JP2018140887A - Afx-type zeolite comprising phosphorus and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a zeolite with small pores that has a higher heat resistance than a conventional zeolite with small pores.SOLUTION: There is provided an AFX-type zeolite comprising phosphorus. Such an AFX-type zeolite is preferably obtained by a production method including a crystallization step of crystallizing a composition comprising a silica source, an alumina source, a phosphonium cation source and an ammonium cation source.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an AFX zeolite and a method for producing the same. More specifically, the present invention relates to an AFX type zeolite suitable for a catalyst or a substrate thereof and a method for producing the same.

  The AFX zeolite is a so-called small-pore zeolite having an oxygen 8-membered ring structure, which is a crystalline aluminosilicate that is expected for various catalyst applications such as an olefin production catalyst and a selective catalytic reduction catalyst. There is no natural compound of AFX type zeolite, and it is synthesized by a hydrothermal reaction using an organic structure directing agent.

  As an organic structure directing agent, for example, AFX zeolite synthesized by using 1,4-bis (azoniabicyclo [2.2.2] octane) butyl cation (Patent Document 1), 1,4-bis (azabicyclo [2] 2.2.2] AFX-type zeolite synthesized using octane) butyl cation (Patent Document 2), and further reported that AFX-type zeolite can be synthesized by using various ammonium cations including the above two types. (Non-Patent Document 1).

  In addition to these, AFX zeolite synthesized using 1,3-bis (1-adamantyl) imidazolium cation (non-patent document 2), N, N, N ′, N ′ as organic structure directing agent -AFX type zeolite synthesized using tetraethylbicyclo [2.2.2] octene-2,3: 5,6-dipyrrolidinium cation has been reported (Non-patent Document 3).

  By the way, zeolite used as an olefin production catalyst or a selective catalytic reduction catalyst is required to be resistant to deterioration at high temperatures, so-called heat resistance. The AFX zeolite that has been reported so far exhibits relatively high heat resistance among small-pore zeolites, but there are applications that require higher heat resistance in these catalyst applications.

US Pat. No. 4,508,837 US Pat. No. 5,194,235

“Chemistry of Materials” American Chemical Society, (USA), 1996, Vol. 8, p. 2409-2411 “Microporous and Mesoporous Materials” Elsevier, (Netherlands), 2010, Vol. 130, p. 255-265 "International Symposium on Zeolite and Microporous Crystals, Proceedings", 2015, RRR2-018

  An object of the present invention is to provide a small-pore zeolite having higher heat resistance than conventional small-pore zeolite. Furthermore, another object of the present invention is to provide a method for producing such a zeolite.

  The present inventors examined a small pore zeolite and a production method thereof. As a result, it was found that heat resistance is increased by adding phosphorus to the AFX zeolite. Furthermore, it has been found that such an AFX-type zeolite can be obtained by a production method in which crystallization and phosphorus modification are simultaneously performed by using a structure directing agent that is easily available industrially.

That is, the gist of the present invention is as follows.
[1] An AFX zeolite containing phosphorus.
[2] The AFX zeolite according to [1], wherein the phosphorus is contained in the pores.
[3] The AFX zeolite according to [1] or [2] above, wherein the molar ratio of silica to alumina is 9 or more and 20 or less.
[4] The AFX zeolite according to any one of [1] to [3], wherein a molar ratio of the phosphorus to the skeleton metal is 0.001 or more and 0.1 or less.
[5] The method according to any one of [1] to [4], further including a crystallization step of crystallizing a composition containing a silica source, an alumina source, a phosphonium cation source, and an ammonium cation source. A method for producing AFX zeolite.
[6] The method according to [5], wherein the phosphonium cation source is at least one member selected from the group consisting of tetraethylphosphonium hydroxide, tetraethylphosphonium bromide, tetraethylphosphonium chloride, and tetraethylphosphonium iodide. .
[7] The ammonium cation source is 1,4-bis (1-azabicyclo [2.2.2] octane) butyl dioxide, 1,4-bis (1-azabicyclo [2.2.2] octane) butyl. In the group consisting of dichloride, 1,4-bis (1-azabicyclo [2.2.2] octane) butyl dibromide, and 1,4-bis (1-azabicyclo [2.2.2] octane) butyl diiodide The production method according to [5] or [6] above, wherein the production method is at least one kind.
[8] The production method according to any one of [5] to [7], wherein the molar ratio of the ammonium cation to the total of the phosphonium cation and the ammonium cation is 0.01 or more and less than 1.0. .
[9] The method according to any one of [5] to [8], wherein the silica source and the alumina source are crystalline aluminosilicates.
[10] The production method according to any one of [5] to [9], wherein the silica source and the alumina source are FAU type zeolite.

  According to the present invention, it is possible to provide a small-pore zeolite having higher heat resistance than conventional small-pore zeolite. Furthermore, this invention can provide the manufacturing method of such a zeolite.

XRD pattern of AFX zeolite of Example 1 Scanning electron microscope observation of the AFX zeolite of Example 1

  Hereinafter, the AFX zeolite of the present invention will be described in detail.

  The AFX zeolite of the present invention has an AFX structure. The AFX structure is a crystal structure that becomes an AFX structure with a structure code defined by the International Zeolite Society. The crystal structure of the zeolite includes a powder X-ray diffraction (hereinafter also referred to as “XRD”) pattern described in Collection of simulated XRD powder patterns for zeolitics, Fifth revised edition (2007), and a website ht of the IZA Structure Committee p. // www. isa-structure. It can be identified by comparison with any of the XRD patterns described in Zeolite Framework Types of org / databases /.

  The AFX zeolite of the present invention is a crystalline aluminosilicate having an AFX structure. In crystalline aluminosilicate, the skeletal metal (hereinafter also referred to as “T atom”) is aluminum (Al) and silicon (Si), and has a three-dimensional skeletal structure composed of a network of these skeletal metal and oxygen (O). Have. Therefore, zeolite related substances such as aluminophosphate and silicoaluminophosphate having an AFX structure and a skeleton structure composed of a network containing phosphorus (P) in the T atom are different from the AFX zeolite of the present invention. .

  The AFX zeolite of the present invention contains phosphorus. This improves the thermal stability of aluminum constituting the skeleton metal, and increases the heat resistance of the AFX zeolite of the present invention, as compared with conventional small pore zeolites such as AFX zeolite not containing phosphorus. In addition to this, the acid sites of the zeolite are modified with phosphorus to obtain an acid strength suitable for a specific catalytic reaction. For this reason, it is suitable as a base material for various catalysts such as catalysts for producing lower olefins from alcohols and ketones, cracking catalysts, dewaxing catalysts, isomerization catalysts, and nitrogen oxide reduction catalysts, and various catalysts.

  On the other hand, when phosphorus is not contained in the AFX type zeolite of the present invention, the heat stability of aluminum constituting the skeleton metal is not improved, so that excellent heat resistance cannot be obtained. In addition to this, the acid strength of the AFX zeolite may become too strong, and side reactions are likely to occur. Therefore, it is difficult to use as a base material for the above-mentioned various catalysts and various catalysts.

  Phosphorus is contained other than the AFX zeolite framework, that is, other than T atoms. For example, phosphorus is contained in the pores of the AFX zeolite, and particularly preferably contained in the oxygen 8-membered ring pores. As described above, the T atom in the AFX zeolite of the present invention is a skeletal metal contained in the skeleton, that is, Si and Al. Examples of a method for confirming that phosphorus is contained as other than T atoms include a method for confirming that phosphorus is present as an organic phosphorus compound by measuring NMR of the phosphorus compound in the AFX zeolite. It is done.

  The state of phosphorus contained in the AFX zeolite of the present invention is at least one of phosphate ions and phosphorus compounds. Moreover, as a form containing phosphorus, the form fixed to AFX type zeolite without a chemical bond can be mentioned, for example.

In the AFX zeolite of the present invention, the molar ratio of silica to alumina (hereinafter also referred to as “SiO ₂ / Al ₂ O ₃ ratio”) is 5 or more, and preferably 9 or more. When the SiO ₂ / Al ₂ O ₃ ratio is 5 or more, the AFX zeolite of the present invention has sufficient heat resistance for use in applications such as catalysts. On the other hand, if the SiO ₂ / Al ₂ O ₃ ratio is 100 or less, preferably 30 or less, more preferably 20 or less, the AFX zeolite of the present invention has a sufficient amount of acid sites as a catalyst. A particularly preferable SiO ₂ / Al ₂ O ₃ ratio is 9 or more and 20 or less. The composition of the AFX zeolite of the present invention can be measured by the ICP method.

  The AFX type zeolite of the present invention preferably contains phosphorus in the pores. That is, the AFX type zeolite of the present invention preferably contains phosphorus at an acid site, that is, in the vicinity of Al which is a T atom. This makes it easier to further improve the thermal stability of aluminum constituting the skeleton metal, and the heat resistance is higher than that of small pore zeolite that does not contain phosphorus in the pores. In addition, modification of the acid sites with phosphorus is more easily performed, and the above-described various catalysts and base materials for various catalysts are more easily used.

  The molar ratio of phosphorus to T atom (hereinafter also referred to as “P / T ratio”) in the AFX zeolite of the present invention is 0.1 or less, further 0.05 or less, and further 0.02 or less. Is mentioned. If it exceeds 0.1, the pores of the AFX zeolite are likely to be blocked by phosphorus. Therefore, it becomes difficult to use the pores effectively for catalytic reaction and the like. The P / T ratio is preferably 0.0005 or more, more preferably 0.001 or more. When the P / T ratio is 0.001 or more, the heat resistance of the AFX zeolite is higher than that when it is less than 0.001. Particularly preferred P / T ratio is 0.001 or more and 0.1 or less.

  The AFX zeolite of the present invention preferably has a molar ratio of phosphorus to Al as a T atom (hereinafter also referred to as “P / Al ratio”) of 0.50 or less. When P / Al is 0.50 or less, an AFX zeolite having a sufficient amount of acid sites required for a catalyst and sufficient heat resistance for use as a catalyst is obtained. Further, Al as a T atom functions as an acid point. When the P / Al ratio is 0.005 or more, preferably 0.01 or more, an AFX zeolite having a large amount of Al as an acid point exhibiting catalytic activity is obtained. From the viewpoint of improving catalytic activity and heat resistance, the P / Al ratio is particularly preferably 0.005 or more and 0.5 or less.

  In addition, it is preferable that the AFX zeolite of the present invention does not substantially contain fluorine (F), that is, the fluorine content is 0 ppm. Generally, the fluorine contained in a zeolite originates from a raw material. Zeolite obtained using a compound containing fluorine as a raw material tends to be expensive to produce. Considering the measurement limit of the measurement value obtained by a usual composition analysis method such as lanthanum-alizarin complexone spectrophotometry, the fluorine content of the AFX zeolite of the present invention is 0 ppm or more and 100 ppm or less, more preferably 0 ppm or more and 50 ppm or less. I just need it.

  The AFX zeolite of the present invention can be composed of a plurality of crystal particles. The average diameter of crystal grains (hereinafter also referred to as “average crystal grain diameter”) is preferably 20 μm or less, and more preferably 10 μm or less. When the average crystal grain size is 20 μm or less, the reactivity is further improved as compared with the case where the average crystal grain size exceeds 20 μm, and thus the catalyst performance is further improved. In the present invention, the diameter of crystal grains (hereinafter also referred to as “crystal grain diameter”) can be confirmed by observation with a scanning electron microscope (hereinafter also referred to as “SEM”). That is, the crystal particles of the AFX zeolite of the present invention are the smallest unit crystal particles that can be observed using an SEM and have a hexagonal column shape in which hexagonal frustums are connected to both ends. The crystal grain size can be obtained by measuring the distance between two points farthest from each other contained in the crystal grain. The average crystal grain size can be obtained by arithmetically averaging the crystal grain sizes of ten crystal grains randomly extracted from the SEM image.

  Next, the manufacturing method of the AFX type zeolite of this invention is demonstrated.

  The AFX-type zeolite of the present invention comprises a crystallization step of crystallizing a composition containing a silica source, an alumina source, a phosphonium cation source and an ammonium cation source (hereinafter also referred to as “raw material composition”). can get.

  In the crystallization step, the raw material composition containing the phosphonium cation source is crystallized. The phosphonium cation not only functions as a structure directing agent (hereinafter also referred to as “SDA”) for deriving AFX zeolite, but also serves as a supply source of phosphorus. Phosphorus can be contained simultaneously with crystallization of the AFX type zeolite. Thereby, a post-treatment step for modifying phosphorus after the crystallization step is not essential. Furthermore, since the phosphonium cation source is not a special compound, it can be obtained from a general distribution channel. Since the phosphonium cation source can be used as SDA, it is possible to greatly reduce the amount of expensive SDA used which is essential in the conventional method for producing AFX zeolite.

  Examples of the phosphonium cation source include compounds containing a phosphonium cation, and at least one member selected from the group consisting of phosphonium cation sulfates, nitrates, halides and hydroxides. The phosphonium cation is preferably at least one of a tetraethylphosphonium cation (hereinafter also referred to as “TEP”) and a tetramethylphosphonium cation, and more preferably a TEP. When the phosphonium cation is TEP, it becomes easier to obtain an AFX zeolite containing phosphorus as compared with the case of being a tetramethylphosphonium cation.

  As particularly preferred phosphonium cation sources, tetraethylphosphonium hydroxide (hereinafter also referred to as “TEPOH”), tetraethylphosphonium bromide (hereinafter also referred to as “TEPBr”), and tetraethylphosphonium chloride (hereinafter also referred to as “TEPCl”). , And tetraethylphosphonium iodide (hereinafter also referred to as “TEPI”). By using these substances as the phosphonium cation source, it becomes easier to obtain an AFX type zeolite containing phosphorus as compared to the case of using a substance other than these substances. TEPOH can be mentioned as a particularly preferred phosphonium cation source because it is a general-purpose compound and its production cost is low.

  The raw material composition contains an ammonium cation source. The ammonium cation source functions as SDA to derive AFX type zeolite. The coexistence of an ammonium cation source and a phosphonium cation source as SDA in the raw material composition can not only reduce the amount of expensive ammonium cation source used, but in addition to this, the ratio of the phosphonium cation source and the ammonium cation source can be reduced. The amount of phosphorus contained in the AFX zeolite can be adjusted. Examples of the ammonium cation source include compounds containing an ammonium cation, and at least one member selected from the group consisting of ammonium cation sulfates, nitrates, halides, and hydroxides. The ammonium cation includes 1,4-bis (1-azabicyclo [2.2.2] octane) butyl cation, 1,4-bis (azoniabicyclo [2.2.2] octane) butyl cation, 1,3-bis ( 1-adamantyl) imidazolium cation and at least one of the group consisting of N, N, N ′, N′-tetraethylbicyclo [2.2.2] octene-2,3: 5,6-dipyrrolidinium cation A seed can be mentioned, and 1,4-bis (1-azabicyclo [2.2.2] octane) butyl cation is particularly preferable. When the ammonium cation is any of these ammonium cations, it becomes easier to obtain an AFX zeolite containing phosphorus as compared to a case other than these ammonium cations.

As a particularly preferred ammonium cation source, 1,4-bis (1-azabicyclo [2.2.2] octane) butyl dioxide (hereinafter also referred to as “[Dab-4] ²⁺ (OH ⁻ ) ₂ ”), 1 , 4-bis (1-azabicyclo [2.2.2] octane) butyl dichloride, 1,4-bis (1-azabicyclo [2.2.2] octane) butyl dibromide, and 1,4-bis (1 -At least one member selected from the group consisting of azabicyclo [2.2.2] octane) butyl diiodide, and [Dab-4] ²⁺ (OH ⁻ ) ₂ . When the ammonium cation source is any of these substances, an AFX zeolite containing phosphorus can be easily obtained as compared with the case where the ammonium cation source is other than these substances.

  The silica source and the alumina source contained in the raw material composition are preferably crystalline aluminosilicate (zeolite). Crystalline aluminosilicate has a regular crystal structure. When crystalline aluminum silicate is treated in the presence of a structure directing agent, it is considered that crystallization proceeds while maintaining regularity of the crystal structure. Therefore, when the silica source and the alumina source are separate compounds, or the silica source and the alumina source are crystalline aluminosilicate, compared with the case where the silica source and the alumina source are non-crystalline compounds, the AFX type Zeolite crystallizes more efficiently.

  In order to easily obtain a single-phase AFX zeolite, the crystalline aluminosilicate is preferably FAU-type zeolite, more preferably at least one of X-type zeolite and Y-type zeolite, and further Y-type zeolite.

The SiO ₂ / Al ₂ O ₃ ratio of the crystalline aluminosilicate is 1.25 or more, more preferably 10 or more, and further 20 or more. On the other hand, the SiO ₂ / Al ₂ O ₃ ratio is 100 or less, further 50 or less, and further 40 or less. A preferred SiO ₂ / Al ₂ O ₃ ratio of crystalline aluminosilicate is 10 or more and 50 or less, and further 20 or more and 40 or less.

The cation type of the crystalline aluminosilicate contained in the raw material composition is arbitrary. The cation type is preferably at least one selected from the group consisting of sodium type (Na type), proton type (H ⁺ type) and ammonium type (NH ₄ type), and more preferably a proton type.

  The raw material composition may not contain a silica source or an alumina source other than the crystalline aluminosilicate. From the viewpoint of increasing the efficiency of crystallization of the AFX zeolite, the raw material composition preferably does not contain an amorphous silica source and an alumina source, and the silica source and the alumina source are more preferably only crystalline aluminosilicate. preferable.

  The raw material composition may contain an alkali source and water in addition to a silica source, an alumina source, a phosphonium cation source and an ammonium cation source.

  Examples of the alkali source include a hydroxide containing an alkali metal. More specifically, it is a hydroxide containing at least one selected from the group consisting of lithium, sodium, potassium, rubidium and cesium, further a hydroxide containing at least one of sodium or potassium, and further It is a hydroxide containing sodium. Further, when the silica source and the alumina source contain an alkali metal, the alkali metal can also be used as the alkali source.

  Pure water may be used as the water, but each raw material described above may contain water and be used as an aqueous solution.

The molar ratio (SiO ₂ / Al ₂ O ₃ ratio) of silica to alumina in the raw material composition is 10 or more, and further 20 or more. On the other hand, the SiO ₂ / Al ₂ O ₃ ratio is 100 or less, further 50 or less, and further 40 or less. A preferable SiO ₂ / Al ₂ O ₃ ratio is 10 or more and 50 or less, and further 20 or more and 40 or less.

The molar ratio of the phosphonium cation to the silica of the raw material composition (hereinafter also referred to as “P-SDA / SiO ₂ ratio”) is preferably 0.01 or more, more preferably 0.05 or more. When the P-SDA / SiO ₂ ratio is 0.01 or more, phosphorus is easily contained in the obtained AFX-type zeolite. When the P-SDA / SiO ₂ ratio is 0.5 or less, and further 0.3 or less, the effect of improving heat resistance due to the phosphorus content is easily obtained.

The molar ratio of the ammonium cation to the silica of the raw material composition (hereinafter also referred to as “N-SDA / SiO ₂ ratio”) is 0.001 or more, and further 0.01 or more. On the other hand, an ammonium cation source containing 1,4-bis (1-azabicyclo [2.2.2] octane) butyl cation or the like is an expensive compound compared to a phosphonium cation source containing TEP or the like. When the / SiO ₂ ratio is 0.5 or less, and further 0.3 or less, a single-phase AFX zeolite can be obtained while suppressing the production cost.

The raw material composition contains a phosphonium cation and an ammonium cation as SDA. Therefore, the molar ratio of all SDA to the silica of the raw material composition (hereinafter also referred to as “SDA / SiO ₂ ratio”) exceeds zero. Furthermore, the SDA / SiO ₂ ratio is preferably 0.10 or more, more preferably 0.15 or more. However, if the amount of SDA is too large, the production cost of AFX zeolite is too high. Therefore, the SDA / SiO ₂ ratio is preferably 0.5 or less, more preferably 0.2 or less.

  The ratio of the phosphonium cation and the ammonium cation in the raw material composition can be set to any ratio depending on the phosphorus content of the target AFX zeolite. The molar ratio of the ammonium cation to the total of the phosphonium cation and ammo cation (hereinafter also referred to as “N-SDA / SDA ratio”) is 0.01 or more and less than 1.0. In the manufacturing method of the present invention, the N-SDA / SDA ratio is 0.01 or more and 0.9 or less, and further 0.01 or more and 0.1 or less, so that the manufacturing method can further reduce the manufacturing cost. Can do.

The molar ratio of the alkali metal to silica of the raw material composition (hereinafter also referred to as “alkali / SiO ₂ ratio”) is preferably 1 or less. When the alkali / SiO ₂ ratio is 1 or less, an AFX zeolite having a high SiO ₂ / Al ₂ O ₃ ratio is easily obtained. In order to obtain an AFX type zeolite having a higher SiO ₂ / Al ₂ O ₃ ratio, the alkali / SiO ₂ ratio is preferably 0.8 or less, more preferably 0.6 or less. The alkali / SiO ₂ ratio of the raw material composition is 0.1 or more, and further 0.2 or more. A particularly preferable alkali / SiO ₂ ratio is 0.2 or more and 1.0 or less.

The molar ratio of OH to silica (hereinafter also referred to as “OH / SiO ₂ ratio”) is preferably 1.0 or less. When the OH / SiO ₂ ratio is 1.0 or less, an AFX zeolite can be obtained with a higher yield. The OH / SiO ₂ ratio of the raw material composition is 0.1 or more, and further 0.5 or more. A particularly preferable OH / SiO ₂ ratio is 0.5 or more and 1.0 or less.

If the molar ratio of water (H ₂ O) to silica (hereinafter also referred to as “H ₂ O / SiO ₂ ratio”) is 50 or less, and further 30 or less, the H ₂ O / SiO ₂ ratio exceeds 50. Compared with the case, AFX type zeolite can be obtained more efficiently. In order to obtain a raw material composition having appropriate fluidity, the H ₂ O / SiO ₂ ratio may be 3 or more, and further 5 or more.

Particularly preferable raw material compositions include the following.
SiO ₂ / Al ₂ O ₃ ratio = 10 or more, 50 or less Alkali / SiO ₂ ratio = 0.1 or more, 1 or less P-SDA / SiO ₂ ratio = 0.01 or more, 0.5 or less N-SDA / SiO ₂ Ratio = 0.001 or more, 0.5 or less N-SDA / SDA ratio == 0.01 or more, 0.9 or less OH / SiO ₂ ratio = 0.1 or more, 1.0 or less H ₂ O / SiO ₂ ratio = 3 to 50

  In addition, when the raw material composition contains a compound containing fluorine, the production cost tends to increase. Therefore, it is preferable that the raw material composition does not substantially contain fluorine (F). The composition of the raw material composition of the present invention can be measured by the ICP method.

  In the crystallization step, the raw material composition containing each of the above raw materials is hydrothermally synthesized to be crystallized. The crystallization treatment may be performed by filling the raw material composition in a sealed container and heating it.

  If the crystallization temperature is 80 ° C. or higher, the raw material composition can be crystallized. Higher temperatures promote crystallization. Therefore, the crystallization temperature is preferably 100 ° C. or higher, more preferably 120 ° C. or higher. If the raw material composition is crystallized, it is not necessary to raise the crystallization temperature more than necessary. Therefore, the crystallization temperature may be 200 ° C. or lower, further 180 ° C. or lower, and further 160 ° C. or lower. In addition, crystallization can be performed in any state of stirring the raw material composition and standing.

  The production method of the present invention may include at least one of a washing step, a drying step, and an ion exchange step (hereinafter also referred to as “post-treatment step”) after the crystallization step.

  In the washing step, the AFX zeolite after crystallization and the liquid phase may be subjected to solid-liquid separation by a known method, and the AFX zeolite obtained as a solid phase may be washed with pure water.

  In the drying step, moisture is removed from the AFX zeolite after the crystallization step or the washing step. Although the conditions for the drying step are arbitrary, it can be exemplified that the AFX zeolite after the crystallization step or the washing step is allowed to stand in the atmosphere at 50 ° C. or higher and 150 ° C. or lower for 2 hours or longer.

The AFX zeolite after crystallization may have metal ions such as alkali metal ions on its ion exchange site. In the ion exchange step, this is ion-exchanged to a non-metallic cation such as ammonium ion (NH ₄ ⁺ ) or proton (H ⁺ ). Examples of ion exchange to ammonium ions include mixing and stirring AFX-type zeolite in an ammonium chloride aqueous solution. In addition, ion exchange with protons may be performed by ion-exchanging AFX zeolite with ammonia and calcining it.

  Hereinafter, the present invention will be described with reference to examples. However, the present invention is not limited to these examples. “Ratio” is “molar ratio” unless otherwise specified.

(Identification of crystal structure)
A general X-ray diffractometer (device name: D8 Advance, manufactured by Bruker) was used, and XRD measurement of the sample was performed under the following conditions. Using the measured XRD pattern, the crystal structure of the sample was identified by the following identification method.
Radiation source: CuKα ray (λ = 1.5405mm)
Measurement range: 2θ = 5 ° -50 °

  The obtained XRD pattern, the XRD pattern described in Collection of simulated XRD powder patterns for zeolitics, Fifth revised edition (2007), and the IZA structure committee website http: // www. isa-structure. The structure of the sample was identified by comparison with any of the XRD patterns described in Zeolite Framework Types at org / databases /.

(Composition analysis)
A sample solution was prepared by dissolving the sample in an aqueous potassium hydroxide solution. The composition of the sample was analyzed by measuring the sample solution by inductively coupled plasma emission spectrometry (ICP-AES) using a general ICP device (device name: SPS7000, manufactured by Seiko).
From the measured values of Si, Al, and P obtained, the SiO ₂ / Al ₂ O ₃ ratio, P / Al ratio, and P / T ratio of the sample were determined.

Example 1
Pure water, sodium hydroxide, FAU-type zeolite (Y-type, cation type: proton type, SiO ₂ / Al ₂ O ₃ ratio = 32, aluminosilicate) and TEPOH aqueous solution were mixed with [Dab-4] ²⁺ (OH ⁻ ) ₂ This was added to an aqueous solution and mixed to obtain a raw material composition having the following composition.
SiO ₂ / Al ₂ O ₃ ratio = 32
Na / SiO ₂ ratio = 0.6
P-SDA (TEP) / SiO 2 ratio = 0.18
N-SDA (Dab-4) / SiO ₂ ratio = 0.01
N-SDA / SDA ratio = 0.05
OH / SiO ₂ ratio = 0.8
H ₂ O / SiO ₂ ratio = 25

The obtained raw material composition was filled in an airtight container, and the raw material composition was crystallized under conditions of 140 ° C. and 2 days with the container left still. The raw material composition after crystallization was separated into solid and liquid, washed with pure water, and dried at 70 ° C. to obtain the zeolite of this example. The zeolite is an AFX type zeolite composed of a single phase having an AFX structure, and the SiO ₂ / Al ₂ O ₃ ratio = 12.1, the P / Al ratio = 0.08, and the P / T ratio = 0. 011.

  Table 1 shows the main composition of the raw material composition and the evaluation results of the AFX zeolite of this example. Moreover, the XRD pattern of the AFX type zeolite of the present example is shown in FIG. 1, and the SEM photograph is shown in FIG. From FIG. 2, it was confirmed that the average crystal grain size of the AFX zeolite of this example was 10 μm or less.

Example 2
A zeolite of this example was obtained in the same manner as in Example 1 except that the raw material composition was changed to the following composition.
SiO ₂ / Al ₂ O ₃ ratio = 32
Na / SiO ₂ ratio = 0.6
P-SDA (TEP) / SiO ₂ ratio = 0.10
N-SDA (Dab-4) / SiO 2 ratio = 0.05
N-SDA / SDA ratio = 0.33
OH / SiO ₂ ratio = 0.8
H ₂ O / SiO ₂ ratio = 5

The zeolite was an AFX type zeolite composed of a single phase having an AFX structure. The composition was SiO ₂ / Al ₂ O ₃ ratio = 9.6, P / Al ratio = 0.01, and P / T ratio = 0.002.
Table 1 shows the main composition of the raw material composition and the evaluation results of the AFX zeolite of this example.

Comparative Example 1
As a synthesis of conventional AFX zeolite, a zeolite of this comparative example was obtained in the same manner as in Example 1 except that the raw material composition was changed to the following composition.
SiO ₂ / Al ₂ O ₃ ratio = 32
Na / SiO ₂ ratio = 0.6
P-SDA (TEP) / SiO ₂ ratio = 0
N-SDA (Dab-4) / SiO 2 ratio = 0.1
OH / SiO ₂ ratio = 0.8
H ₂ O / SiO ₂ ratio = 25

The zeolite was an AFX type zeolite composed of a single phase having an AFX structure. The composition was SiO ₂ / Al ₂ O ₃ ratio = 10.0, P / Al ratio = 0, and P / T ratio = 0.
Table 1 shows the main composition of the raw material composition and the evaluation results of the AFX zeolite of this comparative example.

  The AFX zeolite of the present invention is, for example, a catalyst for producing lower olefins from alcohols and ketones, cracking catalysts, dewaxing catalysts, isomerization catalysts, and nitrogen oxide reduction catalysts from exhaust gas, and as a base material for these catalysts. Can be used. Furthermore, it can be used as a nitrogen oxide reduction catalyst. Moreover, since it has excellent heat resistance, it can be used even under high temperature conditions.

Claims (10)

  AFX-type zeolite containing phosphorus.   2. The AFX zeolite according to claim 1, wherein the phosphorus is contained in the pores.   The AFX zeolite according to claim 1 or 2, wherein the molar ratio of silica to alumina is 9 or more and 20 or less.   4. The AFX zeolite according to claim 1, wherein a molar ratio of the phosphorus to the skeleton metal is 0.001 or more and 0.1 or less.   A crystallization process of crystallizing a composition containing a silica source, an alumina source, a phosphonium cation source, and an ammonium cation source, The production of an AFX zeolite according to any one of claims 1 to 4 Method.   6. The production method according to claim 5, wherein the phosphonium cation source is at least one member selected from the group consisting of tetraethylphosphonium hydroxide, tetraethylphosphonium bromide, tetraethylphosphonium chloride, and tetraethylphosphonium iodide.   The ammonium cation source is 1,4-bis (1-azabicyclo [2.2.2] octane) butyl dioxide, 1,4-bis (1-azabicyclo [2.2.2] octane) butyl dichloride, , 4-bis (1-azabicyclo [2.2.2] octane) butyl dibromide, and 1,4-bis (1-azabicyclo [2.2.2] octane) butyl diiodide The manufacturing method according to claim 5 or 6, wherein:   The manufacturing method according to any one of claims 5 to 7, wherein a molar ratio of the ammonium cation to the total of the phosphonium cation and the ammonium cation is 0.01 or more and less than 1.0.   The method according to any one of claims 5 to 8, wherein the silica source and the alumina source are crystalline aluminosilicates.   The method according to any one of claims 5 to 9, wherein the silica source and the alumina source are FAU type zeolite.