JPH11253809A - Ga-beta zeolite catalyst for alkylation of aromatic compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To develop higher activity while maintaining high deterioration resistance and selectivity by making Ga present outside the crystal lattice of a zeolite to be used for alkylation of aromatic compds. SOLUTION: The Ga atoms do not form the zeolite crystalline lattice but are present outside the zeolite crystalline lattice. namely, in the pores and on the surface of the structure. The state of Ga is not limited, and for example, may be in a metal, compd. and ion state. Ga is preferably present as an ion considering that Ga is hardly detached from the zeolite. The kinds and valences of the ion are not limited, and for example, various states such as Ga(OH)2 <+> , GaO<+> , Ga<3+> , Ga(OH)<2+> may be used. Further, Ga is preferably present in a small radius state so as not to inhibit diffusion in the zeolite pores. The amt. of Ga present outside the zeolite crystal lattice is preferably >=0.05 mmol per the unit dry weight of the zeolite.

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]

2. Description of the Prior Art In industrial processes, alkylation of aromatic hydrocarbons has been carried out 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.
No. 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, if high degradation resistance and selectivity can be exhibited while maintaining high degradation resistance and selectivity, and the activity of the catalyst can be further improved, the amount of catalyst used in the plant should be reduced. Therefore, there is an advantage that the equipment can be made more compact. In addition, it is possible to increase the cycle of regeneration or replacement of the catalyst to improve the productivity.

[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.

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.

JP-A-8-103658 discloses that an alkali metal and / or alkaline earth metal is introduced by an ion exchange method as a catalyst used in the alkylation or transalkylation reaction of an aromatic compound. Described β zeolite. When ion exchange is performed with an alkali metal or the like, improvement in deterioration resistance can be expected, but a marked decrease in activity is also expected.

As described above, there has hitherto not been any technique for β-zeolite catalysts to exhibit higher activity while maintaining the high degradation resistance and selectivity inherent to β-zeolite.

[0010]

DISCLOSURE OF THE INVENTION The present invention provides a β-zeolite which has high activity and high selectivity as compared with other zeolites in the alkylation reaction of aromatic hydrocarbons, without impairing the intrinsic properties of β-zeolite. Ga-β exerts better activity
It is an object to provide a zeolite catalyst.

[0011]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have exerted high activity while maintaining the high deterioration resistance and selectivity inherent in β zeolite. Have Ga outside the zeolite crystal lattice,
The inventors have found a Ga-β zeolite catalyst and have completed the present invention.

That is, the present invention is as follows. 1) β zeolite catalyst having Ga outside the crystal lattice of zeolite, which is used for alkylation of aromatics. 2) The β zeolite catalyst as described in 1 above, wherein Ga exists in an ion state.

(3) The above (1), wherein Ga is present in an amount of 0.05 mmol or more per zeolite dry weight.
Or the β zeolite catalyst according to 2. Hereinafter, the present invention will be described in detail. The activity referred to in the present invention is
The conversion of olefin when the alkylation reaction of the aromatic hydrocarbon is performed under the same conditions, and the selectivity is the ratio of the monoalkylated product in the product.

Zeolite has a structure of a condensed acid of silicate, and is composed of SiO ₄ tetrahedron centered on Si and Si
A substituted AlO ₄ tetrahedra the basic structure, forming a crystal structure sharing the O 2 single tetrahedral have to. β zeolite has a lattice structure having cavities (pores) formed by connecting 12 of these basic structures. The zeolite crystal lattice referred to in the present invention is the above-mentioned cavity (pore)
Refers to a lattice structure having 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.

In the present invention, Ga does not form a zeolite crystal lattice but exists outside the zeolite crystal lattice, that is, in the pores and on the surface of the structure. In particular, when Ga is present as an ion, the ion is present in combination with the anion site of the zeolite crystal lattice.
In the present invention, the abundance of Ga is determined by the fluorescent X-ray (2θ = 3
8.920 Primary filter: F-Ni, target:
Rh, tube voltage: 50 kV, tube current: 50 mA, spectral crystal: LiF, detection: SC). This value is a value per zeolite dry weight, and is obtained by converting the weight reduction rate when the temperature is raised to 300 ° C., determined by TGA, as the moisture content and converting the value to the original value.

When Ga becomes a reaction activating factor, Bro
It is considered that it acts as Lewis acid having a weak acid strength as compared with the proton which is an nsted acid. Therefore, it is considered that by introducing Ga outside the zeolite crystal lattice, the activity of the catalyst can be improved without impairing the deterioration resistance of the catalyst and further imparting higher deterioration resistance.

The amount of Ga existing outside the zeolite crystal lattice is preferably at least 0.05 mmol, more preferably at least 0.15 mmol, based on the dry weight of the zeolite. The amount of Ga is 0.05 mmo per weight of zeolite.
If it is less than 1, sufficient catalytic activity may not be obtained depending on the SiO ₂ / Al ₂ O _{3 of} the zeolite. Further, the upper limit of the amount of Ga is equal to the amount of anion sites in the zeolite crystal lattice when Ga is present as ions. In other cases, it depends on the state of Ga, its distribution, etc., but the introduced Ga inhibits the movement of substances into and out of the pores of the zeolite and the movement of the substance in the pores, resulting in a catalyst. Is the maximum value that does not decrease the activity of

In the present invention, the state of Ga is not particularly limited.
, For example, metals, compounds, and ions
In the form of Difficulty of desorption from zeolite
In this case, Ga is preferably present in an ion state. The
The type of ion and its valence are not particularly limited.
No, for example, Ga (OH)_Two ⁺, GaO⁺, G
a ³⁺, Ga (OH)²⁺Various states such as can be taken. Ma
In addition, it was observed that diffusion in zeolite pores was not hindered more.
In terms of point, a state having a small radius is more preferable.

Β zeolite is disclosed in US Pat. No. 3,308,
No. 069 is a known synthetic crystalline aluminosilicate first described in the specification 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, M is a metal cation, n is the valence of M, w is a value up to 4 depending on dehydration conditions and the type of metal cation, (TEA stands for tetraethylammonium.) In addition, the β zeolite in the present invention includes, in addition to those having the above composition, those obtained by removing organic ammonium salts by calcination or the like. The preparation and properties of this zeolite are described in the specification of the aforementioned U.S. Patent. The synthesized β zeolite is identified by an X-ray diffraction d value described in US Pat. No. 3,308,069. In the above-mentioned β zeolite, M is a metal cation from the synthesis of Na ion or the like, but various metal ions can be introduced by performing cation exchange.

The Ga-β zeolite catalyst of the present invention can be obtained by introducing Ga outside the crystal lattice of the above β zeolite catalyst. The method is not particularly limited, and examples thereof include a method of supporting Ga metal or a Ga compound on zeolite and a method of performing ion exchange with Ga ions. The method for supporting the Ga compound on the zeolite is not particularly limited. For example, a method in which β zeolite is treated with a liquid in which a Ga compound such as Ga ₂ O ₃ is dispersed, filtered, dried, and the Ga compound is used. There is a method of treating with a dissolved solution, evaporating the solvent and then calcining.
Here, the supported Ga metal and its compound are more preferably fine particles.

The method of introducing Ga ions into the zeolite by ion exchange is not particularly limited. For example, the β-zeolite after synthesis and calcination is directly ion-exchanged using an aqueous solution of a Ga salt. There is a way. Here, the Ga salt is not particularly limited.
a ₂ (SO ₄ ) ₃ .18H ₂ O or Ga (NO ₃ ) ₃ .n
H ₂ O is used. In addition, β zeolite is thermodynamically unstable in Al in the crystal lattice and is easily desorbed as compared with other zeolites. Therefore, depending on SiO ₂ / Al ₂ O ₃ , during the ion exchange with the Ga salt, β zeolite depends on In some cases, Al in the lattice is desorbed and a part is ion-exchanged to Al.

Other metals may be introduced into the zeolite together with Ga. Although the method is not particularly limited, there is a method of carrying on zeolite or ion-exchanging simultaneously with Ga or by another treatment. Also, some protons can be used. Here, the amounts of metals and protons other than Ga are not particularly limited. Japanese Patent Application Laid-Open No. 4-187647 describes an aromatic conversion method and a catalyst thereof. However, the amount of Na in the β zeolite used here is specified to be less than 0.04% by weight as Na ₂ O. . 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.

When the Ga-β zeolite catalyst of the present invention is used for an aromatic alkylation reaction, a pure zeolite may be used as a catalyst, but generally, zeolite powder is used as a catalyst such as alumina, silica or clay. Inorganic oxides are used alone or in combination as a binder. The catalyst usually contains 10 to 90% by weight, preferably 60 to 80% by weight of 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 hydrocarbons that can be alkylated using the Ga-β zeolite catalyst of the present invention include, for example,
Benzene, toluene and xylene, including mixtures thereof. The most preferred aromatic hydrocarbon is benzene. The olefin used for the alkyl reaction has 2 to 4 carbon atoms.
For example, dilute ethylene containing ethylene, propylene, 1-butene, 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 Ga-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, for example, the temperature is freely selected from the range of 120 to 300 ° C., the pressure is 10 to 50 atm, and the supply rate of the reaction raw material is 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, preparation of a sample, an evaluation method, etc. are as follows. [Synthesis of β zeolite] Two kinds of β zeolite powder samples were synthesized by the following method.

20% of tetraethylammonium hydroxide
85 g of an aqueous solution, 4.5 g of sodium hydroxide and a predetermined amount of sodium aluminate NaAlO ₂ are slowly added to 200 g of ion-exchanged water, and dissolved by heating to 80 ° C. To the solution thus obtained, a predetermined amount of fused silica, nip seal (Nippon Silica Kogyo; NV-3) is slowly added, and 7 g of β zeolite as a seed crystal is further added. 3 by rotation
Stirred for 0 minutes.

The mixture was then placed in a 500 milliliter autoclave and left at 152 ° C. for 10 days without stirring, producing a large amount of crystalline material. This material was filtered, washed, and dried at 120 ° C. for 24 hours to obtain a crystalline powder. Next, this powder was added to 35
The temperature is gradually raised to 0 to 550 ° C.
Time calcined. The powder after calcination is converted to β by X-ray diffraction.
It was identified as a zeolite. The composition analysis of the powder was determined using fluorescent X-rays.

Table 1 shows the amounts of sodium aluminate and fused silica used in the synthesis and SiO ₂ / Al ₂ O ₃ determined by X-ray fluorescence for each sample.

[0030]

[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 12 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.

The reactor was charged with 30 g of the molded catalyst. Packing of the catalyst is performed at 2
It is performed from the position of 00 mm, and 3 mmφ above and below the catalyst layer.
Stainless steel Dickson packing. Feed rate of benzene from the jacket side entrance of the reactor is 1
It was supplied at 5.5 mol / hr. 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 heating medium of 130 ° C. was circulated through the residual heat jacket, and the temperature of the catalyst section was set to 125 ° C.

Thereafter, just before the entrance to the reactor, ethylene was supplied to benzene at a supply rate of 5.4 mol / hr to carry out the reaction. Under the above conditions, the reaction was performed 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 ethylbenzene selectivity and the ethylene conversion 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 10%. It is determined that the longer the time is, the higher the deterioration resistance of the catalyst is.

[0034]

Example 1 [Preparation of Ga-β zeolite] Using sample 1 shown in Table 1, ion exchange was carried out by the following method. 8g
Of Ga (NO ₃ ) ₃ .nH ₂ O (n = 7 to 9)
Dissolve in milliliters of deionized water and add the solution to 60
The temperature was raised to ° C. To the solution is added 50 powder of β zeolite.
g, and ion-exchanged at 60 ° C. for 3 hours while 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 to obtain Ga-β zeolite.

As a result of evaluating the obtained Ga-β zeolite by the method described above, the Ga content was found to be 0.21 mmo.
1 / g. [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 212 mm. The highest temperature reached in the catalyst layer is 21
1 ° C., at which point the ethylene conversion was 7
9.2%. The deterioration resistance index was 15 hours.

[0036]

Example 2 [Preparation of Ga-β zeolite] Using sample 2 shown in Table 1, ion exchange was carried out by the following method. 18
g of Ga (NO ₃ ) ₃ .nH ₂ O (n = 7 to 9)
Dissolve in 0 ml of deionized water, and dissolve the solution in 6 ml.
The temperature was raised to 0 ° C. Add 5 beta zeolite powder to the solution.
0 g was added, 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 to obtain Ga-β zeolite.

The obtained Ga-β zeolite was evaluated by the method described above. As a result, the Ga content was 0.38 mmo.
1 / g. [Evaluation of Alkylation Reaction] The reactor was set up so that the jacket portion was on the top, and the reaction was carried out in a downward flow system. When the reactor was filled with the catalyst, the catalyst layer was 211 mm. The highest temperature reached in the catalyst layer is 21
8 ° C., at which point the ethylene conversion was 8
0.9%. Further, the deterioration resistance index was 14 hr.

[0038]

Comparative Example 1 [Ion Exchange of β Zeolite] Using Sample 2 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.

As a result of evaluating the obtained β zeolite by the method described above, Ga was not present. [Evaluation of alkylation reaction] Using this zeolite, the reaction was evaluated in the same manner 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 196 ° C. in the middle,
The ethylene conversion at that time was 58.3%.
Further, the deterioration resistance index was 14.5 hr.

This comparative example is generally performed now.
Β zeolite prepared by ion exchange with ammonium salt. Ga does not exist outside the crystal lattice of zeolite. Compared with the catalyst of the present invention, the deterioration resistance index is almost the same, but the ethylene conversion is lower.

[0041]

EFFECT OF THE INVENTION The Ga-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 intrinsic properties of β zeolite. Demonstrate better activity. Therefore, industrially, there is an advantage that the productivity can be improved by increasing 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 Ga outside the crystal lattice of zeolite, which is used for aromatic alkylation. 2. The β zeolite catalyst according to claim 1, wherein Ga exists in an ion state. 3. The method according to claim 1, wherein Ga is contained in an amount of 0.
3. The β zeolite catalyst according to claim 1, wherein the β zeolite catalyst is present in an amount of at least 05 mmol.