MFI zeolite and method for producing the same

Abstract

To provide at least one of: an MFI zeolite that has an excellent handling property when used as a zeolite slurry and has high adsorption performance to organic compounds without requiring use of a dispersant or pulverization; a method for producing the same; and an adsorbent containing the same.SOLUTION: An MFI zeolite is provided which has a D50 in the cumulative volume particle size distribution of 0.5 μm to 5.0 μm inclusive, and a peak height of the (020) plane relative to a peak height of the (101) plane in the powder X-ray diffraction pattern of 65% to 95% inclusive.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present disclosure relates to an MFI zeolite and a method for producing the same. [Background technology]

[0002] MFI zeolite is used in various industrial fields as an adsorbent for organic compounds. In general, when using MFI zeolite as an adsorbent, it is preferable to reduce the primary particle size and increase the specific surface area in order to increase the adsorption efficiency. For example, Patent Document 1 discloses a pentasil zeolite with a primary particle size of about 1 μm obtained by using normal propylamine as a structure directing agent as an MFI zeolite suitable as an adsorbent.

[0003] On the other hand, when the primary particle size is about 5 μm or less, the primary particles tend to aggregate with each other and form coarse secondary particles, which results in a high viscosity when made into a zeolite slurry, and poor handling properties.

[0004] Known methods for reducing the particle size of zeolite particles, particularly secondary particles, contained in a slurry include adding a dispersant such as an organic substance to the zeolite slurry (for example, Patent Document 2) and pulverizing the zeolite powder. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-11422 [Patent Document 2] JP2004-67976A Summary of the Invention [Problem to be solved by the invention]

[0006] In the MFI zeolite disclosed in Patent Document 1, primary particles are significantly aggregated to form coarse particles, and therefore it was not possible to obtain MFI zeolite having a small average particle size as a powder.

[0007] On the other hand, the method of adding a dispersant disclosed in Patent Document 2 is not preferred because the dispersant affects the adsorption characteristics of MFI zeolite.

[0008] There is also a method of reducing the particle size by crushing MFI zeolite, but with crushing, the crystallinity of the zeolite decreases as the particle size decreases, and therefore the adsorption performance decreases.

[0009] An object of the present disclosure is to provide at least one of an MFI zeolite that has a small average particle size and high adsorption performance for organic compounds without requiring the use of a dispersant or pulverization, a method for producing the same, and an adsorbent containing the same. [Means for solving the problem]

[0010] In the present disclosure, a method for producing MFI zeolite that is easy to handle when made into a zeolite slurry without using pulverization or a dispersant was investigated. As a result, it was found that by manipulating the pressure in a closed vessel in the process of crystallizing the raw material, it is possible to directly crystallize MFI zeolite that has a small average particle size and high adsorption performance for organic compounds, which could not be obtained by conventional production methods.

[0011] That is, the present invention is as described in the claims, and the gist of the present disclosure is as follows. [1] An MFI zeolite having a cumulative volume particle size distribution D50 of 0.5 μm or more and 5.0 μm or less, and a powder X-ray diffraction pattern in which the peak height of the (020) plane relative to the peak height of the (101) plane is 65% or more and 95% or less. [2] The MFI zeolite according to [1] above, wherein the molar ratio of silica to alumina is 50 or more and 3,000 or less. [3] The MFI zeolite according to any one of [1] and [2] above, wherein the frequency volume particle size distribution curve is a monomodal type. [4] The MFI zeolite according to any one of [1] to [3] above, having a standard deviation in volume particle size distribution of 10 μm or less. [5] The MFI zeolite according to any one of [1] to [4] above, having an average crystal size of 0.1 μm or more and 5.0 μm or less. [6] BET specific surface area is 300m 2 / g or more. [7] A method for producing the MFI zeolite according to any one of [1] to [6] above, comprising a step of hydrothermally treating a composition containing a silica source, an alumina source, an alkali source, normal butylamine, and water at 100°C or more and 150°C or less and 0.15 MPa or more, and then hydrothermally treating the composition at 100°C or more and 150°C or less while reducing the pressure at a reduction rate of 0.10 MPa / hour or more. Effect of the Invention

[0012] According to the present disclosure, it is possible to provide at least one of an MFI zeolite that has excellent handleability when made into a zeolite slurry and high adsorption performance for organic compounds, without requiring a method of adding a dispersant or a method of pulverizing zeolite powder, and a method for producing the same. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, the MFI zeolite of the present disclosure will be described with reference to an example of the embodiment. In the present disclosure, the configurations and parameters disclosed in the present specification include any combination, and the upper and lower limits of the values ​​disclosed in the present specification include any combination. The terms in this embodiment are as follows.

[0014] An "aluminosilicate" is a composite oxide having a structure consisting of a repeating network of aluminum (Al) and silicon (Si) via oxygen (O). 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".

[0015] In this embodiment, the XRD pattern can be obtained by XRD measurement under the following conditions.

[0016] Acceleration current / voltage: 40mA / 40kV Radiation source: CuKα radiation (λ=1.5405Å) Measurement mode: Continuous scan Scan condition: 10° / min Measurement range: 2θ=5° to 40° Divergence vertical limit slit: 10mm Divergence / entrance slit: 1° Scattering slit: open Receiving slit: Open Detector: Semiconductor detector (D / teX Ultra2) Filter: Not used The XRD pattern can be measured using a general powder X-ray diffractometer (for example, Ultima IV, manufactured by Rigaku Corporation). The crystalline XRD peak is a peak whose peak top 2θ is specified and detected in the analysis of the XRD pattern using general analysis software, and an example of the crystalline XRD peak is an XRD peak whose half-width is 2θ=0.10° or less.

[0017] "Zeolite" is a compound in which the skeleton atoms (hereinafter also referred to as "T atoms") have a regular structure with oxygen (O) interposed therebetween, and the T atoms are at least one of metal atoms and metalloid atoms. The metal atoms include at least one selected from the group consisting of aluminum (Al), titanium (Ti), iron (Fe), zinc (Zn), gallium (Ga) and tin (Sn), with aluminum being preferred. The metalloid atoms include at least one selected from the group consisting of boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb) and tellurium (Te), with silicon being preferred.

[0018] A "zeolite-like substance" is a compound having a regular structure in which T atoms are oxygen-mediated, and the T atoms contain at least an atom other than a metal or a metalloid. Examples of zeolite-like substances include complex phosphorus compounds containing phosphorus (P) as the T atom, such as aluminophosphate (AlPO) and silicoaluminophosphate (SAPO).

[0019] The "skeletal structure" of zeolite or zeolite-like substances (hereinafter also referred to as "zeolite structure") is a skeletal structure specified by the skeletal structure code (hereinafter also referred to simply as "structure code") defined by the Structure Commission of the International Zeolite Association. For example, the MFI structure is a skeletal structure specified by the structure code "MFI". The MFI structure can be identified by comparing it with the XRD pattern (hereinafter also referred to as "reference pattern") described in the MFI of Zeolite Framework Types on the IZA Structure Commission's homepage http: / / www.iza-structure.org / databases / . With regard to the zeolite structure, the skeletal structure, the crystal structure, and the crystal phase are each used synonymously.

[0020] In the present embodiment, "-type zeolite" such as "MFI type zeolite" means a zeolite having a zeolite structure of the structure code, and preferably means a crystalline aluminosilicate having a zeolite structure of the structure code. A zeolite having a zeolite structure of the structure code "MFI" may be one having an XRD peak in its XRD pattern that is identified as an MFI type zeolite structure, and preferably one having at least an XRD peak that can be identified as an MFI type zeolite structure.

[0021] Each peak in the XRD pattern of MFI zeolite can be assigned to a lattice plane (hkl), (h, k, and l are integers), by comparison with a reference pattern.

[0022] The "average crystal size" is the average particle size of primary particles, and the primary particles are the smallest unit particles that can be observed independently in scanning electron microscope (hereinafter also referred to as "SEM") observation under the following conditions. SEM observation can be performed using a general scanning electron microscope (for example, device name: JSM-IT200, manufactured by JEOL Ltd.).

[0023] Acceleration voltage: 6kV Magnification: 10,000±5,000x The average crystal size is determined by first extracting 100±10 primary particles whose contours are observed without interruption in the SEM observation image, measuring the longest diameter of each extracted primary particle, and calculating the average value, which is the average crystal size. The number of SEM observation images may be any number that allows the above-mentioned number of primary particles to be observed, and one or more SEM observation images may be used.

[0024] "D10", "D50" and "D90" are the particle diameters [μm] when the cumulative amount of the particle diameter frequency in the cumulative volume particle size distribution is 10%, the particle diameters [μm] when the cumulative amount of the particle diameter frequency is 50%, and the particle diameters [μm] when the cumulative amount of the particle diameter frequency is 90%, respectively. Note that D50 is used interchangeably with "median diameter".

[0025] The cumulative and frequency volume particle size distributions of MFI type zeolite, as well as D10, D50 and D90, may be measured under the following conditions using a general laser diffraction / scattering type particle size distribution measuring device (for example, device name: Microtrac MT3300EXII, manufactured by Microtrac BEL Co., Ltd.).

[0026] Measurement range: 0.02~2000μm Particle refractive index: 1.66 Particle permeability: permeation Particle shape: non-spherical Solvent refractive index: 1.333 The "solid content concentration" refers to the mass ratio of zeolite in the slurry, and is a concentration calculated by the following formula.

[0027] Solid content concentration [mass%] = (Zeolite mass [g] / Slurry mass [g]) × 100 The slurry mass in the above formula is a value obtained by measuring the mass of the slurry, and the zeolite mass is a value measured by measuring the mass of the zeolite after drying the slurry after measuring the mass of the slurry to obtain a solid content, and treating the solid content in air at 600°C for 1 hour.

[0028] Hereinafter, the MFI zeolite of this embodiment will be described.

[0029] The MFI zeolite of this embodiment has a D50 of 0.5 μm or more and 5.0 μm or less, and in the powder X-ray diffraction pattern, the peak height of the (020) plane relative to the peak height of the (101) plane (hereinafter also referred to as the "(020) / (101) peak ratio") is 65% or more and 95% or less.

[0030] The MFI zeolite of this embodiment has a D50 of 0.5 μm or more and 5.0 μm or less. When the MFI zeolite has a D50 of less than 0.5 μm, the viscosity of the MFI zeolite when made into a slurry is high, and the handleability (operability) is significantly low. When the D50 exceeds 5.0 μm, the viscosity of the slurry at a high shear rate is likely to increase, and the fluidity is reduced. The D50 of the MFI zeolite of this embodiment is 1.0 μm or more or 1.5 μm or more, and can be 3.0 μm or less, and is preferably 1.0 μm or more and 3.0 μm or less, and more preferably 1.5 μm or more and 3.0 μm or less.

[0031] The MFI zeolite of the present embodiment preferably has a frequency volume particle size distribution curve of a monomodal type. In the present embodiment, the frequency volume particle size distribution curve of a monomodal type is a frequency volume particle size distribution curve having a distribution shape with one peak, in other words, the frequency volume particle size distribution curve obtained by measuring the cumulative volume particle size distribution is a curve having a shape with one peak, preferably, the frequency volume particle size distribution curve is a curve having a shape with one inflection point of the particle diameter frequency in the frequency volume particle size distribution curve.

[0032] The MFI zeolite of this embodiment preferably has a standard deviation in its volumetric particle size distribution (hereinafter also simply referred to as "standard deviation") of 10 μm or less. The standard deviation of the MFI zeolite of this embodiment may be 7 μm or less or 5 μm or less, and may also be greater than 0 μm or greater than 0.5 μm, preferably greater than 0 μm and less than 7 μm, and more preferably 0.5 μm or more and less than 5 μm. If the standard deviation satisfies this range, when the MFI zeolite of this embodiment is made into a slurry, the viscosity of the resulting slurry is less likely to increase.

[0033] The "standard deviation" in this embodiment is a value obtained by dividing the difference between D90 and D10 in the cumulative volume particle size distribution by 2, and can be calculated by the following formula.

[0034] Standard deviation [μm]=(D90[μm]-D10[μm]) / 2 The MFI zeolite of this embodiment has a (020) / (101) peak ratio in its XRD pattern of 65% or more and 95% or less. If the (020) / (101) peak ratio is outside the above range, the amount of organic compounds adsorbed will be small. If MFI zeolite is subjected to an operation that applies strong stress to the particles, such as crushing, the (020) / (101) peak ratio tends to be high. This is thought to be due to a decrease in the crystallinity of the MFI zeolite, and as a result, the amount of organic compounds adsorbed will tend to be small. From the above points, the (020) / (101) peak ratio of the MFI zeolite of this embodiment is 70% or more or 75% or more, and can be 85% or less, preferably 70% or more and 85% or less, and more preferably 75% or more and 85% or less.

[0035] In the MFI zeolite of the present embodiment, the peak height of the (101) plane relative to the peak height of the (501) plane in the XRD pattern (hereinafter also referred to as the "(101) / (501) peak ratio") is preferably 50% or more and 140% or less. The (101) / (501) peak ratio is considered to be a value due to the 10-membered oxygen ring in the framework structure of the MFI zeolite, and the numerical value tends to be high when the structure directing agent (hereinafter also referred to as "SDA") and the alkali metal element in the 10-membered oxygen ring are removed by the structure directing agent removal step and the cation exchange step described later. Since the amount of adsorption of organic compounds at an equilibrium pressure of 0.01 kPa or more is likely to be improved, the (101) / (501) peak ratio of the MFI zeolite of the present embodiment is 80% or more or 90% or more, and 140% or less or 110% or less, and is preferably 80% or more and 140% or less, and more preferably 90% or more and 110% or less.

[0036] In this embodiment, the "(101) plane peak" refers to an XRD peak in the XRD pattern of MFI zeolite where the lattice spacing d is 11.10±0.50 Å, the "(020) plane peak" refers to an XRD peak in the XRD pattern of MFI zeolite where the lattice spacing d is 9.97±0.10 Å, and the "(501) plane peak" refers to an XRD peak in the XRD pattern of MFI zeolite where the lattice spacing d is 3.87±0.03 Å.

[0037] The XRD pattern does not indicate the crystal structure by each independent XRD peak itself, but by a single XRD pattern consisting of a group of multiple XRD peaks having specific relative intensities, the crystal structure of the MFI zeolite is indicated. A change in the lattice spacing and relative intensity of the XRD peaks means a change in the crystal structure. Therefore, the crystal structure of the MFI zeolite of this embodiment can be specified by the group of XRD peaks having these relative intensities. Therefore, the change in the crystal structure changes the lattice spacing and relative intensity of the multiple XRD peaks.

[0038] The MFI zeolite of the present embodiment has an XRD peak in its XRD pattern that is specified as an MFI structure, and preferably has an XRD pattern including at least the following XRD peaks:

[0039] [Table 1]

[0040] In this embodiment, the XRD pattern may include each of the XRD peaks in the above table, and may also include other XRD peaks that are assigned to the MFI structure.

[0041] It is more preferable that the MFI zeolite of the present embodiment contains at least the following XRD peaks in its XRD pattern.

[0042] [Table 2]

[0043] It is more preferable that the MFI zeolite of the present embodiment contains at least the following XRD peaks in its XRD pattern.

[0044] [Table 3]

[0045] The MFI zeolite of this embodiment may contain XRD peaks having a relative intensity of less than 1% in addition to the above peaks, but these low-intensity XRD peaks do not need to be taken into consideration for identifying the crystal structure.

[0046] The MFI zeolite of this embodiment preferably has a molar ratio of silica to alumina (hereinafter also referred to as "SiO2 / Al2O3 ratio") of 50 or more and 3000 or less. When the SiO2 / Al2O3 ratio is the above value, the adsorption performance for organic compounds is likely to be high. In terms of being likely to exhibit high adsorption characteristics for organic compounds even in the presence of water, the SiO2 / Al2O3 ratio of the MFI zeolite of this embodiment is preferably 100 or more and 3000 or less, more preferably 1000 or more and 3000 or less, and even more preferably 2000 or more and 3000 or less. On the other hand, in terms of being likely to increase the amount of adsorption of organic compounds, the SiO2 / Al2O3 ratio of the MFI zeolite of this embodiment is preferably 50 or more and 2000 or less, more preferably 100 or more and 1000 or less, and even more preferably 170 or more and 500 or less.

[0047] In the MFI zeolite of this embodiment, in order to facilitate an improvement in the adsorption amount of organic compounds, the ratio of the alkali metal content (hereinafter also referred to as the "alkali metal content") to the total content (hereinafter also referred to as the "metal content") of the silicon (Si) content, the aluminum (Al) content, and the alkali metal (M) content of the MFI zeolite can be 0 mass% or more or more than 0 mass%, and can be 0.5 mass% or less or 0.1 mass% or less, preferably 0 mass% or more and 0.5 mass% or less, more preferably more than 0 mass% and 0.1 mass% or less, and even more preferably 0 mass% or more and 0.05 mass% or less.

[0048] When the MFI zeolite contains two or more kinds of alkali metal elements, the alkali metal content may be the total value of the contents of the respective metal elements. For example, when the alkali metal elements contain sodium (Na) and potassium (K), the alkali metal content may be the ratio of the total content of sodium and potassium to the metal content of the MFI zeolite (hereinafter, also referred to as "(Na+K) content"), which may be calculated as follows.

[0049] (Na+K) content [mass%] ={(Na+K)[g] / (Si+Al+Na+K)[g]}×100 The SiO2 / Al2O3 ratio and the alkali metal content can be determined from the measured values ​​of Si, Al, and M by preparing a sample solution by dissolving MFI zeolite in a mixed aqueous solution of hydrofluoric acid and nitric acid, and measuring the sample solution by inductively coupled plasma atomic emission spectrometry (ICP-AES) using a general ICP device (for example, device name: OPTIMA5300DV, manufactured by PerkinElmer).

[0050] The MFI zeolite of the present embodiment may contain SDA to the extent that it does not affect the adsorption performance for organic compounds. For example, when the mass (weighed value) of the entire MFI zeolite including SDA is taken as 100 mass%, the mass ratio of SDA contained in the MFI zeolite (hereinafter also referred to as "SDA content") may be 0 mass% or more and less than 6.0 mass%.

[0051] The average crystal diameter of the MFI-type zeolite of this embodiment is 0.1 μm or more, 0.5 μm or more, or 1.0 μm or more, and may be 5.0 μm or less, 3.0 μm or less, or 1.5 μm or less. It is preferably 0.1 μm or more and 5.0 μm or less, more preferably 0.5 μm or more and 3.0 μm or less, and even more preferably 1.0 μm or more and 1.5 μm or less. When the MFI-type zeolite of this embodiment is in the form of a slurry, the average crystal diameter being the above value makes it likely to exhibit a low viscosity regardless of the shear rate.

[0052] Note that the average crystal diameter is the average diameter of the primary particles of the MFI-type zeolite, which is different from the average diameter of secondary particles including aggregated particles such as D10, D50, and D90. Also, when the frequency volume particle size distribution curve shows a unimodal volume particle size distribution, the average crystal diameter is likely to be larger than D10 and smaller than D90. The MFI-type zeolite of this embodiment preferably satisfies D10 < average crystal diameter < D90 (unit: μm), more preferably the frequency volume particle size distribution curve shows a unimodal volume particle size distribution and further satisfies D10 < average crystal diameter < D90 (unit: μm).

[0053] The MFI-type zeolite of this embodiment preferably has a BET specific surface area of 300 m 2 / g or more.

[0054] Since the adsorption amount of the organic compound is likely to increase, the BET specific surface area of the MFI-type zeolite of this embodiment is 330 m 2 / g or more, or 350 m 2 / g or more, and may be 800 m 2 / g or less, or 500 m 2 / g or less. It is preferably 330 m 2 / g or more and 800 m 2 / g or less, and more preferably 350 m 2 / g or more and 500 m 2 / g or less.

[0055] The BET specific surface area can be determined by measurements in accordance with JIS Z 8830:2013. That is, a general automatic specific surface area measuring device (for example, device name: BELSORP-miniII, manufactured by Microtrack BEL Co., Ltd.) and nitrogen as the adsorption gas are used to measure the BET specific surface area of ​​the measurement sample by the single-point method. As a pretreatment, the measurement sample is kept in a vacuum atmosphere (10 Pa or less) at 350 ± 50 °C for 1 hour to 5 hours.

[0056] The MFI zeolite of the present embodiment has high crystallinity compared to conventional MFI zeolite after crystallization, but has a low viscosity when made into a slurry. For example, when the MFI zeolite of the present embodiment is made into a slurry having a solid content concentration of 51 mass% using pure water as a solvent, the viscosity of the slurry is low at a shear rate of 1100 s -1 The viscosity at a shear rate of 1100 s is preferably 50 mPa s or less, 30 mPa s or less, or even 20 mPa s or less. -1 If the viscosity at 200° C. is 1 mPa·s or more, and even 3 mPa·s or more, the adsorbent will have a fluidity suitable for application to a carrier.

[0057] In this embodiment, the shear rate is 1100 s -1 The viscosity of the sample can be measured by using a general viscometer (for example, MCR 92, manufactured by Anton Paar) in the following manner. MFI type zeolite is mixed with pure water to prepare a zeolite slurry with a solid content concentration of 51% by mass, which is used as the sample slurry. 2 mL of the sample slurry is dropped onto the stage of the measurement device equipped with a parallel plate type measurement jig (PP50), and the sample is subjected to a shear rate of 1100 s -1 During the measurement, the stage temperature is set to 20°C, and the gap between the measuring tool and the stage is set to 0.2 mm.

[0058] In the MFI zeolite of this embodiment, the amount of toluene adsorption relative to the mass of the zeolite at an equilibrium pressure of 0.005 kPa (hereinafter also referred to as "toluene adsorption amount") is preferably 5.0 mass% or more, more preferably 5.5 mass% or more, and even more preferably 6.0 mass% or more. In addition, the amount of toluene adsorption at an equilibrium pressure of 0.01 kPa is preferably 5.0 mass% or more, more preferably 6.0 mass% or more, and even more preferably 7.0 mass% or more. In addition, the amount of toluene adsorption at an equilibrium pressure of 0.1 kPa is preferably 6.0 mass% or more, more preferably 7.0 mass% or more, and even more preferably 8.0 mass% or more. In addition, the amount of toluene adsorption at an equilibrium pressure of 1 kPa is preferably 8.0 mass% or more, more preferably 8.5 mass% or more, and even more preferably 9.0 mass% or more. The higher the toluene adsorption amount at each equilibrium pressure, the more preferable, but the upper limit of the physical amount of toluene adsorption is 25.0 mass% or less or 20.0 mass% or less. Furthermore, it is preferable that the toluene adsorption power at equilibrium pressures of 0.005 kPa, 0.01 kPa, 0.1 kPa and 1 kPa all satisfy the above-mentioned value.

[0059] The amount of toluene adsorption can be measured by the following method using a general vapor adsorption measuring device (for example, device name: BELSORP-maxII, manufactured by Microtrack Bell Co., Ltd.). 3 The sample tube is filled with 20±10 mg of MFI zeolite and held in a vacuum atmosphere (10 Pa or less) at 350±50°C for 1 hour to 5 hours to prepare a measurement sample. The sample tube filled with the measurement sample is then set in a vapor adsorption measurement device, and the equilibrium pressure is changed from 0.001 to 1 kPa at 25°C to measure the toluene adsorption amounts [mass %] at 0.005 kPa, 0.01 kPa, 0.1 kPa and 1 kPa.

[0060] The MFI zeolite of this embodiment is preferably an aluminosilicate, and more preferably a crystalline aluminosilicate. Therefore, the MFI zeolite of this embodiment preferably does not contain phosphorus, and more preferably does not contain phosphorus (P) as a T atom. The phosphorus content of the MFI zeolite of this embodiment is preferably 100 mass ppm or less or 1 mass ppm or less, and is preferably 0 mass ppm or more or more than 0 mass ppm, and examples thereof include 0 mass ppm or more and 100 mass ppm or less, 0 mass ppm or more and 1 mass ppm or less, and further more than 0 mass ppm and 1 mass ppm or less.

[0061] Next, a method for producing the MFI zeolite of this embodiment will be described.

[0062] The method for producing the MFI zeolite of this embodiment includes a step of hydrothermally treating a composition containing a silica source, an alumina source, an alkali source, normal butylamine, and water (hereinafter also referred to as the "raw material composition") at 100°C to 150°C and 0.15 MPa or more, and then hydrothermally treating the composition at 100°C to 150°C while reducing the pressure at a reduction rate of 0.10 MPa / hour or more (hereinafter also referred to as the "crystallization step"). The crystallization step allows the MFI zeolite of this embodiment to be obtained as a crystallized product from the raw material composition.

[0063] The silica source is at least one of a silicon-containing compound and silicon (Si), and examples thereof include one or more selected from the group consisting of silica sol, fumed silica, colloidal silica, precipitated silica, sodium silicate, potassium silicate, amorphous silicic acid, crystalline aluminosilicate, and amorphous aluminosilicate. From the viewpoint of preventing the D50 of the crystallized MFI zeolite from becoming coarse, the silica source is preferably at least one of amorphous silicic acid and amorphous aluminosilicate, and more preferably amorphous aluminosilicate.

[0064] The alumina source is an aluminum compound, and is, for example, one or more selected from the group consisting of aluminum hydroxide, aluminum oxide, aluminum sulfate, sodium aluminate, aluminum chloride, and amorphous aluminosilicate. From the viewpoint of preventing the D50 of the crystallized MFI zeolite from becoming coarse, the alumina source is preferably one or more selected from the group consisting of aluminum oxide, aluminum sulfate, sodium aluminate, and amorphous aluminosilicate, and from the viewpoint of reactivity, it is more preferably at least one of aluminum sulfate and amorphous aluminosilicate, and further preferably amorphous aluminosilicate.

[0065] Particularly preferred alumina and silica sources include at least one of amorphous silica, aluminum sulfate, and amorphous aluminosilicate, and amorphous aluminosilicate is preferred. The SiO2 / Al2O3 ratio of the amorphous aluminosilicate is 10 or more, 15 or more, or 20 or more, and 10000 or less, 1000 or less, or 80 or less, and is preferably 10 or more and 10000 or less, 15 or more and 1000 or less, or 20 or more and 80 or less.

[0066] In addition, when another starting material contained in the raw material composition contains aluminum, it may be used as the alumina source, and for example, when the silica source contains aluminum, the silica source can be considered to be the alumina source at the same time. An example of such a silica source is an amorphous aluminosilicate having an aluminum content of 0.001% by mass or more and 1.000% by mass or less, calculated as Al2O3, relative to the mass of the entire silica source.

[0067] The alkali source is at least one of a compound containing an alkali metal element and an alkali metal, and examples of the alkali source include one or more selected from the group consisting of hydroxides, carbonates, sulfates, chlorides, bromides, silicates, and iodides of alkali metals. One or more selected from the group consisting of hydroxides, chlorides, bromides, and iodides is preferred, and hydroxides are more preferred.

[0068] The alkali metal element may be one or more selected from the group consisting of sodium, potassium, rubidium and cesium, with at least one of sodium and potassium being preferred, and sodium being more preferred.

[0069] The raw material composition contains normal butylamine (hereinafter also referred to as "NBA"). This makes it difficult for the D50 of the crystallized MFI zeolite to become coarse, and makes it easy to obtain MFI zeolite having high adsorption performance for organic compounds. The raw material composition only needs to contain NBA as an SDA source, and it is preferable that the SDA source is only NBA. However, in addition to NBA, it may contain an SDA source that directs the MFI structure. Examples of SDA sources other than NBA include one or more amines selected from the group consisting of di-normal butylamine, tributylamine, di-normal propylamine, tripropylamine, dipropylenetriamine, dihexamethylenetriamine, triethylenetetramine, diethylenetriamine, ethanolamine, and propanolamine, at least one quaternary ammonium cation of tetrapropylammonium and tetraethylammonium, and one or more selected from the group consisting of glycerol, alcohols, and morpholine.

[0070] The water may be at least one selected from the group consisting of distilled water, deionized water, and pure water. Furthermore, water derived from other starting materials contained in the raw material composition, such as solvents and water-containing compounds, is also considered to be water in the raw material composition.

[0071] The raw material composition does not need to contain seed crystals in terms of reducing raw material costs; however, the raw material composition may contain a sufficiently small amount of seed crystals relative to the silica source and the alumina source in order to reduce the processing time required for crystallization.

[0072] The seed crystals are preferably MFI zeolite, and the SiO2 / Al2O3 ratio of the MFI zeolite is preferably 10 or more and 4,000 or less.

[0073] The seed crystals contained in the raw material composition have a ratio of the total mass of aluminum and silicon in the seed crystals, calculated as Al2O3 and SiO2, respectively, to the total mass of aluminum and silicon in the raw material composition (not including the seed crystals), calculated as Al2O3 and SiO2, respectively (hereinafter also referred to as "seed crystal content") of 0 mass% or more or 1 mass% or more and 20 mass% or less or 10 mass% or less. Preferred seed crystal contents can be, for example, 0 mass% or more and 20 mass% or less, more than 0 mass% and 20 mass% or less, or 1 mass% or more and 1 mass% or less.

[0074] The preferred composition of the raw material composition is the following molar composition.

[0075] SiO2 / Al2O3 ratio = 50 or more, 200 or more, or 1000 or more, and 1500 or less, 3000 or less, or 5000 or less NBA / SiO2 ratio = 0.01 or more, 0.05 or more, 0.10 or more, and 0.30 or less, 0.50 or less, 0.70 or less M / SiO2 ratio = 0.01 or more, 0.05 or more, or 0.10 or more, and 0.20 or less, 0.40 or less, or 0.60 or less OH / SiO2 ratio = 0.01 or more, 0.05 or more, or 0.10 or more, and 0.20 or less, 0.40 or less, or 0.60 or less H2O / SiO2 ratio = 2 or more, 6 or more, 8 or more, and 100 or less, 50 or less, 20 or less Here, M represents an alkali metal element. When there are two or more alkali metal elements, M may be the total value of each metal element. For example, when the alkali metal element M includes sodium (Na) and potassium (K), M may be expressed as M: (Na+K).

[0076] Particularly preferred compositions of the raw material composition include the following molar compositions.

[0077] SiO2 / Al2O3 ratio = 100 or more and 5000 or less Preferably between 200 and 4500 More preferably, 1000 to 4500 NBA / SiO2 ratio = 0.05 or more and 0.30 or less Preferably, 0.10 or more and 0.30 or less M / SiO2 ratio = 0.01 or more and 0.30 or less Preferably, 0.05 or more and 0.20 or less OH / SiO2 ratio = 0.01 or more and 0.30 or less, Preferably, 0.05 or more and 0.20 or less H2O / SiO2 ratio =5 or more and 50 or less, Preferably 8 to 15 In this embodiment, the raw material composition preferably does not contain fluorine (F) and fluorine-containing compounds (hereinafter also referred to as "fluorine, etc."). Fluorine, etc. are particularly highly corrosive, and a manufacturing method using them requires special manufacturing equipment that exhibits corrosion resistance. This tends to increase manufacturing costs. Therefore, the raw material composition preferably does not contain fluorine. The fluorine content of the raw material composition is preferably 100 mass ppm or less or 1 mass ppm or less, and is preferably 0 mass ppm or more or more than 0 mass ppm, and examples thereof include 0 mass ppm or more and 100 mass ppm or less, 0 mass ppm or more and 1 mass ppm or less, and further more than 0 mass ppm and 1 mass ppm or less.

[0078] In the crystallization step, the raw material composition is subjected to a hydrothermal treatment at 100° C. to 150° C. and at 0.15 MPa or more, whereby the raw material composition is crystallized.

[0079] If the hydrothermal treatment temperature is less than 100°C, the time required for crystallization of the raw material composition becomes very long. On the other hand, if the temperature exceeds 150°C, the secondary particle size, especially D50, becomes too large. Therefore, the hydrothermal treatment temperature is 100°C or more and 150°C or less, and preferably 115°C or more and 150°C or less.

[0080] The pressure of the hydrothermal treatment is 0.15 MPa or more (hydrothermal treatment pressure). If the pressure is less than 0.15 MPa, the crystallinity of the resulting MFI zeolite is low, and the adsorption performance is low. The hydrothermal treatment pressure is preferably 0.15 MPa or more and 0.70 MPa or less, more preferably 0.20 MPa or more and 0.50 MPa or less.

[0081] In this embodiment, the pressure (hydrothermal treatment pressure) may be adjusted to the above-mentioned value, and examples of the pressure include one or more methods selected from the group consisting of autogenous pressure, a method of introducing or sucking in an atmospheric gas, and a method of compressing or expanding the volume of a sealed container filled with the raw material composition.

[0082] In this embodiment, the value of the pressure (hydrothermal treatment pressure) refers to the value of absolute pressure, which is expressed as the sum of atmospheric pressure and gauge pressure.

[0083] In the hydrothermal treatment, the raw material composition may be in a state of being stirred or left to stand, and is preferably in a state of being stirred. The stirring speed may be appropriately adjusted depending on the scale and structure of the apparatus used for crystallization, and may be, for example, 30 rpm to 500 rpm or 40 rpm to 400 rpm.

[0084] The time for the hydrothermal treatment may be adjusted depending on the amount of the raw material composition subjected to the hydrothermal treatment and the crystallization temperature. Examples of industrially applicable crystallization times are, for example, 5 hours or more or 10 hours or more, and 300 hours or less, 200 hours or less, or 100 hours or less, and examples thereof include 5 hours or more and 300 hours or less, or 10 hours or more and 50 hours or less.

[0085] The hydrothermal treatment in the crystallization step is carried out by filling the raw material composition in a sealed container. The sealed container may be any container that can seal the raw material composition and has sufficient durability against the pressure generated when the hydrothermal treatment is carried out.

[0086] In the crystallization step, the mixture is then subjected to hydrothermal treatment at 100°C to 150°C while reducing the pressure at a pressure reduction rate of 0.10 MPa / hour or more (hereinafter also referred to as "reduced pressure hydrothermal treatment"). This allows the MFI zeolite having the D50 of this embodiment to be directly crystallized from the raw material composition. The reason why the MFI zeolite having the D50 of this embodiment can be directly crystallized by performing hydrothermal treatment at the above pressure reduction rate and temperature has not been clarified, but it is believed that by reducing the pressure at a pressure reduction rate of 0.10 MPa / hour or more, the raw material composition in the sealed container rolls, suppressing the aggregation of the crystallized particles, and as a result, it is possible to directly crystallize the MFI zeolite having a D50 of 0.5 μm to 5.0 μm.

[0087] In the crystallization step, the temperature at which heat treatment is performed while reducing pressure (hereinafter also referred to as "reduced pressure hydrothermal treatment temperature") is set to 100°C or higher and 150°C or lower, thereby obtaining MFI zeolite having D50 of this embodiment. If the temperature is lower than 100°C, the primary particles of MFI zeolite tend to aggregate, and D50 becomes excessively large. The reduced pressure hydrothermal treatment temperature is 105°C or higher or 110°C or higher, and can be 140°C or lower or 130°C or lower, with 105°C or higher and 140°C or lower being preferred, and 110°C or higher and 130°C or lower being more preferred.

[0088] The decompression rate in the crystallization step is 0.10 MPa / hour or more. If the decompression rate is less than 0.10 MPa / hour, D50 tends to be large. The decompression rate is preferably 0.10 MPa / hour or more and 0.30 MPa / hour or less, more preferably 0.15 MPa / hour or more and 0.30 MPa / hour or less.

[0089] The pressure difference between the start and end of the reduced pressure hydrothermal treatment is preferably 0.03 MPa or more and 0.40 MPa or less, more preferably 0.10 MPa or more and 0.40 MPa or less, and even more preferably 0.10 MPa or more and 0.35 MPa or less, which tends to make D50 smaller and tends to improve the handleability of the slurry containing MFI zeolite.

[0090] The pressure at the start of the reduced pressure hydrothermal treatment is preferably 0.15 MPa or more and 0.70 MPa or less, and more preferably 0.20 MPa or more and 0.50 MPa or less.

[0091] After the start of reduced pressure hydrothermal treatment, the reduced pressure hydrothermal treatment may be terminated when the pressure indication is maintained at less than the indicated value ±5 kPa (0.005 MPa) for one hour or more (hereinafter also referred to as a "stable state"). The stable state may be maintained for one hour or more, and may be, for example, from one hour to 10 hours.

[0092] The production method of this embodiment may include, after the crystallization step, one or more steps selected from the group consisting of a washing step, a drying step, a structure-directing agent removal step, and a cation exchange step.

[0093] In the washing step, the zeolite and the liquid phase are separated into a solid-liquid phase by a known method, and the zeolite obtained as a solid phase may be washed with pure water.

[0094] In the drying step, moisture physically adsorbed on the zeolite is removed. The drying conditions are arbitrary, and examples of the drying method include leaving the zeolite in the air at 50° C. to 250° C. for 1 hour to 120 hours or drying with a spray dryer.

[0095] The structure-directing agent removal step removes SDA contained in the zeolite. Examples of methods for removing SDA include one or more methods selected from the group consisting of exchange treatment with resin, pyrolysis treatment, and calcination treatment. From the viewpoint of production efficiency, the structure-directing agent removal step is preferably at least one of pyrolysis treatment and calcination treatment. In the case of calcination treatment, the calcination conditions may be appropriately adjusted depending on the amount of zeolite to be treated, and examples of the calcination conditions include, for example, in air, at 400°C to 700°C for 1 hour to 24 hours.

[0096] The crystallized MFI zeolite may have alkali metal elements derived from the alkali source on its ion exchange sites. In the cation exchange process, these are replaced with ammonium cations. Thione (NH 4+ ) and protons (H+ For cation exchange with ammonium cations, the MFI zeolite is contacted with an aqueous ammonium chloride solution. For cation exchange with protons, the MFI zeolite is contacted with hydrochloric acid. EXAMPLES

[0097] The present disclosure will be described below with reference to examples, but the present disclosure is not limited to these examples. (Identification of crystalline phase) An XRD pattern was obtained using a powder X-ray diffractometer (device name: Ultima IV, manufactured by Rigaku Corporation) under the following conditions.

[0098] Acceleration current / voltage: 40mA / 40kV Radiation source: CuKα radiation (λ=1.5405Å) Measurement mode: Continuous scan Scan condition: 10° / min Measurement range: 2θ=5° to 40° Divergence vertical limit slit: 10mm Divergence / entrance slit: 1° Scattering slit: open Receiving slit: Open Detector: Semiconductor detector (D / teX Ultra2) Filter: Not used The crystalline phase of the sample was identified by comparing the obtained XRD pattern with the XRD pattern listed in the MFI of Zeolite Framework Types on the IZA Structure Committee homepage http: / / www.iza-structure.org / databases / . (Volumetric particle size distribution) The volumetric particle size distribution was determined by measuring the frequency curve and the cumulative curve of the volumetric particle size distribution using a laser diffraction / scattering particle size distribution analyzer (device name: Microtrac MT3300EXII, manufactured by Microtrac Bell Co., Ltd.). The measurement conditions are as follows:

[0099] Measurement range: 0.02~2000μm Particle refractive index: 1.66 Particle permeability: permeation Particle shape: non-spherical Solvent refractive index: 1.333 Ultrasonic pretreatment: None From the obtained cumulative volume particle size distribution, D10, D50 and D90 were obtained. From the obtained D10, D50 and D90 values, the standard deviation was calculated using the following formula.

[0100] Standard deviation [μm]=(D90[μm]-D10[μm]) / 2 The shape of the frequency volume particle size distribution curve was also confirmed. (Average crystal size) SEM observation was performed using a general scanning electron microscope (instrument name: JSM-IT200, manufactured by JEOL Ltd.) under the following conditions.

[0101] Acceleration voltage: 6kV Magnification: 10,000±5,000x The average crystal diameter was determined by first extracting 100±10 primary particles whose outlines were observed without interruption in the SEM image, measuring the longest diameter of each extracted primary particle, and calculating the average value.

[0102] (composition analysis) For the composition analysis, a sample solution was prepared by dissolving the sample in a mixed aqueous solution of hydrofluoric acid and nitric acid. The sample solution was measured by inductively coupled plasma atomic emission spectrometry (ICP-AES) using a general ICP device (device name: OPTIMA5300DV, manufactured by PerkinElmer). From the obtained measured values ​​of Si, Al, and Na, the SiO2 / Al2O3 ratio and Na content (alkali metal content) of the sample were obtained.

[0103] (BET specific surface area) The BET specific surface area of ​​the sample was determined by measurements in accordance with JIS Z 8830:2013. A general specific surface area measuring device (device name: BELSORP-miniII, manufactured by Microtrack BEL Co., Ltd.) was used for the measurements. As a pretreatment, the measurement sample was kept in a vacuum atmosphere (10 Pa or less) at 350°C for 2 hours. After the pretreatment, the BET specific surface area of ​​the measurement sample was measured by the one-point method using nitrogen as the adsorption gas.

[0104] (Toluene adsorption amount) The amount of toluene adsorption was measured using a general vapor adsorption measuring device (device name: BELSORP-MAXII, manufactured by Microtrac-Bell Co., Ltd.) in the following manner. 3 The sample tube was filled with 20 mg of MFI zeolite and held in a vacuum atmosphere (10 Pa or less) at 350°C for 2 hours to prepare a measurement sample. The sample tube filled with the measurement sample was set in a vapor adsorption measurement device, and the equilibrium pressure was changed from 0.001 to 1 kPa at 25°C, and the toluene adsorption amount [mass %] was measured at equilibrium pressures of 0.005 kPa, 0.01 kPa, 0.1 kPa, and 1 kPa.

[0105] (viscosity measurement) The viscosity was measured using a general viscometer (device name: MCR 92, manufactured by Anton Paar). The measurement sample was washed, solid-liquid separated, and then mixed with pure water to prepare a zeolite slurry with a solid content concentration of 51% by mass, which was used as the sample slurry. 2 mL of the sample slurry was dropped onto the stage of the measurement device equipped with a parallel plate type measurement jig (PP50), and the shear rate was set to 100 s -1 From 1200s -1 The shear rate was changed to 1100 s -1 The viscosity [mPa s] of the sample was measured. During the measurement, the stage temperature was set to 20°C, and the gap between the measurement jig and the stage was set to 0.2 mm.

[0106] Example 1 NBA, pure water, sodium hydroxide, and amorphous silicic acid containing 0.04% by mass of Al2O3 were mixed to obtain a raw material composition having the following molar composition.

[0107] SiO2 / Al2O3 ratio =4100 Na / SiO2 ratio =0.11 NBA / SiO2 ratio =0.23 H2O / SiO2 ratio =11 OH / SiO2 ratio =0.11 After mixing the seed crystals (MFI type zeolite, SiO2 / Al2O3 ratio: 2015, manufactured by Tosoh Corporation) with the raw material composition so that the seed crystal content was 1.0 mass%, 3600 g of the raw material composition was filled into a sealed container with a volume of 4 L, and hydrothermally treated at a pressure of 0.31 MPa and 120°C for 24 hours while stirring at 350 rpm, and then hydrothermally treated at 120°C while reducing the hydrothermal treatment pressure to 0.20 MPa at a pressure reduction rate of 0.20 MPa / hour. After the hydrothermal treatment, the temperature was lowered to 70°C, and the crystallized product was collected, which was used as the MFI type zeolite of this example.

[0108] The MFI zeolite of this example was a single-phase MFI zeolite (crystalline aluminosilicate) with a (020) / (101) peak ratio of 76% and a (101) / (501) peak ratio of 67%. The XRD pattern of the zeolite is shown in the table below.

[0109] [Table 4]

[0110] The MFI zeolite of this example has a SiO2 / Al2O3 ratio of 2500, an average crystal size of 1.25 μm, a Na content (alkali metal content) of 0.4 mass%, and a BET specific surface area of ​​392 m 2 / g, particle sizes were D10 0.77 μm, D50 1.64 μm, and D90 3.05 μm, with a standard deviation of 1.14 μm. The frequency volume particle size distribution curve was monomodal.

[0111] Example 2 NBA, pure water, sodium hydroxide, and amorphous silicic acid containing 0.77% by mass of Al2O3 were mixed to obtain a raw material composition having the following molar composition.

[0112] SiO2 / Al2O3 ratio =220 Na / SiO2 ratio =0.11 NBA / SiO2 ratio =0.23 H2O / SiO2 ratio =11 OH / SiO2 ratio =0.11 After mixing the seed crystals (MFI type zeolite, SiO2 / Al2O3 ratio: 2015, manufactured by Tosoh Corporation) with the raw material composition so that the seed crystal content was 1.0 mass%, 3600 g of the raw material composition was filled into a sealed container with a volume of 4 L, and hydrothermally treated at a pressure of 0.40 MPa and 130°C for 36 hours while stirring at 350 rpm, and then hydrothermally treated at 130°C while reducing the pressure to 0.27 MPa at a reduction rate of 0.20 MPa / hour. After the hydrothermal treatment, the sealed container was cooled to 70°C, and the crystallized product was collected, which was used as the MFI type zeolite of this example.

[0113] The MFI zeolite of this example was a single-phase MFI zeolite (crystalline aluminosilicate) with a (020) / (101) peak ratio of 78% and a (101) / (501) peak ratio of 65%. The XRD pattern of the zeolite is shown in the table below.

[0114] [Table 5]

[0115] The MFI zeolite of this example has a SiO2 / Al2O3 ratio of 200, an average crystal size of 1.16 μm, a Na content (alkali metal content) of 0.3 mass%, and a BET specific surface area of ​​381 m 2 / g, particle sizes were D10 1.40 μm, D50 2.69 μm, and D90 7.14 μm, with a standard deviation of 2.87 μm. The frequency volume particle size distribution curve was monomodal.

[0116] Example 3 The MFI zeolite of Example 1 was contacted with 7 mass% hydrochloric acid at 25°C for 5 minutes, washed with pure water, subjected to solid-liquid separation, and then dried in an air atmosphere at 110°C for 12 hours to obtain the MFI zeolite of this example.

[0117] The MFI zeolite of this example was a single-phase MFI zeolite (crystalline aluminosilicate) with a (020) / (101) peak ratio of 82% and a (101) / (501) peak ratio of 105%. The XRD pattern of the zeolite is shown in the table below.

[0118] [Table 6]

[0119] The MFI zeolite of this example has a SiO2 / Al2O3 ratio of 2500, an average crystal size of 1.25 μm, a Na content (alkali metal content) of 0.01 mass%, and a BET specific surface area of ​​338 m 2 / g, particle sizes were D10 0.77 μm, D50 1.64 μm, and D90 3.05 μm, with a standard deviation of 1.14 μm. The frequency volume particle size distribution curve was monomodal.

[0120] Example 4 The MFI zeolite of Example 1 was heat-treated in an air atmosphere at 600° C. for 2 hours to obtain the MFI zeolite of this example.

[0121] The MFI zeolite of this example was a single-phase MFI zeolite (crystalline aluminosilicate) with a (020) / (101) peak ratio of 82% and a (101) / (501) peak ratio of 137%. The XRD pattern of the zeolite is shown in the table below.

[0122] [Table 7]

[0123] The MFI zeolite of this example has a SiO2 / Al2O3 ratio of 2500, an average crystal size of 1.25 μm, a Na content (alkali metal content) of 0.4 mass%, and a BET specific surface area of ​​392 m 2 / g, particle sizes were D10 0.77 μm, D50 1.64 μm, and D90 3.05 μm, with a standard deviation of 1.14 μm. The frequency volume particle size distribution curve was monomodal.

[0124] Example 5 NBA, pure water, sodium hydroxide, and amorphous silicic acid containing 0.08% by mass of Al2O3 were mixed to obtain a raw material composition having the following molar composition.

[0125] SiO2 / Al2O3 ratio =2100 Na / SiO2 ratio =0.11 NBA / SiO2 ratio =0.23 H2O / SiO2 ratio =11 OH / SiO2 ratio =0.11 After mixing the seed crystals (MFI type zeolite, SiO2 / Al2O3 ratio: 2015, manufactured by Tosoh Corporation) with the raw material composition so that the seed crystal content was 1.0 mass%, 3600 g of the raw material composition was filled into a sealed container with a volume of 4 L, and hydrothermally treated at a pressure of 0.30 MPa and 120°C for 36 hours while stirring at 350 rpm, and then hydrothermally treated at 120°C while reducing the hydrothermal treatment pressure to 0.20 MPa at a pressure reduction rate of 0.20 MPa / hour. After the hydrothermal treatment, the temperature was lowered to 70°C, and the crystallized product was collected, which was used as the MFI type zeolite of this example.

[0126] The MFI zeolite of this example was a single-phase MFI zeolite (crystalline aluminosilicate) with a (020) / (101) peak ratio of 95% and a (101) / (501) peak ratio of 76%. The XRD pattern of the zeolite is shown in the table below.

[0127] [Table 8]

[0128] The MFI zeolite of this example has a SiO2 / Al2O3 ratio of 1500, an average crystal size of 1.32 μm, a Na content (alkali metal content) of 0.5 mass%, and a BET specific surface area of ​​310 m 2 / g, particle sizes were D10 1.15 μm, D50 1.99 μm, and D90 3.17 μm, with a standard deviation of 1.01 μm. The frequency volume particle size distribution curve was monomodal.

[0129] Comparative Example 1 The raw material composition obtained in the same manner as in Example 1 was subjected to hydrothermal treatment at a pressure of 0.31 MPa and 120° C. for 24 hours while stirring at 350 rpm. After the hydrothermal treatment, the temperature was lowered to 30° C., and the crystallized product was recovered and used as the MFI zeolite of this comparative example.

[0130] The MFI zeolite of this comparative example was a single-phase MFI zeolite (crystalline aluminosilicate) with a (020) / (101) peak ratio of 75% and a (101) / (501) peak ratio of 65%. The XRD pattern of the zeolite is shown in the table below.

[0131] [Table 9]

[0132] The MFI zeolite of this comparative example has a SiO2 / Al2O3 ratio of 2500, an average crystal size of 1.22 μm, a Na content (alkali metal content) of 0.4 mass%, and a BET specific surface area of ​​360 m 2 / g, particle sizes were D10 2.49 μm, D50 37.1 μm, and D90 76.1 μm, with a standard deviation of 36.8 μm. The frequency volume particle size distribution curve was bimodal.

[0133] Comparative Example 2 The raw material composition obtained in the same manner as in Example 1 was subjected to hydrothermal treatment at a pressure of 0.31 MPa and 120° C. for 24 hours, and then cooled to 70° C. After cooling, the composition was subjected to hydrothermal treatment at 70° C. while reducing the pressure to 0.10 MPa (atmospheric pressure) at a pressure reduction rate of 0.20 MPa / hour, and then the crystallized product was recovered and used as the MFI zeolite of this comparative example.

[0134] The MFI zeolite of this comparative example was confirmed to be a MFI zeolite (crystalline aluminosilicate) consisting of a single phase of MFI structure, with a (020) / (101) peak ratio of 75% and a (101) / (501) peak ratio of 73%. The XRD pattern of the zeolite is shown in the table below.

[0135] [Table 10]

[0136] The MFI type zeolite of this comparative example had a SiO2 / Al2O3 ratio of 2600, an average crystal size of 1.29 μm, a Na content (alkali metal content) of 0.4 mass%, and particle sizes D10 of 1.86 μm, D50 of 8.29 μm, and D90 of 38.8 μm, with a standard deviation of 18.5 μm. Also, the frequency volume particle size distribution curve was bimodal.

[0137] Comparative Example 3 The MFI zeolite of Comparative Example 1 was pulverized by the following method. That is, the MFI zeolite obtained in Comparative Example 1 was mixed with pure water to prepare a zeolite slurry having a solid content concentration of 30% by mass. The glass beads and the zeolite slurry were filled in a wet pulverizer (device name: DYNO-MILL, MULTI LAB, manufactured by WAB) so that the glass beads having a diameter of 1 mm were 80% by volume and the zeolite slurry was 20% by volume relative to the capacity of the wet pulverizer, and the mixture was pulverized at a peripheral speed of 10 m / s for 10 minutes to obtain a pulverized product.

[0138] The obtained ground material was contacted with 7 mass% hydrochloric acid at 25°C for 5 minutes, washed with pure water, separated into solid and liquid, and then dried in air at 110°C for 12 hours to obtain the MFI type zeolite of this comparative example.

[0139] The MFI zeolite of this comparative example was a single-phase MFI zeolite (crystalline aluminosilicate) with a (020) / (101) peak ratio of 99% and a (101) / (501) peak ratio of 106%. It was confirmed that the crystallinity of the MFI zeolite of this comparative example was reduced by pulverization compared to the MFI zeolite of the examples. The XRD pattern of the zeolite of this comparative example is shown in the table below.

[0140] [Table 11]

[0141] The MFI zeolite of this comparative example has a SiO2 / Al2O3 ratio of 2500, an average crystal size of 0.96 μm, a Na content (alkali metal content) of 0.01 mass%, and a BET specific surface area of ​​320 m 2 / g, particle sizes were D10 0.52 μm, D50 0.88 μm, and D90 1.76 μm, with a standard deviation of 0.62. The frequency volume particle size distribution curve was monomodal.

[0142] Comparative Example 4 NBA, pure water, sodium hydroxide, and amorphous silicic acid containing 6.0 mass% Al2O3 were mixed to obtain a raw material composition having the following molar composition.

[0143] SiO2 / Al2O3 ratio =26 Na / SiO2 ratio =0.20 NBA / SiO2 ratio =0.23 H2O / SiO2 ratio =11 OH / SiO2 ratio =0.20 After mixing the seed crystals (MFI type zeolite, SiO2 / Al2O3 ratio: 2015, manufactured by Tosoh Corporation) with the raw material composition so that the seed crystal content was 1.0 mass%, 3600 g of the raw material composition was filled into a sealed container with a volume of 4 L, and hydrothermally treated at a pressure of 0.41 MPa and 150°C for 36 hours while stirring at 350 rpm, and then hydrothermally treated at 130°C while reducing the pressure to 0.27 MPa at a pressure reduction rate of 0.22 MPa / hour. After the hydrothermal treatment, the sealed container was cooled to 70°C, and the crystallized product was collected, which was used as the MFI type zeolite of this comparative example.

[0144] The MFI zeolite of this comparative example was a single-phase MFI zeolite (crystalline aluminosilicate) with a (020) / (101) peak ratio of 76% and a (101) / (501) peak ratio of 54%. The XRD pattern of the zeolite is shown in the table below.

[0145] [Table 12]

[0146] The MFI zeolite of this comparative example has a SiO2 / Al2O3 ratio of 23, an average crystal size of less than 0.1 μm, a Na content (alkali metal content) of 2.1 mass%, and a BET specific surface area of ​​298 m 2 / g, particle sizes were D10 5.38 μm, D50 33.7 μm, and D90 74.7 μm, with a standard deviation of 34.7 μm. The frequency volume particle size distribution curve was bimodal.

[0147] Comparative Example 5 NBA, pure water, sodium hydroxide, and amorphous silicic acid containing 0.04% by mass of Al2O3 were mixed to obtain a raw material composition having the following molar composition.

[0148] SiO2 / Al2O3 ratio =3900 Na / SiO2 ratio =0.11 NBA / SiO2 ratio =0.23 H2O / SiO2 ratio =11 OH / SiO2 ratio =0.11 After mixing the seed crystals (MFI type zeolite, SiO2 / Al2O3 ratio: 2015, manufactured by Tosoh Corporation) with the raw material composition so that the seed crystal content was 1.0 mass%, 3600 g of the raw material composition was filled into a sealed container with a volume of 4 L, and hydrothermally treated at a pressure of 1.0 MPa and 170°C for 36 hours while stirring at 350 rpm, and then hydrothermally treated at 130°C while reducing the hydrothermal treatment pressure to 0.27 MPa at a pressure reduction rate of 0.20 MPa / hour. After the hydrothermal treatment, the temperature was lowered to 70°C, and the crystallized product was collected, which was used as the zeolite of this comparative example.

[0149] The zeolite in this comparative example was amorphous (non-crystalline aluminosilicate).

[0150] Measurement Example 1 (Viscosity measurement of zeolite slurry) The MFI zeolites of Example 1, Example 2, Comparative Example 1, Comparative Example 2, and Comparative Example 4 were mixed with pure water to prepare zeolite slurries with a solid content concentration of 51% by mass, and the viscosity of each zeolite slurry was measured. The results are shown in the table below.

[0151] [Table 13]

[0152] From the above table, the MFI type zeolite in the example is 1100s -1 The viscosity of the zeolite slurry at a shear rate of 1000 g / m2 was lower than that of the MFI zeolite of the comparative example. Therefore, it was confirmed that the MFI zeolite of the example has excellent handleability when made into a zeolite slurry without pulverization or the use of a dispersant, compared with the MFI zeolite of the comparative example.

[0153] Measurement example 2 (measurement of toluene adsorption amount) The toluene adsorption amounts of the MFI zeolites of Examples 1 to 5 and Comparative Example 3 were measured. The results are shown in the table below.

[0154] [Table 14]

[0155] From the above table, it was confirmed that the MFI zeolite of the Examples had a higher toluene adsorption amount at each equilibrium pressure than the MFI zeolite of the Comparative Example.

[0156] It was confirmed that the MFI zeolite of Comparative Example 3 had a (020) / (101) peak ratio of more than 95%, i.e., had a reduced crystallinity, and therefore had a reduced amount of toluene adsorbed at each equilibrium pressure.

[0157] [Table 15]

[0158] Since Example 3 had a Na content of 0.1 mass % or less, it was confirmed that the toluene adsorption amount was increased at each equilibrium pressure compared to Example 1. Furthermore, since Examples 3 and 4 had a (101) / (501) peak ratio of 80% or more and 140% or less, it was confirmed that the toluene adsorption amount was further improved at an equilibrium pressure of 0.01 kPa or more compared to Example 1.

Claims

1. A method for producing an MFI zeolite, comprising the steps of hydrothermally treating a composition containing a silica source, an alumina source, an alkali source, normal butylamine, and water at 100° C. or more and 150° C. or less and at 0.15 MPa or more, and then hydrothermally treating the composition at 100° C. or more and 150° C. or less while reducing the pressure at a reduction rate of 0.10 MPa / hour or more.

2. The method for producing MFI zeolite according to claim 1, wherein the composition has the following molar composition: SiO ２ / Al ２ O ３ Ratio = 50 or more but less than 5000 NBA / SiO ２ Ratio = 0.01 or more and 0.70 or less M / SiO ２ Ratio = 0.01 or more and 0.60 or less OH / SiO ２ Ratio = 0.01 or more 0.60 or less H ２ O / SiO ２ Ratio = 2 or more but less than 100 Here, NBA represents normal butylamine, and M represents an alkali metal element.

3. The method for producing MFI zeolite according to claim 1 or 2, wherein the silica source is an amorphous aluminosilicate.

4. The method for producing MFI type zeolite according to claim 1 or 2, wherein the alumina source is an amorphous aluminosilicate.

5. The method for producing MFI zeolite according to claim 1 or 2, wherein the hydrothermal treatment step is performed for 5 hours or more and 300 hours or less.

6. The MFI zeolite has a cumulative volume particle size distribution D50 of 0.5 μm or more and 5.0 μm or less, and in a powder X-ray diffraction pattern, a peak height of a (020) plane relative to a peak height of a (101) plane is 65% or more and 95% or less, a molar ratio of silica to alumina is 50 or more and 3000 or less, and an average crystal diameter is 0.1 μm or more and 3.0 μm or less.

Images