JP7517397B2 - Method for producing AEI zeolite - Google Patents

Description

The present invention relates to a method for producing AEI zeolite.

AEI zeolite is an artificially synthesized crystalline aluminosilicate (Patent Document 1). The following method has been disclosed as a method for producing AEI zeolite.

Patent Document 1 discloses a method for producing AEI zeolite having a molar ratio of silica to alumina (hereinafter also referred to as " _{SiO2 / Al2O3} ratio") of more than 10 by crystallizing a mixture containing sodium silicate and Y zeolite.

Non-Patent Document 1 discloses a method for producing AEI zeolite by crystallizing a mixture containing sodium silicate and Y zeolite.

Non-Patent Document 2 discloses a method for producing AEI zeolite by crystallizing a mixture containing sodium silicate and USY zeolite, which is a zeolite having a Y zeolite structure and a high SiO ₂ /Al ₂ O ₃ ratio. The SiO ₂ /Al ₂ O ₃ ratios of the AEI zeolite were 18.2 and 14.8.

Patent Document 2 discloses a method for producing AEI zeolite having a SiO ₂ /Al ₂ O ₃ ratio exceeding 100, by crystallizing a mixture containing tetraethyl orthosilicate as a silica source, aluminum nitrate, and hydrofluoric acid. The SiO ₂ /Al ₂ O ₃ ratios of the AEI zeolite were 532 and 466.

Non-Patent Document 4 discloses a method for producing SSZ-39 by crystallizing raw materials containing colloidal silica, Y-type zeolite, and 1,1,3,5-tetramethylpiperidinium cations.

Non-Patent Document 5 discloses a method for producing SSZ-39 by crystallizing a raw material containing USY-type zeolite and 1,1,3,5-tetramethylpiperidinium cations.

U.S. Pat. No. 5,958,370 U.S. Patent Publication No. 2005/0197519

J. Am. Chem. Soc. , 122 (2000) p263 Chem. Commun. , 48 (2012) p8264 Chemistry Letters, 43 (2014) p302 The 30th Zeolite Research Symposium, A5 (2014) Chem. Commun. , 51 (2015) p11030

All of the methods for producing AEI zeolite having a SiO ₂ /Al ₂ O ₃ ratio of 100 or less that have been reported so far involve structurally converting a crystalline aluminosilicate having a Y-type structure into AEI zeolite.

Moreover, Patent Document 2 does not use a crystalline aluminosilicate having a Y-type structure. However, the AEI zeolite obtained only has a high SiO ₂ /Al ₂ O ₃ ratio exceeding 100. Furthermore, the production method of Patent Document 2 requires fluorine to produce AEI zeolite. Since fluorine is highly corrosive, a production method of AEI zeolite using fluorine requires special production equipment. In addition, since fluorine is contained in wastewater after the production of AEI zeolite, an additional process is required to treat this. Therefore, when the production method of AEI zeolite of Patent Document 2 is applied industrially, the production cost becomes significantly high.

For this reason, in a practical method for producing AEI zeolite, particularly in a method for producing AEI zeolite having a SiO ₂ /Al ₂ O ₃ ratio of 100 or less, the alumina source has been limited to a crystalline aluminosilicate having a Y-type structure. Crystalline aluminosilicate is expensive. For this reason, it has been difficult to apply a method for producing AEI zeolite using a crystalline aluminosilicate as an industrial production method.

In view of these problems, an object of the present invention is to provide a production method for obtaining AEI zeolite without relying on structural conversion of a crystalline aluminosilicate having a Y-type structure and without using fluorine or phosphorus. Another object of the present invention is to provide an industrial production method for AEI zeolite having a SiO ₂ /Al ₂ O ₃ ratio of 100 or less, while suppressing production costs.

The present inventors have investigated a method for producing AEI zeolite. As a result, they have discovered that by crystallizing a specific composition containing a specific structure directing agent and an alumina source, AEI zeolite can be produced without structural transformation of a crystalline aluminosilicate having a Y-type structure and without using fluorine.

That is, the present invention is a method for producing AEI zeolite, which includes a crystallization step of crystallizing a composition containing an alumina source, a silica source, a structure directing agent, a sodium source, and water, in which the weight ratio of crystalline aluminosilicate to the total weight of the alumina source and the silica source is 0% by weight or more and 10% by weight or less, and which satisfies at least one of the following: the molar ratio of hydroxide ions to silica in the composition is 0.45 or more, or the crystallization time is 80 hours or more.

The method for producing the AEI zeolite of the present invention is described below.

The present invention relates to a method for producing AEI zeolite. AEI zeolite is a zeolite having an AEI structure, and in particular an aluminosilicate having an AEI structure.

Aluminosilicates have a structure consisting of a repeating network of aluminum (Al) and silicon (Si) via oxygen (O).

The AEI structure is an AEI type structure according to the IUPAC structure code (hereinafter simply referred to as the "structure code") established by the Structure Commission of the International Zeolite Association.

The crystalline phase of AEI zeolite can be identified by comparing it with either the powder X-ray diffraction (hereinafter referred to as "XRD") pattern described in Collection of simulated XRD powder patterns for zeolites, Fifth revised edition, p. 483 (2007) or the XRD pattern described in AEI Zeolite Framework Types on the IZA Structure Committee's website at http://www.iza-structure.org/databases/.

An example of the AEI zeolite obtained by the production method of the present invention is SSZ-39. Furthermore, the production method of the present invention is suitable as a production method for AEI zeolite having a SiO ₂ /Al ₂ O ₃ ratio of 100 or less, and further suitable as a production method for AEI zeolite having a SiO ₂ /Al ₂ O ₃ ratio of 50 or less.

The manufacturing method of the present invention includes a crystallization step of crystallizing a composition containing an alumina source, a silica source, a structure directing agent, a sodium source, and water, in which the weight ratio of the crystalline aluminosilicate to the total weight of the alumina source and the silica source is 10% by weight or less. In the crystallization step, the composition containing the alumina source, the silica source, the structure directing agent, the sodium source, and water (hereinafter also referred to as the "raw material composition") is crystallized to obtain AEI zeolite.

The alumina source is a compound containing aluminum (Al). As an alumina source for producing zeolite, generally known are aluminum isopropoxide, aluminum sulfate, aluminum chloride, aluminum hydroxide, pseudoboehmite, alumina sol, amorphous aluminosilicate, crystalline aluminosilicate, and the like. Whether an artificially synthesized zeolite can be crystallized or not depends greatly on the type of aluminum compound used as the alumina source. The alumina source for obtaining a zeolite having a target structure is substantially limited, and even if the composition of the raw material composition is the same, a zeolite having a target structure cannot be obtained depending on the type of alumina source. AEI zeolite is an artificially synthesized crystalline aluminosilicate. The only method for producing an AEI zeolite having a SiO ₂ /Al ₂ O ₃ ratio of 100 or less was a method for reconstructing the structural unit of a crystalline zeolite contained in an alumina source, that is, a manufacturing method by structural transformation of a zeolite, specifically, a manufacturing method by structural transformation of a crystalline aluminosilicate having a Y-type structure. The crystalline aluminosilicate having a Y-type structure is a crystalline aluminosilicate having a structure that is classified as an FAU type in the structure code and has a SiO ₂ /Al ₂ O ₃ ratio of more than 3, and specifically includes at least one type selected from the group consisting of Y-type zeolite, USY-type zeolite, ZSM-3, ZSM-20, and LZ-210.

In contrast, in the production method of the present invention, AEI zeolite is obtained without structural transformation of crystalline aluminosilicate having a Y-type structure, and in particular, AEI zeolite having a SiO ₂ /Al ₂ O ₃ ratio of 100 or less is obtained. Therefore, the alumina source may be a compound containing aluminum other than crystalline aluminosilicate having a Y-type structure. Furthermore, in the production method of the present invention, since it is preferable to obtain AEI zeolite without structural transformation of crystalline aluminosilicate, it is preferable that the weight ratio of the crystalline aluminosilicate to the total weight of the alumina source and the silica source in the raw material composition is 10% by weight or less, and further, the weight ratio of the crystalline aluminosilicate having a structure that becomes FAU type to the total weight of the alumina source and the silica source is 10% by weight or less. Furthermore, in the raw material composition, the weight ratio of the crystalline aluminosilicate having a Y-type structure relative to the total weight of the alumina source and the silica source is preferably 10% by weight or less, further preferably 5% by weight or less, and further preferably 1% by weight or less, and it is preferable that the raw material composition does not substantially contain a crystalline aluminosilicate having a Y-type structure.

The alumina source is preferably an amorphous aluminum compound. This makes the manufacturing method of the present invention easier to apply industrially compared to the manufacturing method of AEI zeolite that uses crystalline aluminosilicate as the alumina source. Here, an amorphous aluminum compound is one that does not have a regular peak in XRD, and can be one that shows a wide halo pattern.

The alumina source is preferably at least one of the group consisting of aluminum hydroxide, aluminum oxide, aluminum sulfate, aluminum chloride, aluminum nitrate, amorphous aluminosilicate, crystalline aluminosilicate having a structure other than the Y-type structure, metallic aluminum, pseudoboehmite, alumina sol, and aluminum alkoxide, further at least one of the group consisting of aluminum oxide, aluminum nitrate, aluminum sulfate, aluminum chloride, aluminum hydroxide, pseudoboehmite, alumina sol, and amorphous aluminosilicate, at least one of the group consisting of aluminum oxide, aluminum sulfate, aluminum chloride, aluminum nitrate, amorphous aluminosilicate, pseudoboehmite, alumina sol, and aluminum alkoxide, and more preferably at least one of aluminum sulfate or amorphous aluminosilicate. This not only makes it possible to crystallize the AEI zeolite without the structural transformation of the crystalline aluminosilicate having the Y-type structure, but also makes it possible to crystallize the AEI zeolite without the structural transformation of the crystalline aluminosilicate. The amorphous aluminosilicate as the alumina source preferably has a silica content of more than 43% by weight ( _silicon content of more than 20% by weight), and examples of the amorphous aluminosilicate include those having a _SiO2 / _Al2O3 ratio of 1.4 or more and 2000 or less, further 1.4 or more and 100 or less, and further 1.4 or more and 50 or less.

The raw material composition may contain a crystalline aluminosilicate other than the crystalline aluminosilicate having a Y-type structure. However, when the amount of crystalline aluminosilicate in the raw material composition is large, the generation of AEI zeolite by zeolite conversion becomes dominant. Therefore, it is not preferable that the raw material composition contains a large amount of crystalline aluminosilicate. On the other hand, a small amount of crystalline aluminosilicate functions as a seed crystal, which promotes the nucleation of AEI zeolite. Therefore, the raw material composition may contain seed crystals, and the weight ratio of Si and Al in the crystalline aluminosilicate in the raw material composition converted into oxides to the total weight of Si and Al in the raw material composition converted into oxides (hereinafter also referred to as "(Si-Al) _Cry /(Si-Al) _Total ") is 0% by weight or more and 10% by weight or less, and preferably 0% by weight or more and 5% by weight or less. When the raw material composition contains a crystalline aluminosilicate, the content may be more than 0 wt % and not more than 10 wt %, further preferably 3 wt % or more and 5 wt % or less, and further preferably 4.1 wt % or more and 4.6 wt % or less.

The total weight of Si and Al in the raw material composition calculated as oxides may be determined by measuring the Si and Al in the raw material composition, converting them into _{SiO2 and Al2O3} , respectively, and using this total weight. Similarly, the weight of Si and Al in the crystalline aluminosilicate in the raw material composition may be determined by measuring the Si and Al in the crystalline aluminosilicate, converting them into _{SiO2 and Al2O3} , respectively, and using this total weight.

The crystalline aluminosilicate contained in the raw material composition is a crystalline aluminosilicate having a structure other than the Y-type structure, and further includes crystalline aluminosilicates other than Y-type zeolite, USY-type zeolite, ZSM-3, ZSM-20, and LZ-210. This makes it possible to produce AEI-type zeolite mainly by crystallization of amorphous aluminum compounds without causing structural transformation of Y-type zeolite even if crystalline aluminosilicate is present. Furthermore, when the raw material composition contains crystalline aluminosilicate, the crystalline aluminosilicate is at least one of the group consisting of AEI-type zeolite, CHA-type zeolite, KFI-type zeolite, and LEV-type zeolite, and is preferably at least one of AEI-type zeolite or CHA-type zeolite, and more preferably CHA-type zeolite. By including a small amount of CHA-type zeolite in the raw material composition, the production of crystalline aluminosilicates other than AEI-type zeolite, such as ANA-type zeolite, tends to be further suppressed.

The crystalline aluminosilicate contained in the raw material composition has an average particle size of 0.5 μm or more and 5 μm or less, further 0.5 μm or more and 4 μm or less, or even 0.85 μm or more and 4 μm or less.

The silica source is a compound containing silicon (Si). The silica source is preferably at least one selected from the group consisting of silica sol, fumed silica, precipitated silica, amorphous silicic acid, and amorphous aluminosilicate, and is preferably at least one of amorphous silicic acid and amorphous aluminosilicate.

Known structure directing agents (hereinafter also referred to as "SDAs") from which AEI zeolite can be obtained include piperidinium cation, pyrazolinium cation, pyrrolidinium cation, azonium [5,4] decane cation, azoniabicyclo [3,3,1] nonane cation, azoniabicyclo [3,2,1] octane cation, and candidinium cation.

In the production method of the present invention, the SDA is preferably a piperidinium cation, and is preferably at least one of N,N-alkyl-2,6-alkylpiperidinium cation (N,N-dialkyl-2,6-dialkylpiperidinium cation) or N,N-alkyl-3,5-alkylpiperidinium cation (N,N-dialkyl-3,5-dialkylpiperidinium cation), and more preferably at least one of 1,1-diethyl-cis-2,6-dimethylpiperidinium cation or 1,1-dimethyl-3,5-dimethylpiperidinium cation. Among the compounds known as SDAs from which AEI zeolite can be obtained, by using any of these cations as the SDA, the amount of expensive crystalline aluminosilicate used as an alumina source can be reduced.

The SDA contained in the raw material mixture is at least one of the group consisting of hydroxides, halides, and sulfates containing any of the above cations, and furthermore, the hydroxide or halide. Since general-purpose manufacturing equipment can be used, the SDA is at least one of the group consisting of hydroxides, chlorides, bromides, and iodides, and furthermore, at least one of the group consisting of hydroxides, chlorides, and bromides of the above cations. Particularly preferred SDAs include at least one of 1,1-dimethyl-3,5-dimethylpiperidinium hydroxide (hereinafter also referred to as "DMDMPOH") and 1,1-diethyl-cis-2,6-dimethylpiperidinium hydroxide (hereinafter also referred to as "DEDMPOH").

The sodium source is a compound containing sodium, and particularly includes a sodium compound exhibiting basicity. When the raw material composition contains sodium, AEI zeolite can be obtained from an amorphous alumina source. Specific examples of the sodium source include at least one of the group consisting of sodium hydroxide, sodium carbonate, sodium chloride, sodium nitrate, sodium bromide, sodium iodide, and sodium sulfate, and also sodium hydroxide. In addition, when the silica source or the alumina source contains sodium, the sodium can also be used as the sodium source.

The raw material composition preferably contains a compound containing an alkali metal other than sodium (hereinafter also referred to as "alkali metal source"). By containing an alkali metal source, the by-production of crystalline aluminosilicates having structures other than AEI zeolite is easily suppressed. The alkali metal source is a compound containing an alkali metal other than sodium, and is a compound containing at least one of the group consisting of potassium, rubidium, and cesium, and is further a hydroxide containing at least one of the group consisting of potassium, rubidium, and cesium.

The alkali metal source is preferably a compound containing potassium because it is easily available industrially, and more preferably at least one of the group consisting of potassium hydroxide, potassium carbonate, potassium chloride, potassium iodide, and potassium bromide. Furthermore, the alkali metal source is preferably potassium hydroxide because it is easily available industrially and relatively inexpensive.

The raw material composition contains water. The water contained in the raw material composition may be distilled water, deionized water, or pure water. It may also be water derived from other components contained in the raw material composition, such as an alumina source or a silica source.

The molar ratio of silica to alumina in the raw material composition (SiO ₂ /Al ₂ O ₃ ratio) is preferably 5 or more and 100 or less, and more preferably 5 or more and 90 or less. The SiO ₂ /Al ₂ O ₃ ratio of the obtained AEI zeolite is lower than the SiO ₂ /Al ₂ O ₃ ratio of the raw material composition. Therefore, when the SiO ₂ /Al ₂ O ₃ ratio is 100 or less, an AEI zeolite having a SiO ₂ /Al ₂ O ₃ ratio of 100 or less is obtained. Since the yield of AEI zeolite is further improved, the SiO ₂ /Al ₂ O ₃ ratio is preferably 10 or more, more preferably 15 or more, further preferably 20 or more, and further preferably 23 or more. The SiO ₂ /Al ₂ O ₃ ratio of the raw material composition may be 5 or more and 100 or less, further 10 or more and 65 or less, further 15 or more and less than 60, further 15 or more and 50 or less, and further 15 or more and less than 50.

In the case of obtaining an AEI zeolite having a _SiO2 / _Al2O3 ratio of 50 or _less , the _SiO2 / _Al2O3 ratio of the raw material composition is preferably from 20 to ₄₆ , further from 23 to 44, and further from 23 to 36. In the case of obtaining an AEI _zeolite having a _SiO2 / _Al2O3 ratio of 10 to ₃₀ , the _SiO2 / _Al2O3 ratio of the raw material composition is particularly preferably from 15 to less than 30, and further from 20 to 28.

The molar ratio of SDA to silica in the raw material composition (hereinafter also referred to as "SDA/ _SiO2 ratio") is preferably 0.05 or more. In order to further promote the crystallization of AEI zeolite, the SDA/ _SiO2 ratio is preferably 0.10 or more, more preferably 0.13 or more, and even more preferably 0.15 or more. From the viewpoint of reducing production costs, it is preferable that the amount of SDA is small, and the SDA/ _SiO2 ratio is preferably 0.40 or less, more preferably 0.30 or less, and even more preferably 0.25 or less. From the viewpoint of the efficiency of crystallization of AEI zeolite and the production costs, it is preferable that the SDA/ _SiO2 ratio of the raw material composition is 0.05 or more and 0.40 or less, more preferably 0.10 or more and 0.30 or less, even more preferably 0.13 or more and 0.25 or less, even more preferably 0.13 or more and 0.23 or less, and even more preferably 0.15 or more and 0.23 or less.

The molar ratio of sodium to silica in the raw material composition (hereinafter also referred to as "Na/ _SiO2 ratio") is preferably 0.01 or more and 1.0 or less, and more preferably 0.1 or more and 0.6 or less. Particularly preferred ranges of the Na/ _SiO2 ratio include 0.1 or more and less than 0.3, further 0.1 or more and 0.25 or less, further 0.1 or more and 0.2 or less, and further 0.1 or more and 0.18 or less.

The molar ratio of the alkali metal other than sodium to silica in the raw material composition (hereinafter also referred to as the "M/ _SiO2 ratio") may be 0 or more and 0.5 or less, further 0 or more and less than 0.3, further 0 or more and 0.2 or less, further 0 or more and 0.1 or less, or further 0 or more and 0.05 or less.

When the raw material composition contains an alkali metal source, the molar ratio of the alkali metal other than sodium to the sodium in the raw material composition (hereinafter also referred to as the "M/Na ratio") can be 0 or more and 2.0 or less, further more than 0 and 1.0 or less, further still more than 0.05 or more and 0.6 or less, and further still more than 0.1 or more and 0.6 or less. It is preferable that the ratio of the alkali metal other than sodium is equal to or less than the ratio of sodium, and the M/Na ratio can be 0.05 or more and 0.5 or less, further still more than 0.05 or more and 0.35 or less, further still more than 0.1 or more and 0.5 or less, and further still more than 0.1 or more and 0.45 or less.

When the raw material composition contains sodium and an alkali metal (M) other than sodium, the molar ratio of the alkali metal to silica in the raw material composition (hereinafter also referred to as "(M+Na)/ _SiO2 ") is preferably in the range of 0.1 to 0.6, further 0.1 to 0.5, and further 0.1 to less than 0.3. For example, the (M+Na)/ _SiO2 ratio may be 0.1 to 0.28, and further 0.1 to 0.25.

The molar ratio of water to silica in the raw material composition (hereinafter referred to as " _H2O / _SiO2 ratio") can be from 3 to 50, further from 5.0 to 50.0, and further from 5.0 to 25.0. By setting the _H2O / _SiO2 ratio within this range, AEI zeolite is easily crystallized from the amorphous alumina source.

In order to crystallize AEI zeolite from the amorphous alumina source in a shorter time, the H ₂ O/SiO ₂ ratio is preferably 5.0 or more and less than 20.0. In addition, when the raw material composition contains a crystalline aluminosilicate, the H ₂ O/SiO ₂ ratio is, for example, 8.0 or more and 15.0 or less.

The raw material composition contains hydroxide ions (OH ⁻ ). The hydroxide ions may contain hydroxide ions (OH ⁻ ) brought in from each component contained in the raw material composition. The hydroxide ions relative to silica in the raw material composition for crystallizing AEI zeolite (hereinafter also referred to as “OH ⁻ /SiO ₂ ratio”) may be 0.1 or more and 1.0 or less, further 0.2 or more and 0.8 or less, or further 0.3 or more and 0.8 or less. The higher the OH ⁻ /SiO ₂ ratio, the more the crystallization of AEI zeolite is promoted. If the OH ⁻ /SiO ₂ ratio is 0.45 or more, AEI zeolite crystallizes in an industrially applicable crystallization time. The OH ⁻ /SiO ₂ ratio is preferably 0.45 or more and 0.8 or less, further 0.47 or more and 0.8 or less. If the OH ⁻ /SiO ₂ ratio is 0.45 or more, the crystallization time may be 80 hours or more. However, if the OH ⁻ /SiO ₂ ratio is 0.45 or more, the AEI zeolite crystallizes in a single phase even if the crystallization time is less than 80 hours.

The raw material composition has the following molar composition: In the following compositions, the ratios are molar (mol) ratios, M is an alkali metal other than sodium, and SDA is an organic structure directing agent.

The composition is as follows :
SiO ₂ /Al ₂ O ₃ ratio: 10 or more and less than 60 SDA/SiO ₂ ratio: 0.1 or more and less than 0.30 Na/SiO ₂ ratio: 0.05 or more and less than 0.30 M/SiO ₂ ratio: 0.02 or more and less than 0.5 H ₂ O/SiO ₂ ratio: 9 or more and less than 20 OH ^- /SiO ₂ ratio: 0.45 or more and less than 0.8

The composition of the raw material composition may be any composition consisting of a combination of the ranges of the SiO ₂ /Al ₂ O ₃ ratio, SDA/SiO ₂ ratio, Na/SiO ₂ ratio, M/SiO ₂ ratio, (M+Na)/SiO ₂ ratio, M/Na ratio, H ₂ O/SiO ₂ ratio and OH ^- /SiO ₂ ratio described in this specification. In the present invention, the composition of the raw material composition can be determined by a general method.

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). When the raw material composition contains fluorine, it is necessary to use a corrosion-resistant material for the manufacturing equipment. Therefore, it is preferable that the raw material composition does not contain fluorine, that is, the fluorine content is 0 ppm by weight. However, considering the measurement error due to normal composition analysis, etc., the fluorine content of the raw material composition is below the detection limit, and further, 100 ppm by weight or less, or even 10 ppm by weight or less. Since the raw material composition does not contain fluorine or fluorine compounds, AEI type zeolite can be manufactured using general-purpose equipment. It is also preferable that the raw material composition does not contain phosphorus, and the phosphorus content is below the detection limit, and further, 100 ppm by weight or less, or even, 10 ppm by weight or less.

The fluorine and phosphorus contents in the raw material composition can be measured using common measurement methods such as ICP.

In the crystallization step, as long as the raw material composition is crystallized, the crystallization method can be appropriately selected. A preferred crystallization method is to subject the raw material composition to hydrothermal treatment. The hydrothermal treatment can be performed by placing the raw material composition in a sealed pressure-resistant container and heating it. The hydrothermal treatment conditions can be as follows.
Treatment temperature: any temperature between 100°C and 200°C, preferably between 130°C and 190°C, more preferably between 140°C and 180°C Treatment pressure: autogenous pressure

The crystallization time is preferably 80 hours or more, and more preferably 100 hours or more. When the crystallization time is 80 hours or more, the OH ^- /SiO ₂ ratio may be 0.45 or more, but if the crystallization time is 80 hours or more, the AEI zeolite crystallizes in a single phase even if the OH ^- /SiO ₂ ratio of the raw material composition is less than 0.45. The crystallization time may be 500 hours or less, more preferably 300 hours or less, or even 200 hours or less.

If the OH ^- /SiO ₂ ratio is less than 0.45, the AEI zeolite crystallizes into a single phase for a crystallization time of 120 hours or more, and even 150 hours or more. Also, if the OH ^- /SiO ₂ ratio is 0.45 or more, the AEI zeolite crystallizes into a single phase even if the crystallization time is 75 hours or less, and even if the crystallization time is 50 hours or less.

The raw material composition in the crystallization step may be in a stationary state or in a stirred state. Since the composition of the resulting AEI zeolite will be more uniform, it is preferable to perform the crystallization in a state where the raw material composition is stirred. The resulting AEI zeolite may be crushed or pulverized as necessary.

The method for producing AEI zeolite of the present invention may include one or more of a washing step, a drying step, an SDA removal step, an ammonium treatment step, or a heat treatment step after the crystallization step.

In the washing process, the crystallized AEI zeolite is separated from the liquid phase. In the washing process, solid-liquid separation is performed using a known method, and the AEI zeolite obtained as a solid phase is washed with pure water.

The drying process removes moisture from the AEI zeolite after the crystallization process or the washing process. The conditions for the drying process are arbitrary, but an example of the drying process is drying the AEI zeolite after the crystallization process or the washing process in the air at 50°C or higher and 150°C or lower, or even 100°C or higher and 150°C or lower, for 2 hours or more, by leaving it to stand or by using a spray dryer.

The SDA removal process is carried out to remove the SDA contained in AEI zeolite. Normally, AEI zeolite that has undergone the crystallization process contains SDA in its pores. Therefore, it can be removed as necessary.

The SDA removal step can be carried out by any method that removes SDA. Examples of such removal methods include at least one of the following: liquid phase treatment using an acidic aqueous solution, exchange treatment using a resin or the like, pyrolysis treatment, and calcination treatment. From the viewpoint of production efficiency, it is preferable that the SDA removal step is either pyrolysis treatment or calcination treatment.

The ammonium treatment step is carried out to remove the alkali metals contained in the AEI zeolite. The ammonium treatment step can be carried out by a general method. For example, it can be carried out by contacting an aqueous solution containing ammonium ions with the AEI zeolite.

In the heat treatment step, the AEI zeolite is heat-treated at 400° C. or more and 600° C. or less. When the AEI zeolite has an ammonium cation type (NH ₄ ⁺ type), the heat treatment results in AEI zeolite having a proton cation type (H ⁺ type). More specific firing conditions include air, 500° C., and 1 to 2 hours.

In the conventional method for producing AEI zeolite, the difference between the SiO ₂ /Al ₂ O ₃ ratio of the raw material composition and the SiO ₂ /Al 2 O ₃ ratio of the obtained AEI zeolite is smaller than that in the conventional method for producing _AEI zeolite by zeolite conversion. For example, in the production method of the present invention, even when a raw material composition having a high hydroxide ion content with an OH ^- /SiO ₂ ratio of 0.49 or more and 0.72 or less is used, the SiO ₂ /Al ₂ O ₃ ratio of the obtained AEI zeolite relative to the SiO ₂ /Al ₂ O ₃ ratio of the raw material composition (hereinafter also referred to as "SAR rate of change") is 60% or less, and further 58% or less. The lower the SAR rate of change, the more efficient the crystallization of AEI zeolite from the raw material composition. Therefore, the SAR change rate in the production method of the present invention, particularly the SAR change rate when the OH ⁻ /SiO ₂ ratio of the raw material composition is 0.36 or more and 0.49 or less, is preferably 55% or less, further preferably 50% or less, further preferably 48% or less, and further preferably 45% or less.

Since the production method of the present invention has a low SAR change rate at a high OH ^- /SiO ₂ ratio, it is particularly suitable as a production method for obtaining AEI zeolite having a SiO ₂ /Al ₂ O ₃ ratio of 50 or less, further 25 or less, and even 15 or more and 25 or less.

In the crystallization process, for example, the yield of AEI zeolite calculated by the following formula is greater than 40%, 50% or more, or even 70% or more, or even 75% or more.

Yield (wt%) = (total weight of Al ₂ O ₃ and SiO ₂ in AEI zeolite)
/ (total weight of Al ₂ O ₃ and SiO ₂ in the raw material composition) × 100
Here, the total weight of Al ₂ O ₃ and SiO ₂ in AEI zeolite is the total weight obtained by measuring the Al content in the AEI zeolite and converting it into Al ₂ O ₃ , and measuring the Si content in the AEI zeolite and converting it into SiO _2. The total weight of Al ₂ O ₃ and SiO ₂ in the raw material composition can also be obtained by a similar method.

In the present invention, it is preferable that the ratio of zeolite solids to the components other than water in the raw material composition (hereinafter also referred to as "solids recovery rate") is high. By increasing the solids recovery rate, the amount of unused components discharged from the manufacturing process of the manufacturing method of the present invention is reduced, and the burden on the environment is reduced. The solids recovery rate is a value calculated using the following formula.

Solid recovery rate (%)
= (total weight of metals in AEI zeolite converted into oxide)
÷ (total weight of components other than water in the raw material composition) × 100 Here, the weight of metals calculated as oxides can be found by converting alkali metal elements such as Si, Al, Na, and K into alkali metal oxides such as _SiO2 , _Al2O3 , _Na2O , and _{K2O ,} respectively.

The AEI zeolite obtained by the production method of the present invention has a _SiO2 / _{Al2O3 ratio} suitable for use as a catalyst carrier, and _{the SiO2} / _Al2O3 ratio is 100 or less, further 50 or less, further 30 or less, further 25 or less, and 10 or more, further 14 or more, further 15 or more. Particularly preferred _SiO2 / _Al2O3 ratios _are 10 or more and 100 or less, further 14 or more and 50 or less, further 15 or more and 30 or less.

The AEI zeolite obtained by the manufacturing method of the present invention has an average crystal size of 0.1 μm or more, and even 0.5 μm or more, and 5 μm or less, and even 2 μm or less. Particularly preferred average crystal sizes are 0.5 μm or more and 8 μm or less, and even 0.5 μm or more and 2 μm or less. This makes it less likely to deteriorate even when exposed to a hydrothermal atmosphere. In addition, such an average crystal size makes it less likely for the particles to aggregate, and is expected to improve the applicability to the catalyst substrate.

The crystal size in the present invention is the particle size of the primary particles, and is the diameter of the smallest independent particle unit observed under an electron microscope. The average crystal size is the arithmetic mean of the crystal sizes of 30 or more primary particles randomly sampled under an electron microscope. Therefore, the secondary particle size, which is the diameter of a secondary particle formed by agglomeration of multiple primary particles, and the average secondary particle size are different from the crystal size and average crystal size. The shape of the primary particles may be at least one of the group consisting of a cubic crystal shape, a tetragonal crystal shape, and a twin crystal shape that is a combination of a cubic crystal shape or a tetragonal crystal shape.

The packing property of AEI zeolite can be adjusted to some extent by the conditions of the crystallization step and the treatment step after crystallization. The packing property of the AEI zeolite of the present invention is 0.1 g/cm3 or more and 0.5 g/cm3 or less in terms of ^{loose bulk} density. When the loose bulk density is in this range, the AEI zeolite has practical packing property as a catalyst, adsorbent, etc. The loose bulk density is the bulk density when the AEI zeolite that has been passed through a sieve is allowed to fall naturally and filled into a container, and this can be measured by a general powder property measuring device.

The AEI zeolite obtained by the manufacturing method of the present invention has a sufficient acid amount as an acid catalyst. The acid amount is 0.5 mmol/g or more and 3 mmol/g or less, and further 1 mmol/g or more and 2 mmol/g or less.

The amount of acid can be determined by ammonia TPD measurement of proton-type AEI zeolite with organic matter removed.

The AEI zeolite obtained by the production method of the present invention has a molar ratio of silanol to silicon (hereinafter also referred to as "SiOH/Si ratio") of 0.5 x ^10-2 or less. Ideal AEI zeolite does not contain silanol, but in reality, AEI zeolite contains silanol. Therefore, the SiOH/Si ratio can be more than 0 and less than 0.3 x ^10-2 , or even more than 0 and less than 0.2 x ^10-2 .

The amount of silanol can be determined by NMR measurement of ammonium-type AEI zeolite from which organic matter has been removed.

The AEI zeolite obtained by the manufacturing method of the present invention has high heat resistance and has little decrease in crystallinity before and after exposure to a hydrothermal atmosphere, and preferably has less decrease in crystallinity before and after exposure to a hydrothermal atmosphere compared to conventional AEI zeolite obtained using Y-type zeolite as a raw material. The degree of decrease in crystallinity due to exposure to a hydrothermal atmosphere can be indicated by the ratio of crystallinity after exposure to a hydrothermal atmosphere to the crystallinity before exposure to a hydrothermal atmosphere (hereinafter also referred to as "crystallization maintenance rate"), which can be determined by comparing the intensity of the XRD peak before and after exposure to a hydrothermal atmosphere.

The AEI zeolite obtained by the manufacturing method of the present invention can be used as a catalyst carrier or adsorbent. Furthermore, since the AEI zeolite obtained by the manufacturing method of the present invention contains at least one of copper and iron, it is expected that it can be used as a catalyst and even as a nitrogen oxide reduction catalyst.

The present invention can provide a manufacturing method for obtaining AEI zeolite without relying on structural transformation of crystalline aluminosilicate having a Y-type structure and without using fluorine. This can reduce the manufacturing cost compared to conventional manufacturing methods for AEI zeolite. Furthermore, the present invention can provide an industrial manufacturing method for AEI zeolite with reduced manufacturing costs.

Furthermore, the method for producing AEI zeolite of the present invention is suitable as a method for producing AEI zeolite having a SiO ₂ /Al ₂ O ₃ ratio of 100 or less, further 50 or less, and further 25 or less.

The present invention will be described in detail below with reference to examples. However, the present invention is not limited to these examples. Note that "ratios" are "molar ratios" unless otherwise specified.

(Identification of crystal structure)
The product was subjected to XRD measurement using a general X-ray diffraction device (product name: MXP-3, manufactured by Mac Science Co., Ltd.) under the following measurement conditions.

Radiation source: CuKα radiation (λ=1.5405Å)
Measurement mode: Step scan Scan condition: 0.04° per second
Divergence slit: 1.00 deg
Scattering slit: 1.00 deg
Receiving slit: 0.30 mm
Measurement time: 3.00 seconds Measurement range: 2θ = 3° to 43°
The obtained XRD pattern was compared with the XRD patterns in Table 1 of Patent Document 1 to identify the crystal structure.

(Composition Analysis)
The composition analysis was performed using an X-ray fluorescence analyzer (product name: RIX2100, manufactured by Rigaku Corporation). As a pretreatment, the product was fired at 600° C. for 1 hour. From the obtained analysis results, the SiO ₂ /Al ₂ O ₃ ratio of the product was obtained.

(SAR change rate)
The SAR change rate was calculated from the SiO ₂ /Al ₂ O ₃ ratio obtained by composition analysis according to the following formula.

SAR change rate (%)
= {1 - (SiO ₂ /Al ₂ O ₃ ratio of product)
/SiO ₂ /Al ₂ O ₃ ratio of raw material composition) × 100
(yield)
The yield of AEI zeolite was calculated from the following formula.

Yield (wt%) = (total weight of Al ₂ O ₃ and SiO ₂ in AEI zeolite)
/(Total weight _{of Al2O3 and SiO2 in the raw material composition)×100 The total weight of Al2O3 and SiO2 was determined} by measuring the Al content and converting it into _Al2O3 , and measuring the Si content and converting _{it into SiO2} .

(Solid recovery rate)
The solid recovery rate of the AEI zeolite was calculated from the following formula.
Solid recovery rate (%)
= (total weight of metals in AEI zeolite converted into oxide) ÷ (total weight of components other than water in raw material composition) × 100

(Silanol content)
The synthesized AEI zeolite was calcined in air at 600°C for 2 hours, and then the silanol content was measured by 1H MAS NMR. The conditions were as follows. Prior to the measurement, the sample was pretreated by holding it at 400°C for 5 hours under vacuum evacuation to dehydrate it. After the pretreatment, the sample was cooled to room temperature and collected under a nitrogen atmosphere and weighed. A general NMR device (device name: VXR-300S, manufactured by Varian) was used as the measuring device.

Resonance frequency: 300.0MHz
Pulse width: π/2
Measurement waiting time: 10 seconds Number of measurements: 32 Rotation frequency: 4 kHz
Shift criteria: TMS
From the obtained 1H MAS NMR spectrum, the peak assigned to the silanol group (peak at 2.0±0.5 ppm) was subjected to waveform separation, and its area intensity was obtained. From the obtained area intensity, the amount of silanol in the sample was calculated by the calibration curve method. The amount of silanol was calculated.

(Acid content)
The synthesized AEI zeolite was calcined in air at 600°C for 2 hours, and then measured by ammonia TPD (Temperature Programmed Desorption) method using BELCATII manufactured by Microtrack Bell Co., Ltd. Prior to the measurement, 0.05g of AEI zeolite was heated in helium at 500°C to remove adsorbed components, and then ammonia was saturated and adsorbed by passing a mixed gas of 99% helium and 1% ammonia at 100°C. Next, helium gas was passed through to remove ammonia remaining in the system. After removing ammonia, the amount of ammonia desorbed from the sample when treated under the following conditions was quantified, and the amount of acid was determined.
Atmosphere: Helium flow (flow rate 30 mL/min)
Heating rate: 10°C/min
Treatment temperature: 100°C to 700°C

(Average crystal size)
The crystal size and shape of the primary particles were observed using an electron microscope (device name: JSM-6390LV, manufactured by Hitachi Spectroscopy). When the primary particles were cubic crystals, the length of one side of the crystal was measured, and when the primary particles were tetragonal crystals, the length of the side of a square face was measured to determine the crystal size. The average crystal size was determined by randomly sampling 30 or more primary particles and averaging the measured values of the individual crystal sizes.

(Loose bulk density)
The powder sample was allowed to fall naturally through a sieve and filled into a container, and the bulk density was measured and taken as the loose bulk density. For the measurement, a powder property measuring device (device name: MULTI TESTER MT-1001, manufactured by Seishin Enterprise Co., Ltd.) was used.

Example 1
9.84 g of granular amorphous silicic acid calculated as _SiO2 , _0.37 g of aluminum sulfate calculated as _Al2O3 , 23.08 g of 21 wt% DEDMPOH, 3.35 g of sodium hydroxide, and 20.12 g of pure water were mixed to obtain a raw material composition having the following composition.

SiO ₂ /Al ₂ O ₃ =45
Na/SiO ₂ =0.56
_H2O / _SiO2 = 12.8
DEDMPOH/SiO ₂ =0.16
OH ⁻ /SiO ₂ =0.72
The (Si-Al) _Cry /(Si-Al) _Total of the raw material composition was 0% by weight.

The obtained raw material composition was sealed in a stainless steel autoclave. The autoclave was rotated and heated at 135°C for 120 hours to crystallize the raw material composition.

The resulting product was filtered, washed and dried overnight in air at 110° C. The resulting product was AEI type zeolite, SSZ-39, with a SiO ₂ /Al ₂ O ₃ ratio of 19. The yield was 45 wt %, the solids yield was 27% and the SAR conversion rate was 58%.
The results are shown in Table 1.

Example 2
A product was obtained in the same manner as in Example 1, except that the raw material composition had the following composition and the crystallization temperature was 150°C.

_SiO2 / _{Al2O3 =} 33
Na/SiO ₂ =0.56
_H2O / _SiO2 = 19.8
DEDMPOH/SiO ₂ =0.16
OH ⁻ /SiO ₂ =0.72
The (Si-Al) _Cry /(Si-Al) _Total of the raw material composition was 0% by weight.

The product obtained was AEI type zeolite, SSZ-39, with a SiO ₂ /Al ₂ O ₃ ratio of 15. The yield was 47% by weight, the solid content yield was 29%, and the SAR conversion rate was 55%. The results are shown in Table 1.

The average crystal size of the AEI zeolite in this example was 1.5 μm.

Example 3
11.82 g of granular amorphous silicic acid calculated as _SiO2 , _0.79 g of _aluminum sulfate calculated as _Al2O3 , 0.57 g of AEI zeolite ( _SiO2 / _Al2O3 ratio = 16, average particle size 3.1 μm), 11.72 g of 53 wt% DMDMPOH, 1.56 g of sodium hydroxide, 1.10 g of potassium hydroxide, and 30.00 g of pure water were mixed to obtain a raw material composition having the following composition.

SiO ₂ /Al ₂ O ₃ =25
Na/SiO ₂ =0.20
K/SiO ₂ =0.10
(Na+K)/SiO ₂ =0.30
K/Na = 0.50
H ₂ O/SiO ₂ =9.8
DMDMPOH/SiO ₂ =0.20
OH ⁻ /SiO ₂ =0.50
The (Si-Al) _Cry /(Si-Al) _Total of the raw material composition was 4.40% by weight.

The product was obtained in the same manner as in Example 1, except that the raw material composition was used and crystallization was carried out at 180°C for 48 hours.

The product obtained was AEI type zeolite, SSZ-39, with a SiO ₂ /Al ₂ O ₃ ratio of 12. The yield was 53% by weight, the solid content yield was 31%, and the SAR conversion rate was 52%. The results are shown in Table 1.

Example 4
A product was obtained in the same manner as in Example 3, except that the raw material composition used had the following composition.

SiO ₂ /Al ₂ O ₃ =25
Na/SiO ₂ =0.20
K/SiO ₂ =0.07
(Na+K)/SiO ₂ =0.27
K/Na = 0.35
H ₂ O/SiO ₂ =9.8
DMDMPOH/SiO ₂ =0.20
OH ⁻ /SiO ₂ =0.47
The (Si-Al) _Cry /(Si-Al) _Total of the raw material composition was 4.49% by weight.

The product obtained was AEI type zeolite, SSZ-39, with a SiO ₂ /Al ₂ O ₃ ratio of 13. The yield was 57% by weight, the solid content yield was 34%, and the SAR conversion rate was 48%. The results are shown in Table 1.

Example 5
A product was obtained in the same manner as in Example 3, except that the raw material composition used had the following composition.

SiO ₂ /Al ₂ O ₃ =25
Na/SiO ₂ =0.20
K/SiO ₂ =0.05
(Na+K)/SiO ₂ =0.25
K/Na=0.25
H ₂ O/SiO ₂ =9.8
DMDMPOH/SiO ₂ =0.20
OH ⁻ /SiO ₂ =0.45
The (Si-Al) _Cry /(Si-Al) _Total of the raw material composition was 4.40% by weight.

The product obtained was AEI type zeolite, SSZ-39, with a SiO ₂ /Al ₂ O ₃ ratio of 14. The yield was 59% by weight, the solid content yield was 37%, and the SAR conversion rate was 44%. The results are shown in Table 1.

Example 6
A product was obtained in the same manner as in Example 3, except that the raw material composition used had the following composition.

SiO ₂ /Al ₂ O ₃ =25
Na/SiO ₂ =0.18
K/SiO ₂ =0.07
(Na+K)/SiO ₂ =0.25
K/Na = 0.39
H ₂ O/SiO ₂ =9.8
DMDMPOH/SiO ₂ =0.20
OH ⁻ /SiO ₂ =0.45
The (Si-Al) _Cry /(Si-Al) _Total of the raw material composition was 4.40% by weight.

The product obtained was AEI type zeolite, SSZ-39, with a SiO ₂ /Al ₂ O ₃ ratio of 14. The yield was 59% by weight, the solid content yield was 37%, and the SAR conversion rate was 44%. The results are shown in Table 1.

Example 7
A product was obtained in the same manner as in Example 3, except that the raw material composition used had the following composition.

SiO ₂ /Al ₂ O ₃ =25
Na/SiO ₂ =0.24
K/SiO ₂ =0.03
(Na+K)/SiO ₂ =0.27
K/Na=0.13
H ₂ O/SiO ₂ =9.8
DMDMPOH/SiO ₂ =0.20
OH ⁻ /SiO ₂ =0.47
The (Si-Al) _Cry /(Si-Al) _Total of the raw material composition was 4.40% by weight.

The product obtained was AEI type zeolite, SSZ-39, with a SiO ₂ /Al ₂ O ₃ ratio of 14. The yield was 58% by weight, the solid content yield was 36%, and the SAR conversion rate was 44%. The results are shown in Table 1.

Example 8
A product was obtained in the same manner as in Example 3, except that the raw material composition used had the following composition.

SiO ₂ /Al ₂ O ₃ =31
Na/SiO ₂ =0.22
K/SiO ₂ =0.05
(Na+K)/SiO ₂ =0.27
K/Na=0.23
H ₂ O/SiO ₂ =9.8
DMDMPOH/SiO ₂ =0.20
OH ⁻ /SiO ₂ =0.47
The (Si-Al) _Cry /(Si-Al) _Total of the raw material composition was 4.40% by weight.

The product obtained was AEI type zeolite, SSZ-39, with a SiO ₂ /Al ₂ O ₃ ratio of 17. The yield was 56% by weight, the solid content yield was 35%, and the SAR conversion rate was 45%. The results are shown in Table 1.

Example 9
A product was obtained in the same manner as in Example 3, except that the raw material composition used had the following composition.

_SiO2 / _{Al2O3 =} 36
Na/SiO ₂ =0.24
K/SiO ₂ =0.09
(Na+K)/SiO ₂ =0.33
K/Na = 0.38
H ₂ O/SiO ₂ =9.8
DMDMPOH/SiO ₂ =0.16
OH ⁻ /SiO ₂ =0.49
The (Si-Al) _Cry /(Si-Al) _Total of the raw material composition was 4.40% by weight.

The product obtained was AEI type zeolite, SSZ-39, with a SiO ₂ /Al ₂ O ₃ ratio of 17. The yield was 49% by weight, the solid content yield was 32%, and the SAR conversion rate was 53%. The results are shown in Table 1.

Example 10
A product was obtained in the same manner as in Example 3, except that the raw material composition used had the following composition.

SiO ₂ /Al ₂ O ₃ =43
Na/SiO ₂ =0.20
K/SiO ₂ =0.09
(Na+K)/SiO ₂ =0.29
K/Na = 0.45
H ₂ O/SiO ₂ =9.8
DMDMPOH/SiO ₂ =0.20
OH ⁻ /SiO ₂ =0.49
The (Si-Al) _Cry /(Si-Al) _Total of the raw material composition was 4.40% by weight.

The product obtained was AEI type zeolite, SSZ-39, with a SiO ₂ /Al ₂ O ₃ ratio of 18. The yield was 43% by weight, the solid content yield was 26%, and the SAR conversion rate was 58%. The results are shown in Table 1.

Example 11
_12.88 g of amorphous aluminosilicate ( _SiO2 / _Al2O3 ratio = ₂₇ ), 0.57 g of AEI type zeolite ( _SiO2 / _Al2O3 ratio = 16, average particle size 3.1 μm), 6.42 g of DMDMPOH, 0.94 g of sodium hydroxide, 0.45 g of potassium hydroxide, and 36.48 g of pure water were mixed to obtain a raw material composition having the following composition.

SiO ₂ /Al ₂ O ₃ =27
Na/SiO ₂ =0.13
K/SiO ₂ =0.03
(Na+K)/SiO ₂ =0.16
K/Na=0.23
H ₂ O/SiO ₂ =9.8
DMDMPOH/SiO ₂ =0.20
OH ⁻ /SiO ₂ =0.36
The (Si-Al) _Cry /(Si-Al) _Total of the raw material composition was 4.31% by weight.

The product was obtained in the same manner as in Reference Example 1-1, except that the raw material composition was used and crystallization was carried out at 170°C for 168 hours.

The product obtained was AEI type zeolite, SSZ-39, with a SiO ₂ /Al ₂ O ₃ ratio of 18. The yield was 69% by weight, the solid content yield was 42%, and the SAR conversion rate was 33%. The results are shown in Table 1.

Example 12
7.84 g of amorphous aluminosilicate (SiO ₂ /Al ₂ O ₃ ratio=33), 16.92 g of 21 wt % DEDMPOH, 2.36 g of sodium hydroxide, and 29.88 g of pure water were mixed to obtain a raw material composition having the following composition.

_SiO2 / _{Al2O3 =} 33
Na/SiO ₂ =0.56
_H2O / _SiO2 = 20
DEDMPOH/SiO ₂ =0.16
OH ⁻ /SiO ₂ =0.72
The (Si-Al) _Cry /(Si-Al) _Total of the raw material composition was 0% by weight.

The obtained raw material composition was sealed in a stainless steel autoclave. The autoclave was rotated and heated at 150°C for 72 hours to crystallize the raw material composition.

The resulting product was filtered, washed, and dried overnight at 110° C. in air. The resulting product was AEI zeolite, SSZ-39, with a SiO ₂ /Al ₂ O ₃ ratio of 15. The yield was 49% by weight, the solid recovery rate was 29%, and the SAR conversion rate was 54%. The results are shown in Table 1.

The average crystal size of the AEI zeolite in this example was 0.85 μm.

Example 13
_12.47 g of amorphous aluminosilicate ( _SiO2 / _Al2O3 ratio = ₃₉ ), 0.73 g of AEI type zeolite ( _SiO2 / _Al2O3 ratio = 18, average particle size 3.1 μm), 11.82 g of 53 wt% DMDMPOH, 1.88 g of sodium hydroxide, 0.56 g of potassium hydroxide, and 30.27 g of pure water were mixed to obtain a raw material composition having the following composition.

SiO ₂ /Al ₂ O ₃ =37
Na/SiO ₂ =0.24
K/SiO ₂ =0.05
(Na+K)/SiO ₂ =0.29
K/Na = 0.21
_H2O / _SiO2 = 10
DMDMPOH/SiO ₂ =0.20
OH ⁻ /SiO ₂ =0.49
The (Si-Al) _Cry /(Si-Al) _Total of the raw material composition was 4.40% by weight.

The product was obtained in the same manner as in Example 1, except that the raw material composition was used and crystallization was carried out at 170°C for 36 hours.

The obtained product was AEI type zeolite, SSZ-39, with a SiO ₂ /Al ₂ O ₃ ratio of 19. The SiO ₂ /Al ₂ O ₃ ratio measured by ICP method was also 19. The yield was 53% by weight, the solid recovery rate was 31%, and the SAR conversion rate was 50%. The results are shown in Table 1.

The silanol amount of the AEI zeolite of this example was SiOH/Si=0.1×10 ⁻² .

The acid amount in this example was 1.72 mmol/g.

Example 14
_12.38 g of amorphous aluminosilicate ( _SiO2 / _Al2O3 ratio = ₄₁ ), 0.73 g of AEI type zeolite ( _SiO2 / _Al2O3 ratio = 18, average particle size 3.1 μm), 11.77 g of 53 wt% DMDMPOH, 1.73 g of sodium hydroxide, 1.00 g of potassium hydroxide, and 30.13 g of pure water were mixed to obtain a raw material composition having the following composition.

SiO ₂ /Al ₂ O ₃ =39
Na/SiO ₂ =0.22
K/SiO ₂ =0.09
(Na+K)/SiO ₂ =0.31
K/Na = 0.41
_H2O / _SiO2 = 10
DMDMPOH/SiO ₂ =0.20
OH ⁻ /SiO ₂ =0.51
The (Si-Al) _Cry /(Si-Al) _Total of the raw material composition was 4.40% by weight.

The product was obtained in the same manner as in Example 1, except that the raw material composition was used and crystallization was carried out at 170°C for 24 hours.

The product obtained was AEI type zeolite, SSZ-39, with a SiO ₂ /Al ₂ O ₃ ratio of 18. The yield was 48% by weight, the solid recovery rate was 27%, and the SAR conversion rate was 55%. The results are shown in Table 1.

Example 15
12.62 _g of amorphous aluminosilicate ( _SiO2 / _Al2O3 ratio = ₂₉ ), 0.74 g of AEI type zeolite ( _SiO2 / _Al2O3 ratio = 18, average particle size 3.1 μm), 11.80 g of 53 wt% DMDMPOH, 1.58 g of sodium hydroxide, 0.78 g of potassium hydroxide, and 30.22 g of pure water were mixed to obtain a raw material composition having the following composition.

SiO ₂ /Al ₂ O ₃ =28
Na/SiO ₂ =0.20
K/SiO ₂ =0.07
(Na+K)/SiO ₂ =0.27
K/Na = 0.35
_H2O / _SiO2 = 10
DMDMPOH/SiO ₂ =0.20
OH ⁻ /SiO ₂ =0.47
The (Si-Al) _Cry /(Si-Al) _Total of the raw material composition was 4.40% by weight.

The product was obtained in the same manner as in Example 1, except that the raw material composition was used and crystallization was carried out at 170°C for 48 hours.

The product obtained was AEI type zeolite, SSZ-39, with a SiO ₂ /Al ₂ O ₃ ratio of 15. The yield was 57% by weight, the solid recovery rate was 35%, and the SAR conversion rate was 46%. The results are shown in Table 1.

The average crystal size of the AEI zeolite in this example was 1.8 μm.

Example 16 12.39 _g of amorphous aluminosilicate ( _SiO2 / _Al2O3 ratio = ₄₁ ), 0.73 g of AEI type zeolite ( _SiO2 / _Al2O3 ratio = 18, average particle size 3.1 μm), 11.77 g of 53 wt% DMDMPOH, 1.71 g of sodium hydroxide, 1.00 g of potassium hydroxide, and 30.13 g of pure water were mixed to obtain a raw material composition having the following composition.

SiO ₂ /Al ₂ O ₃ =39
Na/SiO ₂ =0.22
K/SiO ₂ =0.09
(Na+K)/SiO ₂ =0.31
K/Na = 0.41
_H2O / _SiO2 = 10
DMDMPOH/SiO ₂ =0.20
OH ⁻ /SiO ₂ =0.51
The (Si-Al) _Cry /(Si-Al) _Total of the raw material composition was 4.40% by weight.

The product was obtained in the same manner as in Example 1, except that the raw material composition was used and crystallization was carried out at 170°C for 36 hours.

The product obtained was AEI type zeolite, SSZ-39, with a SiO ₂ /Al ₂ O ₃ ratio (XRF) of 17. The yield was 47% by weight, the solid recovery rate was 27%, and the SAR conversion rate was 55%. The results are shown in Table 1.

The loose bulk density of the AEI zeolite of this example was 0.34 g/ ^cm3 .

Comparative Example 1
With reference to the examples of U.S. Patent No. 5,958,370, AEI zeolite was produced by structural conversion of crystalline aluminosilicate having a Y-type structure. That is, 3.28 g of sodium silicate aqueous solution, calculated as _SiO2 , 0.82 g of Y-type zeolite ( _SiO2 / _{Al2O3 ratio} =6), 8.69 g of 21 wt% DEDMPOH aqueous solution, and 36.28 g of pure water were mixed to obtain a raw material composition having the following composition.

SiO ₂ /Al ₂ O ₃ =50
Na/SiO ₂ =0.56
H ₂ O/SiO ₂ =44.8
DEDMPOH/SiO ₂ =0.16
OH ⁻ /SiO ₂ =0.72
The (Si-Al) _Cry /(Si-Al) _Total of the raw material composition was 11.50% by weight.

The resulting raw material composition was sealed in a stainless steel autoclave, and the autoclave was heated at 135°C for 168 hours while rotating to obtain the product.

The resulting product was filtered, washed, and dried overnight in air at 110° C. The resulting product was AEI zeolite, SSZ-39, with a SiO ₂ /Al ₂ O ₃ ratio of 19. The yield was 40% by weight, the solid recovery rate was 24%, and the SAR conversion rate was 62%. The results are shown in Table 1.

Comparative Example 2
6.47 g of sodium silicate aqueous solution calculated as _SiO2 , 1.61 g of Y-type zeolite ( _SiO2 / _Al2O3 ratio=6), 17.15 g of 21 _wt % DEDMPOH, and 16.13 g of pure water were mixed to obtain a raw material composition having the following composition.

SiO ₂ /Al ₂ O ₃ =50
Na/SiO ₂ =0.56
_H2O / _SiO2 = 19.8
DEDMPOH/SiO ₂ =0.16
OH/ _SiO2 =0.72
The (Si-Al) _Cry /(Si-Al) _Total of the raw material composition was 11.50% by weight.

The resulting raw material composition was sealed in a stainless steel autoclave, and the autoclave was heated at 135°C for 168 hours while rotating to obtain the product.

The product was filtered, washed, and dried overnight at 110° C. in air. The product obtained was AEI type zeolite, SSZ-39, with a SiO ₂ /Al ₂ O ₃ ratio of 16. The yield was 35 wt %, the solid recovery rate was 21%, and the SAR conversion rate was 68%. The results are shown in Table 1.

The average crystal size of the AEI zeolite in this comparative example was 0.99 μm.

Comparative Example 3
_2.75 g of sodium silicate aqueous solution (SiO2 equivalent), 2.78 g of Y _- type zeolite ( _SiO2 / _Al2O3 ratio = 29), 7.42 g of 34 wt% DMDMPOH, 0.61 g of sodium hydroxide, and 36.82 g of pure water were mixed to obtain a raw material composition having the following composition.

SiO ₂ /Al ₂ O ₃ = 60
Na/SiO ₂ =0.49
_H2O / _SiO2 = 29.8
DMDMPOH/SiO ₂ =0.18
OH/ _SiO2 =0.67
The (Si-Al) _Cry /(Si-Al) _Total of the raw material composition was 42.69% by weight.

The resulting raw material composition was sealed in a stainless steel autoclave, and the autoclave was heated at 145°C for 94 hours while rotating to obtain the product.

The product was filtered, washed and dried overnight at 110° C. in air. The product obtained was AEI type zeolite, SSZ-39, with a SiO ₂ /Al ₂ O ₃ ratio of 18. The yield was 32% by weight, the solid recovery rate was 19%, and the SAR conversion rate was 70%. The results are shown in Table 1.

Comparative Example 4
A product was obtained in the same manner as in Example 1, except that the crystallization time was 75 hours. The product obtained was only amorphous, and no AEI zeolite was obtained. The results are shown in Table 1.

It was confirmed that the manufacturing method of the present invention can produce AEI zeolite from amorphous aluminum compounds without structural transformation of Y zeolite. Furthermore, it was confirmed that AEI zeolite can be produced from amorphous aluminum compounds even when a trace amount of crystalline aluminosilicate is contained. Furthermore, in the manufacturing method of the present invention, the SAR change rate between the raw material composition and AEI zeolite was 60% or less, further 50% or less, and further 45% or less. From this, it was confirmed that the silica source and alumina source used as raw materials were used efficiently compared to the manufacturing method of AEI zeolite by structural transformation of Y zeolite as shown in the comparative example.

The production method of the present invention can be utilized as a method for industrially producing AEI zeolite, in particular, as a method for industrially producing AEI zeolite having a SiO ₂ /Al ₂ O ₃ ratio of 100 or less, further 50 or less.

Claims (4)

An AEI zeolite having a loose bulk density of 0.1 g/cm ³ or more and 0.5 g/cm ³ or less , and a molar ratio of silica to alumina (SiO ₂ /Al ₂ O ₃ ratio) of 15 or more and 100 or less . The AEI zeolite according to claim 1, wherein the acid amount is 1 mmol/g or more and 2 mmol/g or less. The AEI zeolite according to claim 1 or 2, having an average crystal size of 0.5 μm or more and 2 μm or less. 3. The AEI zeolite according to claim 1, wherein the molar ratio of silanol to silicon is 0.5×10 ⁻² or less.