JP2021059484A - Novel silver-containing zeolite and zeolite-containing catalyst for producing aromatic hydrocarbons - Google Patents

Abstract

To provide a novel silver-containing zeolite having a specific trace amount of Bronsted acid points on its surface and a catalyst for producing aromatic hydrocarbons containing the silver-containing zeolite, which is expected to be useful as a catalyst for the aromatization of non-aromatic hydrocarbons such as aliphatic hydrocarbons.SOLUTION: A silver-containing zeolite which contains silver and satisfies the following properties (i) to (iv): (i) Average particle size is 100 nm or less. (ii) 10-membered ring pore zeolite. (iii) The content of silver is 0.05 to 3 wt%. (iv) The amount of Bronsted acid on the outer surface is 0.1 to 10.0 μmol/g.SELECTED DRAWING: None

Description

The present invention relates to a novel silver-containing zeolite which is a 10-membered ring-pore zeolite containing silver and having a specific amount of blended acid points on the outer surface, and a catalyst for producing an aromatic hydrocarbon containing the same. More specifically, by having a specific average particle size, a trace amount of zeolite acid spot on the outer surface, and a specific amount of silver, the action as a catalyst for producing aromatic hydrocarbons, which is excellent in the production efficiency of aromatic hydrocarbons, and It relates to a novel silver-containing zeolite, which is a durable 10-membered ring-pore zeolite.

For benzene, toluene, and xylene (hereinafter, may be collectively referred to as aromatic compounds), in many cases, raw material oil (for example, naphtha) obtained by petroleum refining is used in a pyrolysis reaction device. It is obtained by decomposition and separation and purification of an aromatic compound from the obtained thermal decomposition product by distillation or extraction. In the production of aromatic compounds by these, aliphatic and / or alicyclic hydrocarbons are included as thermal decomposition products other than aromatic compounds. Therefore, the aliphatic and / or alicyclic hydrocarbons are produced at the same time as the aromatic compound is produced, so that the production amount of the aromatic compound is commensurate with the production amount of the aliphatic and / or alicyclic hydrocarbons. Adjustments were made, and the production volume was naturally limited.

Zeolites are widely used industrially as petrochemical catalysts, exhaust gas purification catalysts for internal combustion engines, adsorbents, and the like. Then, in industrial use, for the purpose of improving durability and handleability, a binder (for example, silica, clay mineral, etc.) is mixed, molded into a predetermined shape, and sintered by high-temperature firing. It has been used as a zeolite molded product in which a zeolite and a binder are combined.

Further, medium-pore zeolite and zeolite complex are used as highly selective catalysts utilizing pores having a size equivalent to that of an aromatic compound. Disproportionation of toluene, isomerization of xylene, and the like have been proposed as examples of using MFI-type zeolite as a catalyst, which is a typical example of such zeolite. These reactions mainly utilize the characteristics of the micropores of zeolite. The micropores of the medium-pore zeolite have an inlet diameter of about 0.5 nm, and are considered to be an effective reaction field for molecules having a molecular diameter close to the pore diameter.

Then, a method for producing an aromatic compound by contacting an aliphatic or alicyclic hydrocarbon raw material with a catalyst mainly containing medium pore size zeolite at a temperature of about 400 ° C. to about 800 ° C. (for example). Patent Documents 1 and 2) have been proposed. Compared with the method for producing an aromatic compound by thermal decomposition, these production methods have an effect that the added value is low and the aromatic compound can be produced from a non-aromatic compound which is a surplus hydrocarbon as a raw material. On the other hand, there are still problems in terms of production efficiency and selectivity.

Further, in a reaction using a zeolite as a catalyst, a zeolite from which acid spots on the surface have been removed (see, for example, Patent Document 3) has been proposed. A reaction at the acid point on the zeolite surface (outer surface) is also known, and this reaction is generally considered to be a non-selective reaction. These non-selective reactions often induce a decrease in product yield, a decrease in product selectivity, catalyst inactivation due to cork precipitation, etc., and are judged to be undesirable.

As a method of suppressing such a non-selective reaction, a method of extracting aluminum on the surface with a bulky reagent or coating the surface has been proposed. Specifically, a zeolite having an MFI structure is coated with silicate. A method for selectively producing p-xylene (see, for example, Patent Document 4), a method for coating the surface acid spot of zeolite with a bulky dialkylamine reagent (see, for example, Patent Documents 5 and 6), and the like have been proposed. There is.

Further, not only on the surface and inside, the acidity of zeolite decreases with time by heating or dealumination in a hydrothermal atmosphere. This phenomenon is an unavoidable problem when zeolite is used as a catalyst. The heating or hydrothermal atmosphere is due to use at a high temperature exceeding 400 ° C. or use in an environment where water vapor is generated. In particular, the latter applies to the catalyst regeneration step of burning the coke in an atmosphere containing oxygen with respect to the catalyst after the coke precipitation.

One method of suppressing the dealumination of zeolite is the protection of acid spots with an additive metal. For example, a method of improving the heat resistance and water heat resistance of zeolite by adding silver to the zeolite to protect the acid point has been proposed (see, for example, Non-Patent Document 1).

Patent No. 3741455 Patent No. 3264447 Japanese Unexamined Patent Publication No. 2018-145085 Patent No. 6029654 U.S. Pat. No. 4,502,221 U.S. Pat. No. 4,568,768

Physical Chemistry Chemical Physics Vol. 17, p. 15637 (2015)

However, although the method proposed in Patent Document 3 has a certain effect in the production of aromatic hydrocarbons, it removes acid spots on the surface of zeolite, so that the production efficiency and selectivity of aromatic hydrocarbons are improved. Then, there was still room for improvement. Further, the method proposed in Patent Document 4 has a problem that hydrothermal synthesis is required a plurality of times when the zeolite is coated with a hydrocarbon, and p-xylene is selectively produced, and is aromatic. No consideration has been given to the selective and efficient production of hydrocarbons. Further, the methods proposed in Patent Documents 5 and 6 propose coating of surface acid spots with amines, and since amines are likely to be desorbed or decomposed at high temperatures, they should be used at high temperatures. There is a problem in stability as a catalyst for producing aromatic hydrocarbons, which is a prerequisite. Further, in the method proposed in Non-Patent Document 1, the amount of acid of zeolite is not specified, and there is still room for improvement in terms of production efficiency and selectivity of aromatic hydrocarbons.

Therefore, as a result of diligent studies to solve the above problems, the present inventors selectively removed only the Bronsted acid spots on the surface of the zeolite and provided a specific amount of a small amount of Bronsted acid spots on the outer surface. In addition to having it, by further containing a specific amount of silver, it exhibits high heat resistance and water heat resistance in the production of aromatic hydrocarbons, and also improves caulking resistance, reaction life and productivity, and exhibits excellent performance. We have found that this is the case, and have completed the present invention.

That is, the present invention relates to a silver-containing zeolite containing silver and satisfying the following characteristics (i) to (iv), and a catalyst for producing an aromatic hydrocarbon containing the same. As a production method at that time, for example, a method of introducing silver into a zeolite having the following characteristics (i), (ii), and (iv) by impregnation loading, ion exchange, skeleton substitution, or the like can be mentioned. In that case, an aqueous silver nitrate solution or the like can be used.
(I) The average particle size is 100 nm or less.
(Ii) 10-membered ring pore zeolite.
(Iii) The silver content is 0.05 to 3 wt%.
(Iv) The amount of Bronsted acid on the outer surface is 0.1 to 10.0 μmol / g.

Hereinafter, the present invention will be described in detail.

The novel silver-containing zeolite of the present invention has (i) an average particle size (hereinafter, also referred to as PD) of PD ≦ 100 nm, (ii) a 10-membered ring-pore zeolite, and (iii) a silver content. It satisfies any of the requirements of 0.05 to 3 wt% and (iv) zeolite on the outer surface of 0.1 to 10.0 μmol / g.

The novel silver-containing zeolite of the present invention has (i) PD ≦ 100 nm, and is particularly excellent in thermal stability. Therefore, it is desirable that 5 nm ≦ PD ≦ 100 nm. Here, when PD exceeds 100 nm, the reaction efficiency is inferior when it is used as a catalyst for a hydrocarbon conversion reaction.

The measurement method of PD in the present invention is not limited. For example, 100 or more arbitrary particles are selected from photographs of a scanning electron microscope (SEM) or a transmission electron microscope (TEM), and the average diameter thereof is obtained. Any method can be mentioned, such as a method, a method of calculating from the outer surface surface of zeolite using the following formula (1), and the like.
PD = 6 / S × (1 / (2.29 × 10 ⁶ ) + 0.18 × ^10-6 ) (1)
(Here, S indicates the outer surface area (m ² / g).)
The outer surface area (S (m ² / g)) in the formula (1) can be obtained from the t-prot method using a general nitrogen adsorption method at a liquid nitrogen temperature. For example, when t is the thickness of the adsorption amount, the measurement points in the range of 0.6 to 1 nm are linearly approximated with respect to t, and the outer surface area of the zeolite is obtained from the slope of the obtained regression line.

And, above all, the method by SEM or TEM is preferable because simple measurement is possible.

The novel silver-containing zeolite of the present invention is (ii) a 10-membered ring-pore zeolite, and any zeolite having a skeleton structure having a 10-membered ring structure and pores may be used, and the 10-membered ring may be used. Specific examples of the zeolite having a pore structure include zeolites of AEL, EUO, FER, HEU, MEU, MEL, MFI, NES type and the like, and particularly for producing aromatic hydrocarbons of aliphatic hydrocarbons. It is preferably MFI type or MEL type because it is expected as a catalyst. And, for example, as the MFI type, an aluminosilicate compound belonging to the structure code MFI defined by the International Zeolite Society can be mentioned.

The novel silver-containing zeolite of the present invention has a (iii) silver content of 0.05 to 3 wt%, and has a silver content within a specific range when used as a catalyst for producing aromatic hydrocarbons. It exhibits particularly excellent catalytic performance. Here, when the silver content is less than 0.05 w%, the effect of protecting the acid point by silver cannot be obtained, and the production efficiency and selectivity of the catalyst performance when used as a catalyst for producing aromatic hydrocarbons are inferior. It becomes a thing. On the other hand, when it is larger than 3 w%, silver agglutination proceeds, side reactions and caulking on the surface of the silver agglutinated particles are likely to occur, and the catalytic performance is deteriorated.

The novel silver-containing zeolite of the present invention has a (iv) outer surface Bronsted acid amount (hereinafter, may be referred to as B acid amount) of 0.1 to 10.0 μmol / g, which is within a specific range. By having the amount of B acid on the outer surface of the above, the catalyst performance is particularly excellent when it is used as a catalyst for producing aromatic hydrocarbons. Here, when the amount of B acid on the outer surface is less than 0.1 μmol / g, the production efficiency and selectivity of the catalyst performance when used as a catalyst for producing aromatic hydrocarbons are inferior. On the other hand, when it is larger than 10.0 μmol / g, side reactions and caulking on the catalyst surface are likely to occur, and the catalyst performance is deteriorated.

In the novel silver-containing zeolite of the present invention, when it is used as a catalyst for producing aromatic hydrocarbons, it becomes a catalyst having excellent production efficiency and selectivity of aromatic hydrocarbons. Therefore, (v) the amount of B acid is 0. It is preferably 0.01 to 1.0 mmol / g, and particularly preferably 0.01 to 0.2 mmol / g.

Here, the B acid amount of the zeolite indicates the amount of the Bronsted acid point (hereinafter, may be referred to as the B acid point), and indicates the acidic OH group present in the zeolite. Zeolites usually have B acid points on their outer surface and in (micro) pores. And, having only a few B acid points on the outer surface means that most of the B acid points are present in the (micro) pores.

As a method for confirming the amount of B acid on the outer surface of the novel silver-containing zeolite of the present invention, any method can be used as long as the confirmation can be performed. It can be confirmed by the adsorption of 2,4-dimethylquinoline. 2,4-Dimethylquinoline has an adsorptive property with the B acid point (acidic OH group) present in zeolite (including in the pores). However, when the (micro) pore diameter of the zeolite is smaller than the 2,4-dimethylquinoline molecule as in the MFI type, it cannot penetrate into the (micro) pores and the B acid point in the (micro) pores. Cannot be adsorbed. That is, it adsorbs only the B acid point on the outer surface of the zeolite. Therefore, the amount of B acid on the outer surface can be quantified by determining the amount of 2,4-dimethylquinoline adsorbed on the B acid point on the outer surface of the MFI-type zeolite.

As a more specific method, infrared absorption spectrum measurement at 150 ° C. of zeolite which has been degassed and dehydrated at 400 ° C. for 2 hours as a pretreatment of zeolite is performed. Then, 2,4-dimethylquinoline gas is introduced into the degassed / dehydrated zeolite and adsorbed for 30 minutes, and excess 2,4-dimethylquinoline is removed by exhaust at 150 ° C. to remove 2,4-dimethylquinoline. The adsorbed zeolite is prepared and the infrared absorption spectrum is measured at 150 ° C. That is, the amount of B acid on the outer surface can be obtained by quantifying the difference (decrease) in infrared absorption in the range of ^{3600 to 3650 cm -1} in the infrared absorption difference spectrum before and after adsorption of 2,4-dimethylquinoline. it can. Although 2,4-dimethylquinoline is also adsorbed on the silanol site on the zeolite surface, absorption derived from the oh expansion and contraction vibration of silanol is observed at ^{3700 to 3800 cm -1.} On the other hand, the absorption derived from the OH expansion and contraction vibration of the B acid point on the outer surface of the zeolite ^{was observed at 3600 to 3650 cm -1} , adsorbing 2,4-dimethylquinoline and the OH expansion and contraction vibration of the B acid point. The decrease in the infrared absorption spectrum in the range of absorption 3600 to 3650 cm ^-1 derived from the above indicates that 2,4-dimethylquinoline was adsorbed on the B acid point on the outer surface of the zeolite.

Further, as a method for measuring the amount of B acid (B acid point existing on the outer surface and in the (micro) pores) of the novel silver-containing zeolite of the present invention, any method can be used as long as the measurement can be performed. Can also be used, for example, it can be confirmed by adsorption of pyridine having adsorptivity to the B acid point. Pyridine has an adsorption property with the B acid point (acidic OH group) existing in the zeolite (including in the pores), and when the (micro) pore diameter of the zeolite is larger than the pyridine, the (micro) pores It can also penetrate inside and can adsorb both the outer surface and the B acid points in the (micro) pores. Therefore, the amount of B acid present in the zeolite can be quantified, including the B acid point existing in the pores of the MFI type zeolite.

As a more specific method, infrared absorption spectrum measurement at 150 ° C. of zeolite which has been degassed and dehydrated at 400 ° C. for 2 hours as a pretreatment of zeolite is performed. Then, pyridine gas is introduced into the degassed / dehydrated zeolite and adsorbed for 10 minutes, excess pyridine is removed by exhaust at 150 ° C., pyridine-adsorbed zeolite is prepared, and infrared absorption spectrum measurement at 150 ° C. is performed. Do. That is, in the infrared absorption difference spectrum before and after pyridine adsorption, the amount of B acid including the inside of the pores can be obtained by quantifying the difference (increase) in infrared absorption in the range of ^{1515 to 1565 cm -1.}

The novel silver-containing zeolite in the present invention is a catalyst having excellent production efficiency and selectivity of aromatic hydrocarbons, particularly when it is used as a catalyst for producing aromatic hydrocarbons. Therefore, a slight amount of B acid is applied to the outer surface. It is preferable that the B acid points have points and most of the B acid points are present in the (micro) pores, and the B acid points present on the outer surface thereof are 1 to 10% of the total B acid points. It is preferable to have. The ratio of the B acid point on the outer surface is determined by using the amount of B acid on the outer surface of the above-mentioned zeolite as the ratio of the amount of B acid present in the zeolite (including the inside of the pores).

As a novel method for producing a silver-containing zeolite of the present invention, any method can be used as long as it is possible to produce a zeolite satisfying the characteristics described in (i) to (iv) above. Then, a zeolite having a specific amount of a small amount of B acid point on the outer surface, that is, a zeolite satisfying the characteristics of (i) to (ii) is produced as a method for selectively removing the B acid point on the zeolite surface. Examples thereof include a method in which a part or all of the firing treatment (heat treatment) is treated as a hydrothermal (steam) treatment, and an ion exchange treatment is added before and after the firing treatment.

Then, as a method for synthesizing the zeolite satisfying the characteristics (i) to (ii), a generally known method is used to obtain a zeolite having a skeleton structure of PD ≦ 100 nm and 10-membered ring pores. Can be done. Specifically, it can be produced by mixing a compound containing an alkali metal and / or an alkaline earth metal as a cation, an organic structure-directing agent and an aluminosilicate gel, and calcining the obtained crystal product. Examples of the compound containing an alkali metal and an alkaline earth metal at that time include sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide and the like, and sodium hydroxide is particularly preferable. Examples of the organic structure-directing agent include tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, and tetraethylammonium hydroxide. Moreover, as an aluminosilicate gel, for example, an amorphous aluminosilicate gel and the like can be mentioned.

Further, in order to obtain a zeolite that satisfies the characteristics of (i) to (iv), ion exchange is performed before firing the crystal obtained as described above, and a part or all of the firing is subjected to hydrothermal treatment. After that, it can be produced by a method of further ion exchange, a method of calcining the crystal obtained as described above, then ion exchange to obtain a proton-type zeolite, and then calcining in a hydrothermal atmosphere. Become.

As the firing conditions at that time, the treatment temperature is preferably 300 to 900 ° C, particularly preferably 400 to 700 ° C. The treatment time is industrially preferably 5 minutes to 25 hours. The atmosphere may also include, for example, nitrogen, air, oxygen, argon, or any other combination of one or more of the inert gases. Then, by performing a hydrothermal (steam) treatment on a part or all of the firing step, the aluminum at the B acid point is desorbed. The treatment temperature of the hydrothermal treatment is preferably 400 to 750 ° C, particularly preferably 500 to 650 ° C. The water vapor concentration is preferably 5 to 100%, particularly preferably 10 to 80%.

Further, the ion exchange is performed before and after the firing step, and may be divided into a plurality of times of ion exchange. Further, the ion exchange includes ion exchange using an acid such as ammonium chloride, hydrochloric acid and nitric acid, and those using hydrochloric acid and nitric acid are preferable. In addition, ion exchange can be replaced by washing with water.

Then, silver can be introduced by a method such as impregnation support with an aqueous silver nitrate solution, ion exchange, or skeleton substitution. The introduction of silver may be performed after shaping the shape of the zeolite.

Since the novel silver-containing zeolite of the present invention acts as a catalyst having excellent productivity and selectivity in producing aromatic hydrocarbons from aliphatic hydrocarbons, it is used for producing aromatic hydrocarbons containing the zeolite. It will exhibit excellent performance as a catalyst.

When a catalyst for producing an aromatic hydrocarbon is used, it is preferable to impart a shape as a molded product because the catalyst is excellent in handleability and catalytic performance. When the shape is imparted, it may be molded by any method. For example, a method in which zeolite powder is directly molded into a predetermined shape by compression molding or the like to form a molded product, a predetermined ratio of binder is mixed with zeolite, and in some cases, the zeolite is mixed. Examples thereof include a method in which further additives and the like are mixed at a predetermined ratio and the mixture is molded into a predetermined shape to form a molded product, and further, a method in which sintering is accompanied to form a molded product can be mentioned. When the novel silver-containing zeolite of the present invention is used as a catalyst for producing aromatic hydrocarbons, it not only has excellent moldability as a molded product, but also exhibits high crushing strength and excellent handleability and catalyst life. Therefore, it is preferable that the molded product is made of the zeolite and the binder, and it is more preferable that the molded product is made of the zeolite and silica because it exhibits better catalytic performance. The silica at that time may be any silica as long as it belongs to the category called silica, and may have a specific crystal structure or may be non-crystalline. Furthermore, there are no restrictions on the particle size, aggregation diameter, etc. of silica. In addition, the blending ratio of the zeolite and silica is arbitrary, and since it is a catalyst for producing aromatic hydrocarbons which exhibits particularly excellent catalyst performance, handleability, and catalyst life, the zeolite: silica = 50 to 95:50. It is preferably ~ 5 (weight ratio), and particularly preferably 60 to 90:40-10.

The aromatic hydrocarbon production catalyst may have any shape, for example, a polygonal prism shape such as a cylindrical shape, a cylindrical shape, a triangular prism shape, a square prism shape, a pentagonal prism shape, a hexagonal prism shape, or a hollow polymorphic shape. Examples thereof include a prismatic shape and a spherical shape. Among them, a cylindrical shape and a cylindrical shape are preferable because the catalyst has excellent continuous productivity and high crushing strength. In addition, the size such as diameter, width and length, bulk density, density such as true density can be arbitrarily selected in consideration of filling efficiency, etc., and it is possible to effectively produce aromatic hydrocarbons in particular. Therefore, it preferably has a cylindrical shape having a diameter of 1 to 10 mm or a cylindrical shape having a thickness of 0.5 to 5.0 mm. Further, the catalyst for producing an aromatic hydrocarbon may be one in which an arbitrary metal species typified by silver is introduced by further treatments such as loading, ion exchange, physical mixing, and vapor deposition.

The catalyst for producing aromatic hydrocarbons has high heat resistance and water heat resistance because it suppresses dealumination of zeolite due to high temperature and steam. Further, it has a specific amount of acid points on the surface. Therefore, for example, when it is used for a hydrocarbon conversion reaction or an isomerization reaction, it has high caulking resistance, reaction life and productivity. For example, by contacting a non-aromatic hydrocarbon, for example, a non-aromatic hydrocarbon having 4 to 6 carbon atoms as a raw material, it is possible to produce an aromatic hydrocarbon particularly efficiently. In order to produce aromatic hydrocarbons with higher efficiency, the non-aromatic hydrocarbon raw material is preferably 20% by mass or more, more preferably 50% by mass or more, and further preferably 70% by mass of non-aromatic hydrocarbons having 4 to 6 carbon atoms. It preferably contains aromatic hydrocarbons. At that time, any non-aromatic hydrocarbon having 4 to 6 carbon atoms can be mentioned as long as it belongs to the category, for example, saturated aliphatic hydrocarbon, unsaturated aliphatic hydrocarbon, alicyclic hydrocarbon. Hydrogen, mixtures thereof and the like can be mentioned, and more specifically, n-butene, isobutane, 1-butene, 2-butene, isobutene, butadiene, cyclobutene, cyclobutane, n-pentane, 1-pentane, 2- Pentan, 1-pentene, 2-pentene, 3-pentene, n-hexane, 1-hexane, 2-hexane, 1-hexene, 2-hexene, 3-hexene, hexadiene, cyclohexane and mixtures thereof can be mentioned. it can. In some cases, the raw material component other than the non-aromatic hydrocarbon having 4 to 6 carbon atoms contained in the raw material may be any compound containing a carbon component, for example, 1 to 1 carbon number. Examples thereof include hydrocarbons of 3, hydrocarbons having 7 to 15 carbon atoms, oxygen-containing compounds (alcohol, ether, carboxylic acid, ketone, etc.), and nitrogen-containing compounds (amine, etc.), which efficiently produce aromatic hydrocarbons. From the viewpoint, a hydrocarbon having 1 to 3 carbon atoms or a hydrocarbon having 7 to 10 carbon atoms is preferable.

In the production of aromatic hydrocarbons using the catalyst for producing aromatic hydrocarbons, the reaction temperature is not particularly limited as long as the aromatic hydrocarbons can be produced, and among them, olefins or The range of 400 to 800 ° C. is desirable because it suppresses the formation of alkanes and provides an efficient method for producing aromatic hydrocarbons that does not require an unnecessarily heat-resistant reactor. Further, the reaction pressure is not limited, and the operation can be performed in a pressure range of, for example, about 0.05 MPa to 5 MPa. The supply of the reaction raw material to the aromatic hydrocarbon production catalyst is not particularly limited as the ratio of the volume of the raw material gas to the volume of the catalyst, and the space velocity ^{is, for example, about 1h -1 to} 50,000h ^-1. Can be mentioned. When supplying a hydrocarbon as a raw material gas, a single gas of a specific hydrocarbon, a mixed gas, and a single or mixed gas selected from an inert gas such as nitrogen, hydrogen, carbon monoxide, and carbon dioxide. It can also be used as diluted with.

There is no limitation on the reaction type when producing aromatic hydrocarbons, for example, fixed bed, transport bed, fluidized bed, moving bed, multi-tube reactor as well as continuous flow type, intermittent flow type and swing type reactor. , Etc. can be used.

The aromatic hydrocarbons produced are not particularly limited as long as they belong to the category called aromatic hydrocarbons. For example, benzene, toluene, xylene, trimethylbenzene, ethylbenzene, propylbenzene, butylbenzene, etc. Examples thereof include naphthalene and methylnaphthalene, and benzene, toluene and xylene are particularly preferable.

The novel 10-membered ring pore silver-containing zeolite having a specific average particle size and a trace amount of B acid on the outer surface of the present invention has excellent production efficiency and selectivity when used as a catalyst for producing aromatic hydrocarbons. It is possible to produce aromatic hydrocarbons with heat resistance, water heat resistance, coking resistance, and long life, and its industrial usefulness is expected.

It is a figure which shows the infrared absorption spectrum of the zeolite (before and after adsorption of 2,4-dimethylquinoline) obtained in Examples 1, 2 and 3 and Comparative Examples 1, 2 and 3. It is a figure which shows the infrared absorption spectrum of the zeolite (before and after pyridine adsorption) obtained in Examples 1, 2 and 3 and Comparative Examples 1, 2 and 3. It is a figure which shows the infrared absorption spectrum of the zeolite (before and after adsorption of 2,4-dimethylquinoline) obtained in Examples 4 and 5. It is a figure which shows the infrared absorption spectrum of the zeolite (before and after pyridine adsorption) obtained in Examples 4 and 5.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples.

The 10-membered ring-pore zeolite used in Examples and Comparative Examples was prepared based on Japanese Patent No. 60070336. The catalyst for producing zeolite and aromatic hydrocarbon was measured by the following method.

~ Measurement of average particle size ~
The average particle size was measured with a transmission electron microscope (hereinafter, may be referred to as TEM) and a scanning electron microscope (hereinafter, may be referred to as SEM). For TEM, a transmission electron microscope (manufactured by JEOL Ltd., (trade name) JEM-2100, acceleration voltage 200 kV, observation magnification 30,000 times) was used, and a sample lightly crushed in a dairy pot was ultrasonically dispersed in acetone. A sample was taken as a sample for a microscope, which was dropped on a plastic support film and naturally dried. For each primary particle in the photograph, the average of the diameters in the direction perpendicular to the longest diameter and its midpoint was measured, and the average of a total of 300 particles was taken as the average particle diameter.

The SEM is a scanning electron microscope (manufactured by KEYENCE CORPORATION, (trade name) VE-9800, acceleration voltage 20 kV, observation magnification 2000 times), and a sample lightly crushed in a dairy pot is placed on a sample table and gold-deposited. Was used as a sample for microscopy, and a photograph was taken. The length of one side of 150 particles in the photograph was measured, and the average value was taken as the average crystal diameter.

~ 2,4-Dimethylquinoline adsorption infrared absorption spectroscopy ~
The infrared absorption spectroscopy was measured by a transmission method using an FT-IR measuring device ((trade name) FT / IR-6700, manufactured by Nippon Spectroscopy Co., Ltd.). A spectrum was obtained after 256 integrations using an MCT detector. The sample was formed into a disc having a diameter of 13 mm and then placed vertically on the infrared optical path by placing the sample in a disc holder in a quartz vacuum degassing cell. As a pretreatment of the sample, the temperature was raised to 400 ° C. at 10 ° C./min under vacuum exhaust and held for 2 hours. After cooling to 150 ° C., the infrared absorption spectrum before adsorption of 2,4-dimethylquinoline was measured. 2,4-Dimethylquinoline gas was introduced, adsorbed for 30 minutes, evacuated at 150 ° C. for 1 hour, and then the infrared absorption spectrum after adsorbing 2,4-dimethylquinoline was measured. The difference between the infrared absorption spectrum after adsorption of 2,4-dimethylquinoline and the spectrum before adsorption was taken, and the change in infrared absorption due to adsorption was measured. Of this difference spectrum, ^{the peak near 3600 cm -1 is} the peak of the absorption spectrum of 2,4-dimethylquinoline adsorbed on Bronsted acid, and after determining this area intensity, Lamber-berr's law The amount of B acid was calculated from the following formula (2).
Amount of B acid (μmol / mg) = A · S / (W · ε) (2)
(Here, A; peak area intensity of the target peak (cm ^-1 ), S; sample cross-sectional area (cm ² ), W; sample weight (mg), ε; integral extinction coefficient, 3.7 cm · μmol. ^-1 and each are shown.)
~ Pyridine adsorption infrared absorption spectroscopy ~
In the above 2,4-dimethylquinoline adsorption infrared absorption spectroscopic measurement, only the point where pyridine gas was introduced and adsorbed for 10 minutes was changed, and the measurement was carried out by the same apparatus and the same method.

^{However, the peak near 1545 cm -1} in the difference spectrum is used as the peak of the absorption spectrum of pyridine adsorbed on Bronsted acid, the integrated absorption coefficient is 1.67 cm · μmol ^-1 , and the amount of B acid is calculated from the above formula (2). Asked.

~ Measurement of the shortest distance from the outermost side of the molded body to the center of the molded body (center of the cross section of the molded body) or the side surface of the molded body cylinder ~
30 randomly selected molded particles were measured using calipers, and the average was used as the measured value.

~ Measurement of powder X-ray diffraction ~
It was measured in the atmosphere using an X-ray diffraction measuring device (manufactured by Spectris, (trade name) X'pert PRO MPD), using CuKα1 as a tube voltage of 45 kV and a tube current of 40 mA. The range of 0.04 to 5 degrees was analyzed at 0.08 degrees / step and 200 seconds / step. In addition, the background corrected by the absorption rate of the direct beam is removed.

The crystal structure was identified by visually confirming the presence or absence of peaks. As another method, a peak search program may be used. As the peak search program, a general program can be used. For example, when the measurement results of 2θ (degrees) on the horizontal axis and intensity (a.u.) on the vertical axis are smoothed by the SAVITSKY & GOLAY equation and the Sliding Polynomial filter, and then the second derivative is performed, three or more points are continuous. If there is a negative value, it can be determined that a peak exists.

-Aromatic hydrocarbon production equipment and its production method-
Using the catalysts obtained in Examples and Comparative Examples, aromatic hydrocarbons were produced by the following methods, and the performance as a catalyst for producing aromatic hydrocarbons was evaluated.

A fixed-floor gas-phase flow reactor having a stainless steel reaction tube (inner diameter 16 mm, length 600 mm) was used. The middle stage of the stainless steel reaction tube was filled with a molded product, pretreated by heating under a dry air flow, and then the raw material gas was fed. Then, a ceramic tube furnace was used for heating, and the temperature of the catalyst (mold) layer was controlled. The reaction outlet gas and the reaction solution were collected, and the gas component and the liquid component were analyzed individually using a gas chromatograph. The gas component is a gas chromatograph (manufactured by Shimadzu Corporation, (trade name) GC) equipped with a TCD detector and having a filler (manufactured by Waters Corp., (trade name) PorapakQ or GL Science Co., Ltd., (trade name) MS-5A). -1700) was used for analysis. The liquid components were analyzed using a gas chromatograph (manufactured by Shimadzu Corporation, (trade name) GC-2015) equipped with a FID detector and having a capillary column (manufactured by GL Science, Inc. (trade name) TC-1) as a separation column. ..

The reaction conditions were set as follows.

(Aromatic hydrocarbon production conditions)
Catalyst weight: 3.8 g.
Flowing gas: Mixed gas reaction temperature of 50 mol% of raw material gas + 50 mol% of nitrogen: 590 ° C.
Reaction time: 48 hours.

(Pretreatment conditions)
Catalyst temperature: 590 ° C.
Flowing gas: Air 100 Nml / min.
Processing time: 1 hour.

After a 48 hour reaction, the regenerated gas was fed. As in the reaction, a ceramic tube furnace was used for heating, and the temperature of the catalyst (mold) layer was controlled.

The playback conditions were set as follows.
Catalyst temperature: 590 ° C.
Processing time: 41 hours.
Regenerated gas: Air 20-50 Nml / min.

After 41 hours of regeneration, a cycle of feeding the reaction gas again was performed 30 times in total.

Example 1
Atypical aluminosilicate gel was added to an aqueous solution of tetrapropylammonium (hereinafter sometimes abbreviated as TPA) hydroxide and sodium hydroxide and suspended. MFI-type zeolite was added as a seed crystal to the obtained suspension to prepare a raw material composition. The amount of the seed crystal added at that time was 0.7% by weight with respect to the weight _{of Al 2} O ₃ and SiO _{2 in the raw material composition.} In addition, the by-produced ethanol was removed by evaporation.

The composition of the raw material composition is as follows.
SiO ₂ / Al ₂ O ₃ molar ratio = 48, TPA / Si molar ratio = 0.05, Na / Si molar ratio = 0.16, OH / Si molar ratio = 0.21, H ₂ O / Si molar ratio = 10
The obtained raw material composition was sealed in a stainless steel autoclave and crystallized for 4 days with stirring at 115 ° C. to obtain a slurry-like mixed solution. The slurry-like mixed solution after crystallization was solid-liquid separated by a centrifugal sedimentation machine, and then the solid particles were washed with a sufficient amount of pure water and dried at 110 ° C. to obtain a dry powder.

The obtained dry powder was dispersed in hydrochloric acid at room temperature of 1 mol / L, filtered, and then the solid particles were washed with a sufficient amount of pure water, filtered again, and dried at 100 ° C. overnight. After firing at 550 ° C. for 1 hour under air, it was treated with 30% steam at 600 ° C. for 2 hours.

The obtained powder was dispersed in hydrochloric acid at room temperature of 1 mol / L, filtered, and then the solid particles were washed with a sufficient amount of pure water and filtered again to obtain zeolite.

To 100 parts by weight of the obtained zeolite, 25 parts by weight of silica (manufactured by Nissan Chemical Industries, Ltd., (trade name) Snowtex N-30G), 5 parts by weight of cellulose, and 40 parts by weight of pure water were added and kneaded. Then, the kneaded product was made into a columnar molded body having a diameter of 1.5 mm and a length of 1.0 to 7.0 mm (average length of 3.5 mm). This was dried at 100 ° C. overnight. The dried molded product was fired at 600 ° C. for 2 hours under air flow to obtain a molded product.

5 g of the obtained MFI-type zeolite molded product was filled in a borosilicate glass tube having an inner diameter of 9.5 mm. Separately, 0.2 g of silver nitrate was dissolved in 25 ml of pure water to prepare a 0.05 mol / L silver nitrate aqueous solution. The circulation pump and the lower part of the glass tube were connected using a chemical-resistant polyolefin hose, and the silver nitrate aqueous solution was circulated for 2 hours in a dark place. After extracting all the silver nitrate aqueous solution and circulating 30 ml of pure water for 30 minutes, all the washing liquid was extracted and the pH was measured. Then, washing was repeated until the pH was within the range of 5 to 6. After washing, the zeolite was collected in a magnetic dish, heated to 110 ° C. at a heating rate of 10 ° C./min, and dried overnight. Subsequently, the temperature was raised to 550 ° C. at a heating rate of 2 ° C./min and calcined for 6 hours.

Table 1 shows the physical characteristics of the obtained silver-containing zeolite. The obtained zeolite was a 10-membered ring-pore zeolite having a skeleton structure of an MFI-type zeolite, had a silver content of 1.1 wt%, and had an average particle size of 25 nm measured using a TEM.

The difference spectrum of infrared absorption before and after adsorbing 2,4-dimethylquinoline on the obtained MFI-type silver-containing zeolite is shown in FIG. 1 (sample amount 51 mg), and the difference spectrum of infrared absorption before and after adsorbing pyridine. Is shown in FIG. 2 (sample amount 53 mg). The amount of B acid on the outer surface determined from the decrease in the peak derived from the OH of the zeolite B acid point of 3600 cm ^-1 in FIG. 1 was 3.3 μmol / g, and the pyridine adsorbed on the zeolite B acid point ^{of 1545 cm -1 in FIG.} The amount of B acid determined from the increase in the peak derived from is 0.06 mmol / g, and the outer surface B acid ratio was 5.4%.

Using the obtained molded product as a catalyst for producing aromatic hydrocarbons, aromatic hydrocarbons were produced under the above conditions, and aromatization was evaluated. The flow rate of the raw material gas was isobutane 2N ml / min, normal butene 5Nml / min, trans-2-butene 8Nml / min, 1-butene 15Nml / min, isobutene 3Nml / min, propane 7Nml / min, propylene 2Nml / min. .. Table 2 shows the conversion rate of C4 components, the yield of aromatic hydrocarbons, and the yield of benzene with respect to the reaction time. During the reaction time of 30 minutes to 48 hours, the C4 component conversion rate, the aromatic yield, and the benzene yield all showed high values. Further, even if the production of aromatic hydrocarbons and the regeneration cycle of the catalyst for producing aromatic hydrocarbons are repeated 30 times, it is possible to stably produce aromatic hydrocarbons and benzene, and the durability is excellent and stable. It was confirmed that reproduction was possible.

Example 2
The silver-unsupported MFI-type zeolite molded product obtained in Example 1 was silver-supported by an ion exchange method. The procedure was the same as in Example 1 except that the amount of silver nitrate was changed to 0.3 g. The silver content of the obtained molded product was 1.3 wt%, and the average particle size measured using TEM was 22 nm.

The difference spectrum of infrared absorption before and after adsorbing 2,4-dimethylquinoline on the obtained MFI-type silver-containing zeolite is shown in FIG. 1 (sample amount 57 mg), and the difference spectrum of infrared absorption before and after adsorbing pyridine. Is shown in FIG. 2 (sample amount 54 mg). The amount of B acid on the outer surface was 1.8 μmol / g, which was determined from the decrease in the peak derived from the OH of the zeolite B acid point ^{of 3600 cm -1} in FIG. 1, and was adsorbed on the zeolite B acid point ^{of 1545 cm -1 in FIG.} The amount of B acid determined from the increase in the peak derived from pyridine was 0.05 mmol / g, and the outer surface B acid ratio was 3.5%.

Using the obtained molded product as a catalyst for producing an aromatic hydrocarbon, an aromatic compound was produced under the above-mentioned conditions, and the aromatization was evaluated. The flow rate of the raw material gas was isobutane 2N ml / min, normal butene 5Nml / min, trans-2-butene 8Nml / min, 1-butene 15Nml / min, isobutene 3Nml / min, propane 7Nml / min, propylene 2Nml / min. .. Table 2 shows the conversion rate of C4 components, the yield of aromatic hydrocarbons, and the yield of benzene with respect to the reaction time. During the reaction time of 30 minutes to 48 hours, the C4 component conversion rate, the aromatic yield, and the benzene yield all showed high values. Further, even if the production of aromatic hydrocarbons and the regeneration cycle of the catalyst for producing aromatic hydrocarbons are repeated 30 times, it is possible to stably produce aromatic hydrocarbons and benzene, and the durability is excellent and stable. It was confirmed that reproduction was possible.

Example 3
The silver-unsupported MFI-type zeolite molded product obtained in Example 1 was silver-supported by an ion exchange method. The procedure was the same as in Example 1 except that the zeolite molded product was changed to 10 g, the amount of silver nitrate was changed to 1.0 g, and the amount of pure water was changed to 35 ml. The silver content of the obtained molded product was 1.5 wt%, and the average particle size measured using TEM was 24 nm.

The difference spectrum of infrared absorption before and after adsorbing 2,4-dimethylquinoline on the obtained MFI-type silver-containing zeolite is shown in FIG. 1 (sample amount 56 mg), and the difference spectrum of infrared absorption before and after adsorbing pyridine. Is shown in FIG. 2 (sample amount 56 mg). The amount of B acid on the outer surface was 4.1 μmol / g, which was determined from the decrease in the peak derived from the OH of the zeolite B acid point ^{of 3600 cm -1} in FIG. 1, and was adsorbed on the zeolite B acid point ^{of 1545 cm -1 in FIG.} The amount of B acid determined from the increase in the peak derived from pyridine was 0.04 mmol / g, and the outer surface B acid ratio was 9.6%.

Using the obtained molded product as a catalyst for producing an aromatic hydrocarbon, an aromatic compound was produced under the above-mentioned conditions, and the aromatic hydrocarbon was evaluated. The flow rate of the raw material gas was isobutane 2N ml / min, normal butene 5Nml / min, trans-2-butene 8Nml / min, 1-butene 15Nml / min, isobutene 3Nml / min, propane 7Nml / min, propylene 2Nml / min. .. Table 2 shows the conversion rate of C4 components, the yield of aromatic hydrocarbons, and the yield of benzene with respect to the reaction time. During the reaction time of 30 minutes to 48 hours, the C4 component conversion rate, the aromatic yield, and the benzene yield all showed high values. Further, even if the production of aromatic hydrocarbons and the regeneration cycle of the catalyst for producing aromatic hydrocarbons are repeated 30 times, it is possible to stably produce aromatic hydrocarbons and benzene, and the durability is excellent and stable. It was confirmed that reproduction was possible.

Comparative Example 1
Crystallization, washing, and drying of zeolite by autoclave were carried out in the same manner as in Example 1.
The obtained dry powder is calcined under air at 550 ° C., the obtained powder is dispersed in 1 mol / L hydrochloric acid at room temperature, filtered, and then the solid particles are washed with a sufficient amount of pure water and again. After filtration, it was dried at 100 ° C. overnight to obtain zeolite.

To 100 parts by weight of the obtained zeolite, 25 parts by weight of silica (manufactured by Nissan Chemical Industries, Ltd., (trade name) Snowtex N-30G), 5 parts by weight of cellulose, and 40 parts by weight of pure water were added and kneaded. Then, the kneaded product was made into a columnar molded body having a diameter of 1.5 mm and a length of 1.0 to 7.0 mm (average length of 3.5 mm). This was dried at 100 ° C. overnight. The dried molded product was fired at 600 ° C. for 2 hours under air flow to obtain a molded product.

The obtained MFI-type zeolite molded product was supported on silver by an ion exchange method. 0.3 g of silver nitrate was dissolved in 100 ml of pure water, 3 g of the above MFI-type zeolite was added to the aqueous solution, and the mixture was stirred at room temperature for 2 hours. After filtering with a Büchner funnel, 35 g of pure water was added, and the mixture was stirred in the same manner. After stirring with pure water a total of 3 times, the filtered zeolite was dried at 110 ° C. overnight and calcined at 550 ° C. for 6 hours.

Table 1 shows the physical characteristics of the obtained zeolite. The obtained zeolite was a 10-membered ring-pore zeolite having a skeleton structure of an MFI-type zeolite, had a silver content of 1.2 wt%, and had an average particle size of 20 nm measured using a TEM.

The difference spectrum of infrared absorption before and after adsorbing 2,4-dimethylquinoline on the obtained zeolite is shown in FIG. 1 (sample amount 50 mg), and the difference spectrum of infrared absorption before and after adsorbing pyridine is shown in FIG. Shown (sample volume 51 mg). The amount of B acid on the outer surface determined from the decrease in the peak derived from the OH of the zeolite B acid point of 3600 cm ^-1 in FIG. 1 was 10.1 μmol / g, and the pyridine adsorbed on the zeolite B acid point ^{of 1545 cm -1 in FIG.} The amount of B acid determined from the increase in the peak derived from is 0.10 mmol / g, and the outer surface B acid ratio was 10.1%.

Using the obtained molded product as a catalyst for producing aromatic hydrocarbons, aromatic hydrocarbons were produced under the above conditions, and aromatization was evaluated. The flow rate of the raw material gas was isobutane 2N ml / min, normal butene 5Nml / min, trans-2-butene 8Nml / min, 1-butene 15Nml / min, isobutene 3Nml / min, propane 7Nml / min, propylene 2Nml / min. .. Table 2 shows the conversion rate of C4 components, the yield of aromatic hydrocarbons, and the yield of benzene with respect to the reaction time. During the reaction time of 30 minutes to 48 hours, the C4 component conversion rate, aromatic yield, and benzene yield were all low, and the catalytic performance was inferior. Further, when the production of aromatic hydrocarbons and the regeneration cycle of the catalyst for producing aromatic hydrocarbons were repeated, it was confirmed that the performance was significantly deteriorated at the 11th time, and the durability and reproducibility were inferior.

Comparative Example 2
The difference spectrum of infrared absorption before and after adsorbing 2,4-dimethylquinoline on the silver-unsupported MFI-type zeolite molded product obtained in Example 1 is shown in FIG. 1 (sample amount 51 mg). The difference spectrum of infrared absorption before and after adsorbing pyridine is shown in FIG. 2 (sample amount 59 mg). The amount of B acid on the outer surface determined from the decrease in the peak derived from the OH of the zeolite B acid point of 3600 cm ^-1 in FIG. 1 was 3.0 μmol / g, and the pyridine adsorbed on the zeolite B acid point ^{of 1545 cm -1 in FIG.} The amount of B acid determined from the increase in the peak derived from is 0.12 mmol / g, and the outer surface B acid ratio was 2.5%. The average particle size measured using TEM was 26 nm.

Using this molded product as a catalyst, aromatic hydrocarbons were produced under the above conditions, and aromaticization was evaluated. The flow rate of the raw material gas was isobutane 2N ml / min, normal butene 5Nml / min, trans-2-butene 8Nml / min, 1-butene 15Nml / min, isobutene 3Nml / min, propane 7Nml / min, propylene 2Nml / min. .. Table 2 shows the conversion rate of C4 components, the yield of aromatic hydrocarbons, and the yield of benzene with respect to the reaction time. During the reaction time of 30 minutes to 48 hours, the C4 component conversion rate, aromatic yield, and benzene yield were all low, and the catalytic performance was inferior.

Comparative Example 3
Crystallization, washing, and drying of zeolite by autoclave were carried out in the same manner as in Example 1.

The obtained dry powder was dispersed in hydrochloric acid at room temperature of 1 mol / L, filtered, and then the solid particles were washed with a sufficient amount of pure water, filtered again, and dried at 100 ° C. overnight. After firing at 550 ° C. for 1 hour under air, it was treated with 30% steam at 600 ° C. for 2 hours.

The obtained powder was dispersed in hydrochloric acid at room temperature of 1 mol / L, filtered, and then the solid particles were washed with a sufficient amount of pure water and filtered again to obtain zeolite.

To 100 parts by weight of the obtained zeolite, 25 parts by weight of silica (manufactured by Nissan Chemical Industries, Ltd., (trade name) Snowtex N-30G), 5 parts by weight of cellulose, and 40 parts by weight of pure water were added and kneaded. Then, the kneaded product was made into a columnar molded body having a diameter of 1.5 mm and a length of 1.0 to 7.0 mm (average length of 3.5 mm). This was dried at 100 ° C. overnight. The dried molded product was fired at 600 ° C. for 2 hours under air flow to obtain a molded product.

The obtained MFI-type zeolite molded product was supported on silver by an impregnation method. 1.0 g of silver nitrate was dissolved in 7 ml of pure water, 15 g of the above MFI-type zeolite was added to the aqueous solution, and the mixture was immersed at room temperature for 5 minutes. The zeolite was then dried at 110 ° C. overnight and calcined at 550 ° C. for 6 hours.

Table 1 shows the physical characteristics of the obtained zeolite. The obtained zeolite was a 10-membered ring-pore zeolite having a skeleton structure of an MFI-type zeolite, had a silver content of 3.8 wt%, and had an average particle size of 24 nm measured using a TEM.

The difference spectrum of infrared absorption before and after adsorbing 2,4-dimethylquinoline on the obtained zeolite is shown in FIG. 1 (sample amount 49 mg), and the difference spectrum of infrared absorption before and after adsorbing pyridine is shown in FIG. Shown (sample volume 48 mg). The amount of B acid on the outer surface determined from the decrease in the peak derived from the OH of the zeolite B acid point of 3600 cm ^-1 in FIG. 1 was 8.9 μmol / g, and the pyridine adsorbed on the zeolite B acid point ^{of 1545 cm -1 in FIG.} The amount of B acid determined from the increase in the peak derived from is 0.06 mmol / g, and the outer surface B acid ratio was 13.8%.

Using the obtained molded product as a catalyst for producing aromatic hydrocarbons, aromatic hydrocarbons were produced under the above conditions, and aromatization was evaluated. The flow rate of the raw material gas was isobutane 2N ml / min, normal butene 5Nml / min, trans-2-butene 8Nml / min, 1-butene 15Nml / min, isobutene 3Nml / min, propane 7Nml / min, propylene 2Nml / min. .. Table 2 shows the conversion rate of C4 components, the yield of aromatic hydrocarbons, and the yield of benzene with respect to the reaction time. During the reaction time of 30 minutes to 48 hours, the C4 component conversion rate, aromatic yield, and benzene yield were all low, and the catalytic performance was inferior. Further, when the production of aromatic hydrocarbons and the regeneration cycle of the catalyst for producing aromatic hydrocarbons were repeated, the yields of aromatic hydrocarbons and benzene were lower than those of any of the examples up to the second time, and the catalyst for producing aromatic hydrocarbons. Confirmed that it is inferior.

Example 4
The zeolite obtained in Example 1 after washing with hydrochloric acid was supported on silver by an impregnation method. 0.2 g of silver nitrate was dissolved in 100 ml of pure water, 5 g of the above-mentioned zeolite was added to the aqueous solution, and the solution was stirred at room temperature for 4 hours. After filtration, washing with 150 mL of pure water and filtration were repeated three times, and then the zeolite was dried at 110 ° C. overnight and calcined at 550 ° C. for 4 hours.

Table 3 shows the physical characteristics of the obtained zeolite. The obtained zeolite was a 10-membered ring-pore zeolite having a skeleton structure of MFI-type zeolite, had a silver content of 0.8 wt%, and had an average particle size of 21 nm measured using TEM.

The difference spectrum of infrared absorption before and after adsorbing 2,4-dimethylquinoline on the obtained MFI-type silver-containing zeolite is shown in FIG. 3 (sample amount 57 mg), and the difference spectrum of infrared absorption before and after adsorbing pyridine. Is shown in FIG. 4 (sample amount 49 mg). The amount of B acid on the outer surface was 8.8 μmol / g, which was determined from the decrease in the peak derived from the OH of the zeolite B acid point ^{of 3600 cm -1} in FIG. 3, and was adsorbed on the zeolite B acid point ^{of 1545 cm -1 in FIG.} The amount of B acid determined from the increase in the peak derived from pyridine was 0.09 mmol / g, and the outer surface B acid ratio was 9.8%.

To 100 parts by weight of the obtained silver-containing zeolite, 25 parts by weight of silica (manufactured by Nissan Chemical Industries, Ltd., (trade name) Snowtex N-30G), 5 parts by weight of cellulose, and 40 parts by weight of pure water were added and kneaded. Then, the kneaded product was made into a columnar molded body having a diameter of 1.5 mm and a length of 1.0 to 7.0 mm (average length of 3.5 mm). This was dried at 100 ° C. overnight. The dried molded product was fired at 600 ° C. for 2 hours under air flow to obtain a molded product.

Using the obtained molded product as a catalyst for producing an aromatic hydrocarbon, an aromatic compound was produced under the above-mentioned conditions, and the aromatic hydrocarbon was evaluated. The flow rate of the raw material gas was isobutane 2N ml / min, normal butene 5Nml / min, trans-2-butene 8Nml / min, 1-butene 15Nml / min, isobutene 3Nml / min, propane 7Nml / min, propylene 2Nml / min. .. Table 4 shows the conversion rate of C4 components, the yield of aromatic hydrocarbons, and the yield of benzene with respect to the reaction time. During the reaction time of 30 minutes to 48 hours, the C4 component conversion rate, the aromatic yield, and the benzene yield all showed high values. Further, even if the production of aromatic hydrocarbons and the regeneration cycle of the catalyst for producing aromatic hydrocarbons are repeated 30 times, it is possible to stably produce aromatic hydrocarbons and benzene, and the durability is excellent and stable. It was confirmed that playback was possible.

Example 5
The zeolite obtained in Example 1 after washing with hydrochloric acid was supported on silver by an impregnation method. 0.2 g of silver nitrate was dissolved in 100 ml of pure water, 5 g of the above-mentioned zeolite was added to the aqueous solution, and the solution was stirred at room temperature for 4 hours. The silver-containing zeolite powder obtained after filtration was added to an aqueous solution prepared by dissolving 0.2 g of silver nitrate in 100 ml of pure water, and the solution was stirred at room temperature for 4 hours. After filtration, washing with 150 mL of pure water and filtration were repeated three times, and then the zeolite was dried at 110 ° C. overnight and calcined at 550 ° C. for 4 hours.

Table 3 shows the physical characteristics of the obtained zeolite. The obtained zeolite was a 10-membered ring-pore zeolite having a skeleton structure of an MFI-type zeolite, had a silver content of 1.6 wt%, and had an average particle size of 24 nm measured using a TEM.

The difference spectrum of infrared absorption before and after adsorbing 2,4-dimethylquinoline on the obtained MFI-type silver-containing zeolite is shown in FIG. 3 (sample amount 51 mg), and the difference spectrum of infrared absorption before and after adsorbing pyridine. Is shown in FIG. 4 (sample amount 48 mg). The amount of B acid on the outer surface was 4.5 μmol / g, which was determined from the decrease in the peak derived from the OH of the zeolite B acid point ^{of 3600 cm -1} in FIG. 3, and was adsorbed on the zeolite B acid point ^{of 1545 cm -1 in FIG.} The amount of B acid determined from the increase in the peak derived from pyridine was 0.05 mmol / g, and the outer surface B acid ratio was 9.6%.

To 100 parts by weight of the obtained silver-containing MFI-type zeolite, 25 parts by weight of silica (manufactured by Nissan Chemical Industries, Ltd. (trade name) Snowtex N-30G), 5 parts by weight of cellulose, and 40 parts by weight of pure water are added and kneaded. did. Then, the kneaded product was made into a columnar molded body having a diameter of 1.5 mm and a length of 1.0 to 7.0 mm (average length of 3.4 mm). This was dried at 100 ° C. overnight. The dried molded product was fired at 600 ° C. for 2 hours under air flow to obtain a molded product.

Using the obtained molded product as a catalyst for producing an aromatic hydrocarbon, an aromatic compound was produced under the above-mentioned conditions, and the aromatic hydrocarbon was evaluated. The flow rate of the raw material gas was isobutane 2N ml / min, normal butene 5Nml / min, trans-2-butene 8Nml / min, 1-butene 15Nml / min, isobutene 3Nml / min, propane 7Nml / min, propylene 2Nml / min. .. Table 4 shows the conversion rate of C4 components, the yield of aromatic hydrocarbons, and the yield of benzene with respect to the reaction time. During the reaction time of 30 minutes to 48 hours, the C4 component conversion rate, the aromatic yield, and the benzene yield all showed high values. Further, even if the production of aromatic hydrocarbons and the regeneration cycle of the catalyst for producing aromatic hydrocarbons are repeated 30 times, it is possible to stably produce aromatic hydrocarbons and benzene, and the durability is excellent and stable. It was confirmed that reproduction was possible.

The novel silver-containing zeolite having a trace amount of B acid and silver on the outer surface of the present invention has specific stability during conversion / isomerization reaction of hydrocarbon raw materials such as lower olefins, especially during aromatization. It exhibits efficiency and durability, and its industrial value as a catalyst is extremely high.

Claims (9)

A silver-containing zeolite containing silver and satisfying the following characteristics (i) to (iv).
(I) The average particle size is 100 nm or less.
(Ii) 10-membered ring pore zeolite.
(Iii) The silver content is 0.05 to 3 wt%.
(Iv) The amount of Bronsted acid on the outer surface is 0.1 to 10.0 μmol / g. The zeolite according to claim 1, wherein the 10-membered ring-pore zeolite is an MFI type or a MEL type. The zeolite according to claim 1 or 2, wherein (v) the amount of Bronsted acid is 0.01 to 1.0 mmol / g. A catalyst for producing an aromatic hydrocarbon, which comprises the zeolite according to any one of claims 1 to 3. The catalyst for producing an aromatic hydrocarbon according to claim 4, further comprising silica. The catalyst for producing an aromatic hydrocarbon according to claim 4 or 5, wherein the molded product has a cylindrical shape or a cylindrical shape. The catalyst for producing an aromatic hydrocarbon according to claim 6, wherein the molded product has a cylindrical shape having a diameter of 1 to 10 mm. The catalyst for producing an aromatic compound according to claim 6, wherein the molded product has a cylindrical shape having a thickness of 0.5 to 5.0 mm. An aromatic characterized by contacting a raw material containing at least 70% by mass of a non-aromatic hydrocarbon having 4 to 6 carbon atoms in the presence of the aromatic hydrocarbon production catalyst according to any one of claims 4 to 8. Method for producing hydrocarbons.

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