Amorphous aluminosilicate and method for producing zeolite using the same

Abstract

To provide at least one of a crystalline aluminosilicate obtained by an inexpensive production method and suitable as a starting material of AEI type zeolite, a method for producing the same, and a method for producing AEI type zeolite using the same as a starting material, and furthermore provide a simple method for producing FAU type zeolite with high silica composition.SOLUTION: An amorphous aluminosilicate characterized by the ratio of the total intensity of the maximum intensity I2 of a band with a wavenumber of 300 to 350 cm-1 and the maximum intensity I3 of a band with a wavenumber of 400 to 550 cm-1 to the maximum intensity I 1 of a band with a wavenumber of 750 to 850 cm-1 in a UV-Raman spectrum being 6.0 or more.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to an amorphous aluminosilicate suitable as a raw material for zeolites such as AEI zeolites, and a method for producing zeolites using the amorphous aluminosilicate as a starting material. [Background technology]

[0002] AEI-type zeolite is an artificially synthesized crystalline aluminosilicate (Patent Document 1), and zeolite having an FAU structure is mainly used as the starting material.

[0003] As conventional methods for producing AEI zeolite using a zeolite having an FAU structure as a starting material, a method using USY zeolite as a starting material (Non-Patent Document 1) and a method using a mixture of sodium silicate or colloidal silica and Y zeolite as a starting material (Patent Document 1, Non-Patent Documents 2 and 3) have been reported.

[0004] The USY zeolite used as the starting material is an FAU-type zeolite with a high silica composition, which is usually produced by post-treating (ultrastabilizing) Y zeolite after crystallization, such as by steaming. In contrast, a production method using a radical reaction using hydrogen peroxide has been investigated as a method for producing USY zeolite from only amorphous raw materials (Non-Patent Document 4). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] U.S. Patent No. 5,958,370 [Non-patent literature]

[0006] [Non-Patent Document 1] Chem. Mater., 32(2020)p60 [Non-patent document 2] J.Am.Chem.Soc.,122(2000)p263 [Non-patent document 3] Chem.Commun.,48(2012)p8264 [Non-patent document 4] Adv. Mater.,32(2020)2000272 Summary of the Invention [Problem to be solved by the invention]

[0007] USY zeolite is a zeolite obtained by subjecting zeolite Y to an ultrastabilization treatment, and is therefore very expensive to use as a starting material. Furthermore, the production method described in Non-Patent Document 4 requires expensive reaction equipment, and as a result, the USY zeolite obtained thereby is also expensive. Furthermore, a mixture of zeolite Y and a silica source (e.g., sodium silicate or colloidal silica) is likely to have a non-uniform composition when produced on an industrial scale, and when this mixture is used as a starting material for crystallization, impurities are likely to be produced as by-products.

[0008] An object of the present disclosure is to provide at least one of an amorphous aluminosilicate that can be obtained by an inexpensive production method and is suitable as a starting material for AEI zeolite, a production method thereof, and a production method for AEI zeolite using the same as a starting material. Another object is to provide a simple production method that can produce FAU zeolite with a high silica composition. [Means for solving the problem]

[0009] In the present disclosure, it has been discovered that an amorphous aluminosilicate obtained by acid treatment of an aluminosilicate gel having a specific silica-alumina ratio is suitable as a raw material for producing FAU-type zeolite having a high silica composition or AEI-type zeolite.

[0010] That is, the present invention is as described in the claims, and the gist of the present disclosure is as follows. [1] Wavenumbers 750-850cm in UV-Raman spectra -1 The maximum intensity I1 of the band is the wavenumber of 300 to 350 cm -1 The maximum intensity of the band I2 and the wavenumber 400-550 cm -1 The ratio of the maximum intensity of the band I1 to the total intensity of the band I2 is 6.0 or more. [2] The amorphous aluminosilicate according to [1] above, wherein the molar ratio of silica to alumina is 12 or more and 50 or less. [3] A method for producing an amorphous aluminosilicate according to the above item [1] or [2], comprising an acid treatment step of treating with acid an aluminosilicate gel that shows a powder X-ray diffraction pattern including a main peak having a peak top at 2θ=20.5 to 24.0° and a shoulder peak having a peak top at 2θ=26.0 to 32.0° and has a molar ratio of silica to alumina of 3 or more but less than 12. [4] The method according to the above [3], wherein the ratio of the peak area of the shoulder peak to the peak area of the main peak is 10% or more and 50% or less. [5] The method according to [3] or [4] above, wherein the acid is at least one selected from the group consisting of sulfuric acid, nitric acid, and hydrochloric acid. [6] The method according to any one of [3] to [5] above, wherein the acid concentration of the acid is 0.3N or more. [7] A method for producing an FAU-type zeolite, comprising a step of crystallizing a composition containing the amorphous aluminosilicate according to [1] or [2] above. [8] A method for producing AEI zeolite, comprising a step of crystallizing a composition containing the amorphous aluminosilicate according to [1] or [2] above. [Effects of the Invention]

[0011] The present disclosure provides at least one of an amorphous aluminosilicate that can be obtained by an inexpensive production method and is suitable as a starting material for AEI zeolite, a production method thereof, and a production method for AEI zeolite using the amorphous aluminosilicate as a starting material. Furthermore, the present disclosure provides a simple production method that can produce FAU zeolite with a high silica composition. [Brief explanation of the drawings]

[0012] [Figure 1] XRD pattern of the aluminosilicate gel of Example 1. [Figure 2] UV-Raman spectra of amorphous aluminosilicates of Example 1 and Comparative Example 1 (in the figure, a) is Example 1, and b) is Comparative Example 1). [Figure 3] 1 shows an XRD pattern of the FAU zeolite obtained in Example 2. [Figure 4] 27Al-MAS-NMR spectrum of the FAU zeolite obtained in Example 2. [Figure 5] 1 shows nitrogen adsorption isotherm of the FAU zeolite obtained in Example 2. [Figure 6] 2 is an SEM observation image of the FAU zeolite obtained in Example 2 (scale in the figure is 1 μm). [Figure 7] 1 shows an XRD pattern of the AEI zeolite obtained in Example 3. [Figure 8] 2 is an SEM image of the AEI zeolite obtained in Example 3 (scale in the figure: 1 μm). [Figure 9] XRD pattern of the product obtained in Comparative Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0013] The present disclosure will be described below by showing an example of an embodiment. Note that the terms used 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 "crystalline aluminosilicates," and those that do not have a crystalline XRD peak are "amorphous aluminosilicates."

[0015] In this embodiment, the XRD pattern is measured using CuKα radiation as a radiation source, and the measurement conditions include the following. Radiation source: CuKα radiation (λ=1.5406Å) Measurement mode: Step scan Scan speed: 4.0° per minute Measurement range: 2θ=3.0°~50.0°

[0016] The crystalline XRD peak is a peak detected by identifying the 2θ of the peak top in an XRD pattern analysis using general analysis software (e.g., SmartLab Studio II, manufactured by Rigaku Corporation). Although not particularly limited, the half-width (full width at half maximum) of the XRD peak can be, for example, 2θ = 0.50° or less.

[0017] "Zeolite" is a compound having a regular structure in which skeleton atoms (hereinafter also referred to as "T atoms") are connected via oxygen (O), and the T atoms are metal atoms. Zeolite may contain two or more types of metal atoms as T atoms. Note that the concept of metal atoms includes both atoms of metal elements and atoms of metalloid elements.

[0018] A "zeolite-like substance" is a compound having a regular structure in which T atoms are oxygen-mediated, and which contains at least an atom other than a metal (hereinafter also referred to as a "non-metal atom") as the T atom. As an example, a zeolite-like substance contains a metal atom and a non-metal atom as the T atom. Specific 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 "regular structure (hereinafter also referred to as "zeolite structure")" of zeolite or zeolite-like substances is a skeletal structure identified by the structure code (hereinafter also referred to simply as "structure code") established by the Structure Commission of the International Zeolite Association. For example, the FAU structure is a skeletal structure identified by the structure code "FAU." The zeolite structure can be identified by comparing it with the XRD pattern (hereinafter also referred to as "reference pattern") of each structure described in "Collection of simulated XRD powder patterns for zeolites," Fifth revised edition, p. 483 (2007). In this embodiment, the terms "zeolite structure," "skeletal structure," "crystalline structure," and "crystalline phase" are used interchangeably.

[0020] The "related structure" is a structure formed by linking structural units (Building Units) contained in the zeolite structure, and is a structure that cannot be identified as a zeolite structure when compared with the reference pattern.

[0021] In the present embodiment, "-type zeolite" such as "FAU-type zeolite" means a zeolite having a zeolite structure of the relevant structure code, and preferably means a crystalline aluminosilicate having a zeolite structure of the relevant structure code.

[0022] The amorphous aluminosilicate of the present disclosure will be described below by showing an example of an embodiment.

[0023] In this embodiment, the wavelength range of 750 to 850 cm in the UV-Raman spectrum -1 The maximum intensity I1 of the band is the wavenumber of 300 to 350 cm -1 The maximum intensity of the band I2 and the wavenumber 400-550 cm -1 The ratio of the maximum intensity I3 of the band to the total intensity of the band is 6.0 or more. The band is a band that includes an extreme value in the UV-Raman spectrum and has a wavenumber width of 30 cm. -1 More than 200cm -1 It is a broad peak with a peak width of 750 to 850 cm. The maximum intensity I1 is at a wavenumber of 750 to 850 cm. -1 The maximum intensity I2 is the maximum value of the band present in the wavenumber range of 300 to 350 cm. -1 The maximum intensity I3 is the maximum value of the band present in the wavenumber range of 400 to 550 cm. -1 This refers to the maximum value of the band present in

[0024] Wavenumbers of 300-350 cm in UV-Raman spectra -1 band (hereinafter referred to as "B 300-350 ), wave number 400-550 cm -1 band (hereinafter referred to as "B 400-550 ) and wavenumbers of 750 to 850 cm -1 band (hereinafter referred to as "B 750-850 ") are the bands corresponding to the TOT bending of the six-membered oxygen ring, the TOT bending of the four-membered oxygen ring, and the TOT symmetric stretching, respectively.

[0025] The amorphous aluminosilicate of this embodiment is B 750-850 For the maximum intensity I1, B 300-350 Maximum intensity I2 and B 400-550The ratio of the maximum intensity I2 to the total intensity I3 (=(I2+I3) / I1; hereinafter also referred to as the "Raman intensity ratio") is 6.0 or more, preferably 7.5 or more and 15.0 or less. By having such a Raman intensity ratio, the amorphous aluminosilicate of this embodiment contains many unit cells (hereinafter also referred to as "even cells") consisting of at least either a 4-membered ring or a 6-membered ring oxygen ring structure. This promotes the crystallization of FAU zeolite consisting of 4-membered rings, 6-membered rings, and 12-membered rings. The UV-Raman spectrum in this embodiment can be determined by the method described in the Examples below.

[0026] The even-numbered cells contained in the amorphous aluminosilicate of this embodiment may be, for example, at least one of s4r and s6r structural units as defined by the International Zeolite Society, thereby giving the amorphous aluminosilicate of this embodiment a structure similar to the FAU structure.

[0027] The amorphous aluminosilicate of this embodiment preferably has a molar ratio of silica to alumina (hereinafter also referred to as "SiO2 / Al2O3 ratio") of 12 to 50, more preferably 20 to 25, and 35 to 30. By having such an SiO2 / Al2O3 ratio, the amorphous aluminosilicate can be sufficiently dissolved even under the crystallization conditions of zeolite in a weakly basic atmosphere.

[0028] Next, a method for producing the amorphous aluminosilicate of this embodiment will be described.

[0029] The amorphous aluminosilicate of this embodiment exhibits a powder X-ray diffraction pattern including a main peak having a peak top at 2θ=20.5 to 24.0° and a shoulder peak having a peak top at 2θ=26.0 to 32.0°, and can be obtained by a method for producing an amorphous aluminosilicate, the method including an acid treatment step of treating, with acid, an aluminosilicate gel having a silica to alumina molar ratio of 3 or more and less than 12.

[0030] Here, a shoulder peak refers to a peak that partially overlaps with a main peak and has a peak-top intensity lower than that of the main peak. Because the shoulder peak and the main peak appear integrated in a powder X-ray diffraction pattern, the maximum values of the shoulder peak and the main peak may not be clearly visible in the powder X-ray diffraction pattern itself, and the peak-top positions (diffraction angles) of the shoulder peak and the main peak may not be identified from the powder X-ray diffraction pattern itself. In such cases, the peak-top positions of the main peak and the shoulder peak can be identified from the main peak and the shoulder peak obtained by peak separation. Known methods can be used for peak separation, and are not particularly limited. For example, a method of curve fitting (peak separation) using the least squares method based on an assumed function representing the peak can be used. Examples of functions representing the peak include a Gaussian function, a Lorentzian function, a mixed function of a Gaussian function and a Lorentzian function (Gauss-Lorentz), and a Voigt function. In addition, when the maximum values of the shoulder peak or main peak clearly appear in the powder X-ray diffraction pattern itself, the diffraction angle at these maximum values can be taken as the peak top position (diffraction angle) of the shoulder peak or main peak.

[0031] The acid treatment step causes aluminum to be released from the aluminosilicate gel, thereby obtaining the amorphous aluminosilicate of this embodiment.

[0032] In the acid treatment step, an aluminosilicate gel is provided which has, in a powder X-ray diffraction pattern, a main peak (hereinafter simply referred to as "main peak") having a peak top at 2θ=20.5 to 24.0° and a shoulder peak (hereinafter simply referred to as "shoulder peak") having a peak top at 2θ=26.0 to 32.0°, and which has a silica to alumina molar ratio of 3 or more and less than 12. The aluminosilicate gel is a precursor of the aluminosilicate of this embodiment. Conventional aluminosilicates have only a main peak, but the aluminosilicate gel subjected to the acid treatment step has the main peak and a shoulder peak. The 2θ of the peak top of the main peak is preferably 21.0 to 23.5°, and the 2θ of the peak top of the shoulder peak is preferably 27.0 to 30.0°.

[0033] The aluminosilicate gel preferably has a shoulder peak area relative to the main peak area (hereinafter also referred to as "area ratio") of 10% to 50%, more preferably 15% to 20%. The area ratio can be determined by the method described in the Examples below.

[0034] The SiO2 / Al2O3 ratio of the aluminosilicate gel is 3 or more and less than 12, and preferably 8 or more and 10 or less. When the SiO2 / Al2O3 ratio is in this range, the ring structure in the aluminosilicate gel tends to become regular. As a result, the formation of by-product phases is further suppressed in the production of amorphous aluminosilicate using the aluminosilicate as a raw material.

[0035] The aluminosilicate gel can be produced by any method, but examples thereof include mixing a composition containing a silicon source, an aluminum source, a sodium source, and water and having the following molar composition, followed by washing and drying: SiO2 / Al2O3 ratio = 4 or more and 15 or less H2O / SiO2 ratio =5 or more and 20 or less Na / SiO2 ratio = 0.5 or more and 1.0 or less

[0036] The silicon source may be any compound containing silicon (Si), and examples thereof include one or more selected from the group consisting of silica sol, fumed silica, colloidal silica, precipitated silica, and sodium silicate.

[0037] The aluminum source may be any compound containing aluminum (Al), and examples thereof include one or more selected from the group consisting of aluminum isopropoxide, aluminum sulfate, aluminum chloride, aluminum hydroxide, pseudoboehmite, alumina sol, and sodium aluminate.

[0038] The sodium source may be any compound containing sodium (Na), such as at least one of sodium hydroxide and sodium chloride. When another starting material, such as a silicon source, is a compound containing sodium, the compound may be used as the sodium source.

[0039] The water may be pure water, a solvent of other starting materials, or adsorbed water.

[0040] The mixing may be carried out so that the components contained in the composition are uniformly mixed, for example, at room temperature (20 to 30° C.) for 5 to 50 hours.

[0041] The washing may be carried out by any method capable of removing impurities from the aluminosilicate gel, and examples thereof include washing with pure water and / or washing with an acid solution exceeding 0N and less than 0.3N. The pure water and acid solution used for washing may be used in amounts that are in large excess (for example, 2 to 5 times) relative to the mass of the aluminosilicate gel. The unit of acid concentration, "N," is the molar concentration of the acid in terms of hydrogen ions ([H + ]mol / L).

[0042] Drying may be carried out by any method that removes moisture from the aluminosilicate gel, and examples thereof include treatment in the atmosphere at 80 to 120° C. for 5 to 24 hours.

[0043] In the production method of this embodiment, the acid treatment step involves treating the aluminosilicate gel with acid.

[0044] The acid is preferably an inorganic acid, and may be at least one selected from the group consisting of sulfuric acid, nitric acid, and hydrochloric acid, and may further be at least one of sulfuric acid and hydrochloric acid, or may further be sulfuric acid.

[0045] The acid is preferably 0.3N ([H + ] mol / L) or more or 0.6 N or more, and 4.0 N or less, 3.0 N or less, or 1.0 N or less. This facilitates the elimination of aluminum while partially maintaining the structural units of the aluminosilicate gel.

[0046] In the acid treatment step, the mass ratio of the aluminosilicate gel to the acid may be adjusted as appropriate, for example, aluminosilicate gel:acid ratio of 3.0:7.0 to 0.5:9.5.

[0047] The treatment in the acid treatment step may be any method that results in the desorption of aluminum from the aluminosilicate gel, and examples thereof include mixing the aluminosilicate gel and an acid under the following conditions. Processing temperature: above room temperature and below 100°C Processing time: 1 hour or more or 2 hours or more and 10 hours or less or 8 hours or less

[0048] After the acid treatment step, the resulting amorphous aluminosilicate may be recovered by any method, and may be washed and dried as necessary. For example, the recovery method may be filtration, the washing method may be water washing, and the drying method may be drying in the air at 90 to 150°C.

[0049] Next, a method for producing FAU-type zeolite using the amorphous aluminosilicate of this embodiment will be described.

[0050] The method for producing an FAU zeolite of the present embodiment may be any method for producing an FAU zeolite, characterized by having a step of crystallizing a composition containing the amorphous aluminosilicate of the present embodiment, and more specifically, it is a method for producing an FAU zeolite, including a step (hereinafter also referred to as a "crystallization step") of crystallizing a composition containing the amorphous aluminosilicate of the present embodiment, a structure-directing agent source, an alkali source, and water (hereinafter also referred to as a "raw material composition").

[0051] The amorphous aluminosilicate of this embodiment contains aluminum (Al) and silicon (Si), and therefore functions as an alumina source and a silica source. The alumina source and silica source contained in the raw material composition may consist solely of the amorphous aluminosilicate of this embodiment, or may contain at least one other alumina source and silica source (hereinafter also referred to as a "secondary alumina source" and a "secondary silica source," respectively) as necessary.

[0052] The secondary alumina source is a compound containing aluminum (Al), and examples thereof include one or more selected from the group consisting of aluminum isopropoxide, aluminum sulfate, aluminum chloride, aluminum hydroxide, pseudoboehmite, alumina sol, and aluminosilicate gel.

[0053] The secondary silica source is a compound containing 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, amorphous silicic acid, and amorphous aluminosilicate.

[0054] The source of the structure directing agent (hereinafter also referred to as "SDA") may be one or more selected from the group consisting of 1,1,3,5-tetramethylpiperidinium cation, 1,1-diethyl-2,6-dimethylpiperidinium cation, 1,1,2,6-tetramethylpiperidinium cation, 1-ethyl-1,2,6-trimethylpiperidinium cation, and 1,1,2-triethylpiperidinium cation, and is preferably at least one of 1,1,3,5-tetramethylpiperidinium cation and 1,1-diethyl-2,6-dimethylpiperidinium cation, and more preferably 1,1,3,5-tetramethylpiperidinium cation (hereinafter also referred to as "TMP"). + " is also called ".

[0055] The SDA source may be a salt of SDA, for example, one or more selected from the group consisting of hydroxide, chloride, bromide and iodide of SDA, and further includes hydroxide of SDA.

[0056] The alkali source is a compound containing an alkali metal element, and examples thereof include a compound containing one or more selected from the group consisting of sodium, potassium, cesium, and rubidium, a compound containing at least one of sodium and potassium, or a compound containing sodium. Examples of the alkali source include one or more selected from the group consisting of hydroxides, carbonates, chlorides, bromides, iodides, and sulfates containing alkali metal elements, and even hydroxides containing alkali metal elements. Particularly preferred alkali sources include at least one selected from the group consisting of sodium hydroxide, sodium carbonate, sodium chloride, sodium bromide, sodium iodide, and sodium sulfate, and even sodium hydroxide. The alkali source is not limited to salts; raw materials (starting materials) other than salts containing alkali metal elements, such as sodium silicate, can also be considered alkali sources.

[0057] The water contained in the raw material composition may be distilled water, deionized water, or pure water. In addition, water contained in other raw materials, such as hydrates, structural water, and solvents, can also be considered to be water contained in the raw material composition.

[0058] The following molar compositions can be given as preferred compositions of the raw material composition: Note that the ratios in the following compositions are molar (mol) ratios, SiO2 is silica (mol), Al2O3 is alumina (mol), HO is water (mol), M is alkali metal element (mol), SDA is organic structure directing agent (mol), OH is SiO2 (mol), Al2O3 is alumina (mol), HO is water (mol), M is alkali metal element (mol), SDA is organic structure directing agent (mol), OH is OH ... - is the total amount (mol) of hydroxide ions in the raw material composition. SiO2 / Al2O3 ratio = 12 or more or 14 or more, and 100 or less or 40 or less SDA / SiO2 ratio = 0.05 or more or 0.1 or more, and 0.4 or less or 0.3 or less M / SiO2 ratio = 0.01 or more or 0.05 or more, and 1.0 or less or less than 0.35 H2O / SiO2 ratio = 2 or more or 4 or more, and 20 or less or 15 or less OH - / SiO2 ratio = 0.1 or more or 0.2 or more, and 0.8 or less or 0.6 or less

[0059] It is preferable that the raw material composition does not substantially contain elements that require wastewater treatment after crystallization. Examples of such elements include fluorine (F) and phosphorus (P). The raw material composition may contain fluorine and phosphorus at or below the detection limit (for example, 0 mass ppm to 100 mass ppm, or even 0 mass % to 10 mass ppm).

[0060] In the crystallization step, the raw material composition may be crystallized so as to obtain FAU zeolite, and the crystallization method may be appropriately selected. A preferred crystallization method is to subject the raw material composition to hydrothermal treatment. The hydrothermal treatment may be carried out by placing the raw material composition in a sealed pressure-resistant container and heating it.

[0061] The hydrothermal treatment may be carried out after adding seed crystals (e.g., FAU zeolite) to the raw material composition. The seed crystals may be added, for example, in an amount of 0.2% by mass to 5% by mass in terms of the total mass of Si and Al in the seed crystals, calculated as SiO2 and Al2O3, respectively, relative to the total mass of Si and Al in the raw material composition (excluding the seed crystals), calculated as SiO2 and Al2O3, respectively. Examples of hydrothermal treatment conditions include the following. Treatment temperature: 110°C or higher, 130°C or higher, or 150°C or higher, and 220℃ or less, 210℃ or less, or 200℃ or less Processing time: 0.5 hours or more, 1 hour or more, or 1.5 hours or more, and Less than 8 hours or 7 hours or less Processing pressure: Autogenous pressure

[0062] The crystallization of the raw material composition in the crystallization step may be carried out either in a stationary state or in a stirred state. Since the composition of the resulting FAU zeolite will be more uniform, it is preferable to carry out the crystallization in a stirred state.

[0063] FAU zeolite can be obtained by the production method of this embodiment, which includes the above-described crystallization step.

[0064] The method for producing FAU zeolite of the present embodiment may include, after the crystallization step, one or more of a washing step, a drying step, an SDA removal step, an ammonium treatment step, and a heat treatment step.

[0065] The washing step is a step of washing the FAU zeolite. For example, in the washing step, the crystallized FAU zeolite and a liquid phase are subjected to solid-liquid separation by a known method, and then the FAU zeolite obtained as a solid phase may be washed with pure water.

[0066] The drying step is a step of removing moisture from FAU zeolite. The conditions for the drying step are arbitrary, but examples include drying the FAU zeolite in the atmosphere at 100°C or higher and 150°C or lower for 2 hours or longer by leaving it to stand or by using a spray dryer.

[0067] The SDA removal step is a step of removing SDA from FAU zeolite. Usually, zeolite crystallized in a crystallization step containing SDA contains SDA in its pores. Therefore, it is possible to remove SDA as needed.

[0068] The SDA removal step can be carried out by any method that can remove SDA from FAU zeolite. Examples of the SDA removal method include one or more methods selected from the group consisting of a liquid phase treatment using an acidic aqueous solution, an exchange treatment using a resin or the like, a thermal decomposition treatment, and a calcination treatment. From the viewpoint of production efficiency, the SDA removal step is preferably a thermal decomposition treatment or a calcination treatment.

[0069] The ammonium treatment step is a step of treating FAU zeolite with ammonium, and is carried out in order to remove alkali metals contained in the FAU zeolite. The ammonium treatment step can be carried out by a known method. For example, it can be carried out by contacting the FAU zeolite with an aqueous solution containing ammonium ions.

[0070] The heat treatment step is a step of heat treating the FAU type zeolite, for example, by heat treating the FAU type zeolite at 400°C or higher and 600°C or lower. + In the case of FAU zeolite (H type), the cation type is converted to the proton type (H type) by heat treatment at 400°C to 600°C. + More specific heat treatment conditions (calcination conditions) include air, 500°C, and 1 hour to 2 hours.

[0071] The FAU zeolite obtained by the method for producing an FAU zeolite of the present embodiment (hereinafter also referred to as "the present FAU zeolite") is a crystalline aluminosilicate having an FAU structure. More specifically, the present FAU zeolite is an FAU zeolite having a higher SiO / AlO ratio than zeolite Y, that is, a so-called USY zeolite.

[0072] The present FAU-type zeolite has an SiO2 / Al2O3 ratio of 6.5 or more, or 7.0 or more, and 40 or less, 20 or less, 12 or less, or 10 or less.

[0073] The present FAU zeolite may have any physical properties other than the SiO2 / Al2O3 ratio, but for example, it may have at least one of the following physical properties. BET specific surface area: 500m 2 / g or more or 540m 2 / g or more, 800m 2 / g or less or 760m 2 / g or less, Micropore volume: 0.20 mL / g or more or 0.24 mL / g or more, 0.38mL / g or less or 0.34mL / g or less, Adsorption / desorption hysteresis: 0 mL / g or more, 0.01 mL / g or more, or 0.1 mL / g or more 5.0mL / g or less or 1.0mL / g or less Particle size: 200 nm or more or 400 nm or more, 800nm or less or 700nm or less

[0074] It is preferable that the present FAU zeolite contains little aluminum other than T atoms (hereinafter also referred to as "extraframework Al"), and further contains no extraframework Al. When the amount of extraframework Al is small, aluminum is contained as T atoms. This stabilizes the FAU structure of the present FAU zeolite, despite the fact that the present FAU zeolite has a high SiO2 / Al2O3 ratio. Note that "does not contain extraframework Al" means that 27This means that the present FAU zeolite does not have a peak having a top at a chemical shift of 0±5 ppm in the Al-MAS-NMR spectrum (hereinafter also referred to as "extraframework Al peak"). However, it does not necessarily mean that the present FAU zeolite is completely free of extraframework Al. In other words, the present FAU zeolite that does not contain extraframework Al is 27 It is acceptable for the Al to be present in an amount that is not detectable in the Al-MAS-NMR spectrum.

[0075] The "adsorption / desorption hysteresis" refers to the difference between the amount of adsorbed nitrogen and the amount of desorbed nitrogen at a relative pressure of 0.5 in a nitrogen adsorption isotherm, and can be determined by the method described in the Examples below. Furthermore, the "particle size" refers to the longest diameter of each particle constituting the present FAU zeolite, and "the particle size being within a predetermined range" means that the particle diameter (longest diameter) of each particle constituting the present FAU zeolite is within a predetermined range. The particle diameter (longest diameter) of each particle can be measured from an SEM observation image, and the SEM observation image can be taken at any magnification such that the number of particles is, for example, approximately 50±20.

[0076] Next, a method for producing AEI zeolite using the amorphous aluminosilicate of this embodiment will be described.

[0077] The method for producing the AEI zeolite of the present embodiment may be such that the amorphous aluminosilicate of the present embodiment is used as a silica source and an alumina source, and is preferably a production method including a step of crystallizing a composition containing the amorphous aluminosilicate of the present embodiment, a structure-directing agent source, an alkali source, and water (hereinafter also referred to as a "raw material composition") (hereinafter also referred to as a "crystallization step").

[0078] The amorphous aluminosilicate contains aluminum (Al) and silicon (Si), and therefore functions as an alumina source and a silica source. The alumina source and silica source contained in the raw material composition are preferably only the amorphous aluminosilicate of this embodiment, but may contain at least one other alumina source and silica source, if necessary.

[0079] In the method for producing AEI zeolite of the present embodiment, the compositions of the amorphous aluminosilicate, the alumina source, the silica source, the structure-directing agent source, the alkali source, water, and the preferable raw material composition may be the same as those in the method for producing FAU zeolite of the present embodiment described above. AEI zeolite is crystallized by crystallizing the raw material composition containing the crystalline aluminosilicate of the present embodiment and the structure-directing agent source.

[0080] In the crystallization step, the raw material composition may be crystallized so as to obtain AEI zeolite, and the crystallization method may be selected as appropriate. A preferred crystallization method is to subject the raw material composition to hydrothermal treatment. The hydrothermal treatment may be carried out by placing the raw material composition in a sealed pressure-resistant container and heating it. As in the above-described method for producing FAU zeolite of the present embodiment, seed crystals (AEI zeolite) may be added to the raw material composition, and then the hydrothermal treatment may be carried out.

[0081] Preferred heat treatment conditions include, for example, the following. Treatment temperature: 110°C or higher, 130°C or higher, or 150°C or higher, and 210℃ or less, 200℃ or less, or 190℃ or less Processing time: 8 hours or more, 10 hours or more, or 15 hours or more, and 500 hours or less or 300 hours or less Processing pressure: Autogenous pressure

[0082] The method for producing AEI zeolite of the present embodiment may include, after the crystallization step, one or more of a washing step, a drying step, an SDA removal step, an ammonium treatment step, and a heat treatment step, which are similar to the method for producing FAU zeolite of the present embodiment described above.

[0083] The AEI zeolite obtained by the production method of this embodiment (hereinafter also referred to as "the present AEI zeolite") is a crystalline aluminosilicate having an AEI structure.

[0084] The present AEI zeolite has an SiO2 / Al2O3 ratio of 5.0 or more, or 10 or more, and 100 or less, 50 or less, 30 or less, or 25 or less.

[0085] The present AEI zeolite may have any physical properties other than the SiO2 / Al2O3 ratio, but for example, it may have at least one of the following physical properties. BET specific surface area: 500m 2 / g or more or 550m 2 / g or more, and 800m 2 / g or less or 750m 2 / g or less, Micropore volume: 0.20 mL / g or more or 0.24 mL / g or more, and 0.36 mL / g or less or 0.32 mL / g or less, [Example]

[0086] The present disclosure will be described in detail below with reference to examples, but the present disclosure is not limited to these examples.

[0087] (Calculation of XRD peak intensity) The product was subjected to XRD measurement using a general X-ray diffractometer (product name: Ultima-IV, manufactured by Rigaku Corporation) under the following measurement conditions. Radiation source: CuKα radiation (λ=1.5406Å) Measurement mode: Step scan Scanning conditions: 4.0° per minute Measurement time: 11.8 minutes Measurement range: 2θ=3.0°~50.0°

[0088] The obtained XRD pattern was subjected to baseline correction and detection and intensity analysis of each corrected XRD peak using an analysis program attached to the measuring device (trade name: SmartLab Studio II, manufactured by Rigaku Corporation).

[0089] In the examples and comparative examples shown below, the aluminosilicate was identified as being amorphous by confirming in the above-mentioned XRD pattern analysis that it did not have a crystalline XRD peak (a peak whose peak top 2θ was identified and detected).

[0090] For the XRD pattern of the aluminosilicate gel, the main peak and shoulder peak were separated using LightStone's ORIGIN2020 by peak fitting (peak separation) using the least squares method assuming a Gaussian function. The area ratio of the main peak to the shoulder peak was calculated from the separated main peak and shoulder peak.

[0091] (composition analysis) Composition analysis was performed using an ICP optical emission spectrometer (instrument name: iCAP-6300, manufactured by Thermo Fisher Scientific). The sample was dissolved in an aqueous potassium hydroxide solution, and the resulting solution was analyzed. From the analytical results, the SiO2 / Al2O3 ratio of the product was determined.

[0092] (SEM observation) Using a general scanning electron microscope (device name: JSM-7000F, manufactured by JEOL Ltd.), SEM images of the product were taken at an accelerating voltage of 5 kV.

[0093] ( 27 Al-MAS-NMR measurement) A typical magic angle spinning nuclear magnetic resonance spectrometer (JNM-ECA 500, manufactured by JEOL, 130.33 MHz) was used to measure the spectrum while rotating the sample at 14 kHz with a pulse length of 3.2 microseconds and a relaxation time of 5 seconds.

[0094] (UV-Raman) UV-Raman was performed using a microscopic laser Raman spectrometer (LabRAM HR Evolution, manufactured by Horiba, Ltd.) The sample was placed on a glass slide, and measurements were performed with a laser wavelength of 325 nm, a laser power of 6 mW, and an exposure time of 100 seconds for aluminosilicate gel and 300 seconds for amorphous aluminosilicate, with two measurements.

[0095] (adsorption / desorption hysteresis) Nitrogen adsorption isotherms were measured using a standard nitrogen adsorption apparatus (NOVAtouch, manufactured by Anton Paar). The nitrogen adsorption isotherms were obtained by pretreating the measurement sample by heating it at 150°C for 20 minutes and then at 350°C for 5 hours, followed by measurement at liquid nitrogen temperature using nitrogen as the adsorption medium. The adsorption / desorption hysteresis was calculated from the difference [mL / g] between the desorption amount and the adsorption amount at a relative pressure of 0.5 on the adsorption isotherm (= desorption amount [mL / g] - adsorption amount [mL / g]).

[0096] <Synthesis of amorphous aluminosilicate> Example 1 (Mixing process) A raw aqueous solution was obtained by mixing 27.0 g of a silica source (colloidal silica; Ludox-HS40), 3.4 g of an alumina source (sodium aluminate), sodium hydroxide, and pure water so that the SiO2 / Al2O3 ratio was 5.0, the H2O / SiO2 ratio was 15, and the Na / SiO2 ratio was 0.6. The raw aqueous solution was stirred at room temperature under atmospheric pressure for 24 hours to obtain a precipitate. The obtained precipitate was treated with pure water and 0.1 N sulfuric acid, and then dried in the air at 100°C for 12 hours to obtain an aluminosilicate gel.

[0097] The obtained aluminosilicate gel had a SiO2 / Al2O3 ratio of 9.6. Furthermore, peak separation of the XRD pattern of the aluminosilicate gel confirmed that the XRD pattern contained a main peak with a peak top at 2θ = 22.3° and a shoulder peak with a peak top at 2θ = 29.5°. The area ratio of the shoulder peak to the main peak was 16.0%. The XRD pattern of the obtained aluminosilicate gel is shown in Figure 1.

[0098] (Acid treatment process) The aluminosilicate gel and 0.8N sulfuric acid were mixed and stirred at room temperature for 3 hours to achieve a mass ratio of 1:9, and dealumination was performed. After mixing, the mixture was washed with a sufficient amount of pure water and dried in air at 100°C for 12 hours to obtain the amorphous aluminosilicate of this example.

[0099] The obtained amorphous aluminosilicate had a Raman intensity ratio of 8.4 and an SiO2 / Al2O3 ratio of 29.6. The UV-Raman spectrum is shown in Figure 2(a).

[0100] Comparative Example 1 The amorphous aluminosilicate of this comparative example was obtained in the same manner as in Example 1, except that a raw material aqueous solution with a Na / SiO2 ratio of 0.3 was used and the acid treatment step was not carried out.

[0101] The obtained amorphous aluminosilicate had a Raman intensity ratio of 5.1 and a SiO2 / Al2O3 ratio of 20.8.

[0102] The UV-Raman spectrum of this comparative example is shown in FIG. 2(b).

[0103] <Synthesis of high-silica FAU-type zeolite> Example 2 The amorphous aluminosilicate obtained in Example 1, 35.2 mass% TMPOH, sodium hydroxide, and pure water were mixed to obtain a raw material composition having the following composition. In the following molar composition, SDA is TMP.+ and M is Na. SiO2 / Al2O3=29.6 M / SiO2=0.10 H2O / SiO2=5.0 SDA / SiO2=0.20 OH - / SiO2=0.30

[0104] The raw material composition was mixed with 2 mass % of FAU zeolite as seed crystals (the ratio of the total mass of Si and Al in the seed crystals converted into SiO and AlO, respectively, to the total mass of Si and Al in the raw material composition (excluding the seed crystals) converted into SiO and AlO, respectively), and then the mixture was sealed in an autoclave, and the autoclave was left standing at 180°C for 3 hours to crystallize the raw material composition.

[0105] The resulting product was filtered, washed, and dried overnight in air at 110°C. The resulting product was FAU zeolite (crystalline aluminosilicate) with a SiO2 / Al2O3 ratio of 7.8. The XRD pattern of the FAU zeolite is shown in Figure 3. 27 The Al-MAS-NMR spectrum is shown in Figure 4, the adsorption isotherm in Figure 5, and the SEM image in Figure 6.

[0106] Figure 4 confirms that aluminum exists within the framework, i.e., aluminum is not contained other than that of T atoms. Figure 6 also confirms that the particle diameter is 450 to 650 nm, and Figure 5 confirms that the adsorption / desorption hysteresis is 0.2 mL / g.

[0107] (Synthesis of AEI-type zeolite) Example 3 The amorphous aluminosilicate obtained in Example 1, 35.2 mass% TMPOH, sodium hydroxide, and pure water were mixed to obtain a raw material composition having the following composition. In the following molar composition, SDA is TMP. + and M is Na. SiO2 / Al2O3=29.6 M / SiO2=0.10 H2O / SiO2=7.5 SDA / SiO2=0.20 OH - / SiO2=0.30

[0108] AEI zeolite was mixed as seed crystals to the raw material composition so that the amount was 2 mass % (the ratio of the total mass of Si and Al in the seed crystals converted into SiO and AlO, respectively, to the total mass of Si and Al in the raw material composition (excluding the seed crystals) converted into SiO and AlO, respectively), and the mixture was then sealed in an autoclave. The autoclave was left standing and treated at 190°C for 24 hours to crystallize the raw material composition.

[0109] The resulting product was filtered, washed, and dried overnight in air at 110°C. The resulting product was an AEI zeolite with a SiO2 / Al2O3 ratio of 13.2 and a BET specific surface area of 635 m 2 The XRD pattern of the AEI zeolite is shown in Fig. 7, and the SEM image is shown in Fig. 8.

[0110] The BET specific surface area was measured according to JIS8830 (Method for measuring the specific surface area of powders (solids) by gas adsorption). In this measurement, nitrogen was used as the adsorption gas, and the measurement temperature was -196°C. From the obtained adsorption isotherm, the BET specific surface area and micropore volume were calculated by the BET method (multipoint adsorption method) and the t-plot method, respectively.

[0111] Comparative Example 2 A product was obtained in the same manner as in Example 3, except that the amorphous aluminosilicate of Comparative Example 1 was used and the raw material composition was changed to the following composition. In the following molar composition, SDA was replaced by TMP. + and M is Na. SiO2 / Al2O3=20.8 M / SiO2=0.10 H2O / SiO2=7.5 SDA / SiO2=0.20 OH- / SiO2=0.30

[0112] The obtained product was a mixture of AEI, GME, and ANA zeolites. The identity of the obtained product was confirmed by comparing the XRD pattern (FIG. 9) with a reference pattern.

Claims

1. Wavenumber 750 to 850 cm in the UV-Raman spectrum measured by a microscopic laser Raman spectrometer －１ The maximum intensity I １ Wave number 300-350 cm －１ The maximum intensity I ２ and wave numbers of 400 to 550 cm －１ The maximum intensity I ３ The amorphous aluminosilicate is characterized in that the ratio of the total strength of the above-mentioned components is 7.5 or more and 15.0 or less.

2. 2. The amorphous aluminosilicate according to claim 1, wherein the molar ratio of silica to alumina is 12 or more and 50 or less.

3. 3. The method for producing amorphous aluminosilicate according to claim 1, further comprising an acid treatment step of treating with acid an aluminosilicate gel that shows a powder X-ray diffraction pattern including a main peak having a peak top at 2θ = 20.5 to 24.0° and a shoulder peak having a peak top at 2θ = 26.0 to 32.0° and has a molar ratio of silica to alumina of 3 or more and less than 12.

4. 4. The method according to claim 3, wherein the ratio of the peak area of the shoulder peak to the peak area of the main peak is 10% or more and 50% or less.

5. 5. The method according to claim 3, wherein the acid is at least one selected from the group consisting of sulfuric acid, nitric acid, and hydrochloric acid.

6. 6. The method according to claim 3, wherein the acid has an acid concentration of 0.3N or more.

7. A method for producing an FAU-type zeolite, comprising: a step of crystallizing a composition containing the amorphous aluminosilicate according to claim 1 or 2.

8. A method for producing AEI zeolite, comprising: a step of crystallizing a composition containing the amorphous aluminosilicate according to claim 1 or 2.

Images