JP2016104690A - Aei type zeolite, manufacturing method therefor and manufacturing method of lower olefin using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fine particle crystal AEI type zeolite capable of becoming a catalyst exhibiting high activity and high selectivity, and catalyst performance excellent in catalyst life when used as a catalyst for manufacturing lower olefin from an organic compound raw material and a manufacturing method therefor.SOLUTION: There is provided AEI zeolite containing silicon and at least one kind of hetero metal element selected from aluminum, gallium, boron and iron and having a structure of AEI by cord defined by International Zeolite Association (IZA) and average particle diameter of less than 400 nm. There is provided AEI zeolite containing at least aluminum as the hetero metal element.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a microcrystalline AEI zeolite having an average particle diameter of less than 400 nm, a method for producing the same, and a method for producing a lower olefin using the same.

  The AEI zeolite is one of synthetic zeolites having oxygen 8-membered ring pores, and is classified as AEI according to the structure code defined by International Zeolite Association (hereinafter sometimes abbreviated as “IZA”). Topology. SSZ-39, which is an aluminosilicate, has been reported as a zeolite having an AEI type structure (Patent Document 1).

Zeolites are used in various applications such as catalysts, adsorbents, and separators. Among these, AEI zeolite (Patent Document 1) has a small pore size and a high acid strength, and is expected as a catalyst for olefin production and a catalyst for automobile exhaust gas treatment.
In Patent Document 1, it is derived from N, N-dialkylpiperidine such as N, N-dimethyl-3,5-dimethylpiperidinium cation (hereinafter sometimes referred to as “DMDMP”) as a structure directing agent. A quaternary ammonium cation (hereinafter sometimes referred to as “DAP”) or the like is used under alkaline conditions (alkali metal / Si molar ratio of about 0.48-0.
58) discloses a method for hydrothermal synthesis. In the examples, there is no description regarding the particle size, but when the examples were further tested, the particle size was about 0.8-1.5 μm. In Patent Document 2, an N, N-diethyl-2,6-dimethylpiperidinium cation (hereinafter sometimes referred to as “DEDMP”) is used as a structure directing agent, and a high DEDMP / Si molar ratio (Examples) 0.5), and an AEI zeolite having a high silica composition produced by adding hydrogen fluoride is disclosed. In the examples, it is reported as thick plate-like particles having a particle size of 2.5 × 2.5 × 1.5 μm.

  Non-Patent Document 1 proposes a hydrothermal synthesis method using a tetraethylphosphonium cation as a structure-directing agent. Among them, AEI zeolite having a shape close to a cubic crystal having a particle diameter of 400 to 600 nm has been reported.

US Pat. No. 5,958,370 US Patent No. 70008610

Chem. Lett. 43, (2014) 302

  However, since the conventional AEI zeolite has a large crystal particle size, it is disadvantageous in terms of diffusibility in the crystal and catalyst effectiveness factor in various catalytic reactions. For example, in a reaction for producing a lower olefin by a conversion reaction of an organic compound, a zeolite having a large particle size has low diffusibility in the crystal, so that coking is likely to proceed, and a sufficient lower olefin yield is difficult to obtain. There was a problem.

  The present invention has been made in view of the above problems, and can be a catalyst exhibiting high activity, high selectivity, and excellent performance in catalyst life when used as a catalyst for the production of lower olefins from organic compound raw materials. It is an object of the present invention to provide a microcrystalline AEI zeolite and a method for producing the same.

  As a result of intensive studies to solve the above problems, the present inventors have found that a silica source, a heterometallic element source containing at least one selected from the group consisting of aluminum, gallium, boron, and iron, and an alkali metal In the method for producing AEI zeolite by hydrothermal synthesis reaction of a mixture containing an element source and / or an alkaline earth metal element source, a quaternary ammonium salt and water, any one of the following (1) to (4) The inventors have found that an AEI zeolite having an average particle diameter of less than 400 nm can be produced by the method, and have reached the present invention.

(1) A method of pre-heating before adding a quaternary ammonium salt (2) A method of pre-heating the mixture at a temperature 10 ° C. or more lower than the hydrothermal synthesis temperature (3) An organic structure-directing agent in the mixture And / or a method of adding a seed crystal composed of zeolite having an average particle size of less than 500 nm (4) Aluminum hydroxide is used as a heterometallic element source, and no organic structure directing agent is included or / and the average particle size is A method for adding seed crystals composed of zeolite of less than 500 nm, ie, the gist of the present invention is as follows.

[1] A zeolite containing silicon and at least one heterometallic element selected from the group consisting of aluminum, gallium, boron, and iron, the structure of which is defined by the International Zeolite Association (IZA) as a code defined by AEI An AEI zeolite having an average particle diameter of less than 400 nm.
[2] The AEI zeolite according to [1], wherein the heterometallic element contains at least aluminum.
[3] The AEI zeolite according to [1] or [2], wherein the average particle size is less than 300 nm.
[4] A mixture containing a silica source, a heterometallic element source containing at least one selected from the group consisting of aluminum, gallium, boron, and iron, an alkali metal element source and / or an alkaline earth metal element source, and water [1] to [3], characterized by having a pretreatment step of heating the mixture, and a hydrothermal synthesis step of adding a quaternary ammonium salt to the mixture obtained by the pretreatment step to cause a hydrothermal synthesis reaction. ] The manufacturing method of the AEI zeolite in any one of.
[5] A silica source, a heterometallic element source containing at least one selected from the group consisting of aluminum, gallium, boron, and iron, an alkali metal element source and / or an alkaline earth metal element source, and quaternary ammonium A pretreatment step of heating a mixture containing salt and water, and a hydrothermal synthesis step of hydrothermal synthesis reaction of the mixture obtained by the pretreatment step, wherein the temperature of the pretreatment step is the temperature of the hydrothermal synthesis step The method for producing an AEI zeolite according to any one of [1] to [3], which is lower by 10 ° C. or more.
[6] A silica source, a heterometallic element source containing at least one selected from the group consisting of aluminum, gallium, boron, and iron, an alkali metal element source and / or an alkaline earth metal element source, and quaternary ammonium To the mixture containing salt and water, 0.1% by mass or more of seed crystals made of zeolite not containing an organic structure-directing agent or / and having an average particle diameter of less than 500 nm are added relative to the weight of silica in the mixture. The method for producing an AEI zeolite according to any one of [1] to [3], comprising a step of performing a thermal synthesis reaction.
[7] The method for producing an AEI zeolite according to any one of [4] to [6], wherein the heterometallic element source includes FAU-type zeolite containing aluminum.
[8] Does not contain silica source, aluminum hydroxide, alkali metal element source and / or alkaline earth metal element source, quaternary ammonium salt, organic structure directing agent or / and average particle size is 50
The method for producing an AEI zeolite according to any one of [1] to [3], comprising a step of hydrothermal synthesis reaction of a mixture containing seed crystals of zeolite less than 0 nm and water.
[9] The method for producing an AEI zeolite according to [6] or [8], wherein the seed crystal is a zeolite having a 6-membered ring and / or an 8-membered ring as a secondary building unit.
[10] The hetero metal element source includes a FAU-type zeolite containing aluminum, and the seed crystal is a zeolite having a 6-membered ring and / or an 8-membered ring as a secondary building unit. A method for producing the AEI zeolite according to 1.
[11] A method for producing a lower olefin by bringing an organic compound raw material into contact with the AEI zeolite according to any one of [1] to [3].
[12] The method for producing a lower olefin according to [11], wherein the organic compound raw material is ethylene, and the lower olefin is propylene and linear butene.

  The microcrystalline AEI zeolite having an average particle diameter of less than 400 nm according to the present invention can be used for catalytic reactions such as a lower olefin production reaction from an organic compound raw material, has low coking deterioration, high activity and high selectivity, and Catalyst performance with excellent catalyst life can be realized.

It is an XRD chart of the AEI zeolite manufactured in Example 1 of this invention. It is a SEM photograph of AEI type zeolite manufactured in Example 1 of the present invention. It is an XRD chart of the AEI zeolite manufactured in Example 2 of the present invention. It is a SEM photograph of AEI type zeolite manufactured in Example 2 of the present invention. It is an XRD chart of the AEI zeolite manufactured in Example 3 of the present invention. It is a SEM photograph of the AEI zeolite manufactured in Example 3 of the present invention. It is an XRD chart of the product of the comparative example 1 of this invention. It is an XRD chart of the product of the comparative example 2 of this invention. It is an XRD chart of the product of the comparative example 3 of this invention. It is an XRD chart of the product of Example 4 of this invention. It is a scanning electron micrograph of the product of Example 4 of the present invention. It is an XRD chart of the product of Example 5 of this invention. It is a scanning electron micrograph of the product of Example 5 of this invention.

  Hereinafter, typical embodiments for carrying out the present invention will be specifically described. However, the present invention is not limited to the following embodiments as long as the gist of the present invention is not exceeded, and various modifications may be made. Can do.

1. AEI-type zeolite The AEI-type zeolite in the present invention is a zeolite containing silicon and at least one heterometallic element selected from the group consisting of aluminum, gallium, boron, and iron, and has a structure of International Zeolite Association (IZA). ) In the code specified by
EI and the average particle size is less than 400 nm.

The zeolite in the present invention usually has crystallinity. The zeolite contains at least one heterometallic atom M other than silicon and oxygen in its structure. Zeolite is a porous crystalline compound that usually forms open regular micropores (hereinafter sometimes simply referred to as “pores”), and has a tetrahedral structure of TO ₄ units (T Means an atom other than oxygen constituting the zeolite, hereinafter referred to as T atom), and has a structure in which the oxygen atom is shared and three-dimensionally connected.

The AEI type in the present name refers to a structure having an AEI code defined by the International Zeolite Association (IZA).
The AEI zeolite has three-dimensional pores composed of three types of 3.8 × 3.8Å 8-membered ring pores. When the eight-membered ring pores intersect, a wide cavity (cage) exists in the structure. In addition, when the unit cell (unit cell) of the AEI type structure is expressed by an atom having a fixed spatial coordinate, its composition is T ₄₈ O _{96 and} it is a monoclinic system.

The framework density of AEI zeolite is usually 14.8 T / nm ³ .
The framework density (unit: T / nm ³ ) means the number of atoms (T atoms) other than oxygen that form a skeleton existing per unit volume (1 nm ³ ) of the zeolite. It depends on the structure. The relationship between the framework density and the structure of the zeolite is shown in the data collection on zeolite (Atlas of Zeolite Framework Types, Sixth Revised Edition 2007, ELSEVIER) compiled by the IZA Structure Commission. .

  The average particle size of the AEI zeolite of the present invention is less than 400 nm, preferably less than 300 nm, more preferably less than 200 nm, usually 10 nm or more, preferably 20 nm or more, more preferably 30 nm or more. It is. By being less than the above upper limit, the diffusivity in the zeolite crystals and the catalyst effectiveness coefficient in the catalytic reaction are sufficiently high, and by being above the above lower limit, the zeolite crystallinity becomes sufficient and the hydrothermal stability is high. Is preferable.

In addition, the average particle diameter in this invention is corresponded to the particle diameter of a primary particle. Therefore, it is different from the particle diameter of the aggregate measured by the light scattering method or the like. The average particle diameter is measured by arbitrarily measuring 10 or more particles in the observation of particles with a scanning electron microscope (hereinafter abbreviated as “SEM”) or a transmission electron microscope (hereinafter abbreviated as “TEM”). The average particle diameter of the primary particles is obtained. If the particle is a rectangle, measure the long and short sides of the particle (not measuring the depth) and calculate the average of the sum (ie (long side + short side) ÷ 2) The diameter.

2. Production Method of AEI Type Zeolite The production method of the AEI type zeolite of the present invention specifically includes the following four production methods.
A first aspect of the present invention (hereinafter referred to as “first invention”) includes a silica source and a heterometallic element source containing at least one selected from the group consisting of aluminum, gallium, boron, and iron, A pretreatment step of heating a mixture containing an alkali metal element source and / or an alkaline earth metal element source and water, and a quaternary ammonium salt is added to the mixture obtained by the pretreatment step to cause a hydrothermal synthesis reaction. A method for producing an AEI zeolite, comprising a hydrothermal synthesis step.

  A second aspect of the present invention (hereinafter referred to as “second invention”) includes a silica source and a heterometallic element source containing at least one selected from the group consisting of aluminum, gallium, boron, and iron, A pretreatment step of heating a mixture containing an alkali metal element source and / or an alkaline earth metal element source, a quaternary ammonium salt and water, and hydrothermal synthesis in which the mixture obtained by the pretreatment step is subjected to a hydrothermal synthesis reaction A method for producing an AEI zeolite comprising a step, wherein the temperature of the pretreatment step is 10 ° C. or more lower than the temperature of the hydrothermal synthesis step.

  A third aspect of the present invention (hereinafter referred to as “third invention”) includes a silica source and a heterometallic element source containing at least one selected from the group consisting of aluminum, gallium, boron, and iron, In a mixture containing an alkali metal element source and / or an alkaline earth metal element source, a quaternary ammonium salt and water, a seed crystal composed of a zeolite not containing an organic structure directing agent or / and having an average particle diameter of less than 500 nm A method for producing an AEI zeolite comprising a step of adding 0.1% by mass or more to a weight of silica in a mixture to cause a hydrothermal synthesis reaction.

  A fourth aspect of the present invention (hereinafter referred to as “fourth invention”) includes a silica source, aluminum hydroxide, an alkali metal element source and / or an alkaline earth metal element source, a quaternary ammonium salt, and an organic structure definition. A method for producing an AEI zeolite, comprising a step of hydrothermal synthesis reaction of a mixture containing seed crystals not containing an agent and / or zeolite having an average particle diameter of less than 500 nm and water.

Hereinafter, the first to fourth inventions (hereinafter, these inventions may be collectively referred to as “the present invention”) will be described in detail.
In the method for producing an AEI zeolite of the present invention, an AEI zeolite can be produced according to a conventional method for hydrothermal synthesis of zeolite, except for the above characteristics. That is, a mixture of a crystal precursor containing a silica source, a hetero metal element source, an alkali metal element source and / or an alkaline earth metal element source, and a quaternary ammonium salt, if necessary, a seed crystal is prepared. It can be synthesized by hydrothermal synthesis.
The hydrothermal synthesis common to the first to fourth inventions will be described below.

[Hydrothermal synthesis]
(Silica source)
The silica source used in the present invention is not particularly limited, and examples thereof include finely divided silica, silica sol, silica gel, silicon dioxide, water glass and other silicates, silicon alkoxides such as tetramethoxysilane and tetraethoxysilane, and silicon halides. Further, silica-containing zeolite such as FAU type zeolite or CHA type zeolite may be used as the silica source.

These silica sources may be used alone or in combination of two or more.
Of these silica raw materials, fine silica, silica sol, water glass, silica-containing zeolite and the like are preferably used in terms of cost advantage and ease of handling, and more preferably in terms of reactivity. Water glass and silica-containing zeolite are used.
(Heterometallic element source including at least one selected from the group consisting of aluminum, gallium, boron, and iron)

  The AEI zeolite in the present invention includes at least one heterometallic element selected from aluminum, gallium, boron, and iron in addition to silicon, oxygen, an alkali metal element, and an alkaline earth metal element as constituent elements of the zeolite (hereinafter referred to as “the zeolite element”). , Simply referred to as “heterometallic element”). In addition to the hetero metal element, other elements may be contained, and the other elements are not particularly limited, and examples thereof include zinc, germanium, titanium, zirconium, tin, chromium, and cobalt. These may contain only 1 type in the mixture, and may contain 2 or more types.

Preferred heterometallic elements for the present invention are aluminum, gallium and boron, more preferably aluminum. This is because if aluminum is present in the mixture during hydrothermal synthesis, the AEI type is easily oriented.
The hetero metal element source is not particularly limited, and is selected from, for example, sulfates, nitrates, hydroxides, oxides, and alkoxides of these hetero metal elements.

Of these heterometallic element sources, sulfates, nitrates, hydroxides, and alkoxides are preferable in terms of reactivity, and sulfates, nitrates, and hydroxides are more preferable in terms of costs and work.
As the aluminum source, aluminum alkoxide such as aluminum sulfate, aluminum nitrate, aluminum hydroxide, sodium aluminate, pseudoboehmite, alumina sol, aluminum isopropoxide and the like are usually used. Moreover, you may use aluminum containing zeolites, such as a FAU type zeolite and a CHA type zeolite, as an aluminum source.

Of these aluminum sources, aluminum sulfate, aluminum nitrate, aluminum hydroxide, and aluminum-containing zeolite are preferable in terms of reactivity, and aluminum hydroxide and aluminum-containing zeolite are more preferable.
Further, as the gallium source, usually gallium sulfate, gallium nitrate, gallium oxide, gallium chloride, gallium phosphate, gallium hydroxide, gallium-containing zeolite, etc. are used, preferably gallium sulfate, gallium nitrate, more preferably Gallium nitrate.

As the boron source, boric acid, sodium borate, boron oxide, boron-containing zeolite and the like are usually used, preferably boric acid and sodium borate, and more preferably boric acid.
As the iron source, iron nitrate, iron sulfate, iron oxide, iron chloride, iron hydroxide, iron-containing zeolite and the like are usually used, preferably iron sulfate and iron nitrate, and more preferably iron nitrate.
These heterometallic element sources may be used alone or in combination of two or more of the same heterometallic elements, or one or more of the different heterometallic elements may be used. You may use it in combination.

(Alkali metal element source and / or alkaline earth metal element source)
The alkali metal element and alkaline earth metal element contained in the mixture to be subjected to the hydrothermal synthesis of the present invention are not particularly limited, and include lithium, sodium, potassium, calcium, etc., and these are included alone. 2 or more types may be contained, but it is preferable that the alkali metal element is included in terms of high alkalinity and in particular, when a solid silica raw material is used, crystallization of zeolite is likely to occur.

Examples of the alkali metal element source and alkaline earth metal element source include hydroxides, chlorides, bromides, iodides, hydrogen carbonates, carbonates, and the like. Of these compounds, hydroxides, bicarbonates and carbonates are basic in an aqueous solution state. Specific examples include sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium hydrogen carbonate, potassium hydrogen carbonate, sodium carbonate, potassium carbonate, calcium carbonate, etc. Among these, sodium hydroxide, potassium hydroxide, etc. These alkali metal hydroxides are preferred because they have a high alkalinity, and particularly have the effect of promoting dissolution of the silica raw material and subsequent crystallization of the zeolite when a solid silica raw material is used.
These alkali metal element sources and alkaline earth metal element sources may be used alone or in combination of two or more.

(Quaternary ammonium salt)
Quaternary ammonium salts used as structure directing agents include cations derived from N, N-dialkylpiperidine, cations derived from N, N-dialkyl-9-azoniabicyclo [3.3.1] nonane, And cations derived from azoniabicyclo [3.2.1] octane, cations derived from N, N-dialkyl-2,5-dihydropyrrole, and the like. Among them, a cation derived from N, N-dialkylpiperidine is preferable.

  The two independent alkyl groups of N, N-dialkylpiperidine, N, N-dialkyl-9-azoniabicyclo [3.3.1] nonane and N, N-dialkyl-2,5-dihydropyrrole are of the AEI type structure. There are no particular limitations as long as it is a structure-directing agent that contributes to formation, and it is usually a lower alkyl group, preferably an alkyl group having 4 or less carbon atoms, more preferably a methyl group or an ethyl group. The alkyl group may be linear or two alkyl groups may form a ring.

The piperidine ring of the N, N-dialkylpiperidine may have a substituent, specifically, a lower alkyl group. When cis-trans isomers are present depending on the arrangement of substituents, any of these isomers may be used, or a mixture of isomers may be used.
Of the above, N, N-dimethyl-3,5-dimethylpiperidinium cation, N, N-diethyl-2,6-dimethylpiperidinium cation, N, N-dimethyl-9-azoniabicyclo [3. 3.1] Nonane cation, more preferably N, N-dimethyl-3,5-dimethylpiperidinium cation.

The quaternary ammonium cation used as the structure directing agent is accompanied by an anion that does not inhibit the formation of the AEI zeolite of the present invention. The anion is not particularly limited, and specific examples include halogen ions such as Cl ⁻ , Br ⁻ and I ⁻ , hydroxide ions, acetates, sulfates and carboxylates. Among these, hydroxide ions are particularly preferably used.
Quaternary ammonium salts may be used alone or in combination of two or more.

(Seed crystal)
In the present invention, seed crystals may be added to the mixture used for hydrothermal synthesis. This seed crystal is preferably a zeolite having a 6-membered ring and / or an 8-membered ring as a secondary building unit, more preferably AEI type, AFX type, CHA type, ERI type, FAU type, LEV type, AEI type, CHA. More preferred are molds and FAU types.
Only one type of seed crystal may be used, or a combination of different structures and compositions may be used. The composition of the zeolite used as the seed crystal is not particularly limited as long as it does not greatly affect the composition of the mixture.

The particle size of the zeolite used as a seed crystal is desirably smaller for efficient crystallization, and the primary particle size is usually 10 nm or more, preferably 30 nm or more, and the upper limit is usually 5 μm or less, preferably 3 μm. It is as follows.
The seed crystal may be either zeolite containing a structure directing agent or zeolite not containing it.
The seed crystal may be added to the mixture after being dispersed in an appropriate solvent such as water, or may be added directly without being dispersed.

(Composition of the mixture)
In the present invention, the preferred composition of the mixture (slurry or gel) subjected to hydrothermal synthesis is as follows.
The ratio of the heterometallic element in the mixture is not particularly limited, but when the heterometallic element other than silicon and oxygen is represented by M, it is usually 5 or more when represented by the SiO ₂ / M ₂ O ₃ molar ratio. , Preferably 8 or more, more preferably 10 or more, usually 500 or less, preferably 300 or less, more preferably 100 or less. Note the ratios, all Si atoms in the zeolite contains as SiO _2, is a value determined on the assumption that the M contained in the zeolite is included as all M ₂ O _3. When the SiO ₂ / M ₂ O ₃ molar ratio is in the above range, a sufficient amount of acid can be obtained and high catalytic activity can be obtained. In addition, it is possible to prevent phenomena such as deactivation of the catalyst due to adhesion of coke, elimination of T atoms other than silicon from the skeleton, and a decrease in acid strength per acid point.

The total molar ratio [(alkali metal element + alkaline earth metal element) / SiO ₂ (molar ratio)] of alkali metal and alkaline earth metal to silica in the mixture is not particularly limited, but is usually 0. .6 or less, preferably 0.45 or less, more preferably 0.35 or less, particularly preferably 0.30 or less, usually 0.01 or more, preferably 0.03 or more, more preferably 0.04 or more. is there. Alkali metal elements and alkaline earth metal elements are incorporated into AEI zeolite as counter cations of hetero metal elements, and crystallization proceeds. If the molar ratio is too large, the incorporation rate of the heterometallic element into the zeolite skeleton increases, and the silica component that remains without being consumed as a raw material increases, so that the SiO ₂ / M ₂ O ₃ molar ratio of the product is increased. The synthesis yield of AEI zeolite is lowered. On the other hand, if the molar ratio is too small, the crystallization rate of the AEI zeolite is not sufficient, and synthesis may take a long time, or a zeolite having a structure different from that of the AEI type may be generated. Note that the calculation of the molar ratio does not include silica, alkali metal, and alkaline earth metal in the seed crystal.

  The ratio of the quaternary ammonium salt used as the structure directing agent in the mixture is not particularly limited, but the molar ratio of the quaternary ammonium salt to the Si element (quaternary ammonium salt / Si) is usually 0.005 or more. The upper limit is usually 0.7 or less, preferably 0.6 or less, more preferably 0.5 or less.

If this value is too small, crystallization of AEI zeolite will not proceed easily, and if it is too large, the cost for producing the zeolite will increase.
The ratio of water in the mixture is not particularly limited, but the molar ratio of H ₂ O to Si element (H ₂ O / Si molar ratio) is usually 3 or more, preferably 5 or more, more preferably 10 The upper limit is usually 100 or less, preferably 50 or less, more preferably 30 or less.

When the proportion of water is too small, the viscosity of the mixture increases, and stirring and mixing during the production of the mixture or during crystallization by hydrothermal synthesis tends to be difficult. On the other hand, if the ratio of water is too high, the crystallization rate is lowered, the amount of zeolite produced per mixture is further reduced, and the productivity is lowered.
The amount of seed crystals added to the mixture is not particularly limited, and is usually 0.1% by mass or more, preferably 0.5% by mass or more, more preferably 1% by mass or more, and the upper limit is usually 30% by mass. Hereinafter, it is preferably 20% by mass or less.

  If the amount of the seed crystal is too small, the number of precursors directed to the AEI type structure is reduced, so that it becomes difficult to obtain an AEI type zeolite. When there are too many seed crystals, the ratio of the seed crystals contained in the product increases, so that newly produced AEI zeolite tends to decrease from the mixture, resulting in low productivity.

(Hydrothermal synthesis process)
By heating the above mixture in a reaction vessel (hydrothermal synthesis), AEI zeolite can be produced.
The heating temperature (reaction temperature) is not particularly limited, and is usually 100 ° C. or higher, preferably 120 ° C. or higher, more preferably 140 ° C. or higher, and the upper limit is usually 220 ° C. or lower, preferably 20
0 ° C or lower, more preferably 190 ° C or lower.

If the reaction temperature is too low, the crystallization time of the AEI zeolite tends to be long, and if the reaction temperature is too high, a zeolite having a structure different from that of the AEI type may be generated.
The time required to raise the temperature to the heating temperature (reaction temperature) is not particularly limited, and is usually 0.1 hour or longer, preferably 0.5 hour or longer, more preferably 1 hour or longer. There is no particular upper limit for the time required for.

The heating time (reaction time) is usually 1 hour or longer, preferably 5 hours or longer, more preferably 10 hours or longer, and the upper limit is usually 14 days or shorter, preferably 7 days or shorter, more preferably 3 days or shorter. is there.
If the reaction time is too short, crystallization of the AEI zeolite may be insufficient, and if the reaction time is too long, a zeolite having a structure different from that of the AEI type may be generated.
The pressure during the reaction is not particularly limited, and the self-generated pressure generated when the mixture placed in the sealed container is heated to the above temperature range is sufficient, but if necessary, an inert gas such as nitrogen may be added. Good.
The characteristics of the production method of the present invention are described below.

[First invention]
In the first invention, a silica source, a hetero metal element source containing at least one selected from the group consisting of aluminum, gallium, boron, and iron, an alkali metal element source and / or an alkaline earth metal element source, and water And a hydrothermal synthesis step of adding a quaternary ammonium salt to the mixture obtained by the pretreatment step to cause a hydrothermal synthesis reaction.

Before adding the quaternary ammonium salt that acts as a structure-directing agent, the mixture is preheated to promote the formation of unit units of the zeolite, and in the hydrothermal synthesis reaction after addition of the quaternary ammonium salt, Generation of AEI zeolite with fine crystal can be produced.
The temperature of the pretreatment step is not particularly limited, but is usually 60 ° C. or higher, preferably 80 ° C. or higher, more preferably 100 ° C. or higher, and the upper limit is usually 200 ° C. or lower, preferably 190 ° C. Below, more preferably 180 ° C. or less.

The treatment time of the pretreatment step is not particularly limited, but is usually 7 days or less, preferably 3 days or less, more preferably 1 day or less, and there is no particular lower limit. The treatment time of the pretreatment step is preferably shorter than the synthesis time of the hydrothermal synthesis step from the viewpoint of productivity, and the treatment time can be changed according to the temperature of the pretreatment step.
In addition, when adding a quaternary ammonium salt to the mixture obtained by the pretreatment step, a silica source, an alkali metal element source / alkaline earth metal element source, a hetero metal element source, and water are additionally added at an arbitrary ratio. May be.

[Second invention]
In the second invention, a silica source, a hetero metal element source containing at least one selected from the group consisting of aluminum, gallium, boron and iron, an alkali metal element source and / or an alkaline earth metal element source, A pretreatment step of heating a mixture containing a quaternary ammonium salt and water, and a hydrothermal synthesis step of hydrothermal synthesis reaction of the mixture obtained by the pretreatment step, wherein the temperature of the pretreatment step is the hydrothermal synthesis step A pretreatment step of treating at a temperature lower by 10 ° C. or more than the above temperature.

By pretreating the mixture at a temperature lower by 10 ° C. or more than the temperature of the hydrothermal synthesis step, it is possible to promote the generation of crystal nuclei while suppressing crystal growth, and therefore to produce AEI zeolite with fine crystal crystals Can do.
The temperature of the pretreatment step is 10 ° C. or more lower than the temperature of the hydrothermal synthesis step, preferably 20 ° C. or lower, more preferably 30 ° C. or lower, usually 40 ° C. or higher, preferably 60 ° C. or higher, more preferably It is 80 ° C or higher. By setting the temperature of the pretreatment step within the above range, crystal growth in the pretreatment step can be suppressed, and generation of crystal nuclei can be made sufficient.

The treatment time of the pretreatment step is not particularly limited, but is usually 7 days or less, preferably 4 days or less, more preferably 2 days or less, and there is no particular lower limit. The treatment time of the pretreatment step is preferably shorter than the synthesis time of the hydrothermal synthesis step from the viewpoint of productivity, and the treatment time can be changed depending on the temperature of the pretreatment step.
In addition, a silica source, a hetero metal element source, an alkali metal element source / alkaline earth metal element source, a quaternary ammonium salt, and water may be additionally added to the mixture obtained by the pretreatment step in an arbitrary ratio. .

[Third invention]
In the third invention, a silica source, a hetero metal element source containing at least one selected from the group consisting of aluminum, gallium, boron, and iron, an alkali metal element source and / or an alkaline earth metal element source, To a mixture containing a quaternary ammonium salt and water, 0.1% by mass or more of a seed crystal not containing an organic structure-directing agent or / and comprising zeolite having an average particle diameter of less than 500 nm is added based on the weight of silica in the mixture. And a hydrothermal synthesis reaction step.

By using a seed crystal that does not contain an organic structure directing agent or / and that has a mean particle diameter of less than 500 nm, it is possible to promote the dissolution of seed crystals and the generation of crystal nuclei in the mixture. Type zeolite can be produced.
Zeolite that does not contain an organic structure-directing agent is one that has been subjected to a treatment that removes the organic compound used as the structure-directing agent (for example, baking treatment or solvent extraction), or uses an organic compound as a structure-directing agent Any of those synthesized without. Here, “not containing an organic structure-directing agent” means that the content of organic substances derived from the structure-directing agent contained is less than 1% by mass.

The method for measuring the organic substance content derived from the organic structure directing agent is not particularly limited. For example, thermogravimetric analysis (TG) is performed in an atmosphere containing oxygen, and the organic substance content is obtained from the weight reduction. be able to.
Moreover, if it does not contain an organic structure directing agent, zeolites in various states can be used. For example, as the counter cation of the hetero metal atom, any of alkali metal type zeolite containing an alkali metal cation such as sodium, NH ₄ type zeolite containing an ammonium cation, and H type zeolite containing a proton may be used.

When a zeolite containing no organic structure directing agent is used as a seed crystal, the average particle size of the zeolite is not particularly limited, but is usually less than 2 μm, preferably less than 1 μm, more preferably less than 500 nm, The lower limit is usually 10 nm or more, preferably 20 nm or more, more preferably 30 nm or more.
When a zeolite having an average particle diameter of less than 500 nm is used as a seed crystal, any of those containing or not containing an organic structure directing agent may be used. The average particle diameter of the zeolite is less than 500 nm, preferably less than 300 nm, more preferably less than 200 nm, and the lower limit is usually 10 nm or more, preferably 20 nm or more, more preferably 30 nm or more. The smaller the particle size, the higher the dissolution rate and the higher the concentration of crystal nuclei in the mixture.

The addition amount of the seed crystal is 0.1% by mass or more, preferably 0.5% by mass or more, more preferably 1% by mass or more, and the upper limit is usually 30% by mass or less based on the weight of silica. , Preferably 25% by mass or less, more preferably 20% by mass or less.
In said 1st invention-3rd invention, it is preferable that a heterometallic element source contains the FAU type zeolite containing aluminum.

FAU type zeolite has a 6-membered ring as a secondary building unit in common with AEI type zeolite and d6r as a composite building unit, so that AEI type crystal growth is easy to proceed and is an inexpensive raw material. Therefore, it is preferable. The FAU-type zeolite is not particularly limited as long as it is FAU-type, but usually a Y-type zeolite having a SiO ₂ / Al ₂ O ₃ molar ratio of 3 or more is used, and SiO in the mixture used for the hydrothermal synthesis reaction is used. Depending on the ₂ / Al ₂ O ₃ molar ratio, the SiO ₂ / Al ₂ O ₃ molar ratio and the amount added of the Y-type zeolite to be used can be appropriately adjusted.

[Fourth Invention]
In the fourth invention, the silica source, the alkali metal element source and / or the alkaline earth metal element source, the quaternary ammonium salt, the aluminum hydroxide, the organic structure directing agent is not included, and / or the zeolite has an average particle diameter of less than 500 nm. And a hydrothermal synthesis reaction of the seed crystal and the mixture containing water.

By using aluminum hydroxide having relatively low solubility as the Al source and not containing an organic structure-directing agent that easily generates crystal nuclei and / or using zeolite having an average particle diameter of less than 500 nm as seed crystals, Since the generation of crystal nuclei is more advantageous than the crystal growth in A, the fine crystal AEI zeolite can be produced.
Seed crystals made of zeolite containing no organic structure directing agent and seed crystals made of zeolite having an average particle size of less than 500 nm are synonymous with the third invention.

In 3rd invention and 4th invention, it is preferable that a seed crystal is a zeolite which has a 6-membered ring and / or an 8-membered ring as Secondary Building Unit.
By having a 6-membered ring and / or 8-membered ring as a secondary building unit,
AEI type nucleation is likely to occur and crystallization is likely to proceed.
Among the first to fourth inventions, in the third invention, the heterometallic element source includes a FAU-type zeolite containing aluminum, and the seed crystal has a 6-membered ring and / or an 8-membered ring as a secondary building unit. Is most preferred.

(Separation and purification process)
After the AEI zeolite obtained by hydrothermal synthesis is washed with water, it is desirable to remove the structure-directing agent contained in the zeolite.
The method for removing the structure-directing agent is not particularly limited, and may be carried out by a conventionally known method such as baking or solvent extraction, but baking is desirable.

The firing temperature is usually 350 ° C. or higher, preferably 400 ° C. or higher, more preferably 450 ° C., and the upper limit is usually 900 ° C. or lower, preferably 850 ° C. or lower, more preferably 800 ° C. or lower.
If the calcination temperature is too low, the residual ratio of the structure-directing agent tends to increase, and the pore volume of the zeolite decreases. On the other hand, if the calcination temperature is too high, the zeolite skeleton may be collapsed, the crystallinity may be lowered, or the crystal structure may not be maintained.

The firing time is not particularly limited as long as the structure-directing agent is sufficiently removed, but is preferably 1 hour or longer, more preferably 3 hours or longer, and the upper limit is usually 24 hours or shorter.
Firing is preferably performed in an atmosphere containing oxygen, and is usually performed in an air atmosphere.
The AEI zeolite prepared in this way may be subjected to a treatment such as reducing the amount of acid or modifying the composition by modifying the impregnation or loading of a metal element, if necessary. The acid amount reduction treatment can be performed, for example, by silylation, steam treatment, dicarboxylic acid treatment, or the like. These acid amount reduction treatment and composition change can be carried out by a commonly used method known per se.

3. Lower olefin production method The lower olefin production method of the present invention is characterized in that an organic compound raw material is brought into contact with the AEI zeolite produced by the above method to produce a lower olefin.
Here, the AEI zeolite is a catalytically active component in the conversion reaction from the organic compound raw material to the lower olefin.

(Treatment method of AEI zeolite)
The AEI zeolite used as the catalytically active component may be used after appropriately performing a treatment such as silylation treatment, steam treatment, heat treatment, acid treatment, or metal ion exchange. Among these, silylation treatment is preferably performed, and in addition to silylation treatment, at least one treatment selected from steam treatment, heat treatment, acid treatment, and metal ion exchange may be further performed. Hereinafter, these processing methods will be described.

(Silylation treatment)
A method of performing the AEI zeolite silylation treatment is not particularly limited, and a known method can be appropriately used. Specifically, liquid phase silylation, gas phase silylation, or the like can be performed.
It is considered that the AEI type zeolite is usually coated with the acid sites on the outer surface and inactivated by the silylation treatment, so that the acid amount on the outer surface decreases. When the outer surface acid amount is reduced, side reactions occurring on the outer surface of the zeolite are suppressed. Specifically, when the organic compound raw material or the lower olefin produced in the pores of the zeolite is in contact with the acid sites on the outer surface of the zeolite, there is an effect of suppressing the reaction that produces components other than the target product. Conceivable. In addition, in the silylation of the outer surface acid point, the silyl group is also bonded to the acid point that constitutes the pore of the zeolite, so the pore diameter of the outer surface opening is slightly reduced, and molecular diffusion to the outside of the crystal It is thought that there is also an effect of suppressing the above. This can suppress the generation of hydrocarbons having 5 or more carbon atoms, which are larger molecules, and improve the selectivity of lower olefins.

Hereinafter, the silylation treatment will be specifically described by taking liquid phase silylation as an example.
The silylating agent is not particularly limited, and a silylating agent is usually used that can silylate the outer surface of the zeolite and cannot silylate the pores of the zeolite. Specifically, silicones, chlorosilanes, alkoxysilanes, siloxanes, silazanes and the like can be used. Of these, chlorosilanes are usually used for gas phase silylation, and alkoxysilanes are usually used for liquid phase silylation, and more preferred silylating agents are highly reactive and relatively easy to handle. , Alkoxysilanes.

Specific silicones include dimethyl silicone, diethyl silicone, phenylmethyl silicone, methyl hydrogen silicone, ethyl hydrogen silicone, phenyl hydrogen silicone, methyl ethyl silicone, phenyl ethyl silicone, diphenyl silicone, methyl trifluoropropyl silicone. Ethyl trifluoropropyl silicone, tetrachlorophenyl methyl silicone, tetrachlorophenyl ethyl silicone, tetrachlorophenyl hydrogen silicone, tetrachlorophenyl silicone, methyl vinyl silicone, ethyl vinyl silicone, and the like are used.

Specific examples of chlorosilanes include tetrachlorosilane, trichlorosilane, trichloromethylsilane, dichlorodimethylsilane, chlorotrimethylsilane, trichloroethylsilane, dichlorodiethylsilane, and chlorotriethylsilane.
Specific examples of alkoxysilanes include tetramethoxysilane, tetraethoxysilane, etc .; quaternary alkoxysilanes, trimethoxymethylsilane, trimethoxyethylsilane, triethoxymethylsilane, triethoxyethylsilane, etc .; tertiary Secondary alkoxysilanes such as alkoxysilane, dimethoxydimethylsilane, dimethoxydiethylsilane, diethoxydimethylsilane, diethoxydiethylsilane, etc .; primary alkoxysilanes such as methoxytrimethylsilane, methoxytriethylsilane, ethoxytrimethylsilane, ethoxytriethylsilane, etc. Is used. A secondary or higher alkoxysilane is preferable, a tertiary or higher alkoxysilane is more preferable, and a quaternary alkoxysilane is more preferable.

Specific examples of siloxanes include hexamethyldisiloxane, hexaethyldisiloxane, pentamethyldisiloxane, tetramethyldisiloxane, and the like, with hexamethyldisiloxane being preferred.
Specific examples of the silazanes include hexamethyldisilazane, dipropyltetramethyldisilazane, diphenyltetramethyldisilazane, tetraphenyldimethyldisilazane and the like, and hexamethyldisilazane is preferable.

  The amount of the silylating agent relative to the zeolite is not particularly limited, but is usually 0.001 mol or more, preferably 0.01 mol or more, more preferably 0.1 mol or more with respect to 1 mol of the zeolite. It is. Moreover, it is 5 mol or less normally, Preferably it is 3 mol or less, More preferably, it is 1 mol or less. By making the amount of the silylating agent within the above range, it is preferable in that silylation coating on the outer surface acid sites can proceed efficiently and reduction in catalyst activity due to excessive silylation coating can be suppressed. The amount of the silylating agent is expressed in terms of the number of moles of Si atoms contained in the silylating agent. In the case of a silylating agent having a plurality of Si atoms in the molecule, the total number of moles of Si atoms is converted to silylation. It will be treated as the number of moles of agent.

  When performing liquid phase silylation, a solvent can be used, and the solvent is not particularly limited, but is a hydrocarbon such as hexane, heptane, octane, nonane, decane, cyclopentane, cyclohexane, benzene, toluene, xylene, etc. Or water can be used. When liquid phase silylation is performed with an aqueous solvent, an acidic aqueous solution to which an acid such as sulfuric acid or nitric acid is added can be used to promote the silylation reaction.

  When liquid phase silylation is performed, the concentration of the silylating agent in the solution for performing the liquid phase silylation reaction is not particularly limited, but is usually 0.01% by mass or more, preferably 0.5% by mass. As mentioned above, More preferably, it is 1 mass% or more. Moreover, it is 80 mass% or less normally, Preferably it is 60 mass% or less, More preferably, it is 40 mass% or less. By setting the concentration of the silylating agent within the above range, it is preferable in that condensation between the silylating agents can be suppressed and the silylation rate can be maintained.

The amount of the solvent relative to the zeolite in the liquid phase silylation is not particularly limited, but is usually 1 g or more, preferably 3 g or more, more preferably 5 g or more with respect to 1 g of the zeolite. Moreover, it is 100 g or less normally, Preferably it is 80 g or less, More preferably, it is 50 g or less. Setting the amount of the solvent in the above range is preferable in that sufficient stirring efficiency of the slurry can be obtained and a certain productivity can be ensured.

  When performing liquid phase silylation, a specific range of moisture may be imparted to the zeolite to be subjected to the silylation treatment. The moisture contained in the zeolite may be adjusted to a specific range by artificially supplying moisture even if the zeolite originally contains. Usually, the zeolite of the present invention is obtained by calcining the one obtained by hydrothermal synthesis, and further converting to the ammonium type and then calcining if necessary, and then converting to the proton type. Therefore, it is usually assumed that the water content of the zeolite before the silylation treatment is usually very low, and may be subjected to the silylation treatment as it is, or water is supplied so that the zeolite has a specific water content, You may use it, adjusting water content (henceforth a humidity control process).

  The water content is not particularly limited, but represents the weight of water contained in the zeolite in terms of mass% based on the weight of the dry zeolite, and is usually 30 mass% or less, preferably 25 mass% or less. Is 0% by mass in a completely dry state. By setting the water content within the above range, it is preferable in that silylation coating on the outer surface acid sites can proceed efficiently and pore blockage due to excessive silylation can be prevented.

  The humidity control method is not particularly limited as long as it can be adjusted to a predetermined moisture content. For example, a method in which the zeolite is left in an atmosphere having an appropriate relative humidity, a method in which the zeolite is allowed to coexist with a saturated aqueous solution of water or an inorganic salt in a sealed container (such as a desiccator), and left in a saturated water vapor atmosphere, zeolite In addition, a method of circulating a gas having an appropriate water vapor pressure may be used. In the above method, in order to perform more uniform humidity control, the humidity control process may be performed while mixing or stirring the zeolite.

  The temperature for the silylation treatment is appropriately adjusted according to the type of silylating agent and solvent to be used, and is not particularly limited, but is usually 20 ° C or higher, preferably 40 ° C or higher, more preferably 60 ° C or higher. . Moreover, it is 140 degrees C or less normally, Preferably it is 120 degrees C or less, More preferably, it is 100 degrees C or less. By setting the silylation treatment temperature within the above range, water discharge in the zeolite pores is suppressed, so that the silylation coating of the outer surface acid sites can proceed efficiently and the silylation rate can be maintained. This is preferable.

  The time required to raise the temperature to the silylation temperature after adding the silylating agent is not particularly limited, and the silylating agent may be added at the silylation temperature, but is usually 0.01 hours. As described above, preferably 0.05 hours or more, more preferably 0.1 hours or more, and there is no particular upper limit for the time required for temperature increase. When the silylation temperature is high, by setting the time required for the temperature rise to the above range, the water discharge from the pores of the zeolite is suppressed, so the hydrolysis and polymerization reaction of the silylating agent in the solution Is preferable in that the silylation of the zeolite proceeds efficiently.

  The treatment time for silylation depends on the reaction temperature, but is usually 0.1 hour or longer, preferably 0.5 hour or longer, more preferably 1 hour or longer, as long as the performance of the catalyst is not impaired. There is no upper limit. By setting the treatment time within the above-mentioned range, it is preferable in that silylation coating of the outer surface acid sites of the zeolite proceeds and the outer surface acid amount is sufficiently reduced.

(Steam treatment)
The steam treatment method for the AEI zeolite of the present invention is not particularly limited, but can be brought into contact with a gas containing steam within a range not impairing the effects of the present invention. Specific examples include a reaction atmosphere containing water vapor with at least one selected from water vapor, water diluted with air or an inert gas, ethylene and ethanol, or a reaction atmosphere for producing water vapor. The reaction that generates water vapor is a reaction that generates water vapor by dehydration, such as the dehydration reaction of ethanol. Although the water vapor may partially exist as liquid water depending on the conditions, it is preferable that the whole be present in the state of water vapor in order to give the zeolite a uniform water vapor treatment effect.

  The zeolite is thought to decrease not only the amount of acid on the outer surface but also the total amount of acid because the elimination of heterometallic atoms forming the skeleton occurs throughout the crystal by steam treatment. This reduction in the total acid amount suppresses the formation of coke inside the pores of the zeolite and improves the intracrystalline diffusivity. For this reason, it is presumed that the production of linear butene having a molecule larger than that of propylene is relatively accelerated.

If excessive steam treatment is performed, the intracrystalline diffusivity increases more than necessary, and the amount of hydrocarbon molecules having 5 or more carbon atoms such as pentene and hexene tends to increase.
Although the water vapor treatment temperature of the zeolite is not particularly limited, it is usually 400 ° C. or higher, preferably 500 ° C. or higher, more preferably 550 ° C. or higher. Moreover, it is 1200 degrees C or less normally, Preferably it is 1000 degrees C or less, More preferably, it is 900 degrees C or less. By setting the steam treatment temperature within the above range, it is preferable in that the heterometal atoms can be efficiently removed from the skeleton in a short treatment time without causing the skeleton structure to collapse.

  The water vapor (steam) used for the water vapor treatment can be diluted with an inert gas such as air, helium or nitrogen. The water vapor concentration at that time is not particularly limited, but is usually 3% by volume or more, preferably 5% by volume or more, more preferably 10% by volume or more based on the total gas used when the zeolite is steam-treated. The upper limit is not particularly limited, and 100% by volume of water vapor can be used. By setting the water vapor concentration in the above range, it is preferable in that the T atoms can be efficiently removed from the skeleton in a short processing time.

The water vapor treatment time of the zeolite is not particularly limited, but is usually 0.1 hour or longer, preferably 0.5 hour or longer, more preferably 1 hour or longer. Further, there is no upper limit of the treatment time as long as the catalyst activity is not significantly inhibited. The treatment time can be appropriately adjusted depending on the steam treatment temperature and the water vapor concentration.
The water vapor treatment of the zeolite may be performed in a state where organic substances are present inside the pores. The presence of organic substances inside the pores makes it possible to greatly reduce the acid points on the outer surface while preventing an extreme decrease in the acid points inside the pores, particularly when a strong steam treatment is performed.

  Although it does not specifically limit as said organic substance, The structure directing agent used at the time of the hydrothermal synthesis of a zeolite, the coke produced | generated by reaction, etc. are mentioned. These organic substances can be removed by performing a steam treatment on the hydrothermally synthesized zeolite (hereinafter sometimes referred to as “zeolite before calcination”) and then through a combustion process such as air calcination, or an oxygen-containing gas such as air. By treating with water vapor diluted with, water vapor treatment can be performed while removing organic substances.

  It is also possible to physically mix the zeolite with a compound containing an alkaline earth metal before subjecting the zeolite to steam treatment. By adding an alkaline earth metal, the strong acid point of the zeolite may be neutralized and the production of coke generated at the strong acid point may be suppressed. Examples of the compound containing an alkaline earth metal include calcium carbonate, calcium hydroxide, and magnesium carbonate, among which calcium carbonate is preferable.

  The amount of the compound containing an alkaline earth metal is not particularly limited, but is usually 0.5% by mass or more, preferably 3% by mass or more, and usually 45% by mass or less, preferably 40% by mass or less with respect to the zeolite. is there.

(Heat treatment)
The method for heat-treating the AEI zeolite of the present invention is not particularly limited. Specifically, the zeolite is subjected to a high-temperature treatment in at least one atmosphere selected from air and an inert gas, Examples thereof include a method of performing high-temperature treatment in a mixed gas atmosphere containing at least one selected from ethylene and ethanol.

In the heat treatment of the zeolite, as in the case of the steam treatment, the total acid amount due to the elimination of the hetero metal atoms in the skeleton can be reduced.
The heat treatment temperature is not particularly limited, but is usually 600 ° C. or higher, preferably 700 ° C. or higher, usually 1200 ° C. or lower, preferably 1000 ° C. or lower. By setting the heat treatment temperature within the above range, it is preferable in that the T atoms can be efficiently removed from the skeleton in a short treatment time without causing the skeleton structure to collapse.

As the gas species used in the heat treatment, helium, nitrogen, air, or the like can be used.
The heat treatment may be performed in a state where organic substances are present in the pores, similarly to the steam treatment. When an inert gas such as helium or nitrogen is used, the organic substance may be carbonized by heat treatment, but can be removed by firing with air.

The heat treatment may be performed simultaneously with the calcination performed when the above zeolite is produced or separately. The heat treatment is performed at a relatively high temperature for the purpose of desorption of the T atom in the skeleton, and is not particularly limited. Specifically, if the above baking and heat treatment are performed separately, The heat treatment is usually performed at a higher temperature than the firing.
The heat treatment time is not particularly limited, but is usually 0.1 hour or longer, preferably 0.5 hour or longer, and more preferably 1.0 hour or longer. Further, there is no upper limit of the treatment time as long as the catalyst activity is not significantly inhibited, and the treatment time can be appropriately adjusted depending on the heat treatment temperature.

(Acid treatment)
The method for acid treatment of the AEI zeolite of the present invention is not particularly limited, and specific examples include a method using an acidic aqueous solution.
The type of acid used in the acidic aqueous solution is not particularly limited, but includes inorganic acids such as sulfuric acid, nitric acid, hydrochloric acid, and phosphoric acid, carboxylic acids such as formic acid, acetic acid, and propionic acid, oxalic acid, and malonic acid. The dicarboxylic acid can be used. Of these, sulfuric acid, nitric acid, and hydrochloric acid are preferable.

  The acid concentration of the acidic aqueous solution is not particularly limited, but is usually 0.01M or more, preferably 0.1M or more, more preferably 1M or more, and usually 10M or less, preferably 8M or less. More preferably, it is 6M or less. By setting the acid concentration within the above range, it is preferable in that the T atom can be efficiently removed from the skeleton in a short processing time without causing the skeleton structure to collapse.

  The amount of the acidic aqueous solution with respect to the zeolite is not particularly limited, but is generally 3 g or more, preferably 5 g or more, more preferably 10 g or more, and usually 100 g or less, based on the total amount of the acidic aqueous solution with respect to 1 g of zeolite. Preferably it is 80 g or less, More preferably, it is 50 g or less. Setting the amount of the acidic aqueous solution in the above range is preferable in that sufficient stirring efficiency of the slurry can be obtained and a certain productivity can be ensured.

The temperature of the acid treatment is not particularly limited, but it can be usually from room temperature to 100 ° C. at normal pressure and 100 ° C. or higher in a pressure vessel, and is usually 40 ° C. or higher, preferably 60 ° C. or higher. , More preferably 80 ° C. or higher, usually 200 ° C. or lower, preferably 18
0 ° C. or lower, more preferably 160 ° C. or lower. By setting the acid treatment temperature within the above range, it is possible to efficiently remove heterometal atoms from the skeleton in a short time while suppressing the collapse of the skeleton structure.

The treatment time of the acid treatment is not particularly limited and depends on the acid concentration and the reaction temperature, but is usually 0.01 hours or more, preferably 0.1 hours or more, as long as the performance of the catalyst is not impaired. There is no particular upper limit on the processing time. The treatment time can be appropriately adjusted depending on the acid concentration and the reaction temperature.
By adding a silylating agent to the acidic aqueous solution, the acid treatment and the silylation treatment can be performed simultaneously. The silylating agent used in that case is the same as the silylating agent.

(Metal ion exchange)
The counter cation of the hetero metal atom of the zeolite is usually an alkali metal such as sodium, ammonium (NH ₄ ) or proton (H). These counter cations can be ion-exchanged, and can be used after appropriately exchanging metal ions.
The metal to be exchanged is not particularly limited, but includes alkali metals such as lithium, sodium, potassium, rubidium and cesium, and alkaline earth metals such as magnesium, calcium, strontium and barium, preferably sodium, Potassium, magnesium and calcium.

The method of metal ion exchange is not particularly limited, but can be performed by a known ion exchange method. The cation of the zeolite used in the ion exchange method is not particularly limited, and a sodium type, an ammonium type, or a proton type is usually used.
As the metal source, nitrates, sulfates, acetates, carbonates, chloride salts, bromide salts, iodide salts and the like are usually used, preferably nitrates, sulfates, chloride salts, more preferably nitrates. It is.

The solvent to be used is not particularly limited as long as the metal source dissolves, but water is usually used.
The concentration of the metal source solution is not particularly limited, but is usually 0.1M or more, preferably 0.5M or more, more preferably 1M or more, and the upper limit is usually 10M or less, preferably 8M or less, More preferably, it is 6M or less. It is desirable to adjust the concentration according to the solubility of the metal source.

The temperature at which ion exchange is performed is from room temperature to the boiling point of the solvent. The treatment time may be a time for the ion exchange to sufficiently reach equilibrium, and is usually about 1 to 6 hours. In order to increase the metal exchange rate, it is also possible to repeat ion exchange a plurality of times.
Separation of the zeolite from the suspension treated for a predetermined time is performed by a normal solid-liquid separation operation such as filtration or centrifugation.

The atmosphere at the time of drying the zeolite after ion exchange is not particularly limited. The drying temperature is usually from room temperature to the boiling point of the solvent.
The zeolite after ion exchange is used after being appropriately calcined. The firing temperature should just be higher than the decomposition temperature of a metal source, and is 200 degreeC-600 degreeC normally, Preferably it is 300 degreeC-500 degreeC. If the calcination temperature is too low, the metal source tends to remain, and if the calcination temperature is too high, the zeolite structure collapse and metal sintering tend to proceed.

The catalytically active component may be used as it is in the reaction as a catalyst, or may be used in the reaction by granulating / molding using a substance or binder inactive to the reaction, or by mixing them. Examples of the substance or binder inert to the reaction include alumina or alumina sol, silica, silica sol, quartz, and a mixture thereof.
In addition, the composition of the above-described catalytically active component is a composition of only the catalytically active component that does not contain a substance or a binder inactive to these reactions. Therefore, in the present invention, when a substance or binder that is inert to these reactions is included, the catalytically active component and the substance or binder that is inert to these reactions are collectively referred to as a catalyst. In the case where no inactive substance or binder is contained, only the catalytically active component is referred to as a catalyst.

  The particle size of the catalyst varies depending on the zeolite synthesis conditions, but is usually 0.01 μm to 10 μm as the average particle size. If the particle size is too large, the effectiveness factor of the catalyst tends to decrease, and if it is too small, the handleability is inferior. This average particle diameter can be determined by SEM observation or the like.

(Organic compound raw material)
The organic compound raw material of the present invention is not particularly limited, and examples thereof include oxygenates such as methanol, dimethyl ether, ethanol and acetone, and olefins such as ethylene, propylene, butene, pentene and hexene, preferably methanol, Dimethyl ether, ethanol, and ethylene are preferable, ethanol and ethylene are more preferable, and ethylene is more preferable.

  The origin of production of methanol and dimethyl ether which are raw materials of the present invention is not particularly limited. For example, those obtained by hydrogenation reaction of coal and natural gas, and CO / hydrogen mixed gas derived from by-products in the steel industry, those obtained by reforming reaction of plant-derived alcohols, those obtained by fermentation method And those obtained from organic materials such as recycled plastic and municipal waste. At this time, a state in which compounds other than methanol and dimethyl ether resulting from each production method are arbitrarily mixed may be used as it is, or a purified one may be used.

  Ethylene which is a raw material of the present invention is not particularly limited. For example, ethylene produced by catalytic cracking or steam cracking from petroleum sources, ethylene obtained by performing Fischer-Tropsch synthesis using hydrogen / CO mixed gas obtained by gasification of coal as raw material, or ethane dehydrogenation or Ethylene obtained by oxidative dehydrogenation, ethylene obtained by metathesis reaction and homologation reaction, ethylene obtained by MTO (Methanol to Olefin) reaction, ethylene obtained by dehydration reaction of ethanol, ethylene obtained by oxidative coupling of methane, Ethylene obtained by other various known methods can be arbitrarily used. At this time, a state in which a compound other than ethylene resulting from various production methods is arbitrarily mixed may be used as it is, or purified ethylene may be used, but purified ethylene is preferable.

  Ethanol which is a raw material of the present invention is not particularly limited. For example, those obtained by various known methods such as those produced by hydration reaction of ethylene, those produced from synthesis gas, and those produced by fermentation using plant-derived polysaccharides as raw materials are arbitrarily used. In this case, a compound in which a compound (particularly water) resulting from each production method is arbitrarily mixed may be used as it is, or purified ethanol may be used.

Ethanol is easily dehydrated and converted to ethylene by the acid sites present in the zeolite of the present invention. Therefore, ethanol may be directly introduced into the reactor as a raw material. Hereinafter, the production method using ethanol as a raw material will be handled in the same manner as the production method using ethylene as a raw material on the basis of ethylene converted by dehydration.
As a raw material of the present invention, a mixture of ethylene and ethanol may be used. For example, a mixture of ethylene and ethanol obtained by a partial dehydration reaction of ethanol, or a mixture obtained by mixing ethylene and ethanol in an arbitrary ratio can be used.

The raw material of the present invention is preferably ethylene rather than ethanol or a mixture of ethylene and ethanol. When ethanol is used as a raw material, the catalyst may be deteriorated or coking may be promoted by water generated during the reaction. In terms of cost, ethylene is preferable because it is cheaper than ethanol.
In addition to ethylene and / or ethanol, oxygenates such as methanol, dimethyl ether and acetone, and olefins such as propylene, butene, pentene and hexene may be contained in the raw material.

(Lower olefin)
The lower olefin produced in the present invention is an olefin having 2 to 4 carbon atoms, specifically ethylene, propylene and butenes, preferably propylene and butenes, more preferably propylene and linear butenes. It is. When AEI zeolite obtained by the production method of the present invention is used, propylene and linear butene can be obtained in high yield.

(Reaction conditions)
When producing propylene and linear butene using ethylene as a raw material, the olefin contained in the reactor outlet gas may be recycled to the reactor inlet. The olefin to be recycled is usually ethylene, but other olefins may be recycled. The olefin used as a raw material is preferably a lower olefin, and a branched olefin is not preferred because it is difficult to enter the pores of the zeolite of the present invention because of its molecular size. The lower olefin is preferably ethylene, but propylene or linear butene may be recycled depending on the desired production ratio of propylene and linear butene.

  In the present invention, at least one raw material selected from ethylene and ethanol is brought into contact with the catalyst in the reactor, and the form of the reactor used for producing the lower olefin is not particularly limited, but is usually a continuous fixed bed reaction. Or a fluidized bed reactor is selected. Propylene and straight-chain butene are produced at a certain ratio because the propylene and straight-chain butene selectivity tend to fluctuate with the change in conversion when propylene and straight-chain butene are produced as lower olefins. For this, a fluidized bed reactor is preferred.

When packing the above-mentioned catalyst into the fluidized bed reactor, in order to suppress the temperature distribution of the catalyst layer to a small level, particles that are inert to the reaction such as quartz sand, alumina, silica, and silica-alumina are mixed with the catalyst. And may be filled. In this case, there is no particular limitation on the amount of granular material inert to the reaction such as quartz sand. In addition, it is preferable that a granular material is a particle size comparable as a catalyst from the surface of uniform mixing property with a catalyst.

In the reactor, in addition to ethylene, helium, argon, nitrogen, carbon monoxide, carbon dioxide, hydrogen, water (water vapor), paraffins, hydrocarbons such as methane, aromatic compounds, In addition, a gas inert to the reaction, such as a mixture thereof, can be present. Among them, it is preferable that hydrogen coexists.
There is no particular restriction on the concentration of ethylene (that is, the substrate concentration) in all the feed components fed to the reactor, but it is usually 5 mol% or more, usually 90 mol% or less, preferably 70 mol% or less. By setting the substrate concentration within the above range, the production of aromatic compounds and paraffins can be suppressed, and the yield of lower olefins can be improved. Further, since the reaction rate can be maintained, the amount of catalyst can be suppressed, and the size of the reactor can also be suppressed.

It is preferable to dilute ethylene with the above diluent as necessary so that the above substrate concentration is obtained.
When ethanol is used as a raw material, since ethanol is immediately converted to ethylene by dehydration as described above, the supplied ethanol can be handled in the same manner as when using the same mole of ethylene.

The space velocity in the reactor is not particularly limited, but is usually 0.01 Hr ⁻¹ or more, preferably 0.1 Hr ⁻¹ or more, usually 500 Hr ⁻¹ or less, preferably 100 Hr ⁻¹ or less. . By setting the space velocity within the above range, the proportion of unreacted ethylene in the reactor outlet gas can be reduced, and by-products such as aromatic compounds and paraffins can be reduced. It is preferable at the point which can improve a yield.

The space velocity (WHSV) mentioned here is a flow rate (weight / hour) of ethylene as a reaction raw material per weight of the catalyst (catalytic active component). Here, the catalyst weight is the weight of an inactive component used for granulation / molding of the catalyst and a catalytically active component that does not contain a binder.
The reaction temperature is not particularly limited as long as ethylene is in contact with the catalyst to produce a lower olefin, but is usually 200 ° C. or higher, preferably 300 ° C. or higher, and usually 700 ° C. or lower, preferably It is 600 degrees C or less. By making reaction temperature into the said range, the production | generation of an aromatic compound and paraffin can be suppressed, and the yield of a lower olefin can be improved. Further, since dealumination from the zeolite skeleton is suppressed, it is preferable in that the catalyst life can be maintained.

  The reaction pressure is not particularly limited, but is usually 1 kPa (absolute pressure, the same applies hereinafter) or more, preferably 50 kPa or more, more preferably 100 kPa or more. Moreover, it is 3 MPa or less normally, Preferably it is 1 MPa or less, More preferably, it is 0.7 MPa or less. By making reaction pressure into the said range, the production | generation of by-products, such as paraffins, can be suppressed and the yield of a lower olefin can be improved. The reaction rate can also be maintained.

  In the present invention, the ethylene conversion rate is not particularly limited, but the normal conversion rate is usually 50% or more, preferably 60% or more, more preferably 70% or more, usually less than 100%, Preferably it is 95% or less, More preferably, it is 90% or less. In the present invention, by adjusting the ethylene conversion rate to be in the above range, by-products of aromatic compounds and paraffins, and the accumulation of coke in the pores can be suppressed, and lower olefins can be collected. The rate can be improved and can be produced at a high linear butene / propylene ratio.

Usually, since the conversion rate of ethylene tends to decrease as the reaction time elapses, the catalyst that has been reacted for a certain period of time needs to be subjected to regeneration treatment. The method for operating in the above ethylene conversion range is not particularly limited.
For example, when the reaction is carried out in a fixed bed reactor, a plurality of reactors are provided in parallel, and when the ethylene conversion rate falls from the above preferred range, the contact between the catalyst and the reaction raw material is stopped. The catalyst is subjected to a regeneration step. In a fixed bed reactor, the reaction time and the regeneration time are appropriately adjusted, that is, the time for switching between the reaction step and the regeneration step in the operation is appropriately adjusted, thereby continuously operating at the ethylene conversion rate in the above preferred range. can do.

  When the reaction is carried out in a fluidized bed reactor, a catalyst regenerator is attached to the reactor, the catalyst extracted from the reactor is continuously sent to the regenerator, and the catalyst regenerated in the regenerator is removed. The reaction is preferably carried out while continuously returning to the reactor. By appropriately adjusting the residence time of the catalyst in the reactor and the residence time in the regenerator, the catalyst can be continuously operated at an ethylene conversion rate in the above preferred range.

The catalyst subjected to the reaction can be regenerated and used. Specifically, a catalyst having a reduced ethylene conversion can be regenerated using various known catalyst regeneration methods.
The regeneration method is not particularly limited. Specifically, for example, the regeneration can be performed using air, nitrogen, water vapor, hydrogen, or the like, and the regeneration is preferably performed using hydrogen (for example, Japanese Patent Application Laid-Open No. 2011-2011). Can be reproduced in accordance with the method described in Japanese Patent No. -78962.

Moreover, as a method for maintaining a high ethylene conversion rate for a long time, there is a method for suppressing coke accumulation in the catalyst by reacting ethylene in a hydrogen atmosphere described in JP-A-2011-79818.
As the reactor outlet gas (reactor effluent), a mixed gas containing a reaction product, a lower olefin, unreacted ethylene, a by-product, and a diluent is obtained. The concentration of the lower olefin in the mixed gas is not particularly limited, but is usually 1% by mass or more, preferably 2% by mass or more, and usually 95% by mass or less, preferably 80% by mass or less.

The mixed gas usually contains ethylene, but it is preferable that at least a part of the ethylene in the mixed gas is recycled to the reactor and reused as a reaction raw material.
Examples of by-products include olefins having 5 or more carbon atoms, paraffins, and aromatic compounds.

(Use of propylene)
Propylene obtained by the production method of the present invention can produce polypropylene by polymerizing it. The method for polymerizing propylene is not particularly limited, but the propylene obtained by the present invention can be directly used as a raw material monomer by introducing it into a polymerization reactor. Moreover, the propylene obtained by this invention can be utilized also as a raw material of propylene derivative products through the various reaction mentioned later besides a polypropylene. For example, acrylonitrile can be produced by ammonia oxidation, acrolein, acrylic acid and acrylate esters by selective oxidation, normal butyl alcohol by oxo reaction, propylene oxide, propylene glycol, etc. by selective oxidation. Propylene can produce acetone by the Wacker reaction, and methyl isobutyl ketone can be produced from the obtained acetone. Further, methyl methacrylate can be produced from acetone via acetone cyanohydrin. Propylene can produce isopropyl alcohol by a hydration reaction. Propylene can be produced by reacting with benzene, and can be used to produce phenol, bisphenol A, or polycarbonate resin using cumene as a raw material.

(Application of linear butene)
The linear butene obtained by the production method of the present invention can produce butadiene by dehydrogenation. Furthermore, butadiene can produce polybutadiene (BR) by homopolymerization, styrene butadiene rubber (SBR) by polymerization with styrene, acrylonitrile-styrene-butadiene resin (ABS resin) by polymerization of acrylonitrile and styrene, and the like. Linear butene can also be used as a raw material for other butene derivatives. For example, linear butene can produce methyl ethyl ketone through sec-butyl alcohol by the indirect hydration method and subsequent dehydrogenation reaction. 1-butene can produce polybutene-1 by polymerization, amyl alcohol or the like by oxo reaction.

  The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to the following examples as long as the gist thereof is not exceeded.

In the following preparation examples, the X-ray diffraction (XRD) pattern of the zeolite crystal obtained by synthesis was obtained using X'Pert Pro MPD manufactured by PANalytical. The X-ray source is CuKα (X-ray output: 40 kV, 30 mA), and the reading width is 0.016 °. The composition of the synthesized zeolite was measured by fluorescent X-ray analysis. For the measurement, Rayny EDX-700 manufactured by Shimadzu Corporation was used. The shape of the particles was observed at an accelerating voltage of 15 kV on the sample subjected to the conductive treatment using a scanning electron microscope (S-4100) manufactured by Hitachi High-Tech.

<Example 1>
0.040 g of sodium hydroxide was dissolved in 3.21 g of water, and 1.28 g of Y-type zeolite CBV720 (SiO ₂ / Al ₂ O ₃ ratio 30, manufactured by ZEOLYST) was added and stirred for 2 hours to obtain a mixture. . The mixture was charged into a 100 ml autoclave and subjected to a pretreatment for heating at 160 ° C. for 20 hours while rotating at 15 rpm under self-pressure. The obtained pretreatment mixture was mixed with 5.12 g of an aqueous N, N-dimethyl-3,5-dimethylpiperidinium hydroxide solution (21.8 wt%), 0.120 g of sodium hydroxide, AEI type zeolite (SiO ₂ / Al ₂ O ₃ ratio 20, average particle size 1.5 μm, including organic structure directing agent) 0.120 g corresponding to 10% by mass is added as a seed crystal, and the mixture is stirred. Obtained. The mixture was charged into a 100 ml autoclave and subjected to a hydrothermal synthesis reaction at 160 ° C. for 7 days while rotating at 15 rpm under autogenous pressure. The obtained product was filtered and washed with water, and then dried at 100 ° C. to obtain 0.65 g of a white powder.
From the XRD pattern of the product (FIG. 1), it was confirmed that the obtained product was an AEI zeolite. Further, the ratio of SiO ₂ / Al ₂ O ₃ was 18 from the fluorescent X-ray analysis. Moreover, the average particle diameter was 125 nm from the scanning electron microscope (FIG. 2).

<Example 2>
0.040 g of sodium hydroxide and 5.12 g of an aqueous solution of N, N-dimethyl-3,5-dimethylpiperidinium hydroxide (21.8 wt%) were dissolved in 1.40 g of water in this order, and Y-type zeolite CBV720 1.28 g (SiO ₂ / Al ₂ O ₃ ratio 30, ZEOLYST) was added and stirred for 2 hours. Further, 0.060 g of CHA-type zeolite (SiO ₂ / Al ₂ O ₃ ratio 25, average particle diameter 200 nm, not including an organic structure directing agent) corresponding to 5% by mass with respect to the weight of silica was added as a seed crystal and stirred. To obtain a mixture. The mixture was charged into a 100 ml autoclave and subjected to a hydrothermal synthesis reaction at 160 ° C. for 7 days while rotating at 15 rpm under self-pressure. The obtained product was filtered and washed with water, and then dried at 100 ° C. to obtain 0.96 g of a white powder.
From the XRD pattern of the product (FIG. 3), it was confirmed that the obtained product was an AEI zeolite. From the X-ray fluorescence analysis, the SiO ₂ / Al ₂ O ₃ ratio was 22. Moreover, the average particle diameter was 110 nm from the scanning electron microscope (FIG. 4).

<Example 3>
0.097 g of sodium hydroxide and 3.58 g of N, N-dimethyl-3,5-dimethylpiperidinium hydroxide aqueous solution (21.8 wt%) were dissolved in 0.28 g of water in this order, and aluminum hydroxide ( Silica sol SI-30 (SiO ₂ 30.5 wt%, Na ₂ O 0.4 wt%, JGC catalyst) as a silica source after adding 0.178 g of aluminum oxide 50 to 57 wt%, manufactured by Aldrich) and mixing. 2.76 g (made by Kasei Co., Ltd.) was added and stirred sufficiently. Furthermore, 0.168 g of AEI zeolite (SiO ₂ / Al ₂ O ₃ ratio 22, average particle diameter 110 nm, including organic structure directing agent) of 20 wt% with respect to the added SiO ₂ is added as a seed crystal and further stirred. Gave a mixture. The mixture was charged into a 100 ml autoclave and subjected to a hydrothermal synthesis reaction at 160 ° C. for 7 days while rotating at 15 rpm under self-pressure. The obtained product was filtered and washed with water, and then dried at 100 ° C. to obtain 0.99 g of a white powder.
From the XRD pattern of the product (FIG. 5), it was confirmed that the obtained product was an AEI zeolite. From the X-ray fluorescence analysis, the SiO ₂ / Al ₂ O ₃ ratio was 14. Moreover, the average particle diameter was 90 nm from the scanning electron microscope (FIG. 6).

<Comparative Example 1>
0.160 g of sodium hydroxide and 5.12 g of an aqueous solution of N, N-dimethyl-3,5-dimethylpiperidinium hydroxide (21.8% by mass) are sequentially dissolved in 1.40 g of water, and Y-type zeolite CBV720 1.28 g (SiO ₂ / Al ₂ O ₃ ratio 30, ZEOLYST) was added and stirred for 2 hours. Furthermore, 0.120 g of AEI zeolite (SiO ₂ / Al ₂ O ₃ ratio 20, average particle diameter 1.5 μm, including organic structure directing agent) corresponding to 10% by mass with respect to the weight of silica was added as a seed crystal, The mixture was obtained by stirring. The mixture was charged into a 100 ml autoclave and subjected to a hydrothermal synthesis reaction at 160 ° C. for 7 days while rotating at 15 rpm under autogenous pressure. The obtained product was filtered and washed with water, and then dried at 100 ° C. to obtain 0.72 g of a white powder.
From the XRD pattern of the product (FIG. 7), the obtained product was a mixed phase of AEI phase and ANA phase. Moreover, the average particle diameter was 1.5 micrometers from the scanning electron microscope.

<Comparative Example 2>
The same method and conditions as in Example 2 except that CHA-type zeolite (SiO ₂ / Al ₂ O ₃ ratio 25, average particle size 200 nm) containing 0.08 g of sodium hydroxide containing an organic structure directing agent as seed crystals was used. A mixture was prepared and subjected to a hydrothermal synthesis reaction. The obtained product was filtered and washed with water, and then dried at 100 ° C. to obtain 0.81 g of a white powder.
From the XRD pattern of the product (FIG. 8), the obtained product was a mixed phase of AEI phase, FAU phase and CHA phase.

<Comparative Example 3>
A mixture was prepared in the same manner and under the same conditions as in Example 3, except that AEI zeolite (SiO ₂ / Al ₂ O ₃ ratio 20 including an organic structure directing agent) having an average particle size of 1.5 μm was used as a seed crystal. And subjected to a hydrothermal synthesis reaction. The obtained product was filtered and washed with water, and then dried at 100 ° C. to obtain 0.86 g of a white powder.
From the XRD pattern of the product (FIG. 9), the obtained product was a mixed phase of an amorphous phase and an AEI phase.

<Example 4>
A mixture was prepared and subjected to a hydrothermal synthesis reaction in the same manner and under the same conditions as in Example 2 except that 0.080 g of sodium hydroxide was used. The obtained product was filtered and washed with water, and then dried at 100 ° C. to obtain 0.96 g of a white powder.
From the XRD pattern of the product (FIG. 10), it was confirmed that the obtained product was an AEI zeolite. From the X-ray fluorescence analysis, the SiO ₂ / Al ₂ O ₃ ratio was 20. Moreover, the average particle diameter was 270 nm from the scanning electron microscope (FIG. 11).

<Example 5>
The same method and conditions as in Example 2 except that 0.080 g of sodium hydroxide and 3.65 g of an aqueous solution of N, N-dimethyl-3,5-dimethylpiperidinium hydroxide (21.8% by weight) were used. A mixture was prepared and subjected to a hydrothermal synthesis reaction. The obtained product was filtered and washed with water, and then dried at 100 ° C. to obtain 1.04 g of a white powder.
From the XRD pattern of the product (FIG. 12), it was confirmed that the obtained product was an AEI zeolite. From the X-ray fluorescence analysis, the SiO ₂ / Al ₂ O ₃ ratio was 21. Moreover, the average particle diameter was 180 nm from the scanning electron microscope (FIG. 13).

In Example 1, when heating pretreatment was performed before adding the quaternary ammonium salt, AEI zeolite having an average particle diameter of 125 nm was obtained in a single phase. On the other hand, in Comparative Example 1, when subjected to the hydrothermal synthesis reaction as it is without performing the pre-heating treatment before adding the quaternary ammonium salt, it becomes a mixed phase of AEI phase and ANA phase, and further its average particle size Was 1.5 μm. Therefore, before adding the quaternary ammonium salt, the mixture is pre-heated to form zeolite unit units from the silica source and the heterometallic element source, and the generation of crystal nuclei after the addition of the quaternary ammonium salt. It is presumed that AEI zeolite with fine crystal was produced.
In Examples 2, 4, and 5, when CHA-type zeolite not containing an organic structure-directing agent was added as a seed crystal, AEI having an average particle diameter of 110 nm to 270 nm even if the amount of Na addition or the amount of organic structure-directing agent added was changed. Type zeolite was obtained. On the other hand, in Comparative Example 2, when CHA-type zeolite having the same average particle size and composition and containing an organic structure-directing agent was added as a seed crystal, it was a mixed phase of AEI phase, FAU phase and CHA phase. From this, it is presumed that the use of zeolite containing no organic structure directing agent as seed crystals promoted the dissolution of seed crystals and the generation of crystal nuclei in the mixture, resulting in the formation of fine crystal AEI zeolite. .
In Example 3, when aluminum hydroxide was used as the heterometallic element source and AEI zeolite having an average particle size of 110 nm was used as the seed crystal, an AEI zeolite having an average particle size of 90 nm was obtained. On the other hand, in Comparative Example 3, when AEI zeolite having an average particle size of 1.5 μm was used as a seed crystal, the amorphous phase was the main component. Therefore, by using aluminum hydroxide, which has relatively low solubility as the aluminum source, and using fine zeolite as a seed crystal, which is likely to generate crystal nuclei, the generation of crystal nuclei rather than crystal growth occurs at the beginning of the reaction. Since it is advantageous, it is presumed that fine crystal AEI zeolite was produced.

<Example 6>
The AEI zeolite obtained in Example 2 was calcined at 580 ° C. for 6 hours under air flow to obtain Na-type aluminosilicate. Next, 1 g of the above zeolite was treated at 800 ° C. for 5 hours under normal pressure and 50% steam (steam / air = 50/50 (volume / volume)) circulation to obtain a steam-treated AEI zeolite. . Using this as a catalyst, a synthesis reaction of propylene and linear butene (lower olefin) was carried out using ethylene as a raw material. For the reaction, a normal pressure fixed bed flow reactor was used, and a quartz reaction tube having an inner diameter of 6 mm was filled with a mixture of the catalyst 100 mg and quartz sand 400 mg. Ethylene and nitrogen were supplied to the reactor so that the space velocity of ethylene was 0.36Hr ⁻¹ , 30% by volume of ethylene and 70% by volume of nitrogen, and synthesis of propylene and linear butene was performed at 350 ° C. and 0.1 MPa. The reaction was carried out and the reactor outlet gas was analyzed by gas chromatography. As a result of analysis, Table 1 shows the reaction results 0.83 hours after the total selectivity of propylene and linear butene was 70% or more and linear butene / propylene reached the maximum.

<Comparative example 4>
123 g of 1M aqueous sodium hydroxide solution and 32.9 g of N, N-dimethyl-3,5-dimethylpiperidinium hydroxide aqueous solution (21.8% by mass) were sequentially dissolved in 8.2 g of water to obtain Y-type zeolite CBV720 ( (SiO ₂ / Al ₂ O ₃ ratio 30, manufactured by ZEOLYST) 1
4.4 g was added and stirred for 30 minutes. Furthermore, colloidal silica SI-30 (SiO ₂
14.8 g (30% by mass, 0.3% by mass of Na, manufactured by JGC Catalysts & Chemicals Co., Ltd.) was added to obtain a gel reaction solution, and the mixture was stirred for 2 hours. The mixture was charged in a 1000 ml autoclave and subjected to a hydrothermal synthesis reaction at 135 ° C. for 7 days while stirring at 150 rpm under an autogenous pressure. The obtained product was filtered, washed with water, and dried at 100 ° C.
From the XRD pattern of the product, it was confirmed that the obtained product was an AEI zeolite. From the X-ray fluorescence analysis, the SiO ₂ / Al ₂ O ₃ ratio was 18. Moreover, the average particle diameter was 800 nm from the scanning electron microscope.
The obtained AEI zeolite was calcined and steamed under the same method and conditions as in Example 6. Using this as a catalyst, with the same method and conditions as in Example 6, using ethylene as a raw material,
A synthesis reaction of propylene and linear butene (lower olefin) was performed. As a result of analysis, Table 1 shows the reaction results 0.83 hours after the total selectivity of propylene and linear butene was 70% or more and linear butene / propylene reached the maximum.

In Example 6, when an AEI zeolite having an average particle diameter of 110 nm was used, the propylene selectivity was 49.4%, the linear butene selectivity was 32.1%, and the paraffin selectivity (C1 to C4) was 6.1. %Met. On the other hand, in Comparative Example 4, when AEI zeolite having an average particle diameter of 800 nm was used, the propylene selectivity was 49.5%, the linear butene selectivity was 29.6%, and the paraffin selectivity (C1 to C4) was 10.2. %Met.
From this, it was found that, in the production of propylene and linear butene, by using microcrystalline AEI zeolite as a catalyst, paraffin formation and accompanying coke accumulation are suppressed, and linear butene selectivity is improved. This is thought to be because, in the AEI zeolite catalyst with a small average particle size, diffusibility of the hydrocarbon component in the crystal was improved, so that linear butene with a large molecular size was easily generated and coking was suppressed at the same time. It is done.

  The microcrystalline AEI zeolite having an average particle size of less than 400 nm of the present invention can be used for catalytic reactions such as lower olefin production reactions from organic compounds, and has high activity and high selectivity with little coking deterioration, and catalyst It can be used as a catalyst with excellent life.

Claims (12)

A zeolite containing silicon and at least one heterometallic element selected from the group consisting of aluminum, gallium, boron, and iron, the structure of which is International Zeolite
The code defined by Association (IZA) is AEI, and the average particle size is 400
An AEI zeolite characterized by being less than nm.   The AEI zeolite according to claim 1, wherein the heterometallic element contains at least aluminum.   The AEI zeolite according to claim 1 or 2, wherein the average particle diameter is less than 300 nm.   A mixture containing a silica source, a heterometallic element source containing at least one selected from the group consisting of aluminum, gallium, boron, and iron, an alkali metal element source and / or an alkaline earth metal element source, and water is heated. It has a hydrothermal synthesis process which adds a quaternary ammonium salt to the pretreatment process and the mixture obtained by the said pretreatment process, and makes a hydrothermal synthesis reaction, The any one of Claims 1-3 characterized by the above-mentioned. A method for producing the AEI zeolite according to Item.   A silica source, a heterometallic element source containing at least one selected from the group consisting of aluminum, gallium, boron, and iron, an alkali metal element source and / or an alkaline earth metal element source, a quaternary ammonium salt, and water And a hydrothermal synthesis step in which the mixture obtained by the pretreatment step is subjected to a hydrothermal synthesis reaction, and the temperature of the pretreatment step is 10 ° C. than the temperature of the hydrothermal synthesis step. The method for producing an AEI zeolite according to any one of claims 1 to 3, wherein the method is low.   A silica source, a heterometallic element source containing at least one selected from the group consisting of aluminum, gallium, boron, and iron, an alkali metal element source and / or an alkaline earth metal element source, a quaternary ammonium salt, and water Hydrothermal synthesis reaction by adding 0.1% by mass or more of seed crystals composed of zeolite containing no organic structure-directing agent or / and having an average particle diameter of less than 500 nm to the mixture containing The method for producing an AEI zeolite according to any one of claims 1 to 3, further comprising a step of:   The method for producing an AEI zeolite according to any one of claims 4 to 6, wherein the heterometallic element source contains FAU-type zeolite containing aluminum.   A silica source, an aluminum hydroxide, an alkali metal element source and / or an alkaline earth metal element source, a quaternary ammonium salt, a seed crystal not containing an organic structure directing agent or / and having an average particle size of less than 500 nm, and The method for producing an AEI zeolite according to any one of claims 1 to 3, further comprising a hydrothermal synthesis reaction of a mixture containing water. The method for producing an AEI zeolite according to claim 6 or 8, wherein the seed crystal is a zeolite having a 6-membered ring and / or an 8-membered ring as a secondary building unit. The hetero metal element source includes a FAU type zeolite containing aluminum, and the seed crystal is a zeolite having a 6-membered ring and / or an 8-membered ring as a secondary building unit. A method for producing AEI zeolite. A method for producing a lower olefin by bringing an organic compound raw material into contact with the AEI zeolite according to any one of claims 1 to 3.   The method for producing a lower olefin according to claim 11, wherein the organic compound raw material is ethylene, and the lower olefin is propylene and linear butene.