 ratio: 0.00 TMAda + / SiO2 ratio: 0.20 Na / SiO2 ratio: 0.10 K / SiO2 ratio: 0.00 H2O / SiO2 ratio: 44 OH / SiO2 ratio: 0.30 The obtained raw material composition was mixed without adding seed crystals, and then packed into a sealed container and crystallized by hydrothermal treatment at 160°C for 96 hours under a rotation of 55 rpm. A calcined product was obtained in the same manner as in Example 1, except that the calcined product obtained was CHA-type zeolite with a SiO2 / Al2O3 ratio of 16.3 and a Na2O content of 1.97% by mass. The calcined product was subjected to ion exchange, washing, and drying in the same manner as in Example 1, to obtain CHA-type zeolite. The obtained CHA-type zeolite had a SiO2 / Al2O3 ratio of 16.6, a Na2O content of 0.01% by mass or less, and a residual acid rate of 55.8%.

[0096] 10 g of the CHA-type zeolite was contacted with an aqueous solution prepared by dissolving 0.437 g of cerium (III) nitrate hexahydrate in 5 g of pure water so that the CeO content was 1.50 mass%. Ce was incorporated by impregnation, and the resulting zeolite was then dried at 110°C in air. The CHA-type zeolite was then calcined in air at 550°C for 2 hours to obtain the cerium-containing CHA-type zeolite of this comparative example. The CHA-type zeolite of this comparative example had a SiO / AlO ratio of 16.6, a NaO content below the detection limit (less than 0.01 mass%), a KO content (M0 content) below the detection limit (less than 0.01 mass%), and a CeO content of 1.49 mass%. The residual acid content was 52.9%.

[0097] The SEM image of the CHA-type zeolite of this comparative example is shown in Figure 4. The cerium-containing CHA-type zeolite of this comparative example was composed of aggregated particles formed by aggregation of cubic primary particles. The cerium-containing CHA-type zeolite of this comparative example had a crystal particle size of 0.42 μm.

[0098] The measurement results for Examples and Comparative Examples are shown in the table below. In Comparative Example 1, which was produced using a general manufacturing method, the residual acid rate was 55.8% before cerium was added, but after cerium was added, it decreased to 52.9%. Compared to Comparative Example 1, Example 1 had a similar SiO2 / Al2O3 ratio and CeO2 content, but its residual acid rate exceeded 56.0%, indicating a high residual acid rate. Furthermore, Examples 2 and 3 showed that a cerium-containing CHA-type zeolite with a SiO2 / Al2O3 ratio of 3 or more and 30 or less has a high residual acid rate.

[0099] [Table 1]

Claims

1. A method for producing CHA-type zeolite includes a crystallization step of crystallizing a composition containing an N,N,N-trialkylcyclohexylammonium cation source, an alumina source, a silica source, a sodium source, a cerium source, and water, wherein the molar ratio of silica to alumina is 30 or less, to obtain a crystallized product; a calcination step of calcining the crystallized product at 400°C or higher and 700°C or lower to obtain a calcined product; and an alkali removal step of contacting the calcined product with an ammonium salt-containing solution.

2. The method for producing CHA-type zeolite according to claim 1, wherein the composition has at least the following molar composition: SiO ２ / Al ２ O ３ Ratio: 3 or more but less than 30 TACH ＋ / SiO ２ Ratio: 0.01 or more, 0.5 or less Na / SiO ２ Ratio: 0 over 0.60 or less Ce / SiO ２ Ratio: 0 over 0.05 or less H ２ O / SiO ２ Ratio: 3 or more but less than 50 OH / SiO ２ Ratio: 0.10 or more and 1.50 or less, except for TACH ＋ represents an N,N,N-trialkylcyclohexylammonium cation.

3. The method for producing CHA-type zeolite according to claim 1 or 2, wherein the composition contains one or more selected from the group consisting of an N,N,N-trialkyladamantanammonium cation source, a trimethylbenzylammonium cation source, and a tetraethylammonium cation source.

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