MFI-type 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 MFI-type zeolite and a method for producing the same.

Background Art

[0002] MFI-type zeolite is used in various industrial fields as an adsorbent for organic compounds. Generally, when using MFI-type zeolite as an adsorbent, from the viewpoint of increasing the adsorption efficiency, it is preferable to reduce the primary particle size and increase the specific surface area. As an MFI-type zeolite suitable as an adsorbent, for example, in Patent Document 1, a pentasil-type zeolite having a primary particle size of about 1 μm obtained by using normal propylamine as a structure-directing agent is disclosed.

[0003] On the other hand, when the primary particle size becomes about 5 μm or less, the primary particles tend to aggregate and easily form coarse secondary particles. As a result, the viscosity of the zeolite slurry increases, and the handleability deteriorates.

[0004] As a method for reducing the particle size of the zeolite particles contained in the slurry, particularly the particle size of the secondary particles, a method of adding a dispersant such as an organic substance to the zeolite slurry (for example, Patent Document 2), a method of pulverizing the zeolite powder, is known.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the MFI-type zeolite disclosed in Patent Document 1, aggregation of primary particles is remarkable, forming coarse particles. Therefore, it was not possible to obtain an MFI-type zeolite with 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 preferable because the dispersant affects the adsorption characteristics of the MFI-type zeolite.

[0008] There is also a method of pulverizing the MFI-type zeolite to reduce the particle size. However, in pulverization, as the particle size decreases, the crystallinity of the zeolite decreases, resulting in a decrease in adsorption performance.

[0009] An object of the present disclosure is to provide at least one of an MFI-type zeolite having a small average particle size and high adsorption performance for organic compounds, a method for producing the same, and an adsorbent containing the same, without using a dispersant or pulverization.

Means for Solving the Problems

[0010] The present disclosure has studied a method for producing an MFI-type zeolite that is excellent in handleability when made into a zeolite slurry without pulverization or use of a dispersant. As a result, it has been found that by controlling the pressure in a sealed container in the step of crystallizing the raw material, it is possible to directly crystallize an MFI-type zeolite having 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-type zeolite having a D50 in the cumulative volume particle size distribution of 0.5 μm or more and 5.0 μm or less, and a peak height ratio of the (020) plane to the peak height of the (101) plane in the powder X-ray diffraction pattern of 65% or more and 95% or less. [2] The MFI-type zeolite according to [1] above, having a molar ratio of silica to alumina of 50 or more and 3000 or less. [3] The MFI-type zeolite according to any one of the above [1] or [2], wherein the frequency volume particle size distribution curve is of a monomodal type. [4] The MFI-type zeolite according to any one of the above [1] to [3], wherein the standard deviation in the volume particle size distribution is 10 μm or less. [5] The MFI-type zeolite according to any one of the above [1] to [4], wherein the average crystal diameter is 0.1 μm or more and 5.0 μm or less. [6] The BET specific surface area is 300 m 2 / g or more, and the MFI-type zeolite according to any one of the above [1] to [5]. [7] A method for producing the MFI-type zeolite according to any one of the above [1] to [6], 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 higher and 150 ° C or lower and 0.15 MPa or higher, and then hydrothermally treating at 100 ° C or higher and 150 ° C or lower while reducing the pressure at a pressure reduction rate of 0.10 MPa / hour or more. [Effect of the Invention]

[0012] According to the present disclosure, at least one of an MFI-type zeolite having excellent handleability when made into a zeolite slurry and having high adsorption performance for organic compounds, and a method for producing the same, without requiring a method for adding a dispersant or a method for pulverizing zeolite powder. can be provided. [Embodiments for Carrying Out the Invention]

[0013] Hereinafter, an example of an embodiment of the MFI-type zeolite of the present disclosure will be shown and described. In the present disclosure, each configuration and parameter disclosed in this specification includes any combination, and the upper and lower limits of the values disclosed in this specification include any combination. The terms in this embodiment are as follows.

[0014] "Aluminosilicate" is a composite oxide having a structure composed of a network repetition of aluminum (Al) and silicon (Si) via oxygen (O). Among aluminosilicates, those having a crystalline XRD peak in their powder X-ray diffraction (hereinafter also referred to as "XRD") pattern are "crystalline aluminosilicates", and those not having a crystalline XRD peak are "amorphous aluminosilicates".

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

[0016] Accelerating current and voltage: 40 mA · 40 kV X-ray source: CuKα ray (λ = 1.5405 Å) Measurement mode: Continuous scan Scan condition: 10° / min Measurement range: 2θ = 5° to 40° Divergence vertical limit slit: 10 mm Divergence / incidence 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, device name: UltimaIV, manufactured by Rigaku Corporation). Also, the crystalline XRD peak is a peak whose 2θ at the peak top is specified and detected in the analysis of the XRD pattern using general analysis software, and an XRD peak with a full width at half maximum of 2θ = 0.10° or less can be exemplified.

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

[0018] "Zeolite-like substance" is a compound in which the T atoms have a regular structure through oxygen, and the compound contains at least atoms other than metals and semi-metals in the T atoms. Examples of zeolite-like substances include composite phosphorus compounds containing phosphorus (P) as the T atom, such as aluminophosphate (AlPO) and silicoaluminophosphate (SAPO).

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

[0020] In this embodiment, "zeolite of ~ type" such as "MFI type zeolite" means a zeolite having a zeolite structure of the corresponding structure code, and preferably means a crystalline aluminosilicate having a zeolite structure of the corresponding structure code. A zeolite having a zeolite structure of structure code "MFI" may be any zeolite having XRD peaks specified as an MFI type zeolite structure in its XRD pattern, and preferably has XRD peaks that can be identified as at least an MFI type zeolite structure.

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

[0022] The "average crystal diameter" is the average value of the particle diameters of the primary particles, and the primary particles are the smallest unit particles that are independently observed by scanning electron microscope (hereinafter also referred to as "SEM") observation 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.).

[0023] Accelerating voltage: 6 kV Magnification: 10,000 ± 5,000 times For the average crystal diameter, first, 100 ± 10 primary particles whose contours are observed continuously in the SEM observation image are extracted, the longest diameter of each of the extracted primary particles is measured, and the average value thereof is obtained, which can be taken as the average crystal diameter. The number of SEM observation images may be any number as long as the above-mentioned number of primary particles can be observed, and one or a plurality of SEM observation images may be used.

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

[0025] For the integration of the MFI-type zeolite, the frequency volume particle size distribution, and D10, D50, and D90, they may be measured under the following conditions using a general laser diffraction / scattering particle size distribution measuring device (for example, device name: Microtrac MT3300EXII, manufactured by Microtrac Bell Corporation).

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

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

[0028] Hereinafter, the MFI-type zeolite of the present embodiment will be described.

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

[0030] The MFI-type zeolite of this embodiment has a D50 of 0.5 μm or more and 5.0 μm or less. When the MFI-type zeolite with a D50 of less than 0.5 μm is made into a slurry, its viscosity is high, and its handleability (operability) is extremely low. Further, when D50 exceeds 5.0 μm, the viscosity of the slurry at a high shear rate tends to increase, and the fluidity decreases. The D50 of the MFI-type zeolite of this embodiment is 1.0 μm or more or 1.5 μm or more, and is 3.0 μm or less, preferably 1.0 μm or more and 3.0 μm or less, more preferably 1.5 μm or more and 3.0 μm or less.

[0031] The frequency volume particle size distribution curve of the MFI-type zeolite of this embodiment is preferably of a unimodal type. In this embodiment, the frequency volume particle size distribution curve being of a unimodal type means a frequency volume particle size distribution curve having a distribution with one peak. In other words, it is a curve having a shape with one peak in the frequency volume particle size distribution obtained by measuring the cumulative volume particle size distribution. Preferably, it is a curve having a shape with one inflection point in the frequency of particle diameters in the frequency volume particle size distribution curve.

[0032] The standard deviation (hereinafter also simply referred to as "standard deviation") in the volume particle size distribution of the MFI-type zeolite of this embodiment is preferably 10 μm or less. The standard deviation of the MFI-type zeolite of this embodiment is 7 μm or less or 5 μm or less, and is more than 0 μm or 0.5 μm or more. More preferably, it is more than 0 μm and 7 μm or less, and even more preferably 0.5 μm or more and 5 μm or less. By satisfying this standard deviation, when the MFI-type 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 obtained by the following formula.

[0034] Standard deviation [μm] = (D90 [μm] - D10 [μm]) / 2 The MFI-type zeolite of this embodiment has a (020) / (101) peak ratio in its XRD pattern of 65% or more and 95% or less. When the (020) / (101) peak ratio is outside the above range, the adsorption amount of the organic compound decreases. When an operation that applies strong stress to the particles, such as grinding, is applied to the MFI-type zeolite, the (020) / (101) peak ratio tends to increase. This is considered to be due to the decrease in the crystallinity of the MFI-type zeolite, and as a result, the adsorption amount of the organic compound tends to decrease. From the above points, the (020) / (101) peak ratio of the MFI-type zeolite of this embodiment is 70% or more or 75% or more, and is 85% or less. 70% or more and 85% or less is preferable, and 75% or more and 85% or less is more preferable.

[0035] The MFI-type zeolite of this embodiment preferably has a peak height ratio of the (101) plane to the peak height of the (501) plane (hereinafter, also referred to as the “(101) / (501) peak ratio”) in its XRD pattern of 50% or more and 140% or less. The (101) / (501) peak ratio is considered to be a value resulting from the oxygen 10-membered ring in the framework structure of the MFI-type zeolite. By removing the structure-directing agent (hereinafter, also referred to as “SDA”) and alkali metal elements in the oxygen 10-membered ring by the structure-directing agent removal step and cation exchange step described later, the numerical value tends to increase. Since the adsorption amount of the organic compound at an equilibrium pressure of 0.01 kPa or more is likely to improve, the (101) / (501) peak ratio of the MFI-type zeolite of this embodiment is 80% or more or 90% or more, and is 140% or less or 110% or less. 80% or more and 140% or less is preferable, and 90% or more and 110% or less is more preferable.

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

[0037] The XRD pattern shows the crystal structure of the MFI-type zeolite by one XRD pattern composed of a group of multiple XRD peaks having specific relative intensities, rather than the individual XRD peaks themselves indicating the crystal structure. A change in the lattice plane spacing and relative intensity of the XRD peaks means a change in the crystal structure. Therefore, the MFI-type zeolite of this embodiment can have its crystal structure specified by the group of XRD peaks having these relative intensities. Thus, when the crystal structure changes, the lattice plane spacing and relative intensity of the multiple XRD peaks change.

[0038] The MFI-type zeolite of this embodiment has an XRD peak specified as an MFI structure in its XRD pattern, and preferably has an XRD pattern including at least the following XRD peaks.

[0039]

Table 1

[0040] In this embodiment, the XRD pattern only needs to include each XRD peak in the above table, and may also include other XRD peaks attributed to the MFI structure.

[0041] It is more preferable that the MFI-type zeolite of this embodiment includes at least the following XRD peaks in its XRD pattern.

[0042]

Table 2

[0043] The MFI-type zeolite of this embodiment preferably further contains at least the following XRD peaks in its XRD pattern.

[0044]

Table 3

[0045] The MFI-type zeolite of this embodiment may contain XRD peaks with a relative intensity of less than 1% in addition to the above peaks. However, these low-intensity XRD peaks do not need to be considered for the identification of the crystal structure.

[0046] The MFI-type 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 within the above range, the adsorption performance for organic compounds tends 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-type 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 adsorption amount of organic compounds, the SiO2 / Al2O3 ratio of the MFI-type 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] The MFI-type zeolite of this embodiment has a ratio of the content of alkali metal (hereinafter also referred to as "alkali metal content") to the total content of silicon (Si), aluminum (Al), and alkali metal (M) in the MFI-type zeolite (hereinafter also referred to as "metal content") such that the adsorption amount of organic compounds is likely to be improved. The ratio is 0 mass% or more or more than 0 mass%, and is 0.5 mass% or less or 0.1 mass% or less. It is preferably 0 mass% or more and 0.5 mass% or less, more preferably more than 0 mass% and 0.1 mass% or less, and still more preferably 0 mass% or more and 0.05 mass% or less.

[0048] When there are two or more kinds of alkali metal elements contained in the MFI-type zeolite, the alkali metal content may be the total value of the contents of each metal element. For example, when the alkali metal elements include sodium (Na) and potassium (K), the ratio of the total content of sodium and potassium (hereinafter also referred to as "(Na + K) content") to the metal content of the MFI-type zeolite may be used, and it may be obtained 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 by dissolving the MFI-type zeolite in a mixed aqueous solution of hydrofluoric acid and nitric acid to prepare a sample solution, and using a general ICP device (for example, device name: OPTIMA5300DV, manufactured by PerkinElmer) to measure the sample solution by inductively coupled plasma atomic emission spectrometry (ICP-AES), and obtaining from the measured values of Si, Al, and M.

[0050] The MFI-type zeolite of this embodiment may contain SDA to the extent that it does not affect the adsorption performance for organic compounds. For example, when the total mass (weight value) of the MFI-type zeolite containing SDA is 100 mass%, the mass ratio of SDA contained in the MFI-type zeolite (hereinafter also referred to as "SDA content") is 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, if the average crystal diameter of the MFI-type zeolite is within the above range, it is 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 the 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 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 organic compounds 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 measurement in accordance with JIS Z 8830:2013. That is, using a general automatic specific surface area measuring device (for example, device name: BELSORP-miniII, manufactured by MicrotracBEL Corporation) and nitrogen as the adsorption gas, the BET specific surface area of the measurement sample may be measured by the single-point method. As a pretreatment, the measurement sample may be held in a vacuum atmosphere (10 Pa or less) at 350 ± 50 °C for 1 hour or more and 5 hours or less.

[0056] The MFI-type zeolite of the present embodiment has a low viscosity when made into a slurry, despite having high crystallinity compared to a conventional MFI-type zeolite after crystallization. For example, when the MFI-type zeolite of the present embodiment is made into a slurry using pure water as a solvent and having a solid content concentration of 51% by mass, the viscosity at a shear rate of 1100 s -1 can be exemplified to be 50 mPa·s or less, 30 mPa·s or less, and further 20 mPa·s or less. Although it is preferable that the viscosity is low, if the viscosity at a shear rate of 1100 s -1 is 1 mPa·s or more, and further 3 mPa·s or more, it will have a fluidity suitable for coating on a carrier of an adsorbent.

[0057] In the present embodiment, the viscosity at a shear rate of 1100 s -1 can be measured by the following method using a general viscometer (for example, device name: MCR 92, manufactured by Anton Paar). Mix the MFI-type zeolite and pure water to make a zeolite slurry with a solid content concentration of 51% by mass as a sample slurry. Drop 2 mL of the sample slurry onto the stage of a measuring device equipped with a parallel plate type measuring jig (PP50), and measure the viscosity at a shear rate of 1100 s -1 . During the measurement, the stage temperature is 20 °C, and the gap between the measuring jig and the stage is 0.2 mm.

[0058] The MFI-type zeolite of this example preferably has a toluene adsorption amount (hereinafter also referred to as "toluene adsorption amount") of 5.0 mass% or more, more preferably 5.5 mass% or more, and still more preferably 6.0 mass% or more with respect to the zeolite mass at an equilibrium pressure of 0.005 kPa. Also, the toluene adsorption amount at an equilibrium pressure of 0.01 kPa is preferably 5.0 mass% or more, more preferably 6.0 mass% or more, and still more preferably 7.0 mass% or more. Further, the toluene adsorption amount at an equilibrium pressure of 0.1 kPa is preferably 6.0 mass% or more, more preferably 7.0 mass% or more, and still more preferably 8.0 mass% or more. Also, the toluene adsorption amount at an equilibrium pressure of 1 kPa is preferably 8.0 mass% or more, more preferably 8.5 mass% or more, and still more preferably 9.0 mass% or more. Although the toluene adsorption amount at each equilibrium pressure is preferably higher, examples of the upper limit of the physical toluene adsorption amount include 25.0 mass% or less or 20.0 mass% or less. Furthermore, it is preferable that the toluene adsorption forces at equilibrium pressures of 0.005 kPa, 0.01 kPa, 0.1 kPa, and 1 kPa all satisfy the above values.

[0059] The toluene adsorption amount may be measured by the following method using a general vapor adsorption amount measuring device (for example, device name: BELSORP-maxII, manufactured by MicrotracBEL Corp.). As a pretreatment, a 11 cm 3 sample tube is filled with 20 ± 10 mg of MFI-type zeolite and held at 350 ± 50 °C for 1 hour or more and 5 hours or less in a vacuum atmosphere (10 Pa or less) to obtain a measurement sample. The sample tube filled with the measurement sample is set in a vapor adsorption amount measuring device, and the toluene adsorption amount [mass%] at 0.005 kPa, 0.01 kPa, 0.1 kPa, and 1 kPa is measured while changing the temperature to 25 °C and the equilibrium pressure from 0.001 to 1 kPa.

[0060] The MFI-type zeolite of this embodiment is preferably an aluminosilicate, and more preferably a crystalline aluminosilicate. Therefore, the MFI-type zeolite of this embodiment preferably does not contain phosphorus, and further preferably does not contain phosphorus (P) as a T atom. The phosphorus content of the MFI-type zeolite of this embodiment is preferably 100 mass ppm or less or 1 mass ppm or less, and also 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, the manufacturing method of the MFI-type zeolite of this embodiment will be described.

[0062] The manufacturing method of the MFI-type zeolite of this embodiment is a manufacturing method including a step (hereinafter, also referred to as a "crystallization 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 a "raw material composition") at 100°C or higher and 150°C or lower and 0.15 MPa or higher, and then hydrothermally treating at 100°C or higher and 150°C or lower while reducing the pressure at a pressure reduction rate of 0.10 MPa / hour or higher. By the crystallization step, the MFI-type zeolite of this embodiment is 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 that the D50 of the crystallized MFI-type zeolite is less likely to become 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 a compound of aluminum, 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 that the D50 of the crystallized MFI-type zeolite is less likely to become coarse, the alumina source is preferably one or more selected from the group consisting of aluminum oxide, aluminum sulfate, sodium aluminate, and amorphous aluminosilicate. From the viewpoint of reactivity, it is more preferably at least one of aluminum sulfate and amorphous aluminosilicate, and still more preferably amorphous aluminosilicate.

[0065] Particularly preferred alumina sources and silica sources include at least one of amorphous silica and aluminum sulfate, and amorphous aluminosilicate, with amorphous aluminosilicate being preferred. The SiO2 / Al2O3 ratio of the amorphous aluminosilicate may be 10 or more, 15 or more, or 20 or more, and 10,000 or less, 1,000 or less, or 80 or less, and is preferably 10 or more and 10,000 or less, 15 or more and 1,000 or less, or 20 or more and 80 or less.

[0066] When other starting materials contained in the raw material composition contain aluminum, this may be used as the alumina source. For example, when the silica source contains aluminum, the silica source can be regarded as the alumina source at the same time. Examples of such a silica source include amorphous aluminosilicates in which the content of aluminum in terms of Al2O3 is 0.001% by mass or more and 1.000% by mass or less based on the total mass of the silica source.

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

[0068] Examples of the alkali metal element include one or more selected from the group consisting of sodium, potassium, rubidium, and cesium. At least one of sodium and potassium is preferable, and sodium is more preferable.

[0069] The raw material composition contains normal butylamine (hereinafter also referred to as "NBA"). Thereby, the D50 of the crystallized MFI-type zeolite is less likely to become coarse, and an MFI-type zeolite having high adsorption performance for organic compounds can be easily obtained. The raw material composition only needs to contain NBA as the SDA source, and it is preferable that the SDA source is only NBA. However, in addition to NBA, an SDA source that directs the MFI structure may be included. Examples of the SDA source other than NBA include one or more amines selected from the group consisting of dinormal butylamine, tributylamine, dinormal propylamine, tripropylamine, dipropylene triamine, dihexamethylene triamine, triethylenetetramine, diethylenetriamine, ethanolamine, and propanolamine, at least one of tetrapropylammonium and tetraethylammonium quaternary ammonium cations, glycerol, alcohols, and morpholine.

[0070] Water may be one or more selected from the group consisting of distilled water, deionized water, and pure water. Further, moisture derived from other starting materials contained in the raw material composition, such as a solvent or a hydrate compound, is also regarded as water in the raw material composition.

[0071] In terms of suppressing the raw material cost, the raw material composition may not contain seed crystals, but since the processing time required for crystallization can be shortened, the raw material composition may contain a sufficiently small amount of seed crystals with respect to the silica source and the alumina source.

[0072] The seed crystal is preferably an MFI-type zeolite, and the SiO2 / Al2O3 ratio of the MFI-type zeolite is preferably 10 or more and 4000 or less.

[0073] The seed crystals contained in the raw material composition are such that the aluminum and silicon in the raw material composition (excluding the seed crystals), in terms of Al2O3 and SiO2 respectively, are in a proportion (hereinafter also referred to as the "seed crystal content") of the total mass of aluminum and silicon in the seed crystals, in terms of Al2O3 and SiO2 respectively, to the total mass of aluminum and silicon in the raw material composition (excluding the seed crystals) of 0 mass% or more or 1 mass% or more, and 20 mass% or less or 10 mass% or less. Preferred seed crystal contents include 0 mass% or more and 20 mass% or less, more than 0 mass% and 20 mass% or less, or 1 mass% or more and 10 mass% or less.

[0074] Preferred compositions of the raw material composition include the following molar compositions.

[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 However, 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 (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 200 or more and 4500 or less More preferably, it is 1000 or more and 4500 or less NBA / SiO2 ratio = 0.05 or more and 0.30 or less Preferably, it is 0.10 or more and 0.30 or less M / SiO2 ratio = 0.01 or more and 0.30 or less Preferably, it is 0.05 or more and 0.20 or less OH / SiO2 ratio = 0.01 or more and 0.30 or less, Preferably, it is 0.05 or more and 0.20 or less H2O / SiO2 ratio = 5 or more and 50 or less, Preferably, it is 8 or more and 15 or less In the present embodiment, it is preferable that the raw material composition does not contain fluorine (F) and fluorine-containing compounds (hereinafter also referred to as "fluorine etc."). Fluorine etc. are particularly highly corrosive, and a special manufacturing facility exhibiting corrosion resistance is required for a manufacturing method using the same. As a result, the manufacturing cost tends to be high. Therefore, it is preferable that the raw material composition 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 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 hydrothermally treated at 100°C or more and 150°C or less and 0.15 MPa or more. Thereby, the raw material composition crystallizes.

[0079] When the hydrothermal treatment temperature is less than 100°C, the time required for crystallization of the raw material composition becomes extremely long. On the other hand, when it exceeds 150°C, the secondary particle diameter, particularly D50, becomes too large. For this reason, 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). When the pressure is less than 0.15 MPa, the crystallinity of the obtained MFI-type zeolite is low and the adsorption performance is poor. 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 value, and one or more selected from the group consisting of the self-generated pressure, the method of introducing or sucking an atmospheric gas, and the method of compressing or expanding the volume of the sealed container filled with the raw material composition can be exemplified.

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

[0083] In the hydrothermal treatment, the raw material composition may be in either a stirred or stationary state, and a stirred state is preferred. The stirring speed may be appropriately adjusted according to the scale and structure of the apparatus used for crystallization, and examples include 30 rpm or more and 500 rpm or less, or 40 rpm or more and 400 rpm or less.

[0084] The time of the hydrothermal treatment may be adjusted according to the amount of the raw material composition subjected to the hydrothermal treatment and the crystallization temperature. Examples of the crystallization time that can be industrially applied include 5 hours or more or 10 hours or more, and also 300 hours or less, 200 hours or less, or 100 hours or less, and examples 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 into a sealed container. The sealed container only needs to be able to seal the raw material composition and have sufficient durability against the pressure generated when the hydrothermal treatment is carried out.

[0086] In the crystallization process, hydrothermal treatment is then carried out at a temperature of 100°C or higher and 150°C or lower while reducing the pressure at a rate of 0.10 MPa / hour or more (hereinafter also referred to as "vacuum hydrothermal treatment"). Thereby, from the raw material composition, the MFI-type zeolite having the D50 of the present embodiment can be directly crystallized. Although the reason why the MFI-type zeolite having the D50 of the present embodiment can be directly crystallized by performing hydrothermal treatment at the above-mentioned pressure reduction rate and temperature is not clear, by reducing the pressure at a rate of 0.10 MPa / hour or more, the raw material composition in the sealed container rolls, and aggregation of the crystallized particles is suppressed. As a result, it is considered that the MFI-type zeolite having a D50 of 0.5 μm or more and 5.0 μm or less can be directly crystallized.

[0087] In the crystallization process, by setting the temperature for heat treatment while performing pressure reduction treatment (hereinafter also referred to as "vacuum hydrothermal treatment temperature") to 100°C or higher and 150°C or lower, the MFI-type zeolite having the D50 of the present embodiment can be obtained. If the temperature is less than 100°C, the primary particles of the MFI-type zeolite tend to aggregate, and the D50 becomes excessively large. The vacuum hydrothermal treatment temperature is 105 or higher or 110°C or higher, and 140°C or lower or 130°C or lower can be mentioned. 105°C or higher and 140°C or lower is preferable, and 110°C or higher and 130°C or lower is more preferable.

[0088] The pressure reduction rate in the crystallization process is 0.10 MPa / hour or more. If the pressure reduction rate is less than 0.10 MPa / hour, the D50 tends to increase. The pressure reduction rate is preferably 0.10 MPa / hour or more and 0.30 MPa / hour or less, and 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 vacuum 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. Thereby, the D50 tends to be smaller, and the handleability of the slurry containing the MFI-type zeolite tends to be higher.

[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, more preferably 0.20 MPa or more and 0.50 MPa or less.

[0091] After the start of the reduced-pressure hydrothermal treatment, when the indicated value of the pressure is maintained for 1 hour or more in a state where it is less than the indicated value ±5 kPa (0.005 MPa) (hereinafter also referred to as the "stable state"), the reduced-pressure hydrothermal treatment may be terminated. The stable state only needs to be 1 hour or more, and examples include 1 hour or more and 10 hours or less.

[0092] In the production method of this embodiment, after the crystallization step, it may include one or more selected from the group 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 subjected to solid-liquid separation. In the washing step, solid-liquid separation may be performed by a known method, and the zeolite obtained as the solid phase may be washed with pure water.

[0094] In the drying step, the moisture physically adsorbed on the zeolite is removed. The drying conditions are arbitrary, and examples of drying the zeolite include standing in the atmosphere at 50°C or more and 250°C or less for 1 hour or more and 120 hours or less, or drying by a spray dryer.

[0095] The structure-directing agent removal step removes the SDA contained in the zeolite. As a method for removing the SDA, one or more selected from the group of exchange treatment with resin, pyrolysis treatment, and calcination treatment can be exemplified. 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 according to the amount of zeolite to be treated, and for example, in the atmosphere, it is 400°C or more and 700°C or less for 1 hour or more and 24 hours or less.

[0096] The MFI-type zeolite after crystallization may have an alkali metal element derived from an alkali source on its ion exchange site. In the cation exchange step, this is replaced with ammonium ca tion (NH 4+ ) or a proton (H+ ) and other non-metallic cations are subjected to cation exchange. Examples of the cation exchange to ammonium cations include a method of bringing the MFI-type zeolite into contact with an aqueous ammonium chloride solution. Examples of the cation exchange to protons include a method of bringing the MFI-type zeolite into contact with hydrochloric acid.

Examples

[0097] Hereinafter, the present disclosure will be described by way of examples. However, the present disclosure is not limited to these examples. (Identification of crystal phase) Using a powder X-ray diffractometer (device name: UltimaIV, manufactured by Rigaku Corporation), an XRD pattern was obtained under the following conditions.

[0098] Accelerating current and voltage: 40 mA·40 kV X-ray source: CuKα ray (λ = 1.5405 Å) Measurement mode: Continuous scan Scan condition: 10° / min Measurement range: 2θ = 5° to 40° Divergent vertical limiting slit: 10 mm Divergent / incident slit: 1° Scattering slit: Open Receiving slit: Open Detector: Semiconductor detector (D / teX Ultra2) Filter: Not used The crystal phase of the sample was identified by comparing the obtained XRD pattern with the XRD pattern described in MFI of Zeolite Framework Types on the homepage of the Structure Commission of IZA at http: / / www.iza-structure.org / databases / . (Volume particle size distribution) The volume particle size distribution was determined by measuring the frequency curve and cumulative curve of the volume particle size distribution using a laser diffraction / scattering particle size distribution measuring device (device name: Microtrac MT3300EXII, manufactured by Microtrac Bell Corporation). The measurement conditions are as follows.

[0099] Measurement range: 0.02 - 2000 μm Particle refractive index: 1.66 Particle permeability: Permeable 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 values of D10, D50, and D90, the standard deviation was calculated using the following formula.

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

[0101] Acceleration voltage: 6 kV Magnification: 10,000 ± 5,000 times For the average crystal diameter, first, 100 ± 10 primary particles whose contours were observed continuously in the SEM observation image were extracted, the longest diameter of each extracted primary particle was measured, and the average value was obtained, which was taken as the average crystal diameter.

[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. Using a general ICP device (equipment name: OPTIMA5300DV, manufactured by PerkinElmer), the sample solution was measured by inductively coupled plasma atomic emission spectrometry (ICP-AES). From the measured values of Si, Al, and Na obtained, the SiO2 / Al2O3 ratio and Na content (alkali metal content) of the sample were determined.

[0103] (BET specific surface area) The BET specific surface area of the sample was determined by measurement in accordance with JIS Z 8830:2013. For the measurement, a general specific surface area measuring device (device name: BELSORP-miniII, manufactured by MicrotracBEL Corp.) was used. As a pretreatment, the measurement sample was held at 350 °C for 2 hours in a vacuum atmosphere (10 Pa or less). For the measurement sample after the pretreatment, nitrogen was used as the adsorption gas, and the BET specific surface area was measured by the one-point method.

[0104] (Toluene adsorption amount) The toluene adsorption amount was measured by the following method using a general vapor adsorption amount measuring device (device name: BELSORP-MAXII, manufactured by MicrotracBEL Corp.). As a pretreatment, a sample tube of 11 cm 3 was filled with 20 mg of MFI-type zeolite, held at 350 °C for 2 hours in a vacuum atmosphere (10 Pa or less), and used as the measurement sample. The sample tube filled with the measurement sample was set in the vapor adsorption amount measuring device, the temperature was set to 25 °C, and the equilibrium pressure was changed from 0.001 to 1 kPa, and the toluene adsorption amounts [mass%] at equilibrium pressures of 0.005 kPa, 0.01 kPa, 0.1 kPa, and 1 kPa were measured.

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

[0106] Example 1 NBA, pure water, sodium hydroxide, and amorphous silicic acid having an Al2O3 content of 0.04 mass% 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 To the raw material composition, seeds (MFI-type zeolite, SiO2 / Al2O3 ratio: 2015, manufactured by Tosoh Corporation) were mixed so that the seed crystal content was 1.0% by mass. Then, 3600 g of the raw material composition was filled into a 4 L sealed container and hydrothermally treated at a pressure of 0.31 MPa and 120 °C for 24 hours while stirring at 350 rpm. After that, while reducing the hydrothermal treatment pressure to 0.20 MPa at a pressure reduction rate of 0.20 MPa / hour, the hydrothermal treatment was carried out at 120 °C. After the hydrothermal treatment, the temperature was lowered to 70 °C, and the crystallized product was recovered and used as the MFI-type zeolite of this example.

[0108] The MFI-type zeolite of this example consisted of a single phase of the MFI structure and was an MFI-type 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 following table.

[0109]

Table 4

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

[0111] Example 2 NBA, pure water, sodium hydroxide, and amorphous silica with an Al2O3 content of 0.77% by mass 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 For the raw material composition, seeds (MFI-type zeolite, SiO2 / Al2O3 ratio: 2015, manufactured by Tosoh Corporation) were mixed so that the seed content was 1.0% by mass. Then, 3600 g of the raw material composition was filled into a 4 L sealed container and hydrothermally treated at a pressure of 0.40 MPa and 130 °C for 36 hours while stirring at 350 rpm. After that, the pressure was reduced to 0.27 MPa at a pressure reduction rate of 0.20 MPa / hour while hydrothermally treating at 130 °C. After the hydrothermal treatment, the sealed container was cooled to 70 °C, and then the crystallized product was recovered and used as the MFI-type zeolite of this example.

[0113] The MFI-type zeolite of this example consisted of a single phase with an MFI structure and was an MFI-type 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 following table.

[0114]

Table 5

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

[0116] Example 3 The MFI-type zeolite of Example 1 was contacted with 7% by mass hydrochloric acid at 25°C for 5 minutes, then 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-type zeolite of this example.

[0117] The MFI-type zeolite of this example consisted of a single phase of the MFI structure and was an MFI-type 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 following table.

[0118]

Table 6

[0119] The MFI-type zeolite of this example had an SiO2 / Al2O3 ratio of 2500, an average crystal diameter of 1.25 μm, a Na content (alkali metal content) of 0.01% by mass, a BET specific surface area of 338 m 2 / g, a particle size with D10 being 0.77 μm, D50 being 1.64 μm, and D90 being 3.05 μm, and also had a standard deviation of 1.14 μm. Moreover, the frequency volume particle size distribution curve was of the unimodal type.

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

[0121] The MFI-type zeolite of this example consisted of a single phase of the MFI structure and was an MFI-type 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 following table.

[0122]

Table 7

[0123] The MFI-type zeolite of this example has an SiO2 / Al2O3 ratio of 2500, an average crystal diameter 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. The particle size was D10 = 0.77 μm, D50 = 1.64 μm, and D90 = 3.05 μm, and the standard deviation was 1.14 μm. Also, the frequency volume particle size distribution curve was of the monomodal type.

[0124] Example 5 NBA, pure water, sodium hydroxide, and amorphous silica with an Al2O3 content of 0.08 mass% 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 To the raw material composition, seeds (MFI-type zeolite, SiO2 / Al2O3 ratio: 2015, manufactured by Tosoh Corporation) were mixed so that the seed content became 1.0 mass%. Then, 3600 g of the raw material composition was filled into a 4 L sealed container and hydrothermally treated at a pressure of 0.30 MPa and 120 °C for 36 hours while stirring at 350 rpm. After that, while reducing the hydrothermal treatment pressure to 0.20 MPa at a pressure reduction rate of 0.20 MPa / hour, the hydrothermal treatment was carried out at 120 °C. After the hydrothermal treatment, the temperature was lowered to 70 °C, and the crystallized product was recovered and used as the MFI-type zeolite of this example.

[0126] The MFI-type zeolite of this example consisted of a single phase of the MFI structure and was an MFI-type 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-type zeolite of this example has a SiO2 / Al2O3 ratio of 1500, an average crystal diameter 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, the particle size is D10 = 1.15 μm, D50 = 1.99 μm, and D90 = 3.17 μm, and the standard deviation is 1.01 μm. Also, the frequency volume particle size distribution curve was of the unimodal type.

[0129] Comparative Example 1 The raw material composition obtained in the same manner as in Example 1 was hydrothermally treated 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-type zeolite of this comparative example.

[0130] The MFI-type zeolite of this comparative example consisted of a single phase of the MFI structure and was an MFI-type 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-type zeolite of this comparative example has a SiO2 / Al2O3 ratio of 2500, an average crystal diameter 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, the particle size is D10 = 2.49 μm, D50 = 37.1 μm, and D90 = 76.1 μm, and the standard deviation is 36.8 μm. Also, the frequency volume particle size distribution curve was of the bimodal type.

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

[0134] It was confirmed that the MFI-type zeolite of this comparative example consisted of a single phase of the MFI structure and was an MFI-type zeolite (crystalline aluminosilicate) 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 an SiO2 / Al2O3 ratio of 2600, an average crystal diameter of 1.29 μm, a Na content (alkali metal content) of 0.4% by mass, a particle size with D10 of 1.86 μm, D50 of 8.29 μm, and D90 of 38.8 μm, and also had a standard deviation of 18.5 μm. Further, the frequency volume particle size distribution curve was bimodal.

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

[0138] The obtained pulverized product was brought into contact with 7% by mass hydrochloric acid at 25 °C for 5 minutes, then washed with pure water, subjected to solid-liquid separation, and then dried at 110 °C for 12 hours in an air atmosphere to obtain the MFI-type zeolite of this comparative example.

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

[0140]

Table 11

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

[0142] Comparative Example 4 NBA, pure water, sodium hydroxide, and amorphous silica with an Al2O3 content of 6.0 mass% 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 To the raw material composition, seeds (MFI-type zeolite, SiO2 / Al2O3 ratio: 2015, manufactured by Tosoh Corporation) were mixed so that the seed content was 1.0% by mass. After that, 3600 g of the raw material composition was filled into a 4-L sealed container and hydrothermally treated at a pressure of 0.41 MPa and 150 °C for 36 hours while stirring at 350 rpm. Then, the pressure was reduced to 0.27 MPa at a pressure reduction rate of 0.22 MPa / hour and hydrothermally treated at 130 °C. After the hydrothermal treatment, the sealed container was cooled to 70 °C, and the crystallized product was recovered and used as the MFI-type zeolite of this comparative example.

[0144] The MFI-type zeolite of this comparative example consisted of a single phase with an MFI structure and was an MFI-type 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-type zeolite of this comparative example had an SiO2 / Al2O3 ratio of 23, an average crystal diameter of less than 0.1 μm, a Na content (alkali metal content) of 2.1% by mass, a BET specific surface area of 298 m 2 / g, particle sizes of D10 = 5.38 μm, D50 = 33.7 μm, and D90 = 74.7 μm, and a standard deviation of 34.7 μm. Also, the frequency volume particle size distribution curve was bimodal.

[0147] Comparative Example 5 NBA, pure water, sodium hydroxide, and amorphous silica with an Al2O3 content of 0.04% by mass 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 To the raw material composition, seed crystals (MFI-type zeolite, SiO2 / Al2O3 ratio: 2015, manufactured by Tosoh Corporation) were mixed so that the seed crystal content became 1.0% by mass. Then, 3600 g of the raw material composition was filled into a 4 L sealed container and hydrothermally treated at a pressure of 1.0 MPa and 170 °C for 36 hours while stirring at 350 rpm. After that, while reducing the hydrothermal treatment pressure to 0.27 MPa at a pressure reduction rate of 0.20 MPa / hour, hydrothermal treatment was carried out at 130 °C. After the hydrothermal treatment, the temperature was lowered to 70 °C, and the crystallized product was recovered and used as the zeolite of this comparative example.

[0149] The zeolite of this comparative example was amorphous (amorphous aluminosilicate).

[0150] Measurement Example 1 (Measurement of Viscosity of Zeolite Slurry) The MFI-type zeolites of Example 1, Example 2, Comparative Example 1, Comparative Example 2, and Comparative Example 4 were each mixed with pure water to form a zeolite slurry 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 viscosity of the zeolite slurry of the MFI-type zeolite of the example at a shear rate of 1100 s -1 was lower than that of the MFI-type zeolite of the comparative example. Therefore, it was confirmed that the MFI-type zeolite of the example was superior in handleability when made into a zeolite slurry without pulverization or use of a dispersant compared to the MFI-type zeolite of the comparative example.

[0153] Measurement Example 2 (Measurement of Toluene Adsorption Amount) The toluene adsorption amounts of the MFI-type 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-type zeolite of the example had a higher toluene adsorption amount at each equilibrium pressure than the MFI-type zeolite of the comparative example.

[0156] For the MFI-type zeolite of Comparative Example 3, since the (020) / (101) peak ratio exceeded 95%, that is, the crystallinity decreased, it was confirmed that the toluene adsorption amount decreased at each equilibrium pressure.

[0157]

Table 15

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

Claims

1. An organic compound adsorbent containing MFI-type zeolite, wherein D50 in the integrated volume particle size distribution is 0.5 μm or more and 5.0 μm or less, and the peak height of the (020) plane relative to the peak height of the (101) plane in the powder X-ray diffraction pattern is 65% or more and 95% or less, and the molar ratio of silica to alumina is 1000 or more and 3000 or less.

2. The organic compound adsorbent according to Claim 1, wherein the frequency volume particle size distribution curve of the MFI-type zeolite is of a monomodal type.

3. The organic compound adsorbent according to any one of Claims 1 or 2, wherein the standard deviation in the volume particle size distribution of the MFI-type zeolite is 10 μm or less.

4. The organic compound adsorbent according to any one of Claims 1 or 2, wherein the average crystal diameter of the MFI-type zeolite is 0.1 μm or more and 5.0 μm or less.

5. The BET specific surface area of the MFI-type zeolite is 300 m ２ / g or more, and the organic compound adsorbent according to any one of claims 1 or 2.

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