JP2013063865A - Method for producing silylated h-type zeolite having cha-type structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simple production method in the production of a silylated H-type zeolite required to pass through a complicated production step.SOLUTION: The method for producing the silylated H-type zeolite having CHA-type structure is characterized by reacting a non-H-type zeolite having the CHA structure with a silylating agent in the presence of an acidic aqueous solution. Specifically, a non-H-type zeolite obtained by hydrothermal synthesis is subjected to silylation treatment using a concentration-adjusted acid-containing aqueous solution as a reaction solvent to thereby obtain the objective silylated H-type zeolite without collapsing the structure.

Description

  The present invention relates to a method for producing an H-type 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 proposes that propylene can be obtained with high selectivity by using silylated CHA-type zeolite as a catalyst and bringing ethylene into contact with the catalyst. However, there are the following problems in silylation of zeolite.
When producing zeolite, in a hydrothermal synthesis reaction generally performed, an aqueous alkali solution (hereinafter sometimes simply referred to as alkali) is usually used to dissolve the raw material. Therefore, after the hydrothermal synthesis reaction, the obtained product is calcined, and when the zeolite is obtained, the zeolite is a metal derived from an alkaline aqueous solution (for example, an alkali metal or an alkaline earth metal), and a counter cation at the T site. Have. For example, when an aluminosilicate is produced, when an alkali metal (for example, an aqueous sodium hydroxide solution) is used as an alkali to dissolve the raw silicon atom source, the aluminum atoms in the resulting aluminosilicate are: The alkali metal derived from the alkali used as a counter cation (hereinafter sometimes referred to as an alkali metal type zeolite).

In order to silylate the alkali metal type zeolite and use it as an acid catalyst, it is necessary to convert the alkali metal of the counter cation to protons by performing ion exchange before performing the silylation treatment.
As a method of converting the counter cation from an alkali metal to a proton and converting it to an H type (sometimes referred to as a proton type), a method in which an acid is allowed to act is assumed.

As a method for allowing an acid to act on zeolite, Patent Document 2 treats with a solution containing a nitric acid aqueous solution as a treatment method for filling defects in the crystal lattice of the zeolite. Moreover, in patent document 3, in order to expand the interlayer distance of a zeolite, it processes with the solution containing nitric acid aqueous solution.
However, in general, when an acid is allowed to act on zeolite, metal such as aluminum entering the T site is detached, and depending on the degree, the structure may be collapsed as a result. When metal desorption or structural collapse occurs, usually the function of the zeolite, for example, the catalyst performance and the adsorption characteristics deteriorate. For this reason, it is not usual to perform ion exchange with the action of an acid. Also in the examples of Patent Documents 2 and 3, there is a possibility that aluminum is desorbed from the skeleton due to the presence of an acid (hereinafter sometimes referred to as de-Al). In any case, since the silylation treatment is performed in a state of including the structure-directing agent, the structure is kept stable, so that the structure is not collapsed by the acid treatment.

When zeolite does not include a structure-directing agent, metals such as aluminum may be desorbed from the zeolite skeleton, resulting in a decrease in structural regularity or structural collapse. In the pattern obtained by XRD measurement by treating with CHA-type zeolite also with an acid, a decrease in peak intensity is observed, and it is considered that the structural regularity is reduced (see Comparative Examples 2 and 3).

  Therefore, the ion exchange to the H type is usually performed by first exchanging with an ammonium salt and once converting it to the ammonium type, and then baking it to remove ammonium ions. There has been a demand for a method of directly producing silylated H-type zeolite from non-H-type zeolite such as metal type.

International Publication No. 2010/128664 JP 2008-063195 A JP 2008-162846 A

  An object of the present invention is to provide a production method in which silylated H-type zeolite can be directly silylated from a non-H-type zeolite and the zeolite can be obtained structurally stably.

As a result of intensive studies, the inventor conducted silylation treatment on non-H-type zeolite obtained by hydrothermal synthesis using an aqueous solution containing an acid as a reaction solvent. A silylated H-type zeolite was obtained without causing collapse. Then, when propylene was produced by bringing ethylene into contact with the obtained zeolite, it was found that the propylene selectivity was increased and the same result as that obtained when silylated from the H-type state was used was obtained.

That is, the gist of the present invention is as follows.
(1) A method for producing a H-type zeolite having a silylated CHA-type structure, characterized by reacting a non-H-type zeolite having a CHA-type structure with a silylating agent in the presence of an acidic aqueous solution. A method for producing an H-type zeolite having a silylated CHA-type structure.
(2) In the pore diameter distribution obtained by the BJH method from the nitrogen adsorption isotherm of the non-H zeolite, the total pore volume in the range of pore diameters of 100 to 200 mm is 10 × 10 ⁻³ ml / g or more. A method for producing an H-type zeolite having a silylated CHA-type structure as described in (1) above.

(3) The silyl according to (1) or (2) above, wherein the non-H-type zeolite is substituted with any of alkali metal ions, alkaline earth metal ions, and ammonium ions For producing an H-type zeolite having a structured CHA-type structure.
(4) The method for producing an H-type zeolite having a silylated CHA-type structure according to any one of (1) to (3), wherein the non-H-type zeolite is an aluminosilicate.

(5) The method for producing an H-type zeolite having a silylated CHA-type structure according to any one of (1) to (4), wherein the acid concentration in the acidic aqueous solution is 0.01 M or more and 5 M or less. .
(6) The method for producing an H-type zeolite having a silylated CHA-type structure according to any one of (1) to (5), wherein the acidic aqueous solution is sulfuric acid.
(7) The SiO ₂ / M ₂ O ₃ ratio (M is a trivalent metal) of the non-H zeolite is 5 or more and 50 or less, according to any one of (1) to (6) above A method for producing an H-type zeolite having a silylated CHA-type structure.

(8) Silylated H obtained by the production method according to any one of (1) to (7) above
A method for producing propylene, characterized in that propylene is produced using ethylene zeolite as a raw material using a zeolite of a catalyst type as a catalyst.

  According to the present invention, when producing a H-type zeolite having a silylated CHA type structure, the zeolite can be produced directly and structurally stably from the hydrothermally synthesized zeolite (non-H type zeolite). This method eliminates the complexity of the manufacturing process and eliminates the need for a baking process. This makes it possible to significantly reduce the energy cost during manufacturing, in addition to greatly shortening the manufacturing process.

It is the XRD pattern (FIG. 1 (a)) of the zeolite F used in the comparative example 3, and the XRD pattern (FIG. 1 (b)) of the zeolite G obtained in the comparative example 3. It is an XRD pattern (FIG. 2 (a)) of zeolite D used in Reference Example 1, and an XRD pattern (FIG. 2 (b)) of zeolite H obtained in Reference Example 1.

Below, the typical aspect for implementing this invention is demonstrated concretely, However, This invention is not limited to the following forms, unless the summary is exceeded.
The method for producing a H-type zeolite having a silylated CHA-type structure according to the present invention is characterized by reacting a non-H-type zeolite having a CHA-type structure with a silylating agent in the presence of an acidic aqueous solution.

Hereinafter, the components in the present invention will be described.
(1) Zeolite having a CHA type structure First, the physicochemical properties of a zeolite having a CHA type structure produced by the method of the present invention (hereinafter sometimes referred to as “CHA type zeolite”) will be described.
In the present invention, the CHA structure is a code that defines the structure of the zeolite defined by the International Zeolite Association (hereinafter may be abbreviated as “IZA”) and indicates the CHA structure. This is a zeolite having a crystal structure equivalent to that of naturally occurring chabazite.

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

  The CHA-type zeolite in the present invention is usually composed of a complex oxide of Si and a trivalent 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 preferred.

A material containing aluminum has a moderately strong acid strength and can be synthesized with a wide range of acid amounts, and the applicable range is widened when used as a catalyst. 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 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.

The molar ratio of SiO ₂ to M ₂ O ₃ in the CHA-type zeolite is assumed that all Si atom sources in the produced zeolite are included as SiO _{2 and} all M atom sources are included as M ₂ O _3. This is the value to be obtained.
This molar ratio is determined by the ratio of the Si atom source and the M atom source in the reaction mixture in hydrothermal synthesis described later. Those with SiO ₂ / M ₂ O ₃ molar ratio of the, in this specification, sometimes referred to high-silica zeolite. High silica zeolite has high acid resistance and high hydrothermal stability.

Normally, when zeolite is exposed to acidic conditions or hydrothermal conditions, the metal constituting the skeleton may be desorbed from the zeolite skeleton, and the skeleton may be collapsed when there are many desorbed metals. However, in high silica zeolite with a small amount of metal atoms in the skeleton, metal atoms are difficult to desorb, and even when desorbed, skeleton collapse is difficult to occur.
In the present invention, since silylation is performed in an acidic solvent, there is a possibility that the skeleton collapses when the amount of metal exceeds the upper limit in this respect.

Moreover, since high silica zeolite becomes hydrophobic, when used as an adsorbent, adsorption of hydrophobic molecules such as hydrocarbons easily occurs. In addition, when used as a catalyst, the hydrophobic molecules easily enter the pores, so that the reaction of the hydrophobic molecules easily proceeds.
When the trivalent metal M enters the framework structure of the zeolite, a counter cation for the metal atom is usually present in the framework of the zeolite in order to compensate the charge balance. Specific metal atom counter cation species are not particularly limited, but include alkali metal cations such as sodium and potassium, alkaline earth metal cations such as magnesium, calcium and barium, ammonium ions, or protons. Etc.
Those in which the counter cation is a proton are hereinafter referred to as “H type”, and others are collectively referred to as “non-H type”.

The “H type” is preferably one in which an acid is allowed to act at an amount equal to or more than the equivalent of the cation site of the zeolite in the silylation described later, and more preferably, all the counter cations are protons.
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”.)
A “non-H” zeolite is usually obtained by the hydrothermal reaction described below. In the present invention, a “non-H-type” zeolite is silylated to obtain a silylated “H-type” zeolite.

The particle size of the CHA-type zeolite in the present invention is not particularly limited, but the total pore volume in the range of 100 to 200 mm of the pore size distribution obtained by the BJH method by the measurement method described below is 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 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 or adsorbent, it is considered that the substrate does not sufficiently enter the inside of the pores, and the utilization rate of zeolite is reduced. When reacted, the activity per weight decreases. Moreover, since the outer surface area per weight is small, the silylation may proceed excessively, possibly blocking the pores. When the upper limit is exceeded, the particle size is small, and it is considered that separation of the zeolite after silylation from the aqueous solution becomes difficult.
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.

<Silylated zeolite>
The silylated H-type CHA-type zeolite obtained by the present invention is obtained by silylating the non-H-type zeolite.
There is no change in the framework structure and particle diameter of the CHA-type zeolite, which is basically the same as before silylation.

The outer surface acid amount of the H-type zeolite having a silylated CHA-type structure obtained in the present invention is not particularly limited, but is usually 0.6 mmol / g or less, preferably 0.3 mmol / g. It is as follows. When 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 catalyst, and there is a tendency to cause an increase in by-products.
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.
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 hydrocarbon conversion reaction, deactivation due to coke adhesion tends to be accelerated, metal tends to escape from the skeleton, and acid strength per acid point tends to be weak. If the amount is less than the lower limit, the activity as a catalyst tends to decrease because the amount of acid is small.

(2) Method for Producing CHA-Type Zeolite The method for producing a zeolite of the present invention produces non-H-type zeolite and silylates the non-H-type zeolite in the presence of an acidic aqueous solution to obtain H-type zeolite. First, a method for producing non-H zeolite will be described.

<Method for producing non-H zeolite>
The non-H-type 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 alkaline aqueous solution adjusted to a specific composition. it can. In the reaction mixture, various structure-directing agents may be added,
A seed crystal 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 usually becomes a counter cation and becomes a non-H type zeolite. When a structure directing agent is added, the structure directing agent may partially exist as a counter cation.
The Si atom source is not particularly limited, and examples thereof include amorphous silica, colloidal silica, silica gel, sodium silicate, amorphous aluminum silicate gel, tetraethoxysilane (TEOS), and tetramethoxysilane. Can be mentioned. Moreover, only 1 type may be used for Si element 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 oxide, 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 N, N, N-trialkyl-1-adamantanammonium cation is N, N, N-trimethyl-1-adamantanammonium cation, and preferred N, N, N-trialkylbenzylammonium cation is N , N, N-benzyltrimethylammonium 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 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.
On the other hand, when a structure directing agent is not used, it is advantageous in terms of cost and 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 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 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 amount of seed crystals added to the reaction mixture is not particularly limited, but the amount of seed crystals added to the Si element source in the reaction mixture is usually 0.1 wt% or more, preferably 0.5 wt% or more, more Preferably it is 1 weight% or more, and is 40 weight% or less normally, Preferably it is 30 weight% or less, More preferably, it is 25 weight% or less.

  If the amount of seed crystal added is less than the lower limit, the number of precursors directed to the CHA structure will decrease, making it difficult to obtain the CHA 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, resulting in low productivity.

<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 above temperature range is suitable for crystallizing the reaction mixture. When the reaction temperature is too low, the CHA type aluminosilicate may not crystallize. Moreover, when reaction temperature is too high, the type of aluminosilicate different from CHA type may be produced | 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.

Further, after the zeolite is crystallized, the metal can be supported 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.

<Silylation>
The H-type zeolite having a CHA-type structure obtained in the present invention can be obtained by reacting a non-H-type zeolite having a CHA-type structure with a silylating agent in the presence of an acidic aqueous solution to carry out silylation. Hereinafter, the silylation step will be described.
The CHA-type zeolite obtained in the present invention is usually obtained by silylating the outer surface of the zeolite. By silylating the outer surface of the zeolite, the acid amount on the outer surface of the zeolite can be reduced. In the present invention, ion exchange from non-H type to H type occurs at the same time.

  In the silylation in an acidic aqueous solution in the present invention, the above counter cation is partially or mostly ion-exchanged with protons during silylation. Since it is ion-exchanged into the proton type, it can be used as an acid catalyst after the silylation treatment without performing ion exchange into the proton type.

  The silylating agent is not particularly limited, but specific examples of the alkoxysilane include quaternary alkoxysilanes such as tetramethoxysilane and tetraethoxysilane; and 3 such as trimethoxymethylsilane and triethoxymethylsilane. Grade alkoxysilanes; secondary alkoxysilanes such as dimethoxydimethylsilane and diethoxydimethylsilane; primary alkoxysilanes such as methoxytrimethylsilane and ethoxytrimethylsilane; and the like. Specific examples of chlorosilane include tetrachlorosilane, dimethyldichlorosilane, and trimethylchlorosilane. Of these, tetraethoxysilane is preferable for alkoxysilane and tetrachlorosilane is preferable for chlorosilane from the viewpoint of stacking silylated layers. When a single silylated layer is desired, methoxytrimethylsilane is used for alkoxysilane, and trimethylchlorosilane is used for chlorosilane.

  In the production method of the present invention, silylation is carried out in 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 or the like can be used. Of these, sulfuric acid is preferred for inorganic acids, acetic acid for carboxylic acids, and oxalic acid for dicarboxylic acids.

  The acid concentration in the acidic aqueous solution is not particularly limited, but is usually 0.01M or more, preferably 0.05M or more, more preferably 0.1M or more, and usually 5M or less, preferably Is 2M or less, more preferably 1M or less. When the acid concentration is less than the lower limit, the progress of the silylation reaction is slowed down, so that the treatment time becomes long and the ion exchange may not proceed sufficiently. When the acid concentration exceeds the above upper limit, the metal forming the skeleton is easily removed, and in some cases, the structure may collapse.

  The concentration of the silylating agent in the acidic aqueous solution is not particularly limited, but is usually 0.01% by weight or more, preferably 0.3% by weight or more, more preferably 0.5% by weight or more. is there. Moreover, it is 25 weight% or less normally, Preferably it is 20 weight% or less, More preferably, it is 10 weight% or less. When the concentration of the silylating agent is less than the lower limit, the progress of silylation is slowed down, so that the treatment time may be longer. When the concentration is higher than the upper limit, condensation between the silylating agents tends to occur.

The amount of the silylating agent with respect to the zeolite is not particularly limited, but is usually 0.001 mol or more, preferably 0.005 mol or more, more preferably 0.01 mol or more with respect to 1 mol of the zeolite. Moreover, it is 0.3 mol or less normally, Preferably it is 0.2 mol or less, More preferably, it is 0.1 mol or less. When the amount of the silylating agent is less than the lower limit, silylation is not sufficient, and the effect of silylation may be reduced. When the amount exceeds the upper limit, the silylating agent may be stacked to block the pores.

  The amount of the acidic aqueous solution with respect to the zeolite is not particularly limited, but is usually 3 g or more, preferably 5 g or more, more preferably 10 g or more, and usually 100 g or less in total amount of the acidic aqueous solution with respect to 1 g of zeolite. , Preferably 80 g or less, more preferably 50 g or less. If the total amount of the acidic aqueous solution relative to zeolite is less than the lower limit, the solution tends to be difficult to stir, whereas if the upper limit is exceeded, productivity may be lowered.

  Although the silylation temperature is not particularly limited, it is usually carried out at room temperature to 100 ° C. at normal pressure, and can be carried out at 100 ° C. or higher in a pressure resistant vessel to further increase the silylation temperature. . Preferably it is 60 degreeC or more, More preferably, it is 80 degreeC or more, More preferably, it is 90 degreeC or more. Moreover, it is 200 degrees C or less normally, Preferably it is 180 degrees C or less, More preferably, it is 150 degrees C or less, More preferably, it is 120 degrees C or less. When the temperature is less than the lower limit, the progress of silylation is slow, and the progress of ion exchange to H-type is also slow. On the other hand, if the temperature exceeds the upper limit, defects may be generated in the zeolite framework and the metal in the framework may be easily removed.

The reaction pressure during the silylation reaction is not particularly limited, but is usually from atmospheric pressure to 0.9 MPa. Preferably, it is 0.05 MPa or more, more preferably 0.1 MPa or more, and the upper limit is preferably 0.7 MPa or less, more preferably 0.5 MPa or less. If the pressure is less than the lower limit, silylation proceeds slowly and ion exchange also tends to progress slowly. On the other hand, if the pressure exceeds the upper limit, defects may be generated in the zeolite framework or the metal in the framework tends to escape. The pressure may be adjusted by changing the vapor pressure of the aqueous solution by adjusting the temperature, or by applying gas from the outside.

(3) Catalyst using H-type zeolite having CHA type When the H-type zeolite having a CHA type structure obtained in the present invention is used as a catalyst in the reaction, it may be used as it is as a catalyst or in the reaction. Inert materials and binders may be granulated and molded, or these may be mixed for use in the reaction. The outer surface acid amount can be decreased 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. As a method for reducing the acid amount by molding, for example, a method of bonding the acid sites on the surface of the binder and the zeolite can be mentioned.

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.

(4) Propylene production method using non-H-type zeolite having CHA type structure <Propylene production method using the obtained catalyst>
Next, a method for producing propylene by reacting the obtained silylated H-type zeolite with a catalyst by contacting ethylene with the catalyst (hereinafter sometimes referred to as ethylene conversion reaction) will be described. (Hereinafter referred to as a method for producing propylene in the present invention.)

(A) Reaction method
<Reaction raw materials>
The raw material ethylene is not particularly limited. For example, dehydrogenation of ethylene and ethane obtained by conducting Fischer-Tropsch synthesis using ethylene produced from a petroleum source by catalytic cracking or steam cracking, etc., and hydrogen / CO mixed gas obtained by gasification of coal Or obtained by oxidative dehydrogenation Ethylene obtained by metathesis reaction and homologation reaction of propylene, ethylene obtained by MTO (Methanol to Olefin) reaction, obtained by oxidative coupling of ethylene and methane obtained from dehydration reaction of ethanol Ethylene obtained by various known methods such as ethylene 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 with the manufacturing method of propylene in 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. 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 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 there is no restriction | limiting in particular in the form of the reactor to be used, Usually, a continuous type fixed bed reactor and a fluidized bed reactor are selected. A fluidized bed reactor is preferred.
In order to keep the temperature distribution of the catalyst layer small when the fluidized bed reactor is charged with the above-mentioned catalyst, granular materials inert to the reaction, such as quartz sand, alumina, silica, and silica-alumina, are combined with the catalyst. You may mix and fill. In this case, there is no particular limitation on the amount of granular material inactive to the reaction such as quartz sand. In addition, it is preferable that this 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, paraffins, hydrocarbons such as methane, aromatic compounds, and mixtures thereof, etc. A gas inert to the reaction can be present, and among these, water (water vapor) is preferably present together.

(B) Reaction conditions
<Substrate concentration>
There is no particular limitation on the concentration of ethylene in all the feed components fed to the reactor (ie, the 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 above 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 becomes slow, so a large amount of catalyst is required, and the reactor tends to be too large.
Therefore, it is preferable to dilute ethylene with a diluent described below 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 but is preferably between 0.01 hr ^-1 for 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 about 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 above upper limit, the yield of propylene may be significantly reduced.

<Reaction pressure>
The reaction pressure is not particularly limited, but is usually 2 MPa (absolute pressure, the same shall apply hereinafter) or less, preferably 1 MPa or less, 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 exceeds the upper limit, the amount of undesired by-products such as paraffins increases, and the propylene selectivity tends to decrease. When the reaction pressure is less than the lower limit, the reaction rate tends to be slow.

<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. (For example, the method described in JP2011-78962A)
The regeneration method is not particularly limited, and specifically, for example, regeneration can be performed using air, nitrogen, water vapor, hydrogen or the like, and it is preferable to perform regeneration using hydrogen.

<Conversion rate>
In the present invention, the conversion is not particularly limited, but usually the conversion of ethylene is 20% or more, preferably 40% or more, more preferably 50% or more, and usually 95% or less, preferably 90%. The reaction is preferably performed under the following conditions.
If this conversion rate is less than the lower limit, there are a lot of unreacted ethylene and the propylene yield is low, which is not preferable. On the other hand, when the amount is not less than the upper limit, undesirable by-products such as paraffins increase and the propylene selectivity decreases, which may not be preferable.

When the reaction is carried out in a fluidized bed reactor, the catalyst can be operated at a preferable 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 each of the following formulas, propylene, butene, C ₅ +, paraffin or aromatic compound-derived carbon (mol) means the number of moles of carbon atoms constituting each component. Paraffin is the sum of paraffins having 1 to 3 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 (%) = [Propylene outlet derived carbon (mol / hr) /
[Reactor outlet total carbon (mol / hr) -reactor outlet Eth
Len derived carbon (mol / hr)]] × 100
Butene selectivity (%) = [reactor outlet butene-derived carbon (mol / hr) / [reactor outlet
Total carbon (mol / hr) -reactor outlet ethylene-derived car
Bonn (mol / hr)]] × 100
C ₅ + selectivity (%) = [reactor outlet C ₅ + derived carbon (mol / hr) / [reactor outlet
Total carbon (mol / hr) -reactor outlet ethylene-derived carbon
(Mol / hr)]] × 100
Paraffin selectivity (%) = [Carbon derived from reactor paraffin (mol / hr) /
[Reactor outlet total carbon (mol / hr) -reactor outlet Eth
Len derived carbon (mol / hr)]] × 100
Aromatic compound selectivity (%) = [reactor outlet aromatic compound-derived carbon (mol / hr)
/ [Reactor outlet total carbon (mol / hr)-reactor outlet
Ethylene-derived carbon (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 esters can be produced by selective oxidation, oxo alcohols such as normal butyl alcohol and 2-ethylhexanol 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.
<Pore distribution measurement method>
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 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 relationship between the relative pressure and the adsorption isotherm of water vapor.

<XRD measurement>
XRD measurement was performed based on the following conditions.
-Device name: X'PertPro MPD manufactured by PANalytical, the Netherlands
Measurement conditions X-ray output (CuKα): 45 kV, 40 mA
Scanning axis: θ / 2θ
Scanning range (2θ): 5.0-70.0 °
Measurement mode: Continuous
Reading width: 0.05 °
Counting time: 99.7 sec
Automatic variable slit (Automatic-DS): 1 mm (irradiation width)
Horizontal divergence mask: 10 mm (irradiation width)

(Synthesis Example 1)
25 wt% of 47.3 g of an aqueous solution of N, N, N-trimethyl-1-adamantanammonium hydroxide (N, N, n-trimethyl-1-adamantammonium hydroxide), 4.5 g of sodium hydroxide and 408 g of water After mixing and adding 4.3 g of aluminum hydroxide (50 to 57% by weight in terms of aluminum oxide) and stirring, 33.6 g 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. The resulting gel was charged into an autoclave and heated at 160 ° C. for 42 hours under stirring conditions. The product was filtered, washed with water, and dried at 100 ° C.
After drying, the temperature was raised to 580 ° C. in an air atmosphere over 6 hours, and then calcined by maintaining at 580 ° C. for 6 hours to obtain sodium-type zeolite A.

Using the sodium-type zeolite A obtained above, an H-type zeolite was further produced.
Zeolite A was ion-exchanged with a 1M aqueous ammonium nitrate solution at 80 ° C. for 1 hour, filtered, and further heated with a 1M aqueous ammonium nitrate solution at 80 ° C. for 1 hour for ion exchange. Then, after filtering again and drying at 100 degreeC, it heated up to 500 degreeC by the air atmosphere in 6 hours, and H type zeolite B was obtained by hold | maintaining for 6 hours after that.

(Synthesis Example 2)
5.9 kg of a 25 wt% aqueous solution of N, N, N-trimethyl-1-adamantanammonium hydroxide (N, N, n-trimethyl-1-adamantammonium hydroxide), 0.56 g of sodium hydroxide and 51 kg of water After mixing and adding 0.53 kg of aluminum hydroxide (50 to 57 wt% in terms of aluminum oxide) to this and stirring, 4.2 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. The resulting gel was charged into an autoclave and heated at 160 ° C. for 48 hours under stirring conditions. The product was centrifuged and washed with water, and then dried at 100 ° C.
After drying, it was calcined at 580 degrees in an air atmosphere to obtain a sodium-type zeolite. This zeolite was designated as zeolite C.

The zeolite obtained above is a CHA-type sodium-type aluminosilicate, and the SiO ₂ / Al ₂ O ₃ ratio is 16 (molar ratio).
Using the obtained sodium-type zeolite C, an H-type zeolite was further produced.
Zeolite C was heated at 80 ° C. for 1 hour using a 1M aqueous ammonium nitrate solution for ion exchange. After ion exchange, filtration was performed, and ion exchange was further performed with a 1M ammonium nitrate aqueous solution at 80 ° C. for 1 hour. Then, after filtering again and drying at 100 degreeC, it heated up to 500 degreeC by the air atmosphere in 6 hours, and H type zeolite D was obtained by hold | maintaining for 6 hours after that.

(Synthesis Example 3)
47.3 g of an aqueous solution of 25 wt% N, N, N-trimethyl-1-adamantanammonium hydroxide (N, N, n-trimethyl-1-adamantammonium hydroxide), 4.5 g of sodium hydroxide and 408 g of water After mixing, 7.2 g of aluminum hydroxide (50 to 57% by weight in terms of aluminum oxide) was added and stirred, and then 33.6 g of fumed silica was added as a silica source 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. The resulting gel was charged into an autoclave and heated at 160 ° C. for 42 hours under stirring conditions. The product was filtered, washed with water, and dried at 100 ° C.
After drying, it was calcined at 580 degrees in an air atmosphere to obtain sodium-type zeolite E.
The zeolite obtained above is a CHA-type sodium-type aluminosilicate, and the SiO ₂ / Al ₂ O ₃ ratio is 14 (molar ratio).

Using the obtained sodium-type zeolite E, an H-type zeolite was further produced.
The zeolite E was ion-exchanged with a 1M ammonium nitrate aqueous solution at 80 ° C. for 1 hour, filtered, and further ion-exchanged with a 1M ammonium nitrate aqueous solution at 80 ° C. for 1 hour. Then, after filtering again and drying at 100 degreeC, it heated up to 500 degreeC by the air atmosphere in 6 hours, and H type zeolite F was obtained by hold | maintaining for 6 hours after that.

Example 1
The zeolite A obtained in Synthesis Example 1 was silylated in a sulfuric acid solution. To 0.5 g of zeolite A, 25 g of 0.1 M sulfuric acid as a solvent and 0.15 g of tetraethoxysilane (hereinafter sometimes abbreviated as TEOS) as a silylating agent are added and charged in an autoclave at 100 ° C. for 20 hours. Heat-treated. After the treatment, solid-liquid separation was performed by filtration, and the obtained zeolite was dried at 100 ° C. The catalyst thus obtained was designated as Catalyst 1.

The obtained catalyst 1 was used for ethylene conversion reaction. Using a normal pressure fixed bed flow reactor, a quartz reaction tube having an inner diameter of 6 mm was filled with a mixture of 100 mg of catalyst and 400 mg of quartz sand. A mixed gas of 30% by volume of ethylene and 70% by volume of nitrogen was supplied to the reactor so that the weight space velocity of ethylene was 0.36 Hr ⁻¹ , and the reaction was performed at 400 ° C. and 0.1 MPa. After starting the reaction, the product was analyzed by gas chromatography. Further, the pore volume of the zeolite was measured based on the measurement method. The results are shown in Table 1. About the reaction result, the data 3.0 hours after the reaction start were shown.

(Example 2)
Silylation, filtration, and drying were performed in the same manner as the catalyst preparation method described in Example 1, except that the treatment time was shortened to 6 hours. The catalyst thus obtained was designated as Catalyst 2.
Using the catalyst 2, an ethylene conversion reaction was carried out under the same conditions as in Example 1. The results are shown in Table 1. The reaction results are shown at 3.2 hours after the start of the reaction for comparison at the time when the conversion rate equivalent to the ethylene conversion rate obtained in Example 1 was obtained.

(Example 3)
Silylation, filtration, and drying were performed in the same manner as the catalyst preparation method described in Example 1 except that the amount of sulfuric acid and the amount of tetraethoxysilane were halved. The catalyst thus obtained was designated as Catalyst 3.
Using the catalyst 3, an ethylene conversion reaction was carried out under the same conditions as in Example 1. The results are shown in Table 1. The reaction results were compared at the time when a conversion rate equivalent to the ethylene conversion rate obtained in Example 1 was obtained, and data after 3.4 hours from the start of the reaction are shown.

(Comparative Example 1)
Silylation, filtration, and drying were performed in the same manner as the preparation method described in Example 1 except that zeolite A was changed to zeolite B. The catalyst thus obtained was designated as Catalyst 4.
Using the catalyst 4, an ethylene conversion reaction was carried out under the same conditions as in Example 1. The results are shown in Table 1. About the reaction results, in order to compare when the conversion rate equivalent to the ethylene conversion rate obtained in Example 1 was obtained, data after 3.0 hours from the start of the reaction are shown.

(Comparative Example 2)
Zeolite B was treated with sulfuric acid. 25 g of 0.1M sulfuric acid was added to 0.5 g of zeolite B, charged in an autoclave, and heat-treated at 100 ° C. for 20 hours. After the treatment, solid-liquid separation was performed by filtration, and the obtained zeolite was dried at 100 ° C. The catalyst thus obtained was designated as Catalyst 5.

  Using the catalyst 5, an ethylene conversion reaction was carried out under the same conditions as in Example 1. The results are shown in Table 1. The reaction results were compared at the time when a conversion rate equivalent to the ethylene conversion rate obtained in Example 1 was obtained, and data after 4.0 hours from the start of the reaction are shown.

Example 4
The zeolite C obtained in Synthesis Example 2 was silylated in a sulfuric acid solution. To 1 g of zeolite C, 50 g of 1M sulfuric acid as a solvent and 0.3 g of tetraethoxysilane as a silylating agent were added and charged in an autoclave, followed by heat treatment at 100 ° C. for 20 hours. After the treatment, solid-liquid separation was performed by filtration, and the obtained zeolite was dried at 100 ° C. The catalyst thus obtained was designated as Catalyst 6.

Using the catalyst 6, an ethylene conversion reaction was carried out. Using a normal pressure fixed bed flow reactor, a quartz reaction tube having an inner diameter of 6 mm was filled with a mixture of 100 mg of catalyst and 400 mg of quartz sand. A mixed gas of 30% by volume of ethylene and 70% by volume of nitrogen was supplied to the reactor so that the weight space velocity of ethylene was 0.36 Hr ⁻¹ , and the reaction was performed at 400 ° C. and 0.1 MPa. The product was analyzed by gas chromatography 2.1 hours after the start of the reaction. Further, the pore volume of the zeolite was measured based on the measurement method. The results are shown in Table 1.

(Example 5)
Silylation, filtration, and drying were performed in the same manner as in Example 4 except that the sulfuric acid concentration was changed to 0.5M. The catalyst thus obtained was designated as Catalyst 7.
Using the catalyst 7, an ethylene conversion reaction was carried out under the same conditions as in Example 4. The product was analyzed by gas chromatography 2.1 hours after the start of the reaction. The results are shown in Table 1.

(Example 6)
Silylation, filtration, and drying were performed in the same manner as in Example 4 except that the sulfuric acid concentration was changed to 0.25M. The catalyst thus obtained was designated as Catalyst 8.
Using the catalyst 8, an ethylene conversion reaction was performed under the same conditions as in Example 5. The product was analyzed by gas chromatography 2.1 hours after the start of the reaction. The results are shown in Table 1.

(Example 7)
The zeolite C obtained in Synthesis Example 3 was silylated in a sulfuric acid solution. 25 g of 0.1M sulfuric acid as a solvent and 0.15 g of tetraethoxysilane as a silylating agent were added to 0.5 g of zeolite C, and the mixture was charged in an autoclave and heat-treated at 100 ° C. for 20 hours. After the treatment, solid-liquid separation was performed by filtration, and the obtained zeolite was dried at 100 ° C. The catalyst thus obtained was designated as Catalyst 9.

  Using the catalyst 9, an ethylene conversion reaction was performed under the same conditions as in Example 4. The product was analyzed by gas chromatography 1.4 hours after the start of the reaction. The results are shown in Table 1.

From Examples 1 to 3 shown in Table 1, when a reaction for producing propylene using ethylene as a substrate is performed with catalysts 1 to 3 obtained by silylation treatment of zeolite A which is sodium (Na) type in the presence of sulfuric acid, high selection The rate was obtained. In Examples 1 to 3, since the silylation treatment in sulfuric acid causes the ion exchange reaction and the silylation of the outer surface to occur in a series of reactions, it is considered that the catalyst having the target outer surface silylated was obtained. . Because the outer surface was poisoned by silylation treatment, the shape selectivity was not exhibited, the reaction on the outer surface was suppressed, the production amount of products larger than propylene was reduced, and the propylene selectivity was improved. Conceivable.

From the comparison between Examples 1 to 3 and Comparative Example 1, the results are the same as those obtained after once producing the H-type zeolite and then subjected to the silylation treatment. It can be seen that equivalent performance catalysts can be obtained without reducing certain ion exchanges and calcinations. Thereby, it turns out that the time and energy concerning the conversion process to H type | mold can be reduced.
In addition, from Examples 4 to 6, it was confirmed that the effect of the silylation treatment can be obtained with a wide range of acid concentrations when the zeolite C of sodium (Na) type is subjected to silylation treatment in the presence of sulfuric acid. By performing the silylation treatment, a higher propylene selectivity was obtained as in Examples 1 to 3, compared to zeolite not subjected to the silylation treatment.
In addition, Example 7 showed that zeolite C having a small pore volume can be silylated in the presence of sulfuric acid.

<Confirmation of structure retention>
Next, an example of the retention of the sulfate silylation structure is shown.
(Comparative Example 3)
H-type zeolite F was treated with sulfuric acid. 50 g of 0.1M sulfuric acid was added to 1 g of zeolite F, charged in an autoclave, and heat-treated at 100 ° C. for 20 hours. After the treatment, solid-liquid separation was performed by filtration, and the obtained zeolite was dried at 100 ° C. The zeolite thus obtained was designated as zeolite G, and XRD measurement was performed by the above method together with zeolite F.

Based on the XRD measurement results, the peak intensity at 2θ = 29 ° was compared before and after the treatment to confirm the degree of structural destruction of the zeolite. The results are shown in Table 2. Each XRD pattern is shown in FIG.
In addition, there is no difference in the result of XRD measurement between Na type and H type, and there is no difference in the result of XRD measurement when Na type is ion-exchanged and converted to H type. Therefore, the effect of the acid on the zeolite was confirmed using the H-type once.

(Reference Example 1)
H-type zeolite D was silylated in a sulfuric acid solution. Zeolite D 0.5g
25 g of 0.1M sulfuric acid as a solvent and 0.15 g of tetraethoxysilane as a silylating agent were added to an autoclave and heat-treated at 100 ° C. for 20 hours. After the treatment, solid-liquid separation was performed by filtration, and the obtained zeolite was dried at 100 ° C. The zeolite thus obtained was designated as zeolite H, and XRD measurement was performed together with zeolite D.

  From the measurement results of XRD, the degree of structural destruction of the zeolite was confirmed by the same method as in Comparative Example 3. The results are shown in Table 2. Each XRD pattern is shown in FIG.

From Comparative Example 3, it can be seen that the peak intensity at 2θ = 29 ° decreased to 64% after the sulfuric acid treatment. From this, it can be seen that when the zeolite is subjected to acidic conditions, the structure collapses.
On the other hand, it was found from Reference Example 1 that the structure of the zeolite was maintained even when the H-type zeolite was silylated by the silylation method of the present invention. In general, when the same amount of zeolite is treated with the same amount of acid, the H-type treatment tends to be fragile because it is treated under severer conditions, but the structure is maintained.

  From Comparative Example 2, it can be seen that when the same reaction was carried out with the catalyst 5 obtained by treating H-type zeolite B with sulfuric acid, the propylene selectivity was lowered. This is presumably because the structure of the zeolite was destroyed by the sulfuric acid treatment and the performance as a catalyst was lowered. From the comparison between Comparative Example 2 and Examples 1 to 3, it can be seen that if a silylating agent coexists, structural destruction does not occur and the sodium (Na) type can be directly converted to the silylated H type.

  The present invention can provide a method for producing an H-type zeolite having a silylated CHA-type structure by a simple method. Propylene can be efficiently produced by producing propylene from ethylene using the H-type zeolite obtained by this method.

Claims (8)

A method for producing an H-type zeolite having a silylated CHA-type structure,
A method for producing a H-type zeolite having a silylated CHA-type structure, characterized by reacting a non-H-type zeolite having a CHA-type structure with a silylating agent in the presence of an acidic aqueous solution. 2. The total pore volume in the range of 100 to 200 μm in pore diameter distribution obtained by the BJH method from the nitrogen adsorption isotherm of the non-H zeolite is 10 × 10 ⁻³ ml / g or more. A process for producing an H-type zeolite having a silylated CHA structure as described in 1.   The silylated CHA type structure according to claim 1 or 2, wherein the non-H type zeolite is substituted with any one of an alkali metal ion, an alkaline earth metal ion, and an ammonium ion. The manufacturing method of the H-type zeolite which has this.   The method for producing an H-type zeolite having a silylated CHA-type structure according to any one of claims 1 to 3, wherein the non-H-type zeolite is an aluminosilicate.   The manufacturing method of the H-type zeolite which has the silylated CHA type structure of any one of Claims 1-4 whose density | concentration of the acid in the said acidic aqueous solution is 0.01M or more and 5M or less.   The method for producing an H-type zeolite having a silylated CHA-type structure according to any one of claims 1 to 5, wherein the acidic aqueous solution is sulfuric acid. _SiO 2 _/ M 2 _{O 3} ratio of the non-H-type zeolite, 5 or more and 50 or less, the H-type zeolite having a silylated CHA structure according to any one of claims 1 to 6 Production method.   A method for producing propylene, characterized in that propylene is produced from ethylene as a raw material using the silylated H-type zeolite obtained by the production method according to any one of claims 1 to 7 as a catalyst.

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