JP2013075276A - Method of manufacturing catalyst for manufacturing propylene, and method of manufacturing propylene - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low cost method of manufacturing a catalyst for manufacturing propylene in which the by-product of the component of C5 or more unsuitable as a recycle content is controlled, and propylene is manufactured in a high selectivity, and to provide an efficient method of manufacturing propylene by the catalyst for manufacturing propylene, in the method of manufacturing propylene in which a raw material is ethylene.SOLUTION: A zeolite that has a CHA type structure including moisture from 10-25 wt.% is performed by silylation processing under the presence of hydrocarbon solvent with high versatility, thereby the catalyst for manufacturing propylene including the zeolite having the CHA type structure that has been made silyl is manufactured. Propylene is efficiently manufactured by using the catalyst for manufacturing propylene.

Description

  The present invention relates to a method for producing a catalyst for producing propylene containing a zeolite having a silylated CHA type structure.

  Conventionally, as a method for producing propylene, a naphtha steam cracking method and a fluidized catalytic cracking method of vacuum gas oil have been generally carried out. However, in the steam cracking method, in addition to propylene, a large amount of ethylene is produced, and it is difficult to greatly change the production ratio of propylene and ethylene, so it is difficult to cope with changes in the supply-demand balance between propylene and ethylene. . Therefore, a technique for producing propylene with high yield using ethylene as a raw material has been desired.

  Patent Document 1 suggests that propylene can be obtained with high selectivity by using CHA-type zeolite having a silylated outer surface acid point as a catalyst and bringing ethylene into contact with the catalyst. It is considered that high propylene selectivity can be realized by covering the outer surface acid sites of the CHA-type zeolite by silylation, which suppresses reactions that do not have shape selectivity that occurs at the outer surface acid sites. It is done. However, there are the following problems in silylation of zeolite.

  In Patent Document 1, as a method for silylating a zeolite having a CHA type structure, various silylating agents are allowed to act on the zeolite. At that time, hexamethyldisiloxane is used as a solvent for the silylation reaction. However, hexamethyldisiloxane is a very expensive organic compound with low versatility, and the production cost of the catalyst is high. Therefore, it is difficult to employ it for the production of the catalyst on an industrial scale. At the time of industrialization, an inexpensive and preferable production method using a solvent has been demanded.

  On the other hand, as a method for silylating zeolite, in Patent Document 2, in the production of a catalyst for producing alkylbenzene, mordenite (MOR type zeolite: oxygen 12-membered ring and 8-membered ring pore) or clinoptyllite (HEU type zeolite: When a zeolite such as oxygen 10-membered ring and 8-membered ring pore) is treated with a silylating agent, an organic solvent is used as a reaction solvent, and a zeolite containing a certain amount of water is used. This suggests that the selectivity of desired alkylbenzenes is improved.

International Publication No. 2010/128644 JP-A-8-198781

  The present invention is an inexpensive and versatile catalyst for propylene production for producing propylene at a high selectivity in the production of silylated CHA-type zeolite used for the production of propylene using ethylene as a raw material in view of the above-described conventional technology. It is an object of the present invention to provide a high manufacturing method.

As a result of intensive studies to solve the above problems, the present inventors have silylated a zeolite having a CHA-type structure having a water content of 10% by weight to 25% by weight in the presence of a hydrocarbon solvent. By doing so, it was found that the outer surface acid sites can be coated with high efficiency. In addition, in the reaction in which the obtained CHA-type zeolite is used as a catalyst for propylene production and is brought into contact with ethylene and converted into propylene, by-product generation of components having 5 or more carbon atoms (hereinafter referred to as components having 5 or more carbon atoms) is further suppressed. The inventors have found that propylene can be produced with high selectivity, and have completed the present invention.

That is, the gist of the present invention is as follows.
[1] A method for producing a catalyst for propylene production comprising a silylation step of silylating a zeolite having a CHA type structure, wherein the water content is 10 wt% or more and 25 wt% in the presence of a hydrocarbon solvent in the silylation step. %. A method for producing a catalyst for producing propylene, comprising reacting a zeolite having a CHA type structure of not more than% with a silylating agent.
[2] The method for producing a catalyst for producing propylene according to the above [1], wherein the zeolite having the CHA structure has a SiO ₂ / Al ₂ O ₃ molar ratio of 5 or more and 300 or less. [3] The method for producing a catalyst for producing propylene according to the above [1] or [2], wherein the hydrocarbon solvent is any one of hexane, benzene, toluene and xylene.
[4] The production of a catalyst for producing propylene according to any one of the above [1] to [3], wherein the silylating agent is any one of silicone, chlorosilane, alkoxysilane, siloxane, and silazane. Method.
[5] The catalyst for producing propylene according to any one of [1] to [4], wherein the silylating agent is an alkoxysilane having at least two or more alkoxy groups in the molecule. Production method.
[6] A method for producing propylene, wherein propylene is produced by bringing ethylene into contact with the propylene production catalyst obtained by the method according to any one of [1] to [5].

  According to the present invention, an inexpensive and highly versatile production method can be provided by silylating a zeolite having a CHA type structure in the presence of a hydrocarbon solvent in the presence of a specific range of moisture. In addition, in the method for producing propylene by bringing ethylene into contact with the catalyst, it is possible to produce a propylene production catalyst capable of producing propylene at a higher selectivity while suppressing by-production of C5 or higher components. The by-product of the C5 or higher component causes a decrease in propylene yield, increases the amount of raw material used to ensure a certain production amount, and increases the propylene production cost. When recycling the reactor outlet gas, components having a molecular diameter of C5 or larger (especially those having a branched chain) have low diffusion efficiency into the CHA-type pores and the reaction efficiency is lowered. It is not preferable. In addition, when the reactor outlet gas containing a large amount of C5 or higher components is separated in the purification system without recycling, the larger the amount of by-products of C5 or higher components, the greater the load of separation and purification, and the higher the energy consumption. Therefore, the propylene production cost is increased. By using the catalyst obtained by the method of the present invention, the by-production of C5 or higher components is suppressed, the separation and purification load is reduced, and the propylene production cost can be reduced.

Below, the typical aspect for implementing this invention is demonstrated concretely, However, This invention is not limited to the following aspects, unless the summary is exceeded.
The method for producing a catalyst for producing propylene according to the present invention is characterized by reacting a zeolite having a CHA type structure containing 10% by weight or more and 25% by weight or less of water in the presence of a hydrocarbon solvent with a silylating agent. .

Hereinafter, the components in the present invention will be described.
(1) Zeolite having a CHA type structure First, the physical properties of a zeolite having a CHA type structure (hereinafter sometimes referred to as “CHA type zeolite”) used in the method of the present invention will be described.
<Structure>
In the present invention, the CHA structure refers to a CHA structure, which is a code that defines the structure of the zeolite defined by the International Zeolite Association (hereinafter sometimes referred to as “IZA”). This is a zeolite having a crystal structure equivalent to that of naturally occurring chabazite.

<Physical properties>
A zeolite having a CHA structure has a structure characterized by having three-dimensional pores composed of oxygen 8-membered rings having a diameter of 3.8 × 3.8 mm, and the structure is characterized by X-ray diffraction data. . Further, the framework density is 14.5T / 1000Å ^3. The framework density here means the number of atoms constituting a skeleton other than oxygen per 1000 ³ of the zeolite, and this value is determined by the structure of the zeolite. The relationship between framework density and zeolite structure is shown in Atlas of Zeolite Framework Types, 6th revised edition, 2007.

The particle size of the CHA-type zeolite in the present invention is not particularly limited, but usually the total pore volume in the range of 100 to 200 μm of the pore size distribution obtained by the BJH method by the measurement method described below is used. Usually, it is 10 × 10 ⁻³ ml / g or more, preferably 20 × 10 ⁻³ ml / g or more, more preferably 30 × 10 ⁻³ ml / g or more. There is no particular upper limit, and it is usually 100 × 10 ⁻³ ml / g or less. This value is considered to be due to the grain boundary. A large value is considered to have a small particle size, and a small value is considered to have a large particle size. If this value is less than the lower limit, the particle size is large, so when used as a catalyst, the reaction substrate cannot sufficiently enter the inside of the pores, and the utilization rate of zeolite is considered to decrease, and the activity per catalyst weight is reduced. Decreases. Moreover, since the outer surface area per weight is small, the silylation may proceed excessively, possibly blocking the pores. If the upper limit is exceeded, the particle size is so small that it may be difficult to separate the zeolite and the solvent after silylation.

  The method for measuring the pore diameter is not particularly limited. Usually, nitrogen is used as the adsorption gas, and the nitrogen adsorption isotherm is obtained by measuring the equilibrium adsorption amount at the time of adsorption and desorption at the relative pressure at the liquid nitrogen temperature. The cumulative pore volume is calculated by the BJH method from the measured isotherm. Details will be described in Examples.

The total acid amount of the zeolite in the present invention (hereinafter sometimes simply referred to as the total acid amount) is the total acid amount of the zeolite, specifically, the total acid amount on the outer surface and inside the pores. Say.
The total acid amount of zeolite is measured by adsorbing a substance that can be selectively adsorbed on the acid sites of the zeolite and also entering the pores, and quantifying the adsorbed amount. be able to. The substance is not particularly limited, and specifically, ammonia can be used.
The method for quantifying the amount of adsorbed ammonia is not particularly limited, but it can usually be measured by the following procedure. As a pretreatment, the zeolite is dried and then contacted with ammonia vapor. Subsequently, excess ammonia is removed to obtain zeolite adsorbed with ammonia. The amount of ammonia desorbed per unit weight of the zeolite adsorbed with ammonia can be measured by a temperature programmed desorption method (hereinafter referred to as “TPD”) to determine the total acid amount.

Although the total acid amount is not particularly limited, it is usually 4.8 mmol / g or less, preferably 2.8 mmol / g or less. Moreover, it is 0.15 mmol / g or more normally, Preferably it is 0.30 mmol / g or more. When the upper limit is exceeded, when the zeolite is used as a catalyst for the hydrocarbon conversion reaction, deactivation due to coke formation is accelerated, the metal is easily removed from the skeleton (so-called dealumination), and the acid strength per acid point is weak. If the amount is less than the lower limit, the amount of acid is small, and the activity as a catalyst tends to decrease.

The outer surface acid amount of the zeolite in the present invention (hereinafter sometimes simply referred to as an outer surface acid amount) represents the total amount of acid sites present on the outer surface of the zeolite.
The amount of acid on the outer surface can be measured by adsorbing a substance that can be selectively adsorbed on the acid sites of the zeolite and cannot enter the inside of the zeolite pores, and quantifying the adsorbed amount. it can. Although the said substance is not specifically limited, Specifically, a pyridine can be used.
The method for determining the amount of pyridine adsorbed is not particularly limited, but it can usually be measured by the following procedure. As a pretreatment, the zeolite is dried and then contacted with pyridine vapor. Subsequently, excess pyridine is removed to obtain zeolite adsorbed with pyridine. The amount of pyridine desorbed per unit weight of the zeolite adsorbed with pyridine can be measured by a temperature programmed desorption method to determine the amount of acid on the outer surface.
The amount of acid on the outer surface is not particularly limited, but is usually 0.6 mmol / g or less, preferably 0.3 mmol / g or less. If the upper limit is exceeded, when the zeolite is used as a catalyst, a reaction that is not shape-selective occurs on the outer surface of the zeolite, causing an increase in by-products, which may lower the propylene selectivity.

<Constituent elements and their composition>
The CHA-type zeolite in the present invention is usually composed of a complex oxide of Si and metal M, and preferably a trivalent metal as metal M. Examples of the metal M include aluminum, gallium, iron, boron, titanium, zirconium, tin and the like. Of these, aluminum, gallium and boron are preferably used, more preferably aluminum, and aluminosilicate composed of silicon and aluminum, and further silicoaluminophosphate containing phosphorus are preferable as the CHA-type zeolite of the present invention. Aluminosilicate is more preferable.

Zeolite containing aluminum has a moderately strong acid strength and can be synthesized with a wide range of acid amounts, so that the range of application as a catalyst can be widened. Aluminum is preferable because it has a large Clarke number, is an abundant element, and is inexpensive.
Usually, the above atom source compound of metal M (hereinafter sometimes referred to as “M atom source”) is incorporated into the skeleton after crystallization by adding to the reaction mixture in the hydrothermal synthesis reaction described later together with the Si atom source. .

The ratio of constituent atoms in the CHA-type zeolite is not particularly limited, but the molar ratio of SiO ₂ to M ₂ O ₃ (M is a trivalent metal) contained in the CHA-type zeolite (SiO ₂ / M _When represented by ₂ O ₃ ), it is usually 5 or more, preferably 8 or more, more preferably 10 or more, and still more preferably 15 or more. Moreover, an upper limit is 300 or less normally, Preferably it is 100 or less, More preferably, it is 50 or less, More preferably, it is 30 or less. Note that the molar ratio of SiO ₂ to M ₂ O ₃ in the CHA-type zeolite is assumed to include all Si atom sources in the produced zeolite as SiO ₂ and M atom sources as M ₂ O _3. This is the value obtained. If it is less than the lower limit, deactivation due to coke adhesion tends to be fast, aluminum tends to escape from the skeleton (dealuminization), and the acid strength per acid point tends to be weak. On the other hand, if the amount exceeds the upper limit, the amount of acid is so small that the ethylene conversion rate may decrease.

When the trivalent metal M enters the skeletal structure of the zeolite, there is usually a counter cation for the metal atom in order to compensate the charge balance. Specific counter cation species are not particularly limited, and examples thereof include alkali metal cations such as sodium and potassium, alkaline earth metal cations such as magnesium, calcium and barium, ammonium ions, and protons.

Those in which the counter cation is a proton are hereinafter referred to as “H type”, and the others are collectively referred to as “non-H type”.
The “non-H type” is preferably one having an alkali metal cation, an alkaline earth metal cation, or an ammonium ion as a counter cation in the zeolite skeleton, more preferably an alkali metal cation, an ammonium ion, or more preferably a sodium cation. , Potassium cations, and ammonium ions as counter cations (hereinafter, these may be referred to as “sodium type”, “potassium type”, and “ammonium type”). In general, when zeolite is used as a catalyst, the “non-H type” has a low catalytic function. Since the zeolite obtained by the hydrothermal synthesis reaction described later is usually a “non-H type” zeolite, it is usually preferable to convert it to “H type”.

“H-type” is preferably obtained by a method in which various acids are allowed to act on a “non-H-type” zeolite under conditions capable of maintaining a skeletal structure, or a method in which a product converted into an ammonium-type zeolite is calcined More preferably, all counter cations are protons.
The method for producing a catalyst of the present invention can be applied to either “non-H” or “H” zeolite.

(2) Method for Producing Zeolite Having CHA Type Structure The propylene production catalyst obtained according to the present invention produced a non-H type or H type CHA type zeolite and contained 10 wt% or more and 25 wt% or less of water. The CHA-type zeolite is reacted with a silylating agent in the presence of a hydrocarbon solvent to obtain a silylated zeolite having a CHA-type structure. First, a method for producing a zeolite having a CHA type structure for silylation will be described.

The zeolite having a CHA type structure in the present invention can be usually produced by hydrothermal synthesis using a reaction mixture containing a Si atom source, an M atom source, and an aqueous alkali solution adjusted to a specific composition. In the reaction mixture, various structure-directing agents may be added, and seed crystals may be added. Here, the “reaction mixture” means a raw material mixture for use in hydrothermal synthesis.
The reaction mixture is sealed in a reaction vessel together with seed crystals as necessary, and heated to crystallize the zeolite. In the crystallized zeolite, the alkali source in the reaction mixture is usually a counter cation.

<Raw material>
The Si atom source is not particularly limited. For example, amorphous silica, colloidal silica, silica gel, sodium silicate, amorphous silicate gel, tetraethoxysilane (TEOS), tetramethoxysilane (TMOS), trimethoxyethoxysilane. Etc.
Moreover, only 1 type may be used for Si atom source, and 2 or more types may be mixed and used for it.

The M atom source is not particularly limited, and various metal salts such as hydroxides, oxides, sulfates, nitrates, and hydrochlorides of the trivalent metals, or metal silicate gels are used. For example, when the M atom is an aluminum atom, specific examples include aluminum hydroxide, aluminum sulfate, aluminum nitrate, aluminum chloride, sodium aluminate, amorphous aluminosilicate gel, and the like. As the M atom source, only one kind of the above atom source may be used, or two or more kinds of atom sources may be mixed and used.

Although the alkali source used for aqueous alkali solution is not specifically limited, Usually, a metal is contained (henceforth an alkali origin metal). Examples of the alkali-derived metal usually include alkali metals and alkaline earth metals, and are preferably alkali metals because of their high solubility.
Examples of the alkali metal source include alkali metal hydroxides such as LiOH, NaOH, KOH, and CsOH. Examples of the alkaline earth metal source include alkaline earth metal hydroxides such as Mg (OH) ₂ , Ca (OH) ₂ , Sr (OH) ₂ , and Ba (OH) ₂ .

<Structure directing agent>
In the production of a zeolite having a CHA type structure in the present invention, a hydrothermal synthesis can be performed by adding a structure-directing agent to the reaction mixture as necessary. The structure directing agent is not particularly limited as long as it can promote crystallization of CHA-type zeolite from the reaction mixture. For example, N, N, N-trialkyl-1-adamantanammonium cation, N, N, N A cation derived from an alicyclic amine such as a cation derived from a trialkylbenzylammonium cation, a 3-quinuclidinal, a cation derived from 2-exo-aminonorbornene, an N, N, N-trialkylcyclohexylammonium cation N, N, N-trialkyl-1-adamantanammonium cation and N, N, N-trialkylbenzylammonium cation are preferable in terms of promoting crystallization of high silica zeolite. Preferred as the N, N, N-trialkyl-1-adamantanammonium cation is the N, N, N-trimethyl-1-adamantanammonium cation, and preferred as the N, N, N-trialkylbenzylammonium cation. N, N, N-trimethylbenzylammonium cation. These structure directing agents may be used alone or in combination of two or more.

When a structure directing agent is used, it is advantageous in terms of promoting crystallization. Moreover, the ratio of the silicon atom with respect to an aluminum atom becomes high, and it is preferable at the point which can crystallize the aluminosilicate which the acid resistance and the stability in a hydrothermal synthesis reaction improved.
When a structure directing agent is used, the ratio between the structure directing agent and the Si atom source is not particularly limited, but the molar ratio of the structure directing agent to Si atoms is usually 0.001 or more, preferably 0.01. As mentioned above, More preferably, it is 0.02 or more, and an upper limit is 1.0 or less normally, Preferably it is 0.5 or less, More preferably, it is 0.3 or less. Crystallization is facilitated if the amount of the structure-directing agent is such that the structure-directing agent is contained in four CHA cages having a zeolite structure at a ratio of one.
If it is less than the lower limit, crystallization of CHA-type zeolite may not be promoted. If the upper limit is exceeded, crystallization becomes easy, but the hydrothermal stability and acid resistance of the product may be lowered. When a structure directing agent is not used, it is advantageous in terms of cost or the reduction of the labor of waste liquid treatment after hydrothermal synthesis.

<Seed crystal>
In the production of the CHA-type zeolite in the present invention, hydrothermal synthesis can be performed by adding seed crystals to the reaction mixture as necessary. The seed crystal may be added to the reaction mixture after being dispersed in an appropriate solvent such as water, or may be added without being dispersed.

The seed crystal used in the production of the CHA-type zeolite is not particularly limited as long as it promotes crystallization, but CHA-type zeolite, particularly CHA-type aluminosilicate, is preferable for efficient crystallization.
It is desirable that the seed crystal has a small particle size, and it may be used after pulverization if necessary. The seed crystal has a particle size of usually 0.5 nm or more, preferably 1 nm or more, more preferably 2 nm or more, and is usually 5 μm or less, preferably 3 μm or less, more preferably 1 μm or less. Here, the particle diameter of the seed crystal is the value of the primary particle and the value of the minimum diameter.

The amount of seed crystals added to the reaction mixture is not particularly limited, but the amount of seed crystals added to the Si atom source in the reaction mixture is usually 0.1% by weight or more, preferably 0.5% by weight or more. The amount is preferably 1% by weight, and usually 40% by weight or less, preferably 30% by weight or less, more preferably 25% by weight or less.
If the amount of seed crystal added is less than the lower limit, the number of precursors directed to the CHA-type structure is reduced, so that it is difficult to obtain a CHA-type structure. When the amount of seed crystals added exceeds the upper limit, the proportion of seed crystals contained in the product increases, so that CHA newly produced from the reaction mixture decreases, and the productivity decreases.

<Hydrothermal synthesis conditions>
The reaction vessel used for the hydrothermal synthesis is not particularly limited as long as it can be used for hydrothermal synthesis known per se, and may be a heat and pressure resistant vessel such as an autoclave.
The reaction temperature (heating temperature) in the hydrothermal synthesis is not particularly limited, and is usually 100 ° C. or higher, preferably 120 ° C. or higher, more preferably 150 ° C. or higher, and the upper limit is usually 200 ° C. or lower, preferably 190 ° C. Below, more preferably 180 ° C. or less. The temperature range is suitable for crystallizing the reaction mixture. Below the lower limit, the CHA type aluminosilicate may not crystallize. Moreover, when the upper limit is exceeded, an aluminosilicate having a structure different from that of the CHA type may be generated.

The pressure at the time of crystallization is not particularly limited, and the self-generated pressure generated when the reaction mixture placed in a closed vessel is heated to the above temperature range is sufficient, but if necessary, an inert gas such as nitrogen is added. May be.
Zeolite after hydrothermal synthesis is usually obtained in alkali metal type, alkaline earth metal type, preferably sodium type or potassium type because alkali-derived metal ions contained in the reaction gel exist as the counter cation of the zeolite. It is done.

  After the zeolite is crystallized, it can be converted to the ammonium type by ion exchange of the zeolite using a known method. Specifically, the alkali metal type and alkaline earth metal type zeolites can be converted into ammonium type zeolites using various ammonium salts. By baking this ammonium type, it can be converted to the “H type”.

  In addition, the crystallized zeolite can be loaded with metal on the zeolite by various methods. Examples of the metal source to be supported include copper, iron, cobalt, chromium, platinum and the like. Moreover, these metal sources may use only 1 type, and may mix and use 2 or more types.

(3) Production method of zeolite having silylated CHA type structure The production method of the present invention comprises reacting a zeolite having a CHA type structure containing water in a specific range with a silylating agent in the presence of a hydrocarbon solvent. Is obtained. Hereinafter, the silylation step will be described.
The zeolite having a CHA type structure obtained in the present invention is usually obtained by silylating the outer surface of the zeolite. By silylated the outer surface of the zeolite, the acidic hydroxyl group on the outer surface of the zeolite is coated, and the amount of acid on the outer surface can be reduced. In the present invention, the acidic hydroxyl group or silanolic hydroxyl group in the vicinity of the outer surface pores is silylated, whereby the outer surface pore diameter is reduced, and higher shape selectivity is exhibited than that of ordinary CHA-type zeolite. It is considered a thing.

  In the present invention, when the zeolite is silylated, the zeolite containing water in a specific range is silylated. The moisture contained in the zeolite may be adjusted to a specific range by artificially supplying moisture even if the zeolite originally contains. Usually, zeolite is converted to "non-H type" by calcining the one obtained by hydrothermal synthesis, and further converted to "H type" by calcining after converting to ammonium type if necessary Is used. Therefore, it is usually assumed that the water content of the zeolite before silylation is very low. In this case, before being subjected to silylation, the zeolite is used by supplying moisture so as to contain a specific moisture content and adjusting the moisture content.

  Further, the moisture contained in the zeolite is not limited whether it is present on the surface of the zeolite or in the pores of the zeolite, but it is usually preferable to be present in the pores of the zeolite. This is because the water present in the zeolite pores is considered to play a role of hydrolyzing the substituent on the silyl group that has reacted with the outer surface of the zeolite and to increase the silylation coating efficiency. That is, it is considered that when a substituent on the silyl group is hydrolyzed, a new silanolic hydroxyl group is generated and further reacts with the silylating agent at that site. Further, it is considered that the steric hindrance near the silyl group bonded to the outer surface is alleviated, and the silylating agent access efficiency and reaction efficiency are improved. Therefore, the silylating agent preferably has at least two or more detachable substituents. In addition, since the diffusion of water molecules to the outside of the crystal occurs through the outer surface pores, it is considered that the silylation efficiency in the vicinity of the pores is particularly high and the outer surface pore diameter is thereby reduced.

<Moisture content>
In the production method of the present invention, the zeolite having a CHA type structure to be subjected to silylation treatment contains a predetermined amount of moisture. As described above, usually, after adjusting the zeolite to a predetermined water content, a silylation treatment is performed (hereinafter sometimes referred to as humidity conditioning treatment).
The water content here is expressed in terms of% by weight of the amount of water contained in the zeolite with respect to the dry zeolite weight, and is 10% by weight or more and 25% by weight or less. Preferably it is 12 weight% or more, More preferably, it is 14 weight% or more. Moreover, it is preferably 23% by weight or less, more preferably 20% by weight or less. If the water content of the zeolite is less than the lower limit, the silylated coating efficiency may be reduced, and there may be a case where the outer surface acid sites are not sufficiently covered or the pore diameter is reduced. As a result, the pores are blocked and the catalytic activity tends to decrease.

<Humidity treatment method>
The humidity control method is not particularly limited as long as it can be adjusted to a predetermined moisture content. For example, humidity control can be performed by leaving the zeolite in an atmosphere having an appropriate relative humidity. Moreover, humidity control can also be performed by placing a container containing water in a desiccator and leaving the zeolite in a saturated steam atmosphere. In some cases, humidity control can also be performed under conditions in which the water vapor pressure in the desiccator is adjusted by allowing a container containing a saturated aqueous solution of an inorganic salt such as ammonium chloride or ammonium sulfate to coexist. In addition, humidity can be controlled by circulating a gas having an appropriate water vapor pressure. In addition, in order to perform a more uniform humidity control, the humidity control process may be performed while mixing or stirring the zeolite.

<Silylating agent>
The silylating agent is not particularly limited as long as it is a molecule that can silylate the zeolite surface and cannot silylate the pores of the zeolite. Silicone, chlorosilane, alkoxysilane , Siloxane, silazane and the like can be used. Of these, a preferred silylating agent is alkoxysilane.

  Specific examples of silicone 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 chlorosilane include tetrachlorosilane, trichlorosilane, trichloromethylsilane, dichlorodimethylsilane, chlorotrimethylsilane, trichloroethylsilane, dichlorodiethylsilane, and chlorotriethylsilane.
Specific examples of the alkoxysilane include tetramethoxysilane, tetraethoxysilane and the like; quaternary alkoxysilane, trimethoxymethylsilane, trimethoxyethylsilane, triethoxymethylsilane, triethoxyethylsilane and the like; tertiary alkoxy Secondary alkoxysilanes such as silane, dimethoxydimethylsilane, dimethoxydiethylsilane, diethoxydimethylsilane, diethoxydiethylsilane, etc .; primary alkoxysilanes such as methoxytrimethylsilane, methoxytriethylsilane, ethoxytrimethylsilane, ethoxytriethylsilane, etc. 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 siloxane include hexamethyldisiloxane, hexaethyldisiloxane, pentamethyldisiloxane, tetramethyldisiloxane, and the like, and hexamethyldisiloxane is preferred.
Specific examples of the silazane include hexamethyldisilazane, dipropyltetramethyldisilazane, diphenyltetramethyldisilazane, tetraphenyldimethyldisilazane, and the like, and hexamethyldisilazane is preferable.

<Solvent>
In the production method of the present invention, silylation is carried out in a hydrocarbon solvent. The type of hydrocarbon used in the solvent is not particularly limited, and both aliphatic hydrocarbons and aromatic hydrocarbons can be used. Specific examples of the aliphatic hydrocarbon include pentane, hexane, heptane, octane, nonane, decane, cyclopentane, and cyclohexane. Specific examples of the aromatic hydrocarbon include benzene, toluene, and xylene. Used. Of these, preferred hydrocarbons are hexane, benzene, toluene, and xylene.

<Reaction raw material composition>
The concentration of the silylating agent in the hydrocarbon solvent is not particularly limited, but is usually 0.01% by weight or more, preferably 0.5% by weight or more, more preferably 1% by weight or more. Moreover, it is 80 weight% or less normally, Preferably it is 60 weight% or less, More preferably, it is 40 weight% or less. If the silylating agent concentration is less than the lower limit, the reaction time tends to be longer because the silylation rate is reduced. If the silylating agent concentration exceeds the upper limit, a condensation reaction between the silylating agents in the solution occurs. It tends to be easier.

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. is there. Moreover, it is 5 mol or less normally, Preferably it is 3 mol or less, More preferably, it is 1 mol or less. If the amount of the silylating agent is less than the lower limit, silylation may be insufficient, and the effect of silylation may be reduced.If the amount exceeds the upper limit, the silylating agent may be excessively laminated to block pores. is there. The amount of the silylating agent is expressed by 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 silylated. It will be treated as the number of moles of agent.

  The amount of the solvent for the zeolite 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 zeolite. Moreover, it is usually 100 g or less, preferably 60 g or less, more preferably 20 g or less. When the amount of the solvent with respect to the zeolite is less than the lower limit, stirring of the solvent may be insufficient, and when the amount exceeds the upper limit, the productivity may be lowered.

<Reaction conditions>
The temperature for the silylation treatment depends on the kind of the silylating agent and the solvent, but is not particularly limited, and 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. If the amount is less than the lower limit, the progress of silylation tends to be slow, and if the amount exceeds the upper limit, moisture in the zeolite pores is greatly lost, and the silylation efficiency may be lowered.

The time required to raise the temperature from the addition of the silylating agent to the silylation temperature 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, if the time required for temperature rise is too short, the water discharge rate from the inside of the zeolite pores increases, the hydrolysis and polymerization reaction of the silylating agent in the solution proceeds, and the outer surface of the zeolite The silylation efficiency of may decrease.
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. If the treatment time is too short, sufficient silylation does not occur, and the decrease in the acid amount on the outer surface may be insufficient.

<Silylated zeolite>
The silylated CHA-type zeolite obtained by the present invention can be obtained by silylating the non-H-type or H-type zeolite.
The framework structure and particle diameter of CHA-type zeolite are not greatly changed and are basically the same as before silylation. In the atomic composition, the ratio of Si atoms increases as the silylating agent forms a new bond with the outer surface reaction site of the zeolite.
The total acid amount of the zeolite having a silylated CHA-type structure obtained by the present invention is not particularly limited, but is not greatly changed by the silylation treatment, and is usually 4.8 mmol / g or less, Preferably it is 2.8 mmol / g or less. Moreover, it is 0.15 mmol / g or more normally, Preferably it is 0.30 mmol / g or more. When the upper limit is exceeded, when the silylated zeolite is used as a catalyst for the hydrocarbon conversion reaction, the deactivation due to coke generation becomes faster, the metal easily escapes from the skeleton, and the acid strength per acid point becomes weaker. If the amount is less than the lower limit, the amount of acid is small, and the activity as a catalyst tends to decrease.
The outer surface acid amount of the silylated CHA-type zeolite obtained by the present invention is not particularly limited, but decreases by silylation treatment and is usually 0.6 mmol / g or less, preferably 0.3 mmol / g or less. When the above upper limit is exceeded, when the silylated zeolite is used as a catalyst, a reaction that is not shape-selective occurs on the outer surface of the zeolite and tends to cause an increase in by-products. The fewer the better.

(4) Catalyst for Propylene Production Comprising Silylated CHA Type Zeolite When the zeolite having the CHA type structure obtained in the present invention is used as a catalyst in the reaction, it may be used as it is in the reaction as a catalyst. Inert materials and binders may be granulated and molded, or these may be mixed for use in the reaction. Further, the outer surface acid amount can be reduced with respect to the total acid amount by molding. In addition, when the zeolite obtained in the present invention is used as a catalyst, since the zeolite is usually an active component of the catalyst, the zeolite in the catalyst is sometimes referred to as a “catalytic active component”.
Examples of the substance or binder inert to the reaction include alumina or alumina sol, silica, silica sol, quartz, and a mixture thereof. Examples of the method for reducing the acid amount on the outer surface by molding include a method of bonding the acid sites on the outer surface of the binder and the zeolite.

When a binder having an acid point, such as alumina, is used, the outer surface acid amount and the total acid amount are measured as a total value including the acid amount of the binder as well as the acid amount of the zeolite. . In that case, it is possible to determine the acid amount of the binder by another method and subtract the value to determine the outer surface acid amount and the total acid amount not including the binder acid amount. The method for determining the acid amount of the binder is not particularly limited. For example, in ²⁷ Al-NMR, the total acid amount of the zeolite is determined from the peak intensity of 4-coordinated Al derived from the zeolitic acid point, and determined by the ammonia temperature programmed desorption method. Examples include a method of subtracting from the total value of the total zeolite acid amount and the binder acid amount.

(5) Propylene Production Method Using Propylene Production Catalyst Containing Silylated CHA-Type Zeolite Next, the obtained propylene production catalyst is reacted with ethylene (hereinafter referred to as ethylene conversion reaction). The method for producing propylene will be described (hereinafter referred to as the method for producing propylene in the present invention).

(a) Reaction method <Reaction raw material>
The raw material ethylene 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.
Incidentally, ethanol is easily dehydrated and converted to ethylene by the acid sites present in the zeolite. Therefore, the reaction described in the present invention can be carried out even if ethanol is directly introduced into the reactor as a raw material.

Moreover, when manufacturing propylene by this invention, you may recycle the olefin contained in reactor outlet gas.
The olefin to be recycled is usually ethylene, but other olefins may be recycled. As the raw material olefin, a lower olefin is preferable, and a branched olefin is not preferable because it is difficult to enter the zeolite pores due to its molecular size. The olefin is preferably ethylene or linear butene, and most preferably ethylene.

<Reactor>
In the method for producing propylene of the present invention, it is usually preferable to produce propylene by bringing ethylene into contact with a catalyst in a reactor. Although the form of the reactor to be used is not particularly limited, a continuous fixed bed reactor or a fluidized bed reactor is usually selected. A fluidized bed reactor is preferred.
When packing the above-mentioned catalyst into the fluidized bed reactor, in order to keep the temperature distribution in the catalyst layer small, the particles inactive to the reaction such as quartz sand, alumina, silica, 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.

<Diluent>
In the reactor, in addition to ethylene, helium, argon, nitrogen, carbon monoxide, carbon dioxide, hydrogen, water (steam), paraffins, hydrocarbons such as methane, aromatic compounds, and their A gas inert to the reaction, such as a mixture, can be present, and among these, hydrogen or water (water vapor), preferably hydrogen, preferably coexists.

(B) Reaction conditions <Substrate concentration>
There is no particular restriction on the concentration of ethylene in all feed components fed to the reactor (ie substrate concentration), but usually ethylene is less than 90 mol% in all feed components. Preferably it is 70 mol% or less. Moreover, it is 5 mol% or more normally. When the substrate concentration exceeds the upper limit, the production of aromatic compounds and paraffins becomes remarkable, and the propylene selectivity tends to decrease. If the substrate concentration is less than the lower limit, the reaction rate decreases, so a large amount of catalyst is required, and the reactor tends to be too large.
Therefore, it is preferable to dilute ethylene with the above-mentioned diluent as necessary so as to obtain such a substrate concentration.

<Space velocity>
The space velocity 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 weight of the catalyst is the weight of an inactive component used for granulation / molding of the catalyst or a catalytically active component not containing a binder.

Space velocity, but it is not particularly ^limited, is preferably between 0.01Hr ^-1 ~500Hr -1, more preferably between 0.1 hr ^-1 to 100 Hr ^-1. If the space velocity is too high, the amount of ethylene in the reactor outlet gas increases, which is not preferable because the propylene yield decreases. On the other hand, when the space velocity is too low, undesirable by-products such as paraffins are generated, and the propylene selectivity is lowered, which is not preferable.

<Reaction temperature>
The reaction temperature is not particularly limited as long as ethylene is brought into contact with the catalyst to produce propylene, but is usually 200 ° C or higher, preferably 300 ° C or higher, and usually 700 ° C or lower, preferably 600 ° C or lower. It is. When the reaction temperature is less than the lower limit, the reaction rate is low, a large amount of unreacted raw material tends to remain, and the propylene yield also tends to decrease. On the other hand, if the reaction temperature exceeds the upper limit, the propylene yield may be significantly reduced.

<Reaction pressure>
The reaction pressure is not particularly limited, but is usually 3 MPa (absolute pressure, the same shall apply hereinafter) or less, preferably 1 MPa or less, and more preferably 0.7 MPa or less. Moreover, it is 1 kPa or more normally, Preferably it is 50 kPa or more. When the reaction pressure is less than the lower limit, the reaction rate tends to decrease, and when the reaction pressure exceeds the upper limit, the amount of undesired by-products such as paraffins increases and propylene selectivity tends to decrease.

<Catalyst regeneration>
The catalyst subjected to the reaction can be regenerated and used. Specifically, the catalyst having a reduced ethylene conversion rate can be regenerated using various known catalyst regeneration methods.
The regeneration method is not particularly limited, but specifically, for example, it can be regenerated using air, nitrogen, water vapor, hydrogen, etc., and it is preferable to regenerate using hydrogen (for example, JP-A-2011-2011). 78962).

<Conversion rate>
The conversion rate of ethylene is not particularly limited, but it is usually 20% or more, preferably 40% or more, more preferably 50% or more, and usually 95% or less, preferably 90% or less. It is preferable to carry out.
If this conversion rate is less than the lower limit, there are many unreacted ethylenes and the propylene yield is low, which may not be preferable. On the other hand, if the upper limit is exceeded, the amount of undesired by-products such as paraffins increases, and the propylene selectivity decreases, which may be undesirable.
When the reaction is carried out in a fluidized bed reactor, the catalyst can be operated at a preferred conversion rate by adjusting the residence time of the catalyst in the reactor and the residence time in the regenerator.
The conversion rate is a value calculated by the following formula.
Ethylene conversion (%) = [[Reactor inlet ethylene (mol / Hr) −Reactor outlet ethylene (mol / Hr)] / Reactor inlet ethylene (mol / Hr)] × 100

<Selectivity>
The selectivity in this specification is a value calculated by the following equations. In the following formulas, “derived carbon flow rate (mol / Hr)” of propylene, butene, C ₅ +, paraffin or aromatic hydrocarbon means the molar flow rate of carbon atoms constituting each hydrocarbon. . Paraffin is the sum of paraffins having 1 to 4 carbon atoms, aromatic compounds are the sum of benzene, toluene, and xylene, and C ₅ + is the sum of C ₅ or more hydrocarbons excluding the aromatic compounds.

Propylene selectivity (%) = [reactor outlet propylene-derived carbon molar flow rate (mol / Hr) / [reactor outlet total carbon molar flow rate (mol / Hr) −reactor outlet ethylene-derived carbon molar flow rate (mol / Hr)] ] × 100
Butene selectivity (%) = [reactor outlet butene-derived carbon molar flow rate (mol / Hr) / [
Reactor outlet total carbon molar flow rate (mol / Hr) −reactor outlet ethylene-derived carbon molar flow rate (mol / Hr)]] × 100
C ₅ + selectivity (%) = [reactor outlet C ₅ + derived carbon molar flow rate (mol / Hr) / [
Reactor outlet total carbon molar flow rate (mol / Hr) −reactor outlet ethylene-derived carbon molar flow rate (mol / Hr)]] × 100
Paraffin selectivity (%) = [reactor outlet paraffin-derived carbon molar flow rate (mol / Hr) / [reactor outlet total carbon molar flow rate (mol / Hr) −reactor outlet ethylene-derived carbon molar flow rate (mol / Hr)] ] × 100
Aromatic compound selectivity (%) = [reactor outlet aromatic compound-derived carbon molar flow rate (mol / Hr) / [reactor outlet total carbon molar flow rate (mol / Hr) −reactor outlet ethylene-derived carbon molar flow rate (mol) / Hr)]] × 100
In addition, the yield in this specification is calculated | required by the product of the said ethylene conversion rate and the selectivity of each produced | generated component, and a propylene yield is a value specifically represented by the following formula.
Propylene yield (%) = ethylene conversion (%) × propylene selectivity (%) / 100

(C) Reaction product As the reactor outlet gas (reactor effluent), a mixed gas containing reaction product propylene, unreacted ethylene, by-products and a diluent is obtained. The propylene concentration in the mixed gas is usually 1% by weight or more, preferably 2% by weight or more, and usually 95% by weight or less, preferably 80% by weight 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 4 or more carbon atoms and paraffins.

Polypropylene can be produced by polymerizing propylene obtained by the method for producing propylene in the present invention. The method of polymerization is not particularly limited, but the obtained propylene can be directly used as a raw material for the polymerization system. It can also be used as a raw material for other propylene derivatives. For example, acrylonitrile can be produced by ammonia oxidation, acrolein, acrylic acid and acrylic acid ester can be produced by selective oxidation, normal butyl alcohol can be produced by oxo reaction, and propylene oxide and propylene glycol can be produced by selective oxidation. In addition, acetone can be produced by Wacker reaction, and methyl isobutyl ketone can be produced from acetone. Acetone cyanohydrin can also be produced from acetone, which is finally converted to methyl methacrylate. Isopropyl alcohol can also be produced by propylene hydration. Phenol, bisphenol A, or polycarbonate resin can be produced from a cumene produced by reacting propylene with benzene.

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.
<Measurement method of pore distribution>
The pore distribution was measured using NOVA1200 manufactured by Yuasa Ionics. About 10 mg of zeolite was pretreated at 200 ° C. for 1 hour under vacuum conditions to desorb and remove the adsorbate, and then an isotherm was measured using nitrogen gas as the adsorbed gas. The adsorption isotherm was obtained by measuring the equilibrium adsorption amount at the time of adsorption and desorption with the relative pressure at the liquid nitrogen temperature. The relative pressure region during the adsorption amount measurement is 0.02 to 0.99, and the relative pressure is changed in increments of 0.02 to 0.1. In a region where the change in adsorption amount is large, the measurement is performed with a small change in relative pressure.
The cumulative pore volume was calculated from the obtained isotherm by the BJH method. The BJH method is one of measurement methods for obtaining the pore distribution from the adsorption isotherm.

(Catalyst Preparation Example 1)
25% by weight of N, N, N-trimethyl-1-adamantanammonium hydroxide aqueous solution (N, N, N-trimethyl-1-adamantammonium hydroxide) 2.96 kg and sodium hydroxide 0.280 kg in order, After dissolving in 25.5 kg and then adding 0.448 kg of aluminum hydroxide (50-57 wt% in terms of aluminum oxide) and stirring, 2.11 kg of fumed silica as a silica source was added and sufficiently stirred. Further, 2% by weight of CHA-type zeolite was added as a seed crystal to the weight of the added fumed silica and further stirred. Next, this gel was charged into a 50 l autoclave, and hydrothermal synthesis was performed at 160 ° C. for 48 hours while stirring at 100 rpm under a self-pressure. The product was filtered, washed with water and dried.
The dried catalyst was calcined at 580 ° C. for 6 hours under air flow to obtain sodium-type zeolite. The zeolite was ion-exchanged twice with a 1M aqueous ammonium nitrate solution at 80 ° C. for 1 hour, dried at 100 ° C., and then calcined at 500 ° C. for 6 hours under air flow to obtain proton type zeolite A.
The zeolite obtained above was a CHA type H type zeolite, and the SiO ₂ / Al ₂ O ₃ ratio was 15 (molar ratio). Moreover, the primary particle diameter of zeolite is about 70-100 nm by the measurement of the scanning electron microscope, and the cumulative pore volume in the range of the pore diameter of 100-200 mm is 46 × 10 ⁻³ from the measurement of the pore distribution. ml / g.

(Catalyst preparation example 2)
A solution of 3.91 g of sodium hydroxide and 47.3 g of 25% by weight aqueous solution of N, N, N-trimethyl-1-adamantanammonium hydroxide (N, N, N-trimethyl-1-adamantammonium hydroxide) in water 90 Next, 4.26 g of aluminum hydroxide (50 to 57% by weight in terms of aluminum oxide) was added and mixed, and then colloidal silica SI-30 (SiO ₂ 30% by weight, Na 0.3 110% by weight (manufactured by JGC Catalysts & Chemicals) was added and sufficiently stirred. Further, 2% by weight of CHA-type zeolite was added as a seed crystal to the weight of the added SiO ₂ and further stirred. Next, this gel was charged into a 1000 ml autoclave, and hydrothermal synthesis was performed at 160 ° C. for 42 hours while stirring at 150 rpm under an autogenous pressure. The product was filtered, washed with water and dried.
The dried catalyst was calcined at 580 ° C. for 6 hours under air flow to obtain sodium-type zeolite. The zeolite was ion-exchanged twice at 80 ° C. for 1 hour with a 1M ammonium nitrate aqueous solution, dried at 100 ° C., and then calcined at 500 ° C. for 6 hours under air flow to obtain proton type zeolite B.
The zeolite obtained above was a CHA type H type zeolite, and the SiO ₂ / Al ₂ O ₃ ratio was 24 (molar ratio). Moreover, the primary particle diameter of the zeolite was about 50 to 80 nm as measured by a scanning electron microscope, and the cumulative pore volume in the range of the pore diameter of 100 to 200 mm was 51 × 10 ⁻³ from the measurement of the pore distribution. ml / g.

Example 1
The zeolite A 0.50 g obtained in Preparation Example 1 was placed in a porcelain dish and opened in the atmosphere, so that the moisture content in the zeolite was adjusted to 12.6% by weight. On the other hand, 5.0 ml (4.3 g) of toluene as a solvent and 1.25 ml (1.16 g) of tetraethoxysilane as a silylating agent were added, and heat treatment was performed at 100 ° C. for 6 hours while stirring. After the treatment, the solid-liquid was separated by filtration, and the resulting zeolite was dried at 100 ° C. to obtain a silylated catalyst.
For the reaction, a normal pressure fixed bed flow reactor was used, and a mixture of 100 mg of the catalyst and 400 mg of quartz sand was packed in a quartz reaction tube having an inner diameter of 6 mm. Ethylene and nitrogen were supplied to the reactor so that the space velocity of ethylene was 0.36Hr ⁻¹ and 30% by volume of ethylene and 70% by volume of nitrogen, and a synthesis reaction of propylene was performed at 350 ° C. and 0.1 MPa. . The product was analyzed by gas chromatography 125 minutes and 200 minutes after the start of the reaction. The reaction results are shown in Table 1.

(Example 2)
A catalyst was obtained by silylation in the same manner as in Example 1 except that the amount of water contained in the zeolite was changed to 16.6% by weight. This catalyst was charged into the same reactor as in Example 1, and a synthesis reaction of propylene was carried out under the same reaction conditions. The reaction results are shown in Table 1.

(Example 3)
A catalyst was obtained by silylation in the same manner as in Example 1 except that the amount of water contained in the zeolite was 19.0% by weight. This catalyst was charged into the same reactor as in Example 1, and a synthesis reaction of propylene was carried out under the same reaction conditions. The reaction results are shown in Table 1.
Example 4
A catalyst was obtained by silylation in the same manner as in Example 1 except that the amount of water contained in the zeolite was 22.5% by weight. This catalyst was charged into the same reactor as in Example 1, and a synthesis reaction of propylene was carried out under the same reaction conditions. The reaction results are shown in Table 1.

(Comparative Example 1)
A catalyst was obtained by silylation in the same manner as in Example 1 except that the amount of water contained in the zeolite was 2.7% by weight. This catalyst was charged into the same reactor as in Example 1, and a synthesis reaction of propylene was carried out under the same reaction conditions. The reaction results are shown in Table 1.

(Example 5)
A catalyst was obtained by silylating in the same manner as in Example 1 except that zeolite B obtained in Preparation Example 2 was used and the amount of water contained in the zeolite was changed to 10.6% by weight. This catalyst was charged into the same reactor as in Example 1, and a synthesis reaction of propylene was carried out under the same reaction conditions. The reaction results are shown in Table 2.
(Example 6)
A catalyst was obtained by silylation in the same manner as in Example 5 except that the amount of water contained in the zeolite was changed to 14.6% by weight. This catalyst was charged into the same reactor as in Example 1, and a synthesis reaction of propylene was carried out under the same reaction conditions. The reaction results are shown in Table 2.
(Example 7)
A catalyst was obtained by silylation in the same manner as in Example 5 except that the amount of water contained in the zeolite was changed to 16.7% by weight. This catalyst was charged into the same reactor as in Example 1, and a synthesis reaction of propylene was carried out under the same reaction conditions. The reaction results are shown in Table 2.
(Example 8)
A catalyst was obtained by silylation in the same manner as in Example 5 except that the amount of water contained in the zeolite was 21.5% by weight. This catalyst was charged into the same reactor as in Example 1, and a synthesis reaction of propylene was carried out under the same reaction conditions. The reaction results are shown in Table 2.
(Comparative Example 2)
A catalyst was obtained by silylation in the same manner as in Example 5 except that the amount of water contained in the zeolite was 2.9% by weight. This catalyst was charged into the same reactor as in Example 1, and a synthesis reaction of propylene was carried out under the same reaction conditions. The reaction results are shown in Table 2.

(Comparative Example 3)
A catalyst was obtained by silylation in the same manner as in Example 5 except that the amount of water contained in the zeolite was 7.3% by weight. This catalyst was charged into the same reactor as in Example 1, and a synthesis reaction of propylene was carried out under the same reaction conditions. The reaction results are shown in Table 2.

In Examples 1 to 4, propylene is produced by contacting ethylene with a catalyst obtained by silylation treatment of a CHA-type zeolite (SiO ₂ / Al ₂ O ₃ ratio is 15) whose water content is adjusted to 10 to 25% by weight. When the reaction was carried out, the by-product of the C5 or higher component was significantly suppressed, and propylene was obtained with high selectivity.
The selectivity for C5 and higher components was approximately 1% or less, and in Examples 3 and 4 having a high water content, the selectivity decreased to less than 0.05%. This is because, in the silylation treatment, when the water in the zeolite diffuses from the outer surface pores into the solvent, the silylating agent alkoxy group that has reacted with the zeolite reaction site is efficiently hydrolyzed, thereby producing a spatial steric structure. This is considered to be because the obstacle was alleviated and the silylated coating efficiency of the acid points on the outer surface was improved. Furthermore, as the water content increases, the silylation reaction on the outer surface of the zeolite, the subsequent hydrolysis of the alkoxy group, and the further silylation reaction are repeated, so that the outer surface pore diameter is reduced. This is thought to be due to the suppression of the discharge of the C5 or higher component, which is a large amount of hydrocarbon, from the pores.

  In a reaction in which ethylene is brought into contact with CHA-type zeolite to produce propylene, ethylene diffuses from the outer surface pores of the CHA-type zeolite into the crystal, ethylene oligomerization proceeds, and further propylene is produced by decomposition of the oligomer. Then, it is presumed to be discharged out of the crystal from the outer surface pores. Although it is considered that hydrocarbons of C5 or higher can be generated by the decomposition of the oligomer, it is considered that C5 or higher hydrocarbons generated in the crystal are difficult to be discharged because the pore diameter of the CHA-type zeolite is small. In addition to the effect of covering the acid sites on the outer surface by silylation, the pore diameter of the CHA-type zeolite is considered to be smaller by adjusting the water content of the zeolite by the production method of the present invention. The produced C5 or higher hydrocarbons are less likely to be discharged, and it is considered that propylene is obtained with higher selectivity.

In Comparative Examples 1 and 2, the selectivity of C5 and higher components and the aromatic selectivity were high, and the propylene selectivity was low. This is presumably because the water content of the zeolite was insufficient, so that the outer surface acid sites could not be sufficiently covered with the silylating agent.
Moreover, in Examples 5-8, by silylating a CHA-type zeolite (SiO ₂ / Al ₂ O ₃ ratio is 24), as in Examples 1 to 4, Comparative Example 3 having a water content of less than 10% Compared to 4, a higher propylene selectivity was obtained, and the selectivity for components of C5 or higher was approximately 1% or lower. The silylation treatment method of the CHA-type zeolite containing water in a specific range of the present invention is not limited to a specific SiO ₂ / Al ₂ O ₃ ratio, but is applied to zeolites having a wide range of SiO ₂ / Al ₂ O ₃ ratio. It is thought that it can be applied to.

According to the present invention, there is provided a method for inexpensively producing a catalyst for producing propylene containing a zeolite having a silylated CHA type structure. In addition, by producing propylene from ethylene using the catalyst for producing propylene obtained by this method, it is possible to inhibit the by-production of the C5 or higher component and efficiently produce propylene.

Claims (6)

  A method for producing a catalyst for propylene production comprising a silylation step of silylating a zeolite having a CHA-type structure, wherein the CHA has a water content of 10 wt% to 25 wt% in the presence of a hydrocarbon solvent in the silylation. A method for producing a catalyst for producing propylene, comprising reacting a zeolite having a mold structure with a silylating agent. _{2. The} method for producing a catalyst for propylene production according to claim 1, wherein the zeolite having the CHA-type structure has a SiO ₂ / Al ₂ O ₃ molar ratio of 5 or more and 300 or less.   The method for producing a catalyst for producing propylene according to claim 1 or 2, wherein the hydrocarbon solvent is any one of hexane, benzene, toluene, and xylene.   The method for producing a catalyst for propylene production according to any one of claims 1 to 3, wherein the silylating agent is any one of silicone, chlorosilane, alkoxysilane, siloxane, and silazane.   The method for producing a catalyst for propylene production according to any one of claims 1 to 4, wherein the silylating agent is a silicon compound having at least two or more alkoxy groups in the molecule.   A method for producing propylene, wherein propylene is produced by bringing ethylene into contact with the catalyst for producing propylene obtained by the method according to any one of claims 1 to 5.