JPH11169719A - Aluminum-beta zeolite catalyst for alkylation of aromatic compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a β zeolite exhibiting excellent deterioration resistance without spoiling essential characteristics of zeolite being high activity and high selectivity in comparison with conventional zeolite in alkylation reaction of arom. hydrocarbons. SOLUTION: A β zeolite catalyst having Al ions out of the zeolite crystal lattice and pref., a β zeolite catalyst wherein the aluminum index (V) of Al ions existing out of the zeolite crystal lattice is 1<=V<=3 and the amt. of the Al ions existing out of the zeolite crystal lattice is at least 0.15 mmol per zeolite dry wt. and the amt. of the Al ions to the total amt. of protons and the Al ions (Al ion ratio) is at least 0.4 by molar ratio in relation to protons bonded to the zeolite crystal lattice, is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalyst used for a reaction for alkylating an aromatic hydrocarbon in order to produce an alkylbenzene useful as a raw material for various polymers.

[0002]

BACKGROUND OF THE INVENTION Alkylation of aromatic hydrocarbons has been carried out industrially using Friedel-craft type catalysts such as aluminum chloride and boron trifluoride. However, these materials are highly corrosive and have environmental problems when disposed. As a result of research on non-corrosive solid catalysts replacing Friedel-Crafts catalysts, various zeolite catalysts have been proposed.

US Pat. No. 3,641,177 discloses steam-stabilized HY zeolites or HY zeolites partially exchanged with rare earths as catalysts for the alkylation reaction of benzene with olefins. ing. U.S. Patent No. 3,
751,504 and 3,751,506 show ZSM-5 zeolite as a catalyst for the alkylation and transalkylation reactions of aromatic hydrocarbons in the gas phase.

[0004] US Pat. No. 5,334,795 discloses MCM-2 as a catalyst for producing ethylbenzene by an alkylation reaction with benzene and ethylene.
2 is described. JP-A-3-181424 discloses β zeolite as a catalyst for an alkylation reaction of an aromatic hydrocarbon with an olefin and a transalkylation reaction of an aromatic hydrocarbon in a liquid phase. Here, it is described that β zeolite has a feature of providing a monoalkylated product in a high yield over a long period of time as compared with other zeolite catalysts.

[0005] As a catalyst for the alkylation reaction of aromatic hydrocarbons, β zeolite is a catalyst having higher activity, higher selectivity and degradation resistance than other zeolite catalysts. However, industrially, it is important to increase the cycle of regeneration or replacement of the catalyst to further improve the productivity.
Furthermore, if the amount of the catalyst used can be reduced, there is an advantage that the equipment can be made more compact. For that purpose, it has been necessary to develop a catalyst which exhibits higher activity and selectivity while maintaining high activity and selectivity, and which has higher degradation resistance.

[0006] EP-A-507,761 describes β zeolite ion-exchanged with La as an aromatic alkylation catalyst. JP-A-7-53415 describes a β zeolite modified by ion exchange of an alkali metal, an alkaline earth metal or Ni as a catalyst for producing cumene from benzene and propylene. However, these catalysts have been developed for the purpose of improving the selectivity, and a remarkable decrease in activity is expected especially when ion exchange is performed with an alkali metal. Therefore, these methods cannot be expected to improve deterioration resistance while maintaining high catalytic activity.

JP-A-3-181424 uses β zeolite as a catalyst for an alkylation reaction and a transalkylation reaction in a liquid phase. Here, ion exchange by groups IA, IIA, IIIA or transition metals of the periodic table is shown, with at least 80% of the cation points being occupied by hydrogen ions and / or rare earth metals. Is preferred. Also, JP-A-8-1
JP-A-03658 describes a β zeolite modified by introducing an alkali metal and / or an alkaline earth metal by an ion exchange method as a catalyst used in the alkylation or transalkylation reaction of an aromatic compound. .
Although these patents are expected to improve deterioration resistance as an effect, when ion exchange is performed with an alkali metal or the like, a reduction in activity is expected.

US Pat. No. 5,227,558 describes a process for alkylating aromatics using a steam-modified β zeolite catalyst. However,
A in the zeolite crystal lattice to remove aluminum by steam
There is a problem that l decreases and the catalyst activity also decreases. As described above, conventionally, while maintaining the high activity and selectivity inherent in β zeolite,
There was no technique for exhibiting high deterioration resistance.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a β zeolite having high activity and high selectivity and exhibiting excellent deterioration resistance without impairing the intrinsic properties of β zeolite. .

[0010]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, have exerted high degradation resistance while maintaining the high activity and selectivity inherent in β zeolite. An Al-β zeolite catalyst having Al ions outside the zeolite crystal lattice was found, and the present invention was completed.

That is, the present invention is as follows. 1) β zeolite catalyst having Al ions outside the zeolite crystal lattice, used for aromatic alkylation. 2) The β zeolite catalyst as described in 1 above, wherein the Al ion has an aluminum index (V) defined by the following formula (1) and 1 ≦ V ≦ 3.

Aluminum index (V) = (L−H−N) / (A−L) (1) (where A is the amount of Al in zeolite (mmol / g),
N is the amount of Na (mmol / g) in the zeolite;
l and metals other than Na as 0.01 mm
1 / g or more, H is the value obtained by adding the amounts of these metals to the amount of Na, and H is the amount of protons in the zeolite (mmol /
g), L is the amount of Al in the zeolite lattice (mmol /
g). 3) Al ion is 0.15 per dry weight of zeolite
The amount of Al ions relative to the total amount of protons and Al ions (hereinafter, referred to as Al ion ratio) is at least 0.4 in terms of molar ratio with respect to the cations bonded to the zeolite crystal lattice at the same time as the presence of at least mmol. 3. The β zeolite catalyst according to the above 1 or 2, wherein

Hereinafter, the present invention will be described in detail. The activity referred to in the present invention is the conversion of an olefin when an alkylation reaction of an aromatic hydrocarbon is performed under the same conditions, and the selectivity is the ratio of a monoalkylated product in a product.
Zeolite has a structure of a condensed acid of silicate, and has a SiO ₄ tetrahedron centered on Si and an A in which Si is replaced by Al.
to lO ₄ tetrahedral basic structure, forming a crystal structure sharing the O 2 single tetrahedral. For beta zeolite,
These basic structures have a lattice structure having cavities (pores) formed by connecting 12 of them. The zeolite crystal lattice referred to in the present invention refers to the above-mentioned structure, and Al forming the crystal lattice is Al within the crystal lattice (Al within the lattice).
The other Al, including those desorbed from the lattice, is Al outside the crystal lattice (Al outside the lattice). In addition, since the tetravalent Si is substituted with trivalent Al, the crystal structure has an anion site corresponding to the amount of Al in the lattice, and a cation acts on the anion site, The zeolite as a whole is electrically neutral. A of the present invention
The l-ion is present in association with the anion site of the zeolite crystal lattice.

Here, the aluminum index (V) defined by the above equation (1) will be described. In this formula, A is the total Al content (mm) in the zeolite containing all aluminum metal ions.
ol / g), which is the total value of Al in the lattice and Al in the lattice. N is the amount of Na in the zeolite (mmol /
g). When metals other than Al and Na exist as cations in an amount of 0.01 mmol / g or more, a value obtained by adding the amounts of these metals to the amount of Na is used as N. In addition, these values are calculated based on the content obtained by the fluorescent X-ray.
H is the amount of protons in the zeolite (mmol / g), which the present inventors have reported in the journal of the Chemical Society of Japan, 1994 (8), p6.
According to the method for measuring the amount of acid shown in 90, the calculation is performed from the pH value of the filtrate and the washing solution after ion exchange. L is the amount of Al in the lattice of the zeolite (mmol / g), and is the amount of cations determined according to the above-mentioned literature.

In the present invention, the amount of Al ions is determined by subtracting L (mmol / g), which is the amount of Al in the zeolite lattice, from A (mmol / g), which is the amount of Al in the zeolite. . Here, a method for measuring the amount of protons and the amount of Al in the lattice will be described in more detail. The amount of proton was 1.5 g of zeolite, 4.3 mol / dm.
^{Then, the} mixture was added to 25 cm ³ of the aqueous solution of NaCl of Example ³ and stirred at 2 ° C. for 10 minutes to perform ion exchange. Then, filter, 50cm
^After washing with ion-exchanged water of No. ³ , the pH of the mixture of the filtrate and the washing water was measured with a pH meter. For the amount of Al in the lattice, 1.5 g of zeolite is added to 25 cm ³ of a 4.3 mol / dm ³ aqueous solution of NaCl, and the mixture is stirred at 80 ° C. for 360 minutes to perform ion exchange. After that, it is filtered and 50c
After washing with m ³ deionized water, the mixture of the filtrate and the washing water is titrated with an aqueous NaOH solution. The neutralization titer is defined as the amount of cations. The amount of cations obtained here indicates the amount of Al in the lattice of the zeolite.
The above values are values per zeolite dry weight, and the weight reduction rate when the temperature was raised to 300 ° C., determined by TGA, was defined as the water content, and the value was converted based on the value.

Al is known as a metal exhibiting Lewis acidity. Therefore, it is considered that the compound exhibits activity in the alkylation reaction of aromatic hydrocarbons. However, in the patent for modifying the zeolite catalyst by dealumination, dealuminated Al inhibits the reaction. Therefore, in general, ion exchange is repeated after dealumination to remove the detached Al.

Al, which can act as an active factor in the alkylation of aromatic hydrocarbons, essentially hinders the reaction. As a cause of this, the present inventors have paid attention to the existence state of Al existing outside the zeolite crystal lattice.
That is, when Al is present as a certain mass in the pores of the zeolite, it inhibits the diffusion of the substance in the pores, and since the effect is larger than the effect as a reaction activator, it seems that the reaction is inhibited. . In other words, it was considered that the presence of Al without inhibiting the diffusion of the substance in the pores would act as an activator. For that purpose, it is necessary that Al is dispersed and present as each ion.
Was considered as a reaction activating factor, it was considered that Lewis acid, which has a lower acid strength than protons, which is a Bronsted acid, would improve the deterioration resistance of the catalyst.

Here, the above equation (1) represents the average valence of Al existing outside the crystal lattice of zeolite.
Therefore, when V ≧ 1, Al existing outside the zeolite crystal lattice is considered to exist as ions on average. Therefore, Al acts as a catalyst without hindering substance diffusion in the zeolite pores. On the other hand, V <
In the case of 1, some of Al are present as being dispersed as ions, but there are also some that become metal agglomerates and inhibit diffusion in the pores, and the effect of the present invention is not sufficiently exerted.

The amount of Al ions existing outside the zeolite crystal lattice is preferably at least 0.15 mmol, more preferably 0.20 mmol per dry weight of zeolite.
1 or more. At the same time, with respect to the cations bonded to the crystal lattice of the zeolite, the amount of Al ions is preferably at least 0.4, more preferably at least 0.5, in terms of molar ratio, based on the total amount of protons and Al ions. is there. When the amount of Al ions is less than 0.15 mmol per zeolite weight, depending on the SiO ₂ / Al ₂ O _{3 of} the zeolite, sufficient catalytic activity may not be obtained, or the amount of protons may increase, resulting in a sufficient deterioration resistance. May not be improved. When the amount of Al ions is less than 0.4 in molar ratio with respect to the total amount of protons and Al ions, the amount of protons is large,
In some cases, the deterioration resistance is not sufficiently improved.

In the present invention, the type and valence of Al ions are not particularly limited. For example, Al
Various states such as (OH) ₂ ⁺ , AlO ⁺ , Al (OH) ²⁺ , and Al ³⁺ can be taken. However, from the viewpoint that the diffusion in the zeolite pores is not hindered, ions having a small ionic radius are more preferable. Beta zeolite is a known synthetic crystalline aluminosilicate first described in U.S. Pat. No. 3,308,069 and has the following composition: [(x / n) M (1 + 0.1- x) TEA] AlO _2.
ySiO ₂ · wH ₂ O (where x <1 and 5 <y <100, w is up to 4 depending on the dehydration conditions and the type of metal cation, and TEA is tetraethylammonium.) β in the present invention Zeolites include those obtained by removing organic ammonium salts by calcination or the like, in addition to those having the above composition. Reference is made to the patent for the preparation and properties of this zeolite. The synthesized β zeolite is identified by the d-value of X-ray diffraction described in US Pat. No. 3,308,069.

In the above β zeolite, M is
These Na ions are subjected to cation exchange,
By replacing all or part of the ions with Al ions
Bright Al-β zeolite can be obtained. How to exchange
The law is not particularly limited, but examples include:
Β zeolite after synthesis and calcination using an aqueous solution of Al salt
There is a method of ion exchange directly. This method uses ion
During the exchange, Al in the zeolite crystal lattice
As a result, the active sites are hardly reduced, and thus the Al-
Suitable for obtaining beta zeolite. Al salts are special
, But not limited to_Two(SO_Four)_ThreeAnd Al
(NO_Three)_ThreeAl salt whose aqueous solution is acidic
Is more preferred. On the other hand, β zeolite is
Al in the crystal lattice is thermodynamically unstable compared to
And easy to desorb, SiO_Two/ Al _TwoO_ThreeIs 50 or less
If a certain amount of β zeolite is used, the treatment with an appropriate concentration of acid
It is found that the Al-β zeolite of the present invention can be obtained
come. In this case, Al desorbed from the zeolite crystal lattice
Are cation exchanged. The acid used here is not particularly limited.
No, but H_TwoSO_Four, HNO_ThreeDilute solutions of mineral acids such as
But more suitable.

Japanese Unexamined Patent Publication (Kokai) No. 4-187647 describes an aromatic conversion method and a catalyst thereof. However, it is specified that the amount of Na in the β zeolite used herein is less than 0.04% by weight as Na ₂ O. doing. In the present invention, although the amount of Na is not particularly limited, it is clear that the presence of Na affects the reaction, and the smaller the amount, the more preferable. Also, the amount of metals other than Na present as cations is not specifically defined.

When the Al-β zeolite of the present invention is used for an aromatic alkylation reaction, pure zeolite may be used as a catalyst, but generally, zeolite powder is used.
Inorganic oxides such as alumina, silica and clay are used alone or in combination as a binder. The catalyst usually contains 1
It contains 0-90%, preferably 60-80% zeolite. The catalyst can be molded and used by a commonly used method such as tablet molding or extrusion molding. At this time, in order to facilitate the mass transfer in the molded body and not to decrease the reaction activity as a result, a special shape that increases the surface area can be used.

The aromatic hydrocarbon which can be alkylated using the Al-β zeolite of the present invention as a catalyst is, for example, benzene, toluene and xylene, and a mixture thereof. The most preferred aromatic hydrocarbon is benzene. The olefin used for the alkyl reaction has 2 carbon atoms.
To 4, for example, ethylene, propylene,
-Dilute ethylene containing butenes and mixtures thereof, methane, ethane, hydrogen and the like. Most preferred olefins are ethylene and dilute ethylene. Usually, in order to prevent the catalytic activity from being reduced by the influence of the raw materials, a diene, a nitrogen compound, a sulfur compound, water and the like which may be present in these feed materials are removed and used in the reaction. The reaction products obtained by the alkylation reaction include, for example, ethylbenzene by the reaction of benzene and ethylene, and cumene by benzene and propylene.

The reaction using the Al-β zeolite of the present invention as a catalyst is carried out in a gas phase, a liquid phase or a gas-liquid mixed phase. More preferred here are a gas-liquid mixed phase and a liquid phase. Examples of the method for performing the reaction include a method using an autoclave with a stirrer in batch, a method using a fixed-bed reactor performed in an upflow or downflow method, or a method using a fluidized-bed reactor. As the reaction conditions, a temperature of 120
To 300 ° C., the pressure is 10 to 50 atm, and the supply rate of the reaction raw material is freely selected from the range of 0.1 to 200 hr ⁻¹ .

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to examples. In addition, the evaluation method of the synthesis | combination of (beta) zeolite and an alkylation reaction is as follows. [Synthesis of β zeolite] Two kinds of β zeolite powder samples were synthesized by the following method.

10% of tetraethylammonium hydroxide
170 g of an aqueous solution, 4.5 g of sodium hydroxide, and a predetermined amount of sodium aluminate NaAlO ₂ are added to 150 g of ion-exchanged water and dissolved by heating to 80 ° C. To the solution obtained in this manner, a predetermined amount of fused silica, nip seal (NV-3, manufactured by Nippon Silica Kogyo Co., Ltd.) and 7 g of β zeolite as seed crystals were added, and the mixture was stirred with a homogenizer at 5000 rpm for 45 minutes. The mixture is then
When placed in a 00 milliliter autoclave and left at 150 ° C. for 10 days without stirring, a large amount of crystalline material was formed. This material was filtered, washed, and dried at 120 ° C. for 24 hours to obtain a crystalline powder.

Next, this powder was gradually heated to 350 to 550 ° C. and finally calcined at 550 ° C. for 5 hours. The powder after calcination was identified as β zeolite by X-ray diffraction. The composition analysis of the powder was determined using fluorescent X-rays. Table 1 shows, for each sample, the amounts of sodium aluminate and fused silica used in the synthesis, and SiO ₂ / Al ₂ determined by X-ray fluorescence.
O ₃ is shown.

[0029]

[Table 1]

[Evaluation method of alkylation reaction] The alkylation reaction was evaluated under the following conditions. The sample powder is compression molded using a tablet molding machine, pulverized, and classified to 8 to 14 m.
The molded catalyst of esh was obtained. Inner diameter 20mm, length 800m
m, a stainless steel reaction tube provided with a 300 mm heat medium jacket for residual heat was used as a reactor. A pressure control valve was provided at the outlet of the reaction section, and a product liquid extracting valve was provided before the pressure control valve. In this reactor, 3 molded catalysts were added.
0 g was charged. The filling of the catalyst is performed from a position 200 mm from the boundary between the jacket portion and the reaction portion, and above and below the catalyst layer,
Dickson packing made of stainless steel of 3 mmφ was filled. Benzene was supplied at a supply rate of 4.4 mol / hr from an inlet on the jacket side of the reactor. The pressure in the reactor was adjusted to 14 kg / cm ² G by adjusting the pressure control valve at the outlet of the reactor, and the inside of the system was completely sealed. Thereafter, a heat medium of 128 ° C. is circulated through the residual heat jacket, and the temperature of the catalyst portion is reduced to 125 ° C.
° C. Thereafter, just before the entrance of the reactor, ethylene was supplied to benzene at a supply rate of 1.5 mol / hr to carry out the reaction. Under the above conditions, the reaction was carried out in an upflow mode and a downflow mode by exchanging the top and bottom of the reactor.

The composition of the recovered product liquid was analyzed by gas chromatography, and the selectivity of ethylbenzene and the conversion of ethylene were calculated. In addition, as an index of deterioration resistance, the ethylene conversion is represented by the time from when the temperature measured in the middle part of the catalyst layer reaches the maximum to when it decreases by 1%. It is determined that the longer the time is, the higher the deterioration resistance of the catalyst is.

[0032]

Example 1 [Ion exchange of β zeolite] Using sample 1 shown in Table 1, ion exchange was carried out by the following method. 85
g of Al (NO ₃ ) ₃ .9H ₂ O was dissolved in 450 ml of ion-exchanged water, and the solution was heated to 60 ° C.
50 g of β zeolite powder was added to the solution, and ion exchange was performed at 60 ° C. for 3 hours with stirring. After the exchange, the mixture was filtered and washed with ion-exchanged water until the washing liquid became neutral. Thereafter, drying was performed at 120 ° C. overnight, and Al-β
A zeolite was obtained.

The obtained Al-β zeolite was evaluated by the method shown in the present invention. Table 2 shows the results. [Evaluation of alkylation reaction] A reactor was set up so that the jacket portion was at the bottom, and the reaction was carried out in an upflow manner. When the reactor was filled with the catalyst, the catalyst layer was 210 mm. The highest temperature reached in the catalyst layer is 21
9 ° C., at which point the ethylene conversion was 9
It was 8.4%. Table 2 shows the ethylbenzene selectivity and the degradation resistance index.

[0034]

Example 2 [Ion Exchange of β Zeolite] Using Sample 2 shown in Table 1, ion exchange was carried out in the same manner as in Example 1. The obtained Al-β zeolite was evaluated by the method shown in the present invention. Table 2 shows the results.

[Evaluation of alkylation reaction] Using this zeolite, the reaction was evaluated in the same manner as in Example 1. When the reactor was filled with the catalyst, the catalyst layer was 207 mm. The highest temperature reached in the catalyst layer is 21
8 ° C., at which point the ethylene conversion was 9
It was 8.1%. Table 2 shows the ethylbenzene selectivity and the degradation resistance index.

[0036]

Example 3 [Evaluation of alkylation reaction] A reactor was set up so that the jacket portion was at the top, and the reaction was carried out in the downflow method using the same zeolite as in Example 2. When the reactor was filled with the catalyst, the catalyst layer was 212 mm. The highest temperature reached in the catalyst layer is 228 ° C. in the middle, and the ethylene conversion at that time is 98.9%
Met. Table 2 shows the ethylbenzene selectivity and the degradation resistance index.

[0037]

Example 4 [Ion Exchange of β Zeolite] Using Sample 2 shown in Table 1, ion exchange was carried out by the following method. 45
0 liter of a 0.15N aqueous nitric acid solution was heated to 60 ° C. 50 g of β zeolite powder was added to the solution,
Stir at 0 ° C. for 3 hours. Thereafter, the mixture was filtered, washed with ion-exchanged water until the washing liquid became neutral, and dried at 120 ° C. overnight. Using the obtained β zeolite, the above treatment was performed again to obtain a dry powder.

The obtained Al-β zeolite was evaluated by the method shown in the present invention. Table 2 shows the results. [Evaluation of alkylation reaction] The reaction was evaluated in the same manner as in Example 1 using this zeolite. When the reactor was filled with the catalyst, the catalyst layer was 210 mm. The highest temperature reached in the catalyst layer was 222 ° C. in the middle, and the ethylene conversion at that time was 98.4%.
Table 2 shows the ethylbenzene selectivity and the degradation resistance index.

From the aluminum index of the catalyst of this example, it is considered that Al outside the zeolite crystal lattice exists on average as Al ions. However, the amount is small and the proportion of Al ions is also low. Therefore, although the deterioration resistance was improved, the degree of the deterioration was lower than that of the other examples.

[0040]

Comparative Example 1 [Ion Exchange of β Zeolite] Using Sample 1 shown in Table 1, ion exchange was carried out by the following method. 12
0 g of NH ₄ Cl was dissolved in 450 ml of ion-exchanged water, and the temperature was raised to 60 ° C. 50 g of β-zeolite powder was added to the solution, and ion exchange was performed at 60 ° C. for 4 hours with stirring. After the exchange, the mixture was filtered, washed with deionized water, and dried at 120 ° C. overnight. After a while, 5
Calcination at 00 ° C. for 3 hours.

The obtained β zeolite was evaluated by the method shown in the present invention. Table 2 shows the results. There is no Al ion, which is different from the β zeolite of the present invention. [Evaluation of alkylation reaction] The reaction was evaluated in the same manner as in Example 1 using this zeolite. When the reactor was filled with the catalyst, the catalyst layer was 211 mm. The highest temperature reached in the catalyst layer was 223 ° C. in the middle, and the ethylene conversion at that time was 98.7%.
Table 2 shows the ethylbenzene selectivity and the degradation resistance index.

This comparative example is generally performed now.
Β zeolite prepared by ion exchange with ammonium salt. No Al ions exist outside the crystal lattice of zeolite, and the catalyst has catalytic activity only by protons. Compared with the catalyst of the present invention, the conversion of ethylbenzene in the initial stage of the reaction is slightly higher, but the activity is easily deteriorated.

[0043]

[Table 2]

[0044]

The Al-β zeolite of the present invention has higher activity and higher selectivity than other zeolites in the alkylation reaction of aromatic hydrocarbons, without impairing the inherent properties of β zeolite. Demonstrates excellent deterioration resistance. Therefore, industrially, there is an advantage that the productivity can be improved by extending the cycle of regeneration or replacement of the catalyst, and there is an advantage that the amount of the catalyst can be reduced and the equipment can be made more compact. Catalyst.

Claims (3)

[Claims] 1. A β zeolite catalyst having Al ions outside the zeolite crystal lattice, which is used for alkylation of aromatics. 2. The β zeolite catalyst according to claim 1, wherein the Al ion has an aluminum index (V) defined by the following formula (1) and 1 ≦ V ≦ 3. Aluminum index (V) = (LHN) / (AL) (1) (where A is the amount of Al in the zeolite (mmol / g),
N is the amount of Na (mmol / g) in the zeolite;
l and metals other than Na as 0.01 mm
1 / g or more, H is the value obtained by adding the amounts of these metals to the amount of Na, and H is the amount of protons in the zeolite (mmol /
g), L is the amount of Al in the zeolite lattice (mmol /
g). ) 3. At the same time that Al ions are present in an amount of 0.15 mmol or more per dry weight of zeolite, the amount of Al ions with respect to the total amount of protons and Al ions with respect to the cations bound to the zeolite crystal lattice is a molar ratio. The β zeolite catalyst according to claim 1 or 2, wherein the catalyst is 0.4 or more.